Arctic Sea Ice : Forum

Cryosphere => Arctic sea ice => Topic started by: Sterks on August 22, 2017, 12:45:56 AM

Title: The 2017/2018 freezing season
Post by: Sterks on August 22, 2017, 12:45:56 AM
I dare open this thread with the image below. Drift predictions for the 25th, which are similar 26 and 27th.
High pressure will dominate Arctic, broad clear skies with little movement.
Will this strange melting season bring a minimum in August?
Also attached the ensemble average of pressures next five days. This should decrease extent, but the isobars are not very tight...
Title: Re: The 2017 freezing season
Post by: Pavel on August 22, 2017, 08:49:33 AM
So the cold melting season comes to the end and we begin the warm freezing season  :D
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Focean.dmi.dk%2Farctic%2Fplots%2FmeanTarchive%2FmeanT_2017.png&hash=59eb65f128ffbe7ae10e4673b1a7d998)
Title: Re: The 2017 freezing season
Post by: Jim Hunt on August 22, 2017, 12:54:36 PM
Will this strange melting season bring a minimum in August?

I'd hazard an (educated?) guess. No.

Which metric does your "minimum" refer to?
Title: Re: The 2017 freezing season
Post by: Sterks on August 22, 2017, 02:34:59 PM
Not an specific one, but is IJIS extent ok? since this spinned off from the discussion of that thread.
In any case, it will be interesting to see if the minimum happens before or very early September, since the weather does not seem very aggressive.
Title: Re: The 2017 freezing season
Post by: oren on August 22, 2017, 06:36:22 PM
Minimum could come 5th-10th of Sept, but very unlikely in August. I think this thread is too early...
Title: Re: The 2017 freezing season
Post by: gerontocrat on August 22, 2017, 06:49:45 PM
Minimum could come 5th-10th of Sept, but very unlikely in August. I think this thread is too early...
When I see 3 (three) extent gains in a row then I will change my spreadsheets from melt to freeze. Feb 29 is going to be a pain to deal with - I see a fudge coming.
Title: Re: The 2017 freezing season
Post by: Sterks on August 22, 2017, 06:51:28 PM
Minimum could come 5th-10th of Sept, but very unlikely in August. I think this thread is too early...
We'll see
Anemic melting this last stretch of August if you ask me...
Title: Re: The 2017 freezing season
Post by: Ned W on August 22, 2017, 08:02:14 PM
Every JAXA daily minimum so far has been during the two week interval of Sept 7-21.

The linear trend in JAXA extent over the past week is -22690 km2/day.  This is the earliest in the season that such a slow week has occurred.  However, several other years show a similar 7-day slowdown starting soon. 

On average, a slowdown like this occurs 11 days before the minimum ... but it ranges from 28 days before minimum (in 2005) to 2 days after minimum (in 2008).

The fascinating thing, though, is that an early slowdown like this is anticorrelated with an early minimum.  Years with an early slowdown tend to have late minimums, not early ones:

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FkyJSjgR.png&hash=1477a74ab70bc4410ee66e0653d78cd8)

The data are noisy and the standard error is large, but the p-value is highly significant (0.012) at a=0.05.

Based on that model, one would expect the 2017 minimum to be somewhere between days 257-271 (i.e., September 13-27) with a best estimate of day 264 (Sept 20).

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FM0vPjh4.png&hash=7a0f036790665e8cdd950a18670fe7af)

Make of it what you will.
Title: Re: The 2017 freezing season
Post by: Daniel B. on August 22, 2017, 08:46:14 PM
Every JAXA daily minimum so far has been during the two week interval of Sept 7-21.

The linear trend in JAXA extent over the past week is -22690 km2/day.  This is the earliest in the season that such a slow week has occurred.  However, several other years show a similar 7-day slowdown starting soon. 

On average, a slowdown like this occurs 11 days before the minimum ... but it ranges from 28 days before minimum (in 2005) to 2 days after minimum (in 2008).

The fascinating thing, though, is that an early slowdown like this is anticorrelated with an early minimum.  Years with an early slowdown tend to have late minimums, not early ones:

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FkyJSjgR.png&hash=1477a74ab70bc4410ee66e0653d78cd8)

The data are noisy and the standard error is large, but the p-value is highly significant (0.012) at a=0.05.

Based on that model, one would expect the 2017 minimum to be somewhere between days 257-271 (i.e., September 13-27) with a best estimate of day 264 (Sept 20).

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FM0vPjh4.png&hash=7a0f036790665e8cdd950a18670fe7af)

Make of it what you will.

Yes, I would not correlate it with an early minimum just yet.  Many factor go into the exact timing of the minimum, with local weather being one of the largest.  Perhaps the recent slowdown can be correlated with the early snows and mass buildup in Greenland.  This year has been tracking quite closely with last year, which had a minimum of Sept. 10.  Without putting too much into an analysis, that is my guess.  However, I would not put too much faith in predicting a particular day, or even week.
Title: Re: The 2017 freezing season
Post by: greatdying2 on August 22, 2017, 10:04:20 PM
Although the melt has slowed down, particularly surface melt and storm-associated melt due to nice weather, this thread is too soon. OTOH, I'm not sure it even makes sense to have separate melt and freeze threads...
Title: Re: The 2017 freezing season
Post by: Ned W on August 22, 2017, 10:35:24 PM
. OTOH, I'm not sure it even makes sense to have separate melt and freeze threads...
If nothing else, it ensures a switch to a new thread every six months.  That at least keeps it from growing out of control. 
Title: Re: The 2017 freezing season
Post by: Sterks on August 23, 2017, 12:16:26 AM
Although the melt has slowed down, particularly surface melt and storm-associated melt due to nice weather, this thread is too soon. OTOH, I'm not sure it even makes sense to have separate melt and freeze threads...
In your opinion.
In my opinion, it doesn't hurt to speculate in parallel threads during the transition, as usual. And this season has proven colder than expected once and again.

While I still expect some extent drops in the next few days, this weekend may bring another pause. Additionally, temperatures for next week, see ASIG, while GFS the least reliable source, for the last days of August seem falling.

Is there a lot of bottom melt? Or most of the ice bottom-melting at this stage is gone because it was much thinner than usual? No winds, no movement, bottom and lateral melt must be very slow.
Title: Re: The 2017 freezing season
Post by: Neven on August 23, 2017, 12:24:57 AM
As soon as the melting season is over for real, I'll change the title to '2017/2018 freezing season'.  :)

My guess - without looking at too many graphs and maps lately, I must admit - is that the low concentration stuff within the ice pack is filling up, and there's not enough weather to stir things at the periphery. As soon as that's done, melting on the periphery will keep things going very slowly into September.

I think end position 2 will be difficult to attain. Maybe top 3?
Title: Re: The 2017 freezing season
Post by: Sterks on August 23, 2017, 12:26:58 AM
Every JAXA daily minimum so far has been during the two week interval of Sept 7-21.

On average, a slowdown like this occurs 11 days before the minimum ... but it ranges from 28 days before minimum (in 2005) to 2 days after minimum (in 2008).

The fascinating thing, though, is that an early slowdown like this is anticorrelated with an early minimum.  Years with an early slowdown tend to have late minimums.
....
The data are noisy and the standard error is large, but the p-value is highly significant (0.012) at a=0.05.

Based on that model, one would expect the 2017 minimum to be somewhere between days 257-271 (i.e., September 13-27) with a best estimate of day 264 (Sept 20).

Make of it what you will.
Nice.
 Yes, it may happen, at least you have the numbers, I just have the hunch this year will be slow and early, adding noise to the stats. Been a weird melting season.
Title: Re: The 2017 freezing season
Post by: Cid_Yama on August 23, 2017, 12:35:28 AM
There is always somebody trying to rain on the melting season early.  They are ALWAYS wrong.

Every party needs a pooper, that's why we invited you. Party pooper.

It's only August 22.  2016 didn't fall off the cliff until the last couple days of August.

And we have far less volume.
Title: Re: The 2017 freezing season
Post by: Coffee Drinker on August 23, 2017, 05:08:40 AM
According to GFS, the freezing season should start next week in parts of the Canadian archipelago.

Night temperatures of -10C will be expected around Baffin Island.
Title: Re: The 2017 freezing season
Post by: Sterks on August 23, 2017, 10:01:45 AM
Every party needs a pooper, that's why we invited you. Party pooper.
I am not going to respond to your insult.
My speculation has easily been put in question by cold numbers (see Ned's above) and experience (see Neven's above), but it is not affected by insults.
We can make of this, 1 Cross-firing of ad-hominems WUWT Style, 2 A dead thread until the freezing season is well-acknowledged 3 Somewhere to place facts of starting symptoms of the pack refreezing even before the minimum, be it on August or October, ... or not refreezing if you wish
I prefer 2 or 3
Title: Re: The 2017 freezing season
Post by: Ned W on August 23, 2017, 12:06:09 PM
Keep in mind that the current "melting season" thread was started on January 1 and had dozens of posts in January and February, and over 100 posts before the end of the freezing season.  There's absolutely nothing wrong with starting this thread now.

It makes sense for them to overlap, because the freezing season starts in some parts of the Arctic while the melting season is still finishing up in other parts.
Title: Re: The 2017 freezing season
Post by: Shared Humanity on August 23, 2017, 01:28:22 PM
Keep in mind that the current "melting season" thread was started on January 1 and had dozens of posts in January and February, and over 100 posts before the end of the freezing season.  There's absolutely nothing wrong with starting this thread now.

It makes sense for them to overlap, because the freezing season starts in some parts of the Arctic while the melting season is still finishing up in other parts.

And the three measures (extent, area and volume) behave differently during the transition.
Title: Re: The 2017 freezing season
Post by: echoughton on August 23, 2017, 01:47:08 PM
I Love this forum. SO much incredible talent and science. Yet it usually settles in on opinion. LOL.
With the wild slowdown and near-future weather forecast...it may still be possible that my 4.75-5 mil sq K prediction could happen.
Title: Re: The 2017 freezing season
Post by: Pavel on August 23, 2017, 02:17:42 PM
Looking everywhere on the SSTs one can expect sluggish ice growth both in Inner Basin and peripheral. The extent curve can dip lower than 2016. Not only in summer the cannonballs could appear
Title: Re: The 2017 freezing season
Post by: Ned W on August 23, 2017, 02:56:31 PM
I used Wipneus's file of daily PIOMAS volumes aggregated by region to make this chart, which shows the start of the freezing season for each basin, for each year (2000-2016):

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FKpaGWJL.png&hash=d297dc1ec645a6441b44100588683f4e)

The Y axis is day of year.  There are big and consistent differences in terms of the onset of freezing from basin to basin (note the positions of the diamonds, which are the median date of the start of the freezing season).

Medians, sorted from earliest to latest:
GrnLS   237   25-Aug
Baffn   247   4-Sep
CAB   256   13-Sep
CAA   257   14-Sep
Hudsn   257   14-Sep
Beauf   263   20-Sep
KaraS   264   21-Sep
Laptv   265   22-Sep
Baren   266   23-Sep
ESS   267   24-Sep
Chukc   270   27-Sep
Okhot   311   7-Nov
Berng   312   8-Nov

Comments, corrections, suggestions for improvement etc. are welcome.

Annoying details:  I defined the start of the freezing season as the date of the first increase in volume after the minimum.  If a basin hits the same minimum repeatedly during a single year, it's the day after its first minimum (maybe it would be better to have used the last, but no big deal). A couple of random weird outliers (noise) were deleted.
Title: Re: The 2017 freezing season
Post by: jplotinus on August 23, 2017, 04:45:17 PM
According to GFS, the freezing season should start next week in parts of the Canadian archipelago.

Night temperatures of -10C will be expected around Baffin Island.

What is source for -10° temps "around Baffin Island"? Weather forecast for Clyde River, which is at middle of east coast of Baffin, has temps above 0° throughout next nine days, with highs above 10° for some of them.
Title: Re: The 2017 freezing season
Post by: Sterks on August 23, 2017, 06:27:31 PM
@Ned nice job, for further discredit of my opening post :)
For the last metric, I was expecting area to really start reaching bottom, but not really. As unusual as this season usually has been. The area curve should be getting flat now and extent keep dropping, not the opposite.
Title: Re: The 2017 freezing season
Post by: oren on August 23, 2017, 07:00:38 PM
Ned very interesting. Off the cuff, most areas minimum is determined by export into them. Best shown by the Greenland Sea. The CAB is really the best indicator for real freezing onset.
In addition I suspect your criteria are picking up weirdness somehow. Hudson refreezing on day 220? Bering refreezing before Chukchi? Possibly small transitory blips cause this. Maybe add a threshold criterion of an absolute or percentage gain to mark a day as past the minimum. And/or use the last time at the minimum rather than the first.
Title: Re: The 2017 freezing season
Post by: magnamentis on August 23, 2017, 07:04:55 PM
@Ned nice job, for further discredit of my opening post :)
For the last metric, I was expecting area to really start reaching bottom, but not really. As unusual as this season usually has been. The area curve should be getting flat now and extent keep dropping, not the opposite.

@Ned nice job, for further discredit of my opening post :)
For the last metric, I was expecting area to really start reaching bottom, but not really. As unusual as this season usually has been. The area curve should be getting flat now and extent keep dropping, not the opposite.

thanks for opening this thread now. the price for thinking or even acting ahead of the main stream seems to be high enough once more, i, like yourself, find it interesting to speculate the transition now that the season once more has proven it's "off any norm status" sooner or later we probably need a rule for opening such threads, until then i enjoy this and more to come. IMO it would even be possible to discuss the impact on much earlier states of the melting season on the coming freezing season. perhaps some people planned to open the freezing thread themselves ? ;)
Title: Re: The 2017 freezing season
Post by: Ned W on August 23, 2017, 07:42:36 PM
Ned very interesting. Off the cuff, most areas minimum is determined by export into them. Best shown by the Greenland Sea. The CAB is really the best indicator for real freezing onset.
In addition I suspect your criteria are picking up weirdness somehow. Hudson refreezing on day 220? Bering refreezing before Chukchi? Possibly small transitory blips cause this. Maybe add a threshold criterion of an absolute or percentage gain to mark a day as past the minimum. And/or use the last time at the minimum rather than the first.
Great, this is exactly the response I wanted.

* Yes, it's quite possible that export (er, "import" in this case) is actually what produces the first rise after minimum in many basins in many years.

* Yes, some of the "weirdness" you identified was due to my poor choice of using the first increase after the first instance of the minimum.  I've now re-done the graph using the first day of increase after the last instance of the minimum:

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FX8WRugT.png&hash=555e06d0802cfe99ca1d001696d8b5cc)

The results are somewhat different, including addressing both the points of weirdness that you identified (though in 2000 the Bering still shows its first increase only three days after the Chukchi). 

Here are the updated medians:

GrnLS   239   26-Aug
Baffn   250   7-Sep
CAB   256   13-Sep
CAA   258   15-Sep
KaraS   265   22-Sep
Beauf   266   23-Sep
Laptv   268   25-Sep
ESS   269   26-Sep
Baren   270   27-Sep
Chukc   273   30-Sep
Hudsn   274   1-Oct
Okhot   311   7-Nov
Berng   312   8-Nov

I'm going to continue to think about this and see if I can come up with further improvements.
Title: Re: The 2017 freezing season
Post by: Sterks on August 23, 2017, 10:44:14 PM
Ned very interesting. Off the cuff, most areas minimum is determined by export into them. Best shown by the Greenland Sea. The CAB is really the best indicator for real freezing onset.
In addition I suspect your criteria are picking up weirdness somehow. Hudson refreezing on day 220? Bering refreezing before Chukchi? Possibly small transitory blips cause this. Maybe add a threshold criterion of an absolute or percentage gain to mark a day as past the minimum. And/or use the last time at the minimum rather than the first.
Great, this is exactly the response I wanted.

* Yes, it's quite possible that export (er, "import" in this case) is actually what produces the first rise after minimum in many basins in many years.

* Yes, some of the "weirdness" you identified was due to my poor choice of using the first increase after the first instance of the minimum.  I've now re-done the graph using the first day of increase after the last instance of the minimum:

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FX8WRugT.png&hash=555e06d0802cfe99ca1d001696d8b5cc)

The results are somewhat different, including addressing both the points of weirdness that you identified (though in 2000 the Bering still shows its first increase only three days after the Chukchi). 

Here are the updated medians:

GrnLS   239   26-Aug
Baffn   250   7-Sep
CAB   256   13-Sep
CAA   258   15-Sep
KaraS   265   22-Sep
Beauf   266   23-Sep
Laptv   268   25-Sep
ESS   269   26-Sep
Baren   270   27-Sep
Chukc   273   30-Sep
Hudsn   274   1-Oct
Okhot   311   7-Nov
Berng   312   8-Nov

I'm going to continue to think about this and see if I can come up with further improvements.
Greatness! Thanks Oren for suggesting the improvement.
We don't have a NASA cluster yet a nice list of what to expect region by region in the coming weeks based on past years, that's more than expected. Thanks Ned.
Of course there is the unpredictability component.
Title: Re: The 2017 freezing season
Post by: Cid_Yama on August 23, 2017, 11:41:51 PM
According to GFS, the freezing season should start next week in parts of the Canadian archipelago.

Night temperatures of -10C will be expected around Baffin Island.

What is source for -10° temps "around Baffin Island"? Weather forecast for Clyde River, which is at middle of east coast of Baffin, has temps above 0° throughout next nine days, with highs above 10° for some of them.

Thank you for jumping on that.  We don't need any disinformation.
Title: Re: The 2017 freezing season
Post by: Coffee Drinker on August 24, 2017, 02:13:23 AM
According to GFS, the freezing season should start next week in parts of the Canadian archipelago.

Night temperatures of -10C will be expected around Baffin Island.

What is source for -10° temps "around Baffin Island"? Weather forecast for Clyde River, which is at middle of east coast of Baffin, has temps above 0° throughout next nine days, with highs above 10° for some of them.

Thanks for the correction and sorry for the confusion. I mean Ellesmere Island not Baffin. Looked mostly at the station Eureka and the GFS 2m temp forecast from GFS.

Baffin is indeed very far from freezing conditions at this stage. Sorry again.

GFS has backed off now a little but still freezing weather expected from next week. Will be exciting to see the first new ice of the year.

Title: Re: The 2017 freezing season
Post by: Archimid on August 24, 2017, 02:27:05 PM
Thank you Ned W. I took the liberty to use ASIG's regional map and added the median day for the beginning of the freezing season to help me visualize it better.
Title: Re: The 2017 freezing season
Post by: Ned W on August 24, 2017, 04:58:12 PM
Very nice, Archimid!  The map definitely helps visualize this.

I've been messing around with this some more, and thought this was a useful comparison:

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FdyR3SZF.png&hash=d37a445dcdca5e84e1ea9578bcb2c699)

The first day of refreeze is calculated as before.  The first week represents the start of the first seven-day period of continuous increases in volume after the last day at the minimum.

The graph shows the means, but medians are probably better, and they're what Archimid used on the map, so here they are:

Okhot: first week = 336 (02-Dec) first day = 311 (07-Nov)
Berng: first week = 336 (02-Dec) first day = 312 (08-Nov)
Beauf: first week = 276 (03-Oct) first day = 266 (23-Sep)
Chukc: first week = 289 (16-Oct) first day = 273 (30-Sep)
ESS: first week = 272 (29-Sep) first day = 269 (26-Sep)
Laptv: first week = 277 (04-Oct) first day = 268 (25-Sep)
KaraS: first week = 276 (03-Oct) first day = 265 (22-Sep)
Baren: first week = 297 (24-Oct) first day = 270 (27-Sep)
GrnLS: first week = 249 (06-Sep) first day = 237 (25-Aug)
CAB: first week = 264 (21-Sep) first day = 256 (13-Sep)
CAA: first week = 268 (25-Sep) first day = 258 (15-Sep)
Baffn: first week = 280 (07-Oct) first day = 250 (07-Sep)
Hudsn: first week = 304 (31-Oct) first day = 274 (01-Oct)

Title: Re: The 2017 freezing season
Post by: jplotinus on August 24, 2017, 06:13:04 PM
According to GFS, the freezing season should start next week in parts of the Canadian archipelago.

Night temperatures of -10C will be expected around Baffin Island.

What is source for -10° temps "around Baffin Island"? Weather forecast for Clyde River, which is at middle of east coast of Baffin, has temps above 0° throughout next nine days, with highs above 10° for some of them.

Thanks for the correction and sorry for the confusion. I mean Ellesmere Island not Baffin. Looked mostly at the station Eureka and the GFS 2m temp forecast from GFS.

Baffin is indeed very far from freezing conditions at this stage. Sorry again.

GFS has backed off now a little but still freezing weather expected from next week. Will be exciting to see the first new ice of the year.

Thanks for your clarification. In 2017, Arctic sea ice extent has been as enigmatic as ever. I think all any of us can do with confidence is observe and try to interpret as best we can. The sea ice is telling us something, for sure.
Title: Re: The 2017 freezing season
Post by: Ned W on August 24, 2017, 08:00:04 PM
Right now it seems to be telling us that summer is ending and fall is on the way.  With all due respect to the ice, I could really use another month of summer!  Not ready for fall yet...
 :)
Title: Re: The 2017 freezing season
Post by: Dharma Rupa on August 24, 2017, 08:06:15 PM
Not ready for fall yet...
 :)
Fall is the second best season!   I've have enough of the heat and humidity.
Title: Re: The 2017 freezing season
Post by: Niall Dollard on August 25, 2017, 01:14:58 PM
Given that frazil ice can start to form when air temps are down to -6 C, we are not far off that figure according to nullschool at 85N 77W.
Title: Re: The 2017 freezing season
Post by: jplotinus on August 25, 2017, 08:31:57 PM
Given that frazil ice can start to form when air temps are down to -6 C, we are not far off that figure according to nullschool at 85N 77W.

Alert, at the north coast and of Ellesmere, is now experiencing below 0° temps on a daily basis, but not yet down to -6°
Since the Arctic summer has been 'cool', I wonder whether the autumn will revert to mean by being relatively warmer?
Title: Re: The 2017 freezing season
Post by: Dharma Rupa on August 25, 2017, 10:06:21 PM
Given that frazil ice can start to form when air temps are down to -6 C, we are not far off that figure according to nullschool at 85N 77W.

Alert, at the north coast and of Ellesmere, is now experiencing below 0° temps on a daily basis, but not yet down to -6°
Since the Arctic summer has been 'cool', I wonder whether the autumn will revert to mean by being relatively warmer?
I think you want to watch this for an answer:
Title: Re: The 2017 freezing season
Post by: Quantum on August 26, 2017, 02:57:45 AM
I would be gobsmacked if the melting season ended in August. Though I suppose stranger things have happened to the ice.
Title: Re: The 2017 freezing season
Post by: Shared Humanity on August 26, 2017, 04:21:40 PM
Given that frazil ice can start to form when air temps are down to -6 C, we are not far off that figure according to nullschool at 85N 77W.

Alert, at the north coast and of Ellesmere, is now experiencing below 0° temps on a daily basis, but not yet down to -6°
Since the Arctic summer has been 'cool', I wonder whether the autumn will revert to mean by being relatively warmer?

Arctic winters have been anomalously warmer for more than a decade. Yes, the 2016 winter was a record breaker but 2015 was ridiculously warm as well except when compared to 2016. You have to go back to 2004 before you find a winter where temperatures tracked with the 1958-2017 mean.

I am absolutely convinced this is the result of an emerging new Arctic climate regime and would be very surprised if winters do not continue to be anomalously warm.
Title: Re: The 2017 freezing season
Post by: Niall Dollard on August 27, 2017, 06:53:23 PM
A useful eye witness account from Pen Hadow's Arctic Mission which gives an on the spot idea of conditions at about 80 N around 4 hours ago. Very early stages yet for sea water freezing. (Even if they dont make 90N still they are still gathering useful data on the Arctic)

A missive from expedition co-leader and Bagheera skipper Erik de Jong: 'It's shocking to see how open the water is, almost no ice of any significance, therefore we can sail practically the course we want and at full speed. It is pretty cold out here, the air is a few degrees below freezing, and the water is a couple degrees below freezing. Due to the salinity of the seawater, it remains liquid, but it is border line. Fresh water patches are frozen, and so is the bottom of our fresh water tank! The pick up line for fresh water is  frozen shut and there is no more water coming out of the faucet. The prediction is that warmer waters from the south are moving in shortly, so it should remedy itself over the next few days. In the meantime, we have our backup supply in portable barrels  in the galley and I've hung a hose connected to the water pump, so that water can be used again. This will work for a week to 10 days without rationing usage. If the tank remains frozen till that time, there are some other tricks we can pull to get the water out of the tank. During the science experiments we are often anchored to an ice floe so that we don't move to fast and that we don't have to keep an eye on where the boats are drifting. Many of these floes have had several inches of fresh snow on them. We are collecting that in buckets and are able to add to our water supply that way too.'
Title: Re: The 2017 freezing season
Post by: Sterks on August 27, 2017, 08:43:03 PM
Thanks Niall. I read in the dedicated ASIF thread that they are approaching the pack through the Beaufort bite, and if this is 80 N , they are just at the edge of broken ice.
Is there a web where they are posting regular updates and their location?
Title: Re: The 2017 freezing season
Post by: Niall Dollard on August 28, 2017, 02:10:47 AM
Hi Sterks

This link will get you regular updates of their current location:

http://www.arcticmission.com/follow-arctic-mission/ (http://www.arcticmission.com/follow-arctic-mission/)

Title: Re: The 2017 freezing season
Post by: weatherdude88 on August 28, 2017, 01:36:11 PM
Our first candidate for NSIDC arctic sea ice extent minimum is 8.25.2017. The NSIDC arctic sea ice extent metric is up 92 thousand Kilometers squared the past two days. The JAXA sea ice extent metric also recorded an increase today. 

ftp://sidads.colorado.edu/DATASETS/NOAA/G02135/north/daily/data/N_seaice_extent_daily_v2.1.csv
Title: Re: The 2017 freezing season
Post by: Sterks on August 28, 2017, 02:00:57 PM
Hi Sterks

This link will get you regular updates of their current location:

http://www.arcticmission.com/follow-arctic-mission/ (http://www.arcticmission.com/follow-arctic-mission/)

Thank you!
Title: Re: The 2017 freezing season
Post by: Ned W on August 28, 2017, 02:53:12 PM
Are first candidate for NSIDC arctic sea ice extent minimum is 8.25.2017. The NSIDC arctic sea ice extent metric is up 92 thousand Kilometers squared the past two days. The JAXA sea ice extent metric also recorded an increase today. 

ftp://sidads.colorado.edu/DATASETS/NOAA/G02135/north/daily/data/N_seaice_extent_daily_v2.1.csv
It's unlikely, but of course possible that this was the minimum.  If it turns out that way, Sterks can take a bow and the rest of us will applaud. 

 :)


-----------
Edited to add:  If this was in fact the minimum (which it wasn't  8) ) then we collectively did abysmally badly in the June/July/August JAXA polls.  # of predictions above 4.75:
June: 1 of 122
July: 1 of 122
August: 3 of 105
Title: Re: The 2017 freezing season
Post by: Daniel B. on August 28, 2017, 05:36:58 PM
Are first candidate for NSIDC arctic sea ice extent minimum is 8.25.2017. The NSIDC arctic sea ice extent metric is up 92 thousand Kilometers squared the past two days. The JAXA sea ice extent metric also recorded an increase today. 

ftp://sidads.colorado.edu/DATASETS/NOAA/G02135/north/daily/data/N_seaice_extent_daily_v2.1.csv
It's unlikely, but of course possible that this was the minimum.  If it turns out that way, Sterks can take a bow and the rest of us will applaud. 

As a reminder, 2016 saw a large rebound of 170 thousand km2 on Aug. 28, only to decline for another 10 days, reaching a minimum on Sept. 7.  By as Ned says, it is possible.
Title: Re: The 2017 freezing season
Post by: Pavel on August 28, 2017, 06:14:35 PM
Yesterday snowfalls in some parts of Siberia are month earlier than usual. Snow depth in north-west Yakutia is 10cm what is the biggest ever for 27 of August, according to a russian wheather TV
Title: Re: The 2017 freezing season
Post by: Sterks on August 28, 2017, 07:47:42 PM
The inverted dipole that has seized the Arctic will be pulling air from the Atlantic/Asia and compacting the ice North of Barents, so I would expect more extent loses. But the winds across the Arctic become Northernlies at the broken ice edge of the Pacific side, where one would expect those sudden refreezes like last year would happen first. So who knows.
Title: Re: The 2017 freezing season
Post by: jplotinus on August 29, 2017, 06:34:43 AM
The inverted dipole that has seized the Arctic will be pulling air from the Atlantic/Asia and compacting the ice North of Barents, so I would expect more extent loses. But the winds across the Arctic become Northernlies at the broken ice edge of the Pacific side, where one would expect those sudden refreezes like last year would happen first. So who knows.

Yup. "Who knows"? A second small uptick per JAXA on 8/28.  😯
Title: Re: The 2017 freezing season
Post by: weatherdude88 on August 29, 2017, 01:52:04 PM
NSIDC northern hemisphere sea ice extent had another uptick today. we are now 102000 Kilometers squared above 8.25.2017. 8.28.2017 is now the highest value in the last 5 days.
Title: Re: The 2017 freezing season
Post by: Sterks on August 30, 2017, 09:11:39 AM
Significant cooling and snowing over the CAB toward the Beaufort side in the next days. The snow models of ESRL and GFS:
https://www.esrl.noaa.gov/psd/forecasts/seaice/ (https://www.esrl.noaa.gov/psd/forecasts/seaice/)
Not sure how to bring these animations here out of the noaa page.
The winds seem to keep pushing the ice from the South at Laptev and ESS from this model.
Title: Re: The 2017 freezing season
Post by: Ned W on August 30, 2017, 11:53:38 AM
Surprise! (or not)  -- it turns out that Aug 26 was not the JAXA extent minimum.  A pretty normal drop yesterday. 
Title: Re: The 2017 freezing season
Post by: Shared Humanity on August 30, 2017, 07:07:12 PM
Surprise! (or not)  -- it turns out that Aug 26 was not the JAXA extent minimum.  A pretty normal drop yesterday.

Not....at least not for me.
Title: Re: The 2017 freezing season
Post by: Brigantine on September 04, 2017, 11:42:00 PM
The re-freeze has now reached CIS maps.

Peabody bay as of 2017-09-04 18Z has 1/10 new ice alongside the 2/10 - 9/10 of one-summer-old ice. (Eureka - WIS36CT)

BTW, is this necessarily the result of freezing? Or is it possibly snow?
Title: Re: The 2017 freezing season
Post by: Ned W on September 05, 2017, 02:50:57 PM
That's three consecutive days of increasing extent in JAXA, since 1 September.  There are often several days of "false start" like this, but 2017 is tied with 2004 for the earliest three-day period of consecutive increases.  2015 had a similar run of three days starting a day later.
Title: Re: The 2017 freezing season
Post by: Tealight on September 06, 2017, 11:24:48 AM
By now over 95% of this years solar energy was either absorbed or reflected by the Arctic Ocean and I can finally post my refreeze-forecast.

When thinking about refreezing, the lowest sea minimum should also correlate with a low sea ice area / extent during the freezing season because a lot of open water has to refreeze. But the September minimum isn't quite as good as my AWP anomaly calculation, which considers absorbed heat by the oceans as well. For the last 11 years I compared the sea ice area minimum, the sea ice extent minimum and the cumulative AWP anomaly against the average sea ice area and extent anomaly during the October-December refreeze.

An Overview about individual years can be found here:
https://sites.google.com/site/cryospherecomputing/warming-potential


The AWP correlation is negative, because a higher solar energy absorption results in a slower refreeze, hence a negative area anomaly. See the attached graph for all 11 years.(the zero line is not the same for both axis and the secondary axis is inverted due to the negative correlation)

Correlation with Oct-Dec Extent anomaly
Minimum Area   0.779236221
Minimum Extent   0.699103822
Cumu AWP anomaly   -0.84296024
   
Correlation with Oct-Dec Area anomaly
Minimum Area   0.748245297
Minimum Extent   0.637113296
Cumu AWP anomaly   -0.784477392

Surprisingly for me all forecast methods correlate better with the sea ice extent anomaly and not the sea ice area anomaly. The ranking however always stays the same. The best is my cumulative AWP anomaly, followed by the sea ice area minimum and least skillful is the sea ice extent minimum.

For 2017 with a "cumu AWP" of +15.8 MJ/m2 we should expect an average extent anomaly of -0.22 million km2

Edit: without 2009 the AWP anomaly would correlate to 94% with sea ice extent and 93% with sea ice area
Title: Re: The 2017 freezing season
Post by: Niall Dollard on September 06, 2017, 11:13:20 PM
The re-freeze has now reached CIS maps.


Yes. Today's map shows an area of pink (new ice) in the Kane Basin.

My interest today though switched to the Nansen Sound above Eureka, Ellesmere Island.

Eosdis Worldview image shows a lot of what looks like new ice in the sound (esp compared with previous clear image on 4th Sep).

However Sentinel does provide a nice close up of Nansen Sound on the 4th with some new ice.
Title: Re: The 2017 freezing season
Post by: Niall Dollard on September 10, 2017, 12:06:43 PM
An animated GIF on the thickening new ice in Nansen Sound, Ellesmere Island 3rd to 9th Sept.
Title: Re: The 2017 freezing season
Post by: 2phil4u on September 10, 2017, 04:10:10 PM
By now over 95% of this years solar energy was either absorbed or reflected by the Arctic Ocean and I can finally post my refreeze-forecast.

When thinking about refreezing, the lowest sea minimum should also correlate with a low sea ice area / extent during the freezing season because a lot of open water has to refreeze. But the September minimum isn't quite as good as my AWP anomaly calculation, which considers absorbed heat by the oceans as well. For the last 11 years I compared the sea ice area minimum, the sea ice extent minimum and the cumulative AWP anomaly against the average sea ice area and extent anomaly during the October-December refreeze.

An Overview about individual years can be found here:
https://sites.google.com/site/cryospherecomputing/warming-potential


The AWP correlation is negative, because a higher solar energy absorption results in a slower refreeze, hence a negative area anomaly. See the attached graph for all 11 years.(the zero line is not the same for both axis and the secondary axis is inverted due to the negative correlation)

Correlation with Oct-Dec Extent anomaly
Minimum Area   0.779236221
Minimum Extent   0.699103822
Cumu AWP anomaly   -0.84296024
   
Correlation with Oct-Dec Area anomaly
Minimum Area   0.748245297
Minimum Extent   0.637113296
Cumu AWP anomaly   -0.784477392

Surprisingly for me all forecast methods correlate better with the sea ice extent anomaly and not the sea ice area anomaly. The ranking however always stays the same. The best is my cumulative AWP anomaly, followed by the sea ice area minimum and least skillful is the sea ice extent minimum.

For 2017 with a "cumu AWP" of +15.8 MJ/m2 we should expect an average extent anomaly of -0.22 million km2

Edit: without 2009 the AWP anomaly would correlate to 94% with sea ice extent and 93% with sea ice area

Do you talk about the difference of the anomaly now and the anomaly later ?
So if now for example we have -1 Mio, a Dezember of -1.2 Mio  is 200k change ?
Why dont you take the invert instead of getting a negative correlation.
In general i think in very low ice years we see a stronger refreeze, so if we have 3 Mio Minimum, in November we  surely have less then with a 5 Mio Minimum, but not 2 Mio less i guess.
Maybe you can find a formula that fits optimal for the years,you can also change the Nov values a bit if you think weather was unusal.
Title: Re: The 2017 freezing season
Post by: Pavel on September 10, 2017, 05:04:22 PM
2017 looks warmer in the Laptev\ESS\Chuckchi than 2016. It's colder in the Kara\Barents but this side hit by fall\winter warm cyclones and freezing momentum is weak there. In general one should expect mild fall and sluggish ice growth
Title: Re: The 2017 freezing season
Post by: Pavel on September 11, 2017, 07:30:58 PM
Comparing some clear Wolrdview views from 30 of July and today we see the surface refreeze have taked place north of Greenland. Also there was significant ice retreat near Svalbard where it was 4-metres thick ice at the start of melting
Title: Re: The 2017 freezing season
Post by: Brigantine on September 13, 2017, 10:49:05 PM
My interest today though switched to the Nansen Sound above Eureka, Ellesmere Island.

Wise choice. That's the only place anywhere showing grey ice floes forming on the weekly CIS maps released today. (Eastern Arctic, areas V and EE have up to 3/10 of grey ice as 20-100m floes within the pink ice)
Title: Re: The 2017 freezing season
Post by: Niall Dollard on September 14, 2017, 07:41:40 PM
Ah yes Brigantine, Ellesmere and north Greenland the last cold bastion of the northern Hemisphere.  :)

There have been some nice clear images this September and looking back through Worldview on 10th September, it looks a lot more frozen than on the same date last year. (images attached, one year apart).  A little better than the other years shown on Worldview but I expect it's not that much different to what climatology would suggest, but maybe snow is a little more deep and extensive.

My hope for this freezing season is that the Ellesmere/Greenland cold will spread/extend readily across the CAA. The tongue in the eastern Beaufort should help the ice to develop in that section and help close the Beaufort Bite.

The western Beaufort and Chukchi will be problematic due to high SSTs and I expect slow extension into these seas.

I'd hope there is early/extensive/deep snowfall across the top of Russia. Snow and associated low autumnal temps could help the pack extend readily through the Laptev/Kara and ESS. But as it stands there is a considerable gap between the ice edge and Russia. I think if we do not see a good extension of a solid pack covering much of the Arctic Basin quite soon, the DMI N80 temps will struggle once again to reach the ERA40 (1958-2002) mean over the winter half of the year (like last year). Already the drift away from the old "norm" has begun . http://ocean.dmi.dk/arctic/meant80n.uk.php (http://ocean.dmi.dk/arctic/meant80n.uk.php)

The SSTs in the Barents perplexes me. Especially in the northern part. Typically the last few years, the SSTs in the Barents have been very high. Recent months they are lower. But I doubt if this will have much significant effect on ice extension until maybe late this Winter/Spring as no doubt there will be many autumn/winter Atlantic storms to come preventing ice extension.

Having said all this, it can and probably will all go pear shaped and we will end up next May with yet another thin/weak pack. It looks like we will still be scratching around hanging on until the next big El Nino year wreaks havoc. Probably needs a miracle at this stage or somehow a plateauing of CO2 emissions.

Title: Re: The 2017 freezing season
Post by: Brigantine on September 15, 2017, 09:33:34 AM
A reasonable amount of pink ice forming in the Chukchi sea (per CIS).

At 78N, only where the surface waters are kept chilled by melting open drift ice from last winter, and even then it's patchy. (for reference: at 78N, 135W - 150W)

Compared with the same date 2014 and 2015, the re-freeze this year is a bit further advanced.
(and surviving ice much sparser)

Though by this date (+1 day) in 2016 at the same latitude, the refreeze had already developed even further - comprehensive new ice (9+/10) in areas without more than a trace of surviving ice, and around open drifts of surviving ice the re-freeze was already at the stage that Nansen Sound is this year (on 2017-09-11).
Title: Re: The 2017 freezing season
Post by: Niall Dollard on September 15, 2017, 06:19:03 PM
Yes on many of the CIS regional maps Chukchi/Beaufort/Northern parts of CAA, there are many areas now coloured pink (new ice).

It has been cold. For the week ending Sept 11th mean temp at Eureka was -8.8 C (norm -4.3) and Resolute -3.4 C (norm -2.8 ).
Title: Re: The 2017/2018 freezing season
Post by: Thomas Barlow on September 16, 2017, 10:43:58 PM
Judging by this, the Arctic Ocean itself (ignoring all peripherals such as CAA and Fram, etc., and thick ice crushed against land - "bits of ice stuck to land", as Wadhams puts it, re. a future 'Blue Ocean Event') looks like the overall ocean itself (ignoring fjords and coastal build-up) is about as bad a state as it gets for volume, maybe worst, at the start of freezing season.
Title: Re: The 2017/2018 freezing season
Post by: Niall Dollard on September 16, 2017, 11:53:31 PM
Judging how, by eye, Thomas ? As to pronounce which is worst, I wouldn't wish to comment as brain/eye can be deceptive.
Title: Re: The 2017/2018 freezing season
Post by: Pavel on September 16, 2017, 11:53:58 PM
Very much of survived FY ice. The ice formed last October in the Laptev sea now above the Pole. Another issue is that export goes mostly to the Beaufort but not Fram strait. In general the start of refreeze in terms of accumulated FDD is similar with 2016. It will take a long while when the periphery seas start to freeze up. The question should be whether the  freezing season will be very mild or extremely mild
Title: Re: The 2017/2018 freezing season
Post by: Thomas Barlow on September 17, 2017, 12:37:53 AM
Judging how, by eye, Thomas ? As to pronounce which is worst, I wouldn't wish to comment as brain/eye can be deceptive.
No, not really. It's pretty clear to a well trained eye. ;-)
Title: Re: The 2017/2018 freezing season
Post by: Pavel on September 18, 2017, 06:48:30 PM
These two DMI graphs of north of 80 latitude temps and Greenland ice sheet mass budget pretty show the mild and snowy story continues. Could be a pattern for the whole season
Title: Re: The 2017/2018 freezing season
Post by: Alec aka Daffy Duck on September 19, 2017, 01:06:14 AM
Kara and Barents seas SSTs still much colder than last year, especially along where the existing ice is:

Sept 18, 2016
https://www7320.nrlssc.navy.mil/hycomARC/navo/arcticsst/nowcast/sst2016091718_2016091800_046_arcticsst.001.gif

sept 18, 2017
https://www7320.nrlssc.navy.mil/hycomARC/navo/arcticsst/nowcast/sst2017091718_2017091800_046_arcticsst.001.gif
Title: Re: The 2017/2018 freezing season
Post by: Daniel B. on September 19, 2017, 03:28:08 PM
These two DMI graphs of north of 80 latitude temps and Greenland ice sheet mass budget pretty show the mild and snowy story continues. Could be a pattern for the whole season

Already ahead of the pace set in 2016/17.
Title: Re: The 2017/2018 freezing season
Post by: Shared Humanity on September 19, 2017, 03:57:12 PM
These two DMI graphs of north of 80 latitude temps and Greenland ice sheet mass budget pretty show the mild and snowy story continues. Could be a pattern for the whole season

Already ahead of the pace set in 2016/17.

Our climate is changing. We should expect to be surprised by new persistent features of this changing climate. With more moisture in our atmosphere, increased snowfall would seem to be a logical result.
Title: Re: The 2017/2018 freezing season
Post by: Shared Humanity on September 19, 2017, 04:02:23 PM
These two DMI graphs of north of 80 latitude temps and Greenland ice sheet mass budget pretty show the mild and snowy story continues. Could be a pattern for the whole season

A snowier Greenland would suggest a snowier Arctic Ocean as well, at least on the Atlantic side. This was a point of heated discussion during the just completed melt season. If the Atlantic cyclone cannon fires up like it did last winter, I would think that more snow would fall. Could this heavier snowfall explain the conditions we find on the Atlantic side of the Arctic where the ice was remarkably resistant to melt?
Title: Re: The 2017/2018 freezing season
Post by: Daniel B. on September 19, 2017, 05:14:43 PM
These two DMI graphs of north of 80 latitude temps and Greenland ice sheet mass budget pretty show the mild and snowy story continues. Could be a pattern for the whole season

Already ahead of the pace set in 2016/17.

Our climate is changing. We should expect to be surprised by new persistent features of this changing climate. With more moisture in our atmosphere, increased snowfall would seem to be a logical result.

That would be true only for those locations consistently below freezing.  Otherwise, we would expect more of the snow to fall as rain.
Title: Re: The 2017/2018 freezing season
Post by: Dharma Rupa on September 19, 2017, 05:21:05 PM
That would be true only for those locations consistently below freezing.  Otherwise, we would expect more of the snow to fall as rain.
I think you can use the northward march of the permafrost and several species of trees as a pretty good proxy for the rain/snow line.  Still far enough south that I think we can expect plenty of snow this winter, but maybe not a decade from now.

Title: Re: The 2017/2018 freezing season
Post by: Pavel on September 19, 2017, 10:38:33 PM
The Garlic Press still in action. Winds may change direction backward for some days but then it should resume. Ice was squeezing through the strait for the entire September not even depended on winds very much
Title: Re: The 2017/2018 freezing season
Post by: Brigantine on September 20, 2017, 12:12:01 AM
First sight on CIS daily charts of grey ice in the Eastern Arctic - in the Parry Channel around 102W.
(Approaches to Resolute 2019-09-19, areas D, G and M)

Also the first time in the Chukchi Sea that grey ice is forming in areas without surviving drift ice.
(Area D)

The new ice in Nares Strait and the Beaufort Tongue OTOH is struggling just to survive.
Title: Re: The 2017/2018 freezing season
Post by: Alec aka Daffy Duck on September 20, 2017, 10:37:32 PM
Hopefully this image comparing SST for Kara and Barents 2016 v 2017 will work:

(https://s19.postimg.org/7f2nx4c9f/aab_sst_2016_2017.png)

(https://postimg.org/image/k6gu3mm1b/)
<Alec, if you highlight the link, and then click on the img/image button (middle row, second from left, next to small f/flash button), the links will then show up as images. Or you can click 'attachment and other options' below the comment box and upload them to the Forum server directly; N.>
Title: Re: The 2017/2018 freezing season
Post by: Pavel on September 20, 2017, 11:32:51 PM
Hopefully this image comparing SST for Kara and Barents 2016 v 2017 will work:
https://s19.postimg.org/7f2nx4c9f/aab_sst_2016_2017.png
https://postimg.org/image/k6gu3mm1b/
Interesting that Hycom shows very warm currents north of Svalbard resume. North of Kara almost the only area relatively cold in terms o SSTs but it most likely should be hit by warm storms, it's not the area to build meters of ice. The Laptev sea that is the factory of ice for CAB looks warmer, ESS\Chukchi\Beaufort are terrible. The Hudson Bay and Sea of Okhotsk are overheated and promising low extent for the entire freezing season. Most likely we'll expierence the negative phase of the Arctic Oscillation
Title: Re: The 2017/2018 freezing season
Post by: Niall Dollard on September 21, 2017, 08:04:48 PM
Judging how, by eye, Thomas ? As to pronounce which is worst, I wouldn't wish to comment as brain/eye can be deceptive.
No, not really. It's pretty clear to a well trained eye. ;-)

So the PIOMAS half September figures are in and the min volume this year was 4.542 x 103 km3.

As Wipneus pointed out in the other thread, this is the 4th lowest min. The list being, in order of lowest:

3.673 (2012)
4.303 (2011)
4.402 (2016)
4.542 (2017)

2017 was close to 2016, but still an uptick in volume. Is this in line with what your well trained eyes was suggesting ?

From a PIOMAS volume POV, it is hardly the worst ever start to the freezing season. 
Title: Re: The 2017/2018 freezing season
Post by: Niall Dollard on September 21, 2017, 10:52:29 PM
The ECMWF shows some cooling on the Russian side over the weekend and early days of next week. If this comes to fruition we may finally see a bit of a move on the ice edge at the Russian side. Surface chart show temps circa -9 C between Severnaya Zemlya and New Siberian Islands. Temp at the 850hPa down to -18 C and then surface temps sub -9C for much of the week in that area.

At the end of the run, cold moves on down over the Chukchi but at the same time much warmer over Svalbard and the Atlantic side. So it is going to be give and take. 
Title: Re: The 2017/2018 freezing season
Post by: 2phil4u on September 22, 2017, 01:08:30 PM
Looking at dmi forecast you can see that the pacific side is still melting a bit, it will take maybe 2-3 weeks before we see big refreezes here.
In my opinion after this year we can see, that very often the effect of open ice in september in many years like last years may have a positive effect of next years ice.
Maybe the water just cools down more if it refreeze later.
So many years with catastrophic ice and regain the next year now.
Title: Re: The 2017/2018 freezing season
Post by: jdallen on September 23, 2017, 03:13:17 AM
Looking at dmi forecast you can see that the pacific side is still melting a bit, it will take maybe 2-3 weeks before we see big refreezes here.
In my opinion after this year we can see, that very often the effect of open ice in september in many years like last years may have a positive effect of next years ice.
Maybe the water just cools down more if it refreeze later.
So many years with catastrophic ice and regain the next year now.
South of 80N will refreeze more slowly, possibly not refreeze for quite a while.

Not sure if the heat loss will make up for the net increase in enthalpy.

We may see a lot of imported heat from cyclonic storms pulling moisture north from tropical and mid latitutdes.

That will slow heat loss from the Arctic.
Title: Re: The 2017/2018 freezing season
Post by: meddoc on September 23, 2017, 08:54:19 AM
Last Year massive Re- freeze only began by mid- December- according to HYCOM.
This Year should be no different, as Hycom is still showing Melt ongoing and Dispersion around the NP.
Title: Re: The 2017/2018 freezing season
Post by: gerontocrat on September 23, 2017, 01:14:36 PM
I know people have considerable reservations on the usefulness of the DMI 80+ N temperature graph. For observers such as me, at least it gives an idea of the direction of travel. At the moment, it suggests slow refreezing in the high Arctic.
Title: Re: The 2017/2018 freezing season
Post by: Pavel on September 23, 2017, 01:30:29 PM
Most of the survived ice stored north of 80 latitude. Since it relatively thick it needs more FDDs to grow. Freezing at open waters isn't happening yet. It should take quite while to strengthen the freezing momentum
Title: Re: The 2017/2018 freezing season
Post by: Niall Dollard on September 23, 2017, 02:24:54 PM
As said already with high SSTs and globally it being a warm year, arctic freezing is struggling.

Latest Eurasian snow cover image only shows snow at far north and sprinklings elsewhere. A decent Siberian snow cover would be beneficial to ice devlopment in the Laptev and ESS. When the large Siberain anticyclone develops even SW winds coming off the Asian land mass will be very cold. I think we would need something like a snow cover that would manage to fill the magenta coloured area below, over the next few weeks (October).

The changing Arctic climate is starting to produce more snow, but it remains to be seen whether there will be much progress this autumn.
Title: Re: The 2017/2018 freezing season
Post by: Dharma Rupa on September 23, 2017, 05:27:13 PM
Last year I thought this was an interesting diversion, but this year it is beginning to look like a trend:
Title: Re: The 2017/2018 freezing season
Post by: Dharma Rupa on September 23, 2017, 06:01:36 PM
I know people have considerable reservations on the usefulness of the DMI 80+ N temperature graph. For observers such as me, at least it gives an idea of the direction of travel. At the moment, it suggests slow refreezing in the high Arctic.

I'm perfectly fine with DMI 80N as a gross measure of what is going on.  I can understand why people might not like it when looking at the details, but it tells us rather directly that the big change in what is going on is happening in the Fall and Winter, not the Summer.
Title: Re: The 2017/2018 freezing season
Post by: Niall Dollard on September 23, 2017, 07:51:05 PM

I'm perfectly fine with DMI 80N as a gross measure of what is going on.  I can understand why people might not like it when looking at the details, but it tells us rather directly that the big change in what is going on is happening in the Fall and Winter, not the Summer.

What's going on in the autumn/fall and winter is a legacy of the summer conditions. It's all about the ice (or lack of it). Deviations on the DMI 80N are small in summer because we still have ice there (just about). However as we now move into autumn/winter we still only have a relatively small area of ice surrounded by warm seas. It's still easy enough to import milder air into the 80N circle. That's one of the reasons why the DMI graph starts to deviate so much from the norm at this time of the year.

If we had a blue ocean summer I'm sure the DMI graph would stray far away from norm too, in summer, once the ice is gone.
Title: Re: The 2017/2018 freezing season
Post by: bbr2314 on September 23, 2017, 08:13:09 PM
Snowcover should build very rapidly through early October. GFS/CMS/EURO all show a massive area of anomalously cold temps building across most of Eurasia by D10 corresponding to generous snowfalls across much of Siberia and the Central Asian Plateau. We will also see the first falls across much of Alaska, the NW Territories/Yukon, and Quebec, with possible lasting duration across the latter.

I think it is important to reflect on the divergent signals that have emerged at the same time over the past few years. Namely, Greenland is now *increasing* in ice mass, with albedo massively increased in year over year comparisons due to the tremendous and ongoing snowfalls that have been occurring. In fact I believe we have probably still seen the same or more melt than is normally seen, however, the sheer frequency of massive snowfalls has been sufficient (IMO) to overwhelm -- i.e., the same thing resulting in Houston's floods is now seemingly occurring up north in a format that is white and not wet. This at the same time that global sea ice is once again setting a record-low maximum...!

My suspicion is that this massively unexpected positive albedo trend over Greenland was directly responsible for the surprisingly meek melt season. In fact, it is the most obviously glaring unexpected happening of the past 12 months that it is quite likely to have been the cause.

The question is what happens moving forward? Snowcover is currently somewhat above average, that should increase to well above average as we move into October, both according to the models and as indicated by recent changing climatology. Besides Greenland's increase in mass, the Himalayas have also stayed overwhelmingly white through the summer. The combination of these albedo anomalies and the record-warm Arctic ocean waters should yield more opportunities for early season snowfall (IMO) and we may see record #s.

(https://www.tropicaltidbits.com/analysis/models/gfs/2017092312/gfs_asnow_asia_41.png)

(https://www.tropicaltidbits.com/analysis/models/gem/2017092312/gem_asnow_asia_40.png)

(https://www.tropicaltidbits.com/analysis/models/gfs/2017092312/gfs_T2ma_asia_36.png)
Title: Re: The 2017/2018 freezing season
Post by: Pavel on September 23, 2017, 08:21:18 PM
The MYI floats drift toward the Fram strait. The animation below is from 19 to 23 of September. From Hycom forecast the Fram export will resume finally
Title: Re: The 2017/2018 freezing season
Post by: Dharma Rupa on September 24, 2017, 02:46:11 PM
If we had a blue ocean summer I'm sure the DMI graph would stray far away from norm too, in summer, once the ice is gone.

I'm sure of that, but that will be in the future, not the present (and recent past).

Actually, the big change in DMI 80N happened in a single day in December 2015.  The question this winter is, will it continue for a third winter or revert to the norm -- and so far it's looking like it will continue.
Title: Re: The 2017/2018 freezing season
Post by: Niall Dollard on September 24, 2017, 06:24:34 PM

I'm sure of that, but that will be in the future, not the present (and recent past).

Actually, the big change in DMI 80N happened in a single day in December 2015.  The question this winter is, will it continue for a third winter or revert to the norm -- and so far it's looking like it will continue.

I see what you mean re Dec 2015. Around that time the big El Nino was in full swing. Global temp anomalies have remained high since.

Agreed there is little to indicate that we will have a different winter this time.
Title: Re: The 2017/2018 freezing season
Post by: A-Team on September 25, 2017, 11:48:36 AM
The UH AMSR2 site provides a very convenient one-click measure of open water in the Arctic Ocean for every day from August 2012 to the present. The first animation below looks at Sept 2012 relative to the minimum (for the month) on Sept 3rd and the melt-season maximum attained on Sept 12th.

The streaming numbers give the percentages of those days relative to those dates, minimum in the middle, maximum on the right. Open water has been mostly shrinking though on some days it increases. Reasons aren't determined by UH but could could include ice compaction, freeze, ridging and so on. The fixed gold line overlay shows the boundary of open water on the 12th.

The second animation takes the difference of each day relative to the 12th. The color scheme goes to 2D as the UH palette consists of 100 blues and whites, so subtraction results in a combinatoric palette, in effect what's called a bivariate chloropleth. Here the fixed open water boundary of the 12th is in light blue. The frame for the 12th is black from subtracting it from itself.

It is slightly more accurate to do the differencing earlier in the pipeline, from grid cells in the netCDF furnished by UH. That can be done in Panoply with the 'Combine Plot' feature that first subtracts the arrays grid cell by grid cell and only then draws the map in the chosen PS projection. (In Gimp, subtraction is done off the final map which is not quite equal area.) A still from grid subtraction is shown at the bottom in a red-blue diverging palette.

The third animation uses ten days of forecast data from RASM-ESRL concerning the compressive strength of the ice pack. Unsurprisingly, low concentration ice near the periphery is more compressible. While the units of that, newtons per meter, are not so intuitive, they measure how much the ice pack (considered as a viscous plastic) deforms in response to an applied force. These numbers range so widely that a logarithmic scale is more effective as palette animation. An inset shows shape change for the same dates in Hycom.

These animations can be made for any data range by scripting the download of netCDF data from a remote server (Fetch), opening a map in the desired palette and projection and saving out png frames (Panoply JavaScript) and cropping and layering up (Gimp batch). This just pipelines scientific visualization; the actual science went into processing satellite imagery and running the computationally intensive models that end up as the data archives.

The Arctic Ocean alone is the subject of 60-70 daily netCDFs describing the state of various physical parameters. Some of these are redundant, just using different satellites and algorithms for the same basic product, typically on different grids at different resolutions. Others are just input ingredients for models and don't overly concern us at the forums.

Validation of graphical products is complex. The data (like SMOS thin ice) may be more accurate in certain seasons than others; older published validations studies may not be applicable to New Arctic ice. Forecast 'skill' may be higher during stretches of really boring weather (summer 2017?) than during or after major wind events, significant on-edge wave heights, or moisture advection from the sout.

Some products like open water get 'reset' daily by easy-to-interpret satellite data, meaning models can't drift too far away from reality. Others like ice thickness or ice age get only partial resets in the fall as open water freezes to first year ice, allowing errors in older ice to accrue and persist.

Products concerned with long-term consistency and statistical trends are not likely to embrace new satellite technology (eg Sentinels) or integrate new hybrid methods because there's no way to go back to update earlier parts of the satellite record.

Below are three fairly recent studies on Arctic Ocean compressive strength and how it is measured.

Estimating the Sea Ice Compressive Strength from Satellite-Derived Sea Ice Drift and NCEP Reanalysis Data
LB Tremblay et al Nov 2006 free full text
http://journals.ametsoc.org/doi/pdf/10.1175/JPO2954.1+ (http://journals.ametsoc.org/doi/pdf/10.1175/JPO2954.1+)

On the mechanical behavior of compacted pack ice : A theoretical and numerical investigation
K Wang dissertation 2007
https://helda.helsinki.fi/handle/10138/23122 (https://helda.helsinki.fi/handle/10138/23122)

A younger, thinner Arctic ice cover: Increased potential for rapid, extensive sea-ice loss
JA Maslanik et al Dec 2007 free full text
http://onlinelibrary.wiley.com/doi/10.1029/2007GL032043/full (http://onlinelibrary.wiley.com/doi/10.1029/2007GL032043/full)
Title: Re: The 2017/2018 freezing season
Post by: Niall Dollard on September 25, 2017, 04:48:18 PM
ESRL Initial (2017-09-24 00Z) and 5 day forecast ice thickness.

Title: Re: The 2017/2018 freezing season
Post by: Daniel B. on September 25, 2017, 05:36:23 PM
Snowcover should build very rapidly through early October. GFS/CMS/EURO all show a massive area of anomalously cold temps building across most of Eurasia by D10 corresponding to generous snowfalls across much of Siberia and the Central Asian Plateau. We will also see the first falls across much of Alaska, the NW Territories/Yukon, and Quebec, with possible lasting duration across the latter.

I think it is important to reflect on the divergent signals that have emerged at the same time over the past few years. Namely, Greenland is now *increasing* in ice mass, with albedo massively increased in year over year comparisons due to the tremendous and ongoing snowfalls that have been occurring. In fact I believe we have probably still seen the same or more melt than is normally seen, however, the sheer frequency of massive snowfalls has been sufficient (IMO) to overwhelm -- i.e., the same thing resulting in Houston's floods is now seemingly occurring up north in a format that is white and not wet. This at the same time that global sea ice is once again setting a record-low maximum...!

My suspicion is that this massively unexpected positive albedo trend over Greenland was directly responsible for the surprisingly meek melt season. In fact, it is the most obviously glaring unexpected happening of the past 12 months that it is quite likely to have been the cause.

The question is what happens moving forward? Snowcover is currently somewhat above average, that should increase to well above average as we move into October, both according to the models and as indicated by recent changing climatology. Besides Greenland's increase in mass, the Himalayas have also stayed overwhelmingly white through the summer. The combination of these albedo anomalies and the record-warm Arctic ocean waters should yield more opportunities for early season snowfall (IMO) and we may see record #s.

The Western mountains of the U.S. has seen a swatch of snowfall also. 
Title: Re: The 2017/2018 freezing season
Post by: A-Team on September 25, 2017, 08:20:32 PM
Here is a nicely done HDF5 archive from NSIDC, sea ice concentration done now from microwave on the F18 satellite. The annotation is unusually thorough; to see it, download any date, open the file just like a netCDF and set the Source window view in Panoply to show all variables in the data set panel in enhanced mode.

Not being thrilled with 25 km x 25 km resolution sea ice concentration (while acknowledging the importance of such long-term records), I looked for other geolocated products (mappable in user's favorite projection and palette, designated as Geo2D in Panoply) in the HDF5 bundle.

There are two of interest, one called Melt Day Onset which seems to be a static file made in late spring 2017 and another called standard deviation of sea ice concentration which may be related to error assessment.

The former marks up ice pack locations according to the date when melt was first observed. That's of interest per se but only 2016 appears provided as a comparison year. This archive is something to be watched (along with ESRL's daily melt ponds) in spring 2018, presuming melt ponds are a helpful leading indicator for summer outcome.

The graphic below -- just the double-click default in Panoply -- shows Melt Day Onset in 'greenland down' stereographic projection in a sequential palette. It appears that the earliest melt recorded occurred on Day 60 but melt had been seen everywhere by Day 189. That latter date was presumably used for picturing the ice extent to be colored.

NSIDC may or may not have put a similar graphic somewhere on their vast web site. Note with the HDF file and Panoply, we can make a large colorful contoured map; however once past intrinsic data resolution that requires software interpolation which may not be physically meaningful.

The std dev we can make more simply in ImageJ off any sea ice product map (along with mean and variance filtering, for whole animation stacks too) but it's better to work from original girdded numeric data. Note here Panoply can export HDF5 data into human-readable form (the CDL option), though a lot of people here use the R statistical package which can read these files directly (package 'ncdf4'). Climate data can have lots of data hole, stored as NaN grid cell entries for Not a Number, which ImageJ can map out.

People may recall the endless hubbub over the 'hockey stick' graphic, it being claimed (wrongly) height and width scales were deliberately chosen to be misleading. However there is something to be said for seeking accuracy in scientific visualizations, or rather helping the viewer form an accurate impressions.

While there's been endless hubbub bashing rainbow palettes, misleading for a prevalent retinopathy in white males, there's been little discussion of palette optimization in rapid-fire gif animations. Over in that section of Dev Corner, there'll also be discussion of 'adaptive' palettes which are not aesthetic choices but rather objectively driven by 2D statistical properties of the data itself.

Note here that 'Integral Image Filters' over at ImageJ allows analysis and suppression of data outliers as well as various radial map statistics. The former allows objective setting of palette range which is very important to equalizing palette color usage and viewer feature discrimination. The latter show variation by distance out from a given pixel which could be useful in optimizing the  number of palette colors, avoiding maps that are too 'busy' to be contoured, etc.

ftp://sidads.colorado.edu/pub/DATASETS/NOAA/G10016/north/daily/2017/
Title: Re: The 2017/2018 freezing season
Post by: Neven on September 25, 2017, 10:56:59 PM
There are two of interest, one called Melt Day Onset which seems to be a static file made in late spring 2017 and another called standard deviation of sea ice concentration which may be related to error assessment.

The former marks up ice pack locations according to the date when melt was first observed. That's of interest per se but only 2016 appears provided as a comparison year. This archive is something to be watched (along with ESRL's daily melt ponds) in spring 2018, presuming melt ponds are a helpful leading indicator for summer outcome.

This might be part of research involving Julienne Stroeve as a co-author (found it: 2016 Mortin et al. (http://onlinelibrary.wiley.com/doi/10.1002/2016GL069330/abstract)). I asked her if she could keep me informed on when melt onset was happening and how it related to previous years a couple of times, but she's very busy, of course.

It would be great to have this kind of info at our disposal. As I've understood it, melt onset doesn't mean melt ponds will form right away, but it does precondition the snow on the ice, so that when solar radiation comes into play, melt ponds may form faster. This preconditioning mostly takes place when it's cloudy!
Title: Re: The 2017/2018 freezing season
Post by: A-Team on September 25, 2017, 11:08:17 PM
Oren mentioned a quick way to make animations a while back: just make a list of the urls needed and ask ImageJ to make Stack from List, crop as needed, export at the animation speed wished, load to forum. That works well for ESRL graphics of the current day using the attached list for their fig.3 (grep to something else if needed),

Their model is seeing very little net melt the next few days. The winds, pressure temperatures are not notable above Svalbard for the next few days considering sea water at the exposed salinity freezes at about -1.8ºC (if not mixed or agitated).

Nullschool animations are most easily made saving whole-window screenshots to Gimp while scrolling through the forecast with shift-k. After image duplication, the text annotations can be cut out, made smaller, and layered over the tiled-up resized crop of the Arctic Ocean prior to flattening, slicing into frames and saving those layers as a forum animation.
Title: Re: The 2017/2018 freezing season
Post by: A-Team on September 25, 2017, 11:32:27 PM
Quote
This might be part of research involving Julienne Stroeve as a co-author  ... she's very busy, of course. great to have this kind of info ... melt onset doesn't mean melt ponds will form right away, but it does precondition the snow on the ice, so that when solar radiation comes into play, melt ponds may form faster.   mostly takes place when it's cloudy!
Right all around. Clouds can have counter-intuitive effects in the off-season. It is really an upwelling versus downwelling radiation balance story where common sense can flatline into not even wrong. ESRL has some good-looking daily products in that department that we should do more with. Even if not spot-on, they're physically based and the only thing currently out there; by playing with those, we'd be ready if something more accurate comes along.

Stroeve is maybe still on sabbatical in London? She was a PI on that fancy plane landing transect above Alert too, the best thing going for snow samples and real ice thickness. She is listed in the melt date HDF5 above along with:

:contributor_name = "Walt Meier, Ruth Duerr, Florence Fetterer, Julienne Stroeve, Matt Savoie, Sean Mallory";
:contributor_role = "PrincipalInvestigator,author,author,author,author,author";
Title: Re: The 2017/2018 freezing season
Post by: Niall Dollard on September 26, 2017, 12:11:13 AM
Quick, one year round the sun, snapshots of the US NIC snow and ice charts. (Only 2d of course).

Not much difference really in coverage between the 2 years. But difference in ice location. Back in 2016 we had the Wrangel Arm, this year the East Beaufort Tongue. Both years show a bite above the ESS which was more pronounced in 2016. Ice edge is a little more south at the top of Kara Sea in 2017.

On first viewing you would think the late Sept 2016 ice was making some early progress towards the Chukchi - but as we know subsequently, max ice development on the Pacific side was very low in the end.

 
Title: Re: The 2017/2018 freezing season
Post by: Pavel on September 26, 2017, 12:15:36 AM
Interesting pattern of the Jet stream is going to set in several days on September 30. The wave from subtropics to the North Pole through the Greenland. Brings more heat to the Arctic, cold anomalies in Syberia and Greenland ice sheet growth
Title: Re: The 2017/2018 freezing season
Post by: jai mitchell on September 26, 2017, 03:21:14 AM
Excellent summary of the 2017 season here:https://news.mongabay.com/2017/09/at-2017-minimum-scientists-ask-is-arctic-entering-the-thin-ice-age/
Title: Re: The 2017/2018 freezing season
Post by: Sterks on September 26, 2017, 08:55:50 AM
Starting to get less and less interested on stories that fall on the side of greatest drama. Like a bell I have been hearing for years and is not alarming or thrilling anymore, but a bit bothering.
What about "Volume rebounds 2000 km3 from spring, but statisticaly continues its downward trend just as area and extent do"
Maybe  "A relatively cold spring and summer at high latitudes helps the Arctic end in slightly better conditions than 2016 and 2015"
Or perhaps "The least drama side (or cold-facts side) of several scientists expecting seasonally ice-free Arctic by somewhere mid-century, while not dramatic, may have some base after all"
The last one is an inconvenient statement for some with apocalyptic thoughts who want to see the blue Arctic in their lifetimes  ;) preferably next year.
Title: Re: The 2017/2018 freezing season
Post by: Neven on September 26, 2017, 09:59:01 AM
Starting to get less and less interested on stories that fall on the side of greatest drama. Like a bell I have been hearing for years and is not alarming or thrilling anymore, but a bit bothering.
What about "Volume rebounds 2000 km3 from spring, but statisticaly continues its downward trend just as area and extent do"
Maybe  "A relatively cold spring and summer at high latitudes helps the Arctic end in slightly better conditions than 2016 and 2015"
Or perhaps "The least drama side (or cold-facts side) of several scientists expecting seasonally ice-free Arctic by somewhere mid-century, while not dramatic, may have some base after all"
The last one is an inconvenient statement for some with apocalyptic thoughts who want to see the blue Arctic in their lifetimes  ;) preferably next year.

Because the consequences of Arctic sea ice loss do not start once the Arctic is practically ice-free. They have already started, we don't know what the impacts will be exactly, and so, as long as things do not show any signs of returning to the pre-2005 mean (at the very least), the drama is great.

A seasonally ice-free Arctic by somewhere mid-century is dramatic. At the end of the century is dramatic. Do you have any idea how fast that is on geological time scales?
Title: Re: The 2017/2018 freezing season
Post by: gerontocrat on September 26, 2017, 12:04:00 PM
Having had my daily dose of NHC.NOAA.GOV and looked at weather-forecast.com, methinks there is a chance of stormy weather arriving in the Arctic next week. Specifically, remnants of Lee in about 7+ days and Maria in 9+ days ?
Much depends on the persistence or otherwise of the high over NW Europe currently sending Atlantic lows North instead of hitting the UK.

Just looked at Pavel's post above re jet stream. This should increase chance of Lee/Maria remnants arrival in the Arctic happening?
Title: Re: The 2017 freezing season
Post by: meddoc on September 26, 2017, 01:19:04 PM
Yesterday snowfalls in some parts of Siberia are month earlier than usual. Snow depth in north-west Yakutia is 10cm what is the biggest ever for 27 of August, according to a russian wheather TV

The Arctic Refridgerator Door is open, still. And will only get worse.
Title: Re: The 2017/2018 freezing season
Post by: A-Team on September 26, 2017, 01:24:20 PM
Quote
the consequences of Arctic sea ice loss do not start once the Arctic is practically ice-free. They have started already ... seasonally ice-free Arctic mid-century
The perennial confusion on the forums over what 'seasonally ice-free' means allows just about any futuristic belief system to flourish.

If you think there there must be a perfect low albedo match between open water and a cloud-free peak solar isolation season (6 weeks on each side of on the June 21st solstice) for it to 'count', that's a long ways off because melt hardly gets underway in early May now and doesn't peak until mid-September. Thermal lag isn't going away any time soon.

If you think there there must be a fairly good match between open water in regional seas and peak isolation for it to 'count', that's already here for the peripheral seas such as Chukchi, Barents, Beaufort, Bering, ESS, Laptev. The Chukchi did not freeze over until mid-December 2016, opened already in early June 2017 and has been totally ice-free now for months.

If you think that Arctic amplification of global warming is all about albedo, you're completely wrong. It's primarily a fall and winter effect of clouds and radiation imbalance over reduced sea ice. And what's happening in the Arctic today isn't staying in the Arctic.

The animations below revisit SMOS, the preferred satellite instrument for measuring thin ice (less than a meter thick). UH considers it fairly worthless in melt season and stops updating their image archive in mid-April. They've got a new paper out on it however, https://www.the-cryosphere.net/11/1607/2017/tc-11-1607-2017.pdf (https://www.the-cryosphere.net/11/1607/2017/tc-11-1607-2017.pdf)

Meanwhile UB continues to post their daily thin ice report. The first 25 days of this month are shown below, along with a comparison to UH sea ice concentration for the 25th. UB is showing a lot of thin ice poleward of Wrangel whereas AMSR2 has somewhat reduced ice concentration. Only ice less than 0.5 m is colored according to the legend. SMOS isn't able to locate 0.5 to 1.0 m ice this time of year. The agreement with ESRL ice thickness isn't stellar.

UB SMOS might also be worth comparing later on to ESRL thickness products which do not use this satellite. However, while UH provides their netCDF files, UB does not. That, plus a very small UB graphic in a peculiar color scheme, puts quantitative comparison with ESRL out of reach.
Title: Re: The 2017/2018 freezing season
Post by: Thomas Barlow on September 26, 2017, 03:19:05 PM
Starting to get less and less interested on stories that fall on the side of greatest drama. Like a bell I have been hearing for years and is not alarming or thrilling anymore, but a bit bothering.
What about "Volume rebounds 2000 km3 from spring, but statisticaly continues its downward trend just as area and extent do"
Maybe  "A relatively cold spring and summer at high latitudes helps the Arctic end in slightly better conditions than 2016 and 2015"
Or perhaps "The least drama side (or cold-facts side) of several scientists expecting seasonally ice-free Arctic by somewhere mid-century, while not dramatic, may have some base after all"
The last one is an inconvenient statement for some with apocalyptic thoughts who want to see the blue Arctic in their lifetimes  ;) preferably next year.
With all due respect, I may have misread you, but I think you are looking at it in a very black and white way: Ie. "Is it at the lowest, or is it not?", as are many people on the internet today.
I'm sorry, but that is just a very primitive way to think about the Arctic.

First off, to me (and I think this is what Wadhams thinks too based on e-mails and knowing how old Oxford boffins from a bygone era, tend to talk), is that a "Blue Ocean Event" doesn't really mean a full blown open ocean like the Mediterranean or something. It means a ton of icebergs floating around all over the place, with enough room to sail ships through them in most places, and a load of ice clinging to land masses.
ie. Icebergs everywhere, but no discernible (or very small) "ice-pack". Huge portions of the Arctic Ocean were getting close to that this year.

The Arctic Ocean itself is close to, or at, the worst shape (volume) on record, apart from thick ice crushed against land-masses. And this is the answer you should give to climate-science deniers who are all over the Net now, braying about how the "Arctic is growing".

North Atlantic waters seeping into the Arctic are warmer than ever, the Nares was open all year since last year, the SSTs all around are warmer, the overall Arctic Ocean volume (ignoring thick ice crushed against land) is close to the worst state on record at start of freezing season, if not the worst, the ice itself is said to be poor quality, the fire seasons are pouring more soot over the Arctic than ever, and the fire seasons are longer than before, the seabeds are thawing, the tundra is warming.

I try really hard to see the good news, and the idea that 'we dodged a bullet' being floated all over the internet now. I don't see it. “Extent” is not telling the true state the overall Arctic Ocean.
These general extent graphs are deceptive. I do think volume is the most important factor, and that volume in the overall Arctic Ocean to be the most important indicator. There could be more snow in winter, but that's about it (which is what climate-scientists predicted for decades now).

So "dodging a bullet",  or "7th worst on record", it is not.
But wait for the science-deniers across the right-wing news to start shouting that ""the Arctic ice is in the best shape in years, and getting better.""

I am very concerned that ice-aficionados are going to let the climate-science-deniers get away with it, because these ice-observers themselves are saying "things are not that bad, because extent (of sea-ice in the N. Hemisphere) is better than expected". I think it's dangerous, and neglectful.

(I know this is largely OT, just responding to what may be an OT comment - could put it somewhere else.)
.
Title: Re: The 2017/2018 freezing season
Post by: Niall Dollard on September 26, 2017, 05:10:18 PM
I am very concerned that ice-aficionados are going to let the climate-science-deniers get away with it, because these ice-observers themselves are saying "things are not that bad, because extent (of sea-ice in the N. Hemisphere) is better than expected". I think it's dangerous, and neglectful.

(I know this is largely OT, just responding to what may be an OT comment - could put it somewhere else.)
.

I was wondering about the general focus from some of your previous posts, Thomas. Particularly in relation to comparing this year to previous. I have always assumed that the ASI Forum members are all pretty well knowledgeable folk and understand many of the intricacies and importance of the Arctic Sea Ice. I didn't think that deniers would ever be really interested in this forum, that is bar the odd troll.

So unless I am way off track here, I think we are all on the same hymn sheet and have great concern for the Arctic.

In your paragraph quoted, I believe you have explained the reasons for, let's say your extra sensitivity. Complacency. It is a valid point. We would not want to give any impression to others outside of this forum that the Arctic is somehow turning a corner.

However inside the forum I would hope that members here are free to highlight discuss debate the intricacies of the ice. Good or bad. If I make a comment that volume is gone up - it is no way intended as to give a boost to the deniers. There are plenty of places on the net where they can gather their spurious facts - I doubt if they are bothered about what you or I are saying.

I would be concerned that healthy discussion would be limited if we all had to hold our tongue typing for fear that we are somehow letting the side down.

But I doubt if anyone on here is being complacent. There are things I would say here for example that I would be careful saying outside of this forum.
Title: Re: The 2017/2018 freezing season
Post by: Thomas Barlow on September 26, 2017, 06:09:57 PM
I am very concerned that ice-aficionados are going to let the climate-science-deniers get away with it, because these ice-observers themselves are saying "things are not that bad, because extent (of sea-ice in the N. Hemisphere) is better than expected". I think it's dangerous, and neglectful.
Quote
I didn't think that deniers would ever be really interested in this forum, that is bar the odd troll.
So unless I am way off track here, I think we are all on the same hymn sheet and have great concern for the Arctic.

Yes, you are WAY off track to what I posted.
Try again. Go back, read it again, without prejudice. It's English, so if English is your second language, I'm sorry, let me know and I will re-explain it.
I said NOTHNG about people here having to hold their tongue. Your prejudice is palpable, and you are wasting cyber-space with erroneous interpretations.

And why didn't you pick up on HIS statements about people on this forum? : eg. ""The last one is an inconvenient statement for some with apocalyptic thoughts who want to see the blue Arctic in their lifetimes ;-) preferably next year."" His whole post was a critique/smear of people on this forum (not of me, because I am not a doomer, but a rationalist). whereas mine wasn't. His was CLEARLY a veiled comment on some people's doomerism here. There's nothing really wrong with his comment by the way (except that it seems OT to me), and it stimulates conversation - about the topic at hand, not whole posts about personality judgements, as yours is -  but you deciding that I am  the one 'gaslighting' instead of the other, is just you projecting your own prejudices, and wasting space.

Unless English is your second language, in which case I apologize.

Stop wasting space with personality attacks, and deal with the substance of my post. You are just deflecting from the discussion and substance of the post with these  personality cliques.

(If you delete your post, I'll delete this one, because this personality BS is a waste of space. You can try critiquing the substance of my post instead - about the Arctic. Maybe it needs the be on a different thread though. This is 'The 2017 Freezing Season', not some place to critique people's concerns or lack thereof about the Arctic, as Sterks started with. I'm quite happy to have this discussion moved elsewhere. Deal with the substance of my post next time.)
Title: Re: The 2017/2018 freezing season
Post by: gerontocrat on September 26, 2017, 06:41:41 PM
I look at this thread for data.
Title: Re: The 2017/2018 freezing season
Post by: Forest Dweller on September 26, 2017, 08:59:07 PM
The perennial confusion on the forums over what 'seasonally ice-free' means allows just about any futuristic belief system to flourish.

If you think there there must be a perfect low albedo match between open water and a cloud-free peak solar isolation season (6 weeks on each side of on the June 21st solstice) for it to 'count', that's a long ways off because melt hardly gets underway in early May now and doesn't peak until mid-September. Thermal lag isn't going away any time soon.

If you think there there must be a fairly good match between open water in regional seas and peak isolation for it to 'count', that's already here for the peripheral seas such as Chukchi, Barents, Beaufort, Bering, ESS, Laptev. The Chukchi did not freeze over until mid-December 2016, opened already in early June 2017 and has been totally ice-free now for months.

If you think that Arctic amplification of global warming is all about albedo, you're completely wrong. It's primarily a fall and winter effect of clouds and radiation imbalance over reduced sea ice. And what's happening in the Arctic today isn't staying in the Arctic.

The animations below revisit SMOS, the preferred satellite instrument for measuring thin ice (less than a meter thick). UH considers it fairly worthless in melt season and stops updating their image archive in mid-April. They've got a new paper out on it however, https://www.the-cryosphere.net/11/1607/2017/tc-11-1607-2017.pdf (https://www.the-cryosphere.net/11/1607/2017/tc-11-1607-2017.pdf)

Meanwhile UB continues to post their daily thin ice report. The first 25 days of this month are shown below, along with a comparison to UH sea ice concentration for the 25th. UB is showing a lot of thin ice poleward of Wrangel whereas AMSR2 has somewhat reduced ice concentration. Only ice less than 0.5 m is colored according to the legend. SMOS isn't able to locate 0.5 to 1.0 m ice this time of year. The agreement with ESRL ice thickness isn't stellar.

UB SMOS might also be worth comparing later on to ESRL thickness products which do not use this satellite. However, while UH provides their netCDF files, UB does not. That, plus a very small UB graphic in a peculiar color scheme, puts quantitative comparison with ESRL out of reach.
[/quote]

Thank you A-Team,

that explains some things even to a novice like myself.
Any thoughts on that polyanna which seems quite big?
Or is that a regular pehenomenon?
Title: Re: The 2017/2018 freezing season
Post by: Neven on September 26, 2017, 10:21:50 PM
I look at this thread for data.

I apologize, I should've (re)moved Sterks' comment, instead of replying to it.
Title: Re: The 2017/2018 freezing season
Post by: Sterks on September 26, 2017, 11:07:04 PM
Yes, Neven, removable, OT, but there was a Jai Mitchell's off topic just above mine to which I reacted. As I would have, if the headline he was bringing had been ""the Arctic ice is in the best shape in years, and getting better".
All the same, letting politics and/or interests one side or other twist the truth or plainly lie.
Back to topic.
Title: Re: The 2017/2018 freezing season
Post by: A-Team on September 27, 2017, 12:05:24 AM
Quote
FD asks: Any thoughts on what caused that big polynya this year? Or is it a regular phenomenon?
Its origin and persistence remain a mystery but it finally appears to be getting sheared apart. We put our heads together on causation but nothing persuasive ever surfaced that made physical sense for that location.

A look-back for 2012-17, displayed as a CW hexagonal kaleidoscopic animation below, indicates polynyas developed at a similar (but not identical) location in some but not all years, unhelpful. I meant to email a Russian scientist who specializes in that region's ice for comment but never got to it. We'll have to get back on it if it re-forms again in 2018.

Origin and persistence should probably be separated. The ice pack, viewed from far way, deforms somewhat like bread dough. Just as the hole in a doughnut survives on a hockey rink despite getting knocked around, once formed, the polynya could be somewhat protected by rigid ice around it.

The 2017 summer melt season saw very little change weather patterns or ice pack movement. The staples of Arctic ice motion -- Beaufort Gyre, Transpolar Drift, Fram export, Nares export and CAA garlic press -- were basically inoperative. The bottom animation shows the polynya over the 18-26 Sep 17 time frame. Strong CCW rotational shear can be seen on the 22nd and 23rd, presumably from the low pressure system discussed up-forum.

The origin: who knows, maybe there was a week there with a break in the clouds. Happenstance with no deeper meaning is the null hypothesis and it is not easy to find grounds to reject it.

See https://forum.arctic-sea-ice.net/index.php/topic,1834.msg125949.html#msg125949 for more discussion and imagery.

(https://forum.arctic-sea-ice.net/index.php?action=dlattach;topic=1834.0;attach=50584;image)
Title: Re: The 2017/2018 freezing season
Post by: Pavel on September 27, 2017, 10:32:04 AM
Cold anomalies in Siberia and the Laptev sea cools quickly. I was expecting slow freeze up of the Laptev but now it looks it will freeze like in previus years. Chuckchi and ESS still look terrible, that may lead to low November SIE but we'll see
Title: Re: The 2017/2018 freezing season
Post by: Niall Dollard on September 28, 2017, 12:05:12 AM
We had two 100K AMSR2 Area gains in the past two days, finally getting a bit of freezing momentum going. Much of it was from the Russian side. Currently air surface temps there are circa -10 C near the ice edge.

Teasing through today's ECMWF 12Z surface temp forecast for the Arctic, shows that cold will hold for a while yet near the Russian edge. But warm southerlies will be moving north over Svalbard to the Pole.

This anticyclonic ridge over the Pole sinks slowly south and east. By the end of the run (out to end first week October) the anticyclone is now centred in a more typical Siberian position. The Arctic on the Russian side will have lost its cold surface conditions at that stage - which should put a slow down then on ice development.

Meanwhile the American side becomes more dominated by low pressure (by end of run pressure falls over much of Arctic Basin).  Some cold temps and likely ice expansion through the CAA then next week and later into the Beaufort. Nothing much to be expected from the Atlantic side (more in retreat mode). Chukchi is very slow this autumn.

 
Title: Re: The 2017/2018 freezing season
Post by: A-Team on September 28, 2017, 12:57:53 AM
Here is the next ten days of surface temperatures of the Arctic ice pack itself, not the air. The animation of ESRL 6 hr x 10 day forecast uses the orthographic projection (view from space) as described in the new PanoplyCL javascript manual. This shows the earth rotating with its sun shadow as the colors change for the surface temp as time precedes.

The Arctic Ocean is too small for the whole-globe view to be effective. It may be feasible however to fill in the northern oceans with nullschool weather displays as its orthographic settings can easily be set to match those of PanoplyCL.

Here the viewpoint is directly above an initial lat,lon. In this instance, the first frame is directly below Little Diomede in the Bering Strait (65.7º, -168.9) but it worked better to drop down to 45º,-170º and hold the latitude fixed while longitude was incremented by 360º/40 ESRL frames = 9º per time series advance.

That series of lat,lon can be replicated in calling up the corresponding view in nullschool's Earth. Those are set in the url. However Earth uses a 3rd scaling parameter (zoom or height of the view above the surface); its correspondence needs to be established with the 'Visible Radius' parameter of PanoplyCL which is 90º below.

Because PanoplyCL makes clean colored maps (fixed palette, no dithering) whereas nullschool does not, the overlay is best done by removing land and water from the Panoply display, letting nullschool display show through for non-ice regions (still image below).

Once all the ducks are in a row, the whole animation just takes 2-3 clicks of the mouse to make  and load onto the forum.

Title: Re: The 2017/2018 freezing season
Post by: slow wing on September 28, 2017, 01:22:38 AM
  A-Team, thanks for your (typically) wonderful graphics above #118 (https://forum.arctic-sea-ice.net/index.php/topic,2141.msg130021.html#msg130021) concerning the persistent hole observed this year in the ice north of the Laptev Sea.

  You conclude "Happenstance with no deeper meaning is the null hypothesis" and say there is no reason to reject it.

  Your graphics show, as you say "polynyas developed at a similar (but not identical) location in some but not all years" from 2012 onwards. In my view that would be surprising under the null hypothesis. The persistence of the 2017 hole was already surprising to me.

  While I agree the null hypothesis cannot yet be rejected, in my view there are other hypotheses that are reasonable and worth exploring further.

  In particular, the polynya was over the Gakkel Ridge - a prominent baryometric feature and with known geothermal vents.

  An issue that needs to be addressed here is that underwater volcanism has been abused by some as a counter to climate change concerns. Here is an example where a polynya was observed over the Gakkel Ridge and all sorts of non sequiturs were drawn from that: http://climatechangedispatch.com/heat-from-deep-ocean-fault-punches-hole-in-arctic-ice-sheet/ (http://climatechangedispatch.com/heat-from-deep-ocean-fault-punches-hole-in-arctic-ice-sheet/).

  The intuition of some climate scientists has been that the volcanism probably doesn't have much affect on the sea ice: https://dotearth.blogs.nytimes.com/2008/07/01/whats-up-with-volcanoes-under-arctic-sea-ice/. (https://dotearth.blogs.nytimes.com/2008/07/01/whats-up-with-volcanoes-under-arctic-sea-ice/.)

  However, that seems somewhat equivocal. The argument is that the heat certainly effects the local ocean depths but is diluted before it gets to the surface.

  The amount of volcanic heat averaged over the Arctic basin is said to be of order 0.1 W/m^2. As it takes around 334 kJ/ kg to melt ice, that is about enough to melt around 3 mm of ice over 4 months (10^7 seconds), averaged over the Arctic basin.

   But what if much of the heat from the Gakkel Ridge volcanoes effectively reaches the surface over the much smaller region where the polynya formed? That much heat over ~1/300th of the Arctic Basin (say 20,000 km^2 which, eye-balling, looks of order the size of the polynya) could melt of order an extra metre of ice rather than just 3 mm and so could punch a polynya in the ice.

  To me the polynya was a notable and recurring feature and some sort of mechanism for getting volcanic vent heat to the surface to cause that is not ruled out as far as I know.

   Are there measured temperature and salinity profiles in that region? (I seem to recall there being a string of Russian tethered buoys but that may be closer to shore.)

UPDATE: there is some instrumentation, see http://research.iarc.uaf.edu/NABOS2/technology.php (http://research.iarc.uaf.edu/NABOS2/technology.php):
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fresearch.iarc.uaf.edu%2FNABOS2%2Fpics%2Ftechnology%2Ffigure1.jpg&hash=ba85a9260851ab0bc98457da1b1869fe)
Title: Re: The 2017/2018 freezing season
Post by: Rob Dekker on September 28, 2017, 04:29:32 AM
If you think there there must be a perfect low albedo match between open water and a cloud-free peak solar isolation season (6 weeks on each side of on the June 21st solstice) for it to 'count', that's a long ways off because melt hardly gets underway in early May now and doesn't peak until mid-September. Thermal lag isn't going away any time soon.

While I don't think anyone claimed that there must be a perfect low albedo match between open water and a cloud-free peak solar isolation season, PIOMAS does seem to suggest that the highest rate of melt is around summer solstice (June 21) :

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fneven1.typepad.com%2F.a%2F6a0133f03a1e37970b01b7c91dd148970b-pi&hash=54a80bb85c6a7ff4398947a18cef2d87)

So while it may intuitively feel like thermal lag should be a major player, volume development suggests that ice melt is mostly dominated directly by insolation, especially during recent years.
Title: Re: The 2017/2018 freezing season
Post by: Niall Dollard on September 28, 2017, 09:27:16 AM
Here is the next ten days of surface temperatures of the Arctic ice pack itself, not the air.

Yes. Nice animation. It concurs very much with the ECMWF, showing the pack warming right up the middle of the Arctic, the colder temps leaving the Russian side and a cold plunge through the CAA.

If the forecast holds through, the conditions by Oct 7 are mild over much of the Arctic and we could see freezing plateau for a time, at that stage.
Title: Re: The 2017/2018 freezing season
Post by: A-Team on September 28, 2017, 02:31:10 PM
Quote
mild stretch coming
Good. Unlike windyty, we don't have the ECMWF option available for ESRL or nullschool. Here is that same data for surface temperature of the ice pack, now in polar stereographic. The forum at first refused to load it, claiming an ordinary gif "failed security checks, contact admin" but now it seems to pass muster.

Quote
peak rate of volume loss
That would be the slope (first derivative) of the Piomas volume graphs. Since that is determined primarily as a first-of-the-month monthly average, those graphs are curve-fit to a very sparse set of points, only 3-4, so the nuances are illusory. As the graph stands, the rate of volume loss is flat (2nd derivative indistinguishable from zero) for most of the summer. Some products have seasonally varying error (for example SMOS thin ice thickness) which complicates assessment.

People do not swim much in Lake Superior in June. Mid-August, yes.

Quote
UPDATE: there is some instrumentation, see http://research.iarc.uaf.edu/NABOS2/technology.php: (http://research.iarc.uaf.edu/NABOS2/technology.php:)
Thanks for relocating that. Those would be the people to ask about the persistent polynya. The late Sept view is updated through the 27th below. It would be most impressive if the polynya were able to restore itself after days of significant shear and translation.

The only documented Gaekel Ridge volcanism is a good thousand km away where it is widening much faster; short-lived magmatic events at 4000 m depth cannot plausibly bring thermal upwelling to the surface. You can see that just from the minimal effect of Kilauea Iki lava flow into the ocean on youtube. It skins over quickly, forming a barrier to diffusive heat flow. The energy is just not there to heat cubic kms of very cold water fast enough, a density gradient would dissipate rapidly via other processes.
Title: Re: The 2017/2018 freezing season
Post by: oren on September 28, 2017, 03:32:58 PM
Quote
peak rate of volume loss
That would be the slope (first derivative) of the Piomas volume graphs. Since that is determined primarily as a first-of-the-month monthly average, those graphs are curve-fit to a very sparse set of points, only 3-4, so the nuances are illusory. As the graph stands, the rate of volume loss is flat (2nd derivative indistinguishable from zero) for most of the summer.
I believe Wipneus plots his PIOMAS graph from the daily PIOMAS data, not from the monthly, and from my experience with the data there are differences in slopes during the month. Of course it doesn't change the fact that the smoothed 2nd derivative is near zero during most summers.
Title: Re: The 2017/2018 freezing season
Post by: A-Team on September 28, 2017, 03:55:29 PM
The daily is not available for earlier years, even though smooth graph lines are shown for them. Only recently have we gotten mid-month. Wip wrote at one point the daily was too noisy to work with. (This could be quantitated statistically by variance etc. but that hasn't surfaced.) Some sort of smoothing, like a rolling window, may have been applied. The algorithm is effective volume averaged over grid cells. This doesn't really show on the daily animation of the month because the grid cell is far too sparse.

It would be very difficult to take derivatives on this sort of data as error analysis would be very central to that. To compare derivatives at specific dates by subtraction of very similar numbers at a statistically significant level brings in another whole new array of problems.

While ESRL only serves volume implicitly as a thickness grid (only from 15 Aug 17 on), anyone here could javascript the daily differences using a stock manual script and default 'Combine Plot' which is subtraction. It's unusual though for good things to emerge from subtracting two large numbers that are very similar, so it might be better to try weekly.

But even that runs afoul of the very small change in thicknesses involved relative to model precision. You can see that just by watching minimalist squiggles in the zonal average plot (area-under-the-curve is effectively volume, after adjusting to the number of cells). The animation is edge-cropped so volume measurement and its change are just a single click with a contiguous color pixel counter (available in any post-1998 imaging software). But just from comparing the change from first to last frame (10 days), daily differencing will prove delusional (2nd image). It's asking too much of a model. There's better action watching paint dry.

No one has been able to get Piomas out of its funky format into standard climate science formats like geolocated gridded HDF5 (or at least there seems no online archive of it). That would enable easy comparisons with other estimates of daily volume and indeed that is a primary purpose of these formats.

In the larger picture of global climate change, there's no central archive, so computers crawl the internet to find machine-readable data for maybe 25-30 variables to collect the input for to run ever increasingly complex models. It is unworkable to have every archive using a different ad hoc storage scheme. That's silo science; we don't have time for that anymore.
Title: Re: The 2017/2018 freezing season
Post by: Blizzard92 on September 28, 2017, 05:43:21 PM
Hi all,

As we are now moving forward into the freeze season, I have updated my FDD monitoring plots for 2017-2018 at http://sites.uci.edu/zlabe/arctic-temperatures/ (http://sites.uci.edu/zlabe/arctic-temperatures/)
Title: Re: The 2017/2018 freezing season
Post by: Shared Humanity on September 28, 2017, 05:59:37 PM
Hi all,

As we are now moving forward into the freeze season, I have updated my FDD monitoring plots for 2017-2018 at http://sites.uci.edu/zlabe/arctic-temperatures/ (http://sites.uci.edu/zlabe/arctic-temperatures/)

Time will tell but it would appear that 2017 is tracking with 2016.
Title: Re: The 2017/2018 freezing season
Post by: Daniel B. on September 28, 2017, 06:28:01 PM
Hi all,

As we are now moving forward into the freeze season, I have updated my FDD monitoring plots for 2017-2018 at http://sites.uci.edu/zlabe/arctic-temperatures/ (http://sites.uci.edu/zlabe/arctic-temperatures/)

Time will tell but it would appear that 2017 is tracking with 2016.

To early to make too much of a pronouncement.  One could also say that it is tracking with 2015 or 2011.
Title: Re: The 2017/2018 freezing season
Post by: Ice Shieldz on September 29, 2017, 04:18:03 AM
A-Team:

Quote
"It is unworkable to have every archive using a different ad hoc storage scheme. That's silo science; we don't have time for that anymore."

Absolutely, that is the most salient truth in all this, and to my understanding it's a key reason why ASIF exists. So thank you for all your work in reaching across the silos and bringing the science together in a visual and accessible way- especially now when we need it most!
Title: Re: The 2017/2018 freezing season
Post by: A-Team on September 29, 2017, 09:52:47 PM
Quote
bringing the science together in a visual and accessible way
What I am doing, one-off prototyping, is not really sustainable. The real excitement is over at Dev Corner where Dryland is building a master controller that can inject data sources into sequential scripts of retrieval, html templating, Panoply, ImageMagick, gimp, ncgen and others.

When there is massive daily updating of multiple resources, task automation becomes essential, lest there be no time left over for interpretation and commenting as to what it all means.

In some cases, this might even enable innovation: for example just as UH merges Cryosat2 and SMOS to better get at thin ice seasonally, we might take their product and overwrite RASM-ESRL ice thickness on its periphery where a model will be suboptimal relative to observational data..

The sea ice thickness animation below is one that automation could roll over once a day. It joins 39 daily initial states to ten days of forecast. The ESRL archive of D0's begins on Aug 15th and runs to Sept 28th at which point daily forecasts take over. (There is some sort of normalization glitch prior to Sept 16th.)

Technical note: automating conflict resolution between files 'too big to load' and maximal size of display that will run without a click is fairly easy: a montage of all the frames determines safe autocrop boundaries that won't clip off ice in any of the frames. Three clicks in Gimp.

Technical note: forum software won't accept png animations though web browsers do. For overlays, say Hycom over ESRL thickness, the number of colors will double the gif limit of 8-bit. Each frame has to be cut down to 256 colors in total; that process forces loss of smoothness (gross dithering of minor colors). However palettes like UH AMRS2 get by with 100 colors. Hycom can then be allocated  the remaining 156 (via mode shift to indexed color in Gimp). That is plenty for both to display colors smoothly in the final gif.


https://forum.arctic-sea-ice.net/index.php/topic,1259.msg130182.html#msg130182
Title: Re: The 2017/2018 freezing season
Post by: Niall Dollard on September 30, 2017, 09:44:46 AM
Thanks A Team.

I remember asking about strange ice thicknesses near the ice edge in the Beaufort earlier in the month. So it was a normalisation glitch. Comparing these before and after glitch still images attached, the glitch was especially pronounced in the magenta highlighted areas, with thicknesses stepping from dark red to blue.

But after Sept 16th, the thicknesses do look on a par with what you would expect this year - before that date, thicknesses are not trustworthy. 
Title: Re: The 2017/2018 freezing season
Post by: Sterks on September 30, 2017, 12:17:57 PM
Thanks A Team.

I remember asking about strange ice thicknesses near the ice edge in the Beaufort earlier in the month. So it was a normalisation glitch. Comparing these before and after glitch still images attached, the glitch was especially pronounced in the magenta highlighted areas, with thicknesses stepping from dark red to blue.

But after Sept 16th, the thicknesses do look on a par with what you would expect this year - before that date, thicknesses are not trustworthy.
The ice model was forced to assimilate a PIOMAS update. (?)
Title: Re: The 2017/2018 freezing season
Post by: echoughton on September 30, 2017, 12:52:51 PM
Daniel B And others...uh...the freezing season is tracking like every season ever...it's freezing
Title: Re: The 2017/2018 freezing season
Post by: Daniel B. on September 30, 2017, 02:22:42 PM
Daniel B And others...uh...the freezing season is tracking like every season ever...it's freezing
lol.

Water does what is always does when the temperature drops?
Title: Re: The 2017/2018 freezing season
Post by: gerontocrat on September 30, 2017, 02:28:42 PM
Yes, it's freezing - but how quickly? DMI 80+ degrees north graph.
Title: Re: The 2017/2018 freezing season
Post by: oren on September 30, 2017, 03:21:43 PM
After the initial refreeze of the.central CAB, the refreezing very much stalled, but in the last few days it picked up vigorously. Initially I would have bet on another lame freezing season, but now I am back on the fence.
Title: Re: The 2017/2018 freezing season
Post by: A-Team on September 30, 2017, 03:44:46 PM
Quote
after Sept 16th, the thicknesses do look on a par with what you would expect this year - before that date, thicknesses are not trustworthy.
No, it's just a scaling visualization issue. Here the ESRL program is experimental, PanoplyCL is in beta, and I am making novel forum-adapted graphics out of raw data files like RASM-ESRL_2017-09-28-00_t048.nc rather than using 'official' ESRL web products (from which glitches may have vanished in their better-informed processing). There's no methods paper out yet.

Here's how scaling works: the ice thickness numbers modeled for a given day fall within a certain range. If PanoplyCL uses the default 'fit to data' setting, the palette colors will be assigned evenly over the full range of data values, even if some are sparsely occupied or altogether unrepresented.

However maybe 0.5% are artifactual outliers due to some internal problem in the calculation, for example near the coastline. These outliers can fluctuate wildly from day to day. If they are not filtered out somehow, because palette color assignments follow the range in 'fit to data' mode, the colors of the map won't be consistent from day to day (ie frame to frame in the animation).

Outlying thicknesses will get palette colors on the far right, intermediate colors won't be used at all, and core range thicknesses will be crammed into what's still available in the palette.

Meanwhile, the core range that ice thicknesses take on is much smaller and varies seasonally but very little from day to day. After skimming through the files, I replaced 'fit to data' with a fixed 3.6 m for the outer limit of thickness for all 49 days to get consistent coloration. Ice at higher thickness, some reasonable like 3.65 m and some obviously erroneous but rare outliers like 17.5 m get collapsed into the final palette color, just like in WorldView.

Around 16 Sept, ESRL seems to have refined the internal algorithmic glitch that was creating the outliers. From that date on, the ranges varied little and 'fit to data' barely differed from 'fit to 3.6'. That doesn't imply that the earlier data was wrong, only that 'fit to 3.6' wasn't the right scale for synching the palette scale to actual thicknesses or for smooth color transitions over the change.

Since the early parts of the animation were well synched to each other up until the glitch, they likely just need a constant rescale, say 5.0 instead of 3.6 m, to make the whole series harmonious. To determine that rescale, reload the the 15th and 16th in Panoply's linear grayscale and divide in Combine Arrays.

Some computer mishap seems to have occurred on Sept 10th. There are data gaps on 8th and then again for the 11th and 12th which have not been filled. On the 13th (and subsequently) when the archive resumed, they dropped the t024.nc time slot, going right to forecast day two t048.nc. Elsewhere a file would be described by its start and stop hours, eg t000 to t024.

These mishaps occur in all the archives. Yesterday, on another forum, a pacman data gap in AMSR2 drew comment. That's not been fixed and cannot be fixed if the responsible satellite or receiving ground station had a glitch.

In the bigger picture of netCDF climate files, pre-calculated statistical properties of the data distribution should be part of the file, not sit implicit in machine-readable binary. That would allow consistent automated definition of outliers as well as 'histogram equalization', both discussed at length over at Dev Corner. Panoply does provide thicknesses averaged over latitude (with land masked out) which is a start.

RASM-ESRL ice thickness has commonality with sparsely gridded Hycom. Both of these are in serious conflict with the less-nuanced ringed display of Piomas. A round of Cryosat2 flight lines takes a month to get close to full coverage; it's challenging to compare experiment with model.

The only thickness reset available is new ice forming each fall from open water. The older ice will wander off farther and farther into uncertainty as time goes on, whatever the modeling system. Ice thickness is a derived product in RASM-ESRL; they have 49 outputs overall.

From the perspective of differential equations, where did the initial conditions come from on the start date? It's time evolution won't be any better than that. Daily satellite inputs might reset attributes like ice boundary or melt pond fraction but thickness is known only on the open water (zero).
Quote
The model is initialized with the NOAA Global Forecast System (GFS) analyses and the Advanced Microwave Scanning Radiometer 2 (AMSR2) sea ice concentrations. The model is forced at the lateral boundaries by 3-hourly GFS forecasts of winds, temperature, and water vapor.  Weather Research and Forecasting (WRF3.5.1; run with 40 vertical levels) atmospheric model; the Parallel Ocean Program (POP2) model; the Los Alamos Community Ice Model (CICE5.1; and the NCAR Community Land Model (CLM4.5). All components, run at 10 km horizontal resolution, are coupled using a regionalized version of the CESM flux coupler (CPL7), which includes modifications (Roberts et al. 2014) important for resolving the sea ice pack response to weather events. Other model optimizations include: a bulk double-moment cloud microphysics scheme for droplets and frozen hydrometeors, running ensemble forecasts initialized with GEFS ensemble members, and extending the model domain to include the Bering Strait and Svalbard.
The most striking feature in RASM-ESRL thickness animation (passing over glitch) is how little the ice has moved about this summer (or grown or shrunk). The patches of enhanced thickness jostle about indecisively. There's no indication of textbook Transpolar Drift or Beaufort Gyre. If that persists, the plan for the frozen-in Polarstern might need serious revision.

The animation below shows the dramatic effects in map coloration using a fixed palette to display the same data in core vs outlier range settings. Scientific visualization has a great many issues; we can explore them only when the data archiving site provides the underlying netCDF file. Many do, but others just post their favorite depiction (which may use an awful palette and bury data under text and grid lines).
Title: Re: The 2017/2018 freezing season
Post by: Pavel on September 30, 2017, 04:00:40 PM
Yes, it's freezing - but how quickly? DMI 80+ degrees north graph.
Looks slightly colder than 2016 but persistant heat advection forecasted in next 10 days. The freeze up of Laptev/North Kara may happen a bit earlier than last year but in general it tracks like a quite mild (not extremely mild)
Title: Re: The 2017/2018 freezing season
Post by: numerobis on September 30, 2017, 07:59:25 PM
There’s a rather decent Arctic cyclone over Hudson Strait and south Baffin today. YFB barometer reads 985 hPa and falling. It’s dumping 10+ cm of snow, which means insolation down here is getting bumped back up from now on.

Edit: 981 in Iqaluit, 972 min pressure on this storm.

We could be making so much electricity right now!
Title: Re: The 2017/2018 freezing season
Post by: Niall Dollard on September 30, 2017, 10:11:01 PM
Quote
No, it's just a scaling visualization issue.

That's no problem. No I don't have any issue with the ESRL data and I appreciate all the development work.  :)

Recent snow cover image from US Natice shows cover extending through northern Russia. However not a lot yet to the northeast of Yakutsk.
Title: Re: The 2017/2018 freezing season
Post by: A-Team on September 30, 2017, 10:20:39 PM
Here is the official ESRL ice thickness product from Aug 22nd to Sept 28th, Alaska down, non-stereographic projection. Or rather thinness. They set a palette cut-off at 1.6 m or less. Everything thicker is given the same color as the 1.6 m bin.

Someone was complaining about this up-forum, why not use a higher cut-off like 2.6 m (or more) and display the thicker ice too. That would have required 10 more palette colors. Right now, ESRL is using 16 colors already in a so-called paired palette. It's quite effective but pushing the upper limits already on workable number of discrete colors.

Whoever made this map, their interest was in displaying thinner ice and wind. These home page graphics are archived ok as REB_plots but as final gifs, not netCDF files. Otherwise we could have easily redone the graphic to a higher cut-off in an augmented or wholly different palette, in Greenland down stereographic without the wind vectors and lat lon lines.

Note prior to this date, the ESRL map did not cover the entire Arctic Ocean. They are unlikely to revisit earlier dates so the extensibility question comes up, how hard is it to add subsequent days to the current calendar coverage? Not hard at all. The file is at 3.5 MB for 34 days; it could be brought out to ~100 days before hitting forum limits.

They offer a D5 forecast to Oct 3rd, though not D1-D4. It has to be resized as its dimensions are off. That's attached separately rather than add to the initial state series. ESRL does not currently update those later as improved hindcasts.

It would be feasible, if we had the underlying netCDF, to see how they're doing by comparing old D5's with their later initial D0 for that date. However it's very hard to demonstrate forecast skill during long stretches of uneventful weather as the baseline forecast-to-beat  (each day just like the previous) does so well.

The ESRL map does manage to pick up the persistent polynya on some days (as flashes of white), even though the resolution is nothing like the 3.125 km of UH AMSR2 that displays it clearly.

I looked around to see if this was a known matlab, ncr, gmt, panoply, or colorbrewer palette. It wasn't. Methods for capturing a nice palette like this and saving it into Panoply are described over at Dev Corner. It could be used to color re-color the time series above but it would be difficult to match ESRL's projection without more information.
Title: Re: The 2017/2018 freezing season
Post by: Niall Dollard on October 01, 2017, 08:37:18 PM
Some Russian coastal freezing extending into the Laptev (bottom centre) , showing up on Worldview today. 
Title: Re: The 2017/2018 freezing season
Post by: A-Team on October 01, 2017, 11:47:12 PM
Clouds in the summer play two important roles by reflecting incident sunlight and intervening in upwelling and downwelling radiative transfer processes. By September, the sunlight is effectively gone and the interest shifts to the insulating properties of clouds, keeping heat in and so delaying open water refreezing and opposing the thickening of ice.

However the quantitative details are quite complicated and we will need to follow energy fluxes this fall, the best/only source for that apparently being certain ESRL products.

The less-than-great animation below shows the cloud deck for the month of Sept in channels 7-2-1 of Terra Modis. Because the satellite pulls together pie-shaped wedges as it runs through a full cycle of its near-polar orbit over the course of a day, the image is a composite of different times.

Further, as the season progresses, the 'pole hole' of Arctic darkness gets larger every day, making cloud monitoring impractical already by Oct 1st. The blue line marks the open water boundary as derived from UH AMSR2. Outside the line, we are looking at the effect of clouds on sea water freezing; inside the line, on the effect on ice thickening.

Relevant to this, ESRL provides daily surface air temperature, air velocity ,sea surface temperature, ice surface temperature, salinity, snow thickness, ice thickness, bottom and lateral freezing rates, and ice edge evolutionn (newly fixed, freezehour). Salinity affects the freezing temperature of sea water, lowering it in the Arctic to -1.8ºC, though following full brine exclusion 0.1ºC is enough for re-melt.

From these and cloud satellite inputs, the RASM_ESRL model derives various energy fluxes of interest to us this season: net surface energy flux (Arctic24, lower left, below), net energy flux at surface (Arctic23, UL left), longwave flux (Arctic22 LL), GFS net shortwave flux (Arctic 22 UR), snow/ice/ocean absorbed solar flux (Arctic 22 LR, flatlining now), 310K potential vorticity and surface theta (Arctic20), heat flux ice to ocean at ice edge (Arctic15), net energy flux at surface yet again (Arctic14), longwave net, shortwave through ice to ocean, snow/ice broadband albedo (all in Arctic11), precip (Arctic9 and 4), ice thickness thermodynamic tendency and snow melt (Arctic3), and snow depth (Arctic1 LL), the bottom line being refreeze season history and forecasts.

These will take some time to go through to see which holds the most interest for us. The net surface energy flux, below, is entirely in the negative over the forecast period. The map is one of their older formats emphasizing an Alaska perspective rather than the whole Arctic Ocean we want. Since no netCDF file is provided, only the final 28-frame gif, there's no role for Panoply here, just Gimp. It's also quite a nuisance to extract only the D0 from each many separate animations in order to construct the daily repository without the forecasts.

Unfortunately no one here follows the three main cloud satellites, two of which are in the A-train constellation. These may have data archives that we can work with directly in Panoply.

-- CloudSat, a cooperative effort between NASA and the Canadian Space Agency, runs 2 minutes and 30 seconds behind Aqua, launched with CALIPSO on April 28, 2006.

-- CALIPSO, a joint effort of CNES and NASA, follows CloudSat by no more than 15 seconds, launched on April 28, 2006
Title: Re: The 2017/2018 freezing season
Post by: Pavel on October 02, 2017, 10:15:07 AM
The early freeze up along the Taimyr peninsula this year
Title: Re: The 2017/2018 freezing season
Post by: A-Team on October 03, 2017, 12:53:06 AM
Here is the multi-year comparison, both visual and boolean, for 2017 vs 2012-2016. This is the last day of the year for which 2012 is in the UH AMSR2 archive. This year had quite respectable melt except when compared to 2012.

The lower images look at the peripheral freezing forecast from ESRL, called freezehour.gif on their web page archive. This is a difficult scientific visualization problem because so little of the image is ice margin.

Initially, they had the rest of the ice set off from open water (white) but re-used a palette color that had been set aside for hours of forecast. Also they had far too many colors using the same small space. Next they reduced the palette but this time used white for both a middle forecast hour and open water.

The underlying problem across ESRL's graphics is the difference between 0 and NaN. They need a consistent open water resp. ice mask. (For a variable like ice surface temperature, open water has no applicable number, not the same as zero in the palette.) Here the notion of replacing a gif animation using colors for successive frames isn't effective or accurate, the latter because there's back and forth on freezing as well as ice movement.

The top animation, not provided at ESRL, uses a sequence of 24 consecutive static forecast images. It shows the ever-widening periphery of the ice pack quite well. The way they have the archive structured, it is necessary to download a large compressed Reb_plot bundle for each day and then fish through all this folders for instances of the graphic, even if as here only one of the 44 graphic products is wanted. We are in the process of fixing that.

The bottom animation, also not provided at ESRL, restores time to their static image by cycling through the palette. This is better but still doesn't accommodate ice motion which is weird since they have this forecast elsewhere. I don't know what software they are using but it is not matlab, NCAR's NCL, Panoply, Photoshop, ImageJ, or Gimp.

What we are after here, come freeze-over in Jan 18, is a map of first year ice colored by its freeze-up date. In other words, open water that forms ice in early October has 3 extra months of thickening available relative to Chukchi ice that first freezes in late December. Other things being equal, the ice last to freeze will be the first to melt.

As more of the Arctic Ocean ice pack becomes first or second year ice, there's a benefit to age class refinement. If the lack of significant weather persists, compaction, dispersion and export will not interfere with this mark-up and tracking newly formed ice.
Title: Re: The 2017/2018 freezing season
Post by: Thomas Barlow on October 03, 2017, 04:17:03 PM
Peter Wadhams interview on Radio NZ - Oct. 2 2017.
""You can't measure ice thickness from space...well, only with extreme difficulty...so the best way to measure thickness is to sail underneath the ice, and use an upward-looking echo-sounder.""

http://www.radionz.co.nz/national/programmes/afternoons/audio/201860805/peter-wadhams-preparing-for-an-arctic-without-ice (http://www.radionz.co.nz/national/programmes/afternoons/audio/201860805/peter-wadhams-preparing-for-an-arctic-without-ice)
Title: Re: The 2017/2018 freezing season
Post by: Niall Dollard on October 03, 2017, 05:08:44 PM
I like that freeze progression image, A Team.

Current forecast models are suggesting the Arctic is near to its peak temperature anomaly (for the next 10 days) around now. The recent Scandanavian anticyclone has directed a surge of warmth north but at least the Arctic has been spared the remnants of tropical storms Maria and Lee, which instead have moved in an easterly path across the Atlantic.

Instead of high pressure, the Arctic is set to be dominated by a series of slack depressions. 850hPa temperature anomalies are still showing high temps over the Beaufort and later through the CAA and northern Greenland. But temperature anomalies drop again over on the Russian side  for the Laptev, ESS and at last there are signs of progress being made towards the Chukchi.

Given the still warm SST anomalies especially north of Alaska, it is difficult to see how the Arctic can cool to a level that would bring the DMI N80 graph close to the 1958-2002 mean. Very unlikely, until the ocean's ice cover north of Alaska/Russia is complete.   
Title: Re: The 2017/2018 freezing season
Post by: A-Team on October 03, 2017, 07:12:58 PM
Quote
Given the still warm SST anomalies especially north of Alaska, it is difficult to see how the Arctic can cool to a level that would bring the DMI N80 graph close to the 1958-2002 mean.
Looking below at Arctic surface temperatures and surface energy flux from ESRL from 04 Sep to 02 Oct 17 and noting the forecast out 09 Oct is featured at their web site, it seems that regardless of clouds, fading sun, and blanketing snow that the surface energy flux has been almost entirely negative (ie the top half of the palette is barely used.

Further, although how the energy flux is calculated is buried somewhere in the model used, it is apparent that over this time frame, the flux is (unsurprisingly) strongly correlated with temperature. That's somewhat less evident in the 6 hourly forecast as the palettes are set.

Technical note: Here "RASM-ESRL net energy flux at surface" appears in three different figures. Arctic 14.gif and Arctic23.gif are identical whereas Arctic24 is colored differently, with the scale extending to 105 to -120 w/m2 instead of 70 to -80 like the other two. Its legend is also displaced slightly and its title is worded slightly differently but it has the needed land mask. All three use the same diverging paired palette which is unsystematically constructed with respect to lightness, luminosity, saturation, hue and perception. These are shown in columns below relative to the palette chosen.

This time of year, all the fluxes are moderately negative; there is no use at all of the positive side of the scale. However extreme negative energy flues are observed down to -120, establishing that -80 is inadequate (lumps values that should be distinguished). Again, white should not be used as zero as it becomes conflated with non-ice surface white. It's rather unusual to use the same palette for temperature and energy flux as the units are very different but it works fairly well here because the latter is in part derived from the former. In summary, we could do this product significantly better if the netCDF files were available.
Title: Re: The 2017/2018 freezing season
Post by: A-Team on October 03, 2017, 07:43:31 PM
Quote
Peter Wadhams interview on Radio NZ - Oct. 2 2017"You can't measure ice thickness from space...well, only with extreme difficulty...so the best way to measure thickness is to sail underneath the ice, and use an upward-looking echo-sounder."
http://www.radionz.co.nz/national/programmes/afternoons/audio/201860805/peter-wadhams-preparing-for-an-arctic-without-ice (http://www.radionz.co.nz/national/programmes/afternoons/audio/201860805/peter-wadhams-preparing-for-an-arctic-without-ice)
That may be, provided the sub can keep a perfectly level course despite passing through waters of different buoyancy. However, the expense is colossal, it only provides a very narrow swath of thicknesses, and it's not likely to be repeated regularly during the year.

It may not be any more accurate than em induction thicknesses based from helicopter or plane. If those are coordinated with ice augering from a surface ship, a fairly wide swath can be obtained with direct calibration. However there won't be repeat measurements at the same site over the year; repeat data from the same drifting floe is probably more informative.

Cryostat2 is the only device whose swaths add up to areal coverage. However it has problematic aspects such as problems with snow cover, thin ice with negligible freeboard, and the month needed to complete orbital coverage means each swath has a different time stamp. That leaves ice thickness modeling which is fraught with issues as well.

In summary, ice thickness remains very difficult to measure despite its importance and the decades of effort. Thickness is not the whole story because the ice temperature profile is also important to melt thermodynamics and mechanical state of the ice. More buoys could be deployed, 1000x of what is planned for 2018, for a tiny fraction of submarine or surface ship charter costs.
Title: Re: The 2017/2018 freezing season
Post by: Shared Humanity on October 03, 2017, 08:15:15 PM
Peter Wadhams interview on Radio NZ - Oct. 2 2017.
""You can't measure ice thickness from space...well, only with extreme difficulty...so the best way to measure thickness is to sail underneath the ice, and use an upward-looking echo-sounder.""

http://www.radionz.co.nz/national/programmes/afternoons/audio/201860805/peter-wadhams-preparing-for-an-arctic-without-ice (http://www.radionz.co.nz/national/programmes/afternoons/audio/201860805/peter-wadhams-preparing-for-an-arctic-without-ice)

Having accurate measures of thickness is important to evaluate the Arctic but it is insufficient. I am concerned about the quality of the ice of any thickness. Is today's 3 meter thick MYI the same as ice of 20 years ago or even 10 years ago when you have winters like the winter past and compare it to 2004?
Title: Re: The 2017/2018 freezing season
Post by: Shared Humanity on October 03, 2017, 08:20:14 PM
The 1st three months of 2017 look remarkably similar to the start of 2016. It remains to be seen if 2017 closes out the year in a fashion similar to 2016 but these warm winters must be having a deleterious effect on the quality of the ice and not just thickness but the physical properties of the ice as well.
Title: Re: The 2017/2018 freezing season
Post by: Pavel on October 03, 2017, 09:06:24 PM
Despite the warmer temperatures the freezing season north of 80 latitude still long and melting season is short and weak. The ice could be melted only if it will be exported. From the last melting season I'm convinced sea ice in the high Arctic is well protected, it's almost impossible to get SIE below 3 mln despite the warmer winters
Title: Re: The 2017/2018 freezing season
Post by: Shared Humanity on October 04, 2017, 02:19:16 PM
You've missed my point entirely. My concern is not about SIE or its annual rise and fall that coincide with the freeze and melt seasons. My concern is about a qualitative shift in the ice that remains at the end of any melt season. A freeze season with temperature anomalies of 5C to 10C has to have an effect on this MYI ice and not a good one.

There have been reports of "buttery" MYI by crews on ships that traverse the heart of the CAB where MYI predominates. This is in contrast to the rigid, rock solid ice that was virtually impassable in the past. Many far more knowledgeable individuals on this site could speak to the possible transitions we can expect in the quality of the ice.

I will be following this freeze season closely and hope the temperature anomalies are mild and do not come close to 2016.
Title: Re: The 2017/2018 freezing season
Post by: Thomas Barlow on October 05, 2017, 04:20:54 AM
Quote
Peter Wadhams interview on Radio NZ - Oct. 2 2017"You can't measure ice thickness from space...well, only with extreme difficulty...so the best way to measure thickness is to sail underneath the ice, and use an upward-looking echo-sounder."
http://www.radionz.co.nz/national/programmes/afternoons/audio/201860805/peter-wadhams-preparing-for-an-arctic-without-ice (http://www.radionz.co.nz/national/programmes/afternoons/audio/201860805/peter-wadhams-preparing-for-an-arctic-without-ice)
Quote
That may be, provided the sub can keep a perfectly level course despite passing through waters of different buoyancy.
Pretty sure they accounted for that  ::)

Quote
However, the expense is colossal
It's paid for by Her Majesty's Royal Navy. On a Navy sub.

Quote
it only provides a very narrow swath of thicknesses, and it's not likely to be repeated regularly during the year.
Apparently not, according the Wadhams .. expert on the topic.

Quote
It may not be any more accurate than em induction thicknesses based from helicopter or plane.
Again, the actual expert claims otherwise. I suggest you get several papers published in respected peer-reviewed journals on the topic, and then, maybe, you can take it up with him.

Title: Re: The 2017/2018 freezing season
Post by: slow wing on October 05, 2017, 05:19:34 AM
...More buoys could be deployed, 1000x of what is planned for 2018, for a tiny fraction of submarine or surface ship charter costs.
Yes, true and important. The graphical display of the models is getting so much better but the models have insufficient calibration data from the water. A 1000x bigger deployment of buoys was discussed in last year's freezing season thread, 11 months ago - e.g. #481 (https://forum.arctic-sea-ice.net/index.php/topic,1611.msg92856.html#msg92856) - with links to further discussion. A major scale-up of buoy deployment really deserves a thread of its own.
Title: Re: The 2017/2018 freezing season
Post by: meddoc on October 05, 2017, 11:52:01 AM
Hycom is showing ongoing Fram Export & Thinning, Desintegration in the CAA- I guess, the Garlic Press is still active.

https://www7320.nrlssc.navy.mil/hycomARC/navo/arcticictn_nowcast_anim30d.gif
Title: Re: The 2017/2018 freezing season
Post by: Adam Ash on October 05, 2017, 12:43:18 PM
Ice thicness measurements taken from above are based on the above water freeboard, as I understand it.
However measurements of the ice bottom surface taken from below looking up would gave ten times the resolution, and give an estimate of volume whuch is thus an order of magnitude better than top down.
Of course we then run into issues with frequency and distributiin of transects compared with from the sky.  But there some ROV gliders which may have the required endurance to get more ice depth data.

Big bucks, either way. Some may ask; Are we just paying for a better view of the sinking of the Titanic?  The ship is lost, whether we measure it more accurately or not.
Title: Re: The 2017/2018 freezing season
Post by: Daniel B. on October 05, 2017, 03:45:28 PM
You've missed my point entirely. My concern is not about SIE or its annual rise and fall that coincide with the freeze and melt seasons. My concern is about a qualitative shift in the ice that remains at the end of any melt season. A freeze season with temperature anomalies of 5C to 10C has to have an effect on this MYI ice and not a good one.

There have been reports of "buttery" MYI by crews on ships that traverse the heart of the CAB where MYI predominates. This is in contrast to the rigid, rock solid ice that was virtually impassable in the past. Many far more knowledgeable individuals on this site could speak to the possible transitions we can expect in the quality of the ice.

I will be following this freeze season closely and hope the temperature anomalies are mild and do not come close to 2016.

The short answer is, "it depends."  If the ice has frozen from the sea water, then yes, 3M thick ice will look the same today as it did 20 years ago.  However, if the ice has contributions from land-based glacial ice, then the answer is no, as the glacial ice is much denser.  That said, much of the ice in the open ocean, particularly in the Barents, Chukchi, and other areas that melt every summer, will refreeze similarly to that in the past.  It requires the same loss in energy to form the same thickness of ice today, as it did 20 years ago.
Title: Re: The 2017/2018 freezing season
Post by: mdoliner on October 05, 2017, 07:12:05 PM
The sun heats the earth and the earth re-radiates some of that heat into cold space. How much it radiates is a function of its temperature. Heat always moves from hot to cold. When it reaches the poles it melts ice. It takes latent heat, heat that does not raise the temperature, to melt ice. When ice melts and temperature stays the same the amount of heat re-radiated into space remains the same. So the imbalance remains. If all the extra heat was latent heat, the earth would continue to absorb extra heat until all the ice was gone. This would be true even if the incoming-outgoing imbalance were small. Only an increase in the earth's temperature can restore the balance.

Total melting doesn't happen with small imbalances because of the inefficiencies in the transfer of heat to the poles. Much of the extra heat does raise the temperature and never gets to the poles simply because of the inefficiency of winds and currents. Re-radiation increases. The deformation of the jet stream and the disruption of currents will, given the second law of thermodynamics, tend to reduce these inefficiencies. So, paradoxically, since there is an imbalance, no global warming, where all the heat goes into melting ice, is worse than global warming, because it won't stop until all the ice is gone.
Title: Re: The 2017/2018 freezing season
Post by: Niall Dollard on October 05, 2017, 08:55:45 PM
ESRL forecast chart indicates the Laptev Sea will be almost ringed by thin ice in about a weeks time.

 
Title: Re: The 2017/2018 freezing season
Post by: A-Team on October 06, 2017, 01:02:51 AM
ESRL forecast for the Atlantic Water area above Svalbard, Yermak Plateau, and Severnya Zemlya out to Oct 14th. Shows extent, thickness, snow, and air temperatures -- winter is closing in, only the area above Svalbard is staying open.
Title: Re: The 2017/2018 freezing season
Post by: Thomas Barlow on October 06, 2017, 04:34:07 AM
This freezing season is off to a horrendously bad start - see below. Add to that, the latest assessments are that globally, September shattered records.
Title: Re: The 2017/2018 freezing season
Post by: Pavel on October 06, 2017, 08:28:59 AM
It tracks colder than last year. Also the freezing of the Laptev sea happens two weeks earlier than 2016. So I wouldn't say this years' start is a horrendously bad start
Title: Re: The 2017/2018 freezing season
Post by: Neven on October 06, 2017, 12:40:42 PM
The 2017 global sea ice extent trend line is at a point where it has to decide whether it will join the pack of trend lines, or tag along with the 2016 trend line:
Title: Re: The 2017/2018 freezing season
Post by: Niall Dollard on October 06, 2017, 04:31:12 PM
A section of the Laptev Sea (Russian coast to the south) showing how quickly ice can advance in only one day.

Title: Re: The 2017/2018 freezing season
Post by: Shared Humanity on October 06, 2017, 04:32:34 PM
It tracks colder than last year. Also the freezing of the Laptev sea happens two weeks earlier than 2016. So I wouldn't say this years' start is a horrendously bad start

2016 was the warmest Arctic winter on record and finished with record low volume at the end of the freeze. The chart shows this winter close to and trending similarly to 2016.

Depends on what we consider horrendous, I suppose.
Title: Re: The 2017/2018 freezing season
Post by: Shared Humanity on October 06, 2017, 04:35:53 PM
The 2017 global sea ice extent trend line is at a point where it has to decide whether it will join the pack of trend lines, or tag along with the 2016 trend line:

It has trended persistently lower this year when compared to last. Hope this trend does not continue.
Title: Re: The 2017/2018 freezing season
Post by: Thomas Barlow on October 06, 2017, 06:15:13 PM
It tracks colder than last year. Also the freezing of the Laptev sea happens two weeks earlier than 2016. So I wouldn't say this years' start is a horrendously bad start

 Last year WAS horrendous, and local conditions are NOT the whole Arctic Ocean.
Title: Re: The 2017/2018 freezing season
Post by: Pavel on October 06, 2017, 07:02:47 PM
Of course it depends on how one considers horrendous. If I clearly understand what does mean "horrendous", it doesn't looks horrendous for me. We have already experienced the bullet and the cannonball by the end of the freezing season, so horrendous should be something more :) The thing that one should be concerned about is the pacific side.It still looks warm and iceless, I'm curious to see how the Chuckchi/Beaufort/ESS will track further in the season
Title: Re: The 2017/2018 freezing season
Post by: Daniel B. on October 06, 2017, 07:41:10 PM
Of course it depends on how one considers horrendous. If I clearly understand what does mean "horrendous", it doesn't looks horrendous for me. The thing that one should be concerned about is the Pacific side. It still looks warm and iceless, I'm curious to see how Chuckchi/Beaufort/ESS will track further in the season

I have to agree with you on that.  Compared to recent years, it was not so bad.  Looking at the previous decade, only three had a higher minimum extent.  The low maximum last winter was a little concerning, but the 2017 melt season was fairly average.  The total melt for the year (max - min) was rather unspectacular, 9.78 compare to an average 0f 9.58, and the lowest total melt since 2006.  We will see what happens during the freezing season. 
Title: Re: The 2017/2018 freezing season
Post by: dosibl on October 06, 2017, 08:09:48 PM
FDD trends might be lining up with 2016, but its too early to tell. The big story last year was the extremely warm moments in the fall, that + the global area/extent graphs generated enough buzz that the media reported on it (and I suspect resulted in a bunch of new readers on this forum, including myself), I'll be curious to see if we get anything similar this year.
Title: Re: The 2017/2018 freezing season
Post by: Shared Humanity on October 06, 2017, 10:23:14 PM
I'm curious to see how the Chuckchi/Beaufort/ESS will track further in the season

Further in the season the Chuckchi, Beaufort and ESS will freeze as seawater wants to do and, no doubt, you will herald this as further evidence of the benign nature of our condition.
Title: Re: The 2017/2018 freezing season
Post by: Pavel on October 06, 2017, 11:08:37 PM
In the melting season I was expecting a disaster, but now I try be realistic and to avoid exaggerated defenitions. Pacific side is warm, it was clear since July. GFS forecasted more heat advection from the Pacific ocean in a week. In generall could be slighly colder than 2016, something between the cannonball and the bullet. But the season is long and each month is important
Title: Re: The 2017/2018 freezing season
Post by: Meirion on October 07, 2017, 11:28:32 AM
If you compare post 2000 Arctic with 1980s and 1990s http://ocean.dmi.dk/arctic/meant80n.uk.php (http://ocean.dmi.dk/arctic/meant80n.uk.php) there is a definite trend to warm autumn, winter, spring, cool summer. Whether that means a couple of cool summers would decimate the icepack or whether there is a connection between the cool summers and the other three seasons being warm who knows?
Title: Re: The 2017/2018 freezing season
Post by: Dharma Rupa on October 07, 2017, 03:05:42 PM
Temperatures at night tend to fall to the dew point.  The major factor determining the dew point is the presence or absence of nearby open water.  The largest recent change in the Arctic climate has been the significant increase in open water.

Temperatures during the day tend to rise as sunlight hits the surface.  The major factor preventing sunlight from reaching the surface is clouds.  Clouds tend to increase in the presence of open water.  The largest recent change in the Arctic climate has been the significant increase in open water.
Title: Re: The 2017/2018 freezing season
Post by: Thomas Barlow on October 07, 2017, 05:15:50 PM
Of course it depends on how one considers horrendous. If I clearly understand what does mean "horrendous", it doesn't looks horrendous for me. We have already experienced the bullet and the cannonball by the end of the freezing season, so horrendous should be something more :) The thing that one should be concerned about is the pacific side.It still looks warm and iceless, I'm curious to see how the Chuckchi/Beaufort/ESS will track further in the season
Fair enough. I tend to look at recent years as all in the same boat. Until I see it all jump back up to pre-1990 levels, I won't consider it positive news. Maybe because I was promoting renewable energy in the early 1980s, and dedicated my life's work to warning of the dangers ahead, and finding solutions. To me, a slightly better "bad year" this year is not "dodging a bullet", as some call it. I think that's newcomers to the pollution disaster (ie. 10-15 years only) saying that kind of thing.
Title: Re: The 2017/2018 freezing season
Post by: Thomas Barlow on October 07, 2017, 05:59:39 PM
but the 2017 melt season was fairly average.  The total melt for the year (max - min) was rather unspectacular, 9.78 compare to an average 0f 9.58, and the lowest total melt since 2006.
I think that is incorrect. You forget that the 'average' on the extent graphs descends each year due to recent lows. If the 'average' was left at say, pre-1999 level, then the difference would seem much greater. It is like the drought in California. The average on graphs and charts now include a 5 year period of the worst drought on record, so the 'average' is now much lower than it was 7-10 years ago. There is nothing 'fairly average' going on with the Arctic Ocean ice right now. When you see it jump back to pre-1990 levels, you can say 'we dodged a bullet'. Let me know when that happens.
Just sayin'
Title: Re: The 2017/2018 freezing season
Post by: Shared Humanity on October 07, 2017, 06:58:42 PM
If you compare post 2000 Arctic with 1980s and 1990s http://ocean.dmi.dk/arctic/meant80n.uk.php (http://ocean.dmi.dk/arctic/meant80n.uk.php) there is a definite trend to warm autumn, winter, spring, cool summer. Whether that means a couple of cool summers would decimate the icepack or whether there is a connection between the cool summers and the other three seasons being warm who knows?

Increased atmospheric moisture load, a cloudy Arctic with increased precipitation which previously was a cloudless, if cold, desert. The clouds in the winter block heat from radiating into space. The clouds in the summer, protect the ice from the sun and keep temperatures cool.
Title: Re: The 2017/2018 freezing season
Post by: Dharma Rupa on October 07, 2017, 08:05:55 PM
The clouds in the winter block heat from radiating into space.
That brings up some interesting questions about the relative importance of the different greenhouse effects of H2O, re-radiation and enthalopy; which I think I shall bring up in the Stupid Questions thread.
Title: Re: The 2017/2018 freezing season
Post by: A-Team on October 08, 2017, 12:35:12 AM
Here are the 2m air and snow/ice surface temperatures forecast out to Oct 14th, both as zonal graphs (averaged by latitude, land masked out) and as 2D maps, along with Hycom ice thickness, ice velocity vectors, and summary statistics by time stamp. Gimp layer assembly of Panoply 4.8.4 processing of REB.2017-10-04.nc
Title: Re: The 2017/2018 freezing season
Post by: Shared Humanity on October 08, 2017, 03:13:29 PM
Nice. A lot of info in such a small space.
Title: Re: The 2017/2018 freezing season
Post by: Shared Humanity on October 08, 2017, 07:56:37 PM
Too early to spot any clear deviations from the previous 5 years with a couple of exceptions. The Laptev is seeing early onset of freezing while the Greenland Sea is lagging slightly.
Title: Re: The 2017/2018 freezing season
Post by: A-Team on October 11, 2017, 04:49:48 PM
Quote
sidd: winter cloudiness at the pole is very important. that's something i would watch closely, since winter cloud is a huge brake on winter cool-down. ttown: water vapor in the clouds prevents long wave radiation from escaping from the surface and reflects it back downward.
Right, right again. But if we want to move beyond 'a snow blanket and clouds have (have not) been keeping the heat in' thus slowing (speeding) winter growth of ice extent and its thickness, thus preconditioning the 2018 melt season, ESRL offers various quantitative energy flux products as well as snow depth and rain monitoring.

The time series below shows four of the flux widgets from early Sept to mid Oct. These are a collection of initial states (ie bottom frame) taken off their daily forecast animation. Three of them use the same palette (upper left); SW stands for shortwave (visible light). The forecast extending out from the 10th to the 17th is provided at the ESRL web page in a larger format.

ESRL does not provide multi-year comparison data but that can be found in three cloud and radiation satellites that we do not follow.

Here are a few academic overviews of seasonal radiation balance and a trend graphic for extent, downwelling radiation, and clouds in September, from Lisan Lu.

https://www.whoi.edu/fileserver.do?id=164384&pt=2&p=58549 (https://www.whoi.edu/fileserver.do?id=164384&pt=2&p=58549)
http://journals.ametsoc.org/doi/10.1175/JCLI-D-15-0002.1 (http://journals.ametsoc.org/doi/10.1175/JCLI-D-15-0002.1)
http://journals.ametsoc.org/doi/abs/10.1175/JCLI-D-15-0238.1 (http://journals.ametsoc.org/doi/abs/10.1175/JCLI-D-15-0238.1)
https://www.nature.com/articles/srep38287 (https://www.nature.com/articles/srep38287)
Title: Re: The 2017/2018 freezing season
Post by: A-Team on October 11, 2017, 09:27:53 PM
Just testing whether the template we are aiming for over at Dev Corner -- ESRL 7-day forecast taking over from a post-minimum initial state time series -- is "too big to load" in which case some days or forecast hours will unfortunately have to be skipped over. However it seems to work ok, 9.4 MB in 57 frames.

Hopefully ESRL will switch this product (Arctic11.gif) over to whole-Arctic Ocean in the near future. However, there's something to be said for an emphasis on the Chukchi-Beaufort as that's been the last to freeze over (mid-December). That's perhaps unsurprising as the Bering Strait is much further south than Svalbard on the other side, 65.9º vs 77.9º latitudes or 12x111 km/deg = 1332 km.
Title: Re: The 2017/2018 freezing season
Post by: Pavel on October 12, 2017, 11:49:34 AM
Cryosat have resumed. I don't see any 3m or thicker ice and there's very little of thicker than 2,5m ice
Title: Re: The 2017/2018 freezing season
Post by: Feeltheburn on October 13, 2017, 06:30:27 PM
NSIDC shows an impressive gain of 1 million km2 in arctic sea ice extent since 1 Oct 2017, with 800,000 km2 more ice extent on 12 Oct 2017 compared to 12 Oct 2016.

That coupled with an unusual regrowth of Antarctic sea ice to reach a season max 9 Oct 2017 (so far) rather than earlier means the overall global ice extent has recovered quite nicely compared to its state a year ago when both arctic and Antarctic ice were miserably low at the same time.
Title: Re: The 2017/2018 freezing season
Post by: Jim Pettit on October 14, 2017, 03:32:44 PM
NSIDC shows an impressive gain of 1 million km2 in arctic sea ice extent since 1 Oct 2017, with 800,000 km2 more ice extent on 12 Oct 2017 compared to 12 Oct 2016.

That coupled with an unusual regrowth of Antarctic sea ice to reach a season max 9 Oct 2017 (so far) rather than earlier means the overall global ice extent has recovered quite nicely compared to its state a year ago when both arctic and Antarctic ice were miserably low at the same time.

Yes, there is substantially more Arctic sea ice extent now than there was on this same day last year. But it should be noted that the NSIDC ASIE increase of 1.038 km2 since October 1 is less than that measured in 2015, 2014, 2013, 2012, or 2010. Month-to-date, NSIDC SIE is still running below the ten-year average, and year-to-date, 2017 extent is deeply entrenched in second place. Bottom line, then: I'm not sure how "nicely" once can say it's recovering.
Title: Re: The 2017/2018 freezing season
Post by: A-Team on October 14, 2017, 05:11:00 PM
The time series below shows sea ice thickness from Oct 1st to the 13th followed by the ESRL forecast to the 18th. Ice 1.6m and thicker is not distinguished (shown with the same color). New ice is seen forming and thickening on the periphery but little growth occurs on ice that was already present at the seasonal minimum (as cold air can only freeze bottom water indirectly via heat equation conduction). The day 5 ice thickness graphic shows significant thinning anticipated north of Svalbard region by the 18th, not from melt so much as ice pack movement.

The Chukchi-Bering walrus population is no closer than ever, ~350 km, to sea ice lying over continental shelf, ie where food is within diving depth with ice haul-outs at hand. Consequently they have to rest on land haul-outs where juvenile walruses are at great risk from stampedes, killed by the thousand in documented events. There are two known walrus haul-outs on the south side of Wrangel Island; some ~230 similarly stranded polar bears on the north side of Wrangel were recently seen feeding on a beached bowhead whale.

Technical note: the D0 frames are taken from icethicknessday0.gif up until the 13th, at which point D5's are taken from icethicknessday5.gif with the 9th supplying the 14th, the 10th the 15th and so on. ESRL still has not fixed the sizing bug that makes these slightly different in proportion, though the palette has finally stabilized. It would have been better to combine these with the intermediate days in a small gif so that the final day could supply the forecast days.
Title: Re: The 2017/2018 freezing season
Post by: Sterks on October 14, 2017, 08:25:53 PM
Therefore, expect a normal or above-normal ice extent growth.
Title: Re: The 2017/2018 freezing season
Post by: A-Team on October 14, 2017, 10:07:47 PM
Here is a comparison of the month of Oct for 2017 (upper) vs 2016 (lower). This being only mid-Oct of 2017 and two weeks being beyond the reach of any prediction system, animation forecast components stall out, frames become static as they reach their limits.

We've had posts this last month asserting the weather is not only a sure thing this fall, but even next spring, indeed the 2018 melt season is a done deal, and one person wrote off the 2018 freeze season already. There's a difference between knowledge and nonsense. D5, D7, maybe some value in D10, but even D15 appears completely out of reach. Meaningful seasonal forecast skill is still a pipe dream: the only site that got the last ENSO right was the Old Farmer's Almanac.

Some threshold got re-set way too high on attachment security after the hack scare, hopefully our admin can dial that back a bit. These gifs have had zero contact with any Adobe product and have nothing whatsoever to do with "gif89a format.aip" of Adobe Illustrator.
Title: Re: The 2017/2018 freezing season
Post by: LRC1962 on October 15, 2017, 12:36:18 AM
Maybe should start different post, but will ask anyway. Based on projected current path of Hurricane Ophelia:http://www.nhc.noaa.gov/storm_graphics/AT17/refresh/AL172017_5day_cone_no_line_and_wind+png/205031_5day_cone_no_line_and_wind.png (http://www.nhc.noaa.gov/storm_graphics/AT17/refresh/AL172017_5day_cone_no_line_and_wind+png/205031_5day_cone_no_line_and_wind.png)
What is the possible impact on the ESS as to wind/moisture levels on ice formation, or is it possible the dissipation and earlier freezing season will mean little?
Title: Re: The 2017/2018 freezing season
Post by: Shared Humanity on October 15, 2017, 12:41:06 AM
The early freeze is outperforming last years freeze throughout the Arctic with the Greenland Sea being the sole exception with regards to SIE.
Title: Re: The 2017/2018 freezing season
Post by: Shared Humanity on October 15, 2017, 12:44:21 AM
True for area as well.
Title: Re: The 2017/2018 freezing season
Post by: gerontocrat on October 15, 2017, 02:27:32 PM
JAXA DATA
Although JAXA is having a Sunday off, herewith a table and graph up to 13th October. The table shows the large variation in remaining extent gain that happened in recent years.

The graph does show that on average daily extent gain is at maximum at this time, and later settles back a bit. Methinks this is simply a matter of geography, not climate variation. As ice extent reaches more of the Russian shore further extent gain there is impossible.

The graph also shows that for an individual year (e.g. 2016) the average is irrelevant not just for the season but also any day, week or month. Oneself can but watch record and wonder and hope A-Team and his ilk come up with the goods.
Title: Re: The 2017/2018 freezing season
Post by: A-Team on October 15, 2017, 03:22:53 PM
Quote
Pavel notes on #187: Cryosat has resumed. don't see any 3m or thicker ice and there's very little of thicker than 2.5m ice
This is a difficult data set to work with; taking a quick look at netCDF file offered on the CPOM web page (1st image below), the data was there but not in a form (Geo2D) that would allow redrawing the ice thickness map at a larger scale without the lat lon overlays.

Panoply was able to draw out the thickness observations (which seem to be head-to-tail abutted swaths over a month of orbits) and the standard deviations (2nd image). It would be possible to export the thickness numbers to excel to plot the thickness distribution (but what to do about negative ice thicknesses?). Other forums provide very knowledgable posts on Cryosat data and how to compare it to model data such as Piomas.

As the satellite completes a full cycle of its near-polar orbits, the swaths overlap in some places but don't quite come together elsewhere. I looked at several methods of filling in the gaps in ice thickness that would utilize nearby measured thicknesses before settling on D Tschumperlé's graphical algorithm in the Repair section of online G'mic, an amazing French site that allows visitors to conduct a full range of graphical manipulations over the web.

The infill came out rather nice, though it's hard to say how it would compare to kriging or other numeric estimations, much less to the real situation on the ice (which we will never know as this time frame has passed on by).

http://www.cpom.ucl.ac.uk/csopr/seaice.html (http://www.cpom.ucl.ac.uk/csopr/seaice.html)
https://gmicol.greyc.fr (https://gmicol.greyc.fr)
Title: Re: The 2017/2018 freezing season
Post by: Neven on October 15, 2017, 10:22:42 PM
Some threshold got re-set way too high on attachment security after the hack scare, hopefully our admin can dial that back a bit. These gifs have had zero contact with any Adobe product and have nothing whatsoever to do with "gif89a format.aip" of Adobe Illustrator.

I don't know if anything got re-set, but here are the attachment settings I can adjust as admin:
Title: Re: The 2017/2018 freezing season
Post by: Pavel on October 15, 2017, 11:56:23 PM
The Arctic atmosphere tries to cool but it fails. According to the weather forecasts no significant coldness will come or even things may get warmer
Title: Re: The 2017/2018 freezing season
Post by: A-Team on October 16, 2017, 05:58:11 PM
Quote
According to the weather forecasts no significant coldness will come or even things may get warmer
Here is the ESRL forecast out to Oct 24th for 80ºN. Forty 2m air temperature maps are provided at 6hr intervals and the average determined. The identical result is displayed in a variety of color tables with a scale that runs from -22º to +6º C. These variations illustrate how interpretations can be helped or hindered by presentation choices.

 Warmer air appears to be intruding well into the interior from the North Atlantic though the CAA remains cold. However it is not warm enough to melt any snow on ice. This time of year, snow retards bottom ice formation by insulating the top ice from air.

The second animation shows these temperatures for the Arctic Ocean as a whole over the same time frame. This shows air flow well but it is not easy to get a sense of the time-averaged temperature from it. The averaged whole ocean temperature has a red line indicating the southern boundary of sea water above its freezing temperature of -1.8ºC

Technical note: Panoply was run in linear grayscale mode on REB.2017-10-15.nc. The 40 frames are then averaged to a single grayscale in Gimp. All extraneous pixels are removed, leaving only the image plus its palette as 256 grays. Lookup tables in ImageJ are applied, those that seem informative are saved as .png, reloaded as an ImageJ stack, and saved out as a gif. Gimp has a bad bug in gifs that causes it to seek a global color table whereas gif89 allows each frame to have its own color table. The cluts used here are gray, glow, redHot, ICA3, physics, royal, rainbow, rire, cool, and inverted glasbey with the addition of G'mic contouring in some instances.
Title: Re: The 2017/2018 freezing season
Post by: A-Team on October 18, 2017, 09:46:40 AM
It's that time of year again, when thousands of abstracts for AGU meeting become available. Hardly anyone discloses results, posters aren't available for poster sessions, talks won't be videoed, their powerpoints won't be archived, and already-published articles won't be linked.

Still, AGU17 does allow a look ahead to the coming year of journal articles. A name search can show what a particular scientist has been up to; for example Neven asked upforum what J Stroeve is doing, she is on three of the abstracts.

https://agu.confex.com/agu/fm17/meetingapp.cgi/SearchResults/0 (https://agu.confex.com/agu/fm17/meetingapp.cgi/SearchResults/0)

Snow on Arctic sea ice is an active topic. Like ice thickness and clouds, it is very difficult to characterize basin-wide, in part because depth alone doesn't capture its insulating properties in freeze season: it's blown into windrows, it may be dunked in sea water on a floe with negative freeboard, or be rained upon and refreeze. Still, it looks like some better products than what we have now may be in the pipeline.

C23E-08: Merging observations and reanalysis data to improve estimates of snow depth on Arctic sea ice
NT Kurtz et al

Snow is an important controlling factor in the heat and radiation balance of the Arctic sea ice pack. Knowledge of snow on sea ice is also required for retrievals of sea ice thickness from airborne and spaceborne altimeters, and is presently the largest source of uncertainty in the conversion of freeboard to sea ice thickness from these altimetry data.

Multiple sources of observational snow depth data exist such as those from the Operation IceBridge (OIB) snow radar, passive microwave satellites, and ice mass balance buoys. However, these observational data sources are limited in spatial and/or temporal extent, which makes their usage impractical when used for basin-wide sea ice thickness retrievals in a standalone fashion.

We show how the use of snow depth observations from the OIB snow radar can be used as a primary means to improve basin-scale snow depth results from a simple snow model forced by reanalyses and satellite-derived ice drift estimates. We also show how different observational data sets impact the snow depth estimates, and how best to incorporate data sets of differing temporal and spatial scales to provide snow thickness estimates of consistent quality over the entire sea ice growth season. Particular focus is given to the new 2017 OIB data set which included new flights into the eastern Arctic sector where interesting differences were seen between the first year and multiyear ice areas.

C32B-02: Snow accumulation on Arctic sea ice: is it a matter of how much or when?
M Webster  et al

Snow on sea ice plays an important, yet sometimes opposing role in sea ice mass balance depending on the season. In autumn and winter, snow reduces the heat exchange from the ocean to the atmosphere, reducing sea ice growth. In spring and summer, snow shields sea ice from solar radiation, delaying sea ice surface melt. Changes in snow depth and distribution in any season therefore directly affect the mass balance of Arctic sea ice.

In the western Arctic, a decreasing trend in spring snow depth distribution has been observed and attributed to the combined effect of peak snowfall rates in autumn and the coincident delay in sea ice freeze-up. Here, we present an in-depth analysis on the relationship between snow accumulation and the timing of sea ice freeze-up across all Arctic regions.

A newly developed two-layer snow model is forced with eight reanalysis precipitation products to: (1) identify the seasonal distribution of snowfall accumulation for different regions, (2) highlight which regions are most sensitive to the timing of sea ice freeze-up with regard to snow accumulation, and (3) show, if precipitation were to increase, which regions would be most susceptible to thicker snow covers. We also utilize a comprehensive sensitivity study to better understand the factors most important in controlling winter/spring snow depths, and to explore what could happen to snow depth on sea ice in a warming Arctic climate.

C33C-1215: Rainy Days in the New Arctic: A Comprehensive Look at Precipitation from 8 Reanalysis
L Boisvert  et al

Precipitation in the Arctic plays an important role in the fresh water budget, and is the primary control of snow accumulation on sea ice. However, Arctic precipitation from reanalysis is highly uncertain due to differences in the atmospheric physics and use of data assimilation and sea ice concentrations across the different products. More specifically, yearly cumulative precipitation in some regions can vary by 100-150 mm across reanalyses. This creates problems for those modeling snow depth on sea ice, specifically for use in deriving sea ice thickness from satellite altimetry.

In recent years, this new Arctic has become warmer and wetter, and evaporation from the ice-free ocean has been increasing, which leads to the question: is more precipitation falling and is more of this precipitation rain? This could pose a big problem for model and remote sensing applications and studies those modeling snow accumulation because rain events will can melt the existing snow pack, reduce surface albedo, and modify the ocean-to-atmosphere heat flux via snow densification.

In this work we compare precipitation (both snow and rain) from 8 different reanalysis: MERRA, MERRA2, NCEP-R1, NCEP-R2, ERA-Interim, ERA-5, ASR and JRA-55. We examine the annual, seasonal, and regional differences and compare with buoy data to assess discrepancies between products during observed snowfall and rainfall events. Magnitudes and frequencies of these precipitation events are evaluated, as well as the “residual drizzle” between reanalyzes. Lastly, we will look at whether the frequency and magnitude of “rainy days” in the Arctic have been changing over recent decades.

C21B-1122: Synoptic weather conditions, clouds, and sea ice in the Beaufort and Chukchi Seasonal Ice Zone
Z Liu et al
http://journals.ametsoc.org/doi/abs/10.1175/JCLI-D-16-0887.1 (http://journals.ametsoc.org/doi/abs/10.1175/JCLI-D-16-0887.1)

The connections between synoptic conditions and clouds and sea ice over the Beaufort and Chukchi Seasonal Ice Zone are examined. Four synoptic states with distinct thermodynamic and dynamic spatial and vertical signatures are identified using a k-means classification algorithm and the ERA-Interim reanalysis data from 1979 to 2014.

The combined CloudSat and Calipso cloud observations suggest control of clouds by synoptic states. Warm continental air advection is associated with the fewest low-level clouds, cold air advection under low pressure generates the most low-level clouds. Low-level cloud fractions are related to lower-tropospheric stability and both are regulated by synoptic conditions. Observed cloud vertical and spatial variability is reproduced well in ERA-Interim, but winter low-level cloud fraction is overestimated.

Sea ice melt onset is related to synoptic conditions. Melt onsets occur more frequently and earlier with warm air advection states. The warm continental air advection state with the highest temperature is the most favorable for melt onsets even though fewer low-level clouds are associated with this state. The other warm advection state is cloudier but colder.

In the Beaufort and Chukchi Seasonal Ice Zone, the much higher temperature and total column water of the warm continental air advection state compensate the smaller cloud longwave radiative fluxes due to the smaller low-level cloud fraction. In addition, the higher shortwave radiative fluxes and turbulent fluxes to the surface are also favorable for sea ice melt onset.

C21G-1186: There goes the sea ice: following Arctic sea ice parcels and their properties.
MA Tschudi et al
http://www.mdpi.com/2306-5729/2/3/25 (http://www.mdpi.com/2306-5729/2/3/25)

Arctic sea ice distribution has changed considerably over the last couple of decades. Sea ice extent record minimums have been observed in recent years, the distribution of ice age now heavily favors younger ice, and sea ice is likely thinning. This new state of the Arctic sea ice cover has several impacts, including effects on marine life, feedback on the warming of the ocean and atmosphere, and on the future evolution of the ice pack.

The shift in the state of the ice cover, from a pack dominated by older ice, to the current state of a pack with mostly young ice, impacts specific properties of the ice pack, and consequently the pack’s response to the changing Arctic climate. For example, younger ice typically contains more numerous melt ponds during the melt season, resulting in a lower albedo. First-year ice is typically thinner and more fragile than multi-year ice, making it more susceptible to dynamic and thermodynamic forcing.

To investigate the response of the ice pack to climate forcing during summertime melt, we have developed a database that tracks individual Arctic sea ice parcels along with associated properties as these parcels advect during the summer. Our database tracks parcels in the Beaufort Sea, from 1985 – present, along with variables such as ice surface temperature, albedo, ice concentration, and convergence.

We are using this database to deduce how these thousands of tracked parcels fare during summer melt, i.e. what fraction of the parcels advect through the Beaufort, and what fraction melts out? The tracked variables describe the thermodynamic and dynamic forcing on these parcels during their journey. The attached image (it’s not) shows the ice surface temperature of all parcels (right) that advected through the Beaufort Sea region (left) in 2014.

C33C-1210: Towards development of an operational snow-on-sea-ice product
GE Liston et al

While changes in the spatial extent of sea ice have been routinely monitored since the 1970s, less is known about how the thickness of the ice cover has changed. While estimates of ice thickness across the Arctic Ocean have become available over the past 20 years based on data from ERS-1/2, Envisat, ICESat, CryoSat-2 satellites and Operation IceBridge aircraft campaigns, the variety of these different measurement approaches, sensor technologies and spatial coverage present formidable challenges. Key among these is that measurement techniques do not measure ice thickness directly – retrievals also require snow depth and density.

Towards that end, a sophisticated snow accumulation model is tested in a Lagrangian framework to map daily snow depths across the Arctic sea ice cover using atmospheric reanalysis data as input. Accuracy of the snow accumulation is assessed through comparison with Operation IceBridge data and ice mass balance buoys (IMBs). Impacts on ice thickness retrievals are further discussed.
Title: Re: The 2017/2018 freezing season
Post by: A-Team on October 18, 2017, 12:15:22 PM
Here are those same three RASM-ESRL precipitation forecasts at 24 hour intervals out to Oct 24th. A moderate amount of rain-on-snow is foreseen for a small area north of Svalbard. Snow depth is moderate, at most 0.25m, and quite uneven in providing thermal insulation after wind-blown drifting is considered (2nd image),
Title: Re: The 2017/2018 freezing season
Post by: Neven on October 18, 2017, 02:31:44 PM
Snow on Arctic sea ice is an active topic. Like ice thickness and clouds, it is very difficult to characterize basin-wide, in part because depth alone doesn't capture its insulating properties in freeze season: it's blown into windrows, it may be dunked in sea water on a floe with negative freeboard, or be rained upon and refreeze. Still, it looks like some better products than what we have now may be in the pipeline.

Thanks for those abstracts, A-Team. Very interesting stuff. Snow on ice is one of those things I'd always known about, but my interest in it really got kindled during this past melting season.

A couple of days ago I also received this interesting message in my mailbox:

Quote
Dear colleagues and sea ice friends,

POLAR2018 is a *unique**joint event* organized by the Scientific
Committee on Antarctic Research SCAR and the International Arctic
Science Committee IASC, which will take place in Davos, Switzerland,
from 15 - 26 June 2018 with the open science conference from 19 - 23
June; see http://www.polar2018.org (http://www.polar2018.org) for general information.

Following up with our first invitation on September 27 we would like to
encourage you to submit your presentation to the conference session
entitled "*The role of snow on sea ice for sea-ice parameter retrieval
and variability*".

We invite studies dealing with in situ observations, with retrieval from
satellite observations, modeling and combinations thereof for snow
parameters on sea ice. We also invite studies on methods for quantifying
the influence of (unknown) snow properties on the satellite retrieval of
sea-ice parameters, on reducing the noise, improving the accuracy of
retrieved sea-ice parameters due to snow properties, and related studies.

Conveners of this session are: Stefan Kern, Burcu Ozsoy, Georg Heygster and Leif T. Pedersen

Please find details about the program as well as deadlines here:
http://www.polar2018.org/program.html (http://www.polar2018.org/program.html)
Title: Re: The 2017/2018 freezing season
Post by: A-Team on October 18, 2017, 09:12:41 PM
Quote
unique event which will take place in Davos, Switzerland
I am skipping both Bilderberg and Davos this year in favor of a staycation. ;) 

The abstracts below speak to common themes on the forum; it's hard to say which will emerge as game-changers vs incremental improvements vs never-to-be-seen-agains.

C21G-1188: Estimation of Melt Ponds over Arctic Sea Ice using MODIS Surface Reflectance Data
Y Ding et al

Melt ponds over Arctic sea ice is one of the main factors affecting variability of surface albedo, increasing absorption of solar radiation and further melting of snow and ice. In recent years, a large number of melt ponds have been observed during the melt season in Arctic. Moreover, some studies have suggested that late spring to mid summer melt ponds information promises to improve the prediction skill of seasonal Arctic sea ice minimum.

In the study, we extract the melt pond fraction over Arctic sea ice since 2000 using three bands MODIS weekly surface reflectance data by considering the difference of spectral reflectance in ponds, ice and open water. The preliminary comparison shows our derived Arctic-wide melt ponds are in good agreement with that derived by the University of Hamburg, especially at the pond distribution. We analyze seasonal evolution, inter-annual variability and trend of the melt ponds, as well as the changes of onset and re-freezing.

The melt pond fraction shows an asymmetrical growth and decay pattern. The observed melt ponds fraction is almost 25% in early May and increases rapidly in June and July with a high fraction of more than 40% in the east of Greenland and Beaufort Sea. A significant increasing trend in the melt pond fraction is observed for the period of 2000-2017.


C21G-1179: A Novel Approach To Retrieve Arctic Sea Ice Thickness For Prediction And Analysis
L Brucker et al

In spite of October-November Arctic-sea-ice-volume loss exceeding 7000 km3 in the decade following ICESat launch, most global ocean reanalysis systems are not able to reproduce such a drastic decline.

Knowledge of the sea ice properties and its thickness distribution is critical to our understanding of polar ocean processes and the role of the polar regions in the Earth's climate system. Existing large-scale sea ice thickness datasets are derived from freeboard observations made by different satellite altimeters (radar and lidar). These datasets are significantly different due to the remote sensing technique and spacecraft orbit, and they are limited in time. These differences increase the difficulty of using such data for sea ice initialization and assimilation, and increase the challenge for studying sea ice processes and interactions with the ocean and atmosphere.

For the first time, we were able to reproduce the Arctic sea ice thickness field at 10 km resolution with success for fall, winter, and spring (April/May depending on melt conditions) from passive microwave data. Our results reveal the same patterns of thickness distribution in the Arctic basin and peripheral seas as CryoSat-2, and the majority of the retrievals are within 0.5 m of CryoSat-2. The range of CryoSat-2 ice thickness is correctly retrieved, including in the upper range (3-5 m). The amplitude is well reproduced too, as the distribution of differences is centered on 0 m (no bias).

Some underestimations are visible between islands of the Canadian Archipelago, but due to the size of the field of view our confidence will always be lower in this region where there is land contamination. An initial comparison of the AMSR2 ice thickness with IceBridge airborne products in different sectors (Beaufort sea, central Arctic) demonstrates the quality of the retrievals.

We will also quantify the prediction and nowcast gain obtained from assimilating these new retrievals. We carried-out the integration of 36 members of coupled NASA Goddard Earth Observing System Model, version 5 (GEOS-5) to enable the implementation of an Ensemble Kalman Smoother (EnKS) over the period September 2012 - January 2013. Assimilating our retrievals improves the nowcast of ice volume, the forecast and the retrospective forecast.


C11D-06: Regional Arctic sea-ice prediction: A direct comparison of potential versus operational seasonal forecast skill
M Bushuk et al

Seasonal predictions of Arctic sea ice on regional spatial scales are a pressing need for a broad group of stakeholders, however, most forecast skill assessments to date have focused on pan-Arctic sea-ice extent (SIE). In this work, we present a direct comparison of potential and operational seasonal prediction skill for regional Arctic SIE. This assessment is based on two complementary suites of seasonal prediction ensemble experiments performed with a global coupled climate model.

First, we assess the operational prediction skill for de-trended regional SIE using a suite of retrospective initialized seasonal forecasts spanning 1980-2017. These retrospective forecasts are found to skillfully predict regional winter SIE at lead times of 3-11 months and regional summer SIE at lead times of 1-4 months, owing partially to subsurface ocean temperature and sea-ice thickness initial conditions, respectively. Second, we present a suite of perfect model predictability experiments with start dates spanning the calendar year, which are used to quantity the potential regional prediction skill of this system.

These perfect model experiments reveal that regional Arctic SIE is potentially predictable at lead times beyond 12 months in many regions, substantially longer than the current operational skill of this system. Both the retrospective forecasts and perfect model experiments display a spring prediction skill barrier for regional summer SIE forecasts, indicating a fundamental predictability limit for summer regional predictions. The skill gap identified in this work indicates a promising potential for future improvements in regional SIE predictions.


C21G-1190: Assessing surface radiative fluxes and developing surface turbulent heat fluxes over Arctic sea ice
M Song et al

In this study, we have developed a new satellite-based surface heat and moisture flux data set over the ice-covered ocean in the Arctic using a recently developed flux algorithm based on the theory of maximum entropy production (MEP model). First, the accuracy and uncertainty associated with surface radiative fluxes and temperature for three available satellite products are evaluated against the assembled in-situ data.

The three satellite products are the Surface Radiation Budget project (SRB), the International Satellite Cloud Climatology Project (ISCCP), and the Extended AVHRR Polar Pathfinder version-2 (APP-x).

Our comparisons suggest that 1) in terms of the overall bias, root mean square error, and correlation, the net surface radiative flux of ISCCP is closer to in-situ observations than that of SRB and APP-x; 2) in terms of the bias by local times, it is not very clear which satellite product is superior to others; and 3) in terms of inter-annual variability of the bias, the net surface radiative flux of ISCCP is more accurate than that of SRB and APP-x. Based on the above comparison, we use the ISCCP surface radiative fluxes as input values for the MEP model to calculate surface turbulent heat fluxes over Arctic sea ice.


C21G-1184: Improving Arctic sea ice edge forecasts by assimilating high resolution VIIRS sea ice concentration data into the U.S. Navy’s ice forecast system
OM Smedstad et al

This study presents the improvement in ice edge error within the U.S. Navy’s operational sea ice forecast system gained by assimilating the high horizontal resolution visible/infrared satellite-derived VIIRS ice concentration products. A series of hindcast studies are performed for the period of 1 January – 31 December 2016 using Global Ocean Forecast System (GOFS 3.1), a 1/12° HYbrid Coordinate Ocean Model (HYCOM) that is two-way coupled to the Community Ice CodE (CICE) in a daily update cycle with the Navy Coupled Ocean Data Assimilation (NCODA).

Comparisons using the VIIRS ice concentration products (< 1km resolution) show lower ice edge location errors than the current system, which assimilates near real-time passive microwave data from the Defense Meteorological Satellite Program (DMSP) Special Sensor Microwave/Imager (SSMIS) and the Advanced Microwave Scanning Radiometer (AMSR2) ice concentration products (25 and 12.5km resolution, respectively).

The daily ice edge locations from the model simulations are compared against independent observed ice edge locations. Results from the Pan-Arctic and regional areas along with seasonal time scales will be presented. A previous study using the Arctic Cap Nowcast/Forecast System (ACNFS), a 1/12° coupled HYCOM/CICE/NCODA for the Northern Hemisphere only, has shown that by assimilating the VIIRS (along with SSMIS and AMSR2) ice concentration products reduced the ice edge location errors by 25% in the pan-Arctic region for the same year-long time period.
Title: Re: The 2017/2018 freezing season
Post by: A-Team on October 18, 2017, 11:31:33 PM
Speaking of snow depth, here is another ESRL product, snowdepthchange.gif from their web page or archival REB_plots. It is somewhat peculiar in that D0 is not provided, only the D5 forecast. Thus the animation is of these day fives -- 15 Sep to 22 Oct -- rather than the presumably more accurate initial states.

Still, it gives an idea how rapidly snow depth changes from day to day as well as the expected prevailing wind. The final frame averages these out, even though the palette is not really designed to support this.

This time of year, when thermal insulation not solar insolation is the issue for the rate of bottom ice growth induced by frigid surface air, the relevant property of snow is its conductivity.

Is it still, as often assumed, a uniform basin-wide porous medium with a large immobilized air component (like a foam pad) after being blown around for weeks, possibly getting dunked, rained on, and soaked with sea spray? If so, is the current ankle-deep mean snowpack enough to seriously inhibit bottom growth, relative to not-so-cold prevailing mean air temperatures?

That's hard to say directly with no buoys, no ships, and no one out there but satellites can measure bulk properties. The scale though is not commensurate with that of snow features, though Sentinel-1 comes fairly close.

http://www.inscc.utah.edu/~campbell/snowdynamics/reading/Pomeroy.pdf
http://acwc.sdp.sirsi.net/client/search/asset/1005644;jsessionid=CE14DA1FFAEF3D6FD98ABAD517B04B81.enterprise-15000
http://www.sciencedirect.com/science/article/pii/S0165232X1100187X
http://arc.lib.montana.edu/snow-science/objects/issw-1994-176-184.pdf
Title: Re: The 2017/2018 freezing season
Post by: Peter Ellis on October 19, 2017, 10:58:44 AM
Speaking of snow depth, here is another ESRL product, snowdepthchange.gif from their web page or archival REB_plots. It is somewhat peculiar in that D0 is not provided, only the D5 forecast.

Given that it's a depth change, then surely it has to be estimated over a given period?  At D0, there is no change from D0...

Images for the absolute values of snow/ice thickness and area are in one tab, images for the 5-day changes are in another.
https://www.esrl.noaa.gov/psd/forecasts/seaice/


Edit to add: Moreover, given that the "5 day change" values from two successive days' forecasts will necessarily include four out of the same 5 days, then I think rapid changes from day to day may be more indicative of model variability than anything to do with actual weather.
Title: Re: The 2017/2018 freezing season
Post by: A-Team on October 19, 2017, 06:37:53 PM
Right. ESRL is primarily interested in making forecasts whereas we are primarily interested in archival initial state time series because short-term predictions have such a limited shelf life. The idea here was to finish scrolling through all their precipitation products to see which are worth scripting (Panoply --> ImageMagick --> cloud --> forum) into hindcasts + today + forecast time series.

The ESRL web site presents this one well enough, though too large to display well here. It might be of heads-up interest should more moisture-laden storm sweeps north from the Caribbean again this fall. However ice thickening takes place on a much slower time scale, so daily comings and goings of the insulating blanket of snow are of less interest than mean snowpack.

While it's hard to see the thermal relevance of blowing ankle-deep snow to bottom ice formation rates, maybe it will be knee-deep by late winter and suppress early melt pond formation through reflectance.

There being little purpose in simply replicating daily changes in NOAA's web site, the question becomes where we can 'add value'. Among the many opportunities explored in previous posts (eg SMOS-ESRL thin ice hybrids), are combined time series across the three ESRL (and other) archives.

These can be seasonal: the forecast below combines an open water property with a sea ice measure, namely temperature. That product diminishes in utility along with residual exposed water later in the fall. Salinity is another option; it mixes SMOS bulk ice salinity with that of ESRL open water. That too is seasonal since UH SMOS availability is melt-limited.

Note the Chukchi north of the Bering Strait is still far too warm for ice to form. That stayed open to mid-December last year. The map also shows a pronounced intrusion of warm surface water in the Yermak Plateau area north of Svalbard. Spurious open water is shown around CAA islands which are very difficult to get at accurately with gridded data (UH AMSR3 3.125 km is a better option there).

Technical note: these are easy to make since 'not sea ice' on the sea ice layer provides a pixel-perfect cut-out allowing any open water characteristic to show through. As long as the data sources are both available to Panoply as netCDF files, Gimp will receive the maps in perfect co-registration with compatible and operable palette legends. This readily scales to times series via tile 'n' slice.
Title: Re: The 2017/2018 freezing season
Post by: A-Team on October 19, 2017, 10:54:01 PM
Here are 27 days of sea water salinity from RASM-ESRL for October. As noticed before, each ten day forecast series begins at hour 24 rather than hour 00, the initial state. (Some even start at hour 48, skipping the first two days.) The odd boundary on the Svalbard side apparently results from a lack of data (or maybe it's off-scale on the high side).

There's ample room in a netCDF file for an explanation of the satellite (or oceanographic) source of the data but there is none. It's not clear what salinity under the ice pack means in terms of depth. The salinity range is also mistakenly set, showing large negative salinities.

Indeed, the whole file system of this project is seriously mis-configured. File names for a given product are all the same; they're supposed to be inseparably concatenated with their date. The daily RASM-ESRL archive is presented as nine separate files but these in effect just represent an animatable time sequence. They could have been folded into a single file with each time an animation frame (and there's a simple command line for doing just that).

This project reminds me of an autonomous 18-wheeler driving without incident from NY to LA but continuing on, only to plunge off the Santa Monica pier. That is, is anyone really driving this project, who is using it without reporting the flat tires, and how long can it run on fumes without  interventional refueling?

Whatever, it's interesting to watch salinity evolve along the Alaskan and East Siberian coasts. Salinity lowers the freezing point of sea water somewhat but here it is not determinative because though the remaining open water is fresher, its temperature (and that of the air above) are warmer.

SMOS provides bulk ice salinity of the ice pack surface which is more or less directly observable from its dielectric. As sea ice ages, it extrudes its brine which lowers its perceived bulk salinity here.
Title: Re: The 2017/2018 freezing season
Post by: Michael on October 20, 2017, 11:08:31 AM
Here are 27 days of sea water salinity from RASM-ESRL for October. As noticed before, each ten day forecast series begins at hour 24 rather than hour 00, the initial state. (Some even start at hour 48, skipping the first two days.) The odd boundary on the Svalbard side apparently results from a lack of data.

The "t024" / "t48" indicate "hours since analysis" (Tau) rather than a time period.

Quote
variables:
   double tau ;
      tau:long_name = "Tau" ;
      tau:units = "hours since analysis" ;
   double time(time) ;
      time:long_name = "Valid Time" ;
      time:units = "hour since 2000-01-01 00_00_00" ;
   double time_bounds(time, d2) ;
      time_bounds:long_name = "boundaries for time-averaging interval" ;
      time_bounds:units = "days since 0000-01-01 00:00:00" ;
data:

 tau = 24 ;
 time = 155856 ;
 time_bounds =
  736488.75, 736489 ;

"time" in the RASM-ESRL files is calendar hours, "time" in the REB files is model days ("All years have exactly 365 days").

These data in the RASM-ESRL files are the same as the fourth set of data in the REB files but converted from float to short, in the process removing the Nans.
Title: Re: The 2017/2018 freezing season
Post by: A-Team on October 20, 2017, 04:51:05 PM
Thanks. You are talking about ice and snow thicknesses?

Salinity, compressive strength, sea water temperature, the three melts, and two precips are not to be found in REB. None of these are attributed within RASM_ESRL. Their model might be able to derive some from others but salinity, water temperature and so on must be external inputs. From where though, there might be something better out there that could be stubbed in.

The REB files overlap do considerably in name. And they do provide start-stop ranges. However they provide 40 animation frames, the first of which I've been taking as t00 whereas RASM_ESRL provide only 9.

So I'm not sure what you mean by same as every 4th bit of data is the same. That would only use up 4x9 = 36 (sometimes 4x8 = 36) of the 40, suggesting the initial (or final?) state is missing in RASM_ESRL. Or rather, the latter uses intervals, n times has n-1 intervals but what does this mean in tangible terms for observational validation or animation frames, very little.

It seems better just to use REB whenever possible since they didn't see the merge app as applicable to RASM_ESRL intervals. But REB doesn't have the data to generate all the forecast animations that RASM_ESRL can. No way am I going to interpolate four 6hr frames out of one 24 hour to complete the file set in REB.

NaNs, float etc seem to be non-issues suppressed by Panoply and have no impact on visualizations or grepped csv coming out of ncdump.

It appears that not nearly enough information is provided in RASM_ESRL and REB.nc together to draw all the REB plots. That's unfortunate, those files might have been provided so users could correct the many inept products provided in REB plots, make omitted ones, compare to other observational sources, run an alternative model, or compare to competitive products like ECMWF. 

NOAA states this project is experimental. Fair enough but in its 3rd year, it's time to pull things together, maybe lay on some documentation and make the five minute fixes. It's true though that they didn't need to provide a public archive at all, much less the most thorough one around providing comprehensive Arctic forecasts. Expired forecasts have such limited interest that the real value may lie in archival initial states (or their reanalysis), which need attending to before letting this go on as unattended robo-ware.

Going around the web to the netCDF data sources we commonly use for forum graphics, I see a tremendous range in quality from zero (take this map and shove it), outdated (defective variable treatment disabling Geo2D), inadequately commented files, okay, and fantastic. In the instances where I know the authors, there's been a perfect correlation of open sourcing effort with the quality of their journal publications.

Data is not open source accessible in my view if it can't be viewed and manipulated without purchasing proprietary software, working in terminal mode, or emailing a deceased author. Site users and journal readers should have the capacity in most instances to reproduce major graphics.

I see a goodly number of totally incompetent graphical products, both in archives and after peer review. That is the real purpose of posting netCDF files -- the next person who comes along might have the skills to fix the graphic, re-project or re-palette it, delete over-writing  layers, test it for accuracy, or combine it in novel ways with other data sources. There is no purpose to climate science if it is not communicated.

In every collaborative project I've worked on, everyone including myself had moved on and lost all interest long before the draft worked its way through the publication process. We all knew what was in the data, making derivative charts from it was considered a total bore, the only thing worse being a remake six months later. Here again it's in everyone's interest to have a proper archive.

Other scientific communities with even bigger data sets, such as genomics, laid down the law fifteen years ago (GenBank) and enforce it via conditions in the grant (both govt and foundation). There was a lot of initial resistance to sharing, people acted like they somehow 'owned' the data even though the public had bought and paid for every scrap of it with the understanding they could see it.

Nobody has to share: just click the 'Don't Accept' option on the grant application, do the work at home, pay for it out of your non-salaried savings, and post on your facebook page to sidestep journal data requirements. If you don't go that route, then an adequate open archive is, scientifically speaking, obligatory. And it's especially important in the case of climate change.
Title: Re: The 2017/2018 freezing season
Post by: Michael on October 21, 2017, 10:46:50 AM
So I'm not sure what you mean by same as every 4th bit of data is the same. That would only use up 4x9 = 36 (sometimes 4x8 = 36) of the 40, suggesting the initial (or final?) state is missing in RASM_ESRL. Or rather, the latter uses intervals, n times has n-1 intervals but what does this mean in tangible terms for observational validation or animation frames, very little.

Apologies, this is very much off topic.

My explanation. was very poor.  If the first file in the RASM-ESRL archive is labeled t048 it simply means that the ensemble hasn't been run and and the previous day 2 has been carried forward as day 1 etc.

To get the relationship between the RASM-ESRL and REB files, I would suggest extracting the relevant data from all the RASM-ESRL files in an archive and comparing it with the same data from the corresponding REB file.

ncdump -v tau,time,time_bounds "RASM-ESRL_2017-10-dd-00_t0hh.nc" > RASM-ESRL201710ddhh.txt
ncdump -v time,time_bounds "REB.2017-10-dd.nc" > REB20171010time.txt

To convert RASM-ESRL "time" to REB "time" :  time =  (time + 17519880) / 24

The actual source for the data in the individual .nc files can be found near the bottom of the history section of the header.
The syntax is ncrcat -v [variable list] [source files] [ouput files]
and ncks -v [variable list] [source file] [ouput files]
Title: Re: The 2017/2018 freezing season
Post by: Feeltheburn on October 21, 2017, 09:09:14 PM

Yes, there is substantially more Arctic sea ice extent now than there was on this same day last year. But it should be noted that the NSIDC ASIE increase of 1.038 km2 since October 1 is less than that measured in 2015, 2014, 2013, 2012, or 2010. Month-to-date, NSIDC SIE is still running below the ten-year average, and year-to-date, 2017 extent is deeply entrenched in second place. Bottom line, then: I'm not sure how "nicely" once can say it's recovering.

As of October 20, 2017, the SIE is running *ahead* of the 10-year average (2007 to 2016) and is currently in "5th place" behind 2007, 2016, 2011, and 2012, and has just about caught up with, and may soon surpass, 2009.

Update:

NSIDC SIE - October 20

Year          SIE (million km2)         Rank (for 11 year period)             2017 vs Year

2007         6.279                                1st                                       +958,000 km2
2008         8.026                                11th                                      -789,000 km2
2009         7.307                                6th                                           -7,000 km2
2010         7.508                                7th                                        -271,000 km2
2011         6.496                                3rd                                       +741,000 km2
2012         6.582                                4th                                       +655,000 km2
2013         7.992                                10th                                      -755,000 km2
2014         7.805                                9th                                        -568,000 km2
2015         7.548                                8th                                        -311,000 km2
2016         6.310                                2nd                                      +927,000 km2
2017         7.237                                5th                                                   0 km2

10-Year Average (2007 through 2016) = 7.185 km2

2017 vs 10 year average 2007 to 2016: +51,700 km2

Given the very poor start that 2017 had (the worst ever), I think it's accurate to say that 2017 has rebounded nicely, and better than almost anyone expected. Someone showed the predictions in the SIE surveys for NSIDC and Jaxa, and almost everyone predicted way low, suggesting deeply engrained negative bias. My predictions were just about dead on for all surveys. That is not to brag. Far from it. I come with no experience compared to most here. But I am also not weighed down by negative bias. I just look at the data and then make my predictions.
Title: Re: The 2017/2018 freezing season
Post by: Feeltheburn on October 21, 2017, 09:16:50 PM
The 2017 global sea ice extent trend line is at a point where it has to decide whether it will join the pack of trend lines, or tag along with the 2016 trend line:

I think the decision has been made. Arctic sea ice is now in 5th place for past 11 years, and Antarctic sea ice is no longer in last place, but 3rs place according to published graph. So it stands to reason the composite graph line should be trending upward with the pack.
Title: Re: The 2017/2018 freezing season
Post by: Feeltheburn on October 21, 2017, 09:20:59 PM
The 2017 global sea ice extent trend line is at a point where it has to decide whether it will join the pack of trend lines, or tag along with the 2016 trend line:

Here are the graphs, showing the decision has been made to stay with the pack.

https://sites.google.com/site/arctischepinguin/home/sea-ice-extent-area/grf/nsidc_global_area_byyear_b.png

https://sites.google.com/site/arctischepinguin/home/sea-ice-extent-area/grf/nsidc_global_extent_byyear_b.png
 :D
Title: Re: The 2017/2018 freezing season
Post by: Jim Pettit on October 22, 2017, 02:21:40 PM
As of October 20, 2017, the SIE is running *ahead* of the 10-year average (2007 to 2016) and is currently in "5th place" behind 2007, 2016, 2011, and 2012, and has just about caught up with, and may soon surpass, 2009.

Update:

NSIDC SIE - October 20

Year          SIE (million km2)         Rank (for 11 year period)             2017 vs Year

2007         6.279                                1st                                       +958,000 km2
2008         8.026                                11th                                      -789,000 km2
2009         7.307                                6th                                           -7,000 km2
2010         7.508                                7th                                        -271,000 km2
2011         6.496                                3rd                                       +741,000 km2
2012         6.582                                4th                                       +655,000 km2
2013         7.992                                10th                                      -755,000 km2
2014         7.805                                9th                                        -568,000 km2
2015         7.548                                8th                                        -311,000 km2
2016         6.310                                2nd                                      +927,000 km2
2017         7.237                                5th                                                   0 km2

Of course, I wasn't using single-day numbers; I specifically referred to longer time scales, which are more "truthful". And those long-term scales show that October-to-date NSIDC SIE growth is running below the ten-year average; October 2017 has seen less ice growth than that measured in 2008, 2010, 2012, 2013, 2014, or 2015. So, again: hard to call that a "nice" recovery. But, you know, whatever makes you happy.

Someone showed the predictions in the SIE surveys for NSIDC and Jaxa, and almost everyone predicted way low, suggesting deeply engrained negative bias.

Oh, is that what it "suggests"? Personally, I think that's insulting and dismissive. But let's go with it anyway. So, then, when you have in the past predicted more ice than there actually turned out to be, can we assume you were exhibiting a "deeply engrained positive bias"? Or does it actually simply suggest that the majority of the people here, most who know far more about Arctic ice than either you or I ever will, made the best, most accurate predictions they could based on the available data and observations?

My predictions were just about dead on for all surveys. That is not to brag. Far from it. I come with no experience compared to most here. But I am also not weighed down by negative bias. I just look at the data and then make my predictions.

I'll have my grandmother bake you a cookie.
Title: Re: The 2017/2018 freezing season
Post by: A-Team on October 22, 2017, 05:26:35 PM
Quote
my predictions were perfect
Preposterous. Without some idea of what the weather is going to do a few months to a year out, it's just numerology trending off hindcasts. No one had or has the slightest idea where the weather is going, least of all you.

The basic idea in measuring 'forecast skill' is assigning a baseline score of 0.00 to physics-free continuation. Thus I can predict with very high confidence that the weather in Tucson AZ will be sunny on 22 Oct 2025 but the skill there is 0.00 because it's been like that for centuries.

To get a grasp on just how incredibly complicated it is to make real predictions, try reading this article on k-means synoptic states over the Beaufort-Chukchi. The cloud component alone is extremely difficult yet is very important all year long to sea ice extent and thickness for seasonally different reasons.

Can you share with us where you got the necessary data for this summer?  Cloudsat is essential for prediction but it broke a reaction wheel on June 4th and went into standby mode, not sending any more data down. The problems with Cloudsat and Calypso data are all but intractable even when they are operational; no one here has ever made any headway with the CSU data repository.

The best that can be hoped for is some rules of thumb will emerge that provide some after-the-fact understanding:

Synoptic Conditions, Clouds, and Sea Ice Melt Onset in the Beaufort and Chukchi Seasonal Ice Zone
Z Liu, A Schweiger APL UW

Cloud response to synoptic conditions over the Beaufort and Chukchi seasonal ice zone is examined. Four synoptic states with distinct thermodynamic and dynamic signatures are identified using ERA- Interim reanalysis data from 2000 to 2014.

CloudSat and CALIPSO observations suggest control of clouds by synoptic states. Warm continental air advection is associated with the fewest low-level clouds, while cold air advection generates the most low-level clouds. Low-level clouds are related to lower-tropospheric stability and both are regulated by synoptic conditions.

High-level clouds are associated with humidity and vertical motions in the upper atmosphere. Observed cloud vertical and spatial variability is reproduced well in ERA-Interim, but winter low-level cloud fraction is overestimated. This suggests that synoptic conditions constrain the spatial extent of clouds through the atmospheric structure, while the parameterizations for cloud microphysics and boundary layer physics are critical for the life cycle of clouds in numerical models. Sea ice melt onset is related to synoptic conditions.

Melt onsets occur more frequently and earlier with warm air advection. Synoptic conditions with the highest temperatures and precipitable water are most favorable for melt onsets even though fewer low-level clouds are associated with these conditions.

Quote
[Already by 2014, it had been shown] synoptic patterns better explain the variability of sea ice than climate indices such as the Arctic Oscillation, the North Atlantic Oscillation and the Arctic dipole.
These are in effect rudimentary synoptic patterns: for example the daily AO index is constructed by projecting the daily 1000mb height anomalies poleward of 20°N onto its loading pattern, the leading mode of Empirical Orthogonal Function (basis states) of monthly mean 1000mb height during 1979-2000 period.
 
http://www.cpc.ncep.noaa.gov/products/precip/CWlink/daily_ao_index/ao.loading.shtml
=-=-=-=-=

Meanwhile, back to ESRL's modest but already ambitious day 10 forecasts and whether they're useful for winter ice thickness growth (which we need for melt season preconditioning). There was a computer mishap resulting in no data for Oct 20th affecting all three archive sections. [This got fixed by the 23rd.] This happened previously on Sept 12th. REB_plots had a glitch on the 16th and so on. To enumerate these, just look down file list for size anomalies.

There's no going back, so the practical impact will be a small but permanent gaps in the initial state time series. That is no different from UH AMSR2 and all the other product archives. In the animations up-forum, the gaps are filled with a duplicate frame from the day before (or if multi-day, from above and below). It is feasible to interpolate within Panoply but with the ice edge moving and so forth, the accuracy is problematic whereas a stalled frame conveys the notion of missing data.
Title: Re: The 2017/2018 freezing season
Post by: Sterks on October 23, 2017, 12:05:17 PM
Given the very poor start that 2017 had (the worst ever), I think it's accurate to say that 2017 has rebounded nicely, and better than almost anyone expected.

I agree with this statement. A rebound that most probably places the <1 mkm2 event beyond 2020.
Title: Re: The 2017/2018 freezing season
Post by: A-Team on October 23, 2017, 02:52:11 PM
Quote
most probably places the <1 mkm2 event beyond 2020.
The same rubbish every fall, catastrophism after low years, recovery chatter after upticks. What could possibly serve as a scientific basis for a 4+ year weather-ocean-ice forecast? In some ways, 2007 was the most disturbing year to date; neither it nor 2012 were foreseen or foreseeable.

Very few of our registrants seem to take any substantive interest in the 2017/18 freezing season, the topic of this forum. Sharing of ungrounded speculation and personal hunches is very boring. Maybe we should just shut it down and come back in May. Visitation levels don't justify the effort.

SMOS 3.1 thin ice thickness is an interesting way to track the season though. If ice doesn't thicken much during the winter (as expected from Arctic amplification), there's that much less to melt during the melt season. Thinner ice also responds very differently to wind dispersion and export.

The first animation compares newly formed ice from 2012-2017 for the 21st of October; there's quite a bit of variability. The still image shows the same years side by side. The bottom animation computes the six year average for this date and flickers 2017 over it.

Whole Arctic trend-lining is far less informative than regional trend-lining, itself little done on our forums even though wipneus posts the necessary data. 2D maps take regional trend-lining to its end state, the resolution of the data. As there's no physical basis for drawing 'Beaufort' or 'Chukchi' boundaries etc, maps can show what is going on free of nomenclatural bias. To first order, that is latitudinal freeze-up about the cold pole (rather than the north pole).

SMOS in a sense integrates all the heat fluxes between atmosphere, newly forming ice and ocean. Since the weather has been so uneventful for so long, bottom growth prediction for older ice will have fewer problems than in past years. The interest right now is the date of final freeze-over, which is going rather slowly in the Beaufort-Chukchi-ESAS regions and unremarkably above Svalbard.

The freeze season settles down more into straight thermodynamics after freeze-over, though low clouds remain important for net heat loss. I've inquired about getting near-real time cloud synaptic state; for now we can only get at those indirectly (but quantitatively) through RASM-ESRL energy fluxes.
Title: Re: The 2017/2018 freezing season
Post by: Shared Humanity on October 23, 2017, 03:54:07 PM
No one should be surprised that our warm fall and winter is setting up as it has for over a decade. (The new Arctic climate regime) The FDD anomaly only trails 2016.

Will we have low volume at the beginning of next years melt season?

Oh...and with regards to my predictions about this just completed melt season? The next time I record any prediction on this site will be my 1st. While this may be fun for some, it is little more than placing a bet on a roulette wheel. If you want to weed out the fools who don't have a clue, require the person making a prediction include a $1000 bet and watch how the votes drop.
Title: Re: The 2017/2018 freezing season
Post by: Daniel B. on October 23, 2017, 07:52:23 PM
Quote
most probably places the <1 mkm2 event beyond 2020.
The same rubbish every fall, catastrophism after low years, recovery chatter after upticks. What could possibly serve as a scientific basis for a 4+ year weather-ocean-ice forecast? In some ways, 2007 was the most disturbing year to date; neither it nor 2012 were foreseen or foreseeable.

Very few of our registrants seem to take any substantive interest in the 2017/18 freezing season, the topic of this forum. Sharing of ungrounded speculation and personal hunches is very boring. Maybe we should just shut it down and come back in May. Visitation levels don't justify the effort.

SMOS 3.1 thin ice thickness is an interesting way to track the season though. If ice doesn't thicken much during the winter (as expected from Arctic amplification), there's that much less to melt during the melt season. Thinner ice also responds very differently to wind dispersion and export.

The first animation compares newly formed ice from 2012-2017 for the 21st of October; there's quite a bit of variability. The still image shows the same years side by side. The bottom animation computes the six year average for this date and flickers 2017 over it.

Whole Arctic trend-lining is far less informative than regional trend-lining, itself little done on our forums even though wipneus posts the necessary data. 2D maps take regional trend-lining to its end state, the resolution of the data. As there's no physical basis for drawing 'Beaufort' or 'Chukchi' boundaries etc, maps can show what is going on free of nomenclatural bias. To first order, that is latitudinal freeze-up about the cold pole (rather than the north pole).

SMOS in a sense integrates all the heat fluxes between atmosphere, newly forming ice and ocean. Since the weather has been so uneventful for so long, bottom growth prediction for older ice will have fewer problems than in past years. The interest right now is the date of final freeze-over, which is going rather slowly in the Beaufort-Chukchi-ESAS regions and unremarkably above Svalbard.

The freeze season settles down more into straight thermodynamics after freeze-over, though low clouds remain important for net heat loss. I've inquired about getting near-real time cloud synaptic state; for now we can only get at those indirectly (but quantitatively) through RASM-ESRL energy fluxes.

I agree with you first paragraph, as bad news breed negativism, and good news optimism.  The current Arctic sea ice extent is fifth lowest, as stated.  Although the current trend is likely to pass 2009 in the next day or two into sixth lowest, and possibly 2010 soon.  The growth of the sea ice from the September minimum until today is quite average.  The growth thus far this season is 2.6 sq. km., compared to a 10-year average of 2.7, and a longer term average of 2.5, although there is a slight tendency of low minimum years to have greater ice growth.  Not only is <1 mkm2 likely pushed beyond 2020, it is likely pushed mush farther beyond.
Title: Re: The 2017/2018 freezing season
Post by: A-Team on October 23, 2017, 08:51:46 PM
You've confused rapid fall extent onset, which is a bad thing for ice future because it holds the ocean heat in, with volume growth which puts more of a burden on the next melt season but is disfavored by heat-retaining water under a skin of ice.

Which melt season is driven by future weather that you (and everyone else) have not the slightest clue about, a la 2007 and 2012. Watch that 30 year sea ice age video of Tschudi's -- it's all right there.

When will the Bering Strait and Chukchi freeze over this year, relative to 2016? No one has the slightest idea. That date has nothing whatsoever to do with whole-ocean trend mumbo-jumbo.

Oren is on point. (Note attached on-topic data supporting views.)  It's the dog walking on its two hind legs: we applaud not so much that the air cold enough for volume recovery but that is cold and dark enough to have open water freezing in late October. How much the ice will thicken over the winter depends quantitatively on HOW cold the air is, not merely that it is cold (below -1.8ºC).

This is the freeze forum, one of our rare science areas. We have dedicated forums for extent, area and volume trend-trackers. Please delete off-topic, unsupported speculation and move it somewhere appropriate.
Title: Re: The 2017/2018 freezing season
Post by: Neven on October 23, 2017, 10:57:12 PM
This is the freeze forum, one of our rare science areas. We have dedicated forums for extent, area and volume trend-trackers. Please delete off-topic, unsupported speculation and move it somewhere appropriate.

Agreed, never mind the fact that what you say, makes no sense.

I'm planning on becoming more active here in November. I want to be ready for next year's melting season.
Title: Re: The 2017/2018 freezing season
Post by: Pavel on October 24, 2017, 12:12:38 AM
What I've marked from the current freezing:
I don't know what to say more. It's cold and the water freezes - the summary of the freezing season
Title: Re: The 2017/2018 freezing season
Post by: oren on October 24, 2017, 12:43:55 AM
What I've marked from the current freezing:
  • The Garlic Press worked hard and there's a lot of thick ice in the CAA already
  • The Fram export resumes but still low. There could be more MYI in the CAB by the end of the freezing than last year.
I don't know what to say more. It's cold and the water freezes - the summary of the freezing season
Well said Pavel. Last winter the arctic kept moving towards the Atlantic side, which was what kept the Chukchi open for quite a while, the Beaufort mostly free of MYI, and the max volume at a low level (coupled with low FDDs of course). OTOH, this same phenomenon may have stalled this summer's Atlantic melt, as a lot of volume was stuck on this side of the arctic. I suspect the same happened in the CAA, where last year's garlic press brought a lot of ice this summer that insisted on not melting out, despite warm temps and a lot of melt ponds.
A-Team, thanks as usual for the deep-level animations and data.
And SH, thanks for reminding about the FDD anomaly chart, though I prefer the seasonal version (attached) that better tracks the effects of temps on refreeze.
Title: Re: The 2017/2018 freezing season
Post by: Niall Dollard on October 24, 2017, 01:28:18 AM
it is likely pushed mush farther beyond.

Pushed mush? Freudian slip, Daniel ?

Sounds appropriate though  :)
Title: Re: The 2017/2018 freezing season
Post by: Adam Ash on October 24, 2017, 10:25:51 AM
Quote
most probably places the <1 mkm2 event beyond 2020.
... Not only is <1 mkm2 likely pushed beyond 2020, it is likely pushed mush farther beyond.

Respectfully, are we not watching the winding down of a series of bounded but inherently chaotic events.  We have all the things we know (ice states, energy balance etc) plus a goodly swarm of known and unknown unknowns.  I wish Cryosphere was still maintaining the Tale of the Tape which showed us the on-going anomalies in polar ice extent etc. 

That to me presented the wriggles found in any decaying complex system where some seasons were strong and others weak, when it looked hopeless it sometimes rebounded, when it looked staunch sometimes it fell through the bottom.  The recent monthly and even annual wriggles mean little, only the really long term trends give us a hint of what to expect.   <1M sqkm will happen.  And right now nothing humanity is doing will extend the date it does. 
https://www.esrl.noaa.gov/gmd/ccgg/trends/ (https://www.esrl.noaa.gov/gmd/ccgg/trends/)

The PIOMAS volume anomaly chart seems to disguise the somewhat exponential nature of the downward trend because it looks like it annually increments the base used to calculate the anomaly (currently 1979-2016),
http://psc.apl.uw.edu/wordpress/wp-content/uploads/schweiger/ice_volume/BPIOMASIceVolumeAnomalyCurrentV2.1.png

Perhaps the quiet-time of the 2017 freezing season could be usefully spent keeping a weather-eye out for black swans, and watching for impacts of the Artic ice and weather on climate further afield.

Title: Re: The 2017/2018 freezing season
Post by: Iceismylife on October 25, 2017, 08:28:46 PM
<snip>
Which melt season is driven by future weather that you (and everyone else) have not the slightest clue about, a la 2007 and 2012. Watch that 30 year sea ice age video of Tschudi's -- it's all right there.
<snap>
In eastern tradition in the i ching they talk about rain makers. People that influence weather.  This is entirely discounted in the west.  The farmers almanac has a proprietary method for predicting the weather with good results.

My prediction is that the artic basin will be quiet this season. sea ice recovery.  But starting early and trapping heat in
Title: Re: The 2017/2018 freezing season
Post by: StopTheApocalypse on October 26, 2017, 10:15:23 PM
Probably on the wrong side of predictability, but GFS suggests some pretty large heat anomalies next week. This is the 168h.
Title: Re: The 2017/2018 freezing season
Post by: Shared Humanity on October 26, 2017, 10:48:38 PM
Looking at the actual temperature forecast for this day, these warm temps appear to coincide with an arctic storm.
Title: Re: The 2017/2018 freezing season
Post by: Shared Humanity on October 26, 2017, 10:50:14 PM
And here is the cloud and precipitation forecast.
Title: Re: The 2017/2018 freezing season
Post by: meddoc on October 27, 2017, 02:40:40 PM
Looking at the actual temperature forecast for this day, these warm temps appear to coincide with an arctic storm.

Shared Humanity
« on: October 26, 2017, 10:48:38 PM » Insert Quote
Looking at the actual temperature forecast for this day, these warm temps appear to coincide with an arctic storm.


The Polar Vortex hadn't had time to even form, it is already shredded to Pieces.
Title: Re: The 2017/2018 freezing season
Post by: Shared Humanity on October 27, 2017, 04:58:56 PM
Forecast has changed significantly in the last 24 hours. November 2, now 144 hours out is not nearly as warm.

Supports the opinion of many here that 7 day forecasts cannot be trusted.
Title: Re: The 2017/2018 freezing season
Post by: Shared Humanity on October 27, 2017, 05:05:44 PM
The low that was forecast to enter the CAB is now expected to traverse the Bering and Chukchi but it will advect a lot of moisture into the CAB and the pole is very cloudy. Can't be good.
Title: Re: The 2017/2018 freezing season
Post by: Shared Humanity on October 27, 2017, 05:10:33 PM
I'm actually struggling to understand these forecast maps. Both precipitation and cloud cover are supposed to be forecast. It is easy to see the precipitation forecasts but I'll be damned if I can understand cloud cover here. How are you supposed to see % overcast?

Does solid white mean thick cloud cover? If so the Arctic is forecast to be solidly overcast for the entire next week.
Title: Re: The 2017/2018 freezing season
Post by: jdallen on October 28, 2017, 12:28:47 AM
Very few of our registrants seem to take any substantive interest in the 2017/18 freezing season, the topic of this forum. Sharing of ungrounded speculation and personal hunches is very boring. Maybe we should just shut it down and come back in May. Visitation levels don't justify the effort.
Please continue.  I apologize for my lack of participation over the last few weeks - personal events have overtaken me (including surgery and full recovery from thereof).  I hope to be back on the saddle shortly.

I've been catching up on your graphing A-Team, and rolling around in my noggin is a notion of trying to model heat flow via a comparison of sea water temperatures, estimates of sea ice and snow thickness, sea surface temperatures and net atmospheric moisture content.

It is ambitious, but I'm going to start looking on in the developers forum for standards, sources and methods to assemble gridded data.

With that, the next set would be to apply various heat flow equations to each of the layers to come up with a composite heat loss number for each grid cell.  I think an average over time is indicated here.

Overall goal is to have that as a tool we can use which would help understand the refreeze dynamics.  Net heat loss I think is key.
Title: Re: The 2017/2018 freezing season
Post by: StopTheApocalypse on October 28, 2017, 12:38:26 AM
I'm actually struggling to understand these forecast maps. Both precipitation and cloud cover are supposed to be forecast. It is easy to see the precipitation forecasts but I'll be damned if I can understand cloud cover here. How are you supposed to see % overcast?

Does solid white mean thick cloud cover? If so the Arctic is forecast to be solidly overcast for the entire next week.

It's incredibly frustrating that both sea ice and clouds are essentially the same color. A product with off color ice/clouds would be helpful, I think. And yes, a better color scheme with more variation for cloud cover would be useful as well.
Title: Re: The 2017/2018 freezing season
Post by: jdallen on October 28, 2017, 12:42:25 AM
The farmers almanac has a proprietary method for predicting the weather with good results.
*What*?!

Ok, I'll overlook that, but I agree that we will see rapid recovery of SIE and commensurate trapping of enthalpy in the Arctic Ocean.

SIE *will* appear to recover faster against past years and the average *exactly* because as per the last 10 years, there is far more open water to be covered.

I keep seeing this sort of thing cited as recovery.  It isn't.

Here are the *only* things which I think can be accurately described as Arctic "recovery":

1) Net multiple (at least 3, preferably 5) year over year decreases in Arctic Ocean total enthalpy.
2) Net multiple year over year increases in total Arctic sea ice volume.

That's *it*.

Any other metrics are going to be derivative of and affected by other forces in play which are far more volatile.

Title: Re: The 2017/2018 freezing season
Post by: Brigantine on October 28, 2017, 12:52:32 AM
trying to model heat flow

That sounds very interesting.

With all this talk of early ice growth trapping summer heat in the water underneath the ice, I've been wondering what data there is on that... and at what depth the water temperature is most relevant for a seasonal ice outlook.

I know ARGO floats have some capability to operate under sea ice and save up the data until it's safe to transmit... but I've never seen any actual data beyond 65N.
Title: Re: The 2017/2018 freezing season
Post by: jdallen on October 28, 2017, 01:03:26 AM
trying to model heat flow

That sounds very interesting.

With all this talk of early ice growth trapping summer heat in the water underneath the ice, I've been wondering what data there is on that... and at what depth the water temperature is most relevant for a seasonal ice outlook.

I know ARGO floats have some capability to operate under sea ice and save up the data until it's safe to transmit... but I've never seen any actual data beyond 65N.
Almost by definition there will be guess work involved regarding water temperatures, as once the ice is in place we no longer have satellite data.  For data on temperatures at depth, we're much worse off - but that's exactly one of the factors I need for following what I think is a key metric - total arctic ocean enthalpy.  I'm mulling how to source that, and I think it's key to the refreeze as well.
Title: Re: The 2017/2018 freezing season
Post by: Ice Shieldz on October 28, 2017, 02:23:09 AM
The Polar Vortex hadn't had time to even form, it is already shredded to Pieces.

Hi meddoc, what metric or timeframe are you looking at? Our developing PV doesn't seem that unusual to me.
Title: Re: The 2017/2018 freezing season
Post by: Thomas Barlow on October 28, 2017, 04:01:33 PM

""Arctic Sea-Ice is much thinner than we thought""
https://www.youtube.com/watch?time_continue=146&v=L6kndSJiu8c
Title: Re: The 2017/2018 freezing season
Post by: meddoc on October 28, 2017, 05:39:17 PM
The Polar Vortex hadn't had time to even form, it is already shredded to Pieces.

Hi meddoc, what metric or timeframe are you looking at? Our developing PV doesn't seem that unusual to me.

I was looking at surface Temps by the French Meteo Animation. It looked like that to me.
But, now checking nullschool.com it "only" shows it being tossed around.
Title: Re: The 2017/2018 freezing season
Post by: Niall Dollard on October 28, 2017, 07:14:05 PM
I'm actually struggling to understand these forecast maps. Both precipitation and cloud cover are supposed to be forecast. It is easy to see the precipitation forecasts but I'll be damned if I can understand cloud cover here. How are you supposed to see % overcast?


Much better depiction of cloud cover to be had here :

https://weather.us/model-charts/standard/north-pole/total-cloud-coverage/20171102-0000z.html

Can be broken down into low,middle and high cloud also.
Title: Re: The 2017/2018 freezing season
Post by: Shared Humanity on October 28, 2017, 08:26:59 PM
Thanks. Much better except for the choice to use dark gray for 100% cover. Clearly the clouds only cover a portion of the Arctic Ocean.
Title: Re: The 2017/2018 freezing season
Post by: jdallen on October 29, 2017, 07:45:56 AM
Much better depiction of cloud cover to be had here :

https://weather.us/model-charts/standard/north-pole/total-cloud-coverage/20171102-0000z.html

Can be broken down into low,middle and high cloud also.
Incredibly useful!  Thanks!
Title: Re: The 2017/2018 freezing season
Post by: Shared Humanity on October 29, 2017, 03:24:28 PM
Much better depiction of cloud cover to be had here :

https://weather.us/model-charts/standard/north-pole/total-cloud-coverage/20171102-0000z.html

Can be broken down into low,middle and high cloud also.
Incredibly useful!  Thanks!

Is this available on ASIB's chart tab?
Title: Re: The 2017/2018 freezing season
Post by: Neven on October 29, 2017, 03:32:21 PM
Is this available on ASIB's chart tab?

You mean the ASIG? I had a look yesterday evening, as it would be a great addition, but I can't link to the images.
Title: Re: The 2017/2018 freezing season
Post by: Shared Humanity on October 29, 2017, 03:55:00 PM
Yes, meant ASIG. Too bad. Could you set these kinds of resources up as just a link to the site?
Title: Re: The 2017/2018 freezing season
Post by: meddoc on October 29, 2017, 04:02:35 PM
Looks like another very rare Earthquake close to the NP. M 6.0!!!
When the Top of the World moves- You can bet it will move the whole Northern Hemisphere.

Isostatic Rebound kicking in big- time. This, along with the ramping up of Extreme Weather Eevents in spite of a "Rebound Year" is Worrying.

https://watchers.news/2017/10/28/shallow-m6-0-earthquake-hits-north-of-franz-josef-land-arctic-ocean/
Title: Re: The 2017/2018 freezing season
Post by: Neven on October 29, 2017, 05:55:25 PM
Yes, meant ASIG. Too bad. Could you set these kinds of resources up as just a link to the site?

Yes, I can, and I might do that when I update the ASIG next time.
Title: Re: The 2017/2018 freezing season
Post by: Hyperion on October 30, 2017, 08:12:36 AM
trying to model heat flow

That sounds very interesting.

With all this talk of early ice growth trapping summer heat in the water underneath the ice, I've been wondering what data there is on that... and at what depth the water temperature is most relevant for a seasonal ice outlook.

I know ARGO floats have some capability to operate under sea ice and save up the data until it's safe to transmit... but I've never seen any actual data beyond 65N.
Itp 95 hovering around 84nth polewards of svalberd has been showing some regular overturning to below 700m with above the scale temps and salinity rising from deep to replace surface to depth downwelling as the surface cools. This location being well inside the pack, this cannot be good for atlantic side ice formation/survival. Particularly over deep ocean as tis. As of day 304:
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fwww.whoi.edu%2Fitp%2Fimages%2Fitp95dat3.jpg&hash=6ebb094c548a14820c3f9f50dcc04a22)
They have some new buoys itps 100,101,108 out on the central beaufort. They appear to be showing the halocline stabilising there, after a shaky period before it crusted over, not much salinity differential compared to a decade back.
Title: Re: The 2017/2018 freezing season
Post by: meddoc on October 30, 2017, 11:31:44 AM
Paul Beckwith reflecting on a Study, that basically said: FYI is 13- 25% overestimated in Thickness, because of Sensor Microwave Penetration affected by Sea Salt deposited from battering Ocean Waves.

https://www.youtube.com/watch?v=L6kndSJiu8c
Title: Re: The 2017/2018 freezing season
Post by: RoxTheGeologist on October 30, 2017, 05:56:00 PM

There is little isostatic rebound close to the north pole. Sea ice is compensated as it floats. Mass loss of the Greenland ice sheet may be causing some variations, but, at an educated guess, asthenospheric flow changes don't change rapidly enough to notice on a yearly scale. Perhaps over the course of a century you might notice a change. That earthquake is like to be a result of the slow spreading of the Gakkel MOR:

http://www.sciencedirect.com/science/article/pii/S1873965214000693
Title: Re: The 2017/2018 freezing season
Post by: FishOutofWater on October 30, 2017, 07:04:27 PM
The 3 earthquakes N of FJL, M5.7, 5.7 and 6.0 were all normal faulting earthquakes. They may be associated with a submarine volcanic center associated with the very slowly extending Gakkel ridge.

Thanks Rox, for the journal link. We need to stick to the science.
Title: Re: The 2017/2018 freezing season
Post by: FishOutofWater on October 30, 2017, 07:14:52 PM
The stratospheric polar vortex is forecast by the GFS to become very elongated over the next week to 10 days. This pattern will bring warm air to the East Siberian seas and cold air to western Canada. Repeated cold air outbreaks are likely to hit the central U.S. in this pattern.

It's a variation of the warm Arctic cold continents pattern.
Title: Re: The 2017/2018 freezing season
Post by: echoughton on October 30, 2017, 08:05:11 PM
wish there was a "Like" button...and others like on FB..I keep looking for it and it never appears. :o
Title: Re: The 2017/2018 freezing season
Post by: Pavel on October 30, 2017, 08:28:56 PM
It's gonna be very cold in the CAA that it should have significant ice volume + the Garlic Press. But on the other hand the Pacific side will still struggle to freeze up. Also the Low Pressure system in the Barents sea boosts the Fram export.
Title: Re: The 2017/2018 freezing season
Post by: jdallen on October 31, 2017, 07:07:56 AM
trying to model heat flow

That sounds very interesting.

With all this talk of early ice growth trapping summer heat in the water underneath the ice, I've been wondering what data there is on that... and at what depth the water temperature is most relevant for a seasonal ice outlook.

I know ARGO floats have some capability to operate under sea ice and save up the data until it's safe to transmit... but I've never seen any actual data beyond 65N.
Itp 95 hovering around 84nth polewards of svalberd has been showing some regular overturning to below 700m with above the scale temps and salinity rising from deep to replace surface to depth downwelling as the surface cools. This location being well inside the pack, this cannot be good for atlantic side ice formation/survival. Particularly over deep ocean as tis. As of day 304:
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fwww.whoi.edu%2Fitp%2Fimages%2Fitp95dat3.jpg&hash=6ebb094c548a14820c3f9f50dcc04a22)
They have some new buoys itps 100,101,108 out on the central beaufort. They appear to be showing the halocline stabilising there, after a shaky period before it crusted over, not much salinity differential compared to a decade back.
It is on the Atlantic side that I think most desperately needs instrumentation, to track exactly the kind of overturning and changes in the water column you are mentioning.  While the Bering and increased captured insolation are important to what we see playing out, I think input from warm more saline Atlantic water is really what will tip the balance in the Arctic's heat budget.
Title: Re: The 2017/2018 freezing season
Post by: Niall Dollard on October 31, 2017, 11:56:53 AM
But on the other hand the Pacific side will still struggle to freeze up.

Seems to be what the NWS Anchorage are saying too, in their monthly outlook (http://tgftp.nws.noaa.gov/data/raw/fz/fzak30.pafc.ico.afc.txt).
"FREEZE-UP TIMING IS EXPECTED TO BE SIMILAR TO LAST YEAR ESPECIALLY IN THE CHUKCHI SEA AND NORTHERN BERING SEA DUE TO THE CONTINUED WARM SEA SURFACE
TEMPERATURES."

Although they conclude with "THE BERING SEA MAY SEE SLIGHTLY GREATER SEA ICE EXTENT
THAN IN RECENT YEARS."
 
(Note: the capital emphasis is just as copied from their site and nothing especial intended by it !) 
Title: Re: The 2017/2018 freezing season
Post by: Daniel B. on October 31, 2017, 03:16:46 PM
The 3 earthquakes N of FJL, M5.7, 5.7 and 6.0 were all normal faulting earthquakes. They may be associated with a submarine volcanic center associated with the very slowly extending Gakkel ridge.

Thanks Rox, for the journal link. We need to stick to the science.

You may like this link also, detailing past affects of volcanic activity on Arctic ice.

https://www.nature.com/articles/s41467-017-01273-1
Title: Re: The 2017/2018 freezing season
Post by: FishOutofWater on October 31, 2017, 04:27:11 PM
The Gakkel ridge, a very slow spreading center, is effectively decoupled from the effects of glacial unloading. Greenland, Iceland and Alaska, however, have coupled volcanism and glacial melting.
Yes, this is an interesting article;

Our data indicate that abrupt ice melting events coincide with volcanogenic aerosol emissions recorded in Greenland ice cores. We suggest that enhanced ice sheet runoff is primarily associated with albedo effects due to deposition of ash sourced from high-latitude volcanic eruptions. Climate and snowpack mass-balance simulations show evidence for enhanced ice sheet runoff under volcanically forced conditions despite atmospheric cooling.

Note that tropical volcanism is more effective at atmospheric cooling than polar and subpolar volcanism. Note also, while Europe was cool in the '60s and '70s because of sulfate pollution, black carbon pollution was melting European glaciers. Increasing fire in northern reaches is also adding to glacial melting.
Title: Re: The 2017/2018 freezing season
Post by: numerobis on October 31, 2017, 10:49:12 PM
Bit of a storm shaking things up in Hudson Bay and Baffin (after devastating parts of Maine and the Ottawa region). I assume it’ll delay the freeze-up a bit more. We haven’t seen any sea ice yet, and this storm is a few degrees above the temperature it’s been lately.


Being in tropical storm force winds for 24 hours at a time is a new experience for me. It’s a bit unpleasant. I can’t imagine waiting it out in a hide tent (there’s not enough snow for an igloo yet).
Title: Re: The 2017/2018 freezing season
Post by: Martin Gisser on October 31, 2017, 11:16:08 PM
Being in tropical storm force winds for 24 hours at a time is a new experience for me. It’s a bit unpleasant. I can’t imagine waiting it out in a hide tent (there’s not enough snow for an igloo yet).
Depends on the construction. The Plains Indian tipi is quite storm resistant. Have experienced that: All other tents blown away, the tipi still standing (except one broken pole). Dunno if they have it up there. The Sami in northern Scandinavia and some northern Siberian people also use tents similar to the tipi.
https://en.wikipedia.org/wiki/Tipi
https://en.wikipedia.org/wiki/Lavvu
https://en.wikipedia.org/wiki/Chum_(tent)
Title: Re: The 2017/2018 freezing season
Post by: Hyperion on November 01, 2017, 05:32:34 AM
Quote
It is on the Atlantic side that I think most desperately needs instrumentation, to track exactly the kind of overturning and changes in the water column you are mentioning.  While the Bering and increased captured insolation are important to what we see playing out, I think input from warm more saline Atlantic water is really what will tip the balance in the Arctic's heat budget.

Actually I may have spoke too soon. Itps 100@80-146, 101@81-127, 108@80-137 are now all showing a flat temp and salinity profile surface to 500m ish. The fact that only 25m of a few psu less salinity is lidding this area has been concerning me. The brine rejected by  a mtr of ice freeze could be enough to flatten the halocline. And then any surface cooling will overturn to depth. May improve outgoing winter heat flux. But seems likely this would jump us to year round ice free in a couple of years. Itp 95: 83.9024° N, 24.4681° E also below at day 305 looking halodeclined
Title: Re: The 2017/2018 freezing season
Post by: Pavel on November 01, 2017, 09:16:01 AM
Interesting GFS forecast for 10 November. The coldness could be everywhere except the inner basin
Title: Re: The 2017/2018 freezing season
Post by: Niall Dollard on November 01, 2017, 01:47:49 PM
NSIDC is showing new ice in James Bay and Eastern Hudson. Likely very thin and fragile at the moment.

Strangely I couldn't find any updates on the normally excellent Canadian Ice Service. Only concentrating on the northern Hudson.  :o
Title: Re: The 2017/2018 freezing season
Post by: Shared Humanity on November 01, 2017, 03:35:52 PM
Interesting GFS forecast for 10 November. The coldness could be everywhere except the inner basin

It is very nice if legends are included when images are posted.
Title: Re: The 2017/2018 freezing season
Post by: aperson on November 01, 2017, 08:04:20 PM
Interesting GFS forecast for 10 November. The coldness could be everywhere except the inner basin

It is very nice if legends are included when images are posted.

Additionally, we should abstain from posting model forecasts past tau=120h on them. The GFS is a total tossup after this period, ECMWF is slightly better. At 5d+ intervals we should only be looking for very basic synoptic trends from the model runs.
Title: Re: The 2017/2018 freezing season
Post by: Dharma Rupa on November 02, 2017, 01:38:12 AM
Interesting GFS forecast for 10 November. The coldness could be everywhere except the inner basin

It is very nice if legends are included when images are posted.

Additionally, we should abstain from posting model forecasts past tau=120h on them. The GFS is a total tossup after this period, ECMWF is slightly better. At 5d+ intervals we should only be looking for very basic synoptic trends from the model runs.

Not really clear to me why predictions are being posted at all -- other than perhaps seasonal ones.
Title: Re: The 2017/2018 freezing season
Post by: Shared Humanity on November 02, 2017, 02:53:52 AM
Interesting GFS forecast for 10 November. The coldness could be everywhere except the inner basin

It is very nice if legends are included when images are posted.

Additionally, we should abstain from posting model forecasts past tau=120h on them. The GFS is a total tossup after this period, ECMWF is slightly better. At 5d+ intervals we should only be looking for very basic synoptic trends from the model runs.

Not really clear to me why predictions are being posted at all -- other than perhaps seasonal ones.

This thread tracks the freeze season. How is this any different than tracking the melt season where all manner of predictions are reviewed and discussed? It is entirely appropriate to post any items related to the current freeze season. And somebody who is posting their 12th comment has decided to set the rules for what is or is not appropriate??
Title: Re: The 2017/2018 freezing season
Post by: meddoc on November 02, 2017, 07:43:06 AM
This is also what nullschool Forecasts in 4 days- not uncommon Configuration since 2014 January
The Polar Vortex is virtually split into two Cores above the Last Remaining Bastions of Ice:
Greenland & Siberian Permafrost
Title: Re: The 2017/2018 freezing season
Post by: Ice Shieldz on November 02, 2017, 04:45:04 PM
That kind of stratospheric PV pattern (5-days out) enables the kind of the polar jet moisture/heat intrusion over Chukch & Bering sea region like we've seen during fall-winter 2016-2017. For what it's worth the stratospheric PV is forecasted to tighten up more after 10 days.  see:  http://www.aer.com/science-research/climate-weather/arctic-oscillation (http://www.aer.com/science-research/climate-weather/arctic-oscillation)
Title: Re: The 2017/2018 freezing season
Post by: Alexander555 on November 04, 2017, 12:35:13 PM
I have been reading the 2017 melt season for a couple months. That was easy to follow, because i just had to read the numbers. But the freezing season is harder to get. What is the problem ?  Is the arctic not doing what it should be doing at this time. The melting season stoped somewhere in september, if i'm correct. And now we are in november. Is it not adding extra ice every day ?
Title: Re: The 2017/2018 freezing season
Post by: gerontocrat on November 04, 2017, 01:02:40 PM
I have been reading the 2017 melt season for a couple months. That was easy to follow, because i just had to read the numbers. But the freezing season is harder to get. What is the problem ?  Is the arctic not doing what it should be doing at this time. The melting season stoped somewhere in september, if i'm correct. And now we are in november. Is it not adding extra ice every day ?

For numbers on the freezing season goto "2017 sea ice area and extent data"
Title: Re: The 2017/2018 freezing season
Post by: Sterks on November 04, 2017, 01:26:18 PM
I have been reading the 2017 melt season for a couple months. That was easy to follow, because i just had to read the numbers. But the freezing season is harder to get. What is the problem ?  Is the arctic not doing what it should be doing at this time. The melting season stoped somewhere in september, if i'm correct. And now we are in november. Is it not adding extra ice every day ?
Just boring. No cataclysm in sight
Title: Re: The 2017/2018 freezing season
Post by: dnem on November 04, 2017, 03:00:27 PM
Certainly no expert Alexander, but there is a lot more to the melting season than just "the numbers." For example, always a lot of debate about extent vs area vs volume, as well as questions about regional happenings.  As for this freezing season, yes, the arctic is almost entirely below freezing now and ice is being added most everywhere.  But how much? Where? Has it been warmer so far than other freeze seasons? (yes, warmer than most; no, not as warm as last year). How about the issue of how an early freezeup might "seal in" heat that might otherwise be lost to space.  There is tons to learn here across the many threads.
Title: Re: The 2017/2018 freezing season
Post by: Shared Humanity on November 04, 2017, 03:49:47 PM
I have been reading the 2017 melt season for a couple months. That was easy to follow, because i just had to read the numbers. But the freezing season is harder to get. What is the problem ?  Is the arctic not doing what it should be doing at this time. The melting season stoped somewhere in september, if i'm correct. And now we are in november. Is it not adding extra ice every day ?

This current freeze season is behaving very similar to recent freeze seasons with much warmer temperatures than normal and much lower SIE and SIA than normal at this point in the freeze season. No catastrophe in sight, just not the kind of polar winters that existed 3 decades ago. If you have been following the melt season as close as you have suggested, the exact same charts and data will tell you what I have just said. Follow....

Volume
SIA
SIE
Temperatures and temp anomalies
etc.

To really develop an understanding, follow the comments of expert posters here who know and understand far more than I do.

How do you tell the experts from the band of trolls who like to misdirect? I always look at the comment totals. We have people who have provided keen insights for over 4 years and have posted more than 4000 comments. You can also distinguish the valuable from the useless by whether the commenter attaches charts, graphs, data and links to research to support their comments. The experts will also often qualify their statements to allow for some uncertainty regarding their viewpoints if warranted. Trolls will categorically insist they are correct, impugn the integrity of others on this site while providing nothing to support their views. It can become tedious to wade through the trash to get real information. The strategy I use has worked for me. I will read all comments posted, reserving judgement about the value of the contributor. When it becomes clear the person is a troll, I set them on ignore so I don't have to read their trash anymore.
Title: Re: The 2017/2018 freezing season
Post by: Shared Humanity on November 04, 2017, 03:54:14 PM
Oh...by the way...this is quite simply the best, most comprehensive climate change site available IMHO.
Title: Re: The 2017/2018 freezing season
Post by: numerobis on November 04, 2017, 07:31:51 PM
No cataclysm, but no ice in Iqaluit yet, or even as far up as Qik. Unless some ice starts to form this week, it'll be slower than last year in this specific locality.

I'm seeing some deniers crow about how much faster the freeze-up is going this year than last year. Yawn.
Title: Re: The 2017/2018 freezing season
Post by: magnamentis on November 04, 2017, 08:49:27 PM
No cataclysm, but no ice in Iqaluit yet, or even as far up as Qik. Unless some ice starts to form this week, it'll be slower than last year in this specific locality.

I'm seeing some deniers crow about how much faster the freeze-up is going this year than last year. Yawn.

yawn indeed but their pleasure will be short lived IMO

next stall or at least reduction in speed in sight like recently and another 2 or 3 of those of which this is the 2nd huge storm at high temps on the pacific side without specially low temps on the atlantic side, and we shall loose one rank after another until they have to look for new illusions to contaminate the WWW with :D  ;)

one should take from them all their money and give them a 1$ and 2$ next year to teach them that more does not always mean a lot or enough, not even double ;)
Title: Re: The 2017/2018 freezing season
Post by: meddoc on November 05, 2017, 12:19:58 PM

Just boring. No cataclysm in sight


Yawn. Just ask around about Trump threatening with Nuclear War (Winter), purely coincidentally.
Title: Re: The 2017/2018 freezing season
Post by: numerobis on November 06, 2017, 01:07:12 AM
yawn indeed but their pleasure will be short lived IMO

Will it? It would be shocking if this freezing season were even worse than last year's.
Title: Re: The 2017/2018 freezing season
Post by: Brigantine on November 06, 2017, 01:34:16 AM
Itp 95 hovering around 84nth polewards of svalberd has been showing some regular overturning to below 700m with above the scale temps and salinity rising from deep to replace surface to depth downwelling as the surface cools.
Looking at the "Plot of ITP T & S Contours" vs the contents of "itp95last.dat" for the 3rd and 4th of November...

I really have to suspect that there is no such "overturning to below 700m", and that it only looks like that on the contour plot because of how they fill in missing data.

The 3rd of November had a massive cuision of very cold very fresh water from 26m to 100m, the 4th of November had no data readings shallower than 529m depth... but the contour plot for day 309 (Nov 4th) shows the top 100m as being suddenly warm and salty. There was no actual evidence to suggest a dramatic change.
Title: Re: The 2017/2018 freezing season
Post by: Cid_Yama on November 06, 2017, 01:45:12 AM
Another day or two, 2017 will be second lowest for the date behind 2016.  It has just now caught 2012.  It's going to be another one of THOSE winters in the Arctic.

 https://seaice.uni-bremen.de/data/amsr2/today/extent_n_running_mean_amsr2_previous.png

And Wipneus has just informed us that Fram export has just started up again.
Title: Re: The 2017/2018 freezing season
Post by: gerontocrat on November 06, 2017, 02:41:07 PM
Some Atlantic weather for the weekend?
Title: Re: The 2017/2018 freezing season
Post by: Shared Humanity on November 06, 2017, 03:01:31 PM
yawn indeed but their pleasure will be short lived IMO

Will it? It would be shocking if this freezing season were even worse than last year's.

2016 was unprecedented. 2017 now looks like it is trying to break away from the pack, not only with a slow refreeze but with FDD anomalies as well. The question in my mind, if this continues, is whether we are seeing a shift in winter climate. I have found winters to be as exciting as summers. I just wish there were more experts commenting during the freeze season to explain what I am seeing.
Title: Re: The 2017/2018 freezing season
Post by: gerontocrat on November 07, 2017, 03:11:45 PM
The post by Numerobis above shows the FDD anomaly, which though high is significantly below 2016. The first image below shows 2017 and 2016 Daily Mean Temperatures North of 80 degree North, so far somewhat colder this year though still well above average.

The second image shows temperature anomalies forecast for the next few days, which indicate the continuation of high positive anomalies on the extreme Atlantic and Pacific sides of the Arctic, as has been the case for some time.

Will this pattern persist and what will be the effect on the where and when of freezing in extent and volume?
Title: Re: The 2017/2018 freezing season
Post by: Pavel on November 07, 2017, 04:50:07 PM
The point is that there will definetly be some weak ice in the Pacific side of CAB by the end of freezing. This ice may dissapear quickly in any weather conditions as it happened this July\August. But Spring and June are very important to upload a new canonball if the conditions will be favourable to early melting. Last season it was cold\snowy\cloudy
Title: Re: The 2017/2018 freezing season
Post by: Niall Dollard on November 07, 2017, 05:10:53 PM
Some Atlantic weather for the weekend?

I don't know where you got that chart from Gerontocrat but the pressure centre labelling is all mixed up. Look at the three centres I've circled in bright green labelled "H".

The surface wind goes around the centres in an anticlockwise fashion so in the NH, they should be labelled "L".   :)
Title: Re: The 2017/2018 freezing season
Post by: gerontocrat on November 07, 2017, 05:16:19 PM

I don't know where you got that chart from Gerontocrat but the pressure centre labelling is all mixed up. Look at the three centres I've circled in bright green labelled "H".

The surface wind goes around the centres in an anticlockwise fashion so in the NH, they should be labelled "L".   :)
Weather-forecast.com. It is a big operation.
They have always screwed up like that. I don't know why. I used to compare their image with other places and they looked all ok except for that basic dumbness. Perhaps someone ought to ask them.
Title: Re: The 2017/2018 freezing season
Post by: Niall Dollard on November 07, 2017, 05:33:32 PM
No worries.

I like to use the weather.us charts for the northpole view. I see the Euro model is going for a large HP centre (>1050 hPa) just to the Russian side of the Arctic Basin by this time next week.

Title: Re: The 2017/2018 freezing season
Post by: Shared Humanity on November 07, 2017, 05:57:16 PM
1 week out forecast....blehhhhh
Title: Re: The 2017/2018 freezing season
Post by: numerobis on November 07, 2017, 08:09:21 PM
Won’t be long for the freeze-up in Iqaluit: at noon, I looked up and saw the brown mud flats of low tide; at 1 pm they were bright white in Koojesse Inlet, but still brown further out. I hear, from someone who just flew in, that was the scene all the way down the bay.

Also our first day with sundogs.

Also, out last tanker of the season just arrived to give us our final dose of fossil fuels until July.
Title: Re: The 2017/2018 freezing season
Post by: oren on November 07, 2017, 09:43:27 PM
2016 was unprecedented. 2017 now looks like it is trying to break away from the pack, not only with a slow refreeze but with FDD anomalies as well. The question in my mind, if this continues, is whether we are seeing a shift in winter climate. I have found winters to be as exciting as summers. I just wish there were more experts commenting during the freeze season to explain what I am seeing.
I don't post much on the freezing thread atm as I can't think of much to contribute. What you wrote represents my thinking as well, and I think the jury is still out on whether it's a step-changed winter climate or just random variations on a slow trend.
I just want to point out that the seasonal FDD chart is much more appropriate to this thread than the yearly one.
Title: Re: The 2017/2018 freezing season
Post by: Shared Humanity on November 07, 2017, 09:47:05 PM

I just want to point out that the seasonal FDD chart is much more appropriate to this thread than the yearly one.

You mentioned this once before and, of course, you are correct. I'll try to remember to reference this one in the future.
Title: Re: The 2017/2018 freezing season
Post by: Brigantine on November 08, 2017, 12:02:42 AM
Won’t be long for the freeze-up in Iqaluit

The CIS map for Davis Strait went crazy today. Ice edge has advanced 2 or 300 miles in 2 days. The traces of old ice have been left so far behind they're not even on the charts any more. (Moving at 24 miles/day).

AFAICT south of the narrows (Cape Dyer) it's just a dusting of snow that would melt if the wind changed (the water temps were still 0.8K+ above freezing until just now), but it's only going to keep snowing.

James Bay has the same thing now. New ice on the western margin (and a trace of it all the way around), and more snow on the way. This one is more surprising though as the water is still 2.5C+... (according to nullschool anyway).

Title: Re: The 2017/2018 freezing season
Post by: jdallen on November 08, 2017, 02:58:41 AM
The post by Numerobis above shows the FDD anomaly, which though high is significantly below 2016. The first image below shows 2017 and 2016 Daily Mean Temperatures North of 80 degree North, so far somewhat colder this year though still well above average.

The second image shows temperature anomalies forecast for the next few days, which indicate the continuation of high positive anomalies on the extreme Atlantic and Pacific sides of the Arctic, as has been the case for some time.

Will this pattern persist and what will be the effect on the where and when of freezing in extent and volume?
I think the pattern will persist as long as we have so much open water in the Beaufort and Chukchi.  They're a powerful heat engine right now dumping energy directly into the Arctic.

The higher FDD's are a relief, but we're still below pretty much everything but 2016-2017.  We have an additional wildcard I'm going to be keen about - snowfall.

All of that open water combined with intrusions of moisture on the Pacific side are bound to increase the snowcover we have over the re-frozen ice.  This is translating into much more snowfall, and each additional inch of snow conservatively has 5+ times the insulative value of ice.  I will be interested in snow depth anomalies as much or more than I'll be interested in FDD's. 

Early deep snowfall has the potential to seriously impede late season thickening of the pack.

Aggregate depths in the past came later in the season and were typically below 40CM:

https://www.researchgate.net/publication/241392751_Snow_Depth_on_Arctic_Sea_Ice


Title: Re: The 2017/2018 freezing season
Post by: numerobis on November 08, 2017, 02:39:47 PM
Brigantine: maybe I’ll go take a picture today. Pretty sure it’s ice, not snow.

The tide is very big here and throughout Baffin. At low tide, a thin sheet of water seeps out; you can walk on the mud in hiking boots, but sneakers will get soaked. That sheet of water is what’s freezing first on the shore.

When the tide comes back in, thin ice stays stuck to the sea floor, with sea water above it (which is beautiful!). As it thickens, eventually it’s big enough to tear itself off.
Title: Re: The 2017/2018 freezing season
Post by: Hyperion on November 08, 2017, 08:08:59 PM
Itp 95 hovering around 84nth polewards of svalberd has been showing some regular overturning to below 700m with above the scale temps and salinity rising from deep to replace surface to depth downwelling as the surface cools.
Looking at the "Plot of ITP T & S Contours" vs the contents of "itp95last.dat" for the 3rd and 4th of November...

I really have to suspect that there is no such "overturning to below 700m", and that it only looks like that on the contour plot because of how they fill in missing data.

The 3rd of November had a massive cuision of very cold very fresh water from 26m to 100m, the 4th of November had no data readings shallower than 529m depth... but the contour plot for day 309 (Nov 4th) shows the top 100m as being suddenly warm and salty. There was no actual evidence to suggest a dramatic change.
I'm doubtful that much of this can be attributed to misgraphing of missing data. Many of these stripes are five to ten days wide. And show on disolved oxygen and up-down composit plots for temp salinity and do also. With two sampling descents per day that would be 10-20 missing logging runs in a row and half the last few months being publicly misrepresented.
Title: Re: The 2017/2018 freezing season
Post by: Brigantine on November 09, 2017, 12:51:23 AM
I'm doubtful that much of this can be attributed to misgraphing of missing data.
Ok. Let's dive deeper.

Composite Plot of ITP T & S Profiles: In the top 40 meters, there is exactly one profile showing temperatures above -1.5C. Though the 34 PSU contour does reach up to only 20m depth.

Stripe 1: Days 261-268.
From the engineering data plot, the minimum pressure recorded during this period? Off the charts. Not a single profile during this period reached shallow depths. Motor current was also consistently high, which if I know anything about motors means it got stuck. (more than normal)

Stripe 2 & 3: Days 273-274 & 279.
Again, no profiles reaching shallow water. No obvious signs as to why though.

Stripe 4: Days 283-290.
This is a strange one, on the contour plot the first half of the stripe shows scorching temps down to 35m, then from 60m to 600m, but with normal temps around 35-40m and again right at the bottom (760m). The second half is just scorching from surface to depth.

On the engineering data, the battery voltage has now permanently transitioned to an abnormally low state. The first half of the stripe shows two profiles reaching up to 38m depth, but no better; the second half shows no shallow profiles at all.

Odd Feature at Day 293 - Warm surface feature above 35-40m. Engineering data shows a single profile reaching up to 39m depth, with a small spike in motor current. A similar but weaker surface feature occurs at Day 298, with a profile reaching up to 8m depth and another spike in motor current.

Stripe 5: Days 301-304. Zero shallow profiles, and a larger spike in motor current.

Note that in every gap between these stripes, i.e. everywhere the contour plot shows a fresh & cold surface layer, there are profiles recording pressures right up to 8m depth.

It would have been more conclusive info if the minimum pressure plot had had a wider range on the depth scale, but I'm quite comfortable concluding that the halocline *isn't* suddenly disappearing and then reappearing again.

I must say I'm no longer sure it's only a problem of *missing* data. I wonder if there might also be a factor of high temperature readings occurring when the profiler gets stuck and the motor draws a very high current for a short time - which happens to occur right at the end of the particular profile's range i.e. the one data point most likely to be extrapolated.

I still trust data from individual profiles, and the composite plot of profiles, but I just can't take stripes on the contour plot at face value.
Title: Re: The 2017/2018 freezing season
Post by: Hyperion on November 09, 2017, 02:23:56 PM
Durn!
Ok. Thats a pretty good case for some serious issues with the cable crawler data aquisition unit. I would of thought there would be some pressure sensor cross referencing automated to validate where it thinks its at on the cable, or at least some manual checks. Disapointing that a buoy launched just six months ago is looking so dodgy after a development of almost 100 mostly reliable predecessors.
I had been working on the hypothesis that this recent behaviour was probably due to eddy and vortex mixing from the 14c temp incoming water that is surfacing still west of svalberd doing a right turn and interacting with bottom topography and wave and current effects. Now it seems we have no direct data thats reliable on the Atlantic front at all. Probably growing kelp on its upper cable or some such.
The new ITPS in the north beaufort have also been giving us inconstant contour plots. The past two weekends have given the t&S flat readings surface to depth on all three I pointed out before. Until someone seems to get to work on monday and "Fix" the issue. Happened again today infact. The composit plots look more consistant and are perhaps worth a sqiz for comparison with early plots from 10years ago. ITPS 3,5,6:
(https://www.whoi.edu/cms/images/itp3dat3f_80921.jpg)
(https://www.whoi.edu/cms/images/itp5dat2f_81106.jpg)
(https://www.whoi.edu/cms/images/itp6dat2f_105951.jpg)

Admittedly these are a much longer series, covering up to 3yrs from 2005in the same area as 100,101,108 are now charting, so there is somr data mixed in with open water and shallows. But they see to contrast with ten years later by having a less contiguous pacific warm layer just over 30psu at 50 to 60m depth and temps -1.5 to 0.5. And surface salinities as low as 22psu with generally 5-6psu differential between these depths.
Now we appear to be seeing a more consistant temperature peak at about 40m and only 1-2psu differential with surface.
The big thermal store is in the atlantic layer starting about 200m. But with the anticlockwise low pressure dominated circulation patterns we are increasingly seeing. This is like a spin cycle with fresh riverine influxes not replenishing the halo but expelled by coriolis out bering and CAA, greenland coasts. Big negative sstas in the nth pac and greenland  area presently look like this to me. New north beau buoys As  attached:
Title: Re: The 2017/2018 freezing season
Post by: 2phil4u on November 09, 2017, 02:55:33 PM
If a Low Minimum in average produce higher min next year, The onlY Option ist, thathat ICE is warming, ICE helps Not to lose energy, ICE triggerrd Indikation ist bigger Thema less albedo in Summer.
Smartphone writing ist awful.

Ich




Title: Re: The 2017/2018 freezing season
Post by: Daniel B. on November 09, 2017, 03:59:18 PM
If a Low Minimum in average produce higher min next year, The onlY Option ist, thathat ICE is warming, ICE helps Not to lose energy, ICE triggerrd Indikation ist bigger Thema less albedo in Summer.
Smartphone writing ist awful.

Ich

Yes, smartphone writing is indeed awful.  But I was able to understand you.  I agree that the decreased ice cover results in greater heat loss, temporarily cooling the water.  This will result in a greater ice minimum the following year.  However, this may just be a temporary blip in the long-term decline.
Title: Re: The 2017/2018 freezing season
Post by: Brigantine on November 09, 2017, 09:13:14 PM
But with the anticlockwise low pressure dominated circulation patterns we are increasingly seeing. This is like a spin cycle with fresh riverine influxes not replenishing the halo but expelled by coriolis out bering and CAA, greenland coasts. Big negative sstas in the nth pac and greenland  area presently look like this to me.

Some interesting ideas there that I'll look at more when I have time. The overall freshwater budget of the arctic is definitely of interest.

Regarding the cold blob in the North Pacific, I was of the impression that it came from the direction of Japan, and was related to ENSO. Though what you say makes some sense as I remember a strip of cold anomalies last winter right down the eastern coast of Kamchatka into Okhotsk, and that's exactly what you would expect to see from a super fresh current.
Title: Re: The 2017/2018 freezing season
Post by: Brigantine on November 10, 2017, 11:21:24 PM
Your stripes... What happened? It seems the contour plots have had a little update!

They now show a more plausible story of active deep water formation.
Title: Re: The 2017/2018 freezing season
Post by: Hyperion on November 11, 2017, 07:15:11 PM
Your stripes... What happened? It seems the contour plots have had a little update!

They now show a more plausible story of active deep water formation.
Not sure which you alluding to. 95 still stripy. Not implausibility that pulses of salty water are sliding in under the icepack when basin wide seals do pressure drops. Get cooled to freezing point near surface and sink, and under rising pressure central basin surface waters washing out. Unless we go "Naah, must all just be mechanical!". The co-located imb-crrel-dartmouth.org is potentially able to shed some light if you can strip search it's thermistor string data. Water temp with ice in proximity is a proxy for salinity.

100,101,108. Are continuing to suffer from the case of the here today and gone tomorrow leading edge stripe syndrome.
LOLz, Perhaps Trump has invoked the patriot act and declared clear publication of real world Arctic data to be an act of terrorism by threats to future US oil revenues or military plans. If anyone wants to talk to Woods for any explanation they can give it be great.
Title: Re: The 2017/2018 freezing season
Post by: Hyperion on November 11, 2017, 07:29:20 PM
Amusing language hack by this smart assumption phone there. Basin wide sea level pressure drops. Not basin wide seals do pressure drops. Though I guess the effects could be similar.
It just added umption to my previous sentence I notice also. I am saddened by the censorship of the potentially slightly disturbing by big brother.
Title: Re: The 2017/2018 freezing season
Post by: Hyperion on November 12, 2017, 04:39:14 AM
See. Here we go again. Six hours ago the contours were smooth.
Now it's back to mixed to 500m again.

And reading eg. itp100:
Last profile (number 109) on 2017/11/12 2 UTC
Last profile temperature: minimum = -1.5105, maximum = 0.85202 °C
Last profile salinity: minimum = 29.8848, maximum = 34.8585
Title: Re: The 2017/2018 freezing season
Post by: Neven on November 12, 2017, 10:40:11 AM
If things get too specific, maybe take it to the Buoys thread (https://forum.arctic-sea-ice.net/index.php/topic,327.1800.html)?
Title: Re: The 2017/2018 freezing season
Post by: meddoc on November 12, 2017, 09:10:58 PM
Anyone knows about Hycom Forecasts?
Hasn't been updated since 24th October.
Title: Re: The 2017/2018 freezing season
Post by: numerobis on November 13, 2017, 01:54:30 AM
If a Low Minimum in average produce higher min next year, The onlY Option ist, thathat ICE is warming, ICE helps Not to lose energy, ICE triggerrd Indikation ist bigger Thema less albedo in Summer.
Smartphone writing ist awful.

Ich

Add the 'english' language and the smartphone will autocorrect you to english rather than german.

(Or keep trying, and eventually the smartphone will be bilingual.)
Title: Re: The 2017/2018 freezing season
Post by: Ice Shieldz on November 13, 2017, 07:27:06 AM
2017 Nov 1st to 13th mean 2m air temperature anomalies.  Looks like more WACC-yness. Although this year 80-90 north is holding closer to average.
Title: Re: The 2017/2018 freezing season
Post by: Pavel on November 13, 2017, 08:50:41 AM
Anyone knows about Hycom Forecasts?
Hasn't been updated since 24th October.
It has now a Global version including Antarctica https://www7320.nrlssc.navy.mil/GLBhycomcice1-12/POLAR.html
Title: Re: The 2017/2018 freezing season
Post by: 2phil4u on November 13, 2017, 12:45:19 PM
I like to write on a normal  keyboard, because i know how to write with 10 fingers.
The  smart phone was a cheap replacement and it just suck,the technic is superbad, so i often missclick and  so  on.
What i wanted to illustrate is the fact, that after a summer with more open water, the next minimum tends to be higher.
With this logic it seems like the winter overcompensate and if it is not the case, that say the upper  lawyer i s cooler, but in depth its warmer,  what i dont think is the case, this means, that the arctic has a tremendous negative feedback and so discussions about multiyear ice and quality are just nonsens, just because no ice mans more cooling then the additional warming in summer.
And so  maybe even more true for the N80-90 region, the potential cooling effect of open water is huge,while in the more south regions warmer water from atlantic, pacific and the mild air from snowfree land has a much bigger impact.
But the  point is. If no ice means more ice the next year, then ice is  warming, so all the time when ice cover was big, the ice avoided the arctic  ocean to supercool down.
And another point, say if  arctic water would  be mixed, so salty,the density would be below the freezing point and so in  winter the ocean would cool down to  depth and maybe this is much more energy then the additional energy due to less albedo.
This is also noticed by some experts but very few people seems to care about,even the physic is really easy to understand. No ice arctis has more potential to eat the energy from the southern  region and send it to space.
Maybe im wrong, but this logic seems to be true.
Title: Re: The 2017/2018 freezing season
Post by: Dharma Rupa on November 13, 2017, 01:31:58 PM
More open water means higher humidity means more of the greenhouse gas H2O.
Title: Re: The 2017/2018 freezing season
Post by: Neven on November 13, 2017, 04:36:44 PM
For a belated PIOMAS update (http://neven1.typepad.com/blog/2017/11/piomas-november-2017.html) over on the ASIB, I produced this graph showing Arctic Temperatures (65-90N) for October since 2005. 2017 second lowest on record:

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fneven1.typepad.com%2F.a%2F6a0133f03a1e37970b01b8d2bdd347970c-800wi&hash=5249414458b9e365d815986dc296694f)
Title: Re: The 2017/2018 freezing season
Post by: 2phil4u on November 13, 2017, 05:04:16 PM
More water = more greenhouse effect ?
Is this allways true, more clouds means more snow, snow warms the cloud and cool earth with the cool water.
Sure if cloud gets warmer the energy is from the surface, so there is an energy change.
And the clouds energy will not be reflected as much as ir radiation from earth.
This is very simplificated, im also not an expert,  but clouds also reflect sunlight direct to space.
So many effects.
I dont want to underplay the climate effect, i only think climate sensitiy is propably at the lower end.
But we need to slow down co2, simply build renewables worldwid with some treaty that partners have to buy energy for some decades, so we can get the money back we invested at beginning, because prices will drop rapidly if we start to really build many.
Would  be an idea, take money, build reneables, get less money then invested,  price goes down, now the partner has to buy longer, so we can get the money back because we allready produce under the price handled out.
Money can be taken as a credit from central banks.
Title: Re: The 2017/2018 freezing season
Post by: A-Team on November 13, 2017, 05:42:13 PM
Below is an update on Arctic Ocean open water from the 10 Sept minimum (fixed black outline) until 12 Nov with relative areas of ice-free regions for later dates (inset bar graph), with emphasis on the Chukchi-Beaufort and north Svalbard. Interior green represents 100% sea ice concentration in the UH AMSR2 assessment; there is little else this time of year except on the periphery.

The second animation compares 12 Nov 17 to the same date in 2013-2016. The magenta line shows the union of open water for these five years; 2012 data is not available at UH until the first of January. The multiplier relative to the low year 2013 and relative to five year mean are also provided.

year   rel 2013   rel mean
2017   1.88   1.27
2016   1.53   1.04
2015   1.32   0.90
2014   1.64   1.11
2013   1.00   0.68
Title: Re: The 2017/2018 freezing season
Post by: oren on November 13, 2017, 10:15:07 PM
A-Team thank you for these wonderful animations. I had a "feeling" that 2017 was refreezing much better than 2016, but it seems on the Chukchi front that is not the case.
Title: Re: The 2017/2018 freezing season
Post by: A-Team on November 13, 2017, 10:33:59 PM
Quote
on the Chukchi front, refreezing is actually the slowest in years. while the Svalbard front is actually receding poleward.
That's right, Oren. It appears primarily attributable to influxes of Bering Sea and Atlantic Waters that are too warm, given their immense heat capacity relative to the freezing capacity of cold air in conjunction with net upwelling radiative energy flux loss. (Ice pack bulk motion, compaction and dispersion need to be factored in but have been fairly minimal.)

The 3.125 km resolution of UH AMSR2 sea ice concentration (previous post) does a better job at picking out open water than far coarser satellite data used elsewhere for the less intuitive extent/area graphs, especially as coastal complexity comes into play. However those have the longer history necessary to pull trends from natural variability. In my view, picking connected open water in this region is more appropriate than ad hoc regional definitions of Beaufort vs Chukchi vs East Siberian seas.

The UH SMOS sea ice thickness product below uses a quite different approach that is complementary to AMSR2 sea ice concentration. At the very margins of the ice pack where new ice is in the initial stages of formation, SMOS provides the opportunity to apply a specific thickness and brine content cutoff for what is to be considered as defining the effective ice edge. As depicted in the second animation, the thickness, salinity and snow surface temperatures have slightly different edges.

The freezing point of sea water at 34 psu salinity is -1.8ºC which corresponds to 271.35 on the kelvin scale shown. (While not considered politically correct today, ºK was used for the first 149 years for this scale, including by Kelvin himself.) Bulk ice salinity increases towards the edges and markedly so for ice age due to progressive brine exclusion.
Title: Re: The 2017/2018 freezing season
Post by: Hyperion on November 14, 2017, 03:58:14 AM
Here's the data from the only warm buoy still functioning. At:
LAST UPDATE
Date: 11/13/2017
Position: 76.04N 147.81W
Battery Voltage: 11.40V
She appears to have done a small pirouette around the remnant of the Beaufort gyre since august and is currently about where the ice edge retreated to in September. This is probably the best place and time of year for the persistence of a low salinity lid in the whole Arctic. But between the surface and 50m where the shelf of pacific heat is is a scant 1 to 2 psu differential. With both extremes of depth experiencing excursions to around the 29psu point. The exclusion of salt from a metre of ice is sufficient to raise 30m of surface layer by a psu in salinity. This is I fear a tipping point upon us where the thermal inertia of the deep basin mixed layer precludes bottom thickening and little more than floating snow can be expected as a winter sea ice state. The Chukchi and Svalbard surge and retreat behaviour certainly looks to me like the halo has lost the strength to submerge pacific and Atlantic warm surges below the hurt zone.
Title: Re: The 2017/2018 freezing season
Post by: Niall Dollard on November 14, 2017, 08:38:12 AM
For a belated PIOMAS update (http://neven1.typepad.com/blog/2017/11/piomas-november-2017.html) over on the ASIB, I produced this graph showing Arctic Temperatures (65-90N) for October since 2005. 2017 second lowest on record

Thanks Neven. But i would have phrased it as second highest on record.  :)

Troposphere warmed a lot in October going by Spencer's UAH data.
https://forum.arctic-sea-ice.net/index.php/topic,1225.msg133396.html#msg133396
Title: Re: The 2017/2018 freezing season
Post by: A-Team on November 14, 2017, 12:43:43 PM
Quite a change ... one of our long-time resources for sea ice thickness has been replaced. The ice is markedly thinner in the new products; whether it is any more accurate is questionable. Still, the forecasts give some idea what is coming.

The animations show the Beaufort barely closing over, the Chukchi and Svalbard remaining open and some moderate Fram export, to 20 Nov.

Quote
As of 30 Sept 2017, ACNFS will be replaced by the Global Ocean Forecast System (GOFS 3.1). Daily Arctic and Antarctic ice products are available from the GOFS 3.1web page. The ACNFS webpage will remain in service for historical purposes but will not be updated with real-time ice forecast products.

https://www7320.nrlssc.navy.mil/GLBhycomcice1-12/POLAR.html
Title: Re: The 2017/2018 freezing season
Post by: Sterks on November 14, 2017, 02:45:02 PM
Quite a change ... one of our long-time resources for sea ice thickness has been replaced. The ice is markedly thinner in the new products; whether it is any more accurate is questionable. Still, the forecasts give some idea what is coming.

Unless they have improved something very recently, this model is absolutely unreliable, it shows such a thin ice, (especially in summer), that nothing else out there supports or aligns with, whether PIOMAS, Cryosat, SMOS, or just what we have been seeing from the buoys or the Healy.

Expect however some extremely avid followers of this Glb thing in summer. A pity, the Acnfs of the last two or three years did not behave bad at all (for ice thickness; for ocean in general dont know, but probably this is an improvement, otherwise what's the point).

Title: Re: The 2017/2018 freezing season
Post by: gerontocrat on November 14, 2017, 02:56:36 PM
This from cci-reanalyzer is quite impressive. It has been the same for some considerable time except now the Atlantic end high +ve temp anomalies is pushing into very high latitudes.

And this image from NSIDC (as at 12 Nov) seems to show a good correspondence between +ve , -ve, and 0 temp anomalies and where sea ice extent is above, below and average (whereupon A-team tells me it is sea temperatures at surface and depth that really matter ?).
Title: Re: The 2017/2018 freezing season
Post by: Dharma Rupa on November 14, 2017, 04:22:11 PM
(whereupon A-team tells me it is sea temperatures at surface and depth that really matter ?).

I would think that it is water vapor which is immediate cause, with ocean temperature at depth as the ultimate cause.
Title: Re: The 2017/2018 freezing season
Post by: A-Team on November 14, 2017, 04:32:37 PM
Quote
is GOFS an improvement, otherwise what's the point?
Good question. Ditto for RASM-ESRL which seems to offer a third version of similar products (below). But that could be asked as well for UH and UB SMOS. Hamburg has coordinated salinity polarizability with Cryosat thickness; Bremen with another soil satellite SMAP. Maybe the two could get together and offer one optimal product?

http://ieeexplore.ieee.org/document/7730367/
http://www.iup.uni-bremen.de/iuppage/psa/projects/SMOSice-project.php

Quote
sea temperatures at surface and depth matter
The air temperature at 2m can be quite cold relative to the sea water freezing point yet the re-analyzer temperature anomaly can still be a pronounced orange, especially for a 30 year base period that misses out on more recent Arctic Amplification (which is largely a fall and winter phenomenon).

Actually the temperatures of physical interest to the freeze season are those directly observable of the water and snow/ice surfaces themselves, not modeled meteorological 2m, though the three strongly influence each other.

Seductive computer graphics in many instances have gotten far ahead of actual data accuracy. Only a handful of products, such as UH SMOS, contain error analysis maps in their netCDF bundle. It is not rocket science, using 3rd party ImageJ 3D surface plugins, to drape say ice thickness over its error bump map, both as time series.

Note some open water north of the Bering Strait is still 3ºC above the freezing point. Given wind mixing (shown), thin dry air has a lot of work to do before stable frazil ice can form. Meanwhile upwelling net longwave cooling (provided by ESRL in Arctic11.gif, Arctic23.gif, and Arctic14.gif) is another consideration.

For all their shortcomings, we are probably better off using coupled radiative water-ice-snow-air-precip-cloud forecast models, which quantitatively integrate all the considerations, than intuiting off a single parameter such as a transient air mass.

https://www.esrl.noaa.gov/psd/forecasts/seaice/ navigate to Coupled --> Surface Fluxes

There are no active temperature gauges today in the Arctic Ocean itself, only a handful on the periphery and one daily sonde at Ny-Ålesund. This would be like producing a high resolution daily 2m temperature map of Europe using only station data from North Africa, Ireland and Finland, lol.

Quote
water vapor intrusions can have very significant impacts
Yes indeed, seems like last season had a number of notable and persistent events. Anybody recall the link to that very fine TPW web graphic? It showed counter-rotating water vapor trails sometimes rising up into the North Atlantic and beyond, bring warm vapor from the Caribbean.

Winter storms have been analyzed by L Boisvert and coworkers, including in several AGU2017 abstracts, notably:

GC43J-07: Increasing frequency and duration of Arctic winter warming events
http://onlinelibrary.wiley.com/doi/10.1002/2017GL073395/full open source
https://www.researchgate.net/profile/Linette_Boisvert/contributions
RM Graham et al

During the last three winter seasons, extreme warming events were observed over sea ice in the central Arctic Ocean. Each of these warming events were associated with temperatures close to or above 0°C, which lasted for between 1 and 3 days. Typically temperatures in the Arctic at this time of year are below −30°C. Here we study past temperature observations in the Arctic to investigate how common winter warming events are. We use temperature observations from expeditions such as Fram (1893–1896) and manned Soviet North Pole drifting ice stations from 1937 to 1991. These historic temperature records show that winter warming events have been observed over most of the Arctic Ocean.

Despite a thin network of observation sites, winter time temperatures above −5°C were directly observed approximately once every 3 years in the central Arctic Ocean between 1954 and 2010. Winter warming events are associated with storm systems originating in either the Atlantic or Pacific Oceans. Twice as many warming events originate from the Atlantic Ocean compared with the Pacific. These storms often penetrate across the North Pole. While observations of winter warming events date back to 1896, we find an increasing number of winter warming events in recent years.

Record low Arctic sea ice extents were observed during the last three winter seasons (March). During each of these winters, near-surface air temperatures close to 0°C were observed, in situ, over sea ice in the central Arctic. Recent media reports and scientific studies suggest that such winter warming events were unprecedented for the Arctic. Here we use in situ winter (December–March) temperature observations, such as those from Soviet North Pole drifting stations and ocean buoys, to determine how common Arctic winter warming events are.

Despite a limited observational network, temperatures exceeding −5°C were measured in situ during more than 30% of winters from 1954 to 2010, by either North Pole drifting stations or ocean buoys. Correlation coefficients between the atmospheric reanalysis, ERA-Interim, and these in-situ temperature records are shown to be on the order of 0.90.

This suggests that ERA-Interim is a suitable tool for studying Arctic winter warming events. Using the ERA-Interim record (1979–2016), we show that the North Pole typically experiences 10 warming events (T2m > −10°C) per winter, compared with only five in the Pacific Central Arctic (PCA).

C21B-1119: Winter Arctic sea ice growth: current variability and projections for the coming decades
https://agu.confex.com/agu/fm17/meetingapp.cgi/Paper/258297

C33C-1215: Rainy Days in the New Arctic: A Comprehensive Look at Precipitation from 8 Reanalysis
https://agu.confex.com/agu/fm17/meetingapp.cgi/Paper/253439
Title: Re: The 2017/2018 freezing season
Post by: Neven on November 14, 2017, 11:11:12 PM
Thanks Neven. But i would have phrased it as second highest on record.  :)

Absolutely right you are!

Yes indeed, seems like last season had a number of notable and persistent events. Anybody recall the link to that very fine TPW web graphic? It showed counter-rotating water vapor trails sometimes rising up into the North Atlantic and beyond, bring warm vapor from the Caribbean.

You mean this one (link (http://tropic.ssec.wisc.edu/real-time/mtpw2/webAnims/tpw_nrl_colors/global2/mimictpw_global2_latest.gif) in case image doesn't show)?

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Ftropic.ssec.wisc.edu%2Freal-time%2Fmtpw2%2FwebAnims%2Ftpw_nrl_colors%2Fglobal2%2Fmimictpw_global2_latest.gif&hash=0a761f988655e9fa66fef0fc2525c422)
Title: Re: The 2017/2018 freezing season
Post by: A-Team on November 14, 2017, 11:50:24 PM
Quote
You mean this TPW?
Yes! Surprising that it display, original size is 1000 x 470

Turns out they offer quite a few specialized views, though not either pole. I found the netCDF files but they are not in the Geo2D format that would allow re-projection in Panoply with a more attractive palette (though Zack seems to have found a way of doing this.) It would be feasibly to string together multiple days, though they set everything at 100ms delay and then use multiples of first and last rather than setting ms properly.

http://tropic.ssec.wisc.edu/real-time/mtpw2/webAnims/tpw_nrl_colors/ archive
https://tinyurl.com/h4z357y front page
   
alaska
ausf
conus
diag_conus
diag_global
epac
europe
global
global2
indo
namer
natl
samer1
samer2
wpac
Title: Re: The 2017/2018 freezing season
Post by: Hyperion on November 15, 2017, 01:19:11 AM
A few specific and latent heat of fusion calculations to get a handle on the magnitude of effects we can expect from an expanding surface mixed salinity layer:

At 0 deg C one gram of seawater has to absorb 4.000 Joules of heat for the temperature to increase 1 degree celsius (°C).

Density is 1028 grams per litre so 4.112 kiloJoules is required to raise 1 litre 1 degree C.

Latent heat of fusion water is 334 kJ/kg

334kJ/4.112J = 81.23 dM = 8m of depth dropped 1degC for equivalent energy release to freeze 10cm of water.

If the temp drop required is 3.2 degC to -1.8 degC = 5 degC
then 80m/5 = 16m cooled is equal to 1m of ice frozen.

If its a 2 degC drop to -1.8 freezing point
then 80/2= 40m cooled is equivalent to a metre of ice freezing.

So even at an 0.2 degC average temp a 100m salinity mixed layer would require the equivalent energy removed to cool to the point ice can exist as is released by 2.5m of water becoming frozen into about 2.75m ice.

Unless I'm mistaken, the salt-water its floating in has to be at freezing point for its salinity,
for freshwater ice or snow not to be dissolved by it? ie/ bottom melt.
Title: Re: The 2017/2018 freezing season
Post by: Hyperion on November 15, 2017, 01:21:49 AM
Hey A-team.

Quote
There are no active temperature gauges today in the Arctic Ocean itself,

does IMB 2017B count?
Title: Re: The 2017/2018 freezing season
Post by: Dharma Rupa on November 15, 2017, 02:20:27 PM
You mean this one?

You might also mention that it's the one linked at the bottom of your Arctic Sea Ice Graphs.
Title: Re: The 2017/2018 freezing season
Post by: Neven on November 15, 2017, 05:31:49 PM
You might also mention that it's the one linked at the bottom of your Arctic Sea Ice Graphs.

It's the one linked at the bottom of my Arctic Sea Ice Graphs.


 ;)  :P
Title: Re: The 2017/2018 freezing season
Post by: A-Team on November 15, 2017, 06:52:54 PM
Quote
does IMB 2017B count?
Not if it wasn't used in producing the 2m Tropical Tidbits temperature model map. If independent, it  has some interest in terms of a reality check (validation point) for the later, though one point per 9 million sq km is rather sparse. Whatever, 2m is not what the snow/ice surface is experiencing which is 0.1m or better, Teff.

Improving the effective temperature estimation over sea ice using low frequency microwave radiometer data and Arctic buoys

https://tinyurl.com/yasghcmu  10 Nov 17 EUMET OSISAF

Looking at the polarview Svalbard anomaly map that has made numerous appearances here, note that the area for which it is defined makes little sense today to the south, as even in mid-February these days ice doesn't get at all close to that boundary. However the areal definition does fairly well in excluding Fram ice yet including the Yarmak Plateau that is important to bringing Atlantic Water up from depth.

Open water in the Chukchi is following the bathymetry fairly well (as expected for Bering Sea waters), including a protrusion into the Chukchi Borderlands. However west of Herald Canyon, the influence is non-evident (eg in the ESAS west of Wrangel).

http://polarview.met.no/Statistics/climatology.html
Title: Re: The 2017/2018 freezing season
Post by: Niall Dollard on November 15, 2017, 09:40:37 PM
Warm winds also feeding up through the Bering Strait into the Chukchi. This has been a frequent pattern this autumn. Whatever happened to the Aleutian Low  (https://en.wikipedia.org/wiki/Aleutian_Low) ? I guess semi-permanent is not all that permanent.

Warm SE flow also persisting north of Svalbard - however the same large blocking high pressure responsible, centred currently near Cape Chelyuskin, is feeding in some very low temperatures over the Kara Sea.

Not surprising then that ESRL is forecasting considerable ice development over the Kara in the next 5 days.
Title: Re: The 2017/2018 freezing season
Post by: Brigantine on November 17, 2017, 10:07:25 PM
Ice reported in Black Bay (Ontario shore of Lake Superior) by both CIS and GLSEA on Nov 16.

From what I can figure it's the 2nd earliest reported great lakes ice on record (since 1972/3 season). 2014 was 2 days earlier, 1995 was one day later.

All years with November ice: '95 '96 '05 '07 '12 '13 '14 '15 '17 - Correlated with decreasing arctic ice?
Title: Re: The 2017/2018 freezing season
Post by: Niall Dollard on November 18, 2017, 12:18:57 AM
Ice reported in Black Bay (Ontario shore of Lake Superior) by both CIS and GLSEA on Nov 16.

From what I can figure it's the 2nd earliest reported great lakes ice on record (since 1972/3 season). 2014 was 2 days earlier, 1995 was one day later.

All years with November ice: '95 '96 '05 '07 '12 '13 '14 '15 '17 - Correlated with decreasing arctic ice?

Not sure if I follow what you mean by decreasing arctic ice? 12 and 07 were low arctic ice years but 1996 had substantial arctic ice all through the summer (the min was in the top 5 highest in the satellite era).

Over on the other side of the Atlantic, the Baltic has started its freeze. Early days yet. The SSTs through much of the Baltic are running circa 1 C above the 1971-2000 norm (denoted by the circled temps in chart attached).
Title: Re: The 2017/2018 freezing season
Post by: Brigantine on November 18, 2017, 06:44:17 AM
True, 1996 doesn't fit. But '95, '05, '07 and '12 all had the lowest September volume on record at the time, and by a clear margin.

Though many other record years aren't on the list, and after 2012 the rules seem to change - and that's half the data.
Title: Re: The 2017/2018 freezing season
Post by: Niall Dollard on November 18, 2017, 09:47:29 AM
Ok.

I havent looked through all the years but correlating between warm Arctic and early cold on Lake Superior would seem to fit in very much with Jennifer Francis' wobbly jet stream research.

https://www.npr.org/sections/thetwo-way/2014/02/16/277911739/warming-arctic-may-be-causing-jet-stream-to-lose-its-way
Title: Re: The 2017/2018 freezing season
Post by: Neven on November 18, 2017, 10:06:59 PM
I've been playing a bit with temperature data from the NCEP reanalysis dataset (here (https://www.esrl.noaa.gov/psd/cgi-bin/data/timeseries/timeseries1.pl)), so I can start using monthly temperature graphs for the PIOMAS updates on the blog, or some such.

I've divided the Arctic (65-90N) into four sections:

Siberian 75-165 E
Pacific 165-210 E
American 210-330E
Atlantic 330( or -30)-75 E

Here are graphs for October 2005-2017 and 1948-2017:
Title: Re: The 2017/2018 freezing season
Post by: Shared Humanity on November 18, 2017, 11:17:49 PM
A general warming trend over the last 4 decades.
Title: Re: The 2017/2018 freezing season
Post by: Sterks on November 18, 2017, 11:55:36 PM
 Look at those isobars. Extremely windy these next days in the Central Arctic, very cold in Siberia, not really in the Atlantic sidem
Title: Re: The 2017/2018 freezing season
Post by: Niall Dollard on November 19, 2017, 02:04:32 AM
Look at those isobars.
Have to say i dont like 2 hPa spacing on large charts. Gives a wrong impression.

Extremely windy these next days in the Central Arctic

? Central Arctic will be dominated by a large anticyclone
Title: Re: The 2017/2018 freezing season
Post by: oren on November 19, 2017, 08:02:22 AM
I've been playing a bit with temperature data from the NCEP reanalysis dataset

I've divided the Arctic (65-90N) into four sections:

Here are graphs for October 2005-2017 and 1948-2017:
Thank you Neven, very interesting. It seems 2016 automn "craziness" was mostly in the Pacific sector, which also shows the strongest long-term warming trend.
Title: Re: The 2017/2018 freezing season
Post by: Shared Humanity on November 19, 2017, 02:12:55 PM
I've been playing a bit with temperature data from the NCEP reanalysis dataset

I've divided the Arctic (65-90N) into four sections:

Here are graphs for October 2005-2017 and 1948-2017:
Thank you Neven, very interesting. It seems 2016 automn "craziness" was mostly in the Pacific sector, which also shows the strongest long-term warming trend.

It does look as if some shift occurred around 2000 in all regions. All are warmer with the shift more noticeable in the Pacific and Atlantic sectors.
Title: Re: The 2017/2018 freezing season
Post by: A-Team on November 19, 2017, 03:50:53 PM
For a comprehensive summary of 2017, if a 288 page document can be called a summary, there is a quite decent report at the link below. The cover picture of the ice edge, a fraction of which is shown below, tells the story in brief.

Snow, Water, Ice and Permafrost in the Arctic (SWIPA) 2017
Arctic Monitoring and Assessment Programme (AMAP), Oslo, 2017
http://www.amap.no/documents/download/2987

Arctic temperatures are rising faster than the global average. The Arctic was warmer from 2011 to 2015 than at any time since instrumental records began in around 1900, and has been warming more than twice as rapidly as the world as a whole for the past 50 years. January 2016 in the Arctic was 5°C warmer than the 1981–2010 average for the region, a full 2°C higher than the previous record set in 2008, and monthly mean temperatures in October through December 2016 were 6°C higher than average for these months. Sea temperatures are also increasing, both near the surface and in deeper water.

Except for the coldest northern regions of the Arctic Ocean, the average number of days with sea ice cover in the Arctic declined at a rate of 10–20 days per decade over the period 1979–2013, with some areas seeing much larger declines. Warm winds during the autumn of 2016 substantially delayed the formation of sea ice.

The area and duration of snow cover are decreasing. Snow cover has continued to decline in the Arctic, with its annual duration decreasing by 2–4 days per decade. In recent years, June snow area in the North American and Eurasian Arctic has typically been about 50% below values observed before 2000.

Permafrost warming continues. Near-surface permafrost in the High Arctic and other very cold areas has warmed by more than 0.5°C since 2007–2009, and the layer of the ground that thaws in summer has deepened in most areas where permafrost is monitored.

Freshwater storage in the Arctic Ocean has increased. Compared with the 1980–2000 average, the volume of freshwater in the upper layer of the Arctic Ocean has increased by 8,000 cubic kilometers, or more than 11%.  is volume equals the combined annual discharge of the Amazon and Ganges rivers, and could—if it escapes the confines of the Arctic Ocean—affect circulation in the Nordic Seas and the North Atlantic.

Arctic climate trends affect carbon storage and emissions. New estimates indicate that Arctic soils hold about 50% of the world’s soil carbon. While thawing permafrost is expected to contribute significantly to future greenhouse gas emissions, the amount released over the past 60 years has been relatively small.

The impacts of Arctic changes reach beyond the Arctic. In addition to the Arctic’s role in global sea-level rise and greenhouse gas emissions, the changes underway appear to be affecting weather patterns in lower latitudes, even influencing Southeast Asian monsoons.

Warming trends will continue. Models project that autumn and winter temperatures in the Arctic will increase to 4–5°C above late 20th century values before mid-century, under either a medium or high greenhouse gas concentration scenario. This is twice the increase projected for the Northern Hemisphere.  These increases are locked into the climate system by past emissions and ocean heat storage, and would still occur even if the world were to make drastic near-term cuts in emissions.
Title: Re: The 2017/2018 freezing season
Post by: Dharma Rupa on November 19, 2017, 05:02:05 PM
A general warming trend over the last 4 decades.

Looks more to me like the continents are flat while the oceans are warming -- though the Pacific is more variable than the Atlantic.
Title: Re: The 2017/2018 freezing season
Post by: Neven on November 19, 2017, 06:00:25 PM
Looks more to me like the continents are flat while the oceans are warming -- though the Pacific is more variable than the Atlantic.

It's definitely warming faster on the ocean sides (which makes sense), but over land it's not exactly flat either:
Title: Re: The 2017/2018 freezing season
Post by: Neven on November 19, 2017, 06:01:09 PM
Of course, that's assuming I didn't make any mistakes (I've made them before when working with this dataset).
Title: Re: The 2017/2018 freezing season
Post by: numerobis on November 19, 2017, 06:58:54 PM
Look at those isobars. Extremely windy these next days in the Central Arctic

We're looking at winds 70 km/h gusting to 90 km/h tomorrow morning in Iqaluit, and ECMWF suggests it's going to get worse Monday night into Tuesday morning. Iqaluit is, by local standards, isolated from the worst winds: Kimmirut and the communities in Nunavik and Kivaliq will be getting the brunt of the storm.

Temperatures started climbing last night. They should hit above freezing on Tuesday, when we expect rain. We were just getting into some good ski conditions, too.

The inlet is frozen enough for a polar bear to walk on (one was spotted this morning). At the edge of the inlet, a fuel tanker is filling up our tanks (we thought the one two weeks ago would be the last, but no, there was one more). On Thursday it stopped just past the edge of the ice; by yesterday it was encased in grey ice.
Title: Re: The 2017/2018 freezing season
Post by: Shared Humanity on November 19, 2017, 10:41:40 PM
A general warming trend over the last 4 decades.

Looks more to me like the continents are flat while the oceans are warming -- though the Pacific is more variable than the Atlantic.

Are we looking at the same charts?

Since 2002, the colder years for both Siberia and North America are more like the warmer years from the previous century.

Siberia:

1991 to 2000: 5 of 10 years with temps below -11C.
2001 to 2016: 1 of 16 year with temps below -11C.

1991 to 2000: 3 of 10 years with temps higher than -10C.
2001 to 2016: 13 of 16 years with temps higher than -10C.
Title: Re: The 2017/2018 freezing season
Post by: Brigantine on November 20, 2017, 12:46:49 AM
Freshwater storage in the Arctic Ocean has increased. Compared with the 1980–2000 average, the volume of freshwater in the upper layer of the Arctic Ocean has increased by 8,000 cubic kilometers
Do you know if that includes freshwater *ice*?

It's on the same scale as the ~10,000km^3 decrease in sea ice, so is the *liquid* freshwater up 8,000 or ~17,000?
(and so the total liquid+ice fresh water down ~1,000 or up 8,000 GT)
Title: Re: The 2017/2018 freezing season
Post by: A-Team on November 20, 2017, 03:42:43 PM
Quote
Do you know if that includes *freshwater* ice?
There's a comprehensive and quite readable discussion of every aspect of Arctic freshwater in Chapter 7 of the assessment. By freshwater, oceanographers don't mean drinking water fresh, merely how not-as-saline as 34.8 psu seawater. So 34.7 psu is already freshened by how much water would have to evaporate to bring it up to 34.8 psu. The surface freshwater anomaly extends down a few tens of meters at most (first image).

First year ice is still quite salty -- not single ice crystals per se which are standard ice Ih with no inclusions -- but from extruded salt in brine channels that's still around. Thus the Russian 'Barneo' expedition this year had to melt snow to get their drinking water. By some accounts, a 2:3 mix of salt:fresh is utilizable by humans.

Below, some scattered snippets from Chapter 7. The attached figures are better viewed in the original.

Snow, Water, Ice and Permafrost in the Arctic (SWIPA) 2017
Arctic Monitoring and Assessment Program (AMAP), Oslo, 2017 [cutoff date mid-2016]
http://www.amap.no/documents/download/2987

The Arctic water cycle is expected to continue to intensify during this century. Mean precipitation and daily precipitation extremes will increase over mid- and high latitudes, with implications for the management of water resources, flow of freshwater into the Arctic Ocean, changes in sea ice temperature, and amplification of regional warming (through reduced surface reflectivity caused by a shift from snow to more rain in the warmer seasons).
 
The areal reduction of old sea ice has consequences for mean sea-ice thickness, thickness distribution, and surface roughness of Arctic sea ice (Hansen et al., 2014; Renner et al., 2014; Landy et al., 2015). Reduced ice thickness is related to changes in the forcings, whereas changes in thickness distribution are directly related to the properties of the different ice classes present.

Younger sea ice has on average higher salinity than older ice, and this has various consequences, for example how much freshwater is transported with drifting ice and on habitat conditions for organisms living within the ice.

A shift from perennial sea ice to predominantly seasonal ice types will cause changes in the physical properties of the ice cover. These changes are mainly associated with the volume of brine trapped within the ice. In contrast to first-year ice, multi- year ice has undergone a summer melt season and in the process lost most of the brine trapped within.

The brine volume, which can be calculated as a function of salinity and temperature, determines the porosity of the ice, which controls many important properties of sea ice, such as its strength, thermal and dielectric properties, mass (chemical and gas) transport, and the development of melt ponds and surface albedo.

Salt and heat fluxes are affected by the increased presence of first-year sea ice. First-year ice growth rates are higher than for older ice types, which means more salt is released during autumn and winter ice growth. In summer, the higher melt rates for first- year ice increases freshwater input to the surface ocean, thereby increasing buoyancy flux and stratification. Gas exchange rates through sea ice are also changing: more saline ice means more active exchange processes because gas permeability is higher in more porous sea ice.

In contrast to the southern hemisphere, the configuration of continents in the northern hemisphere is such that they effectively capture moisture from the atmospheric storm tracks of the Westerlies and redirect in north-flowing drainage basins disproportionate quantities of freshwater into the Mediterranean configuration of the Arctic Ocean (Figure 7.1).

Hence, while the Arctic Ocean represents only 1% (in terms of volume) and 3% (in terms of surface area) of the global ocean, it collects over 11% of the global river discharge (Dai and Trenberth, 2002; Carmack et al. 2016). e Trade Winds also transport moisture from the Atlantic Ocean across the Isthmus of Panama to freshen the Pacific Ocean, and some of this freshened water eventually flows into the Arctic Ocean through Bering Strait. e resulting salt stratification or halocline (i.e. a freshened upper ocean and salinity increasing with depth) is the dominant characteristic of high-latitude seas in general and the Arctic Ocean in particular .

The freshwater budget of the Arctic Ocean is governed by the system’s key functions and processes: the delivery of fresh and low-salinity waters to the Arctic Ocean by river inflow, net precipitation, distillation during the freeze/thaw cycle and Pacific Ocean inflows;

The Arctic Ocean freshwater budget was recently updated by Haine et al. (2015) (Table 7.1). The distribution of freshwater within the Arctic Ocean is heterogeneous and controlled by circulation and water mass structure. The Arctic Ocean is made integral to the global ocean by the northern hemisphere thermohaline circulation which drives Pacific Water through Bering Strait into Canada Basin, and counter-flowing Atlantic Water through Fram Strait and across the Barents Sea into Nansen Basin.

Following Bluhm et al. (2015), it is useful to recognize four vertically-stacked circulation layers (Figure 7.5): (1) the wind- driven surface layer circulation that is characterized by the cyclonic Trans-Polar Dri from Siberia to Fram Strait and the anticyclonic Beaufort Gyre in southern Canada Basin; (2) the underlying circulation of waters that comprise the halocline complex, composed largely of Pacific Water and Atlantic Water that are modified during their passage over the Bering/ Chukchi and Barents/Siberian shelves, respectively; (3) the topographically-trapped Arctic Circumpolar Boundary Current that carries Atlantic Water cyclonically around the boundaries of the entire suite of basins; and (4) the very slow exchange of Arctic Ocean Deep Waters.

Within the basin domain two water mass assemblies are observed, the difference between them being the absence or presence of Pacific Water sandwiched between Arctic Surface Waters above and the Atlantic Water complex below; the boundary between these domains forms the Atlantic/Pacific halocline front.
 
But the distribution of freshwater within the Arctic Ocean is not uniform, and salinities range from about 35 where Atlantic Water enters the basin to near zero adjacent to river mouths and along the coast (Carmack et al., 2016). is huge range in salinity, the main parameter that determines density stratification in high-latitude oceans, affects almost every aspect of circulation and mixing within the Arctic Ocean.

Relative to a reference salinity of 34.8, about 101,000 km3 of freshwater are stored in the Arctic Ocean (this is an estimate of the 2000–2010 annual average volume by Haine et al., 2015; Table 7.1). The largest freshwater reservoir exists in the Amerasian Basin, specifically in the Beaufort Gyre where about 23,500 km3 freshwater are stored and the accumulated freshwater anomaly diluting the upper ocean above the 34.8 isohaline surface is about 20 m thick. In the Eurasian Basin, typical liquid freshwater thicknesses are 5–10 m.

Freshwater in the solid phase as sea ice is another important reservoir in the Arctic. About 14,300 km3 of freshwater are stored in sea ice (2000–2010 average from Haine et al., 2015). e largest sea ice volumes are north of the Canadian Arctic Archipelago and Greenland and across the pole, where the ice is still relatively thick (Kwok et al., 2009).

The seasonal freeze-thaw cycle acts to exchange freshwater between the liquid and solid phases. Its amplitude is about 13,400 km3 (averaged over the decade of the 2000s; Haine et al., 2015), close to the annual average freshwater volume stored in sea ice. Sea-ice formation in winter occurs throughout the Arctic Ocean but the prevailing currents tend to export ice frozen over the Eurasian shelves toward the central Arctic and the Trans-Polar Drift (Figure 7.5).

Under current climate conditions only about 35% of the sea ice present at the end of winter, when the ice volume peaks survives the summer to become multiyear ice. Of the remaining 65%, most melts within the Arctic although some is exported south.

Kwok and Rothrock (2009) reported submarine and satellite data that show the average end-of-melt season ice thickness was 3.02 m in 1958–1976 but just 1.43 m in 2003–2007. Because both ice extent and ice thickness are declining, sea-ice volume is also declining.

Currently, the Arctic Ocean is freshening (Haine et al., 2015), warming (Polyakov et al., 2012), losing sea ice (Stroeve et al., 2012), and its ice cover is changing properties and moving faster (Kwok et al., 2013).
Title: Re: The 2017/2018 freezing season
Post by: Brigantine on November 20, 2017, 10:57:46 PM
Table 7.1
Resevoir / 1980-2000 / 2000-2010 / Change (km^3)
Liquid FW / 93,000 / 101,000 / +8,000
Sea ice / 17,800 / 14,300 / -3,500
Total FW / 110,800 / 115,300 / +4,500

So in fewer words: No.

But I also didn't realize that the 8,000 km^3 figure is only up to the 2010's, not 2017. So the reduction in sea ice volume is comparatively less significant than I thought anyway.
Title: Re: The 2017/2018 freezing season
Post by: Niall Dollard on November 21, 2017, 10:04:36 PM
Some warm air moving up Baffin at the moment (as Numerobis mentioned already) spreads further north over the next couple of days. Especially so at the upper level. By Friday the models are showing a pool of very warm air settled over the northwest of Ellesmere. Often one of the coldest spots in the northern hemisphere.

The ECMWF model is showing upper air temps above zero at 850 hPa (circa 1500m) level. Likely though to be more like -10 C to -15 C at the surface.

A second surge of upper warmth is progged to spread up over Greenland in about a weeks time, especially up the eastern side (although this is further out and maybe not as reliable - given current volatility in the models)
Title: Re: The 2017/2018 freezing season
Post by: Adam Ash on November 22, 2017, 03:11:37 AM
Would not warm air at 1500 metres lead to a significant increase in downward radiation and hence warming near surface?

Presumably the warm air lens at 1500 metres is in the form of an inversion layer, which would further trap warmth beneath, or at least slow outward radiation from the ice/ocean surface??
Title: Re: The 2017/2018 freezing season
Post by: Brigantine on November 22, 2017, 08:07:33 AM
This (https://www7320.nrlssc.navy.mil/GLBhycomcice1-12/navo/arcticicespddrf/nowcast/icespddrf2017112012_2017112100_929_arcticicespddrf.001.gif) very orderly pattern is not the one I was expecting to see... It almost looks like one giant rigid turntable, pivoting right on the pole.

Is this common?
Title: Re: The 2017/2018 freezing season
Post by: Niall Dollard on November 22, 2017, 08:07:48 AM
Temperature inversions are a very common feature in the high Arctic especially in the long winter period of no sun, Information on inversion trends at Eureka are shown here:

http://aolab.phys.dal.ca/publications/ao2010.pdf

This report by Bradley states that temperature inversions as large as 35 C are possible. These cases involve warm anomalous southerly airflows in mid winter. It is possible to get temperatures aloft exceeding 0 C. For several days in Jan 1977 temperatures over Alert, Resolute and Eureka all exceeded 0 C reaching +4.6 C at 1.2 km above Alert on Jan 12th when the surface temp was -15 C.

So I suppose in terms of climatology, upper air temps over 0C in winter, does happen from time to time.

www.geo.umass.edu/faculty/bradley/bradley1992d.pdf
Title: Re: The 2017/2018 freezing season
Post by: numerobis on November 22, 2017, 03:28:50 PM
Some warm air moving up Baffin at the moment (as Numerobis mentioned already) spreads further north over the next couple of days.

+3 C yesterday and rain in Iqaluit. Pretty much massacred our snow.

Interesting tidbit: it appears that CYFB can't actually record wind speeds above 100 km/h (above 40 kt it starts to go wonky). I wonder what other weather details are wrong around the Arctic.
Title: Re: The 2017/2018 freezing season
Post by: litesong on November 23, 2017, 02:25:10 AM
The High Arctic average temperature (named, Present High Arctic Berserker ;D(2), PHAB ;D(2) or FAB ;D(2) has been over average temperature for 90+ days.  So far, FAB ;D(2) has continued to exist, despite two cold fronts edging into the High Arctic, one cold front, at times, all over Canada(even Arctic Canadian islands) & one over much of Northwestern Siberia.
Title: Re: The 2017/2018 freezing season
Post by: A-Team on November 23, 2017, 06:26:37 PM
@Zlabe has a nice graphic on temperature anomalies the last couple of months, consistent with persistent open water in the Chukchi and north Svalbard (where both air and water are too warm).

The animation butts an ESRL prediction to Nov 22nd (with inset AMSR2 observational) onto an ESRL forecast to Nov 29th. The agreement of observation with forecast is so-so by its end (flashed red 22), though there are issues with fairly comparing hours and defining ice boundaries. Note that ESRL resets midway through (using some variation of AMSR2), ie it starts knowing the open boundary, goes out until its prediction ends, then gets a new observed boundary and goes out on its second round of forecast.

Overall it seems ESRL forecasts are overshooting on freeze-over; if so the Chukchi will be considerably more open than shown on Nov 29th.
Title: Re: The 2017/2018 freezing season
Post by: meddoc on November 24, 2017, 11:17:12 AM
I guess these pretty much tell the Story
Title: Re: The 2017/2018 freezing season
Post by: JayW on November 24, 2017, 11:46:57 AM
Look at those isobars. Extremely windy these next days in the Central Arctic, very cold in Siberia, not really in the Atlantic sidem

I can't really add much, except a new resource. (Unless someone has already posted these which I didn't see)

  I'm not really a fan of Ryan Maue, but he left weatherbell and is working with a new site called WeatherDotUS.  It has more ECMWF data, all freely accessible in 6 hour increments.

For the deterministic ECMWF, it has an Arctic view and these parameters. 

MSLP
10m winds. (first attachment)
850mb wind
300mb winds
850mb temp anomaly
500mb height anomaly
Total precipitation
Precipitable water venues
Modeled snowfall
2m temp anomalies


http://wx.graphics/models/ecmwf/ecmwf.php


And they also have the ECMWF 51 member ensemble system, with 6 hour increments, and out to 360 hours (although, forecasts at such lead times have questionable value)

Unfortunately, no arctic how however.

Parameters are

500mb height anomaly.
500mb height normalized anomaly
850mb temp anomaly
2m temp anomaly  (second attachment)
MSLP anomaly
Precipitation


http://wx.graphics/models/ecmwf/eps.php
Title: Re: The 2017/2018 freezing season
Post by: A-Team on November 24, 2017, 03:13:14 PM
Here is the bottom line so far for all this weather on the Bering Strait side of the pole, shown as a subtractive comparison of the last 30 days for the years 2013-2017. (The key year 2012 will not be available at UH AMSR2 for six more weeks.)

Blue: open water in both years
Yellow: open water in 2017 only
Red: open water in other year only

In the lower left corner, 2016 has more open water than 2017 on the Oct 25th initial date but as the 2017 re-freeze slows, it overtakes 2016 by Nov 23rd end date (ie more yellow than red).
Title: Re: The 2017/2018 freezing season
Post by: Niall Dollard on November 24, 2017, 06:37:44 PM

I can't really add much, except a new resource. (Unless someone has already posted these which I didn't see)

  I'm not really a fan of Ryan Maue, but he left weatherbell and is working with a new site called WeatherDotUS.


I mentioned Weather.Us alright at post #243 in this thread. I think Neven had some difficulty adding the cloudiness chart to the ASIG page.


It has more ECMWF data, all freely accessible in 6 hour increments.

For the deterministic ECMWF, it has an Arctic view and these parameters. 

MSLP
10m winds. (first attachment)
850mb wind
300mb winds
850mb temp anomaly
500mb height anomaly
Total precipitation
Precipitable water venues
Modeled snowfall
2m temp anomalies


http://wx.graphics/models/ecmwf/ecmwf.php



I hadn't seen those versions before, Thanks.  :)

Edit: I've just seen I have become an ASIF Citizen !  :)
Title: Re: The 2017/2018 freezing season
Post by: litesong on November 25, 2017, 01:41:30 AM
@Zlabe has a nice graphic on temperature anomalies the last couple of months, consistent with persistent open water in the Chukchi and north Svalbard (where both air and water are too warm).
Ah, as stated above your post.... the Present High Arctic Berserker ;D(2), PHAB ;D(2) or FAB ;D(2):
The High Arctic average temperature (named, Present High Arctic Berserker ;D(2), PHAB ;D(2) or FAB ;D(2)) has been over average temperature for 90+ days.  So far, FAB ;D(2) has continued to exist, despite two cold fronts edging into the High Arctic, one cold front, at times, all over Canada(even Arctic Canadian islands) & one over much of Northwestern Siberia.
///////
The FAB ;D(2) is now 95+ days in length, of which I predicted in its pre-60 days, that it could reach 100 days in length.
Title: Re: The 2017/2018 freezing season
Post by: Neven on November 25, 2017, 09:23:39 PM
Edit: I've just seen I have become an ASIF Citizen !  :)

Congratulations, Niall.  :)

Present High Arctic Berserker ;D(2), PHAB ;D(2) or FAB ;D(2)) has been over average temperature for 90+ days.

Here I was, thinking we had enough acronyms by now.  ;)

Quote
The FAB ;D(2) is now 95+ days in length, of which I predicted in its pre-60 days, that it could reach 100 days in length.

How does that compare to the past decade?
Title: Re: The 2017/2018 freezing season
Post by: litesong on November 26, 2017, 03:51:40 AM
 Using the JAXA High Arctic temperature line graph, I started the Present High Arctic Berserker (FAB ;D) in defiance on an anti-AGW webcyst(no misspelling). One of the deniers, who I knew on another anti-AGW webcyst, made fun of my use of Berserker, started posting dramatic paintings of Viking-like warriors & gods battling in snows & ices, calling them them Ice Berserkers.
To answer your question, long High Arctic continuous over-temperatures, during the late 1950's & early 60's were ~ 30 to 40 days. Over decades, these continuous over-temperatures very slowly increased their periods. I started paying attention to them when the over-temperatures got to 80days. Then, one of the FAB ;D 's got to one hundred days. But, it didn't stop there. One went for 140 days. In latter 2016, everyone paid attention when one FAB ;D (what I named FAB ;D(1) ) jumped to ~ 20degC over the average" temperature line. Of course, the 20degC over-temperature was quick up & down, & people quieted down, the lower the temp went. However, FAB ;D(1) went from latter 2016, deep into 2017, for over 230 days. That's one of the reasons I thought, once FAB ;D(2) got to 55-58 days in length, it had a good chance to get to  100 days (of which it is very close now). I can't say if FAB ;D(2) will get as long as FAB ;D(1), but it could if the continuing cold fronts over Canada & northwestern Siberia don't push hard into the High Arctic. Also, FAB ;D(2) started earlier than FAB ;D(1), so we'll see how long FAB ;D(2) can last.
It is no coincidence that these Present High Arctic Berserkers (FAB ;D) occur in the High Arctic during the sun periods, very low on, but mostly below the horizon.
Title: Re: The 2017/2018 freezing season
Post by: Neven on November 26, 2017, 10:29:02 AM
Quote
JAXA High Arctic temperature line graph

I'm sorry, but which graph is that?

Do you have any graphs that summarize what you just explained in words? Or the exact dates of those above average excursions? Personally, I find a measure like FDD (freezing degree days, see here (https://sites.google.com/site/cryospherecomputing/fdd)) more useful than just the period of time a trend line spends above the baseline.
Title: Re: The 2017/2018 freezing season
Post by: Jim Hunt on November 26, 2017, 01:50:17 PM
Personally, I find a measure like FDD more useful than just the period of time a trend line spends above the baseline.

Here's "Snow White's" visualisation (http://greatwhitecon.info/resources/arctic-sea-ice-graphs/#DMI-FDD) of the DMI data.

I've been meaning to produce an "improved" version (http://greatwhitecon.info/2017/07/reanalysis-of-arctic-climate/) on "her" behalf for months now, but what with one thing (http://community.prostatecanceruk.org/posts/t13034-Leo-Robot-spares-some-nerves) and another (http://www.v2g.co.uk/2017/11/static-and-mobile-distributed-energy-storage-launched-at-long-last/) that's still going to take a little while longer:

https://www.linkedin.com/search/results/content/?keywords=%23SaMDES
 
Title: Re: The 2017/2018 freezing season
Post by: litesong on November 26, 2017, 02:47:54 PM
I'm sorry that I said JAXA. It is the Danish Meteorological Institute data above the 80th parallel. Yes, you are correct that FDD is more useful(& accurate) to calculate High Arctic conditions. But, I'm mesmerized by the powerful rise of the High Arctic temperatures, that even "weather low  temperatures" over nearly 4 million square kilometers can be lifted ABOVE the average temperature line CONTINUOUSLY for nearly two thirds of a year.
 & all this High Arctic heat is occurring while the solar TSI has been languid for many decades & low for 11 years(including a 3+ year period setting a 100 year low TSI record). Wouldn't the low TSI affect the FDDs?
Maybe, I can support my post above, with some dates. Anyhow, thank you for questioning me.   
Title: Re: The 2017/2018 freezing season
Post by: Jim Hunt on November 26, 2017, 02:55:02 PM
It is the Danish Meteorological Institute data above the 80th parallel.

It would be helpful if you could include links to and/or pretty pictures of the data you are referring to. Is this the one (http://ocean.dmi.dk/arctic/meant80n.uk.php)?

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Focean.dmi.dk%2Farctic%2Fplots%2FmeanTarchive%2FmeanT_2017.png&hash=59eb65f128ffbe7ae10e4673b1a7d998)

If you need some help in how to get the right picture in the right place in your post please do not hesitate to ask. The image above is linked to the DMI web site, so it will change as the days go by.
Title: Re: The 2017/2018 freezing season
Post by: A-Team on November 26, 2017, 03:42:51 PM
It would be helpful if you would stop using emoticon-reserved text combinations in your unexplained acronyms to unlinked data. If you need some help in how to shut them off in your posts please do not hesitate to ask.

Note there are far better temperature anomaly resources than 80ºN. That does not cover -- nor serve as valid proxy for -- large areas of the Arctic Ocean which are of critical importance this time of year to the refreezing season as well as for regional ice thickening that drives the coming melt season.

In other words, given DMI 80ºN, it is impossible to infer what is going on in the Beaufort - Chukchi - ESAS area. The Arctic Ocean is not at all symmetric about the North Pole, nor is the weather. Yes, there will be a meagre R value (correlation coefficient) but the real ocean-wide data is only a click away.

DMI 80ºN has convenience as a long term record and so for displaying daily departure from trends. It's been used since forever on these forums and people here are skilled in its interpretation. However DMI 80ºN statistics have lost most of their value in the 'new Arctic' which requires a much shorter baseline to properly define unusual warmth.

Graphs lose geo-referencing. They are a relic from the past when journals charged mightily for colored maps, but not so much for line graphs with spot color. Today we have the internet and complex 2D color is free so we use maps. Journals still do not allow gif animations, 1989 standards pose their next challenge.

Using a spherical cap condenses local data to a point, ie treats it as isotropic. This is a bad idea because air and sea temperatures are strongly anisotropic near the 80ºN latitude line, primarily because of the line of islands, the nearby continental shelf break, and the bathymetry driven route of warm incoming Atlantic Waters. Thus it is not the right tool for tracking the freeze or melt seasons. For the Svalbard - SZ line, it would be far better to use a 'trapezoidal' temperature proxy of a few latitudinal degrees bounded by edge longitudes that excluded the western Fram.

The areas last to freeze are the first to melt. The seasonality of open water extent we are so exercised with expands northward from them. It is very unusual for the ice pack to have persistent and substantial internal polynyas like the one this year; at 3 km resolution, the ice pack almost always appears 'simply connected' in topological terms. Open leads are an important exception but require Sentinel-1AB resolution and massive display size.

We have not done much here with the temperature that effectively matters,Teff. This is the temperature at the ice/snow interface that is relevant to the 1D heat conduction equation through the ice to freezing the water below (or for melt pond purposes).

We should have a hundred-page forum on the heat equation but for some reason don't; it has exact solutions for many special cases of interest (including sinusoidal seasonality), not just Arctic ice, so it's well within skill sets here. For example, geothermal heat maps under Antarctica ... how do you get from observable Curie depth to the bottom of the ice: use the heat eqtn. Ditto Greenland, ESAS methane risk and so on. It's buried inside every model of ice.

https://blogs.agu.org/geospace/2017/11/13/new-antarctic-heat-map-reveals-sub-ice-hotspots/

The effective temperature is directly observed by various satellites and available daily in various netCDF files linked in earlier posts. People here generally have stronger backgrounds in meteorology and so are drawn to the two meter temperature T2m which again is convenient but only a so-so unnecessary proxy to physically relevant conditions.
Title: Re: The 2017/2018 freezing season
Post by: litesong on November 26, 2017, 04:06:04 PM
It is the Danish Meteorological Institute data above the 80th parallel.

It would be helpful if you could include links to and/or pretty pictures of the data you are referring to. Is this the one (http://ocean.dmi.dk/arctic/meant80n.uk.php)?

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Focean.dmi.dk%2Farctic%2Fplots%2FmeanTarchive%2FmeanT_2017.png&hash=59eb65f128ffbe7ae10e4673b1a7d998)

If you need some help in how to get the right picture in the right place in your post please do not hesitate to ask. The image above is linked to the DMI web site, so it will change as the days go by.
Yes, that is the one, plus all the charts going back to 1958.
Title: Re: The 2017/2018 freezing season
Post by: gerontocrat on November 26, 2017, 06:35:19 PM
I hate emoticons. They reduce emotion to poor caricature. "Shall I compare thee to an ... emoticon ?"
Title: Re: The 2017/2018 freezing season
Post by: numerobis on November 26, 2017, 07:29:55 PM
According to the ice atlas:
Quote
n Frobisher Bay, new ice formation has begun as early as mid October, and as late as the second week of November.

https://www.canada.ca/en/environment-climate-change/services/ice-forecasts-observations/publications/sea-climatic-atlas-northern-waters-1981-2010/chapter-2.html

There’s been ice in the tidal flats since the first week of November. Ice started to spread onto deeper water in the second week of November, but the storm last week wiped it out. Just as well: we just got a dump of snow, which would have insulated the ice quite effectively.
Title: Re: The 2017/2018 freezing season
Post by: A-Team on November 27, 2017, 08:47:45 AM
Here are a couple of animations of SMOS ice thickness from Oct 10th to Nov 25th. The first shows (rather low) daily thicknesses in meters and second local thickness changes from one day to the next. UH SMOS is Cryosat-aware though this set of files may not fully reflect that calibration. The widening ring of thickening ice can be seen as well as hesitant Fram export.

The 3rd animation of bulk salinity shows the progress of brine exclusion in newly forming ice. Note the ice between Svalbard and Severnaya Zemlya has not consolidated yet. The compound palette resolves similar salinities better; it is done on the tiled frames within gimp with the hue-saturation tool localized to green.
Title: Re: The 2017/2018 freezing season
Post by: seaice.de on November 27, 2017, 03:24:04 PM
A-Team, thanks for the always excellent visualization of the SMOS data!

Just a comment: the data comes with an uncertainty estimate which is unfortunately not symmetric and large for relatively thick ice. To use the data in a reasonable way is with a data assimilation system which can handle such uncertainties. For example, the Copernicus Arctic Marine Forecast System now assimilates the SMOS sea ice thickness. You can download the forecast products from the Copernicus website (select Arctic Ocean Physics Analysis and Forecast):

http://marine.copernicus.eu/services-portfolio/access-to-products/ (http://marine.copernicus.eu/services-portfolio/access-to-products/)
Title: Re: The 2017/2018 freezing season
Post by: litesong on November 27, 2017, 05:17:56 PM
To answer your question, long High Arctic continuous over-temperatures, during the late 1950's & early 60's were ~ 30 to 40 days. Over decades, these continuous over-temperatures very slowly increased their periods. I started paying attention to them when the over-temperatures got to 80days. Then, one of the FAB ;D 's got to one hundred days. But, it didn't stop there. One went for 140 days. In latter 2016, everyone paid attention when one FAB ;D (what I named FAB ;D(1) ) jumped to ~ 20degC over the average" temperature line. Of course, the 20degC over-temperature was quick up & down, & people quieted down, the lower the temp went. However, FAB ;D(1) went from latter 2016, deep into 2017, for over 230 days. That's one of the reasons I thought, once FAB ;D(2) got to 55-58 days in length, it had a good chance to get to  100 days (of which it is very close now). I can't say if FAB ;D(2) will get as long as FAB ;D(1), but it could if the continuing cold fronts over Canada & northwestern Siberia don't push hard into the High Arctic. Also, FAB ;D(2) started earlier than FAB ;D(1), so we'll see how long FAB ;D(2) can last.
It is no coincidence that these Present High Arctic Berserkers (FAB ;D) occur in the High Arctic during the sun periods, very low on, but mostly below the horizon.
I agree with Neven, that FDD data are the best way to scientifically determine High Arctic changes. But, on the AGW denier liar whiner webcysts that I oppose such, I am having real-time fun presenting the ever lengthening days of existence of continuous High Arctic over-temperatures. I show their rapid rises & falls & as surmised from the above, during low sun & sun below horizon seasons, the low falls are increasingly ABOVE the average temperature lines, established since 1958. Here is one of my posts, open to your enjoyment or critique:
Quote
litesong wrote:
Quote
litesong wrote:....FAB ;D(2) has now risen to 10degC over recorded average for the 4 million square kilometer-sized High Arctic & appears to be ~ 95 days in length. A High Arctic warm front has enveloped on the North Pole & High Arctic, with enough heat remaining to interact with the "continuing Canadian cold front" & thrusting the most northerly part of the cold front to the south. The solid cold front has been on Canada for a month (more?). But, the powerful warm front is showing it has more... "solidity".
....FAB ;D(2) has now risen to 10+degC over recorded average for the 4 million square kilometer-sized High Arctic & appears to be ~ 95+ days in length. However, the northern portion of the long term Canadian cold front may re-establish itself over the Canadian archipelago. Plus, the cold front over Northwestern Siberia is extending itself south deep into China.
FAB ;D(2) has dropped to 8degC over average temperature for the High Arctic. FAB ;D(2) appears to be very close to 100 days of existence, which was my prediction ~ 40+ days ago.... much like my posts, nurse-maiding FAB ;D(1) to its record breaking 230+ days of existence from latter 2016 to deep into 2017.
It appears FAB ;D(2) may continue well past 100 days of existence. Strong warm fronts are developing & will envelope Greenland & Canadian Arctic Archipelago & appear to pump heat into the High Arctic. These warm fronts continue to suppress  the long term cold front over Canada, to the south. The continuing north Siberian cold front is bordered by higher latitude warm fronts, both in eastern & western Siberia.
//////
Don't worry. I won't post too often, taking away from the better science you posters present. But I wanted you to know that some oppose the AGW deniers in other ways too.   
Title: Re: The 2017/2018 freezing season
Post by: A-Team on November 27, 2017, 08:28:34 PM
Seaice.de, thanks for the link and recommendation. I will take a look at that resource shortly.

However it requires an exceedingly tedious and privacy-invasive registration survey -- your phone and street address etc etc are obligatory -- and at the end the captcha test-text and 'submit' button were both broken; all data even samples was blocked and broken as well. I sent a message to the service desk but that too was a complex, poorly defined form.

Simple but adequate internet forms were perfected 20 years ago, why put up new beta code at this late date? In summary we don't have time to go all over the internet doing this mickey mouse at a hundred different portals; people here will not use the product regardless of merit.

Same thing happened at Copernicus last year with Sentinel: the portal outsourced to aerospace contractor subsidiaries. Finally someone just mirrored all the data up at Amazon so people could get some work done.

Meanwhile, the animation below looks at Fram export since the Sep 10th minimum as well as the Atlantic Waters shelf line. The left half (reversed) shows 78 days from 2016 compared to the same dates from 2017 on the right half. The inset shows UB SMOS thin ice ocean-wide for the same date range. (Their ftp server is slower than a dial-up!)

The sea ice at 100% concentration (according to the 6.25 km UH AMSR2) is shown as pale green with dark green edges to bring out features in Fram export (to the extent there are any) to help visualize floe motion. There's still ambiguity because ice can form de novo, plus aggregate and disperse, within the Fram itself. However export appears to have picked up in November.

Note wipneus regularly reports on export volume on the Piomas forum; a long-range visualization of ice age class export has been posted up-forum numerous times though a fall 2017 update is not currently available.

The issue is apparent persistent cessation of both Beaufort Gyre circulation and Fram export that has accompanied months of mundane weather. It's wait-and-see whether this is a new feature of the New Arctic or just a passing system variability.
Title: Re: The 2017/2018 freezing season
Post by: FishOutofWater on November 27, 2017, 11:47:31 PM
The may be convection going on near the edge of the Chukchi sea shelf edge and Barrow canyon. There has been so much open water in the Beaufort and Chukchi seas this fall that salty Pacific waters may have been flowing into the Arctic through the Bering strait. The fresh water of the Beaufort gyre is being mixed into at the 300 m level. At the 100m level the fresh water lens has moved towards the Mackenzie delta and the main channel of the CAA. Increased amounts of fresh water may have moved through the CAA as export out the Fram declined.

I'm not sure it's happening but this may be the first time since humans have been looking at it that Pacific heat has been advected into the Arctic through the Bering strait. In previous years the heat was all lost to the atmosphere. Heat in the Beaufort and Chukchi was from "summer water" that stored heat as it sank below the icy surface layer in the early fall.

The blocking high over the Aleutians for the past 30 days has been stunningly powerful and has advected huge amounts of atmospheric heat into the Chukchi and Beaufort seas. It also may have increased the flow of Pacific water into the Arctic ocean.
Title: Re: The 2017/2018 freezing season
Post by: FishOutofWater on November 28, 2017, 12:11:41 AM
There's a very strong sea surface height gradient through the Bering sea towards Barrow canyon. this strong SSH gradient is coupled with a strong northwards current. Compare 2016 with 2017 SSH gradients through the Bering strait.
Title: Re: The 2017/2018 freezing season
Post by: Susan Anderson on November 28, 2017, 12:31:27 AM
Fishoutofwater, thank you. That's something I've observed and wondered about this year, as so many big storms have traveled north from the equator this year. Thanks for the clarity.
Title: Re: The 2017/2018 freezing season
Post by: FishOutofWater on November 28, 2017, 01:21:08 AM
Susan, please understand that much of what I wrote is based on interpretation of assimilation model based information on the web. Oceanographers will write research reports on what's happening that you will read about in a year or two. Their reports will be reliable. I'm trained in science but this is not my specialization. Remember that I'm a semi-retired geochemist, not an oceanographer.
Title: Re: The 2017/2018 freezing season
Post by: meddoc on November 28, 2017, 09:18:39 AM
The Vortex seems to have split into 3 Cores, something I haven't seen before.
The Bering still will see a continued Heat Influx, thanks to this rare Configuration.
I wonder if we get to see a Quadruple Core System in this not- so- Freezing Season.
Title: Re: The 2017/2018 freezing season
Post by: A-Team on November 28, 2017, 12:55:09 PM
Very nice, Fish. I had not seen the Mercator Ocean site before. It is an interesting approach to a portal; a lot of neat features there, some of which work a lot better than others. There is no explanation of how products are developed so their accuracy isn't known.

Still, it's great to have the oceanography supplemental to RASM-ESRL. For example the '100m' products (which are actually 92m), provide a nice bathymetry mask for Siberian continental shelf.

The images appear created with Panoply but more likely just use some of the same javascript libraries.. The Geo2D netCDF files are not provided. Access to underlying data png archives is forbidden (interdit) so actually capturing a product involves a lot of manual stepping through screens, though those direct urls can be hacked as explained below allowing ImageJ to import a long png series using 'List to Stack', which creates in effect the unsupported ftp client to their html server.

For the Arctic, MercOcean provides the 18 products below plus a 7 day forecast.  The calendar goes back to 01 Aug 16 but for Arctic surface water temperature anomaly, the return is 'image not generated yet' (désolé, l'image n'a pas encore générée, merci de réessayer plus tard).

The depths are slightly different from those advertised; numbers don't pencil out in meters, feet or fathoms. Perhaps they are still using pre-Revolutionary units of pied du roi, pouce or toise.

To make an animation, start with the link below, make a date range in a spreadsheet, paste on the product type, save as .txt file, sit back and enjoy a croissant and let ImageJ do the rest. This will entirely strip out the site into forum animations in about twenty minutes. (Not the other 17 maps though; the section view called Labrador is also of some interest to us.)

header that receives png types, note double date change needed:
http://static-bulletin.mercator-ocean.fr/img//psy4qv3r1/20171127/arc/psy4qv3r1_20171127_arc_

For everyone's convenience, the attached .txt file provides the links for all 18 from the 10 Sep 17 minimum up until the 27th of November. [work in progress, fixes underway: there's some screw-up at MercOcean involving mis-indexed pngs.] This will generate the same for 2016 with a quick substitution.

sea_surface_height_0m.png
sea_ice_thickness_0m.png
ice_velocity_0m.png
ice_concentration_0m.png
current_0m.png

anom_temperature_0m.png

temperature_0m.png
temperature_34m.png
temperature_92m.png
temperature_318m.png
temperature_1062m.png
temperature_2865m.png

salinity_0m.png
salinity_34m.png
salinity_92m.png
salinity_318m.png
salinity_1062m.png
salinity_2865m.png

http://bulletin.mercator-ocean.fr/en/PSY4#2/62.6/-85.1

Quote
Mercator Ocean is a privately-owned non-profit company. It provides a service of general interest to France and Europe as a whole. The organization was founded and is funded by the five major French institutions involved in operational oceanography: CNRS, Ifremer, IRD, Météo-France and SHOM.
Title: Re: The 2017/2018 freezing season
Post by: A-Team on November 28, 2017, 11:18:21 PM
In support of the analysis Fish is doing above, here are sea temperatures for Nov 2017 at the various depths provided by MercOcean. Oceanography moves a LOT slower than weather but heat content advected from the Bering Sea or Barents/Fram can be massive relative to air and strongly affect both the timing of freeze-over as well as winter thickness development.
Title: Re: The 2017/2018 freezing season
Post by: A-Team on November 28, 2017, 11:33:11 PM
Same as above, but synched into one image to allow easier comparison of activity at the four depths and also shown as reflected depth pairs at regions of special interest such as the Bering Strait and Svalbard/Barents where 0m water temperature (ie at the surface) is compared to that at 32m depth.

The latter region shows subsurface Atlantic Waters having more dramatic changes over the 25 days shown of November 2017; 34m depth is displayed reflected over 0m surface temperatures in the 3rd animation.
Title: Re: The 2017/2018 freezing season
Post by: numerobis on November 29, 2017, 04:37:32 AM
So many storms in South Baffin this year. City services have been suspended ten times already since September.

Each storm brings up a lot of heat with it.

Rain storms heat up the frozen land, and snow storms insulate it. There’s not much sea ice to cover down here.
Title: Re: The 2017/2018 freezing season
Post by: bbr2314 on November 29, 2017, 08:13:06 AM
Hudson Bay's refreeze over the last week has been one of the earliest on record over the past twenty years it seems. Should be mostly frozen by 12/5-12/10!
Title: Re: The 2017/2018 freezing season
Post by: A-Team on November 29, 2017, 03:20:09 PM
Quote
So many storms in South Baffin this year.
Mercator Ocean offers an interesting depth section of water temperature and salinity from Labrador to Greenland. One hopes there is a mooring or two that provides actual data to anchor modeling.

The animation below shows upper salinity over temperature for November, finishing with a forecast out to 08 Dec 17. Salinity at lower depth hardly changes over this timeframe so I dropped the bottom in favor of enforcing synchronicity with the temperature profile time series. The temperature warms markedly with depth even as we go into winter.

Looking at their separate current vs depth map for the North Atlantic, this does not represent a northbound warm water intrusion from a branch of the Gulf stream but rather southbound from the Hudson Bay(?). They show speed ok in color but indicate direction with too-tiny arrows, a common parameter setting omission in Panoply-like tools.

There's a second cross section of interest to us (not analyzed here, called OVIDE CLIVAR 25) that cuts through the AMOC cold spot and Irminger Current below the tip of Greenland. I might write to ask if they can offer sections for the Bering Strait and Fram regions.

I would encourage people to use this site which complements RASM-ESRL. They are likely reprocessing netCDF files stored behind the onerous registration wall of Copernicus which asks that you disable spyware security on your computer to access data files.

http://bulletin.mercator-ocean.fr/en/PSY4#3/72.82/-51.33

Technical note: the very weird implementation of png graphics format is causing a lot of problems for MercOcean. It may have something to do with enabling png animations in html 5 but those are currently quite lame and could be done within gif89. It seems each file is using a different lookup table, probably based on color abundances. Their pngs load as indexed color so unless you immediately convert to RGB, subsequent time series layers will use the LUT of the first image which is wholly inappropriate for them. The horizontal white line in both the temperature and salinity charts is probably a NaN artifact in the underlying data as Panoply-like javascript would not introduce this otherwise.
Title: Re: The 2017/2018 freezing season
Post by: Shared Humanity on November 30, 2017, 05:47:43 AM
Hudson Bay's refreeze over the last week has been one of the earliest on record over the past twenty years it seems. Should be mostly frozen by 12/5-12/10!

It is freezing much faster than 2016 but pretty much in line with 2012 through 2015.
Title: Re: The 2017/2018 freezing season
Post by: SimonF92 on November 30, 2017, 09:47:19 AM
Hello to all,

I generally like to "lurk" on this forum, there are several experts from whom I have learned a great deal over the last few years.

Firstly to the people who take the time to collate data and figures for the rest of us to learn from, I would like to thank you for your continued efforts in doing so.

I generally visit this forum, DMI temps, cci-reanalyser and NSIDC's website at somepoint most days. Today I noticed that cci-reanalyser has updated their service to provide several new visual data sets on the condition of the arctic (and world). Significant new additions are their Snow Depth figures and 500hPA Geopot. Height.

http://cci-reanalyzer.org/wx/DailySummary/#snowd-mslp

Many thanks again

Simon

Title: Re: The 2017/2018 freezing season
Post by: meddoc on November 30, 2017, 10:40:15 AM
The Polar Vortex looks to get tossed around the next few Days, again.
The Result will be a Donut- shaped elongated 2- Core System (Scaninavia & Siberia) spreading over Greenland, CSE- Europe into Siberia & the Far East. Leaving Alaska, the Bering Side exposed.
Title: Re: The 2017/2018 freezing season
Post by: Neven on November 30, 2017, 03:13:23 PM
Today I noticed that cci-reanalyser has updated their service to provide several new visual data sets on the condition of the arctic (and world). Significant new additions are their Snow Depth figures and 500hPA Geopot. Height.

Thanks for that snow depth map, Simon. Very useful.
Title: Re: The 2017/2018 freezing season
Post by: Tor Bejnar on November 30, 2017, 04:15:00 PM
Welcome to the 'published' side of ASIB, Simon!
Title: Re: The 2017/2018 freezing season
Post by: Neven on November 30, 2017, 04:36:52 PM
Ask a Climatologist: Chukchi Sea ice at record low (https://www.alaskapublic.org/2017/11/29/ask-a-climatologist-chukchi-sea-ice-at-record-low/)

Quote
(https://www.alaskapublic.org/wp-content/uploads/2017/11/11292017_Chukchi-600x360.jpg)

The Chukchi Sea should be almost fully covered in sea ice by now. Instead, it’s mostly open water.

Brian Brettschneider, with our Ask a Climatologist segment, says the ice coverage right now in the Chukchi is typical for mid-October, not late-November.
Title: Re: The 2017/2018 freezing season
Post by: A-Team on November 30, 2017, 05:33:13 PM
Here is a sea ice thickness product for 27 Sep to 30 Nov plus 9 day forecast taken from the Mercator Ocean site. They don't indicate its source but it is probably calibrated relative to the SMOS netCDF product at Copernicus described in #378 above. The thickness pattern bears some similarity to RASM-ESRL ice thickness.

It apparently shows frazil ice in the Chukchi that is treated as open water in UH AMSR2 (ie 0 concentration). Export out the Nares Strait is quite effective.

It is more convenient in some ways to view animations at the MercOcean site, for example salinity x depth from May-Nov are linked below though there's no practical way to capture these or rescale (other than full screen mode). They do work well as previews however. The forecast salinity for Dec 9th shows the freshening in the Beaufort Gyre to 318 m depth (but not beyond) as well as the Atlantic Water salt finger wrapping along the Svalbard/Siberian shelf.

MercOcean uses a javascript library called Leaflet which works ok overall but has various limitations and bugs. The server is quite fast. The site may be fairly new as most of the cross sections are not yet available.

http://bulletin.mercator-ocean.fr/en/permalink/PSY4/animation/3/20170501/20171130/2/1
http://bulletin.mercator-ocean.fr/en/permalink/PSY4/animation/3/20170501/20171130/2/2
http://bulletin.mercator-ocean.fr/en/permalink/PSY4/animation/3/20170501/20171130/2/3
http://bulletin.mercator-ocean.fr/en/permalink/PSY4/animation/3/20170501/20171130/2/4
Title: Re: The 2017/2018 freezing season
Post by: A-Team on November 30, 2017, 07:33:47 PM
Quote
Hudson Bay  is freezing much faster than 2016 but pretty much in line with 2012 through 2015.
Right, it's been coldish there relative to way too warm 'everywhere' else (except Siberia).
Title: Re: The 2017/2018 freezing season
Post by: numerobis on November 30, 2017, 11:16:24 PM
Hudson Bay's refreeze over the last week has been one of the earliest on record over the past twenty years it seems. Should be mostly frozen by 12/5-12/10!

Per the ice atlas, that's about normal -- of course we haven't had normal in a while:
Quote
In late October, the ice begins to form along the northwestern shores of the Bay. Some years there may also be a simultaneous development in the cold waters near Foxe Channel. In November, the ice thickens as prevailing winds move it east and southeast. In December the Bay becomes covered with thickening first-year ice.

It's well above normal in Iqaluit through the end of the forecast period, with the lows being warmer than the normal high, and lots of snow.

Reanalyzer shows an angry hot Canadian Arctic. The only exception is the West side of Hudson Bay, which is slightly cooler (and outright cold inland).

I just noticed that the cci-reanalyzer doesn't have a border between NWT and Nunavut. They're up to date on the climate, but not the politics, it seems ;)
Title: Re: The 2017/2018 freezing season
Post by: A-Team on December 01, 2017, 10:30:37 AM
Beaufort Gyre forecast to become re-established in early December, though centered somewhat off to the northwest, along with Fram export. (From Arctic16.gif of NOAA REB plots at ESRL; speeds shown in m/s, direction with arrows.) The Nares cross-post image shows a Fram export from 27 Sept to 30 Nov 2017.

https://forum.arctic-sea-ice.net/index.php/topic,176.msg135241.html#msg135241

(https://forum.arctic-sea-ice.net/index.php?action=dlattach;topic=176.0;attach=55533;image)
Title: Re: The 2017/2018 freezing season
Post by: Neven on December 01, 2017, 02:02:25 PM
Finally some Fram export. It's been a while.
Title: Re: The 2017/2018 freezing season
Post by: Sterks on December 01, 2017, 03:04:03 PM
Beaufort Gyre forecast to become re-established in early December along with Fram export. (From Arctic16.gif of NOAA REB plots at ESRL; speeds shown in m/s, direction with arrows.)

Interesting observation.
Didn't last year (winter) characterize by an almost total lack of Beaufort Gyre due to the train of cyclones coming from the Atlantic, imposing a general cyclonic circulation affecting the ice drift as well?...
In this sense, we may be heading for a more "normal" winter. Once the Chukchi sea freezes, of course.
Title: Re: The 2017/2018 freezing season
Post by: A-Team on December 01, 2017, 03:50:40 PM
It seems the Mercator Ocean ice thickness scheme is quite effective at displaying export (regardless of whether the thickness display is accurate). They offer a daily animation back to 01 Aug 16 that can be viewed (but not saved out at size as it takes 489 gif frames) at the link below, best in full screen mode with the manual arrow setting. Right, export picked up in November 2016 as well.

http://bulletin.mercator-ocean.fr/en/permalink/PSY4/animation/3/20160801/20171130/7/1
Title: Re: The 2017/2018 freezing season
Post by: numerobis on December 01, 2017, 04:49:13 PM
Despite the warmth, Frobisher Bay is freezing up a bit today. There's little blobs of ice out in the bay, with a cap of snow on each.

The winds are calm so it's hard to tell the difference between glassy water or glassy thin ice. But it seems warm for the sea surface to be freezing, and it was snowing last night, so if there's no snow it's probably not ice.

The 5-day forecast is mostly overcast, and forecast lows 5 degrees above the average highs, as it has been for more than a week. There's one clear night in the forecast, but even it isn't expected to get cold.
Title: Re: The 2017/2018 freezing season
Post by: A-Team on December 01, 2017, 08:01:55 PM
Here are the 2017 changes in sea water temperature according to Mercator Ocean, at 34m and 0m depths, from early May when the warm water intrusions start through today when it still persists in both the Bering Strait/Chukchi and Svalbard/SZ region.

The thirty-four meter depth is well within reach of the bottom of the ice provided there is mixing from waves and other mechanisms. MercOcean also offers four deeper layers; while these are interesting, little visible change occurred over this time frame.

Climate change modeling traditionally prioritizes equatorial meteorology, with Arctic ice and its oceanography nominally coupled in but largely belittled (along with Arctic methane). More recently though, influxes of Bering Sea and Atlantic Waters are coming to be seen as important drivers of ice trends, with weather primarily contributing seasonal variability, ice pack motion and moisture intrusions.

Water has vastly greater heat capacity and heat conductivity than air and, given some mixing of stratification, has adequate potential to melt off Arctic ice, in effect permanently because of thermal inertia. This is also being argued for interfaces with ice shelves and tidewater glaciers in both Greenland and Antarctica.

Given the drastic factual revisions that came about this fall from OMG (Oceans Melting Greenland), I do have to wonder about the value of previous 'coupled' model predictions for Greenland's contributions to sea level rise  -- complete nonsense all along but possibly a lingering source of misinformation and complacency for policy makers.  https://tinyurl.com/yc4uvszc
Title: Re: The 2017/2018 freezing season
Post by: bbr2314 on December 01, 2017, 09:20:06 PM
Hudson Bay's refreeze over the last week has been one of the earliest on record over the past twenty years it seems. Should be mostly frozen by 12/5-12/10!

Per the ice atlas, that's about normal -- of course we haven't had normal in a while:
Quote
In late October, the ice begins to form along the northwestern shores of the Bay. Some years there may also be a simultaneous development in the cold waters near Foxe Channel. In November, the ice thickens as prevailing winds move it east and southeast. In December the Bay becomes covered with thickening first-year ice.

It's well above normal in Iqaluit through the end of the forecast period, with the lows being warmer than the normal high, and lots of snow.

Reanalyzer shows an angry hot Canadian Arctic. The only exception is the West side of Hudson Bay, which is slightly cooler (and outright cold inland).

I just noticed that the cci-reanalyzer doesn't have a border between NWT and Nunavut. They're up to date on the climate, but not the politics, it seems ;)

Actually, I believe Hudson Bay is one of the only peripheral regions that has *not* experienced a catastrophic delay in the onset of freezing in recent years -- things have remained fairly steady, and its endurance has also been about constant.

With increased heat flux in autumn, it might be worth considering differentiating between ice regions that were always multi-yr vs. first year. Obviously large swaths of the Arctic are now transitioning, but outside of Foxe Basin, Hudson Bay has always been entirely FYI (to my knowledge).

The impact of the additional summertime heat could be for more convective autumnal weather which has a net impact of allowing earlier refreeze, as the dissipation of accumulated heat occurs faster thanks to the massive LPs that have been forming. This does nothing to alleviate the burden on the multi-yr ice (in fact, destroying it through winds + waves), but it does allow FYI to form faster when temperatures get sufficiently cold enough. In the case of HB this year, the refreeze has been more rapid than normal in terms of its onset to where it is now (check out the last week on EOSDIS!).

This would also help explain why the Sea of Okhotsk has also seen record numbers in recent yrs. It is not each and every year of course, but these distinctions are worth considering.

What happens if at some point we end up with MYI in Okhotsk + HB and only FYI in the CAB?
Title: Re: The 2017/2018 freezing season
Post by: A-Team on December 02, 2017, 03:18:05 PM
Here is a closer look at thickness and velocity of Fram export this fall. The last frame shows velocities (Greenland inset) increasing from 0.3 m/s up to 0.8 m/s (which is 70 km/day) in the south; these have only picked up since November The distance scale is given by separation of the two latitudes, 555 km. Note the forecast represent a ten-day jump from the reanalysis series.

The ice being exported now is up to 1.75m thick. Various other ice thickness resources are available: RASM-ESRL, Piomas, SMOS, Cryosat and so on. It's unclear how accurate any of them are on absolute thickness in the Fram and whether they are truly independent or all rely on the same satellites for their daily reset. However the resurgence of export per se could be verified by floe motion as seen in Sentinel satellites. Wipneus provides a regular estimate of daily export volume which should be available for November soon.

The overall motion resembles that of a viscous liquid (poorly mixed paints) that is being squeezed out (like toothpaste) through Svalbard and NE Greenland from bulk motion of the ice pack which in the later frames is that of a classical Beaufort Gyre coupled with the central Transarctic Drift. Once past the Nord station peninsula, the ice gets caught up in an accelerating southbound Greenland Current and never rejoins the main ice pack.

Technical note: The RASM-ESRL provides a smoother forecast than MercOcean which discards intermediate days. The version below uses a continuous ColorBrewer palette posterized later in Gimp with an inset whole ocean that is easily made in Panoply by resetting 'visible radius' and plot size. Posterization is a form of contouring that makes feature tracking more certain. However RASM-ESRL's mapping domain does not extend far enough south to pick up enough of the export train. Its forecast suggests coming export will be from Svarlbard-marginal ice rather than thicker CAA-marginal.

http://bulletin.mercator-ocean.fr/en/permalink/PSY4/animation/3/20170927/20171130/5/1 MO velocity animation
Title: Re: The 2017/2018 freezing season
Post by: numerobis on December 02, 2017, 11:23:14 PM
Quote
Despite the warmth, Frobisher Bay is freezing up a bit today. There's little blobs of ice out in the bay, with a cap of snow on each.

Well that went quickly.

Yesterday:
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fice-glaces.ec.gc.ca%2Fprods%2FWIS33CT%2F20171201180000_WIS33CT_0009762830.gif&hash=17af1b1319388f6a6ceea55b9d7f4b17)

Today:
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fice-glaces.ec.gc.ca%2Fprods%2FWIS33CT%2F20171202180000_WIS33CT_0009764381.gif&hash=0fb9e4a424ce1f42cdeb24f7f932376a)

What happens if at some point we end up with MYI in Okhotsk + HB and only FYI in the CAB?

How would you get MYI in Hudson Bay? Temperatures are higher than historical, and historically there was none.
Title: Re: The 2017/2018 freezing season
Post by: bbr2314 on December 03, 2017, 01:14:47 AM
Quote
Despite the warmth, Frobisher Bay is freezing up a bit today. There's little blobs of ice out in the bay, with a cap of snow on each.

Well that went quickly.

Yesterday:
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fice-glaces.ec.gc.ca%2Fprods%2FWIS33CT%2F20171201180000_WIS33CT_0009762830.gif&hash=17af1b1319388f6a6ceea55b9d7f4b17)

Today:
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fice-glaces.ec.gc.ca%2Fprods%2FWIS33CT%2F20171202180000_WIS33CT_0009764381.gif&hash=0fb9e4a424ce1f42cdeb24f7f932376a)

What happens if at some point we end up with MYI in Okhotsk + HB and only FYI in the CAB?

How would you get MYI in Hudson Bay? Temperatures are higher than historical, and historically there was none.

You would need a cooler repeat of summer 2017, where snow is retained along much of the shoreline til the end of June or July. If we see the current snowfall feedback make much more progress, this will not be unfeasible (explaining why 2017 was so anomalously snowy).

Even though extent has gone into lag mode, volume continues to perform phenomenally and historically well:

(https://ccin.ca/home/sites/default/files/snow/snow_tracker/plot_anom_sdep.png)

(https://ccin.ca/home/sites/default/files/snow/snow_tracker/na_swe.png)

Hudson Bay SSTs are largely a function of whether the surrounding land mass is snow covered. When it is, ice forms and it becomes a source for cold air. When it isn't, the ice is unprotected and mostly melts out (exception being parts of Foxe Basin).

If Hudson Bay begins behaving more like Foxe Basin -- which is much more protected, but also only a hair to the north -- it is not unfeasible for MYI to begin accumulating in the most protected parts. Historically, this must have occurred, the question is, how marginal were the conditions, and does our worsening open water/moisture flux conundrum make it more likely?
Title: Re: The 2017/2018 freezing season
Post by: Ice Shieldz on December 03, 2017, 10:16:07 AM
Below see precipitable water for the months of October & November averaged from 65°N–90°N. 2017 also came in second from 80°N–90°N but it was closer to the rest of pack.
Title: Re: The 2017/2018 freezing season
Post by: Niall Dollard on December 03, 2017, 12:50:04 PM
Ask a Climatologist: Chukchi Sea ice at record low (https://www.alaskapublic.org/2017/11/29/ask-a-climatologist-chukchi-sea-ice-at-record-low/)

Quote
(https://www.alaskapublic.org/wp-content/uploads/2017/11/11292017_Chukchi-600x360.jpg)

The Chukchi Sea should be almost fully covered in sea ice by now. Instead, it’s mostly open water.

Brian Brettschneider, with our Ask a Climatologist segment, says the ice coverage right now in the Chukchi is typical for mid-October, not late-November.

Not really any surprise then that November 2017 was record mildest at  Utqiaġvik/Barrow.

Edit : Credit to Rick Thoman
Title: Re: The 2017/2018 freezing season
Post by: A-Team on December 03, 2017, 12:54:49 PM
Here are the sea surface heights along with salinity and currents for November and early December with emphasis on the Beaufort, Chukchi and Bering Strait regions according to Mercator Ocean.

Technical note: Mercator Ocean puts out two forecasts: for today and for 9 days out. These are stored in a special directory that contains a /9/ in its url. So far so good, but then tomorrow they will overwrite today's forecast with re-analysis and so on, in effect deleting all forecasts over time even though they maintain a separate duplicate directory for re-analysis only!

In other words, to see how MercOcean is doing with forecast skill, it is necessary to save out the 9-day for each of their 18 products and wait nine days so they can be compared with hindcast (~observation). Of course we have no real idea how accurate this thickness product or any other really is this late in the year.


The 9-day ice thickness forecast is archived below. It is not actually saying the Chukchi will be frozen over, only that the ice there will be less than 0.45 m thick (left triangle extension on scale bar). This would appear to be human error in scale configuration because accurate 0.0m to 0.5m thickness is a speciality of readily available SMOS products.
Title: Re: The 2017/2018 freezing season
Post by: Hyperion on December 03, 2017, 08:53:51 PM
Quote
What happens if at some point we end up with MYI in Okhotsk + HB and only FYI in the CAB?

How would you get MYI in Hudson Bay? Temperatures are higher than historical, and historically there was none.

You would need a cooler repeat of summer 2017, where snow is retained along much of the shoreline til the end of June or July. If we see the current snowfall feedback make much more progress, this will not be unfeasible (explaining why 2017 was so anomalously snowy).

Even though extent has gone into lag mode, volume continues to perform phenomenally and historically well:

Well it may not technically be "historically" but its starting to look like the arctic ocean may well have de-iced and Greenland succumbed to a runaway collapse scenario of marine ice sheet cliff instability in the last 13ka. Its now being admitted that this happened in west Antarctica about 10000 BC, with the cliff fragment keel gouges they've found on the sea floor. This would explain all those ancient maps of Antarctica, and fresh mammoth remains in the new Siberian islands etc.

So if Greenland goes into a runaway structural failure of ice cliffs getting higher and higher as they  crumble (100m above the waterline is the limit for ice structurally apparently). Compounded by warm salty water rotting out the legs of the ice sheet, so allowing periodic large block slump events to flush out the bergs. Then the nth Atlantic could flood with giant bergs, turning over the gulfstream south of Newfoundland, and a full Warm Arctic, Cold Continent event could occur until (and if) the stored thermal energy in the arctic oceans upper km or so can dissipate.

I guess that multiyear ice in Hudson and Okhotsk while the Arctic is blue year round would not look so strange in such a "Final Dryas" event
Title: Re: The 2017/2018 freezing season
Post by: Neven on December 03, 2017, 10:21:59 PM
Here are November surface air temperature graphs for the Arctic as a whole, and for the four sides of the Arctic (the map shows distribution):
Title: Re: The 2017/2018 freezing season
Post by: Tor Bejnar on December 04, 2017, 02:50:00 AM
Four equal quadrants, I see. (Forgive me if you don't see them as being equal: I'm not wearing my glasses at the moment, and it might be relevant that I am an American.)
 :D :-\ ::)
Title: Re: The 2017/2018 freezing season
Post by: Neven on December 04, 2017, 11:00:08 AM
Four equal quadrants, I see. (Forgive me if you don't see them as being equal: I'm not wearing my glasses at the moment, and it might be relevant that I am an American.)
 :D :-\ ::)

The American quadrant is the biggest!

Hmm, maybe I should make them equal in size, but I'm not sure how that looks geographically (especially Pacific)...
Title: Re: The 2017/2018 freezing season
Post by: A-Team on December 04, 2017, 05:04:41 PM
Nice summary of extreme warmth for the Alaskan Arctic coast today by Bob Henson [edit: by Christopher Burt]:

Quote
November 2017 averaged 17.2°F in Utqiaġvik (Barrow), Alaska, a new monthly record—besting the previous record of 15.3°F established in November 1950—and some 16.4° above average. This was also the second month of the year with a record-high average temperature, the other being this past July with a 46.0°F monthly average (the fourth highest reading observed in any month on record).

Winters in Utqiaġvik have seen a dramatic warming over the past 10 years, as Figure 1 below illustrates. In fact, it has not just been the winters. As of November 30, the average in Utqiagvik for 2017 stands at 19.5°. That value will surely drop once the upcoming cold of December is factored in, but if December temperatures are near or above average, then 2017 will still end up as the second warmest year on record in Utqiaġvik, behind only 2016 (which averaged 18.9°F). As long as this year ranks in the top eight, as seems very likely, then eight of the warmest years on record for Utqiaġvik will have occurred in just the past 10 years....[lots more]
https://www.wunderground.com/cat6/amazing-autumn-alaskas-north-slope-record-warmth-record-low-sea-ice-extent
Title: Re: The 2017/2018 freezing season
Post by: Sterks on December 04, 2017, 05:51:03 PM
Four equal quadrants, I see. (Forgive me if you don't see them as being equal: I'm not wearing my glasses at the moment, and it might be relevant that I am an American.)
 :D :-\ ::)

The American quadrant is the biggest!

Hmm, maybe I should make them equal in size, but I'm not sure how that looks geographically (especially Pacific)...
Why not making the Pacific region larger, even if it overlaps other regions. When I think on the Pacific side (and I believe many people here too) I think on a much broader region including most of the Beaufort sea, reaching Amundsen Gulf on one side, and taking on the other side part of the ESS as well (almost reaching the New Siberian Islands).
In other words 120W to 150E,
clockwise
around the pole
north pole
Title: Re: The 2017/2018 freezing season
Post by: bhenson on December 04, 2017, 05:53:01 PM
Thanks for the hat tip, A-Team!  Credit for the article actually goes to ace weather historian Christopher Burt (author of "Extreme Weather"), working closely with Rick Thoman, NOAA/NWS Alaska Region.

--Bob

Nice summary of extreme warmth for the Alaskan Arctic coast today by Bob Henson:

Quote
November 2017 averaged 17.2°F in Utqiaġvik (Barrow), Alaska, a new monthly record—besting the previous record of 15.3°F established in November 1950—and some 16.4° above average. This was also the second month of the year with a record-high average temperature, the other being this past July with a 46.0°F monthly average (the fourth highest reading observed in any month on record).

Winters in Utqiaġvik have seen a dramatic warming over the past 10 years, as Figure 1 below illustrates. In fact, it has not just been the winters. As of November 30, the average in Utqiagvik for 2017 stands at 19.5°. That value will surely drop once the upcoming cold of December is factored in, but if December temperatures are near or above average, then 2017 will still end up as the second warmest year on record in Utqiaġvik, behind only 2016 (which averaged 18.9°F). As long as this year ranks in the top eight, as seems very likely, then eight of the warmest years on record for Utqiaġvik will have occurred in just the past 10 years....[lots more]
https://www.wunderground.com/cat6/amazing-autumn-alaskas-north-slope-record-warmth-record-low-sea-ice-extent
Title: Re: The 2017/2018 freezing season
Post by: numerobis on December 04, 2017, 05:56:03 PM
Last post, written Saturday, I said Frobisher Bay had *finally* frozen over.

This morning I wake up to blue water on the bay. A weak storm blew in, with mild temperatures. Currently -2 C at the airport. There was a forecast risk of freezing rain, but that appears to be gone in the most recent forecast.

Granted, this is a highly variable time of the year. The normal high is -15, while the record highs are above freezing. Still, we're on our second or third week of consistently well-above-average temperatures.

Had the ice lasted, it would have been covered by quite a lot of snow. It was beautiful light fluffy powder on the trails yesterday; that'll have been blown down to the low points -- such as the bay (I can see a lot more rock out there).
Title: Re: The 2017/2018 freezing season
Post by: 2phil4u on December 04, 2017, 09:15:22 PM
My question never be answered in a german forum, maybe the question is to complicated, because there are so many factors.
Lets take a scenario.
Lets take the same condition, that occur 20 years agon.
Now  lets replace the arctic ocean water with a fluid with a much lower freezing point.
I have to do this to look for the effect of  ic in the energy flux.
So we have the case, that after low ice minima, ice is growing.
So it seems (at  least on the surface) that the extra energy is lost due to later refreezing, lower insulation etc pp.
Now the question.
What would be the temperature of the arctic ocean say for the nieveau of 1980, if the freezing point of water would be 20 degree lower.
This question is intersting.
Would the ocean be much warmer, no, if so, there would be a massive positive feedback and ice would dissapear faster and faster.
But also this feedback is different at different north, at n80 it may be the case, that ice was warming over the year, but at n 70 it was cooling.
Every discussion is difficult, because arguments of higher temperatures and higher ohc are named, but of course this is the case is arctic is flued with warmer air and the temperatures are higher in general.
The question is more like if there is a decent negative feedback, so that open water or a higher energy input in the arctic at least at n80 has a higher radiaton in winter then the less albedo can compensate.
The only option would be  something like a quicker cooling surface, that outperform the more heat due to summer, but deeper water is warming, so that ohc is still rising.
I dont know, what happens if water gets like an extra heat in summer. After refreeze is the Temperature delta bigger, so that deeper water is warming or is it like.
Ice got later and growth is slower, that also means there is more heat goint to space and also deeper water could adjust.
I dont know.
Title: Re: The 2017/2018 freezing season
Post by: magnamentis on December 04, 2017, 10:05:00 PM
My question never be answered in a german forum, maybe the question is to complicated, because there are so many factors.
Lets take a scenario.
Lets take the same condition, that occur 20 years agon.
Now  lets replace the arctic ocean water with a fluid with a much lower freezing point.
I have to do this to look for the effect of  ic in the energy flux.
So we have the case, that after low ice minima, ice is growing.
So it seems (at  least on the surface) that the extra energy is lost due to later refreezing, lower insulation etc pp.
Now the question.
What would be the temperature of the arctic ocean say for the nieveau of 1980, if the freezing point of water would be 20 degree lower.
This question is intersting.
Would the ocean be much warmer, no, if so, there would be a massive positive feedback and ice would dissapear faster and faster.
But also this feedback is different at different north, at n80 it may be the case, that ice was warming over the year, but at n 70 it was cooling.
Every discussion is difficult, because arguments of higher temperatures and higher ohc are named, but of course this is the case is arctic is flued with warmer air and the temperatures are higher in general.
The question is more like if there is a decent negative feedback, so that open water or a higher energy input in the arctic at least at n80 has a higher radiaton in winter then the less albedo can compensate.
The only option would be  something like a quicker cooling surface, that outperform the more heat due to summer, but deeper water is warming, so that ohc is still rising.
I dont know, what happens if water gets like an extra heat in summer. After refreeze is the Temperature delta bigger, so that deeper water is warming or is it like.
Ice got later and growth is slower, that also means there is more heat goint to space and also deeper water could adjust.
I dont know.

while i'm not able to answer your question i thought to add the idea that even if all surplus heat will be lost to space, which i don't believe because some of the heat is stored at depth, the later re-freeze will result in thinner ice (less time to build ) and in the process we shall have earlier breakup/melt under same conditions while we had bad melting conditions recently so that the described feedback was somehow not showing. sorry if that's not relevant but it came to my mind while reading your post.
Title: Re: The 2017/2018 freezing season
Post by: Neven on December 04, 2017, 10:54:14 PM
My question never be answered in a german forum, maybe the question is to complicated, because there are so many factors.

It's an interesting question, but if the answer is so complicated that a lot of people share their thoughts, the thread will go heavily off-topic. So maybe ask somewhere else, or open a new thread. Unless someone has a quick answer, but I doubt it.  :)
Title: Re: The 2017/2018 freezing season
Post by: A-Team on December 05, 2017, 12:31:11 AM
Quote
credit for Alaskan historic data goes to C Burt and R Thoman
Duly noted and welcome aboard, Bob!

We're hoping you can explain what's going on with the late freeze of the Chukchi this fall -- is it warm air advected from the south, a La Nina effect that will continue, a one-off intrusion of Bering Sea water, a persistent water vapor/cloud local greenhouse effect, a hangover from last year's thin ice, wind or Ekman mixing up of surface water, just continuing trend with adverse natural variability, or all of the above in some hopelessly complex inter-coupled way?

In any event, the Chukchi has crossed the 'seasonally open' threshold, having been open for nearly 8 months this year. It's missed 3 months of the freezing season in terms of ice thickening. While it's only a piece of the larger Arctic Ocean, it seems the latter's future is eroding via its two portals and along its eastern Siberian periphery.

The first graphic below compares Dec 2nd of 2017 with 2013-2016. The open water ratios to 2013 baseline (pixel counts from UH AMSR2 3.125 km which include some Bering Sea) suggest the 2017 lag in freeze-up is becoming most unusual with no end in sight (per MercOcean or RASM-ESRL ten day forecasts, not shown).

The second graphic compares 2017 to 2016 from the 10 Sep minimum to 03 Dec. The lower images show daily differences which sometimes help visualize pauses and even retreats in ice coverage. Sea ice at 100% concentration is shown in pale green.

Note: all my animations are public domain with permission granted to reproduce if credited with link to Neven's sea ice forum.
Title: Re: The 2017/2018 freezing season
Post by: Shared Humanity on December 05, 2017, 02:45:38 AM
That is one scary chart with the inflection point in the 1990's. Clearly something has changed and the change appears to be persistent, if not permanent.
Title: Re: The 2017/2018 freezing season
Post by: A-Team on December 05, 2017, 11:48:54 AM
Quote
one scary chart
Presumably an objective rationale for picking the breakpoint in the two linear regressions?

The animation below shows the Chukchi forecast in terms of concentration (top) and thickness (reflected) out to 14 Dec 17. It is closing in but still not frozen over. The RASM-ESRL forecast area does not extend into the Bering Sea.

The inset shows 2012 from 01-15 Jan 13 when UH AMSR2 archive next becomes available. Open water, shown in yellow, persisted into January that year. In fact it's hard to tell whether the dates are in order or running backwards.

We have not focused too much here on decline of sea ice in the Bering and Barents seas as it seems a 'given' that the ice there will be farther along in retreat trends than the more northern Arctic Ocean. However that's not the case for the Bering Sea according to a time series going back to 1850.

A database for depicting Arctic sea ice variations back to 1850
JE Walsh et al
http://onlinelibrary.wiley.com/doi/10.1111/j.1931-0846.2016.12195.x/full open source
http://www.beringclimate.noaa.gov/essays_mcnutt.html Bering Sea overview

Quote
Arctic sea ice data from a variety of historical sources have been synthesized into a database extending back to 1850 with monthly time-resolution. The synthesis procedure includes interpolation to a uniform grid and an analog-based estimation of ice concentrations in areas of no data. The consolidated database shows that there is no precedent as far back as 1850 for the 21st century's minimum ice extent of sea ice on the pan-Arctic scale. A regional-scale exception to this statement is the Bering Sea. The rate of retreat since the 1990s is also unprecedented and especially large in the Beaufort and Chukchi Seas. Decadal and multidecadal variations have occurred in some regions, but their magnitudes are smaller than that of the recent ice loss. Interannual variability is prominent in all regions and will pose a challenge to sea ice prediction efforts.
Title: Re: The 2017/2018 freezing season
Post by: snrjon on December 05, 2017, 01:00:02 PM
That is one scary chart with the inflection point in the 1990's. Clearly something has changed and the change appears to be persistent, if not permanent.

Hi there, I'm a newbie in posting, though lurking and trying to learn for some time. I find the information on this forum fascinating, and I think the graphics provide quite outstanding postings!

I was interested though to see the Barrow temp history brought up as an example of climate change. AFAIK Barrow is well characterised in the literature (Hinkel et al 2003) as a winter urban heat island, with a population that has grown from 300 mainly subsistence inhabitants to over 4000 "western lifestyle" over the length of the record.

[url]http://onlinelibrary.wiley.com/doi/10.1002/joc.971/abstract/[url]

Undoubtedly the ice extent in early winter in the Chukchi has significantly reduced in recent years, but is the Barrow temperature record change caused by development rather than mirroring the sea ice pattern?

If the Hinkel et al 2003 study has been superseded I would be interested to hear about it.
Title: Re: The 2017/2018 freezing season
Post by: Niall Dollard on December 05, 2017, 04:14:08 PM
The Bering Sea Ice is a bit of an oddity. Probably very storm related. Some interesting comments here from the NWS Anchorage (http://tgftp.nws.noaa.gov/data/raw/fz/fzak30.pafc.ico.afc.txt), Sea Ice outlook at the end of November:

LOOKING AT THE BIG PICTURE...THE CHUKCHI SEA REMAINS MOSTLY OPEN
SOUTH OF ROUGHLY 74N WITH SEA SURFACE TEMPERATURES REMAINING ABOVE
FREEZING THROUGHOUT MUCH OF THE SEA ICE FREE WATER. IN THE BERING
SEA...SEA ICE HAS STRUGGLED TO BECOME ESTABLISHED BEYOND THE SHALLOW
AND PROTECTED WATERS ALONG THE WEST COAST OF ALASKA AS STORMS HAVE
BROUGHT PERIODS OF WARMER AIR TO THE REGION IN OCTOBER AND NOVEMBER.

AS WE LOOK FORWARD THROUGH FEBRUARY...THE CHUKCHI SEA IS EXPECTED TO
EXPERIENCE SEA ICE CONDITIONS SIMILAR TO LAST WINTER WITH THE ICE
PACK SLOW TO FORM AND REMAINING RELATIVELY MOBILE THROUGH MUCH OF
THE WINTER. THE BERING SEA ICE PACK MAY ALSO BE SLOW TO ESTABLISH IF
STORMS AGAIN HAVE A PATH THROUGH THE BERING SEA INTO EARLY 2018 AS
EXPECTED. HOW FAR NORTH THESE STORMS TRACK WILL HAVE A LARGE IMPACT
ON THE QUALITY OF THE ICE PACK WITHIN THE BERING SEA LATER THIS
WINTER.

AT THIS TIME...THERE IS A 50 PERCENT CHANCE THAT SEA ICE WILL REACH
SAINT PAUL ISLAND SOMETIME THIS SEASON. IF IT DOES...IT LIKELY WOULD
NOT OCCUR BEFORE THE END OF FEBRUARY. THERE IS A 30 PERCENT CHANCE
THAT SEA ICE WILL REACH SAINT GEORGE ISLAND THIS SEASON. IF IT
DOES...IT LIKELY WOULD NOT OCCUR BEFORE THE END OF FEBRUARY.
Title: Re: The 2017/2018 freezing season
Post by: Niall Dollard on December 05, 2017, 04:39:41 PM
I see the record November mean temperature at Utqiaġvik as a product of a long chain of events, with many occurring simultaneously. Something along the lines of :

1. Man increases greenhouse gases. Increase in temperatures.
2. Leading to increased global water vapour
3. Leading to increased global temperatures
4. Especially in the Arctic (Amplification)
5. Multiyear ice decreases each year.
6. By 2016, very little MYI left in the Beaufort/Chukchi. Even "big block" could not survive. Without MYI, Beaufort/Chukchi much easier to melt out.
7. At the same time a strong El Nino is in full swing.
8. Leading to warmer air heading north and warmer Pacific SSTs through the Bering.
9. By Sept 2017 Ice north of the Chukchi has melted back well into the Arctic Basin allowing Pen Hadow to sail as far as 81 North.
10. All this vast (unprecendented) extent of ocean, north, west and south west of Utqiaġvik takes a long time to re-freeze.
11. Coupled with the high SSTs and a synoptic weather pattern advecting warm air up through the Bering Strait though much of the fall. Aleutian Low replaced by Aleutian High.
12. Leading to record mean temp.   
Title: Re: The 2017/2018 freezing season
Post by: Neven on December 05, 2017, 05:22:06 PM
Why not making the Pacific region larger, even if it overlaps other regions. When I think on the Pacific side (and I believe many people here too) I think on a much broader region including most of the Beaufort sea, reaching Amundsen Gulf on one side, and taking on the other side part of the ESS as well (almost reaching the New Siberian Islands).
In other words 120W to 150E,
clockwise
around the pole
north pole

Thanks for the suggestion, Sterks. I'll give it some thought.
Title: Re: The 2017/2018 freezing season
Post by: Neven on December 05, 2017, 10:09:52 PM
Thanks for the suggestion, Sterks. I'll give it some thought.

I have given it some thought, and to make my fellow OCD neurotics happy, I've divided the Arctic up into four equal quadrants. The Pacific quadrant doesn't look too great geographically, gobbling up parts of Siberia and Canada, but it's not my fault that they made Bering Strait as narrow as it is. And besides, the quadrant does follow sea borders better now (consisting of Beaufort, Chukchi and ESS).

And to punish Tor for his unwarranted irony, I've renamed the American quadrant to Canadian quadrant. Canada first.  ;)

Title: Re: The 2017/2018 freezing season
Post by: A-Team on December 05, 2017, 10:51:11 PM
Quote
is there any way to make our dorky flat graphs come to life?
ESRL has quite a few items we have not made use of so far, notably the 'meteograms'  and 'xsections' in the archive of 'Reb Plots'. These are mostly for selected weather stations around the western Arctic, with the exception of one which seems to average the whole Arctic Ocean but over current sea ice only. (These are ten day predictions but include the initial state.)

These meteograms provide W/m2 of radiative transfer, ice volume, ice area, air pressure, temperature and precip/6hrs. The display is weirdly fascinating despite some layout erratics at ESRL's end.

ArcticOcean_meteogram below
Tiksi_meteogram
OliktokPoint_meteogram
Eureka_meteogram
BeringStraits_meteogram
Beaufort_xsection
Beaufort_meteogram
Barrow_meteogram
Alert_meteogram

Technical note: It's somewhat a nuisance to animate these because of how they're archived, ie the whole bundle of files for each day of the time span has to be downloaded and the specific file fished out, below ArcticOcean_meteogram. Scraping off white space, these are 550x991 pixels, too much for the forum with 78 frames. Reducing to 700 pixels height and underlaying two dimmed copies of UH AMSR2 for the day in question results in the animation below.

https://www.esrl.noaa.gov/psd/forecasts/seaice/
Title: Re: The 2017/2018 freezing season
Post by: Daniel B. on December 06, 2017, 06:06:54 PM
Nice Neven.  Do you have longer range data for the quadrants?  Based on your graphs, the temperature shows an increase due to the 2016 El Nino (except for Siberia).  It would be relatively flat otherwise.  Perhaps a longer timeframe would be able to confirm these results.
Title: Re: The 2017/2018 freezing season
Post by: Tor Bejnar on December 06, 2017, 06:39:09 PM
The actually equal-in-size quadrants makes some sense when comparing regions.  I feel appropriately put in my place  :'( only because I thought the irony was warranted.  ;)

Almost on-topic (that is, freezing season) the local (Tallahassee, Florida) forecast calls for lows of 33ºF this weekend.  I need to bring my orchids inside early this year.
Title: Re: The 2017/2018 freezing season
Post by: Neven on December 07, 2017, 12:53:33 AM
Nice Neven.  Do you have longer range data for the quadrants?  Based on your graphs, the temperature shows an increase due to the 2016 El Nino (except for Siberia).  It would be relatively flat otherwise.  Perhaps a longer timeframe would be able to confirm these results.

Here's the entire dataset with linear trend lines:
Title: Re: The 2017/2018 freezing season
Post by: Neven on December 07, 2017, 12:59:34 AM
The actually equal-in-size quadrants makes some sense when comparing regions.

Technically I'm not comparing regions, but monthly temperatures for the past 10/70 years within those individual regions. It's like a graph showing temperatures for the past 50 years in Paris, London, New York and Nuuk, allowing a quicker overview than when making four separate graphs.

But I didn't like the distribution along geographical lines. That map just didn't look right, and so I re-did it. Again, I wish Bering Strait was as wide as the Atlantic on the other side.  ;D

Quote
I feel appropriately put in my place  :'( only because I thought the irony was warranted.  ;)

It was indeed warranted, but I'm not changing it back to 'American'.  :P ;)
Title: Re: The 2017/2018 freezing season
Post by: Jim Hunt on December 08, 2017, 09:01:04 AM
Some festive illuminations from Santa and Snow White:

http://GreatWhiteCon.info/2017/12/the-festive-season-in-the-arctic/

Rudolf et al. are currently taking a refreshing dip in the Chukchi Sea:
Title: Re: The 2017/2018 freezing season
Post by: Thomas Barlow on December 08, 2017, 06:19:41 PM
Just when you thought it was safe to go outdoors again:
Title: Re: The 2017/2018 freezing season
Post by: Tealight on December 11, 2017, 12:13:24 AM
I finally had some time again playing around with sea ice concentration data.

My first project was creating maps showing the number of ice free days in a given year, ranging from 0-180 days. Above 180 days the region can be considered seasonally ice-covered and not seasonally ice-free (technically 183 days, but it's not a great number to put on the the legend)

Other recent years can be found here(Antarctic too):
https://sites.google.com/site/cryospherecomputing/analysis/ice-free-days

(https://drive.google.com/uc?id=0B1HTR0ONiUmENWp0bU9LZnB6bTg&export=download)

The second project calculated the earliest, median and latest ice free date for the melting & freezing season for each grid cell using the 15% concentration threshold. I chose median instead of mean (average) because if one years doesn't get ice free at all it's impossible to calculate a mean.

It's a shame that I can't make the maps interactive to show the exact date with mouse over. From the color scale you can only estimate the rough date. Every tick on the legend shows the beginning of the month and not the middle.

See first attachment for the Arctic median freeze date. Other maps under the link:
https://sites.google.com/site/cryospherecomputing/analysis/melt-freeze-dates

The third project is a composite map showing which year has the lowest SIC and which one has the highest SIC. Again an interactive map would have been better, but this time there are only 11 different years and it's easier to distinguish them. I coded them to update every day on my webpage.

See second attachment for the 9th December. The updated maps are under the link:
https://sites.google.com/site/cryospherecomputing/analysis

Sometimes the maps look like someone has set off several paint bombs. For this reason I also created maps showing the earliest ice-free year for each grid cell (below 15% SIC). They are a lot cleaner.

One grid cell example: If the year 2010 had a SIC less than 15% and every year before had more than 15% then the cell would get the value 2010. It doesn't matter if 2011,2012,2013,... all have been ice-free too. Only when 10 out of the 11 considered years are ice-free the grid cell will be empty.

See third attachment for the earliest ice-free year
Title: Re: The 2017/2018 freezing season
Post by: Jim Hunt on December 11, 2017, 09:46:35 AM
A new video from Kevin Pluck:

http://youtu.be/y2LOHNIjQMg

If you watch and wait for bit sea ice appears on the scene.
Title: Re: The 2017/2018 freezing season
Post by: oren on December 11, 2017, 09:55:39 AM
I finally had some time again playing around with sea ice concentration data.
Thanks, very interesting stuff.
BTW, the Chukchi is where all the action is happening recently, maybe you can get some graph or map focusing on the Chukchi and showing the lengthening of the ice-free period.
Title: Re: The 2017/2018 freezing season
Post by: Jim Hunt on December 11, 2017, 10:07:48 AM
BTW, the Chukchi is where all the action is happening recently, maybe you can get some graph or map focusing on the Chukchi and showing the lengthening of the ice-free period.

Like this for example?

http://GreatWhiteCon.info/2017/12/the-festive-season-in-the-arctic/#Dec-10
Title: Re: The 2017/2018 freezing season
Post by: numerobis on December 11, 2017, 04:51:46 PM
Fog all over Frobisher Bay today under clear skies. It's the first day of normal temperatures in about a month. We have a few days in a row scheduled like this, so the bay should finally freeze up and stay frozen.

It's nice to see the sun again, too.

PS: wrote the words above in the morning, at sunrise. Now it's 1pm and the freezing-over is almost complete. There's still some wisps of fog over the remaining bits of open water.
Title: Re: The 2017/2018 freezing season
Post by: mustangchef on December 12, 2017, 06:07:33 PM
headlines todayhttps://www.npr.org/sections/thetwo-way/2017/12/12/570119468/arctics-temperature-continues-to-run-hot-latest-report-card-shows
Title: Re: The 2017/2018 freezing season
Post by: Dharma Rupa on December 13, 2017, 07:10:54 PM
I think it is beginning to look pretty clear that ever since 20151227 (Dec 27, 2015), this is the New Normal:
Title: Re: The 2017/2018 freezing season
Post by: Tor Bejnar on December 13, 2017, 08:01:40 PM
Although two years, statistically, won't determine a new state, it has only gotten 'cold' once in almost two years, according to the DMI 80N graphs (http://ocean.dmi.dk/arctic/meant80n.uk.php).

I wonder what the atmospheric physicists and climate modelers and such have to say about what could steadfastly maintain North Pole winter 'warmth'.
Title: Re: The 2017/2018 freezing season
Post by: jdallen on December 13, 2017, 08:58:07 PM
Although two years, statistically, won't determine a new state, it has only gotten 'cold' once in almost two years, according to the DMI 80N graphs (http://ocean.dmi.dk/arctic/meant80n.uk.php).

I wonder what the atmospheric physicists and climate modelers and such have to say about what could steadfastly maintain North Pole winter 'warmth'.
I'll hazard a predictive summary of their comments- warmer water, thinner ice, far greater inputs of moisture from lower latitudes.
Title: Re: The 2017/2018 freezing season
Post by: charles_oil on December 13, 2017, 09:34:09 PM


See the NOAA report thread
link=topic=2213.msg136159#msg136159 date=1513160047



Quote:
Despite relatively cool summer temperatures, observations in 2017 continue to indicate that the Arctic environmental system has reached a 'new normal', characterized by long-term losses in the extent and thickness of the sea ice cover, the extent and duration of the winter snow cover and the mass of ice in the Greenland Ice Sheet and Arctic glaciers, and warming sea surface and permafrost temperatures.
Title: Re: The 2017/2018 freezing season
Post by: Dharma Rupa on December 13, 2017, 10:28:19 PM
See the NOAA report thread
link=topic=2213.msg136159#msg136159 date=1513160047

Quote:
Despite relatively cool summer temperatures, observations in 2017 continue to indicate that the Arctic environmental system has reached a 'new normal', characterized by long-term losses in the extent and thickness of the sea ice cover, the extent and duration of the winter snow cover and the mass of ice in the Greenland Ice Sheet and Arctic glaciers, and warming sea surface and permafrost temperatures.

Otherwise known as WACC-y weather.
Title: Re: The 2017/2018 freezing season
Post by: jai mitchell on December 13, 2017, 11:41:15 PM
American Geophysical Union 2017 Press Conference on the Arctic Report Card

https://www.youtube.com/watch?v=1gTkcFUHn0w&t=2252s 
December 13, 2017

Title: Re: The 2017/2018 freezing season
Post by: A-Team on December 13, 2017, 11:50:02 PM
Quote
the Arctic environmental system has reached a 'new normal'
I sincerely doubt if anyone will step forward and admit to having writing that grossly misleading sentence but the implication -- that some sort of new 'equilibrium state' or pause in Arctic Amplification has set in -- is dead wrong.

The downward trend that continued in 2017 -- with record-setting delays in freeze-over in the western portal (Chukchi) --  is the exact opposite of the meaning of steady state in the physical sciences.

There is nothing normal about this trend. It is ever-worsening human disruption of climate by atmospheric emissions pollution.

Its consequences for mid-latitude weather are belatedly under discussion but will surely be exacerbated and possibly elevated to tipping point status as the trend takes us in the near term to even more extreme states.

In my view, the climate is undergoing unprecedented and largely unpredicted rapid change already, though very unevenly depending on location, eg the western coast of North America is hyper-sensitive to changes in the adjacent Pacific whereas as other areas might plod along at a barely noticeable 2ºC-by-2100.

For this reason, model papers that build on Old Arctic conditions should be rejected at the time of peer-review. It's not at all uncommon to read a December 2017 paper only to discover in the fine print that it assumes an entirely pre-2014 foundation.

Whoa ... a whole lot has happened since then, even with a discount for natural variation. Why wasn't that change in baseline conditions incorporated? A four year delay is unacceptable, long beyond the shelf life of utilizability. Only an eight of that is attributable to journal review.

I follow near-real and annual changes quite closely and have provided several thousand time series so that carefully sourced current data is readily available to even the laziest scientist on the planet. So what's the excuse for all the dilatory papers?

Perhaps the most disturbing example of not acknowledging the walrus in the tent is the Beaufort Gyre, which appears long-gone. In my view, it won't ever be coming back to what it was.

If you are too new here to remember the Beaufort Gyre, it was a quasi-stationary pattern in atmospheric highs and lows give rise to winds that caused a portion of the ice pack to circle tightly around for years in the Beaufort Sea. The same floes would thicken each winter and melt some each summer, extruding brine from recrystallizing ice and giving rise to a large reservoir of slightly less salty water (called a freshwater pool in oceanography).

I've reposted NSIDC's 1979-2015 sea ice age animation here many times. It uses weekly intervals which are very effective in displaying the years and seasons in which the Beaufort Gyre, TransArctic Drift and Fram Strait export were actually active.

Those don't include the most recent years. The weather pattern is just not re-establishing itself except episodically. Even when it does, there's no gyre, only a counter-current to the Alaskan Coastal Current that takes the ice -- now 79% first-year -- into the killing fields of the Chukchi. Remember the route traced by Big Block last year?

The Beaufort Sea today melts out completely every August and is late to refreeze. There is zero multi-year ice circling the Beaufort Gyre, though you would never know it from journal articles that go on and on about ye Olde Gyre like there was no tomorrow.

All gradients tend to dissipate. That's the second law of thermodynamics. Without continuing energy inputs from wind and current, there's nothing here to sustain former temperature, salinity, buoyancy gradients in the Beaufort Gyre center. They're dissipating. Gradients in nature are not sustained by claims in dead-on-arrival model papers.

The Arctic is changing too fast for the modeling community to keep up.  It's better to stay in the present.  So sleep well, the AMOC isn't safe but it won't be the Beaufort Gyre that does it in.

I'll post the year-in-review videos in due course.
Title: Re: The 2017/2018 freezing season
Post by: Reallybigbunny on December 14, 2017, 01:04:10 AM
Nice summary, thanks A-Team!!!
Title: Re: The 2017/2018 freezing season
Post by: Daniel B. on December 14, 2017, 02:53:39 AM
Perhaps they were just referring to a new normal in sea ice minima, which have leveled off over the past decade.  Just a thought.
Title: Re: The 2017/2018 freezing season
Post by: miki on December 14, 2017, 05:01:22 AM
Thanks A-Team. To call "new normal" a speeding transition seems to me narrow and misleading at the best.
Title: Re: The 2017/2018 freezing season
Post by: Pmt111500 on December 14, 2017, 05:44:11 AM
Thanks A-team,

The 'new normal' is indeed quite a funny phrase. I've used it oftener than I would have liked but since there are people who do not acknowledge the melt in Greenland, this has been a funny way to incorporate dynamic change and huuge decreases in volume of ice in the 'normal'. I agree it's mostly a semantic trick to avoid saying 'your life wrt weather is about to experience some drastic changes.'
Title: Re: The 2017/2018 freezing season
Post by: Pmt111500 on December 14, 2017, 06:12:34 AM
Wrt Beaufort Gyre, the movement vectors of this have been traditionally been seen as a sum of coriolis-force generated current on top of the world and the atmospheric polar cell east winds circulating the Arctic High. This results in a clockwise circulation that can be interrupted only by large influxes of water, be it oceanic or fresh. As we've seen in recent years the high in arctic regularly breaks thus weakening the circulation and giving the influxes of water and high latitude low pressures a lower þreshold to actually switch the direction to counterclockwise rotation. This would help to keep the Atlantic border of icy waters more stable than the Pacific side which could be what we're nowadays seeing. The 'deadliest catch' crews might someday end up in Barrow in their final season.
Title: Re: The 2017/2018 freezing season
Post by: Pmt111500 on December 14, 2017, 06:25:47 AM
previously, the semi-permanent Aleutian low has driven most of the waters entering from the Pacific towards the East Siberian sea from whence they Transpolar Drifted to N. Atlantic. With the Beaufort lows we're seeing more regularly now the influx is directed more to stay in Chucki even trying to enter Beaufort east of Barrow. Should check some recent measurements if they're publicly available in the current political climate (thats not a forbidden phrase, i guess), so take these three posts with a grain of sand (my attempts to summarize science usually have at least a glitch or two)
Title: Re: The 2017/2018 freezing season
Post by: Neven on December 14, 2017, 03:21:20 PM
On the ASIB I have used 'new abnormal' in the past.   ;D
Title: Re: The 2017/2018 freezing season
Post by: Neven on December 14, 2017, 03:38:12 PM
A-Team, maybe you've already seen this (if not, sorry for not posting earlier):

Quote
Special issue to highlight impact of changes in Arctic climate (https://www.eurekalert.org/pub_releases/2017-12/ioap-sit112917.php)
INSTITUTE OF ATMOSPHERIC PHYSICS, CHINESE ACADEMY OF SCIENCES

There's controversy in climate change research--not whether climate change exists, but how the evidence is gathered and used to inform predictions. To help bring convergence to the field and potentially accelerate action, a special issue of the Advances in Atmospheric Sciences is highlighting recent scientific work.

"Our understanding of Arctic-midlatitude linkages is still at a pre-consensus stage," said Thomas Jung, a professor of climate dynamics at the Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research in Bremerhaven, Germany. He also co-authored the issue's preface as a guest editor. "...it is important, therefore, to bring together the latest research results."

Titled, "Towards improving understanding and prediction of Arctic change and its linkage with Eurasian mid-latitude weather and climate" ---or "Impact of a Rapidly Changing Arctic on Eurasian Climate and Weather" for short---the special issue focuses on understanding how changes in the Arctic influence the mid-latitude regions of the globe. These areas sandwich the central tropical region. They are capped by the Earth's poles, and include Europe, most of Asia, north Africa, and much of North America.

While the increased near-surface temperature of the Arctic and the significantly decreased sea ice are undisputed facts, the link between such changes and the extreme climate and weather events in the mid-latitudes is still debated.

"The results published in the journal further present where divergence occurs," said the lead editor of the special issue and preface co-author Xiangdong Zhang, a professor at the International Arctic Research Center at the University of Alaska Fairbanks in the United States. Zhang noted that this knowledge will help scientists identify areas in need of collaborative work.

The special issue includes observational results and modelling work on the problem of Arctic and Eurasian climate links, yet the work does not yet clarify the correlation. According to Zhang, areas of progress include the use of different prediction models, an increased data sample size with the help of coupled model simulations, as well as more focus on regional linkages. The entire Northern Hemisphere was examined, rather than distinct zones.

And sorry for the off-topic.
Title: Re: The 2017/2018 freezing season
Post by: numerobis on December 14, 2017, 06:57:32 PM
Quote
the Arctic environmental system has reached a 'new normal'
I sincerely doubt if anyone will step forward and admit to having writing that grossly misleading sentence but the implication -- that some sort of new 'equilibrium state' or pause in Arctic Amplification has set in -- is dead wrong.

The downward trend that continued in 2017 -- with record-setting delays in freeze-over in the western portal (Chukchi) --  is the exact opposite of the meaning of steady state in the physical sciences.

The quote you're replying to doesn't claim there's an equilibrium state or a pause -- quite the opposite.

The normal thing to expect in the Arctic now is that it's warming fast and sea ice is trending down fast.
Title: Re: The 2017/2018 freezing season
Post by: gerontocrat on December 15, 2017, 10:36:28 AM
In my view, the climate is undergoing unprecedented and largely unpredicted rapid change already, though very unevenly depending on location, eg the western coast of North America is hyper-sensitive to changes in the adjacent Pacific whereas as other areas might plod along at a barely noticeable 2ºC-by-2100.

For this reason, model papers that build on Old Arctic conditions should be rejected at the time of peer-review. It's not at all uncommon to read a December 2017 paper only to discover in the fine print that it assumes an entirely pre-2014 foundation.

Whoa ... a whole lot has happened since then, even with a discount for natural variation. Why wasn't that change in baseline conditions incorporated? A four year delay is unacceptable, long beyond the shelf life of utilizability. Only an eight of that is attributable to journal review.

I follow near-real and annual changes quite closely and have provided several thousand time series so that carefully sourced current data is readily available to even the laziest scientist on the planet. So what's the excuse for all the dilatory papers?

The Arctic is changing too fast for the modeling community to keep up.

Some months ago I had a look at the timeline for CMIP6 and IPCC AR6 and did wonder about timings.

The IPCC is currently in its Sixth Assessment cycle. During this cycle, the Panel will produce three Special Reports, a Methodology Report on national greenhouse gas inventories and the Sixth Assessment Report (AR6).
 
"The 43rd Session of the IPCC held in April 2016 agreed that the AR6 Synthesis Report would be finalized in 2022 in time for the first UNFCCC global stocktake when countries will review progress towards their goal of keeping global warming to well below 2 °C while pursuing efforts to limit it to 1.5 °C. The three Working Group contributions to AR6 will be finalized in 2021."

So reports finalised in 2021 / 2022.

The timeline for the modelling and associated science is somewhat different. See image below. Will new data from 2018, 2019, 2020 data even get considered?
Title: Re: The 2017/2018 freezing season
Post by: numerobis on December 15, 2017, 04:04:44 PM
957 hPa off Labrador. Up goes the temperature! The high was -8 C last night, whereas a normal high is about -19 C (and occurs during the day).

It's rolling around for the next couple days before dissipating on Sunday. Then there'll be a week of normal temperatures.

As I mentioned, Frobisher Bay froze over this week. Snow is starting to pile on top of the ice; there's only a few open leads left. I'm assuming the holiday festivities will be able to get out on the ice, but we were within a week or so of needing to cancel some of the events.

(Wish my pilot luck on landing here to pick us up for the holidays!)
Title: Re: The 2017/2018 freezing season
Post by: Daniel B. on December 15, 2017, 06:16:59 PM
Quote
the Arctic environmental system has reached a 'new normal'
I sincerely doubt if anyone will step forward and admit to having writing that grossly misleading sentence but the implication -- that some sort of new 'equilibrium state' or pause in Arctic Amplification has set in -- is dead wrong.

The downward trend that continued in 2017 -- with record-setting delays in freeze-over in the western portal (Chukchi) --  is the exact opposite of the meaning of steady state in the physical sciences.

The term "new normal," is somewhat nebulous, and not well defined by NOAA.  It could refer to the observations of either declining sea ice maxima or plateauing sea ice minima.  Their report mentions both warming winter temperatures and cooling summer temps.
The quote you're replying to doesn't claim there's an equilibrium state or a pause -- quite the opposite.

The normal thing to expect in the Arctic now is that it's warming fast and sea ice is trending down fast.
Title: Re: The 2017/2018 freezing season
Post by: GeoffBeacon on December 15, 2017, 07:32:45 PM
geronocrat
Quote
So reports [for AR6?] finalised in 2021 / 2022.

The timeline for the modelling and associated science is somewhat different. See image below. Will new data from 2018, 2019, 2020 data even get considered?

Does that mean a 2 to 5 year lag between data and reports?

What happened in AR5?
Title: Re: The 2017/2018 freezing season
Post by: gerontocrat on December 15, 2017, 07:46:01 PM
geronocrat
Does that mean a 2 to 5 year lag between data and reports?

What happened in AR5?

I do not know, but the answer is likely to be yes - both for AR5 & AR6. They do not seem to be geared up for the speed of climate change and development of new data sources. Perrhaps A-Team knows more.
Title: Re: The 2017/2018 freezing season
Post by: oren on December 16, 2017, 11:39:38 AM
A-Team thank you for summarizing everything so bluntly. Sometimes it's easy to forget the big picture.
Title: Re: The 2017/2018 freezing season
Post by: Jim Hunt on December 16, 2017, 02:18:31 PM
And sorry for the off-topic.

Actually it rather reinforces A-Team's point. E.g.

"Record low sea-ice concentration in the central Arctic during summer 2010"

Zhao, J., Barber, D., Zhang, S. et al. Adv. Atmos. Sci. (2018) 35: 106. https://doi.org/10.1007/s00376-017-7066-6
Title: Re: The 2017/2018 freezing season
Post by: Hyperion on December 17, 2017, 01:02:34 AM
geronocrat
Quote
So reports [for AR6?] finalised in 2021 / 2022.

The timeline for the modelling and associated science is somewhat different. See image below. Will new data from 2018, 2019, 2020 data even get considered?

Does that mean a 2 to 5 year lag between data and reports?

What happened in AR5?

Actually I'm afraid it means a 7-10 year lag between data and IPCC reports. They are constrained to base their reports only on data presented in peer reviewed papers. The time required for funding proposals, the study, the write up, the peer review rarely comes in under 7-10 years.
And to pass peer review the politics require you to only quote data and other studies that have been peer reviewed also. Or the old crusties will knife it because its conflicting with the out of date science they contributed to. Such is how politics holds back science in the world we have to bear.
Title: Re: The 2017/2018 freezing season
Post by: Brigantine on December 17, 2017, 02:04:23 AM
While 2017-18 recorded the second earliest appearance of ice on the Great Lakes, it has now fallen to the 6th highest ice coverage for the date (5.2% (https://www.glerl.noaa.gov/res/glcfs/glcfs.php?lake=l&ext=ice&type=N&hr=00) on 2017-12-16) in the 46 year record (xls) (https://www.glerl.noaa.gov/data/ice/DailyAverages1973-2017.xlsx).

Top 10 seasons with the highest ice cover on Dec 16: (mean 2.1%, median 0.4%)
1. 1976-77 - 17.5%
2. 2013-14 - 12.3%
3. 1995-96 - 6.9%
4. 1985-86 - 6.5%
5. 2010-11 - 5.9%
6. 2017-18 - 5.2%
7. 2000-01 - 4.9%
8. 2005-06 - 4.6%
9. 1989-90 - 4.3%
10. 2008-09 - 4.2%
Title: Re: The 2017/2018 freezing season
Post by: jai mitchell on December 17, 2017, 06:55:54 AM
geronocrat
Quote
So reports [for AR6?] finalised in 2021 / 2022.

The timeline for the modelling and associated science is somewhat different. See image below. Will new data from 2018, 2019, 2020 data even get considered?

Does that mean a 2 to 5 year lag between data and reports?

What happened in AR5?

As I recall the Cutoff date was December '12 with publication in November 13.  However most of the papers cited were more than a few years old with the period of data often collected and synthesized into a paper within a year.  So I would guess average 'new' paper addition was 2010 or so with the 'new' data from 2008-2009.  However, we must remember that the communication of the ARs takes years to get into policy (or even the public awareness).  We are literally working on documents that still rely on TAR and AR4.
Title: Re: The 2017/2018 freezing season
Post by: aperson on December 18, 2017, 02:35:32 AM
GFS is showing strong Lows on both the Atlantic and Pacific sides that will efficiently transport heat into the Arctic on both sides:

https://earth.nullschool.net/#2017/12/19/0000Z/wind/surface/level/overlay=temp/orthographic=-90.25,84.42,693/loc=170.609,59.266
https://earth.nullschool.net/#2017/12/19/0000Z/wind/surface/level/overlay=mean_sea_level_pressure/orthographic=-90.25,84.42,693/loc=170.609,59.266

This pattern should persist several days and looks to continue to stall the unprecedentedly slow refreeze in the Chukchi Sea. It appears to be a repeat of the synoptics from last week that stalled extent, and it appears that similar dual LP systems may phase in over Christmas as well.

On the Pacific side, it looks like the ridiculously resilient ridge that's keeping California in Red Flag conditions is forcing the LP waves in the pacific to divert northward into the Arctic. CFS forecasts the Bering straight to be anomalously warm throughout the rest of the freezing season: http://www.cpc.ncep.noaa.gov/products/CFSv2/htmls/glbT2me1Sea.html
Title: Re: The 2017/2018 freezing season
Post by: Pavel on December 18, 2017, 09:37:04 PM
Yes, the sun is going to turn back to the north and the Chukchi sea still has not experienced the real coldness. If the spring and June will be snowy one can keep calm, otherwise things could get to the new record lows
Title: Re: The 2017/2018 freezing season
Post by: kiwichick16 on December 18, 2017, 11:41:43 PM
Thanks Pavel.......looks like there is a spot near the Arctic coast of Alaska that is approaching 30 degrees C above normal
Title: Re: The 2017/2018 freezing season
Post by: Jim Hunt on December 19, 2017, 12:12:14 AM
For those interested in sea ice age I've just stumbled across a new paper by Pierre Rampal et al. on The Cryosphere Discuss:

"A new tracking algorithm for sea ice age distribution estimation (https://doi.org/10.5194/tc-2017-250)"

Quote
It is the purpose of the present paper to describe a method and a derived dataset that allow us to shed more light on the development of the age distribution of the Arctic sea ice. For this purpose, we have taken advantage of some new datasets on sea ice drift and concentration developed and distributed by the EUMETSAT Ocean and Sea Ice Satellite Application Facility (OSI SAF). In addition, we have developed a new Eulerian scheme of advection supported by the Sea Ice Climate Change Initiative (SICCI) project of the European Space Agency (ESA). These improvements have allowed us to produce a new sea ice age dataset which in each grid box contains not only the age of the oldest ice, but the actual age distribution provided as fractions of ice of different age categories (hereafter refered to as sea ice age fractions). The dataset will be presented and compared with earlier attempts to map Arctic sea ice age as well as with the standard products for sea ice type classification from scatterometer and microwave radiometer observations.

Note that these maps are all for the same date - January 1st 2016
Title: Re: The 2017/2018 freezing season
Post by: Adam Ash on December 19, 2017, 10:56:09 AM
The profession of 'Sea ice age calculator' is going to be a dying trade when the answer is never more than one!
Title: Re: The 2017/2018 freezing season
Post by: Thomas Barlow on December 20, 2017, 04:18:43 PM
""In an accompanying annual report on the Arctic’s health — titled “Arctic shows no sign of returning to reliably frozen region of recent past decades” — the National Oceanic and Atmospheric Administration, which oversees all official U.S. research in the region, coined a term: “New Arctic.”""

http://grist.org/article/let-it-go-the-arctic-will-never-be-frozen-again/
Title: Re: The 2017/2018 freezing season
Post by: litesong on December 21, 2017, 01:47:13 AM
Just to remind everyone, while present monthly Arctic sea ice Volume losses compared to 1980 decade average, vary  from ~ 9000 cubic kilometers to 10,500+ cubic kilometers:
For 390+ STRAIGHT months, global temperatures have been over the 20th century..... despite the  Total Solar Irradiation (TSI) being languid for many decades AND low for 11 years (including a 3+ year period, when TSI set a 100 year record low). The energy needed to melt 9000 to 10,500 cubic kilometers of ice is 25-35 times the annual U.S. energy consumption.
Title: Re: The 2017/2018 freezing season
Post by: meddoc on December 21, 2017, 09:21:55 AM
Yes, the sun is going to turn back to the north and the Chukchi sea still has not experienced the real coldness. If the spring and June will be snowy one can keep calm, otherwise things could get to the new record lows

Yes the PV just collapsed overnight into a 1 core- System over Siberia

Title: Re: The 2017/2018 freezing season
Post by: Thomas Barlow on December 21, 2017, 07:15:28 PM
Winter Solstice.
Lincoln Sea still broken up, ice still flowing south through Nares.
Title: Re: The 2017/2018 freezing season
Post by: Shared Humanity on December 22, 2017, 04:43:31 AM
The CAA is wearing corduroy!
Title: Re: The 2017/2018 freezing season
Post by: Ice Shieldz on December 22, 2017, 06:04:28 AM
Now without the corduroy, the last 10 days, contrast enhanced of Nares mouth & Lincoln Sea.
Title: Re: The 2017/2018 freezing season
Post by: oren on December 22, 2017, 07:45:54 AM
Great animation, thank you Ice Shieldz.
It will probably freeze over by February.
Title: Re: The 2017/2018 freezing season
Post by: Alexander555 on December 22, 2017, 01:38:40 PM
Looks like the polar vortex is going to blow some cold wind across the US. If i'm right that's because the jet stream is weak. But i have no idea about the scale of that cold burst. For example, can it have an impact on how much ice we get on the arctic this year ? Or is it to small for that ? Because normaly that jet stream keeps that cold weather above the arctic. And if i'm right that jet stream is behaving more unstable the last years. Is there any consensus why it is more unstable ?
Title: Re: The 2017/2018 freezing season
Post by: Thomas Barlow on December 22, 2017, 03:36:17 PM
Great animation, thank you Ice Shieldz.
It will probably freeze over by February.
There might need to be a thread to take bets on that.  :)
Title: Re: The 2017/2018 freezing season
Post by: Thomas Barlow on December 22, 2017, 03:38:44 PM
Now without the corduroy, the last 10 days, contrast enhanced of Nares mouth & Lincoln Sea.
Awesome!
One of those on the 1st of every month could be great.  :)
Title: Re: The 2017/2018 freezing season
Post by: aperson on December 23, 2017, 04:44:13 AM
It looks like Chukchi Sea / Bering Strait may see some cold temperatures reach it in the near future, but the source is pretty unusual. GFS has been showing a divergence zone setting up over the Arctic around Christmas for a while now and it looks like it will probably verify. This appears to be due to upper level transport from the Pacific to the Atlantic.

I'm not sure how unusual this pattern is, but I haven't encountered it before and perusing previous freezing season didn't show any immediate correlates. It seems like it will create a scenario that supports a large amount of export on both the Atlantic and Pacific sides even if it does transport more cold air from the Canadian and Siberian sides. I also note that the Siberian and Canadian sides are essentially stratified in this setup.

https://earth.nullschool.net/#2017/12/26/0300Z/wind/isobaric/250hPa/orthographic=-69.42,72.50,288/loc=156.152,81.878
https://earth.nullschool.net/#2017/12/26/0300Z/wind/surface/level/overlay=temp/orthographic=-69.42,72.50,288/loc=156.152,81.878
Title: Re: The 2017/2018 freezing season
Post by: Daniel B. on December 23, 2017, 02:57:10 PM
Looks like the polar vortex is going to blow some cold wind across the US. If i'm right that's because the jet stream is weak. But i have no idea about the scale of that cold burst. For example, can it have an impact on how much ice we get on the arctic this year ? Or is it to small for that ? Because normaly that jet stream keeps that cold weather above the arctic. And if i'm right that jet stream is behaving more unstable the last years. Is there any consensus why it is more unstable ?

Perhaps the 2013 and 2014 years may give some insight.  They were characterized by similar occurrences.
Title: Re: The 2017/2018 freezing season
Post by: prairiebotanist on December 23, 2017, 05:45:03 PM
Looks like the polar vortex is going to blow some cold wind across the US. If i'm right that's because the jet stream is weak. But i have no idea about the scale of that cold burst. For example, can it have an impact on how much ice we get on the arctic this year ? Or is it to small for that ? Because normaly that jet stream keeps that cold weather above the arctic. And if i'm right that jet stream is behaving more unstable the last years. Is there any consensus why it is more unstable ?

Perhaps the 2013 and 2014 years may give some insight.  They were characterized by similar occurrences.

I can't speak to the consequences of the coming North American arctic blast for the arctic, but in my part of the US (Wisconsin), the forecast cold is less intense than the coldest we expect, on average, in a given year, and cold of the forecast intensity and duration usually occurs a few times in any given winter, so there is not much that is exceptional about it.
Title: Re: The 2017/2018 freezing season
Post by: Alexander555 on December 23, 2017, 09:11:22 PM
Yes, the sun is going to turn back to the north and the Chukchi sea still has not experienced the real coldness. If the spring and June will be snowy one can keep calm, otherwise things could get to the new record lows

Where do you think that heat comes from ? Because that's a big difference , 20 to 25 degree more than normal. I have no idea if it's related. But i do remember we had a heatwave in the south of Europa and the north of Africa not that long ago. It was a pretty late heatwave.  Maybe that extra heat is moving into the arctic, creating a vortex-shot for the US and China.
Title: Re: The 2017/2018 freezing season
Post by: aperson on December 23, 2017, 09:36:24 PM
Where do you think that heat comes from ? Because that's a big difference , 20 to 25 degree more than normal. I have no idea if it's related. But i do remember we had a heatwave in the south of Europa and the north of Africa not that long ago. It was a pretty late heatwave.  Maybe that extra heat is moving into the arctic, creating a vortex-shot for the US and China.

Synoptics are transporting a large amount of warm moist air from the ITCZ up to the Bering Strait. It's easy to see when looking at total precipitable water content: https://earth.nullschool.net/#current/wind/surface/level/overlay=total_precipitable_water/orthographic=-164.89,21.69,360/loc=-138.903,28.840

Essentially, the same ridging that is keeping California dry is sending this atmospheric river up to the Arctic instead. However, it should be getting cut off over the next day: https://i.imgur.com/H98cphq.gif but in the meantime it will bring cloud cover and precipitation (including a good deal of rain) around the Bering Strait and Chukchi Sea

Jet stream transport at the upper troposphere is also holding onto its Pacific -> Atlantic pattern. Model soundings show an upper level temperature inversion which indicates a large amount of heat transport occurring from the Pacific side up to the Arctic (and even over to the Atlantic side) in the upper troposphere (second attachment).

Title: Re: The 2017/2018 freezing season
Post by: aperson on December 24, 2017, 04:06:49 AM
The following two references attribute these warm air intrusions to MJO phase 7 warming in tandem with Maritime Continent convection. Note that the effects of this transport are positively correlated with Zonal Available Potential Energy which is maximal during Arctic night (see: http://jasoncordeira.weebly.com/atmospheric-energy.html)

http://journals.ametsoc.org/doi/full/10.1175/JAS-D-16-0033.1
Title: An Investigation of the Presence of Atmospheric Rivers over the North Pacific during Planetary-Scale Wave Life Cycles and Their Role in Arctic Warming

Extract: During the planetary-scale wave life cycle, synoptic-scale waves are diverted northward over the central North Pacific. The warm conveyor belts associated with the synoptic-scale waves channel moisture from the subtropics into atmospheric rivers that ascend as they move poleward and penetrate into the Arctic near the Bering Strait. At this time, the synoptic-scale waves undergo cyclonic Rossby wave breaking, which further amplifies the planetary-scale waves. The planetary-scale wave life cycle ceases as ridging over Alaska retrogrades westward. The ridging blocks additional moisture transport into the Arctic. However, sensible and latent heat amounts remain elevated over the Arctic, which enhances downward infrared radiation and maintains warm surface temperatures.


http://journals.ametsoc.org/doi/10.1175/JCLI-D-15-0502.1
Title: The Influence of the Madden–Julian Oscillation on Northern Hemisphere Winter Blocking

Extract: Utilizing a two-dimensional blocking index, composites of North Pacific, North Atlantic, and European blocking are generated relative to MJO phase. In the west and central Pacific, all MJO phases demonstrate significant changes in blocking, particularly at high latitudes. A significant decrease in east Pacific and Atlantic blocking occurs following phase 3 of the MJO, characterized by enhanced convection over the tropical East Indian Ocean and suppressed convection in the west Pacific. The opposite-signed MJO heating during phase 7 is followed by a significant increase in east Pacific and Atlantic blocking.


The first paper provides December 1, 2007 as an analogue that induced Pacific side warming. I believe the warming event occurring today is similar due to a similar synoptic setup. In particular, they are similar in terms of MJO phase and strength and effect on the Bering Strait. The effect in 2017 seems less pronounced alongside a weaker phase 7 MJO. MJO phase diagram and T2m anomalies are attached for each event. 500mb height anomalies and 65N model soundings are also similar, however I have not included these.
Title: Re: The 2017/2018 freezing season
Post by: Hyperion on December 24, 2017, 04:48:06 AM
The recently persistent windflow in through Bering seems to have been effective in keeping the shallow continental shelf area well mixed.
Today for example Nullschool is showing waves over 2.3m pounding the Chuchki ice from the south. Whilst despite warm influx waters from the north Pacific, helped in no small part by recent persistent southward winds on the Atlantic side no doubt, we have negative SSTAs in the Chuchki suggesting higher than normal salinity.

The whole Pacific sea temperatures situation is unprecedentedly whacko in fact, with SSTAs off northern Japan and in the south Tasman Reaching +5 degrees C and a belt of water halfway across the Pacific at the Equator from sth America of cooler SST than 40deg nth or sth latitude in the western Pacific. 
Title: Re: The 2017/2018 freezing season
Post by: Alexander555 on December 24, 2017, 09:55:24 AM
Starts to look like winter.
Title: Re: The 2017/2018 freezing season
Post by: gerontocrat on December 24, 2017, 01:23:43 PM
Canada and the USA are certainly being clobbered with really freezing weather - but look at the Arctic, a different story.
Title: Re: The 2017/2018 freezing season
Post by: Dharma Rupa on December 24, 2017, 02:59:39 PM
Canada and the USA are certainly being clobbered with really freezing weather - but look at the Arctic, a different story.

WACC-y weather.
Title: Re: The 2017/2018 freezing season
Post by: Thomas Barlow on December 24, 2017, 11:51:39 PM
No biggie, but it appears that sea-ice extent is the 2nd lowest on record for this date (with 2016 the lowest. 2010 close)

http://nsidc.org/arcticseaicenews/charctic-interactive-sea-ice-graph/
Title: Re: The 2017/2018 freezing season
Post by: aperson on December 25, 2017, 12:56:12 AM
Canada and the USA are certainly being clobbered with really freezing weather - but look at the Arctic, a different story.

WACC-y weather.

Yeah, I think some of the puzzle pieces are coming together for me on this. Pronounced MJO Phase 7 results in WPAC blocking and subsequent pacific -> atlantic heat and moisture transport across the Arctic. Pronounced MJO Phase 3 results in Atlantic blocking and subsequent atlantic -> pacific heat and moisture transport across the Arctic. Each of these stratify air parcels so that the Siberian and Canadian sides don't mix. This results in tropical air transport across the arctic while the cold pools on each side are forced to move to midlatitudes instead of into the Arctic.
Title: Re: The 2017/2018 freezing season
Post by: Alexander555 on December 25, 2017, 09:35:27 AM
Great animation, thank you Ice Shieldz.
It will probably freeze over by February.
There might need to be a thread to take bets on that.  :)


That sounds like a good idea. Many things you can put a bet on. It can generate extra money for research. And it sounds like fun. If you look at the pic below, the jet stream is related to it, some accumulation of heat, if you can give these things a source, so that you can monitor it. Than we could make a bet on how far and where it will push the cold out of the arctic. And maybe a good way to get more peope involved in what is happening to our planet.
Title: Re: The 2017/2018 freezing season
Post by: meddoc on December 25, 2017, 10:01:44 AM
Looks like SHTF Big- time to me. Arctic Cold tossed out of Place, while there are literally Waterbombs Circling around the Globe. I would bet an El Nino is already underway. If not a global Ocean- to Atmosphere Heat Transfer. Time to ramp up Things u still have in the Bucket List!

Oh- & be careful with Flying. Tropical, and North- Atlantic, especially.
Title: Re: The 2017/2018 freezing season
Post by: Dharma Rupa on December 25, 2017, 08:02:52 PM
Looking at this, it might be more accurate to say Warm Arctic Cold Oceans.  The continents over the last 365 days have been sort of meh.  We've remarked for awhile about the Atlantic cold spot, but it seems maybe the Pacific has one too now.
Title: Re: The 2017/2018 freezing season
Post by: aperson on December 26, 2017, 05:21:03 AM
As expected, the closure of the atmospheric river on the Pacific has lead to warm moist air transporting across the Arctic and temperature anomalies trending back closer to normal. While they'll still be high, they should be low enough to promote refreeze along the Chukchi and Bering Strait throughout New Year.

Continued -EPO conditions promote warm air advection into the Arctic still, and these conditions could easily reoccur later in winter if this -EPO trend does not change.
Title: Re: The 2017/2018 freezing season
Post by: Wherestheice on December 26, 2017, 08:23:35 AM
Hello fellow members. I just joined this forum. Just letting you all know i'm here :)
Title: Re: The 2017/2018 freezing season
Post by: El Cid on December 26, 2017, 10:14:59 AM
I've been reading this forum for quite a while and it seems - just like last summer - that with 2017 sea ice having come up to 2nd place (meaning 2nd lowest) people are getting excited again, and we start to see the same sentiment that always prevails when ice extent is very low. With this come the usual forecasts of imminent collapse of sea ice (and all life an Earth :D).
I believe this is wrong. Noone, meaning noone can forecast a chaotic system and Arctic Sea Ice being one, it is impossible to say whether we are going to lose (most of) all summer ice in 2018 or 2048. I do appreciate hard data, studies and facts and all the people who contribute, but the expectation of miracles and wild, baseless forecasts (which in fact are not forecasts at all) are really unnecessary and tiresome.
Also, the world will not come to an end when we lose ASI although it seems to me that many people on this forum hope (and at the same tiime dread) to see just that, only to prove them right and everyone around them wrong.
I think that losing the ice is now fait accompli, not much can be done about that. The only question is adaptation which is still possible. Dreaming about the apocalypse is just a waste of time which could be spent much better, preparing for (possibbly very abrupt) climate change.

Anyway, I wanted to write about these things last summer, and even 2016 autumn. I promise not to be so offtopic next time. Thanks everyone for the effort and all the valuable contribution!
Title: Re: The 2017/2018 freezing season
Post by: meddoc on December 26, 2017, 11:00:17 AM
Just when u thought u were out of the water
Title: Re: The 2017/2018 freezing season
Post by: Wherestheice on December 26, 2017, 11:20:38 AM
I've been reading this forum for quite a while and it seems - just like last summer - that with 2017 sea ice having come up to 2nd place (meaning 2nd lowest) people are getting excited again, and we start to see the same sentiment that always prevails when ice extent is very low. With this come the usual forecasts of imminent collapse of sea ice (and all life an Earth :D).
I believe this is wrong. Noone, meaning noone can forecast a chaotic system and Arctic Sea Ice being one, it is impossible to say whether we are going to lose (most of) all summer ice in 2018 or 2048. I do appreciate hard data, studies and facts and all the people who contribute, but the expectation of miracles and wild, baseless forecasts (which in fact are not forecasts at all) are really unnecessary and tiresome.
Also, the world will not come to an end when we lose ASI although it seems to me that many people on this forum hope (and at the same tiime dread) to see just that, only to prove them right and everyone around them wrong.
I think that losing the ice is now fait accompli, not much can be done about that. The only question is adaptation which is still possible. Dreaming about the apocalypse is just a waste of time which could be spent much better, preparing for (possibbly very abrupt) climate change.

Anyway, I wanted to write about these things last summer, and even 2016 autumn. I promise not to be so offtopic next time. Thanks everyone for the effort and all the valuable contribution!

The media tends to focus on ice extent, but really what we should be talking about is sea ice volume. I don't have the data with me currently, but the sea ice volume has decreased rapidly in recent decades. As far as the end of the world goes.... Losing the arctic in my own opinion won't end the world, but it will cause the earth to become less habitable. People tend to look at climate change in multiple views... ice decline, heat waves, species extinction, change in weather, etc. If you add everything into one conclusion, you get utter disaster. The observations in the field are getting more and more deadly than ever, and if we want to sustain human life on earth.... we will need to see the changes needed completed within the next decade. My conclusion based off my own personal research is once we lose the arctic, we lose the globe, and based off observations were getting close.
Title: Re: The 2017/2018 freezing season
Post by: Tor Bejnar on December 26, 2017, 04:18:17 PM
Focusing on "volume" has its merits, as ice grows or shrinks via 3-dimensional molecules (via the physical chemistry that works in this 3-dimensional realm), but is minimally measured (mostly modeled).  When the sun shines, albedo (causing or suppressing solar heat gain) is strongly affected by sea ice area (SIA), so it is a significant component of Arctic health.  Finally, sea ice extent (SIE) is meaningful, partly because it is more accurately measured, and partly because the difference between SIE and SIA gives some clues as to mid-ice sheet albedo (thus melting).  (Warm marginal seas will affect future ice (or lack thereof) in those areas, but doesn't much affect Central Arctic Basin (CAB) melting.)

But as this is the "freezing" thread, we note that low SIA means there is open water where there used to be ice with the resulting significant transfer of heat from this water to the atmosphere, increasing temperature and humidity, and, most likely, snowfall on nearby ice.  "Warm" (less severely cold) air depresses ice volume growth, as does increased snow cover (more insulation).  Thick ice (other parameters being equal) thickens much more slowly than thin ice (due to 'self-insulation', basically).  (So, here we are, back to volume!)

Yup, it's all important, and crucial to our deepening understanding of Arctic sea ice!
Title: Re: The 2017/2018 freezing season
Post by: Daniel B. on December 28, 2017, 03:24:58 PM
Focusing on "volume" has its merits, as ice grows or shrinks via 3-dimensional molecules (via the physical chemistry that works in this 3-dimensional realm), but is minimally measured (mostly modeled).  When the sun shines, albedo (causing or suppressing solar heat gain) is strongly affected by sea ice area (SIA), so it is a significant component of Arctic health.  Finally, sea ice extent (SIE) is meaningful, partly because it is more accurately measured, and partly because the difference between SIE and SIA gives some clues as to mid-ice sheet albedo (thus melting).  (Warm marginal seas will affect future ice (or lack thereof) in those areas, but doesn't much affect Central Arctic Basin (CAB) melting.)

But as this is the "freezing" thread, we note that low SIA means there is open water where there used to be ice with the resulting significant transfer of heat from this water to the atmosphere, increasing temperature and humidity, and, most likely, snowfall on nearby ice.  "Warm" (less severely cold) air depresses ice volume growth, as does increased snow cover (more insulation).  Thick ice (other parameters being equal) thickens much more slowly than thin ice (due to 'self-insulation', basically).  (So, here we are, back to volume!)

Yup, it's all important, and crucial to our deepening understanding of Arctic sea ice!

I agree with everything you said.  I would just emphasize the part about extent being most accurately measured.  For that reason, I focus more on those numbers.  All the others will follow suit.
Title: Re: The 2017/2018 freezing season
Post by: aperson on December 28, 2017, 08:31:23 PM
GFS seems to think the -EPO pattern is going to keep persisting. One can easily see all that warm moist air getting sent up to the Arctic instead of pushing into the western US because of it: https://i.imgur.com/C4PfZwX.gifv

If this pattern holds, another juiced up MJO phase 7 next month would cause another round of extreme warm anomalies on the Pacific side.
Title: Re: The 2017/2018 freezing season
Post by: Clenchie on December 29, 2017, 03:37:31 PM
Would it be safe to assume that cold air has left the arctic and migrated to the US, lowering the temperature in the latter and raising it in the former?  If so, let's hope nothing similar happens here in the UK!
Title: Re: The 2017/2018 freezing season
Post by: Thomas Barlow on December 29, 2017, 04:32:09 PM
Closing in?
Title: Re: The 2017/2018 freezing season
Post by: El Cid on December 29, 2017, 05:02:21 PM
It seems to me that in the past winters it was either warm in Europe and cold in the US or the other way around, as if the cold air can "splash" out of the Arctic only in one direction and then it stays there. Is there any scientific explanation for that? Or are my "feelings" utterly baseless?
Title: Re: The 2017/2018 freezing season
Post by: Dharma Rupa on December 29, 2017, 05:46:33 PM
It seems to me that in the past winters it was either warm in Europe and cold in the US or the other way around, as if the cold air can "splash" out of the Arctic only in one direction and then it stays there. Is there any scientific explanation for that? Or are my "feelings" utterly baseless?
An east-west swing has been known here in the states since I was a kid in the 1950s.  In the winter, if it is warm in the west it is usually cold in the east -- and the reverse.  I think the pattern is a bit too complex to strictly say the same about Eurasia and America, but I'm sure there is some sort of pattern there.
Title: Re: The 2017/2018 freezing season
Post by: Jim Pettit on December 29, 2017, 05:47:08 PM
Closing in?

What are we looking at here?
Title: Re: The 2017/2018 freezing season
Post by: Avalonian on December 29, 2017, 06:31:05 PM
It seems to me that in the past winters it was either warm in Europe and cold in the US or the other way around, as if the cold air can "splash" out of the Arctic only in one direction and then it stays there. Is there any scientific explanation for that? Or are my "feelings" utterly baseless?

It's something I've often wondered at as well - as a generality rather than a rule. I also feel that the extreme cold excursions are much more likely to get into the US because the air is travelling south over cold land, rather than over the NAD with its frequent warm air transport. Most of the time, when the UK gets frozen badly, it seems to come from Eastern Europe instead of the North directly.

Of course, with the weakening jet stream and the cold blob off Greenland, *if* this is a real pattern then it's likely to become more irregular. I'm half-expecting a repeat of the extreme winter of '62-3 some year soon. But this may all be bunkum.

To stay on topic, though, such excursions have got to be tied into the limited ice growth and thickening in the Arctic Basin: cold W. European winters may correlate to some degree with early freeze of the Chukchi, for example. I'm betting that someone here has the data to look for patterns like that. Whether they have the energy is another matter entirely!
Title: Re: The 2017/2018 freezing season
Post by: FishOutofWater on December 29, 2017, 06:59:47 PM
The cold eastern U.S. / warm Europe and vice versa directly correlates with the North Atlantic Oscillation which is extensively described at many web sites. Google it.
Title: Re: The 2017/2018 freezing season
Post by: aperson on December 29, 2017, 07:04:14 PM
When looking at weather trends that affect the Arctic I'd recommend familiarizing oneself with the EPO (-EPO = more likely Pacific air intrusions), NAO (-NAO = more likely Atlantic air intrusions), and AO (-AO = cold is more poorly contained inside the polar jet), and of course the ENSO.

Strong MJO signals along the western tropical latitudes in tandem with one of these oscillations can indicate stronger convection to increase meridional warm, moist air transport (one can look at Total Precipitable Water maps to see the transport in action). Strong Phase 7 MJO in tandem with -EPO amplifies tropical moisture into the Pacific side. Strong Phase 3 MJO in tandem with -NAO amplifies tropical moisture into the Atlantic side.

-EPO in particular this season has been driving pacific-side warmth into the Arctic. GFS and Euro show another moisture intrusion happening around 7-10 days from now.
Title: Re: The 2017/2018 freezing season
Post by: Thomas Barlow on December 29, 2017, 07:29:23 PM
Closing in?
What are we looking at here?
↓ ↓ ↓
http://nsidc.org/arcticseaicenews/charctic-interactive-sea-ice-graph/
Title: Re: The 2017/2018 freezing season
Post by: subgeometer on December 30, 2017, 12:12:10 AM
Closing in?

What are we looking at here?

Extent I believe, currently second lowest for the date and closing in on last year
Title: Re: The 2017/2018 freezing season
Post by: subgeometer on December 30, 2017, 05:26:41 AM
The DMI SST anomaly map show shows a lot of warmth on the Atlantic side that will retard ice growth in that direction. What it doesn't show arethe temps of ice covered regions, but looking at the SST map reveals a large 'warm' area of the Alaskan/Canadian coast all the way to the Mackenzie delta left over from the huge area of open water that opened last summer. Much of the really cold ice is in the CAA. Continuing warm influxes from the Pacific will precondition the Chukchi etc for reall yrapid melt come spring.

Edit ; I fixed the transparency on the SST png.

Title: Re: The 2017/2018 freezing season
Post by: Iain on December 30, 2017, 10:47:10 AM
Contact:
https://ads.nipr.ac.jp/vishop/#/extent
Title: Re: The 2017/2018 freezing season
Post by: bosbas on December 30, 2017, 11:41:24 AM
Iain, you should label your plot 12-25 as it lists values from few days back.
Title: Re: The 2017/2018 freezing season
Post by: Iain on December 30, 2017, 11:56:00 AM
bosbas,

It was updated at 03:00 today, but averaged from the last couple of days. From the site:

"Averaging period and the update timing of daily data : In general, sea-ice extent is defined as a temporal average of several days (e.g., five days) in order to eliminate calculation errors due to a lack of data (e.g., for traditional microwave sensors such as SMMR and SSM/I). However, we adopt the average of latest two days (day:N & day:N-1) to achieve rapid data release. Only for the processing of WindSat data (Oct. 4, 2011 to the present) the data of the day before yesterday (day:N-2) is also sometimes used to fill data gaps."

Charctic updates mid afternoon from memory:
https://nsidc.org/arcticseaicenews/charctic-interactive-sea-ice-graph/
Title: Re: The 2017/2018 freezing season
Post by: gerontocrat on December 30, 2017, 04:06:37 PM
Will the remaning blob of open water in the Chukchi Sea survive until Jan 1 2018.

Did the polar bears stranded on Wrangel Island survive until the sea ice formed?

Image from NSIDc for 29 Dec.
Title: Re: The 2017/2018 freezing season
Post by: Pavel on December 30, 2017, 04:19:11 PM
The CAA ice looks really strong. The garlic press worked hard last fall and now it's "the Cold Pole". But on the other hand if the melting momentum in Summer will be strong enough, even like last Summer, this will lead to huge volume loss. Also the ice along the Siberian coast is strong but is prone to melt out in Summer anyway. And what we've got in the Chuckchi sea means we'll have some weak ice by the end of the freezing. Considering the fact the extent tracks at record lows now, things are getting exciting. If we'll get wet Spring and low clouds/snow in peack insolation time, the nuclear cannonball could be uploaded
Title: Re: The 2017/2018 freezing season
Post by: Thomas Barlow on December 30, 2017, 05:02:26 PM
Looks like by New Year's day (or earlier) could be the lowest extent on record for the date, starting off 2018 in a very bad place.

http://nsidc.org/arcticseaicenews/charctic-interactive-sea-ice-graph/
Title: Re: The 2017/2018 freezing season
Post by: gerontocrat on December 30, 2017, 08:34:53 PM
I guess eyes will be looking at the Atlantic side and the Pacific side for the remainder of extent gain.

For the next week or so it looks like weather in the Bering Sea is going to be ferocious. I wonder how that might impact sea ice formation ?
Title: Re: The 2017/2018 freezing season
Post by: Neven on December 30, 2017, 09:17:24 PM
I wonder how that might impact sea ice formation ?

I also wonder what it will mean for precipitation (snow) on the sea ice in the Pacific side of the Arctic? Last year, we saw what the train of Atlantic storms eventually meant for the melting season.
Title: Re: The 2017/2018 freezing season
Post by: Dharma Rupa on December 31, 2017, 02:41:43 PM
Not quite sure how it would be quantified, but it looks to me like the DMI 80N is settling into a much narrower temperature band that it used to in winter.  Not as narrow as summer, but still visibly different from the past.
Title: Re: The 2017/2018 freezing season
Post by: gerontocrat on December 31, 2017, 03:42:45 PM
I wonder how that might impact sea ice formation ?

I also wonder what it will mean for precipitation (snow) on the sea ice in the Pacific side of the Arctic? Last year, we saw what the train of Atlantic storms eventually meant for the melting season.
The cci-reanalyzer outlook for the next 5 days shows how there is lots of activity in the Bering Sea and the Atlantic end of the CAB, but the Arctic, most of N. America and most of Siberia are drize-a-bone.
It has been like that for some time. I am sure that so far snow accumulation (where data is available) would confirm this trend to date, e.g. goto (ffortran rules OK?) https://www.dmi.dk/en/groenland/maalinger/greenland-ice-sheet-surface-mass-budget/.

Every year is different - and how.

ps:- O mighty one, what will I post greenland surface mass stuff on on Jan 1 2018.

Title: Re: The 2017/2018 freezing season
Post by: Tor Bejnar on December 31, 2017, 03:44:53 PM
The 8 or 9K average temperature 'step change' (eyeballed difference between current winter average and graph's average line) occurred at the end of December 2015 on the DMI 80N chart (http://ocean.dmi.dk/arctic/meant80n.uk.php).  I don't recall anybody identifying a concurrent weather/climate change.  Did I miss the discussion or is this worthy of its own thread [maybe "DMI's 80N step change in winter temperatures" or "Step change in winter temperatures (e.g., DMI's 80N)"].  If so, someone with weather-cred should start such a thread, as they could better describe what appears to be happening ("climate" being '30-years' and we have 'two'.)
Title: Re: The 2017/2018 freezing season
Post by: Thomas Barlow on December 31, 2017, 05:05:07 PM
Yesterday - Lowest extent for date (and day) on record.

http://nsidc.org/arcticseaicenews/charctic-interactive-sea-ice-graph/
Title: Re: The 2017/2018 freezing season
Post by: Shared Humanity on December 31, 2017, 06:48:35 PM
Not quite sure how it would be quantified, but it looks to me like the DMI 80N is settling into a much narrower temperature band that it used to in winter.  Not as narrow as summer, but still visibly different from the past.

There certainly has been a trend of increasing temperatures, particularly in the fall over the past couple of decades but I had not noticed this reduction in range for a specific season. I decided to visually scan all of the years back to 1958 and came away with the sense that seasonal variation is all over the map. Would need to do a statistical analysis with the data to see if this is actually occurring.

The 8 or 9K average temperature 'step change' (eyeballed difference between current winter average and graph's average line) occurred at the end of December 2015 on the DMI 80N chart (http://ocean.dmi.dk/arctic/meant80n.uk.php).  I don't recall anybody identifying a concurrent weather/climate change.  Did I miss the discussion or is this worthy of its own thread [maybe "DMI's 80N step change in winter temperatures" or "Step change in winter temperatures (e.g., DMI's 80N)"].  If so, someone with weather-cred should start such a thread, as they could better describe what appears to be happening ("climate" being '30-years' and we have 'two'.)

2016 was certainly a wild year for temps but it could very well be an outlier as this year has fallen back to track more closely with years prior to 2016. Still very warm but not insanely so. No doubt, we are heading into uncharted territory.
Title: Re: The 2017/2018 freezing season
Post by: jdallen on December 31, 2017, 09:43:47 PM
I wonder how that might impact sea ice formation ?

I also wonder what it will mean for precipitation (snow) on the sea ice in the Pacific side of the Arctic? Last year, we saw what the train of Atlantic storms eventually meant for the melting season.
Indeed - that snow provided significant protection for the ice.

I think on the Pacific side, there is a very important difference - That snow is being deposited further south by 5-15 degrees of latitude.  It will start seeing warmer temperatures and significant sunlight earlier in the process and have longer to melt.  It will also have less time to thicken before the net energy balance shifts to where we have little to neutral heat exchange in that part of the Arctic.

Similarly, that snow is landing on ice which formed later, and which now will be further insulated from the remaining cold season.  I'm wondering if we will see large stretches of the Beaufort and Chukchi *starting* the melt season at less than 1.5 M thickness, possibly < 1. 

Time soon to start tracking albedo and estimating heat uptake vs radiative loss.

Put somewhat differently - favorable melt season temperatures and albedo won't be as much help if we start with significantly less ice in the first place.
Title: Re: The 2017/2018 freezing season
Post by: A-Team on December 31, 2017, 10:09:34 PM
Quote
The 8 or 9K average temperature 'step change' (eyeballed difference between current winter average and graph's average line) occurred at the end of December 2015 on the DMI 80N chart.
Interesting observation, Tor. The graphic below quantitates that by looking at the 'outer' two-thirds of the year via blue pixel counting that shows the mean temperature difference between 2017 and climate as 5.3ºC. We could name this Bejnar's anomalous fall-winter-spring warming effect (BAFWSWE) or maybe just stick with Arctic Amplification. (Additional years left to others; it's better to use ESRL's actual temperatures at the snow/ice surface for full Arctic Ocean.)

Cyclonic weather in the (shallow and nearly flat) Bering Sea will have the effect of mixing water to depth and so muting effects of cold air (if any); massive inflows into the Chukchi seen in June and this fall (earlier Mercator Ocean animation; mooring readings by R Woodgate) no doubt are contributing to the late freeze-up this winter.

The last 100 days of ASCAT show quite a bit of ice pack motion, including failure of the Beaufort Gyre to gyrate and a major resumption of Fram export about 70 days ago (inset in animation below).

As jdallen notes, the issue going forward is ice thickening. With half the freezing season gone, U Bremen SMOS is showing widespread peripheral areas of sub-half meter ice. While first year ice can potentially freeze to 2m thickness, that is not likely to be realized in these areas. (Some 79% of the ice pack is 1st year according to the Arctic Report card; multi-year ice is all but gone along the CAA and is no longer circling and thickening in the Canada Basin with the Gyre inoperative.)
Title: Re: The 2017/2018 freezing season
Post by: Alexander555 on December 31, 2017, 10:20:21 PM
The area where you see the big difference (red), how deep would the permafrost be in the ground at that location ?
Title: Re: The 2017/2018 freezing season
Post by: Dharma Rupa on December 31, 2017, 11:34:24 PM
The graphic below quantitates that by looking at the 'outer' two-thirds of the year via blue pixel counting that shows the mean temperature difference between 2017 and climate as 5.3ºC...
That is all well and good, but the range prior to this winter was indicative of a wildly unstable system, and suddenly we have a system which so far is looking very stable.
Title: Re: The 2017/2018 freezing season
Post by: A-Team on December 31, 2017, 11:44:42 PM
Here is the December 2017 late refreeze of open water in the Chukchi and Svalbard lee polynyas according to UH AMS2 at 3.125 km resolution. Other independent resources such as RASM-ESRL and SMOS show the residual open water a little differently, depending on how the earliest ice stages are treated (eg frazil, grease, nilas, congelation, pancake).

The inset salinities from Mercator Ocean show two dates (10 Sep 17 and 07 Jan18) at four depths (0, 34, 92, 318 m). These show the incredible intrusion of Atlantic Waters into the western Arctic Ocean, almost to the point they join up with Bering Sea intrusions. Some researchers now put oceanographic considerations on an equal footing with atmospheric effects in terms of causing sea ice loss.

Technical note: Mercator Ocean uses a different salinity scale at each depth and sometimes a different scale at different times for the same depth. They do not provide the underlying netCDF files that would allow users to pick a consistent scale or a perceptual palette, relying too much on canned graphics software called Leaflet. Note too that only surface oceanographic data has any prospects for satellite swath observation; the data is almost entirely modeled though in spots constrained to gliders, ship instruments, buoys and moorings.
Title: Re: The 2017/2018 freezing season
Post by: subgeometer on January 01, 2018, 02:37:52 AM
The 8 or 9K average temperature 'step change' (eyeballed difference between current winter average and graph's average line) occurred at the end of December 2015 on the DMI 80N chart (http://ocean.dmi.dk/arctic/meant80n.uk.php).  I don't recall anybody identifying a concurrent weather/climate change.  Did I miss the discussion or is this worthy of its own thread [maybe "DMI's 80N step change in winter temperatures" or "Step change in winter temperatures (e.g., DMI's 80N)"].  If so, someone with weather-cred should start such a thread, as they could better describe what appears to be happening ("climate" being '30-years' and we have 'two'.)

While the past 3 winters have made the change in conditions clear time will tell if dec 2015 is a stepchange or whether it constitutes our moment of recognition.If you look at the DMI charts there's a trend towards the new temperature band - you have to look before 2010 to find years where the temperature falls below the  average - I've included the chart for 2012
Title: Re: The 2017/2018 freezing season
Post by: subgeometer on January 01, 2018, 03:13:01 AM
The graphic below quantitates that by looking at the 'outer' two-thirds of the year via blue pixel counting that shows the mean temperature difference between 2017 and climate as 5.3ºC...
That is all well and good, but the range prior to this winter was indicative of a wildly unstable system, and suddenly we have a system which so far is looking very stable.

That's equivalent to the total FDD anomaly over those days, divided by their number. Nico Sun's FDD anomaly charts gives a way of comparing years. One interesting visualisation might be all the years of the DMI graphsoverlaid with the years in a colour gradient, say red for the most recent through yellow to green for the oldest

Title: Re: The 2017/2018 freezing season
Post by: Tor Bejnar on January 01, 2018, 04:52:08 AM
A-Teams 5.3K for 2/3rds of the year compares with my ~8-9K for 'winter' 1/4 yr. 

Reading what has been written above, I suggest we look at the 183 days (1/2 year) of 'functional winter' where the  DMI 80N green line (historic average) starting date and ending date have equal temperatures (vaguely day 293 to the next year's day 110).  I wonder what we might learn by comparing this evidence of 'Arctic amplification' with other evidence, such as FDDs (or FDD anomalies) and CAB ice volume.  (It appears that if the FDD anomalies chart started with day 110, the different years wouldn't show much deviation from the mean until after about day 240.  Of course, this is the period with the least recent difference between the DMI 80N green line and red line temperatures.)
Title: Re: The 2017/2018 freezing season
Post by: A-Team on January 01, 2018, 03:13:48 PM
My fervent hope for the New Year: people will kick their dependency on archaic proxies, regionally unaware line graphs, and redundant re-analyses to move on to newer and better observation-based resources.

Are people seriously not looking at Zack's twitter site? A lot of the graphics and data sourcing are done far better and quicker there than here, 80ºN and FDD below. The inset shows that the seriously off-center, single radiosonde-based 80ºN has no hope of representing Arctic sea ice developments. What does it know about inflows of Bering Sea water? https://twitter.com/ZLabe/media

So much just falls through the cracks here -- why? For example, Jim Hunt noted a much-improved resource on sea ice age a few days back. It sank like a stone. So did R Saldo's Sentinel 1AB winter animation of the Greenland Sea breakup that demonstrably undercut Piomas thickness. Want quantitative daily radiative fluxes ... it's sitting there at ESRL already animated for you. Indeed twenty new data resources are just a click away.

Alexander the Not-Yet-Great's dad could afford to hire Archimedes as the lad's personal math tutor. That accomplished very little because the kid expected to be shown the royal road to geometry. There isn't one.

And so it is with the search for the magical predictive proxy. That will prove futile. The Arctic is too complex an interacting system that is further undergoing rapid change. It won't work to carve out some tiny little piece, expecting it somehow to represent the whole.

The animation below shows an extension to 01 Oct 17 of the classical multi-year sea ice age product from NSIDC/Tsudi that stopped in Nov 2016. The new version, the subject of a clearly written, open source article still under review, is much more accurate.

A new tracking algorithm for sea ice age distribution estimation
AA Korosov et al
https://www.the-cryosphere-discuss.net/tc-2017-250/tc-2017-250.pdf

https://www.youtube.com/watch?v=c6jX9URzZWg
Title: Re: The 2017/2018 freezing season
Post by: Thomas Barlow on January 01, 2018, 04:37:12 PM
Lincoln Sea and Nares Straight -Jan 1
Title: Re: The 2017/2018 freezing season
Post by: Ice Shieldz on January 01, 2018, 10:32:20 PM
Thanks again A-Team. Did my best with the NSIDC/Tsudi sea ice age (SIA) animations you provided to create a mid October SIA yearly comparison starting at 2012. Shocking difference between 2016 to 2017!  Looks like the last bastion of old ice is near the middle of the CAB. Things don't seem to be boding well for the rest especially with the ongoing bloodletting out the Nares and with Fram export.
Title: Re: The 2017/2018 freezing season
Post by: A-Team on January 02, 2018, 05:11:55 PM
Quote
created a mid October SIA yearly comparison starting at 2012. Shocking difference between 2016 to 2017
Nice effort!  I have a request in for near-real time updating for the new sea ice age display (it's stuck on 01 Oct 17) and to fix existing glitches in their netCDF files (which go back to 01 Oct 12). These are much more interesting than indicated above. A log10 scale had to be used to bring out color since the ice age classes are so heavily weighted towards first year ice.

Sea ice age has an important byproduct in that its tracking involves accurate ice pack motion determination, now feasible year round in all weather via Sentinel-1AB. Thus ice age animation provide a vivid longterm depiction of bulk ice motion as well. First-year ice is easier to set in motion and to deform than older ice because it's much less massive and keels are shallower.

Sea ice age is strongly correlated with, but no substitute for, measured sea ice thickness. The latter is in troubled waters because of upward brine exclusion brings salinity to surface snow, confusing the satellites. Snow thickness itself is problematic because what might amount to ankle-deep accummulation then gets drifted about by the wind to local topographic lees.

The condition of the ice on January 1st for 2013-2018 is shown below for the Beaufort-Chukchi-Bering and Svalbard-Severnaya Zemlya regions (UH AMSR2 6.25 km resolution). This year is quite remarkable for the former region (as with the previous year) but not trending notably in the latter.

data sources:
ftp://ftp.nersc.no/ArcticData/esa_cci_sea_ice_age/
http://www.seaice.dk/
http://www.seaice.dk/movies/S1AB-LincolnSea-JanSep17/
ftp://ftp1.esrl.noaa.gov/RASM-ESRL/ModelOutput
https://manati.star.nesdis.noaa.gov/ascat_images/ascatB_ice_image/msfa-NHe-a-2018001.sir.gif
https://icdc.cen.uni-hamburg.de/thredds/catalog/ftpthredds/smos_sea_ice_thickness/v3/catalog.html
https://seaice.uni-bremen.de/data/smos/png/
ftp://ftp-projects.cen.uni-hamburg.de/seaice/AMSR2/3.125km/
https://www.giss.nasa.gov/tools/panoply/
Title: Re: The 2017/2018 freezing season
Post by: Thomas Barlow on January 02, 2018, 10:18:14 PM
You can hardly see it, so I marked it myself but 2018 is off to a really bad start.
Lowest extent for date (Jan. 1) on record (significantly lower)

You can roll over the point here to see it yourself:
http://nsidc.org/arcticseaicenews/charctic-interactive-sea-ice-graph/
Title: Re: The 2017/2018 freezing season
Post by: Brigantine on January 03, 2018, 12:57:10 AM
CIS is back online. Here's where the great lakes are up to according to them - 5th out of 38 seasons.

Following the GLERL data, 2018 is slightly lower on 19.7%, below 1981 and 1977, down to 7th out of 46 seasons.
Title: Re: The 2017/2018 freezing season
Post by: Neven on January 03, 2018, 10:20:10 AM
Warmest/Least coldest December on record for 65-90N:
Title: Re: The 2017/2018 freezing season
Post by: gerontocrat on January 03, 2018, 11:54:13 AM
On a post by A-Team he mentioned that bad weather in the Bering Sea would cause mixing of ocean water in the shallow seas there. So given the stormy weather outlook there, I had a look at the bathymetry.

The Bering Sea is a tale of two halves ( note that the Bathymetry scale is exponential).  If stormy weather persists surely sea ice formation will be impeded in the northern shallow region?


ps: Much of the East Siberian Sea is at a depth of less than 10 metres (methane thread?).

Images from:-

https://www.weather-forecast.com/maps/Alaska-United-States?over=pressure_arrows&symbols=cities.forecast.dots&type=wind
&
https://eos.org/project-updates/sounding-northern-seas
Title: Re: The 2017/2018 freezing season
Post by: Neven on January 03, 2018, 12:54:38 PM
Here are the surface temperatures for the four Arctic quadrants, all up from last year, except for Atlantic.

Ranking for this year (since 1948):

Atlantic 7th highest
Siberian 6th highest
Pacific 1st highest
Canadian 8th highest
Title: Re: The 2017/2018 freezing season
Post by: Neven on January 03, 2018, 10:48:08 PM
NH snow cover is also interesting right now:
Title: Re: The 2017/2018 freezing season
Post by: Dharma Rupa on January 04, 2018, 12:54:52 AM
NH snow cover is also interesting right now:
Down???

That is very interesting..., and I'm not sure of the correct way to take it.  Is there less humidity all of a sudden?
Title: Re: The 2017/2018 freezing season
Post by: Yuha on January 04, 2018, 01:41:16 AM
NH snow cover is also interesting right now:

According to Rutgers Snow Lab, Eastern Europe is the main area lacking snow.
Title: Re: The 2017/2018 freezing season
Post by: Neven on January 04, 2018, 09:03:14 AM
Indeed, the multisensor snow cover graph for Eurasia is even more explicit:
Title: Re: The 2017/2018 freezing season
Post by: Pavel on January 04, 2018, 09:14:55 AM
The lowest tracking sea ice extent, snow cover, and the warmest December in the Arctic. Looks interesting, but the long night still continue. I wonder how it will go when the sun will come back
Title: Re: The 2017/2018 freezing season
Post by: Paddy on January 04, 2018, 10:12:45 AM
NH snow cover is also interesting right now:

Interesting as in the old curse "may you live in interesting times" :-S

At least, on the positive side, there shouldn't be any direct link between E Europe snow in the region where it's less than normal and arctic sea ice.
Title: Re: The 2017/2018 freezing season
Post by: Neven on January 04, 2018, 10:24:11 AM
Interesting as in the old curse "may you live in interesting times" :-S

At least, on the positive side, there shouldn't be any direct link between E Europe snow in the region where it's less than normal and arctic sea ice.

Exactly, it doesn't mean much as of yet, although snow did play a significant part last year, IMO, in preventing record melt. And so it's just interesting, not 'interesting' (as in the old curse).

I can't wait to see the latest PIOMAS numbers.
Title: Re: The 2017/2018 freezing season
Post by: Ice Shieldz on January 04, 2018, 06:45:25 PM
Hmm wondering about snowfall on sea ice (not necessarily land masses) as that will reduce sea ice thickening during winter. With the high amounts of precipitable water north of 65N, i thought there could be a good bit of snow on the sea ice.

Below is 2017 Lincoln Sea & Nares export from January to September. This video, was previously provided by A-Team as link. I am trying to embed it here on ASIF (not sure exactly how to do that or how to embed youtube videos)

https://youtu.be/-3Jy6NRRmx0

Notice that from January-February 2017 the Lincoln Sea looses ice through the Nares and then stops between March-May, only to continue again though out the rest of the year.
Title: Re: The 2017/2018 freezing season
Post by: Neven on January 04, 2018, 06:52:19 PM
I am trying to it embed here on ASIF (not sure exactly how to do that or how to embed youtube videos)

Just post the link and it will automatically be converted, no tags required.
Title: Re: The 2017/2018 freezing season
Post by: magnamentis on January 04, 2018, 07:28:29 PM
NH snow cover is also interesting right now:
Down???

That is very interesting..., and I'm not sure of the correct way to take it.  Is there less humidity all of a sudden?

not less humidity but perhaps more rain instead of snow ?
Title: Re: The 2017/2018 freezing season
Post by: jdallen on January 05, 2018, 05:46:37 AM
NH snow cover is also interesting right now:
Down???

That is very interesting..., and I'm not sure of the correct way to take it.  Is there less humidity all of a sudden?

not less humidity but perhaps more rain instead of snow ?
Exactly my thoughts.  Cover may be down because cover may have been melted.
Title: Re: The 2017/2018 freezing season
Post by: Pmt111500 on January 05, 2018, 06:43:32 AM
Thanks for the Lincoln Sea Animation Ice Shieldz. That inspired me to go look if NASA still had the Worldview working, and I must say the 'compress scale'-feature on there is a great app. Night brightness T over Lincoln and High Nares. https://go.nasa.gov/2qra5MR and in case you get thrown to the unmodified scale adding the image (greenscale) (edit: oh, it looks like the shorthand link preserves the scale.) Note how the areas of clouds here show warmer brightness T than ice.
Title: Re: The 2017/2018 freezing season
Post by: gerontocrat on January 05, 2018, 02:22:17 PM
NH snow cover is also interesting right now:
Down???
That is very interesting..., and I'm not sure of the correct way to take it.  Is there less humidity all of a sudden?
not less humidity but perhaps more rain instead of snow ?
Exactly my thoughts.  Cover may be down because cover may have been melted.
I have been tracking precipitation on Greenland. Since the beginning of November it has been average or well below average. I look at cci-reanalyzer to see what the next few days may bring.

The two images below show what my feeble memory says has been the case for some time, to whit, lots of weather in the Northern Pacific leading into the Bering Sea and Strait and lots of weather in the North Atlantic leading right up to Novaya Zemla. In contrast, the CAB, most of Siberia and Mainland N. America has been and is and will be(?) DRY.

Trouble is, that while there is easily accessible data on Northern Hemisphere snow cover, I as yet have found nothing on snowfall amounts, i.e. thickness ( reminds one of sea ice thickness v. extent?).

My point is, even if snow cover extent is average but thickness is in inches rather than feet, it will disappear quicker as spring arrives ?
Title: Re: The 2017/2018 freezing season
Post by: Neven on January 05, 2018, 02:35:05 PM
Trouble is, that while there is easily accessible data on Northern Hemisphere snow cover, I as yet have found nothing on snowfall amounts, i.e. thickness ( reminds one of sea ice thickness v. extent?).

On the ASIG there's a NH snow depth departure (ie anomaly) map:

(https://www.ccin.ca/home/sites/default/files/snow/snow_tracker/plot_anom_sdep.png)

And a snow water equivalent map:

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fwww.ospo.noaa.gov%2Fdata%2Fmspps%2Fnn_images%2Fmhs_swe_des.gif&hash=fc161b5747ed3a224862fe171b262275)

I don't know how they are made or how trustworthy they are. I believe it's difficult for satellite sensors to track this, as with sea ice thickness, but for other reasons.
Title: Re: The 2017/2018 freezing season
Post by: gerontocrat on January 05, 2018, 03:06:30 PM
Trouble is, that while there is easily accessible data on Northern Hemisphere snow cover, I as yet have found nothing on snowfall amounts, i.e. thickness ( reminds one of sea ice thickness v. extent?).

On the ASIG there's a NH snow depth departure (ie anomaly) map:

And a snow water equivalent map:

I don't know how they are made or how trustworthy they are. I believe it's difficult for satellite sensors to track this, as with sea ice thickness, but for other reasons.

The images come from https://ccin.ca/home/ccw/snow/current   - Environment and Climate Change Canada Canada Snow Anomaly Tracking program

The methodology is described below - that includes a simple snow model as described in Brasnett (1999).

Quote
Data are derived from the operational global snow depth analysis run at the Canadian Meteorological Centre, Environment and Climate Change Canada Canada, since 1998. The CMC analysis is based on optimal interpolation of real-time climate station snow depth observations merged with background information from a simple snow model, as described in Brasnett (1999). This snapshot is a contribution to the Global Cryosphere Watch (GCW) programme of the World Meteorological Organization. (Brasnett, B. 1999. A global analysis of snow depth for numerical weather prediction, Journal of Applied Meteorology 38:726-740.)

There is other stuff e.g. a snow water equivalent graph that flatly contradicts my comment on the dryness of most areas prone to snowfall. Ho hum.
Title: Re: The 2017/2018 freezing season
Post by: prairiebotanist on January 05, 2018, 03:30:01 PM

Trouble is, that while there is easily accessible data on Northern Hemisphere snow cover, I as yet have found nothing on snowfall amounts, i.e. thickness ( reminds one of sea ice thickness v. extent?).

NOAA has the following, but, of course, that's only a fraction of North American snowpack: https://www.nohrsc.noaa.gov/snow_model/images/thumbnails/National/nsm_depth/201801/nsm_depth_2018010505_National_thumb.jpg 

Both ECMWF and GFS are hinting at a big warm-up in parts of E. North America in a couple weeks, so that might take a bite out of the snowpack there as well as undo some of the freeze up of the Great Lakes. https://www.tropicaltidbits.com/analysis/models/gfs/2018010506/gfs_T2m_us_51.png
Title: Re: The 2017/2018 freezing season
Post by: A-Team on January 05, 2018, 03:38:49 PM
Meanwhile, still some open water in the Chukchi on the 4th of January according to 3.125 km resolution UH AMSR2 (which is also seen in the U Bremen product, inset). Also a very small amount in the Beaufort but as pull-away polynyas rather than hasn't-yet-frozen.

Green indicates the extent of solid ice (100% concentration). Here the image will display at full height with a click without opening a new tab. Ice thickness is also rather meagre for this date though there's considerable annual variability, second image UH SMOS 03 Jan 18. The same date is available for 2011-2017 as both full scale animation (needs a click to animate today) and small scale all-in-one.
Title: Re: The 2017/2018 freezing season
Post by: subgeometer on January 06, 2018, 10:17:11 AM
The last few GFS runs on climate reanalyser are showing a succession of warm blasts coming in through Fram and over Greenland, the first in about 96 hours. Of course they can't be believed, but the one's  further out are successively more insane, with massive foehn winds bringing a huge area above freezing.

All the cold air is continually shunted into N America and Siberia
Title: Re: The 2017/2018 freezing season
Post by: aperson on January 06, 2018, 10:35:52 AM
Both GEFS and EPS ensembles are mostly in agreement on a synoptic setup that supports warm anomalies driven from subtropical advection on both the Atlantic and Pacific sides in the 5 day to 2 week mid range.

On the Pacific, a return of strong -EPO conditions starting around 5 days out will support another round of anomalies on the Pacific side. In the Atlantic, a strong pressure gradient along the NAO will transport subtropical moisture over the Greenland and Barents seas.

I've attached the 500hPa heights for GEFS and EPS in the mid range when both of these features are pronounced. The associated temperature anomalies for GEFS at this time are included as well. I would say these synoptic conditions have a very strong chance of verifying. The main question is what sort of duration each of these features will have.
Title: Re: The 2017/2018 freezing season
Post by: Shared Humanity on January 07, 2018, 05:17:38 PM
When Dr. Francis 1st made headlines here with her jet stream analysis and the resulting slide towards sticky weather patterns, I posted some very long comments regarding my concerns about the emerging sticky weather that, due to my nearly complete lack of scientific knowledge, was very speculative, depending solely on a very layman's perspective.

The 7 day forecast you have just posted has caused me to want to post a similar comment, actually a question for this community.

First, my assumptions:

Dr. Francis is correct. The rapidly warming Arctic is resulting in a slower, more elongated jet stream and this trend will continue. Sticky weather will be a result. I believe the recent research is supporting her argument.

My concern:

This sticky weather will not be random but, in fact, will have a stickiness to it that is a result of the jet streams interaction with the complex topography of the northern hemisphere. This is already the manner in which northern hemisphere climate and long term weather patterns occur, a very direct linkage between topography (oceans, continents etc.) and the atmosphere. We thus get persistent regional climates like the deserts of the southwest U.S., the temperate climate of the British Isles, the fantastic phenomena of tornado alley which I happen to live in and I believe is the result of an interplay between the Rocky Mountain, the Great Plains, a warm Gulf of Mexico and the jet stream. Essentially, our existing climate across the northern hemisphere already demonstrates vividly a stickiness which is due to the linkage between our topography and the atmosphere.

So, what are the major northern hemisphere topographical features? The Pacific and Atlantic Oceans, the North American Rockies and Great Plains, The vast Eurasian landmass, the Himalayas, the icy expanse of Greenland and until very recently, the persistent icy Arctic. There are others I am sure (Ooops, the Mediterranean Sea).

All of us are intimately familiar with the local climate of our region and the effect of the interaction between the atmosphere and local topography. The temperate rain forest climate of the Northwestern U.S. and the previously mentioned tornado alley for example.

Sorry for the long post but the forecast just posted, I believe, is evidence of an emerging sticky pattern, high pressure ridges that frequently set up over the North Pacific and over the North Atlantic and persist over long periods and are a direct result of an increasingly strong topographical influence over a weakening jet stream where the Pacific Ocean and the Rockies and the Atlantic Ocean and, perhaps, the icy landscape of Greenland will cause sticky patterns.

Arctic cyclone cannons anyone? How about more frequent and stronger U.S. East Coast bombogenesis Nor'Easters and the desertification of the U.S. Southwest?

As the jet stream weakens, would it not be the case that topography will have a stronger influence on weather and climate, essentially begin to dictate more thoroughly the weather and climate and impose a stickiness that a stronger jet stream would often but, now, less frequently overpower?
Title: Re: The 2017/2018 freezing season
Post by: aperson on January 07, 2018, 09:38:26 PM
I'm not a meteorologist just a weather weenie, but here's my take:

I think some of our climate teleconnections represent fundamental modes of oscillation in our atmosphere (ENSO, EPO, NAO, AO), and some of our other climate teleconnections are linearly dependent on these fundamental modes (PNA). These teleconnections themselves were found by performing principal component analysis on 500mb geopotential height anomalies to determine which empirical orthogonal functions explain the most variance among 500mb geopotential height patterns (see: http://www.cpc.ncep.noaa.gov/data/teledoc/telepatcalc.shtml). Our primary teleconnections are the ones that manage to explain a significant amount of the variance on a month-to-month basis, e.g. they commonly show up in the top 10 dimensions of PCA.

The question of "sticky" weather patterns then becomes a question of how the indexes for these (hopefully) orthogonal teleconnections evolve over time. Their random walks should essentially slow down if that's the case, or indexes should fall into zones of stability and instability instead of being normally distributed.

I know this doesn't give you answers, but it may help phrase the question you're trying to ask.
Title: Re: The 2017/2018 freezing season
Post by: subgeometer on January 07, 2018, 10:55:23 PM
The jetstream blows above a temperature contour on the surface - between cold/not cold or icy/melted, so as the winter temperature difference between the Arctic Ocean and the surrounding continents becomes greater with late refreeze, thin ice or none etc I expect to see more loops off the jetstream sheperding warm air into the basin. For now that should be most pronounced in the first half of winter while open water remains in the basin. Ie now the Chukchi Sea is frozen and as the Bering hopefully freezes perhaps the Pacific incursions will be less likely/extreme.

Edit: topography and the various climatic modes like AO etc obviously play a role as well

This is just a layman's take
Title: Re: The 2017/2018 freezing season
Post by: aperson on January 08, 2018, 06:51:21 AM
The -EPO and Strong NAO dipole patterns I mentioned earlier continue to be amplified on both GEFS and EPS ensembles. The resulting action of these creates a strong +DA (Dipole Anomaly) pattern that lasts from around τ=108 to τ=240 on the Jan 8 00z GEFS run. This pattern results in a substantial amount of warm air advection from the Eastern Pacific midlatitude region into the Arctic and across it toward the Atlantic side.

I have attached 500hPa height and anomaly plots at τ=168 as well as averaged temperature anomaly graphs across the aforementioned duration. I will be interested to see if this pattern continues to amplify. However, I suspect that we will still be at record low extent at the end of January because of the magnitude and duration of this torching event.

I have also noticed that reference EOFs for the +DA pattern are hard to find. They are available in Fig. 2 here: http://onlinelibrary.wiley.com/doi/10.1029/2008GL036706/full
Title: Re: The 2017/2018 freezing season
Post by: aperson on January 08, 2018, 09:33:59 AM
Given the strong MJO signal that is forcing the upper level jet to crash in the Central Pacific, I suspect that this pattern will be sticky once again.

I would put the over/under line for NSIDC Arctic Sea Ice Extent on Feb 1, 2018 at 13.4m km^2. And personally, I would take the under on this line.
Title: Re: The 2017/2018 freezing season
Post by: seaice.de on January 08, 2018, 07:09:37 PM
For those who have not seen this on Twitter: https://twitter.com/seaice_de/status/950023332015104001

Arctic sea ice apparent discrepancy resolved:



 Conclusion: thickness is the key for different metrics

(Click to start animation)
Title: Re: The 2017/2018 freezing season
Post by: A-Team on January 08, 2018, 07:29:42 PM
Nice. SMOS is probably the best single tool for monitoring progression of the freeze season. They don't provide any forecasts at this time though perhaps it could be integrated with NOAA's RASM-ESRL forty-frame ten days out when that resumes.

Just cross-posting to our automated script animation effort which is using PanoplyCL on daily UH SMOS netCDF files as its instance for range optimized display. The first post explains how to compare the same dates in various years via differencing map animations in Panoply, ImageJ or Gimp; the second how to optimize data to palette for visualizations.

https://tinyurl.com/yadgrfsq file repository
https://forum.arctic-sea-ice.net/index.php/topic,1259.msg138130.html#msg138130
https://forum.arctic-sea-ice.net/index.php/topic,1259.msg138256.html#msg138256
Title: Re: The 2017/2018 freezing season
Post by: Ice Shieldz on January 09, 2018, 07:08:01 AM
According to NOAA's NCEP/NCAR data 65N-90N December air temps at 1000mb set a new record, although seemingly not as much of a record as the 925mb temps illuminated in Neven's PIOMAS update: http://neven1.typepad.com/blog/2018/01/piomas-january-2018.html (http://neven1.typepad.com/blog/2018/01/piomas-january-2018.html)

https://www.esrl.noaa.gov/psd/cgi-bin/data/timeseries/timeseries1.pl (https://www.esrl.noaa.gov/psd/cgi-bin/data/timeseries/timeseries1.pl)
Title: Re: The 2017/2018 freezing season
Post by: subgeometer on January 09, 2018, 11:05:49 AM
According to NOAA's NCEP/NCAR data 65N-90N December air temps at 1000mb set a new record, although seemingly not as much of a record as the 925mb temps illuminated in Neven's PIOMAS update: http://neven1.typepad.com/blog/2018/01/piomas-january-2018.html (http://neven1.typepad.com/blog/2018/01/piomas-january-2018.html)

https://www.esrl.noaa.gov/psd/cgi-bin/data/timeseries/timeseries1.pl (https://www.esrl.noaa.gov/psd/cgi-bin/data/timeseries/timeseries1.pl)

This GFS reanalysis of december via climate reanalyser shows the ugly story of anomalies at surface level (click to animate)
Title: Re: The 2017/2018 freezing season
Post by: A-Team on January 09, 2018, 12:38:09 PM
Ice thinness on 08 Jan compared for the last 8 years; bulk ice salinity changes 01-07 Jan 2018. Both need a click-tab to display properly.

The available date range for UH SMOS is too short to speak about trends and anomalies but the last two years are showing considerably more thin ice for this late date in January than previous years, including the blow-out year 2012 (which is 2013 in January terms).

The issue of departure from climate normals is discussed in depth here:

https://forum.arctic-sea-ice.net/index.php/topic,2223.msg138433.html#msg138433
Title: Re: The 2017/2018 freezing season
Post by: Jim Hunt on January 10, 2018, 11:23:41 AM
The latest discussion paper from the Norwegian young sea ice expedition:

"CO2 flux over young and snow-covered Arctic sea ice in winter and spring (https://doi.org/10.5194/bg-2017-521)"

From the conclusions:

Quote
We measured CO2 fluxes along with sea ice and snow physical and chemical properties over first-year and young sea ice north of Svalbard in the  Arctic ice pack. Our results suggest that young thin snow-free ice, with or without frost flowers, is a source of atmospheric CO₂ due to the high pCO2 and salinity and relatively high sea ice temperature. Although the potential CO₂ flux through the sea-ice surface decreased due to the presence of snow, snow surface still presents a modest CO₂ source to the atmosphere for low snow density and shallow depth situations. The highest ice to air fluxes were observed over thin young sea ice formed in leads. During N-ICE2015 the ice pack was dynamic, and formation of open water was associated with storms, where new ice was formed. Open leads and storm periods were important for air-to-sea CO₂ fluxes (Fransson et al., 2017), due to undersaturation of the surface waters, while the subsequent ice growth in these leads becomes important for the ice-to-air CO₂ fluxes in winter due to the fact that the flux from young ice is an order of magnitude larger than from snow-covered first-year ice.

Amongst other things it also discusses the temperature and salinity profiles of Arctic sea ice snow cover:
Title: Re: The 2017/2018 freezing season
Post by: A-Team on January 11, 2018, 05:02:35 PM
Ice pack motion -- and Fram export -- really picked up this fall and has continued into January 2018. It's easy to see but difficult to describe ice pack motion.

The pack has gotten much more fluid as first and second year ice has come to predominate. Wind circulation drives ice motion but the coupling depends on roughness and ridges and is resisted by ice keels. Ice motion in turn controls surface oceanic currents (though not those at depth such was western bathymetric boundary currents).

Watching the 2007 ice age video, another two weeks of that weather around the minimal extent would have resulted in a total ice blowout. That failure mode, which is a major alternative to the drip drip drip of the trend line, would have been 'premature' in the sense that Arctic Amplification of the air and Atlantification and Beringification of the portal seas had not progressed to the extent seen today and so would not have been able to sustain fall open water. (The Arctic Ocean is far too warm to seriously freeze once its stratification is stirred up.)

The ice is currently being exported as two merged streams of the last thicker ice. However it's not easy to draw an ice envelope over a 10 Sept 17 satellite image that shows which ice will be exported (or be in export position) by 11 Jan 18.

The problem here from the AI perspective is that feature-tracking tools like SIFT work best on consecutive days. However they aren't able to follow an initial tracking point over a season because point features don't have stable signatures. Small regional features do, and at least to the eye, remain recognizable even as they rotate and deform.

However the eye of even the dumbest person is a whole lot better at seeing this than the smartest AI.

Thus the issue of 'virtual buoys' is unresolved. With the advent of all-season Sentinel-1AB and its daily tiling up at DTU, the data is there to track ice motion at high resolution (if you like large files). However the 'line integral' problem of upgrading daily movements to buoy-like drift tracks has not been resolved on a seasonal or multi-year time scales.

Technical note: I've belatedly noticed that ImageJ has far better features for processing huge series of daily satellite images than Gimp. These are buried in sub-sub-sub menus of the Image menu and have to do with tiling (called montage), re-layering, adding date labels in clean text from constituent file names, allowing very fast simultaneous processing steps on all layers such as adding arrows, adjusting global contrast, enhancing local contrast, and ability to save out in greatly reduced file size as forum-shareable mp4.

Indeed the single best way of scanning an animation is simply mousing the slider back and forth just in the stack window. Here you can see immediately whether a project has an prospects of going anywhere, prior to doing the many subsequent steps.

The old-fashioned scatterometer images of ASCAT works quite well for ice pack movement. Here we could care less about its careful instrumental calibration of σ0. A lot of researchers don't get this: when trying to draw out feature recognizability, the information is in there, but the originals are highly sub-optimal for that purpose, whether following on with eye or AI. Below, adaptive contrast enhancement is piled on top of a conventional histogram stretch. ASCAT comes as rgb but is actually grayscale; were it in color like Sentinel-2AB white-on-white, decorrelated channel stretching would apply.

The mp4 below runs from the Sept minimum up to yesterday ... the caption shows day-number rather than calendar date. The epoch converter site tabulates these. The default forum mp4 setting is no-loop but that can be changed under the stop-start arrow. However there is no way to add a final frame delay other than high multiplicity in the original gif stack. The controller can be hidden and mouse-down will play or pause. 'Open video in new tab' results in an obligatory download at least in Opera. Copy-overs of mp4 posted elsewhere does not work in the manner of pngs or gifs.

Here parent gif was 695 pixels wide but for some reason the mp4 is going slightly out of bounds. (But at least it is playing and scrollable!) The 121 day file is just 3 MB at 150% resizing and high quality mp4 export so 2-3 years of continouse ASCAT could be displayed here, more by cutting to every 2nd or 3rd day. Note the quality of single day frames remains better in gifs.

Enhancements have been very successful here in suppressing some of the weather noise and promoting longer term recognizability of features. There's no Beaufort Gyre nor Transarctic Drift in sight though some days the wind pattern needed for the BG will set up on nullschool for a few hours.

See also the blow-up of the rotating block of ice along the CAA over at
https://forum.arctic-sea-ice.net/index.php/topic,416.msg138526.html#msg138526
Title: Re: The 2017/2018 freezing season
Post by: A-Team on January 12, 2018, 02:50:11 AM
Here's a full year of ASCAT ice pack motion. Summer is a bit hard to follow because of atmospheric interference. Other than that, fascinating. It makes more sense to just compare fall to spring for various years so watch for that tomorrow. (And thx to a NOAA team for some timely help on file accessing side!)

Quote
Technical note: this is technically difficult to make because of the immense initial file size  prior to cropping down to the Arctic Ocean. Yet at the end, it is not a large file though not all web browsers seem able to display forum mp4. However download seems to work ok and can be viewed on your local movie player. Even Opera is showing an artifactual green stripe down the Fram that is not in the original file or its QuickTime representation. However a crop at the level of the original gif seems to cure this problem. Note the day-number is initially hidden under the inept controller.
Title: Re: The 2017/2018 freezing season
Post by: Tor Bejnar on January 12, 2018, 04:02:41 AM
Both at home and at work I cannot watch mp4s due to lack of software.
(It didn't keep me from posting one, taken by a coworker's cell phone!)
Note: this is an image of a not working mp4, not a clickable icon.)
Title: Re: The 2017/2018 freezing season
Post by: Ice Shieldz on January 12, 2018, 04:09:16 AM
Seems the way to make the forum play nice with embedding video is to upload the video to a youtube account and then paste the youtube video's 'share link' (not the embed link) straight into your forum message.
Title: Re: The 2017/2018 freezing season
Post by: subgeometer on January 12, 2018, 05:16:48 AM
The GFS is showing a storm passing just north of Svalbard which intensifies to 972hPa about 54hrs out and stays around that intensity for a day or so. It grows out of a pulse of moist warm air fired up by a low acting as a slingshot off the coast of Greenland
Title: Re: The 2017/2018 freezing season
Post by: aperson on January 12, 2018, 06:10:19 AM
The 500hPa gyre around Iceland is nuts. GFS has had the low pressure center of the system drop down as low as 926mb MSLP on recent runs which would put us on once-in-a-decade scales. That thing is going to have high uncertainty in intermediate range and isn't going to resolve cleanly until we're probably sub 36 hr out, but it's a real Arctic cyclone threat with the current synoptics. Sure would be nice to have more surface obs around that region so that our models would resolve better.

I also suspect that Rossby wavebreaks from the NAO dipole that it's driving are the source of the sudden stratospheric warming signal that's been showing up starting at the end of January on recent GFS runs.

On another note, GFS has also been showing multiple tropical systems forming in the Atlantic and EPAC (fortunately just phantom systems so far).
Title: Re: The 2017/2018 freezing season
Post by: Neven on January 12, 2018, 10:39:52 AM
Seems the way to make the forum play nice with embedding video is to upload the video to a youtube account and then paste the youtube video's 'share link' (not the embed link) straight into your forum message.

I changed a couple of things and installed a forum mod for mp4s to be attached and played. However, I can see/play some mp4 files, but not others. I don't know how to fix this.

But like A-Team says: you can always download them and view them locally.
Title: Re: The 2017/2018 freezing season
Post by: A-Team on January 12, 2018, 11:03:37 AM
Quote
I cannot watch mp4s due to lack of software.
No computer, no web browser other than the phone's?
Quote
upload the video to a youtube account and then paste the youtube video's 'share link' (not the embed link) straight into your forum message.
Are not youtubes restricted to fixed length x width proportions? That would not work too well given Arctic Ocean shape. Then there is Twitter but their software has major weirdness issues.

It seems like movie formats are still a total tower of babel, dozesn of them. I think the problem is the codecs and patent troll law firms.

Be great if everyone could see the movies. They are about the only way that year-long ice time series can be shown as the file sizes get out of hand with gifs. For example, downsizing the 361 year of ASCAT to a 150 pixel postage stamp still requires 8 MB as a gif, close to forum limits but with horrific loss of quality.

The left half of the png shows the save options I have within ImageJ. There are none within Gimp. The right half shows some online file format conversion options. These often fail to work as advertised.

The mp4's may upload ok to youtube though there's been complaints online about that not working. Can someone with an account give the full year Ascat a try here?
Title: Re: The 2017/2018 freezing season
Post by: aperson on January 12, 2018, 11:04:45 AM
More recent gfs runs don't have ptype mixing to rain as deep over the Arctic as subgeometer's attachment above. However, this cyclone looks like it's still going to be very deep and cause extreme issues for Fram ice due to wave action:

Title: Re: The 2017/2018 freezing season
Post by: A-Team on January 12, 2018, 12:49:52 PM
Quote
cyclone looks like it's still going to be very deep and cause extreme issues for Fram ice due to wave action
Here are Fram and Nares export the last two years, from the mid-September minimum until January 11th. Again, way too large as gifs. To best view, turn controller off, loop to on, hit play.
Title: Re: The 2017/2018 freezing season
Post by: Yuha on January 12, 2018, 01:21:49 PM
I had the same problem with the mp4s and the problem seems to be that it uses an older version of mp4 known as MPEG-4 Part 2:

https://en.wikipedia.org/wiki/MPEG-4_Part_2
 (https://en.wikipedia.org/wiki/MPEG-4_Part_2)
This is not supported on my browser but a newer version known as H.264 or MPEG-4 Part 10 or MPEG-4 AVC is:

https://en.wikipedia.org/wiki/H.264/MPEG-4_AVC
 (https://en.wikipedia.org/wiki/H.264/MPEG-4_AVC)
Below is one of A-Team's mp4s converted to the new format.
Title: Re: The 2017/2018 freezing season
Post by: Neven on January 12, 2018, 01:27:32 PM
Yuha's version is working for me! Thanks!
Title: Re: The 2017/2018 freezing season
Post by: oren on January 12, 2018, 01:40:08 PM
A-Team's mp4 are not viewable on my browser except by downloading, this new one is viewable directly.
Title: Re: The 2017/2018 freezing season
Post by: Tor Bejnar on January 12, 2018, 02:03:29 PM
I can download A-Team's recent mp4 (at least at work), but Yuha's doesn't work for me directly or via download!
Title: Re: The 2017/2018 freezing season
Post by: gerontocrat on January 12, 2018, 02:22:54 PM
Here are Fram and Nares export the last two years, from the mid-September minimum until January 11th. Again, way too large as gifs. To best view, turn controller off, loop to on, hit play.

Below the last frame as at 11 Jan.

HELP ! What does the colour coding mean ? (OK, I am having an off day).

If it means depth of ice then 2018 is looking sicker than 2017.
Title: Re: The 2017/2018 freezing season
Post by: A-Team on January 12, 2018, 04:10:37 PM
Quote
Yuha's doesn't work for me directly or via download!
Double ditto. Not compatible with Mac QuickTime Player.
Quote
HELP Ice looks sicker in 2017! What does the colour coding mean?
Nothing was intended other than binning the 256 grayscale colors into 16 arbitrary distinct colors (ie 8-bit to 4-bit) for purposes of possibly illustrating floe motion better. This was the most effective of the canned palettes in ImageJ. However now I see that it actually is a 'spectral' lookup table and so the colors do correspond to snow/ice surface dielectric ~ ice surface salinity ~ extent of brine exclusion ~ sea ice age ~ sea ice thickness. More or less, the more less the farther down the chain towards thickness.

In other words, the whiter grays tend to be older and thicker and so are shown more as reds and magenta. However to compare volume export, wipneus estimates that on Piomas forum; to compare years for the whole Arctic Ocean in January, SMOS is probably best.

Technical note: any 256-color palette -- and there are thousands of these used in climate science -- can be imported into ImageJ or Gimp. However, many dozens of palette formats are in use. Patent trolls don't sit on these but it is still a major nuisance to move color tables around because most software wants to be in RGB full color which is 24-bit rather than 8-bit. ImageJ is currently in ruins because of a bad update so an older version has to be used (which has no movie export of any kind!).

Of the five options for saving out video on my computer, only three of them would open on my computer. ImageJ itself cannot open mp4's it just saved! However it can open the file back up when the raw avi codec is used yielding, weirdly, a gif.

So it looks like .mov, .avi, and .mp4 are the most promising. Neven would have to enable attachment uploads and media playing for .avi and .mov to pursue this further.

I emailed some of these mp4's to myself as attachments and they ran fine. But that's not a good test because I use aapl Mail rather than the more common google gMail.

fram.mov
fram.wmv
Fram.flv
fram raw.avi
fram mpeg.mp4
Title: Re: The 2017/2018 freezing season
Post by: Yuha on January 12, 2018, 04:38:43 PM
Here's a one last try with the mp4 format, this time converting it using HandBrake, which is a popular open source video conversion tool.

HandBrake actually produces a file with the extension .m4v, which is Apple's version of .mp4. The HandBrake manual says that you can just change the extension to .mp4 but this might not work with QuickTime. I'm posting it with .mp4 since the forum does not allow .m4v. Neven, is it possible to add m4v to the allowed file types?
Title: Re: The 2017/2018 freezing season
Post by: A-Team on January 12, 2018, 04:44:20 PM
Quote
one last try with the mp4 format, this time converting it using HandBrake
Loads and plays for me on Opera and Chrome but oddly not Safari mac. Handbrake is at https://handbrake.fr/

Below, H.264 codec wants to put out a .mov but if I change that manually to .mp4 it seems to play ok but only loads as an attachment, does not play here. So I ran it by an online converter to get a legitimate mp4 that is playing for me at least. It has a modified controller that allows full screen display (which doesn't work for this postage stamp size image.) https://movtomp4.online/

Technical note: Something else that folks might find useful: if you can get the object into ImageJ, it has a very nice feature called montage that will make a single image of whatever rectangular dimensions you provide, for example 248 = 31 rows x 8 columns which takes better advantage of screen ratio. This is also the place to apply global contrast operations because you can test the effect on all the frames. It then offers un-montage which along with concatenate and combine, allows multi-years to be shown side-by-side.

The simple gif animation below shows ice thinness the other day, whole ocean and Fram/Nares views. The Beaufort, Chukchi and Svalbard areas still have significant areas of thin ice.(Unusual, not unusual, temporary, or not long even a time series to say -- a lot of known unknowns there.
Title: Re: The 2017/2018 freezing season
Post by: Yuha on January 12, 2018, 05:16:35 PM
if I change that manually to .mp4 it seems to play ok but only loads as an attachment, does not play here. So I ran it by an online converter to get a legitimate mp4 that is playing for me at least.

Exactly the same for me. The first file does not show but plays ok when downloaded. The second one works perfectly on both Firefox and Chromium.
Title: Re: The 2017/2018 freezing season
Post by: Neven on January 12, 2018, 05:47:44 PM
I've added .m4v, .avi and .mov to the list of allowed attachment files. I've changed settings in the Simple Audio Video Embedder mod so that .avi and .mov get played as well. .m4v wasn't in the list, so I'm not sure whether it will be played.
Title: Re: The 2017/2018 freezing season
Post by: Tor Bejnar on January 12, 2018, 06:57:30 PM
Yuha's Handbrake mp4 (Reply #597) works for me, too.  (Thanks, developers!)
Title: Re: The 2017/2018 freezing season
Post by: gerontocrat on January 12, 2018, 07:19:31 PM
Quote
HELP Ice looks sicker in 2017! What does the colour coding mean?
Nothing was intended other than binning the 256 grayscale colors into 16 arbitrary distinct colors for purposes of possibly illustrating floe motion better. However now I see that it actually is a 'spectral' lookup table and so the colors do correspond to snow/ice surface dielectric ~ ice surface salinity ~ extent of brine exclusion ~ sea ice age ~ sea ice thickness. More or less, the more less the farther down the chain towards thickness.

In other words, the whiter grays tend to be older and thicker and so are shown more as reds and magenta. However to compare volume export, wipneus estimates that on Piomas forum; to compare years for the whole Arctic Ocean in January, SMOS is probably best.

Thanks A-Team. At my age one needs all the reassurance one can get that the brain is still firing on a few neurons.

But it is necessary again to wait until early next month to get a feel for the direction of travel of volume where it matters - in the CAB, even if winter sea ice extent at the margins remains at a record low.
Title: Re: The 2017/2018 freezing season
Post by: FishOutofWater on January 12, 2018, 07:23:37 PM
By downloading I could watch the MP4 files on my Mac in Quicktime.

That video of the past year shows that there are no coherent large areas of old ice. It's like fragments of older rock in a breccia. Greenland and the CAA have no holdout areas. The last strongholds broke last summer as far as I can see.

Over the past year Pacific water has flowed into the Arctic ocean at an exceptionally high rate. I don't know if there are precise scientific measurements of the amounts but someone must have pretty good estimates. Alaska had a record warm December and the Bering sea inflow of Pacific water has continued into January.

We may have another cool cloudy summer and see no record low in September, but people should be paying attention to the shocking changes we have seen for the past 2 winters.
Title: Re: The 2017/2018 freezing season
Post by: romett1 on January 12, 2018, 07:41:25 PM
Ice pack motion -- and Fram export -- really picked up this fall and has continued into January 2018. It's easy to see but difficult to describe ice pack motion.


Here is Dec 28 - Jan 11 (Fram, Nares (some days are missing due to clouds)). Images: http://ocean.dmi.dk/arctic/morrisjessup.uk.php
Title: Re: The 2017/2018 freezing season
Post by: gerontocrat on January 12, 2018, 07:45:50 PM

Here is Dec 28 - Jan 11 (Fram, Nares (some days are missing due to clouds)). Images: http://ocean.dmi.dk/arctic/morrisjessup.uk.php
Is it possible to slow the damn thing down. My eyes feel like they've been strobed !
Title: Re: The 2017/2018 freezing season
Post by: A-Team on January 12, 2018, 07:48:13 PM
Quote
It's like fragments of older rock in a breccia.
Nice summary and an important distinction. Oren also made this point over at the Lincoln Sea collapse video. There's still ice forming in narrow leads and cold polynyas even in summer. So some of this ice is neither fish nor fowl in terms of FY, SYI or MYI. Overall, the latter two are more of a melange every year.

That has to be having some effect on thickness variation over short scales, shear strength, deformation, rafting, ridging, keeling, landfast dislodgement, and ice pack mobility. I don't immediately see how to put a trend number on it though.

Maybe turn our backyard wildlife cam on a screen animation? It has motion detection capability and only takes a shot when change exceeds a tunable threshold. Probably could emulate that by Gimp differencing histograms on an Ascat series though weather makes them noisy.
Title: Re: The 2017/2018 freezing season
Post by: romett1 on January 12, 2018, 07:54:35 PM

Here is Dec 28 - Jan 11 (Fram, Nares (some days are missing due to clouds)). Images: http://ocean.dmi.dk/arctic/morrisjessup.uk.php
Is it possible to slow the damn thing down. My eyes feel like they've been strobed !
I agree, made it 10 times slower.
Title: Re: The 2017/2018 freezing season
Post by: Yuha on January 12, 2018, 08:01:31 PM
I've added .m4v, .avi and .mov to the list of allowed attachment files. I've changed settings in the Simple Audio Video Embedder mod so that .avi and .mov get played as well. .m4v wasn't in the list, so I'm not sure whether it will be played.

Thanks, Neven!

To test it, here's the HandBrake m4v. It's the same file as the mp4 I posted earlier with only the file name extension changed.
Title: Re: The 2017/2018 freezing season
Post by: FishOutofWater on January 12, 2018, 09:08:15 PM
Follow up on Bering Strait inflow. There's a good preprint on the Uni. Wash. PSC web site.
http://psc.apl.washington.edu/HLD/Bstrait/BeringStraitDrivingMechanism2017.html

Last summer's cyclonic conditions favored westerly winds and low sea surface heights in the ESS. That increased Pacific water inflow through the Bering strait. This winter's storms moving into the Arctic ocean from the Pacific have also increased inflow which has been driven by strong southerly winds. This weather has also weakened the Beaufort gyre.

That implies that cold fresh water in the Beaufort gyre has been flowing through the CAA and Nares towards the Labrador sea as the gyre weakened and released stored fresh water.
Title: Re: The 2017/2018 freezing season
Post by: Neven on January 13, 2018, 12:32:29 AM
To test it, here's the HandBrake m4v. It's the same file as the mp4 I posted earlier with only the file name extension changed.

Works for me.   :)

Follow up on Bering Strait inflow. There's a good preprint on the Uni. Wash. PSC web site.
http://psc.apl.washington.edu/HLD/Bstrait/BeringStraitDrivingMechanism2017.html

Rebecca Woodgate (http://www.apl.washington.edu/people/profile.php?last=Woodgate&first=Rebecca) from the PSC would probably have info on this. I've had some contact with her back in 2012, asking whether ocean heat flux through Bering had been comparable to 2007, but no luck. I guess we'll have to wait 2-3 years until it's published in a paper.  ;)

Edit: that paper you link to, is actually co-authored by Woodgate. Sorry for replying without checking first.
Title: Re: The 2017/2018 freezing season
Post by: RunningChristo on January 13, 2018, 10:14:37 AM
With temps at +5.4C currently at Longyearbyen, Svalbard, buildup of any seaice at least at the western side of Svalbard, will have  hard time taking place!

www.yr.no/place/Norway/Svalbard/Longyearbyen/?sp

The risk for events like the slides taking place in februar 2017, are increasing by the hours. Pretty surreal this happening in the middle of  winter at those latitudes...
Title: Re: The 2017/2018 freezing season
Post by: oren on January 13, 2018, 02:56:09 PM
With temps at +5.4C currently at Longyearbyen, Svalbard, buildup of any seaice at least at the western side of Svalbard, will have  hard time taking place!

www.yr.no/place/Norway/Svalbard/Longyearbyen/?sp

The risk for events like the slides taking place in februar 2017, are increasing by the hours. Pretty surreal this happening in the middle of  winter at those latitudes...
At first I read your post as referring to the temp anomaly, then I realized this is the actual temp. With heavy rainfall. Surreal indeed.
Title: Re: The 2017/2018 freezing season
Post by: A-Team on January 13, 2018, 04:21:11 PM
Quote
actual temp. With heavy rainfall. Surreal
The freezing season is not going so well off Alaska either, 1st image and animation.

Quote
Rebecca Woodgate from the PSC would have info on this
Actually that paper, to the extent it deals with summers 2014-16, is somewhat passé given the rate of change in the Arctic.

More to the point is Woodgate's summer 2017 rent-a-cruise mooring retrievals. This is actually a detailed fascinating trip log that shows the dicey nature of oceanographic research. An entire year can be wasted because of biofouling of a seabed cable release mechanism, snagging of lines by passing trawlers, high seas during narrow operating windows, and malfunctions in data recorders.

Even though 3 Chukchi moorings make for a very sparse sample for 9 million sq km, they still represents a huge expensive effort. Actual daily data at depth is imperative though as only the ocean surface can be directly accessible to satellite. Profiling buoys don't hold their position nor operate for long. Beyond that, you are looking at long long runs of ungrounded model theories.

A big breakthrough though has come with new autonomous buoyancy gliders that can operate up and down a sawtooth depth range over a huge distances for six months or more untended, then surface and beam up their data like a satellite swath only with an extra dimension. (There's one down in the AO now but it hasn't yet reported.)

http://psc.apl.washington.edu/HLD/Bstrait/BeringStrait2017CruiseReport_Norseman2_22ndJuly2017witheventlog.pdf

"Key Preliminary results. As discussed below (p.67), the mooring data show some remarkable changes this year:

(i) a remarkably warm June 2017 (~ 3°C warmer than climatology);

(ii) remarkably early arrival of warm water in the strait in spring/summer 2017 (in hourly data, ~ 15 days earlier than in any prior recorded year and ~ 1 month earlier than the average)

(iii) very late departure of warm waters from the strait in late 2016 (in hourly data, more than 20 days later than any prior recorded year)

(iv) anomalously fresh waters in winter (~1 psu lower in winter, ~0.5 psu lower in the annual mean)

(v) a record maximum freshwater flux in 2016, of ~ 3500km3/yr (relative to 34.8 psu)

(vi) record high northward flows in fall 2016 (in 30-day smoothed data).

Key Statistics: 3 moorings recovered, 3 moorings deployed, 342 CTD casts on 19 CTD lines"

Meanwhile, on the thin ice front:

Warm Winter, Thin Ice?
Julienne Stroeve et al  review: 04 Jan 2018
https://www.the-cryosphere-discuss.net/tc-2017-287/tc-2017-287.pdf free fulll

Winter 2016/2017 saw record warmth over the Arctic Ocean, leading to the least amount of freezing degree days north of 70° N since at least 1979. The impact of this warmth was evaluated using model simulations from the Los Alamos sea-ice model (CICE) and CryoSat-2 thickness estimates from three different data providers.

While CICE simulations show a broad region of anomalously thin ice in April 2017 relative to the 2011–2017 mean, analysis of three CryoSat-2 products show more limited regions with thin ice and do not always agree with each other, both in magnitude and direction of thickness anomalies.

CICE is further used to diagnose feedback processes driving the observed anomalies, showing 11–13 cm reduced thermodynamic ice growth over the Arctic domain used in this study compared to the 2011–2017 mean, and dynamical contributions of +1 to +4 cm.

Finally, CICE model simulations from 1985–2017 indicate the negative feedback relationship between ice growth and winter air temperatures may be starting to weaken, showing decreased winter ice growth since 2012 as winter air temperatures have increased and the freeze-up has been further delayed.
Title: Re: The 2017/2018 freezing season
Post by: oren on January 13, 2018, 04:26:06 PM
Thank you A-Team, very interesting, especially the warm water departure and arrival timings.
Title: Re: The 2017/2018 freezing season
Post by: FishOutofWater on January 13, 2018, 07:49:51 PM
Yes, A-Team the Arctic is changing so rapidly that a paper submitted for publication is already getting long in the tooth.  Weather maps, sea surface height maps and sea ice concentration maps indicate that the inflow of Pacific water to the Arctic this fall and early winter is the highest ever measured. Southerly winds have been extreme as storm after storm has pushed up from the Pacific into the east Siberian sea. In December ice may be pushed through the Bering Strait, but there's close to zero heat content in the water. This December there was close to no ice and the water still had residual heat as it flowed into the Arctic. This is a first, as far as I know. I await the publication of inflow data for 2017-2018 to verify what I have been observing by looking at on-line maps and data sets.

The attached image for 23December17 shows an intense sea surface height gradient in the Bering sea driving Pacific water into the Arctic ocean. The extreme weather that caused this gradient also set off the chain of weather events that brought brutal cold to the U.S. east coast.

Title: Re: The 2017/2018 freezing season
Post by: FishOutofWater on January 13, 2018, 08:45:39 PM
Climatology for the 30 years upto 2010 was for Oct-Dec winds to blow from north to south in the Bering Strait region. Those winds helped build up the ice pack in the Bering sea. This year the southerly winds kept the ice from forming and were strong enough to push Pacific water and a some ocean heat into the Arctic.
Title: Re: The 2017/2018 freezing season
Post by: Alexander555 on January 13, 2018, 09:01:38 PM
Climatology for the 30 years upto 2010 was for Oct-Dec winds to blow from north to south in the Bering Strait region. Those winds helped build up the ice pack in the Bering sea. This year the southerly winds kept the ice from forming and were strong enough to push Pacific water and a some ocean heat into the Arctic.

I have been reading a few rapports that indicate that sea is also warming at deeper levels. I would say that this has an impact in several ways. Can you say something more about that ?
Title: Re: The 2017/2018 freezing season
Post by: Jim Hunt on January 13, 2018, 09:50:45 PM
There are currently two cyclones off Greenland causing some giant waves in the Fram Strait:

http://GreatWhiteCon.info/2018/01/the-january-2018-fram-strait-cyclones/

Amongst other things they've also generated severe weather warnings for both rain and avalanches on Svalbard.

This is in the middle of January.
Title: Re: The 2017/2018 freezing season
Post by: FishOutofWater on January 13, 2018, 10:22:50 PM
The Mercator Ocean model has very anomalous excess heat still present at 100m depth in the Chukchi sea. Deeper, the Beaufort gyre has been displaced towards Canada and warm salty water has moved into the west side of the gyre from the Atlantic along the Siberian shelf.

Heat has moved into the Arctic ocean from both the Atlantic and the Pacific. Last years cyclonic conditions favored deep Atlantic water inflow. The southerly winds in the Bering sea favored shallow (there is no deep) inflow from the Pacific.

The Jet Stream for December was really screwed up. It was intense on the east coasts of Asia and north America, but then weakened and tracked far north of normal in both the Pacific and Atlantic. This is probably the effect of a combination of La Niña, very warm waters on the east coasts of both continents (warming oceans) and a general weakening of the westerlies associated with a warming climate.

Note that with global warming the thermal contrast on the east coasts of Asia and N. America will stay strong while the contrasts weaken over the mid ocean. This will tend to create a jet stream that looks like it did this December.

It will also lead to ridiculously warm wet intense storms moving from the Atlantic towards the Arctic like the one hitting Svalbard now.

Title: Re: The 2017/2018 freezing season
Post by: FishOutofWater on January 13, 2018, 10:42:17 PM
There has been a considerable tightening of the subpolar gyre in the Labrador and Greenland seas. That indicates warm salty Gulf Stream water is spinning around and sinking on the shelf margins of Labrador and the south tip of Greenland. It may indicate more water heading towards the Arctic over the next few years. It's also the energy source for the intense storms coming over the next few days.
Title: Re: The 2017/2018 freezing season
Post by: Jim Hunt on January 13, 2018, 11:22:28 PM
Via Axel Schweiger on Twitter:

https://twitter.com/AxelSchweiger/status/952082493175316482

Quote
The Polar Science Center lost one of its founders: Alan Thorndike, inventor of the sea ice thickness distribution theory at the heart of many sea ice models.

http://psc.apl.uw.edu/psc-loses-one-of-our-founders-alan-thorndike/

Quote
Alan Thorndike died on Jan 8, 2018  from an aggressive pneumonia.  He was 72 years old.

RIP Alan.
Title: Re: The 2017/2018 freezing season
Post by: A-Team on January 14, 2018, 02:32:09 PM
Last year saw all these Atlantic clones bring warm wet weather up into the Arctic, accompanied by presumptions that this might be the new normal for the New Arctic. However 2017/18 so far is not going along with this idea.

The significance of these storms for the 2016/17 winter are reviewed in Stroeve 2018 using CryoSat2 and the above-mentioned ice thickness distribution fields.

Thorndike's influential work on this dates back to 1975 per gScholar search:

Quote
The thickness distribution of sea ice
AS Thorndike, DA Rothrock…
https://tinyurl.com/ydb2z3l3

The polar oceans contain sea ice of many thicknesses ranging from open water to
thick pressure ridges. Since many of the physical properties of the ice depend upon its
thickness, it is natural to expect its large-scale geophysical properties to depend on the
  Cited by 682

Simulating the ice‐thickness distribution in a coupled climate model
CM Bitz, MM Holland, AJ Weaver… - Journal of Geophysical …, 2001 - Wiley Online Library
… [1975] suggested a plausible b(h) might decrease linearly with the cumulative thickness
distribution up to some value G*. We adopt Thorndike et al.'s … 7(h•,h2)dh2, which describes the
increase in the concentration of ice in the interval (h2, h• + dh•) when a unit of ice of thick …
  Cited by 300

Estimates of sea ice thickness distribution using observations and theory
AS Thorndike - Journal of Geophysical Research: Oceans, 1992 - Wiley Online Library
Abstract The thickness distribution of sea ice is maintained by a balance of thermal and
mechanical processes. Observations now exist that make it possible to quantify this balance
and to test models of the individual physical processes. In particular, the observed
  Cited by 23


Influence of the sea ice thickness distribution on polar climate in CCSM3
MM Holland, CM Bitz, EC Hunke… - Journal of …, 2006 - journals.ametsoc.org
… Mechanical redistribution is parameterized following Rothrock (1975), Thorndike et al. (1975),
and Hibler (1980) … Figure 4 shows the simulated seasonal climatological Southern Hemisphere
ice thickness. The thick solid line shows the 10% concentration from SSM/I data …
  Cited by 206

Measuring the sea ice floe size distribution
DA Rothrock, AS Thorndike - Journal of Geophysical Research …, 1984 - Wiley Online Library
Abstract Sea ice is broken into floes whose diameters range from meters to a hundred
kilometers. This fragmentation affects the resistance of the ice cover to deformation and the
melting at floe sidewalls in summer. Floes are broken by waves and swell near the ice edge
  Cited by 142

Ridging and strength in modeling the thickness distribution of Arctic sea ice
GM Flato, WD Hibler - Journal of Geophysical Research …, 1995 - Wiley Online Library
… The transfer function, 13(hl, h2), defines the distribution of ridged ice thicknesses produced by
deformation of an area of thin ice. Thorndike et al. [ 1975] proposed that ice is ridged into a fixed
multiple C2 of its original thickness, namely, 1 [•(hl, h2) = •5(h 2-C2hl)•2 (16) …
  Cited by 214

Sea ice thickness distribution in Fram Strait
P Wadhams - Nature, 1983 - Springer
… Thorndike et at. 15 estimated that ice growing thermody- namically will reach a draft of 1m
(thickness 1.11 m) in late April after a growth period of 76 days … during the observation period,
ice within 100 km of the ice margin in the Pram Strait was mainly first-year ice, while ice in the …
  Cited by 86

The under‐ice thickness distribution of the Arctic Basin as recorded in 1958 and 1970
AS McLaren - Journal of Geophysical Research: Oceans, 1989 - Wiley Online Library
… open water [Thorndike et al. 1975]. Thickness distribution is basically the frequency of different
ice thicknesses arising from the spatial coverage of open water, thin ice, and thick ice. A particular
combination generally determines its degree of roughness (ie, the thicker and more …
  Cited by 92

Theory of the sea ice thickness distribution
https://arxiv.org/abs/1507.05198
S Toppaladoddi, JS Wettlaufer 22 Aug 2015

We use concepts from statistical physics to transform the original evolution equation for the sea ice thickness distribution g(h) due to Thorndike et al., (1975) into a Fokker-Planck like conservation law. The steady solution is g(h)=(q)hqe− h/H, where q and H are expressible in terms of moments over the transition probabilities between thickness categories. The solution exhibits the functional form used in observational fits and shows that for h≪1, g(h) is controlled by both thermodynamics and mechanics, whereas for h≫1 only mechanics controls g(h). Finally, we derive the underlying Langevin equation governing the dynamics of the ice thickness h, from which we predict the observed g(h). The genericity of our approach provides a framework for studying the geophysical scale structure of the ice pack using methods of broad relevance in statistical mechanics.
Title: Re: The 2017/2018 freezing season
Post by: Alexander555 on January 14, 2018, 03:04:31 PM
What are the boldest predictions for an ice free arctic ? A couple days ice free.
Title: Re: The 2017/2018 freezing season
Post by: Avalonian on January 14, 2018, 03:51:06 PM
What are the boldest predictions for an ice free arctic ? A couple days ice free.

My impression is that many people here (me included) believe that it's possible for any year from now on to become nominally ice-free; it just needs the 'perfect' combination of weather patterns. Even a repeat of 2007 might do it with the current state of the ice. When will it happen, though? We'd be guessing. As A-Team's just pointed out, our expectations of new consistent patterns keep getting flummoxed; at the moment, zero-day just isn't predictable, especially with the apparent negative feedback effect of cloudy summers.
Title: Re: The 2017/2018 freezing season
Post by: gerontocrat on January 14, 2018, 04:39:57 PM
What are the boldest predictions for an ice free arctic ? A couple days ice free.
Predictions, in my experience, are a sure path to self-humiliation.

BUT, we can say that since 2012 (the record low year),

- CO2 ppm has gone up by about 13 (= about another 4.5 % above pre-industrial levels), and will continue to significantly for a good few years yet (even in the best-case scenario), which means:-

- the oceans have not only got warmer but will continue to get warmer
(see image below and https://www.nodc.noaa.gov/OC5/3M_HEAT_CONTENT/ ),

- Global air temperatures are up significantly and will continue to rise for a good few years yet.

So, over time, there is only one way for sea ice - down. That has to be the long-term trend.

And one year there will be ideal conditions for melt - and that is far as I will go.
Title: Re: The 2017/2018 freezing season
Post by: Alexander555 on January 14, 2018, 05:41:08 PM
Sounds all realistic. What would be the result of having an ice free arctic for a week ? Probably a week long flow of water that is moving out of the arctic  in a significant warmer condition than what it is  today.
Title: Re: The 2017/2018 freezing season
Post by: Dharma Rupa on January 14, 2018, 06:13:40 PM
Sounds all realistic. What would be the result of having an ice free arctic for a week ? Probably a week long flow of water that is moving out of the arctic  in a significant warmer condition than what it is  today.

This conversation probably belongs elsewhere, but if the Arctic is without ice for a week at min then it probably means a cold and snowy following winter for most of the Northern Hemisphere.  There will be no polar vortex at all.
Title: Re: The 2017/2018 freezing season
Post by: A-Team on January 14, 2018, 06:26:37 PM
Quote
Allowed file types: gif, jpg, mpg, pdf, png, txt, jpeg, mp4, m4v, mov, avi
Build it and they will come!

Just some cross-posted images from a longer more technical post on issues in making a  simultaneous titanic 9-year daily ASCAT movie coming to a forum near you soon(?)

https://forum.arctic-sea-ice.net/index.php/topic,1259.msg138784.html#msg138784

(https://forum.arctic-sea-ice.net/index.php?action=dlattach;topic=1259.0;attach=95781;image)

(https://forum.arctic-sea-ice.net/index.php?action=dlattach;topic=1259.0;attach=95782;image)
Title: Re: The 2017/2018 freezing season
Post by: Alexander555 on January 14, 2018, 07:09:25 PM
Sounds all realistic. What would be the result of having an ice free arctic for a week ? Probably a week long flow of water that is moving out of the arctic  in a significant warmer condition than what it is  today.

This conversation probably belongs elsewhere, but if the Arctic is without ice for a week at min then it probably means a cold and snowy following winter for most of the Northern Hemisphere.  There will be no polar vortex at all.

Maybe, but lets take the gulf stream as an example. And just tell it if i'm wrong. I take the gulf stream because i think it's a circulation. But probably you will have the same influence at many places in some way. So lets assume that hotter than normal water moves out of the arctic for a week. Moving into warmer places. So that will probably make it warmer faster. So when it moves into the caribean sea and the gulf of Mexico. It's already warmer than normal. So probably it will also exit the gulf of Mexico warmer than it normaly is. So it will take more time to cool it down. So if you would take a point in the north, lets say where the temperature on average is 5° C. Than this point will probably move a little further north. You see what i want to say, there will just be more heat in the north. So in general i would think that these cold burst will get smaller in the long term. Maybe with some short term volatility.
Title: Re: The 2017/2018 freezing season
Post by: A-Team on January 14, 2018, 07:21:02 PM
Quote
it's possible for any year from now on to become nominally ice-free
It reminds me of the critters around here getting extirpated, like the elf owl, deer and jackrabbits. There's a long-term declining trend as the habitat deteriorates, upon which the usual wild swings of natural variation are superimposed.

The upswings don't much affect the trend nor lead to recovery but the downswings can be enough, when the trend has brought things low enough, for numbers to hit zero from which no recovery is possible. (There'll be an open wind fetch of 3395 km from Little Diomede to Longyearbyen.)

So while we're already getting significant regional effects from our current position on the trend line, I wouldn't be surprised to see an effectively complete blowout over the Sept 2018-2020 time frame.

However the loss of multi-year ice is preceding more rapidly than anyone envisioned (by export and translocation to kill zones), moving us on a parallel track, distinct from bad weather blow-ins and blow-outs, to essentially all FYI which already has consequences fairly similar to no ice.

So more thought from the scientific community should be probably allocated to what comes after that, though I expect mostly wait-n-see as previous modeling didn't worked out and it won't be any better in fast-moving uncharted territory (eg permafrost emissions).

Note nothing we post here affects the ice outcomes one way or another ... previous words of wisdom from Oren.
Title: Re: The 2017/2018 freezing season
Post by: Dharma Rupa on January 14, 2018, 08:13:22 PM
...So lets assume that hotter than normal water moves out of the arctic for a week. Moving into warmer places. So that will probably make it warmer faster. So when it moves into the caribean sea and the gulf of Mexico....

The cycle time for Atlantic Deepwater is on the order of thousands of years, and yes, in a few thousand years the water will come back to haunt us yet again, and the +.01 degree added warmth will cause havoc.

https://en.wikipedia.org/wiki/Thermohaline_circulation
Title: Re: The 2017/2018 freezing season
Post by: Jim Hunt on January 14, 2018, 08:49:59 PM
According to Environment Canada the southernmost of the two cyclones off Greenland was down to a MSLP of 942 hPa at 12:00 UTC:

http://GreatWhiteCon.info/2018/01/the-january-2018-fram-strait-cyclones/#Jan-14

Amongst other things it's sending a nice big swell over to us here in SW England. The west coast of Ireland is forecast to be 30 feet at 19 seconds overnight on Tuesday!
Title: Re: The 2017/2018 freezing season
Post by: Tor Bejnar on January 14, 2018, 10:08:00 PM
...
Note nothing we post here affects the ice outcomes one way or another ... previous words of wisdom from Oren.
What??!!  Are you guys saying all our 'hot air' has no effect?
Title: Re: The 2017/2018 freezing season
Post by: El Cid on January 14, 2018, 10:44:49 PM
Quote
it's possible for any year from now on to become nominally ice-free
So more thought from the scientific community should be probably allocated to what comes after that, though I expect mostly wait-n-see as previous modeling didn't worked out and it won't be any better in fast-moving uncharted territory (eg permafrost emissions).



Do you know of any useful recent modelling effort that has any chance of realistically forecasting NH midlatitude climate in a seasonally open-ice Arctic scenario (which we will most likely soon experience)?
Title: Re: The 2017/2018 freezing season
Post by: jdallen on January 14, 2018, 10:48:39 PM
According to Environment Canada the southernmost of the two cyclones off Greenland was down to a MSLP of 942 hPa at 12:00 UTC:
<snippage>
I've been browsing the various model runs for 500hpa on tropical tidbits, and they're very consistent.  There's a persistent trough that for the next few days is going to rapidly transport warmer mid-latitude air masses past NW Europe into the Barents/Kara and then into the central Arctic proper.  The longer term/less reliable (96 hours +) models have the trough oscillating back and forth across the N. Atlantic, but generally persisting with a deep flow from further south into NW Europe and the Atlantic front of the Arctic.

On the Pacific side the trough(s) are not quite as persistent, but are sending consistent flow into the Bering and Alaska proper, but with some transport of heat across to the Beaufort and Chukchi.  Between waves, heat and rain, we may actually see serious decreases in extent in the Barents between Svalbard and FJL.  Even though the "cyclone cannon" of 2016 and 2017 has slowed it's rate of fire, what we have now is plenty troublesome.

The counter-flow appears to be across the CAA into the Canadian shield on one side, and across Eastern Siberia on the other.  I anticipate another Arctic break out across the Eastern US, and eastern China and Japan may find themselves unusually chilly as well.

I expect we'll see little to no net increase in extent on either side of the Arctic basin proper, but modest increase in extent in the Baffin and Labrador seas, the Greenland sea (driven mostly by Fram export, and the Sea of Okhotsk.  Unfortunately, none of the increases here will be useful for overall ice health.

While the FDD deficit this year is much less troubling than last, it's still bad.  With the marginal seas still taking such a beating from weather I'm not sure the improvement will really do us much good.
Title: Re: The 2017/2018 freezing season
Post by: aperson on January 14, 2018, 11:00:09 PM
While the FDD deficit this year is much less troubling than last, it's still bad.  With the marginal seas still taking such a beating from weather I'm not sure the improvement will really do us much good.

I think it's important to note that this can be a poor metric when looking at the Arctic as a whole since what's going on at 80-90N may be pretty different from what's going on at 70-80N. FDD has fared reasonably well because we're mostly seeing strong EPO and NAO dipoles which result in low pressure centers near Alaska and Iceland. This causes air to advect from the Canadian side to the Siberian side and vice-versa, which keeps the center of the Arctic reasonably insulated compared to the surrounding region. It's also a reason that the anomalously cold regions are appearing on the Canadian and Siberian sides this year.
Title: Re: The 2017/2018 freezing season
Post by: Neven on January 14, 2018, 11:22:20 PM
Andrew Slater used to make a FDD graph for the entire Arctic Ocean (vs only 80N). I've asked Nico Sun, aka commenter Tealight, if it would be easy to make a 66N FDD chart as well for the last 10 years. I can't believe I haven't asked this before.  :-[

In the meantime, snowfall still relatively low on the Northern Hemisphere, still mainly because there's no snow in Europe (we finally received like 1-2 cm of snow today, here in Southeast Austria), but in parts of the US as well:
Title: Re: The 2017/2018 freezing season
Post by: Neven on January 14, 2018, 11:23:48 PM
PS Stay on topic, folks. No speculations or long-winded philosophies about long-term trends, models, Gulf Stream or our 'hot air'.
Title: Re: The 2017/2018 freezing season
Post by: aperson on January 14, 2018, 11:30:28 PM
Do you know of any useful recent modelling effort that has any chance of realistically forecasting NH midlatitude climate in a seasonally open-ice Arctic scenario (which we will most likely soon experience)?

In the spirit of staying on topic with this thread, I'll try to stick with teleconnections that have appeared this season. One of the major drivers of SIE stalls this season has been an enhanced East-Pacific ridge. This results in subtropical heat and moisture being advected up through the PNW or Canada instead of a strong zonal jet flow crossing over California.

This sort of behavior is tied to the heavy -EPO trend we have seen throughout December and parts of January, our anomalously low Bering/Chukchi SIE, and the drought/wildfire favoring mesoscale pattern over southern California. Essentially, ice cover along the Pacific and Atlantic sides "pushes" the jet stream further out. When ice is anomalously low, then the temperature gradient to drive the polar jet decreases and Rossby wavebreaks over the Pacific and Atlantic become increasingly likely.

The following reference discusses this phenomenon in the East Pacific:

Future loss of Arctic sea-ice cover could drive a substantial decrease in California’s rainfall: https://www.nature.com/articles/s41467-017-01907-4
Title: Re: The 2017/2018 freezing season
Post by: magnamentis on January 14, 2018, 11:31:41 PM
i don't think that anyone here believes he can alter development or in other words, write ice-history. what we do ist to learn to best read what's going on and there is nothing wrong to develop a best possible interpretation of what's going on. the sooner and the ore people know and are convinced about what going to happen the more people can prepare themselves and/or do something to reduce the possible consequences.

guessing and erring is like learning by doing and nothing is wrong with it while stating the obvious is sound nice and smart while it's nothing but that, the obvious and therefore is not a genuine achievement.

BTW i see one cyclonic front after another beating the arctic from both, the atlantic as well as the pacific side. at least i get this impression while following temp anomaly maps and wind maps.

if it's correct that all those storm fronts contain heat and humidity i cannot entirely understand who we can say that this pattern does not apply to this season. to me it looks very very similar like last season except that it's worse because both sides get battered while last year it was mostly the atlantic side.

i might overlook something like so often ;) but the i'm eagerly looking forward to all the replies that show me what that might be.
Title: Re: The 2017/2018 freezing season
Post by: Neven on January 14, 2018, 11:35:20 PM
According to Environment Canada the southernmost of the two cyclones off Greenland was down to a MSLP of 942 hPa at 12:00 UTC:

940 hPa now! With Iceland almost perfectly in the eye of the storm.

PS @ Magnamentis, my impression is that there's much less storms coming in all the way into the Arctic via the Atlantic this year, and thus much less snow as well as last year (Pacific I don't know).
Title: Re: The 2017/2018 freezing season
Post by: subgeometer on January 15, 2018, 01:16:46 AM
Andrew Slater used to make a FDD graph for the entire Arctic Ocean (vs only 80N). I've asked Nico Sun, aka commenter Tealight, if it would be easy to make a 66N FDD chart as well for the last 10 years. I can't believe I haven't asked this before.  :-[

In the meantime, snowfall still relatively low on the Northern Hemisphere, still mainly because there's no snow in Europe (we finally received like 1-2 cm of snow today, here in Southeast Austria), but in parts of the US as well:

GFS reanalysis maps from climate reanalyser - http://cci-reanalyzer.org/reanalysis/daily_maps/ -  give a value for daily temperature anomaly in the Arctic circle - that's a potential source for an FDD chart but one that maybe misleading because its really just the Arctic Ocean that is of interest. Extreme cold in northern Siberia and/or Canada can offset warm anomalies over the ice. If there was a way of masking out the surrounding landmasses and the north Atlantic that would be great
Title: Re: The 2017/2018 freezing season
Post by: FishOutofWater on January 15, 2018, 01:45:25 AM
Neven, this year to date has had strong flow into the Arctic from the Pacific and less in the Atlantic. The repeated Arctic outbreaks into the American east coast finally cranked up the storms in the Atlantic.  These deep north Atlantic lows will kick off a wave train in the jet stream, shifting the long wave pattern. Siberia will get colder than normal and high pressure will build in over the ESS.

A-Team's multiyear sequence reminded me that freezing season can get started late, like it did in January 2013 and still lead to recovery. The ice pack was in horrible shape after summer 2012 but it recovered. This year, however does not look like January 2013 when there was a strong sudden stratospheric warming followed by intense high pressure over the pole for the month of February. That huge dome of high pressure over the Arctic ocean in cold dark February was key to sea ice recovery because enormous amounts of heat radiated out to space under clear skies. The cloudy conditions we are seeing now are not good for recovery.
Title: Re: The 2017/2018 freezing season
Post by: binntho on January 15, 2018, 07:55:23 AM
In the meantime, snowfall still relatively low on the Northern Hemisphere, still mainly because there's no snow in Europe (we finally received like 1-2 cm of snow today, here in Southeast Austria), but in parts of the US as well:
Well, some parts of Europe have seen snow - and ridiculous amounts at that. The Italian and parts of the Swiss alps had record breaking snowfalls last week, with towns and ski resorts isolated for several days.
Title: Re: The 2017/2018 freezing season
Post by: El Cid on January 15, 2018, 08:23:35 AM
I dont think that these NH snow charts are very useful. Snow in E-Europe, or mid-USA does not matter, it melts in March quickly anyway. What does matter is snow on arctic ice - at least that is what last summer proved. If there is lots of snow on some thin ice it can still insulate it for quite a while and protect it long enough. However, if the thin arctic ice is not protected by much snow - then all bets are off for next summer. So we should know how much snow is on arctic ice, and as far as I know we dont know that
Title: Re: The 2017/2018 freezing season
Post by: bbr2314 on January 15, 2018, 08:36:19 AM
I dont think that these NH snow charts are very useful. Snow in E-Europe, or mid-USA does not matter, it melts in March quickly anyway. What does matter is snow on arctic ice - at least that is what last summer proved. If there is lots of snow on some thin ice it can still insulate it for quite a while and protect it long enough. However, if the thin arctic ice is not protected by much snow - then all bets are off for next summer. So we should know how much snow is on arctic ice, and as far as I know we dont know that
...this is very incorrect.

Snow in southern latitudes does a much better job of reflecting sunlight back into space and reducing overall heat anomalies vs. snow in sunless high-latitudes (that are probably covered anyways).

Additionally, snowfall over thin ice can do a better job of insulating heat underneath, paradoxically creating warmer conditions if heavy snows occur when initial refreeze completes.
Title: Re: The 2017/2018 freezing season
Post by: meddoc on January 15, 2018, 11:13:09 AM

...this is very incorrect.

Snow in southern latitudes does a much better job of reflecting sunlight back into space and reducing overall heat anomalies vs. snow in sunless high-latitudes (that are probably covered anyways).

Additionally, snowfall over thin ice can do a better job of insulating heat underneath, paradoxically creating warmer conditions if heavy snows occur when initial refreeze completes.

Yeah, then we should be heading into a Rebound Year according to ur Analysis.

All that snow and cold should have stayed inside the Arctic Fridge. But no, it is escaping into lower latitudes, where it will disappear and fast. Causing flash floods, inundations and a lot of erosion- not to mention wildlife damage.
Title: Re: The 2017/2018 freezing season
Post by: El Cid on January 15, 2018, 12:12:21 PM
I dont think that these NH snow charts are very useful.
...this is very incorrect.

Snow in southern latitudes does a much better job of reflecting sunlight back into space and reducing overall heat anomalies vs. snow in sunless high-latitudes (that are probably covered anyways).

Additionally, snowfall over thin ice can do a better job of insulating heat underneath, paradoxically creating warmer conditions if heavy snows occur when initial refreeze completes.

You might think that it is incorrect and you might be right, the Arctic is a mystery :).

However, as far as I remember, last summer's story of the arctic was exactly what I said: more open water during the previous freezing season led to more snowfalls in the Arctic, which created good insulation on the ice which made it very difficult to melt that ice during the summer. That is how we avoided new record lows last summer despite record ice extent/volume minimums during the 2016-17 winter season, after which many people thought that there would be a complete collapse.

That is why I believe that for the Arctic ice EU and USA snowcover does not matter much (although it does matter for NH winter weather),  what matters is how much snow is insulating the ice in the Arctic.
Title: Re: The 2017/2018 freezing season
Post by: Gray-Wolf on January 15, 2018, 04:19:54 PM
Last winter ( well early autumn?) saw W. Siberia receive it's winter total over the month of October. In the early noughties it was discovered that when a snow patch melts out it impacts up to 1,500km away so the snow over W.Siberia probably had a lot to do with the slow melt on the Atlantic side of the basin?
Not so this year.
Title: Re: The 2017/2018 freezing season
Post by: A-Team on January 15, 2018, 05:05:16 PM
Here are a couple of movies that seem to be working for Mac/Window users over at DevCorner. The first is a synchronized display of the last four freeze seasons, from the Sept minimum up to 13 Jan 18. It looks like it can be bumped to 9 years of ASCAT data without the file size getting out of bounds (as it does with our more familiar gif animations). Note occasional satellite glitches (missing days) have been replaced by duplications of flanking dates.

The second shows UB SMOS thin ice development just for this season. That could also easily be bumped to 2x2=4 years, which allows comparison of freezing stages. Note a few of the frames have substantial radio frequency interference (gray flashes).

Note the forum mp4 controller offers a full screen mode that may or may not be beneficial. Some people will do better downloading the file and viewing on their own player.

Thanks to member Dryland, we now have automated plucking of netCDF files from daily packages, imaging them as specified with PanoplyCL scripts, animating in ImageJ, and saving out as mov --> mp4 videos.

We are thus in position, between ImageJ's montage compositing tricks and PanoplyCL, to provide some unprecedented internet offerings of historic and current cryosphere conditions at very reasonable file size with relatively little future effort.
Title: Re: The 2017/2018 freezing season
Post by: Ice Shieldz on January 15, 2018, 07:47:08 PM
In addition to the snow, another big factor here is of course cloud cover. It appears be increasing during freezing season and potentially melting season too. Worst case scenario is more clouds along with less continental snow and more sea-ice-snow, followed by a melting season shift to less clouds and a rapid melting of snow. It may not matter that much if melting season clouds come to the rescue, the Arctic sea ice trend is clear. She's losing her winter power and, as others have indicated, the wimpy ice that's left does less and less to reverse any negative freezing season feedbacks at play.
Title: Re: The 2017/2018 freezing season
Post by: Jim Hunt on January 15, 2018, 08:41:01 PM
940 hPa now! With Iceland almost perfectly in the eye of the storm.

It looks have bottomed out at 939 hPa:

http://GreatWhiteCon.info/2018/01/the-january-2018-fram-strait-cyclones/#Jan-15



Title: Re: The 2017/2018 freezing season
Post by: jdallen on January 16, 2018, 04:59:50 AM

...this is very incorrect.

Snow in southern latitudes does a much better job of reflecting sunlight back into space and reducing overall heat anomalies vs. snow in sunless high-latitudes (that are probably covered anyways).

Additionally, snowfall over thin ice can do a better job of insulating heat underneath, paradoxically creating warmer conditions if heavy snows occur when initial refreeze completes.

Yeah, then we should be heading into a Rebound Year according to ur Analysis.

All that snow and cold should have stayed inside the Arctic Fridge. But no, it is escaping into lower latitudes, where it will disappear and fast. Causing flash floods, inundations and a lot of erosion- not to mention wildlife damage.
Snow isn't escaping, cold is, which effectively detonates on contact with moist air at the mid latitudes when the air masses collide.  There's still plenty of moisture of snow pack on the ice, as this chart below seems to indicate.  20-40CM is plenty of blanket to slow down heat transfer significantly.  That's equivalent to a 10CM thick wall filled with fiberglass insulation, more or less.

https://i0.wp.com/www.stirimeteo.com/wp-content/uploads/2018/01/Snow-depth-North-Hemisphere-2.gif

Also found this cool article studying thermal transfer through snow on ice in the Beaufort:

http://onlinelibrary.wiley.com/doi/10.1029/2000JC000409/abstract

Over all, average thermal conductivity  of snow pack on arctic ice is about half that of the ice beneath it.  QED/Rule of thumb would be - 40CM of snow slows down ice thickening about as much as 80CM of ice.

Now to find some of last year's snow thickness plots from around this time...
Title: Re: The 2017/2018 freezing season
Post by: A-Team on January 16, 2018, 03:41:05 PM
Quote
equivalent to a 10CM thick wall filled with fiberglass insulation, more or less.
If dry fluffy powder. But how does that stay in place given month after month of strong surface winds? More likely it will drift onto irregularities, leaving bare ice in some places and meter-thick snowdrifts on the lee of pressure ridges. There's only an even blanket of snow when viewed with 50 km x 50 km grid cell averaging. No one goes out there to measure snow transects Oct through May.

If rain on snow -- which we are seeing this week off Svalbard and likely off Alaska -- that will melt the snow entirely or form layers of weak ice within the 'snowpack'. The only recent extended winter in situ monitoring of the Arctic Ocean snow is N-ICE 2015. They documented warm moist air driven melt events as well as the effects of waves washing over the meagre freeboard of FYI-SYI.

For better or worse, comprehensive physical modeling programs like RASM-ESRL bake all this in to their near real-time daily state descriptions: snow, rain, water-ice-air heat equation transfer, wind, mid-latitude advection, high vs low clouds and up-and-down radiative energy transfers. Those netCDFs will resume 14 Feb 18.

Can we do better intuiting quantification?

Then there is bottom-line ice thickness observation by combined satellite altimetry and salinity. These have error issues in processing steps but are far better anchored in reality than pure models. (A snow-driven correction factor for Cryosat from upwardly extruded brine mentioned up-forum has not yet made papers like Stroeve 2018.)

Following the thinner ice on the periphery plus FDDAO for thermal thickening may be the best current guides to how the freeze season is going, as compared to recent years past. The peripheral seas are the last to freeze and the first to melt and so affect the core via ice mobility, long-fetch waves, and air moisture.

The second image below restricts the UH snow thinness product for 14 Jan 18 to ice between 0.25 and 1.25 m thick, which could be the Goldilocks range for tracking (in terms of intrinsic accuracy) in the post freeze-over winter. Open water in September can freeze to ~2m thickness by the end of winter so the deficit is of interest. (SMOS alone does not go out to that thickness.)

The third image shows the same date after the big melt summer of 2012 (which was followed by an unremarkable 2013 extent). The time series available is too short, relative to variation, for statistical trending. Further, later years might have used improved algorithms.

It's feasible also to use weekly or monthly averaging out of Panoply but ice acceleration this year in the western Beaufort means individual floes have moved on and their thickening isn't being followed. The bottom animation shows the last 30 days of motion, including a couple of feature trackers over a blowup of export to the Fram.

This is a very unfavorable pattern for retention of thicker remnant CAA ice which is getting stretched in two directions: into the warmer Chukchi and towards export.

These maps are only feasible to produce when a Geo2D thickness file within a netCDF bundle is provided to Panoply for range-picking (eg UH, not UB). Here ice <0.25 m is re-colored light blue (distinguishing it from open water) and ice >1.25m off-white in Gimp.

Technical note: it is feasible to replace the two bounding colors in Panoply continuum palettes with distinct colors from the ambient gradient. This would directly resolve situations where 0 and NaN conflict. The question really is whether long time series can be automated in Panoply (yes, see DevCorn) and wrapped in ImageJ to movies without invoking manual curation in Gimp (probably).

http://www.npolar.no/en/projects/n-ice2015.html
http://www.npolar.no/en/projects/n-ice2015.html
https://seaice.uni-bremen.de/data/smos/png/
https://icdc.cen.uni-hamburg.de/thredds/catalog/ftpthredds/smos_sea_ice_thickness/v3/catalog.html
Title: Re: The 2017/2018 freezing season
Post by: gerontocrat on January 16, 2018, 06:46:57 PM
Quote
equivalent to a 10CM thick wall filled with fiberglass insulation, more or less.
If dry fluffy powder.

The thermal conductivity of snow is highly variable, just one among all the other variables quoted by A-Team. Given the paucity of data (rightly often bemoaned by A-Team) those teams doing the modelling are right on the edge of doability. But more credit to them for giving it a go.
Title: Re: The 2017/2018 freezing season
Post by: Jim Hunt on January 16, 2018, 07:27:56 PM
Big Joe Bastardi was talking nonsense about the DMI >80N temperature graph on Twitter (https://twitter.com/BigJoeBastardi/status/952600131706245120).

I figured I'd show him the error of his ways using an FDD graph, only to discover that the data on the last few days of December had already disappeared from the DMI web site. An email to Denmark has resulted in the entire data set now being available for download in a UNIX style .tar archive, should anybody else be interested.

ftp://ftp.dmi.dk/plus80N_temperatureindex/plus80n_temperatureindex_1958_2017.tar (ftp://ftp.dmi.dk/plus80N_temperatureindex/plus80n_temperatureindex_1958_2017.tar)

DMI have asked me to point out that before using the data you should carefully read the enclosed documentation.
Title: Re: The 2017/2018 freezing season
Post by: Iain on January 17, 2018, 01:18:48 PM
Jim,

There was some discussion around FDDs this time last year in the 16/17 freezing thread.

From memory, the gist was that for any given temp difference between cold air and above-freezing seawater, the Ice thickness tends to a particular value.

The upshot was that the dT in the period immediately prior to onset of spring melting was the most important for thickness and summer survivability. FDDs at the onset of Autumn freezing made much less difference.
Title: Re: The 2017/2018 freezing season
Post by: A-Team on January 17, 2018, 04:30:52 PM
Dawn at Little Diomede yesterday (arrow). WorldView will be showing some of the Chukchi soon in its visible and IR channels. That may be soot in the lower left and center, third image.

The eastern Lincoln Sea area is being pulled apart by conflicting motions: rotation westward but eastward Fram export, animation. We've seen that many times before.

Two views of the Beaufort (thermal and radar brightness) emphasize different features, second image.

Technical note: NOAA AVHRR at DMI shows ice fractures better than higher resolution DTU Sentinel-1AB images, probably because open ice leads reveal water (or new ice) at a different temperature. The flip side is that heat escaping from opening ice can condense to 'black smoke' (fog) that obscures ice details. It then becomes difficult to disentangle the actual width of newly opening leads from the width of lead + black.

Arctic ice is sometimes treated as a viscous plastic which works well enough in describing ice pack motion at very low resolution but underlying this at higher resolution are rips in the fabric that are important heat vents but more difficult to model.
Title: Re: The 2017/2018 freezing season
Post by: Tor Bejnar on January 17, 2018, 04:51:31 PM
Re: Jim's FDD chart, earlier today.  I wonder if a graph of the rate of change of FDDs would show us when different years really differ.
Title: Re: The 2017/2018 freezing season
Post by: seaice.de on January 17, 2018, 08:46:53 PM
Arctic ice is sometimes treated as a viscous plastic which works well enough in describing ice pack motion at very low resolution but underlying this at higher resolution are rips in the fabric that are important heat vents but more difficult to model. [/size]

Well, not entirely true. Lead occurrence can successfully simulated with (elastic) viscous plastic rheology. But I agree, high resolution is important:

https://www.youtube.com/watch?v=4eInu8VIKTM (https://www.youtube.com/watch?v=4eInu8VIKTM)

http://onlinelibrary.wiley.com/doi/10.1002/2016GL068696/
Title: Re: The 2017/2018 freezing season
Post by: A-Team on January 18, 2018, 02:29:40 AM
Thanks, I had not come across this article! M Böttinger https://www.dkrz.de) can be credited for the remarkable animation -- we rarely see hillshading to represent a variable (here thickness) on these forums other than NASA SVS productions.

Although these are effective as scientific visualizations (especially the mp4 linked below), they lose frame by frame data. I myself don't plan to "Download dataset as tab-delimited text" because this is better distributed (like RASM-ESRL forecasts) as two Geo2D time series within a single netCDF that can be operationally combined within Panoply (for alternatives to hillshading).

The AWI announcement does not point to a follow-up animation -- four years have gone by -- nor to an actively maintained near-real time archive that covers the current freeze season. The UH sea ice concentration netCDF archives are up to date but not properly geo-tagged (in contrast to the SMOS archive).

While we can agree that 'improving previous resolution from 111 km to some 4 km' is an important advance, it is no longer state of the art, given 200x better resolution from the ~.020 km daily resolution of Sentinel-1AB composited by R Saldo at DTU.

However the question is, does this improved resolution already pick the low hanging fruit in terms of capturing significant heat loss and new ice formation, or do we need to include the many narrow width but very long extent leads? That issue is discussed in the 7 subsequent papers citing this 2016 publication, notably the 2018 paper at 1 km.

For a valid article link, Wiley wants 'abstract' or 'full' on the end of links, here since it open source:
http://onlinelibrary.wiley.com/doi/10.1002/2016GL068696/full

Sea ice leads in the Arctic Ocean: Model assessment, interannual variability and trends
Q. Wang, S. Danilov, T. Jung, L. Kaleschke, A. Wernecke 13 July 2016

https://tinyurl.com/ydh9nzsr AWI press release links to HD versions of youtube

1995-2004 MP4 29.8 MB   https://tinyurl.com/yd7rd9nb too big for forum
2005-2014 MP4 27.9 MB   https://tinyurl.com/yd4k9u4n too big for forum

Q. Wang et al: FESOM Arctic Ocean sea ice concentration and thickness 1995-2014, links to movies in mp4 format. PANGAEA, https://doi.org/10.1594/PANGAEA.860354
 
"Sea ice leads in the Arctic are important features that give rise to strong localized atmospheric heating; they provide the opportunity for vigorous biological primary production, and predicting leads may be of relevance for Arctic shipping. It is commonly believed that traditional sea ice models that employ elastic-viscous-plastic (EVP) rheologies are not capable of properly simulating sea ice deformation, including lead formation, and thus, new formulations for sea ice rheologies have been suggested.

Here we show that classical sea ice models have skill in simulating the spatial and temporal variation of lead area fraction in the Arctic when horizontal resolution is increased (here 4.5 km in the Arctic) and when numerical convergence in sea ice solvers is considered, which is frequently neglected.

...The scientists used a widely known theory, which describes the material qualities of the sea ice as an elastic-viscous-plastic medium. This was often criticised in recent years. But 'the new results show that the old theory for sea-ice physics still remains valid, if the calculation is performed with high accuracy'.

The model results are consistent with satellite remote sensing data and discussed in terms of variability and trends of Arctic sea ice leads. It is found, for example, that wintertime lead area fraction during the last three decades has not undergone significant trends.

Supplement: Northern Hemisphere sea ice from a Finite-Element Sea-Ice Ocean Model (FESOM) 4.5 km resolution simulation. Concentration is shown with color; thickness is shown with shading. A global 1 degree mesh is used, with the "Arctic Ocean" locally refined to 4.5 km. South of CAA and Fram Strait the resolution is not refined in this simulation. The animation indicates that the 4.5 km model resolution helps to represent the small scale sea ice features, although much higher resolution is required to fully resolve the ice leads.

Even in cold winters, more and more leads are forming due to wind and currents, which only adds up to a small amount of the total area, but is responsible for a large part of the growth in ice.'

Quote
A 4.5 km resolution Arctic Ocean simulation with the globalmulti-resolution model FESOM1.4
Q Wang et al  24 July 2017
https://www.geosci-model-dev-discuss.net/gmd-2017-136/gmd-2017-136.pdf

Quote
Scaling Properties of Arctic Sea Ice Deformation in a High-Resolution Viscous-Plastic Sea Ice Model and in Satellite Observations
N Hutter et al 8 January 2018

Sea ice models with the traditional viscous-plastic (VP) rheology and very small horizontal grid spacing can resolve leads and deformation rates localized along Linear Kinematic Features (LKF). In a 1-km pan-Arctic sea ice-ocean simulation, the small scale sea-ice deformations are evaluated with a scaling analysis in relation to satellite observations in the Central Arctic.... The agreement of the spatial scaling with satellite observations challenges previous results with VP models at coarser resolution, which did not reproduce the observed scaling. The temporal scaling analysis shows that the VP model, as configured in this 1-km simulation, does not fully resolve the intermittency of sea ice deformation that is observed in satellite data.

To summarize, our understanding of various Arctic Ocean ice physical processes is demonstrably improving, as is near-real time tracking of the current season, but the ability to make end-of-season or multi-year predictions is not advancing. We understand better what is happening (and why) but not what will happen in the future, other than trend lines.

The problem with unpredictability, given the phenomenon of Arctic amplification, is Arctic sea ice is a leading indicator -- indeed driver -- of global climate change. Lacking a solid foundation here, ambitious 'coupled' climate models are not in a position to reliably predict the future, notably because the onset and consequences of positive feedbacks from Arctic sea ice loss can't be anticipated.
Title: Re: The 2017/2018 freezing season
Post by: jdallen on January 18, 2018, 04:57:45 AM
The thermal conductivity of snow is highly variable, just one among all the other variables quoted by A-Team. Given the paucity of data (rightly often bemoaned by A-Team) those teams doing the modelling are right on the edge of doability. But more credit to them for giving it a go.
The Beaufort Sea study I referenced elsewhere came up with an averaged value of about .33, which generalized effect of drifting, compaction, etc.

The value for new snow (A-Team's "powder") is much lower - .071.  Even slab snow (which has compacted into sheets which resist blowing is lower at .29.  However, the extra I think accommodates what A-Team was driving at in his comments.

As I'm pondering ways to apply this to gridded data, I will have to fudge and will likely choose to err in favor of the effective measured coefficient, as it similarly summarizes widely varying conditions across the pack.

As imperfect as that is, If we can start from some sort of direct measurement I agree with A-Team that this would put estimation a step up from the models, however clever.
Title: Re: The 2017/2018 freezing season
Post by: jdallen on January 18, 2018, 05:12:14 AM
Dawn at Little Diomede yesterday (arrow). WorldView will be showing some of the Chukchi soon in its visible and IR channels. That may be soot in the lower left and center, third image.
Indeed, returning with effectively no ice in the Bering to keep albedo high and prevent heat uptake.

The exchange is still strongly postive outbound, but in a few weeks it will start to balance out, sooner if we continue to see moisture and heat inputs from further south into the Bering.

I'm wondering now if we may see exceptionally early opening of the Bering strait and Chukchi - possibly as early as late March.  I'm also wondering what consequences *that* could have on the ESS and Beaufort as a cascade.
Title: Re: The 2017/2018 freezing season
Post by: Jim Hunt on January 18, 2018, 09:52:43 AM
The Sea Ice Prediction Network post season report has just been released:

https://www.arcus.org/sipn/sea-ice-outlook/2017/post-season

Quote
It is important to note that NSIDC changed their averaging method this year such that the monthly mean sea ice extent is now the average of all the daily sea ice extent values rather than the sea ice extent derived from the monthly average sea ice concentration. As a result, sea ice extents are slightly lower than before (i.e. 2016 extent previously was 4.70 and now is 4.51 million square kilometers).

This year, the observed mean extent for the month of September was 4.80 million square kilometers with the new averaging method compared to 4.87 million square kilometers using the old method. This represents a September sea ice extent that was 1.6 million square kilometers below the average September extent for 1981–2010, but 1.23 million square kilometers above the record low in September 2012 and 300,000 square kilometers above that in 2016.
Title: Re: The 2017/2018 freezing season
Post by: numerobis on January 18, 2018, 03:51:51 PM
My experience of the snow on the sea ice is that you don’t get bare patches except where new ice formed (at a lead). There’s some undulation but it’s pretty flat. Snowmachines fly along at 120 km/h, which implies there’s little risk of a big bump.

It is definitely not light and fluffy. It’s hard and compacted; you cut it with a knife to build bricks for your igloo. The bricks are about 10cm thick, but provide sufficient insulation to live in while it’s -40C outside. I don’t know the R value.
Title: Re: The 2017/2018 freezing season
Post by: A-Team on January 18, 2018, 04:04:42 PM
Quote
not light and fluffy. It’s hard and compacted
Meaning little trapped air to provide insulation. It sounds like the corners of hexagonal plate snowflakes have broken off, leaving rounded cores that pack much tighter.

Quote
may see exceptionally early opening of Bering strait and Chukchi as early as late March with knock-on consequences for ESS and Beaufort.
Quite plausible. For mid-January, the peripheral freeze season seems weak (except for the central Laptev-ESS). The Beaufort still shows extensive regions of thin ice, though by tracking individual CAA floes frozen into its matrix, we know cold air at a fixed position there sees a rapidly moving target to thicken.

Very little can be learned about this region from FDD80º as parts of these seas are in a different weather regime 1400 km to the south of that parallel. Indeed even the reanalysis wind seems to have a so-so correlation with ice velocity, suggesting it is mostly guesswork or that Beaufort currents dominate because floes have been consistently moving westward for 117 days (since day 266 of 2017).

The velocity accelerates markedly up a swath from Banks Island to eastern Chukchi, reminiscent of ice getting caught up in the Fram. Indeed, export there resumed around the same date following a massive intrusive squeeze from the Kara. A slug of ice almost 600 km long has been exported, mostly off the Laptev/SZ but with some north of Morris Jesup streaming in. A streak develops leeward of the small island, Ostrov Ushakova. [Note FJL is mislabelled as SZ on the final frame.]

One has to wonder how the volume being exported over the last 50 days compares to that newly created (and retained) by ice thickening.
Title: Re: The 2017/2018 freezing season
Post by: jdallen on January 18, 2018, 09:57:55 PM
One has to wonder how the volume being exported over the last 50 days compares to that newly created (and retained) by ice thickening.
Your Kara ice intrusion animation speaks to that.  It's new ice which is displacing 2nd year+ ice in the CAB, quite definitively.
Title: Re: The 2017/2018 freezing season
Post by: gerontocrat on January 19, 2018, 12:22:31 PM
Suddenly a really cold spell in the northern Bering Sea and into the Chukchi ?
Title: Re: The 2017/2018 freezing season
Post by: A-Team on January 19, 2018, 01:49:10 PM
Quote
Kara ice intrusion volume being exported over the last 50 days?
The intrusion is not picked up by SMOS ice thinness or AMSR2 concentration but it's seen clearly (at much improved detail) in Sentinel-1AB. Overlaying a rescaled lat lon grid from Panoply and using an online grid cell calculator, the intrusion area works out to about 40,000 km^2. UH SMOS has a fairly large pole hole here but is showing the ice being displaced averaging maybe 1.4 m in thickness. So that would be roughly 56 cubic km of export. That would be 3.8% of wipneus' 2017-12-31 PIOMAS volume of 14,418. The event isn't over (see one day change of 8 km below) so it might worth doing this more carefully when it is.
Title: Re: The 2017/2018 freezing season
Post by: jdallen on January 19, 2018, 06:15:57 PM
Suddenly a really cold spell in the northern Bering Sea and into the Chukchi ?
From the looks of it, not really.

The satellites show a far amount of anchored pack ice along the Bering shore of Alaska, which explains some of the"blue", but actually mostly the image suggests mostly normal to warm temps over the Bering. 

Interior AK looks colder, but not over the water. 

The Chukchi looks slightly cooler, but doesn't exactly look like a cold snap.
Title: Re: The 2017/2018 freezing season
Post by: subgeometer on January 20, 2018, 01:14:21 AM
Suddenly a really cold spell in the northern Bering Sea and into the Chukchi ?
From the looks of it, not really.

The satellites show a far amount of anchored pack ice along the Bering shore of Alaska, which explains some of the"blue", but actually mostly the image suggests mostly normal to warm temps over the Bering. 

Interior AK looks colder, but not over the water. 

The Chukchi looks slightly cooler, but doesn't exactly look like a cold snap.

The GFS forecast has relatively cold conditions developing for a few daysover an area in the Basin south of a line from the ESS to the Mackenzie delta, as well as really cold in Alaska. But by about 60 hrs in the cold is being pushed out into the North Pacific, bypassing the Bering Sea, and by 120 hrs its all gone from everywhere but Alaska , pushed out by warm cloudy air from the Atlantic side which is anomolously warm all week.

The huge cold airmass that has developed over Siberia has also almost totally avoided going over any sea ice area, and is about to head south
Title: Re: The 2017/2018 freezing season
Post by: gerontocrat on January 20, 2018, 10:13:35 AM
WINTER 2017-18 SNOW

"Environment Canada" has data on snow at https://ccin.ca/home/ccw/snow/current  .

Below are (for the Northern hemisphere) -
- a map of extent and variations from average depth,
- snowfall extent graph,
- snowfall mass graph.

If nothing else the contrast between extent - below average, and mass - above average is consistent with a warming world with increasing precipitation predicted especially at higher latitudes.

What this means for the remainder of the freezing season and for the 2018 melting season I leave for others to say.
Title: Re: The 2017/2018 freezing season
Post by: Neven on January 20, 2018, 11:27:20 PM
The GFS forecast has relatively cold conditions developing for a few daysover an area in the Basin south of a line from the ESS to the Mackenzie delta, as well as really cold in Alaska. But by about 60 hrs in the cold is being pushed out into the North Pacific, bypassing the Bering Sea, and by 120 hrs its all gone from everywhere but Alaska , pushed out by warm cloudy air from the Atlantic side which is anomolously warm all week.

The huge cold airmass that has developed over Siberia has also almost totally avoided going over any sea ice area, and is about to head south

Climate Reanalyzer is now also offering mp4 videos of their forecasts, and given that this Forum now supports mp4, here's the temperature anomaly forecast for the coming 10 days (and look at all that global warming moving over to the US East Coast, right where President Trump wanted it; amazing, innit?  ;)):

http://pamola.um.maine.edu/wx_frames/gfs/arc-lea/t2anom/mp4/gfs_arc-lea_t2anom_2018-01-20-12z.mp4
Title: Re: The 2017/2018 freezing season
Post by: A-Team on January 21, 2018, 12:51:04 AM
Quote
Climate Reanalyzer is now also offering Forum-supported mp4 videos of their forecasts...
It just keeps getting better!

Here is a pair of high resolution Sentinel-1B separated in time by only 12 hours. It shows the lower tongue of that Kara ice intrusion. Note the ice rearranging itself like a jigsaw puzzle. There was an additional translational component, towards the Fram, which was removed by shifting the second image back up to the sub-central fixed point to which the residual motion is relative to.
Title: Re: The 2017/2018 freezing season
Post by: subgeometer on January 21, 2018, 02:15:28 AM
Thanks for the tip Neven
Title: Re: The 2017/2018 freezing season
Post by: subgeometer on January 21, 2018, 02:35:19 AM
Quote
Climate Reanalyzer is now also offering Forum-supported mp4 videos of their forecasts...
It just keeps getting better!

Here is a pair of high resolution Sentinel-1B separated in time by only 12 hours. It shows the lower tongue of that Kara ice intrusion. Note the ice rearranging itself like a jigsaw puzzle.

Very elastic pack. There's a lot of shatter lines like last winter where leads open effortlessly.

I agree with Gerontocrat that sometimes` the framerate could be a bit slower on these short sequence and comparisongifs. ImageMagick sets it with a delay setting (eg 'convert -delay 100 [input files] output.gif' - the value is in milliseconds) , with other software I don't know how. Its a matter of preference I guess, but the slower rate allows the eye to linger a little on each frame

I played with your file and found convert will change the framerate without apparent issues.

Don't take as a criticism, your work is setting the bar here

Your movies you posted play fine on Linux as well - with Firefox on Ubuntu anyway
Title: Re: The 2017/2018 freezing season
Post by: A-Team on January 21, 2018, 03:07:49 AM
Quote
Very elastic pack. lot of shatter lines
These irregular shear lines are not elastic deformations as those terms are defined at english language wiki or used in classical 19th century continuum mechanics. This ice is brittle. Features  like embedded MYI floes are not changing shape. What we are seeing is more like a crystal dislocation or diffusely distributed earthquake strike-slip faulting than a Glen's law smooth deformation of ice deep under Jakobshavn.

Elastic too is used very differently in physics; here kinetic energy was not conserved but went off entirely into frictional heat, nothing is left to drive a rebound. However viewed at the very much lower resolution of say Ascat, you can get away with a viscoelastic perspective (see up-forum).

The ice here is experiencing a torque because the wind is pushing harder on the inbound side of the Kara tongue. In response, ice is trying to rotate regionally. That's really problematic because it is caught up in the overall AO ice pack which is mightily constrained in an asymmetric basin (with respect to shape, the north pole and coriolis force) bounded by immovable islands. We see consequences of this all the time. The only really large scale rotation possible for the Arctic Ocean is about the so-called pole of inaccessibility. A favorable MSLP pressure pattern for driving this is not uncommon but not that persistent either.

Sentinel-1AB shows opening leads quite well (as bright white) but ridging and over-riding floes not at all since it's viewing almost straight down. Between these three processes, there's no day-to-day conservation of ice surface area even outside of melt season.

Thanks for the animation rate suggestion. I've added some additional frame rates to the 200ms one above, having no idea whether various web browser actually switch between the two frames at the advertised rate. These are 600ms, 1000ms and 2000ms.

Myself, I've come to the opinion that mousing ImageJ stacks offline is by far the best viewing option for climate science time series. (That would involve a download of the forum gif and opening in ImageJ freeware for your platform.) Mousing can be varied from fast to slow, notably for some interior subset of interest. Elsewhere on the screen, several Gimp playback windows could be looping more conventionally through the animation at various fixed speeds.

The other thing ImageJ does very well is montage all the frames at any combination of rows x columns (eg 360 frames as 24x15 or 30x12). This makes optimal use of rectangular monitor displays: you can see all the animation frames at once. Further, contrast improvements consistently affect all the frames in the montage. The result can be sliced and diced back into the animation stack.

ImageJ will also subset an animation or concatenate or combine several. Somehow someone got all this to happen in milliseconds whereas Gimp can take several minutes on high frame count products.
Title: Re: The 2017/2018 freezing season
Post by: oren on January 21, 2018, 08:26:57 AM
Thank you as usual A-Team. The GIFs refresh as advertised on my Windows Chrome browser. I think the 1000ms rate is useful for short animations such as this, and the 600ms is probably better for longer ones. 2000ms is too long, and 200ms usually too short.
Title: Re: The 2017/2018 freezing season
Post by: Tor Bejnar on January 21, 2018, 04:28:51 PM
oren speaks my mind.  (Quakerese for "I agree with oren.)
Title: Re: The 2017/2018 freezing season
Post by: A-Team on January 21, 2018, 05:54:58 PM
Thanks for the feedback!

Here is a 100 frame false color gif at 120ms with a 1200 ms pause at the end, Ascat to 20 Jan 2018. This uses the 'phase' color table at ImageJ. It simplifies quite a bit of detail present in the original but does ok at retaining features for purposes of tracking their movement over time. (ImageJ offers many tools for quantified tracking but each has a substantial learning curve.)

In addition to the huge pulse of Kara ice, look at the stretching out of the MYI floes as they get caught up in accelerating motion towards the Chukchi. Ice in the central Arctic most manages to stay put despite what is going on around it but ice 'SE' of the pole appears to thin out as it gets drawn into the Fram.

The Kara ice makes up about 4% of the surface of the Arctic Ocean proper on 20 Jan 2018. Should it be lumped with other FYI or tracked separately?

If this keeps up, the ice pack will be very damaged before we even get around to melt season.
Title: Re: The 2017/2018 freezing season
Post by: gerontocrat on January 21, 2018, 06:33:44 PM
These animations demonstrate so well that the Arctic ice pack is not a solid lump - the energy, the dynamic, the movement, even in 100 days are amazing.  It is a great pity that these animations are not part of what the general public gets to see as a rule.
Title: Re: The 2017/2018 freezing season
Post by: Tor Bejnar on January 21, 2018, 08:40:12 PM
A-Team's 100-day animation shows that, no matter how hard the little engine tries (that is: Nares Strait), it is no match for the big guy (Fram Strait).  Years ago I read that Nares export (when open) is about 10% of Fram's.
Title: Re: The 2017/2018 freezing season
Post by: 2phil4u on January 21, 2018, 08:59:45 PM
I dont think that the late refreeze of chucki is the problem.
The reason is, if you look for estimated temperatures till april, they will stay much below zero.
So if this area refreeze a little later, it will not melt the same, because thicker ice insulate, so for example if an area refreeze 2 weeks later at same condition, it wil lose more heat, so the melt should be less then two weaks earlyer, say only 10 days earlyer.
The hole problem is not the temperature or radiation in the arctic but the transposing heat effect of lower attitude.
The arctic itself has rather a negative feedback, you can see this when looking that after porr low ice minimums the next year is better, so it seems to overcompensate this in the winter.
This dont mean the ice is surviving forever, because there are other factors.
There is more heat around and because a surface that is is the middle gets much more impact from ouside.
Look at a little circle and think about an area,a ring surrinding.
This ring has a much larger surface, so if you take it mathematically, a circle with r=1 and a bigger circle with r=1,5.
Lets say the ring from r=1,5 to 1 has the number 1 and the inner circle has the number 0.
So the total circle is 2.25 larger (1.5*1.5) and this 1.25 lets say have the value 1 and the inner ring the value 0.
If you mix this the hole circle has 0.65 even you can compare it with Say N80 and N75.
So the extra energy is coming from a lot larger surface then the inner circle and this is the most import efffect in my opinion, the ice albedo and winter insulation is more or less not cooling the water at all, but keep it warm, but this effect, you can observe after poor ice years (more extend instead of keeping low or lower) is quite strong, resulting in not low records last year, this negative feedback is as stronger as you go north but all the extra heat from climate change is surrinding this negative feedback area with extra heat all the time.
Title: Re: The 2017/2018 freezing season
Post by: A-Team on January 22, 2018, 01:03:04 PM
Quote
Arctic ice pack is not a lump - the energy, dynamic, movement, even in 100 days are amazing
Endlessly fascinating to watch! We may be seeing an increase in ice mobility this January, as expected from the increasingly FYI composition of the ice pack and continuing thinness in the Beaufort-Chukchi.

Check out the 'lift-off' of the entire ice pack from the western CAA especially east of Banks Island as well as ill winds elsewhere pushing the top of the floe stringer south towards the Bering Strait. The animation runs forwards and backwards in time.

Other satellite products like AMSR2 and SMOS are 'missing out' on these events as they do not image individual floes and features, though there's some interest in the last three weeks of SMOS blur (bottom). Sea ice age would pick them up but seems to always lag by months. WorldView could pick up Bering Sea events provided it were not cloudy. The ice is on the move though there's no export through the Bering Strait at this time.
Title: Re: The 2017/2018 freezing season
Post by: meddoc on January 22, 2018, 01:16:24 PM
If this mobility keeps up- and why wouldn't it?-
 there won't be enough Ice left in September to cool down a Champagne Bottle.
Title: Re: The 2017/2018 freezing season
Post by: Sleepy on January 22, 2018, 01:37:09 PM
That's not a problem because Disneys version is outdated, Santa sacked all of us dwarfs in the 90s and moved to Rovaniemi, Finland.
https://santaclausoffice.com/story-santa-claus-office/ (https://santaclausoffice.com/story-santa-claus-office/)
Even the Danes gave up on their claim, that Santa lives on Greenland, in December.
https://www.dr.dk/nyheder/udland/groenlands-turistorganisation-opgiver-julemanden-finland-maa-gerne-faa-ham (https://www.dr.dk/nyheder/udland/groenlands-turistorganisation-opgiver-julemanden-finland-maa-gerne-faa-ham)
Title: Re: The 2017/2018 freezing season
Post by: meddoc on January 22, 2018, 02:59:55 PM
That's not a problem because Disneys version is outdated, Santa sacked all of us dwarfs in the 90s and moved to Rovaniemi, Finland.
https://santaclausoffice.com/story-santa-claus-office/ (https://santaclausoffice.com/story-santa-claus-office/)
Even the Danes gave up on their claim, that Santa lives on Greenland, in December.
https://www.dr.dk/nyheder/udland/groenlands-turistorganisation-opgiver-julemanden-finland-maa-gerne-faa-ham (https://www.dr.dk/nyheder/udland/groenlands-turistorganisation-opgiver-julemanden-finland-maa-gerne-faa-ham)

Yes the climatological NP is being tossed into Siberia these Days. & partly Greenland.

http://cci-reanalyzer.org/wx/DailySummary/#t2anom
Title: Re: The 2017/2018 freezing season
Post by: Lord M Vader on January 22, 2018, 05:33:47 PM
NSIDC came back today after not updating yesterday. The most recent numbers reveals that 2018 sea ice extent is now the lowest on record, 30K below 2017. I shouldn't be too surprised if we'll continue to be lowest on record for at least a couple of days, or maybe the rest of the month.
Title: Re: The 2017/2018 freezing season
Post by: gerontocrat on January 22, 2018, 05:55:51 PM
That 30k difference is the 5day number? Daily extent spreadsheet says 2018 150k below 2017.0
Title: Re: The 2017/2018 freezing season
Post by: Lord M Vader on January 22, 2018, 07:40:01 PM
Gerontocrat: exactly! The 5-day average is better as it removes daily variations. But daily numbers are ofc of interest too :)
Title: Re: The 2017/2018 freezing season
Post by: gerontocrat on January 22, 2018, 08:03:12 PM
Gerontocrat: exactly! The 5-day average is better as it removes daily variations. But daily numbers are of interest too :)

I am in two minds about the 5 day versus 1 day question. Jaxa data (to confuse things more) is the two day average (?) and at the moment is showing a far more dramatic divergence in SIE between 2017 and 2018. 2018 is shown as 297 k less than 2017, about one week's average gain at this time of year.

Is some of this difference (and that JAXA SIE is always lower than NSIDC's figure) due to NSIDC data including places (such as Baltic, Okhotsk Sea?) that JAXA ignores?

But after a week or so the picture will become clearer.
Title: Re: The 2017/2018 freezing season
Post by: oren on January 22, 2018, 09:06:45 PM
JAXA data shows less extent thanks to its much better resolution.
Title: Re: The 2017/2018 freezing season
Post by: Paddy on January 23, 2018, 04:08:23 PM
Comparing current concentration maps to the forecast temperatures, do we or do we not expect the ice to play a bit of catch up over the next few days in the Barents / Bering / Okhotsk?

Jan 22nd Bremen concentration map:

(https://seaice.uni-bremen.de/data/amsr2/today/Arctic_AMSR2_nic.png)

Jan 24th ClimateReanalyzer forecast surface air temperature:

(https://keytwist.net/floe/external/t2/08.png/)

Jan 25th ClimateReanalyzer forecast:

(https://keytwist.net/floe/external/t2/16.png/)

Jan 26th ClimateReanalyzer forecast:

(https://keytwist.net/floe/external/t2/24.png/)

Further forecasts: https://sites.google.com/site/arcticseaicegraphs/forecasts2

I'm thinking potentially yes in all three, but what do I know?
Title: Re: The 2017/2018 freezing season
Post by: Stephen on January 24, 2018, 05:36:23 AM
Waaay back when I first got interested in climate chaneg science I recall the following as proof of global warming when caused by an intensifying greenhouse effect.


But then I got fascinated by the dramatic sea-ice decline of 2007 and 2012 and forgot about those fundamental proofs.

In my opinion a record hot summer temperate is more exciting but less significant than a record warm winter.  So I am thinking that these record low winter extents may be more significant than record low summer extents.  Not nearly as exciting - sure - there won't be any headlines in the NY Times.  But I am now follwoing  these winter extents with the same fascination I used to follow the summer extents.
Title: Re: The 2017/2018 freezing season
Post by: Daniel B. on January 24, 2018, 05:08:55 PM
Waaay back when I first got interested in climate chaneg science I recall the following as proof of global warming when caused by an intensifying greenhouse effect.

  • the nights will warm faster than the days
  • the winters will warm faster than the summers
  • the poles will warm faster than the equatorial regions

But then I got fascinated by the dramatic sea-ice decline of 2007 and 2012 and forgot about those fundamental proofs.

In my opinion a record hot summer temperate is more exciting but less significant than a record warm winter.  So I am thinking that these record low winter extents may be more significant than record low summer extents.  Not nearly as exciting - sure - there won't be any headlines in the NY Times.  But I am now follwoing  these winter extents with the same fascination I used to follow the summer extents.

I agree.  This is due to the increased cloudiness, which leads to warming in all seasons, but the summer.  See the following presentation:

https://atmos.washington.edu/~rmeast/BarrowPresI.pdf
Title: Re: The 2017/2018 freezing season
Post by: magnamentis on January 24, 2018, 10:52:27 PM
Waaay back when I first got interested in climate chaneg science I recall the following as proof of global warming when caused by an intensifying greenhouse effect.

  • the nights will warm faster than the days
  • the winters will warm faster than the summers
  • the poles will warm faster than the equatorial regions

But then I got fascinated by the dramatic sea-ice decline of 2007 and 2012 and forgot about those fundamental proofs.

In my opinion a record hot summer temperate is more exciting but less significant than a record warm winter.  So I am thinking that these record low winter extents may be more significant than record low summer extents.  Not nearly as exciting - sure - there won't be any headlines in the NY Times.  But I am now follwoing  these winter extents with the same fascination I used to follow the summer extents.

you name it, not much else to add, should be bookmarked and posted on each page once the summer discussions about minima are in full swing ;)
Title: Re: The 2017/2018 freezing season
Post by: Dharma Rupa on January 24, 2018, 11:26:08 PM
Waaay back when I first got interested in climate chaneg science I recall the following as proof of global warming when caused by an intensifying greenhouse effect.

  • the nights will warm faster than the days
  • the winters will warm faster than the summers
  • the poles will warm faster than the equatorial regions

But then I got fascinated by the dramatic sea-ice decline of 2007 and 2012 and forgot about those fundamental proofs.

In my opinion a record hot summer temperate is more exciting but less significant than a record warm winter.  So I am thinking that these record low winter extents may be more significant than record low summer extents.  Not nearly as exciting - sure - there won't be any headlines in the NY Times.  But I am now follwoing  these winter extents with the same fascination I used to follow the summer extents.

you name it, not much else to add, should be bookmarked and posted on each page once the summer discussions about minimal are in full swing ;)

Does seem that for those of us here this time of year he is preaching to the choir.

I can only add that all of this is because the major greenhouse gas is H2O.
Title: Re: The 2017/2018 freezing season
Post by: Ravenken on January 25, 2018, 12:58:05 AM
Waaay back when I first got interested in climate chaneg science I recall the following as proof of global warming when caused by an intensifying greenhouse effect.

  • the nights will warm faster than the days
  • the winters will warm faster than the summers
  • the poles will warm faster than the equatorial regions

But then I got fascinated by the dramatic sea-ice decline of 2007 and 2012 and forgot about those fundamental proofs.

In my opinion a record hot summer temperate is more exciting but less significant than a record warm winter.  So I am thinking that these record low winter extents may be more significant than record low summer extents.  Not nearly as exciting - sure - there won't be any headlines in the NY Times.  But I am now follwoing  these winter extents with the same fascination I used to follow the summer extents.

you name it, not much else to add, should be bookmarked and posted on each page once the summer discussions about minimal are in full swing ;)

Does seem that for those of us here this time of year he is preaching to the choir.

I can only add that all of this is because the major greenhouse gas is H2O.

And the more CO2/GHGs, the more H2O. Feedbacks suck.
Title: Re: The 2017/2018 freezing season
Post by: Paddy on January 25, 2018, 05:24:13 AM
At least if we do get more clouds it should reduce the impact of lost albedo from ice, right? (Although I've no idea how the numbers stack up on this)
Title: Re: The 2017/2018 freezing season
Post by: Ice Shieldz on January 25, 2018, 12:10:58 PM
Lincoln Sea Nares Export from 2017-12-24 to 2018-1-24. One tracked section of ice traveled approximately 115 miles (185km) in 31 days.  Furthest travel in one day was approximately 12 miles (19.3km).
Title: Re: The 2017/2018 freezing season
Post by: Daniel B. on January 25, 2018, 03:49:36 PM
At least if we do get more clouds it should reduce the impact of lost albedo from ice, right? (Although I've no idea of how the nkmbers stack up on this)

Yes, increased cloudiness will offset albedo losses due to decreased sea ice in the summer.  Which effect is greater is beyond my analysis.
Title: Re: The 2017/2018 freezing season
Post by: romett1 on January 25, 2018, 08:45:29 PM
Temperatures north of 80 degree have gone up and it seems like they are staying at higher levels for the next 5 - 7 days. Image: http://ocean.dmi.dk/arctic/meant80n.uk.php
Title: Re: The 2017/2018 freezing season
Post by: Niall Dollard on January 25, 2018, 09:28:58 PM
Quote
Temperatures north of 80 degree have gone up and it seems like they are staying at higher levels for the next 5 - 7 days.

Looking at latest forecast for the N80 area shows a steady drop in temperatures and by Monday it will be a lot lower than currently (first image) as high pressure takes control

Title: Re: The 2017/2018 freezing season
Post by: jdallen on January 25, 2018, 09:46:13 PM
Temperatures north of 80 degree have gone up and it seems like they are staying at higher levels for the next 5 - 7 days. Image: http://ocean.dmi.dk/arctic/meant80n.uk.php
I wonder if this year's temperatures may be the mirror image of 2016/2017's - "coolish" early and warm late rather than warm early and "coolish" late.
Title: Re: The 2017/2018 freezing season
Post by: romett1 on January 26, 2018, 09:13:24 AM

Looking at latest forecast for the N80 area shows a steady drop in temperatures and by Monday it will be a lot lower than currently (first image) as high pressure takes control

Right, 7-day mean forecast lured me into a trap. Real "hotspot" is over ESS.

Title: Re: The 2017/2018 freezing season
Post by: aperson on January 29, 2018, 12:00:00 AM
GFS and ECWMF have been giving a signal for an unprecedentedly strong Arctic extratropical cyclone in the 10 day range. The signal is lost in ensemble blends due to variability, but control runs and a fair bit of ensemble members are showing this behavior.

It seems to be an effect of the extreme anticyclonic wavebreak over the Kamchatka peninsula that is currently developing, which I note is still being strengthened each gfs run and appears to be a case of dprog/dt due to lack of obs in the region.

I'll post more about it once Feb 1 rolls around and I get to validate my guess of NSIDC extent ~ 13.4 on Feb 1st from early in January.
Title: Re: The 2017/2018 freezing season
Post by: Human Habitat Index on January 29, 2018, 01:04:26 AM
aperson, I find your post very interesting, can you flesh it out a bit for a newbie and/or point me in the right direction so I can investigate myself.
Title: Re: The 2017/2018 freezing season
Post by: A-Team on January 29, 2018, 04:09:48 PM
Quote
an unprecedentedly strong Arctic extratropical cyclone in the 10 day range.
That would set things in motion again but how? There's been minimal correlation between depicted near-surface GFS winds and ice feature displacements for the last couple of months. It would be feasible to morph Ascat images ten days out but better guidance is needed. (Actually it would work better to reconstruct the effective force of winds retrospectively: from observed ice movement.)

The movies below, which are too tall to display here synchronized at 676x1128 pixels, show a hiatus of about a week in mid-January but with some resumption of motion in the Beaufort's CAA floe stringer and Kara export tongue. The indexed color table, ICA2, is fairly effective at distinguishing MYI from FYI and so makes feature tracking easier.

The interest in the former is thick multi-year ice moving into a zone where it will melt for certain in early summer and in the latter for Fram export which may be dominated by ice formed in the Kara in late October 2017. (A refinement of FYI is needed ... perhaps age in months.)

As wind-driven ice flows past Ushakov Island (Остров Ушакова), too tall at 294 m for ice to flow over, a gap in the ice is formed on the downwind (lee) side. The ice soon seals up though as pressure eddies from the sides are unopposed.

On ASCAT scatterometer images, this results in a rough surface which images as white streamers. These are recognizable but not as noticeable on much higher resolution Sentinel-1AB imagery (next post).

Vize Island (Остров Визе), 140 km to the south, has the same effect though it is too small to show up as a standalone feature most days and considerably narrower projected across the direction of ice movement. Its highest point is 22 m and lacks an ice cap.

Together, the two streamers conveniently track the flow of the ice until all the Kara ice is exported (or melts out). Both islands had/have substantial research stations and over-wintering staff so possibly some dramatic footage can be located of ice piling up on the upwind (stoss) side.

This effect is not new nor is it restricted to ice flow (see wipneus' earlier Jan Mayen air flow images). It was very likely the basis for the island's prediction in 1924:

Quote
In 1924, oceanographer Vladimir Wiese studied the drift of Georgy Brusilov's ill-fated Russian ship Svyataya Anna when she was trapped on the pack ice of the Kara Sea. Vize detected an odd deviation of the path of the ship's drift caused by certain variations of the patterns of sea and ice currents. He deemed that the deviation was caused by the presence of an undiscovered island whose coordinates he was able to calculate with precision thanks to the availability of the successive positions of the St. Anna during its drift. The data of the drift had been supplied by navigator Valerian Albanov, one of the only two survivors of the St. Anna.

Finally, the island was discovered on 13 August 1930 by a Soviet expedition led by Otto Schmidt aboard the Icebreaker Sedov under Captain Vladimir Voronin. The island was named after Professor Vize of the Soviet Arctic Institute who was at the time aboard the Sedov and who was able to set foot on the island whose existence he had predicted. wiki
Title: Re: The 2017/2018 freezing season
Post by: A-Team on January 29, 2018, 05:54:33 PM
The Sentinel-1AB radar tile from DTU/Saldo below shows the Kara ice intrusion and islands affecting its flow on 28 Jan 2018. (Schmidt Island, a western outlier of Severnaya Zemlya denoted s, has only a small role.) The streamers from Ushakov and Vize are indicated by Su and Sv respectively. Visible imagery won't be available any time soon at this latitude.

The UH SMOS ice thickness Geo2D for 27 Jan 2018 shows the islands clearly and, as expected, thin ice. However it does not pick up the level of streamer detail that we know must be there, probably because the Kara ice, though mostly new, is itself a matrix of different thickness floes with different histories.

The UH AMSR2 sea ice concentration does pick up the ice diversion around Ushakov for a few days around 03 Nov 2017 (slight slowing of animation; only Oct and Nov shown). However even the highest resolution January images do not show the Kara ice intrusion or its streamers (nor should they). Green shows 100% concentration, a class so abundant that it limits feature imaging.

Come summer melt season, it will be important to know the provenance of ice parcels, of which the Kara ice intrusion is but just one. ASCAT is doing the best at this for now but will be very affected by weather systems later. (It's rather worthless all year along the AK coast and Chukchi in from the Bering Sea.) Sentinel-1AB has a favorable orbital swath for this region but otherwise has incomplete and non-daily coverage.
Title: Re: The 2017/2018 freezing season
Post by: A-Team on January 30, 2018, 02:30:08 PM
Quote
The search for intra-terrestrial intelligent life has largely been futile.
In my view, meteorology-driven 'coupled' models are dead wrong about the end stages of Arctic sea ice loss and disastrously optimistic on its timing, as are upper-bound trenders. Discussion of an ice-free Arctic is commonly avoided using undefined terms like 'seasonally' ice-free' or first ice-free 'summer', then qualified by a non-existent 'consensus' for a million sq km of ice still left in September. The kicker is invariably a picture of that last ice hugging the shores of the CAA.

However that isn't a physically stable state, any more than a pencil thrown out the window coming to rest on its point. We can look forward instead to what is called a stochastic excursional ratchet.

The 156 day mp4 below shows how that would work. Note that with the main ice pack gone, what is the physical mechanism confining last ice to the CAA: the ice is not landfast (grounded), it lifts off poleward with a southern breeze, and ratchets out in prodigous volume through the Beaufort, McClure, Martin, Peary, Nares, and Fram. It won't be coming back either because waves across long fetches of open water will irrevocably mix incoming warm portal water.
Title: Re: The 2017/2018 freezing season
Post by: romett1 on January 30, 2018, 03:40:56 PM
Seems like more open water over Bering Sea (Worldview Jan 29 vs Jan 28).
Title: Re: The 2017/2018 freezing season
Post by: gerontocrat on January 30, 2018, 04:56:49 PM
Discussion of an ice-free Arctic is commonly avoided using undefined terms like 'seasonally' ice-free' or first ice-free 'summer', then qualified by a non-existent 'consensus' for a million sq km of ice still left in September. The kicker is invariably a picture of that last ice hugging the shores of the CAA.

The 156 day mp4 below shows how that would work. Note that with the main ice pack gone, what is the physical mechanism confining last ice to the CAA: the ice is not landfast (grounded), it lifts off poleward with a southern breeze, and ratchets out in prodigous volume through the Beaufort, McClure, Martin, Peary, Nares, and Fram. It won't be coming back either because waves across long fetches of open water will irrevocably mix incoming warm portal water.

Super duper A-Team.

The guys doing these models need to see your animations to properly understand that sea-ice is not static, and build the Arctic (and Antarctic ) movement into their models.

I am happy to admit that it is mainly from your postings that I have fully realised that even in the depths of winter the sea-ice is not a solid lump - rather the reverse. (Sea-ice drift in winter in the Antarctic is also often spectacular)
Title: Re: The 2017/2018 freezing season
Post by: dnem on January 30, 2018, 06:08:57 PM
Quote
The search for intra-terrestrial intelligent life has largely been futile.
In my view, meteorology-driven 'coupled' models are dead wrong about the end stages of Arctic sea ice loss and disastrously optimistic on its timing

Would you hazard a guess on the likely timing?
Title: Re: The 2017/2018 freezing season
Post by: meddoc on January 30, 2018, 07:05:03 PM

Would you hazard a guess on the likely timing?

Well, I guess the Nuclear Weapons Modernization Timelines are a pretty good Indicator:
China: 2019- 21
Russia: 2020
India: 2020- 21
Title: Re: The 2017/2018 freezing season
Post by: magnamentis on January 30, 2018, 07:43:15 PM
Seems like more open water over Bering Sea (Worldview Jan 29 vs Jan 28).

while i agree i assume you are aware that the most part is clouds while indeed the shape below is showing less ice. just wanted to make sure that first glance does not mislead anyone (blue against gray is not ice against ice free ) sorry if that was clear but i had to take a close look to be sure what's showing ;)
Title: Re: The 2017/2018 freezing season
Post by: romett1 on January 30, 2018, 08:02:16 PM
Seems like more open water over Bering Sea (Worldview Jan 29 vs Jan 28).

while i agree i assume you are aware that the most part is clouds while indeed the shape below is showing less ice. just wanted to make sure that first glance does not mislead anyone (blue against gray is not ice against ice free ) sorry if that was clear but i had to take a close look to be sure what's showing ;)

On the first image there are clouds, but ice edge has moved some 10 - 20 km. Looking at temperature forecasts over Bering and Chukchi I guess there is no significant freezing there soon.
Title: Re: The 2017/2018 freezing season
Post by: magnamentis on January 30, 2018, 08:11:10 PM
yeah that's about what i was saying, it has moved but having a quick glance one could get the blue to gray impression. all good, thanks.
Title: Re: The 2017/2018 freezing season
Post by: jdallen on January 30, 2018, 11:02:50 PM
Seems like more open water over Bering Sea (Worldview Jan 29 vs Jan 28).
Most of that Bering extent looks like slash, and probably barely able to keep up with the bottom melt from water that's 2-3C, combined with steadily increasing heat uptake from insolation.  It won't have a chance to thicken, and will vanish quickly once the net heat exchange becomes positive rather than negative.
Title: Re: The 2017/2018 freezing season
Post by: Tigertown on January 30, 2018, 11:44:11 PM
A bad winter as far as thickening of the Arctic sea ice, according to data from the Sentinel satellites.
Click Image to compare January 30th, 2015 through 2018
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2F&hash=35d7d5d7526c9897dfb55501e320295a)
Title: Re: The 2017/2018 freezing season
Post by: Michael Hauber on January 31, 2018, 03:57:19 AM

However that isn't a physically stable state, any more than a pencil thrown out the window coming to rest on its point. We can look forward instead to what is called a stochastic excursional ratchet.


The ice there does not need to be stable.  It just needs to take longer for it to flow or melt away than the summer melt season lasts.

Title: Re: The 2017/2018 freezing season
Post by: Michael Hauber on January 31, 2018, 04:01:58 AM

The guys doing these models need to see your animations to properly understand that sea-ice is not static, and build the Arctic (and Antarctic ) movement into their models.


The sea ice models already have ice movement built into their models. 

Good rule of science - if an amateur, even a gifted one, discovers something, there is a high chance it has already been discovered by the experts, and careful checking should be done before claiming that the experts are not already aware.
Title: Re: The 2017/2018 freezing season
Post by: Shared Humanity on January 31, 2018, 04:45:14 AM
The Garlic Press is operating in the dead of winter!!!
Title: Re: The 2017/2018 freezing season
Post by: Lord M Vader on January 31, 2018, 08:51:32 AM
Should mean a huge compacting and a big widening of the Atlantic sector. The latter one should refreeze and regain all eventually losses. Had this been in March, April, May or June however it should have been devastating for the ice.
Title: Re: The 2017/2018 freezing season
Post by: Neven on January 31, 2018, 09:57:40 AM
The sea ice models already have ice movement built into their models. 

But perhaps not the acceleration (http://onlinelibrary.wiley.com/doi/10.1029/2011JC007110/full) of said movement.  ;)
Title: Re: The 2017/2018 freezing season
Post by: gerontocrat on January 31, 2018, 11:11:29 AM

The guys doing these models need to see your animations to properly understand that sea-ice is not static, and build the Arctic (and Antarctic ) movement into their models.


The sea ice models already have ice movement built into their models. 

Good rule of science - if an amateur, even a gifted one, discovers something, there is a high chance it has already been discovered by the experts, and careful checking should be done before claiming that the experts are not already aware.
If so, then are you also saying that A-Team was wrong in saying that the ice north of Greenland and the CA will not persist in the way the NASA model predicts ? (A-Team says, I think, that NASA does not take (sufficient) account of that that ice is not land fast and if bounded by open ocean to the north would be sent north by southerly winds, then be destroyed by wave action / ocean melt / ocean currents, and would not reform)
Title: Re: The 2017/2018 freezing season
Post by: Gray-Wolf on January 31, 2018, 01:28:22 PM

The guys doing these models need to see your animations to properly understand that sea-ice is not static, and build the Arctic (and Antarctic ) movement into their models.


The sea ice models already have ice movement built into their models. 

Good rule of science - if an amateur, even a gifted one, discovers something, there is a high chance it has already been discovered by the experts, and careful checking should be done before claiming that the experts are not already aware.
If so, then are you also saying that A-Team was wrong in saying that the ice north of Greenland and the CA will not persist in the way the NASA model predicts ? (A-Team says, I think, that NASA does not take (sufficient) account of that that ice is not land fast and if bounded by open ocean to the north would be sent north by southerly winds, then be destroyed by wave action / ocean melt / ocean currents, and would not reform)
Did we not see a great thickness of ice melt out ,in situ, to the north of Greenland in August 2012?
I feel combinations of hostile conditions surrounding this rump ice , coupled with drift/wind forcing will see this ice lost without any changes needed once we turn blue Ocean over late summer in the basin?
Title: Re: The 2017/2018 freezing season
Post by: gerontocrat on January 31, 2018, 03:10:39 PM
Image from Weather-forecast.com below. If it happens (Sunday to Tuesday) there will be some mobility in the ice?
Title: Re: The 2017/2018 freezing season
Post by: A-Team on January 31, 2018, 03:18:02 PM
The mp4 below shows 138 days of Arctic Ocean ice movement from the fall minimum to mid-winter for the last six years (15 Sept to 30 Jan for 2012-13 through 2017-18). Keeping years synchronized allows the same date to be displayed for all six years simultaneously. (Using sequential display, it would be very difficult to compare say Dec 1st for the six years as the frames would be widely separated.)

The year 2014-15 (lower left corner) displays an uncanny resemblance to the current year, at least so far. Both the Kara intrusion and the Beaufort stringer are rather good matches in timing. Presumably synoptic weather patterns and winds were similar. The Beaufort-Chukchi circulation of CAA floes is also seen in 2015-16 (right panel, middle).

TransPolar drift ... what the heck was that, an ice circulation notion from the 80's? Long gone, but still shown in 2018 journals.

Two earlier winters are available as well. I have all eight years butted up going at 1.5 full size (which for Ascat is 1.5*348 x 340 pixels) but there is really no way of posting that on the forum (or viewing on a phone). Again, ImageJ freeware is the best way to go because of how mouse-over is treated on animations.
Title: Re: The 2017/2018 freezing season
Post by: numerobis on January 31, 2018, 03:31:26 PM
GFS and ECWMF have been giving a signal for an unprecedentedly strong Arctic extratropical cyclone in the 10 day range. The signal is lost in ensemble blends due to variability, but control runs and a fair bit of ensemble members are showing this behavior.

In today's ECMWF I'm seeing a low pressure system building over Greenland about now (rather than the high that usually figures there), then heading to the pole on Sunday around 960 hPa and on to the Beaufort by Wednesday next week.

Is 960 hPa unprecedented? In Iqaluit we've had a few storms blow by at 970 hPa, about one a month this fall/winter.
Title: Re: The 2017/2018 freezing season
Post by: RoxTheGeologist on January 31, 2018, 04:46:43 PM
The sea ice models already have ice movement built into their models. 

But perhaps not the acceleration (http://onlinelibrary.wiley.com/doi/10.1029/2011JC007110/full) of said movement.  ;)

How did you derive that answer, Neven?
Title: Re: The 2017/2018 freezing season
Post by: bhenson on January 31, 2018, 04:59:14 PM
GFS and ECWMF have been giving a signal for an unprecedentedly strong Arctic extratropical cyclone in the 10 day range. The signal is lost in ensemble blends due to variability, but control runs and a fair bit of ensemble members are showing this behavior.

In today's ECMWF I'm seeing a low pressure system building over Greenland about now (rather than the high that usually figures there), then heading to the pole on Sunday around 960 hPa and on to the Beaufort by Wednesday next wee

Is 960 hPa unprecedented? In Iqaluit we've had a few storms blow by at 970 hPa, about one a month this fall/winter.

The 0Z and 06Z Wed GFS runs are stronger than the ECMWF, producing a low in the 949-953mb range north of Greenland on Feb. 5-6. Note the slug of mild air (above 0°C) being drawn toward the North Pole.
Title: Re: The 2017/2018 freezing season
Post by: numerobis on January 31, 2018, 07:19:24 PM
Indeed, ECMWF shows it getting above-freezing north of Svalbard.
Title: Re: The 2017/2018 freezing season
Post by: gerontocrat on January 31, 2018, 07:26:55 PM
The sea ice models already have ice movement built into their models. 

But perhaps not the acceleration (http://onlinelibrary.wiley.com/doi/10.1029/2011JC007110/full) of said movement.  ;)

How did you derive that answer, Neven?

Perhaps as ice gets thinner (which it is) and prone to breaks and cracks etc (which it is) then it becomes more responsive to wind, waves and ocean currents? (But I am sure all the models take that into account(?))
Title: Re: The 2017/2018 freezing season
Post by: josh-j on January 31, 2018, 07:47:53 PM
The sea ice models already have ice movement built into their models. 

But perhaps not the acceleration (http://onlinelibrary.wiley.com/doi/10.1029/2011JC007110/full) of said movement.  ;)

How did you derive that answer, Neven?

I would humbly suggest that Neven's answer is derived from the paper he linked to. :)
Title: Re: The 2017/2018 freezing season
Post by: gerontocrat on January 31, 2018, 07:51:32 PM
AbruptSLR posted this link to mashable.com on weird weather

https://mashable.com/2018/01/30/wild-arctic-weather-siberia-temperatures-warm-100-degrees[/#otlLGP0kZgqR

I have put it here because of this quote

Quote
Meanwhile, the unusually high temperatures over Siberia will slide northeastward, toward Alaska and the Pacific side of the Arctic. Once there, it may impede the buildup of winter ice cover, which has been hovering at or near all-time lows for this time of year.

Some computer model simulations sweep an unusually warm air masses across a broad swath of the Arctic Ocean during the next 2 weeks, from the Atlantic and Pacific sides of the Far North. These warm pulses could ensure that Arctic sea ice sets another record low winter maximum.
Title: Re: The 2017/2018 freezing season
Post by: Michael Hauber on February 01, 2018, 01:27:07 AM
The sea ice models already have ice movement built into their models. 

But perhaps not the acceleration (http://onlinelibrary.wiley.com/doi/10.1029/2011JC007110/full) of said movement.  ;)

A 2011 paper, based on AR4 models.  The AR5 models have a faster ice loss, so the issue pointed to in the paper may (or may not) already be fixed.
Title: Re: The 2017/2018 freezing season
Post by: epiphyte on February 01, 2018, 05:37:13 AM
We can look forward instead to what is called a stochastic excursional ratchet.

@A-Team... Just to clarify for those of us running along next to the train, here. You're implying that it's irreversible?

Title: Re: The 2017/2018 freezing season
Post by: jdallen on February 01, 2018, 07:42:15 AM
We can look forward instead to what is called a stochastic excursional ratchet.

@A-Team... Just to clarify for those of us running along next to the train, here. You're implying that it's irreversible?
It is irreversible, short of finding a way to reduce total system enthalpy.

Total heat in the system increases each year.  That sets a floor below which the system can't fall.  That floor means that the 20-22,000KM2 MAX SIE we saw 40-50 years ago is impossible, even with the coldest possible refreeze.  Heck, I doubt we could get past 16,000KM2...
Title: Re: The 2017/2018 freezing season
Post by: echoughton on February 01, 2018, 12:30:12 PM
I just went to weatherbell.com and checked the current radar. Mild in the Chukchi but still vast areas of minus 20-50 over what has been a very cold winter in most of Siberia. Canada to the pole is at or below normal and DMI daily spike has come down to almost normal. That reanylyzer above is smokin some shit.
Title: Re: The 2017/2018 freezing season
Post by: A-Team on February 01, 2018, 12:53:32 PM
Here are 138 days of all eight years simultaneously, all that is available at the ASCAT archive. Earlier years are shown in smaller sizes; 2017-18 is repeated in the lower right corner. A few features are marked up in the initial gif. The mp4 runs from the fall minimum of Sept 15th to 30 Jan.

https://cloudconvert.com/avi-to-mp4 free online with video editing options

Technical note: Surprisingly easy to make, considering it reduces 1104 separate days of images of size 1170 x 1170 (or 1,511,265,600 pixels) to something quite manageable.

In the larger scientific perspective, data is not the same as information. Given massive modern collection schemes, distilling data to information becomes imperative.

It takes quite a bit of experimentation with codecs vs forum software to get the movie playing properly as they are both somewhat black boxes. (As a gif, it would take 65 MB, far too big.) The 696 pixel width displays at greater than 700 pxl forum width, apparently because video resolutions of 420, 720, 1080 are the default options. Try 'reloading' a couple of times if your browser is only displaying an empty controller initially. Or download the file and view on your local movie player.
Title: Re: The 2017/2018 freezing season
Post by: FishOutofWater on February 01, 2018, 07:53:02 PM
No, it hasn't been a very cold winter in *most* of Siberia. In one part of eastern Siberia it has been very cold. We have also been cold in part of eastern North America. However, the western sides of the continents have been very warm as has been the sector of Alaska and Siberia near the dateline.

Dateline blocking has been very strong this winter and it has penetrated into the Arctic.

Title: Re: The 2017/2018 freezing season
Post by: uniquorn on February 01, 2018, 08:18:15 PM
Lincoln Sea Nares. More fast ice letting go?
Title: Re: The 2017/2018 freezing season
Post by: Shared Humanity on February 02, 2018, 03:44:15 AM
Lincoln Sea Nares. More fast ice letting go?

And it is February and Nares has not stopped flowing. Maybe open through the entire winter?
Title: Re: The 2017/2018 freezing season
Post by: jdallen on February 02, 2018, 04:38:27 AM
Lincoln Sea Nares. More fast ice letting go?

And it is February and Nares has not stopped flowing. Maybe open through the entire winter?
That in itself is not unusual.  The Nares has been open all winter several times over the last couple of decades, if I recall correctly.

It is more critical now because of how much less MYI we have left, which is preferentially what is being sucked through the strait.
Title: Re: The 2017/2018 freezing season
Post by: bairgon on February 02, 2018, 12:16:24 PM
Lincoln Sea Nares. More fast ice letting go?

Actually, as can be seen in the gif in the message below, all the ice there was fairly mobile recently. Appears to have stopped on 30th Jan, and started forming an outer "bridge" between Ellesmere and Greenland. However, as you point out this is decaying rapidly.

Lincoln Sea Nares Export from 2017-12-24 to 2018-1-24. One tracked section of ice traveled approximately 115 miles (185km) in 31 days.  Furthest travel in one day was approximately 12 miles (19.3km).
Title: Re: The 2017/2018 freezing season
Post by: meddoc on February 02, 2018, 02:00:25 PM
Just to make Things worse, there is a Polar Vortex Collapse forecasted in 3 days.

Seems like the Cold has had enough over Siberia & now ducking into Greenland' Cover.

Title: Re: The 2017/2018 freezing season
Post by: A-Team on February 02, 2018, 04:58:01 PM
The question is, how will Monday's storm system affect the ice pack? We've been looking at that over at the Nares Strait forum, cross-posted images below, expecting extensive radial shearing as well as translation and compression towards the NH side.

Mobility along the CAA over the last eight years is also shown there; while we expect it to be greater today (for a given wind forcing) with weaker thinner ice, that is not so easy to show. Daily ice motion vectors are compiled at several places (or we could do it ourselves with SIFT etc) but how wind reanalyses translate to actual momentum transfer depend on many other factors such as ridges and keels, leads and concentration, current position of the ice pack relative to boundary conditions (eg islands) and so forth that don't match up for year-on-year same-date comparisons.

(https://forum.arctic-sea-ice.net/index.php?action=dlattach;topic=176.0;attach=96447;image)

(https://forum.arctic-sea-ice.net/index.php?action=dlattach;topic=176.0;attach=96448;image)

(https://forum.arctic-sea-ice.net/index.php?action=dlattach;topic=176.0;attach=96446;image)
Title: Re: The 2017/2018 freezing season
Post by: Niall Dollard on February 02, 2018, 08:35:44 PM
The models this evening are indicating that the main storm centre will track up the Fram Strait late Sunday/Monday and then grind to a halt somewhere between the Pole and Severnaya Zemlya on Tuesday and slowly fill.

The models also show a significant storm surge on its eastern flank. A sig wave height of 10m in the open water just north of Svalbard will create some battering to the ice.

Going on this track, it looks like the worst of the damage will be between Svalbard, Franz Josef and on to Severnaya Zemlya. (but the north coast of Greenland will receive strong westerlies also).
Title: Re: The 2017/2018 freezing season
Post by: Thomas Barlow on February 02, 2018, 09:58:07 PM
Another data-set to add to the mix:
http://people.com/pets/groundhog-day-2018-did-phil-see-his-shadow/
Title: Re: The 2017/2018 freezing season
Post by: subgeometer on February 03, 2018, 01:33:27 AM
Wow, computer breaks for a week and when it comes back up - that's some storm forecast

The ECMWF forecast currently has tit bottoming out at 947mb
Title: Re: The 2017/2018 freezing season
Post by: romett1 on February 03, 2018, 11:38:08 AM
The models this evening are indicating that the main storm centre will track up the Fram Strait late Sunday/Monday and then grind to a halt somewhere between the Pole and Severnaya Zemlya on Tuesday and slowly fill.
After this storm new one is already coming sometime between Thursday and Saturday. Of course it's bit too far, but worth to keep an eye on.
Title: Re: The 2017/2018 freezing season
Post by: A-Team on February 03, 2018, 03:43:16 PM
Some things to watch here are total precipitable water (advection of warm moisture, snow blanket), effect of waves incident to the Barents ice edge (monitorable by UH SMOS thinness and Sentinel-1AB), and induced translation, rotation, divergence, compression and export of the overall icepack (monitorable by Ascat).

This storm could leave an imprint on the upcoming melt season, notably by upending Atlantic Waters along the Barents Edge.

Mercator Ocean has a nine-day forecast of this region at four relevant depths out to 10 Feb 18, the ever-changing color scale masking any drama and precluding pre- and post-storm differencing. They have fixed some earlier programming blunders but still have not corrected overly dynamic palette squashing nor do they release netCDF files so someone else could. 

People frequently post outdated journal factoids to the effect AW is at 300 m depth and so doesn't come in contact with surface ice; actually incoming warmth has long been evident at intermediate depths of 100 m and 30 m as well as the surface. There is abundant buoy and CTD cast data for this region in addition to MercOcean depictions.

http://bulletin.mercator-ocean.fr/en/PSY4#4/47.22/-62.71

GFS is showing 948 hPa attained on Monday with a peak wind of 104 km/hr. For a reality check, there are actual weather stations at Alert CA, Kap Morris Jesup and Nord in northern Greenland, Ny Alesund in Svalbard and FJL, Ostrov Ushakov and SZ in Russia.

https://www.timeanddate.com/weather/canada/alert Alert
https://www.timeanddate.com/weather/@3421844 KMJ
https://www.timeanddate.com/weather/greenland/station-nord/ext Nord
https://www.timeanddate.com/weather/norway/ny-alesund SV
https://www.timeanddate.com/weather/@562426 FJL
https://www.timeanddate.com/weather/@1488349 OU
https://www.timeanddate.com/weather/@1492613 SZ

Technical note: the TPW graphic is not ideal for our purposes, being on a mercator projection sliced meridionally out of Arctic geo-registration, showing only two days out and using a very poor contrast color palette at high latitudes. The version here butts up two copies, crops to emphasize the Bering Strait and Barents regions, inverts the color scheme, tweaks the murky red/magentas to show fainter moisture levels better, and deletes its 14 duplicated pause-frames. This is an extensible product over the full extent of the storm.

For time series overlays of Ascat with any netCDF Geo2D product, note it uses 1154 pixels for a 45º horizon centered on the north pole in Greenland down (-45º) stereographic projection. A similarly oriented Panoply map of size 190 with horizon 25º has diameter 684 pixels. These thus use 25.64 and 15.24 pxl/deg respectively, allowing precision rescaling and auto-registration to the pole. Blueing open water and deleting thicker ice and land mask to transparency creates the overlay onto the Ascat (which has technical problems on marginal ice and open water).

To co-register Nullschool with other map products, adjust the url to orient and size the display. Duplicate a whole-window screen capture, excise the numeric display and time, shrink, and overlay on the main weather display. Setting the size at '2000' allows consistent resizing to fit over standard Ascat or netCDF Panoply maps. Toggling 'overlay' to 'none' gives a wind grayscale for simplified overlays.
Title: Re: The 2017/2018 freezing season
Post by: FishOutofWater on February 03, 2018, 06:54:21 PM
The stratospheric polar vortex has been displaced towards Greenland. That is enhancing the 500mb vortex around Greenland which is going to bring a series of intense storms in the Labrador, Irminger and Greenland seas and into the central Arctic ocean.

The intense storms are blowing very cold Arctic air over the Labrador and Irminger seas at very high speeds. Note that 100 knots, not 100 km/h is the minimum speed of a category 3 hurricane. The repeated blasts of cold air will trigger deep water formation near the shelf slope and a major overturning event in the subpolar seas of the north Atlantic. This will lead to an enormous amount of heat released to the atmosphere and the rapid warming of the Arctic air blown over the subpolar seas.

So much heat will be released that the wave energy will propagate into the upper stratosphere, splitting the stratospheric polar vortex. This splitting will lead to subsidence and high pressure over northern Siberia and easterly flow into Europe from Siberia. Expect western Europe and northern Siberia to be colder than normal for the next  four to six weeks. Expect the Arctic ocean area to have much above normal temperatures for the next 4 to 6 weeks.

Sea ice on the Atlantic side will take a beating from warmth, waves and high dewpoint air. These winds will also import warm water at depth into the Atlantic side of the Arctic ocean while cold Arctic water is exported from the Arctic through the Labrador sea and down to the bottom of the north Atlantic.

This is a major planetary event that will couple the processes from the bottom of the North Atlantic to the top of the stratosphere. Watch it carefully as it evolves. I expect it will be the topic of a number of scientific papers in the years to come. Note that both the ECMWF and GFS models predict this vortex splitting event and have been predicting it for days.
Title: Re: The 2017/2018 freezing season
Post by: Jim Hunt on February 03, 2018, 08:31:41 PM
The state of play in the Arctic as the latest Fram Strait cyclone is brewing:

http://GreatWhiteCon.info/2018/02/facts-about-the-arctic-in-february-2018/

Including an animation revealing the effects of the previous set:

http://youtu.be/oV3Px946Kwk

It has been noted that the latest PIOMAS thickness map from Wipneus shows sea ice where the satellites reckon there is none.
Title: Re: The 2017/2018 freezing season
Post by: A-Team on February 03, 2018, 08:55:03 PM
Great to see people coming out of hibernation for this event!

Here are the 'before' Sentinel radar image of the ice for 02 Feb 18 (needs click for full scale) and the side-by-side water temperatures by depth for the same date.

Sea water at these depths and salinities freezes at about -1.81ºC. Surface temperatures are not remotely close now; mixing open water to intermediate depth would make things worse along a 1000 km corridor. Winds don't mix water under ice but year-round currents would move mixed Atlantic Waters east along the Barents Edge continental shelf bathymetry, propagating open water (or early melt).

Finally, just a variation on what JimH already did above. The 'large' version of UH AMSR2 sea ice concentration does quite a bit better around all these little islands. Given the winds more or less orthogonal to the ice edge, it's also worth tracking the less-than-100% ice because it is a prime candidate for consolidation, with low freeboard floes swamped with sea water and fractured by swells possibly a couple hundred km (!) into the ice pack.

The last frame averages out AMSR2 weather flashes over the 33 days and differentiates less solid areas from those consistently all ice. It's repeated as a standalone prediction of the post-storm compaction zone. There'll also be ice piling up on the southern shores of FJL and extended ice eddies on the lee side of Ostrov Ushakov.

Technical note: the UH ftp site is fast, soit takes but a minute to round up the files, change names, drag'n'drop into ImageJ, rotate 90º, crop to the Barents Edge, montage in date text, change colors in gimp off the palette with the color picker, pause on 02 Feb 18 and less-than-solid average, save out as small gif, upload, and get back to gardening before it gets any hotter.
Title: Re: The 2017/2018 freezing season
Post by: Thomas Barlow on February 04, 2018, 03:40:36 AM
2018 Arctic extent still lowest on record for most of January.
Looks like it 'might' claw its way back into the crowd if it keeps trying:

http://nsidc.org/arcticseaicenews/charctic-interactive-sea-ice-graph/
Title: Re: The 2017/2018 freezing season
Post by: nicibiene on February 04, 2018, 09:29:21 AM
Great to see people coming out of hibernation for this event!

No hibernation here.  ;D Highly apprechiate to read the discussion and your amazing graphics here A-Team. I'm following the weather models, trying to learn and to think about (guess) what will happen next. Helpful to read all your information and opinions here. Thanx guys!  :-*

It could be a nice entertaining thriller, if it wouldn't be so scary realistic.... :'(
Title: Re: The 2017/2018 freezing season
Post by: Paddy on February 04, 2018, 09:36:35 AM
The one consolation in all this is that at least albedo still doesn't matter that much until after the equinox. However, thete's really not much time left for a refreeze if this drives unseasonsl melt.
Title: Re: The 2017/2018 freezing season
Post by: meddoc on February 04, 2018, 10:49:30 AM
I've never seen such a Storm that close to the Pole in Winter, since nullschool.net is available for public Use.

Probably no Coincidence, that the Land of the Free just declared in their renewed Nuclear Doctrine, that basically they can attack Anyone, Anywhere without any Reason whatsoever, if necessary.

These are the Times, we' re livin in.
Title: Re: The 2017/2018 freezing season
Post by: Jim Hunt on February 04, 2018, 11:14:43 AM
The latest Fram Strait swell forecast for tomorrow afternoon:

http://GreatWhiteCon.info/2018/02/the-february-2018-fram-strait-cyclones/

Note that this is just the underlying long distance swell. There are giant wind waves superimposed on top of that. See the last image. Note also that "significant height (https://en.wikipedia.org/wiki/Significant_wave_height)" does not refer to the biggest waves:

"Statistically, it is possible to encounter a wave that is much higher than the significant wave.

Given that Hs is 10 metres (33 feet), statistically:

1 in 10 will be larger than 10.7 metres (35 ft)
1 in 100 will be larger than 15.1 metres (50 ft)
1 in 1000 will be larger than 18.6 metres (61 ft)"
Title: Re: The 2017/2018 freezing season
Post by: A-Team on February 04, 2018, 03:17:24 PM
The first image below shows ice along the North Atlantic front on 03 Feb 2018 prior to the storm. A major retreat of ice position can be expected over the next few days.

The mp4 provides some context: 142 days since the 15 Sep 2017 minimum ending on the Feb 3rd. Ascat is fairly noisy when the scene has weather over a mix of open water and ice but the back and forths of the front can still be followed. Ice in the upper Fram will be churned, melted into open water. Scribbler has a good discussion of the extreme advected warmth:

https://robertscribbler.com/category/climate-change-2/

The mp4 for the overall Arctic Ocean shows Fram export really kicking in about day 300. This represents 39% of a full year (minimum to minimum rather than calendar); ice features in the peri-polar region have been stable with no decisive trend in direction (ie the 'TransPolar Drift' is a non-starter).

The transit of the cyclone has slowed since yesterday (per GFS nullschool) and extremes of low pressure and wind have slightly abated. However the winds have been strong and consistent in direction. The central ice pack will be pushed down onto the immovable CAA deforming features and forcing more to the sides, and so accelerating both Beaufort and Fram export of older thicker ice (along with Kara/Laptev intrusion ice).
Title: Re: The 2017/2018 freezing season
Post by: charles_oil on February 04, 2018, 06:01:46 PM

Climate re-analyser looks like impressive temperature anomaly too !


http://cci-reanalyzer.org/wx/fcst/#gfs.arc-lea.t2anom
Title: Re: The 2017/2018 freezing season
Post by: A-Team on February 04, 2018, 08:14:12 PM
Quote
Climate re-analyser: impressive temperature anomaly
Whoa, that is an anomalous anomaly. (I had trouble reading the scale so color-picked the extremes, pooled, and re-colored them as yellow.) The Ny-Ålesund weather station is a little off to the south but it has excellent records (and a daily sonde).

If persistent enough to warm the ice, we may see a tussle between fracturing and flow. Brittle to ductile transitions in ice are discussed in this 1999 classic:

http://www.tms.org/pubs/journals/JOM/9902/Schulson-9902.html
Title: Re: The 2017/2018 freezing season
Post by: dnem on February 04, 2018, 08:32:30 PM
Quote
Climate re-analyser: impressive temperature anomaly
Whoa, that is an anomalous anomaly.

That station is around -1 right now or an anomaly of around +13C.  That would make it more or less in accord with the re-anayzer (in the brown colors on the anomaly scale), and both cooler than, and south of, your yellow color-replaced region.  If I'm looking at it right.
Title: Re: The 2017/2018 freezing season
Post by: Neven on February 04, 2018, 11:38:39 PM
Thanks for all the info, everyone. I'm also watching somewhat more intently than I usually do around this time of year. I'll try and incorporate some of the stuff in the next PIOMAS update, or perhaps do a separate blog post (if time and circumstance permit).

Here's my modest contribution, the Climate Reanalyzer precipitation forecast for the coming 10 days:

http://pamola.um.maine.edu/wx_frames/gfs/arc-lea/prcp-mslp-gph500/mp4/gfs_arc-lea_prcp-mslp-gph500_2018-02-04-12z.mp4
Title: Re: The 2017/2018 freezing season
Post by: Pmt111500 on February 05, 2018, 03:08:34 AM
Thanks again A-Team...
Quote
... ; ice features in the peri-polar region have been stable with no decisive trend in direction (ie the 'TransPolar Drift' is a non-starter ...

We clearly need some new thoughts on how the Arctic Sea Ice drifts. I've been assuming Transpolar Drift would be more of a constant feature also when there's no ice essentially forming almost an unidirectional flow through Bering straits bringing warmer Pacific water to Arctic Atlantic. The height of sea level is almost always higher at Bering than Atlantic ice edge so I've thought it could stack on the ESS shallows flowing transpolarly straight to Fram.

This might not be the case in the future.  In any case, we do not (yet) have a fully liquid ocean at a rotational pole of a planet to look at as an exsample, so some theorizing might, could, should be done. Of course we'll see how it settles once it's ice free, but the Greenland messes with the incoming currents for the time being.
Title: Re: The 2017/2018 freezing season
Post by: Ice Shieldz on February 05, 2018, 04:26:51 AM
Forecasts pointing toward several more days with an active north Atlantic cyclone cannon, albeit perhaps not with cyclones as strong and/or invasive as the current one. My understanding is that the onset of this northward heat transfer caused models to forecast our upcoming SSW – which will split the polar vortex and couple tightly with the troposphere. This opens the door for more cyclones and associated WACCy weather. Below is a 65N 10hpa zonal wind forecast and an animated ECMWF 10-day forecast for 10hpa winds.
Title: Re: The 2017/2018 freezing season
Post by: FishOutofWater on February 05, 2018, 05:09:58 AM
There's very strong wave 2 driving causing this polar vortex split. Nice animation of the ECMWF forecast which is is good agreement with the GFS forecast. We are paying attention to the Atlantic side right now but there has been a very strong MJO wave that moved from the Indonesian sector to the west Pacific sector. There has also been persistent ridging in the east Pacific driving storms and atmospheric wave energy towards the Bering strait. This has set up the powerful wave 2 event which is coupling the troposphere with the stratosphere.

The models are not destroying the vortex on the north American side so don't expect a very cold spring and May - June storminess like 2013. This will be a strong splitting event, but I don't think it will cause persistent stratospheric subsidence over the pole like we saw in 2013. The stratospheric subsidence will shorter lived than 2013 it and will be mostly over northern Siberia.

Note that the surface winds and sea surface height gradients will continue to favor more cold fresh water export than normal through the CAA. Water from the Beaufort gyre's fresh water pool has been released to the Labrador sea for the past 15 months or more. I don't think the transpolar drift has been entirely disrupted but fresh water and sea ice have been substantially diverted towards the Labrador sea.

The figure shows extremely high heat flux for wave 2 on 10February18.
Title: Re: The 2017/2018 freezing season
Post by: Ice Shieldz on February 05, 2018, 06:32:00 AM
Fish - Thanks for that most interesting clarification. Also, fascinating how the tropics affect the Arctic via the MJO. It was 5 days ago where we had the 'highest amplitude MJO event on record (back to 1979) over the West Pacific.'  https://twitter.com/NWSCPC/status/958796146952015872 (https://twitter.com/NWSCPC/status/958796146952015872)
Title: Re: The 2017/2018 freezing season
Post by: Jim Hunt on February 05, 2018, 09:49:40 AM
The current cyclone was down to 952 hPa at midnight according to Environment Canada:

http://GreatWhiteCon.info/2018/02/the-february-2018-fram-strait-cyclones/#Feb-05
Title: Re: The 2017/2018 freezing season
Post by: Alexander555 on February 05, 2018, 12:27:46 PM
I dont know how reliable it is, but the pic for Saturday is 942 hPa. And a few days later the lowest i see is 931 hPa.
Title: Re: The 2017/2018 freezing season
Post by: A-Team on February 05, 2018, 12:34:09 PM
Quote
need some new thoughts on how the Arctic Sea Ice drifts
In part because the Bering Strait still has a high sill of 53m at current sea level, relatively little Pacific water, none deep, enters the Arctic Ocean relative to inflows of Atlantic Waters which contribute ~10x the volume. Since the volume of the AO is not increasing, an equal volume exits after circulating (for years) as bathymetric boundary currents. These are hundreds of meters below the surface and do not transport ice whose motion sums wind-driven and near-surface currents.

Moorings set by A Muenchow have measured the Nares component of AW export (which cannot be confused with PW). Increasing Atlantification far along the Siberian side, again documented with mooring and profiler data, is captured quite well in MercOcean displays even at (storm affected) 30 m depth whereas less influence is seen from the Pacific.

From my perspective, there's no further purpose served in discussing the non-operative Transpolar Drift. The eight consecutive years of ASCAT imagery (up-forum) prove conclusively that the ice does not move in that manner in the seasons covered. This imagery has far too many internal controls to be mis-interpretable.

That is why TPDrifters don't post satellite time series supporting their views -- there aren't any. However journals keep it alive -- entrenched scientific ideas change one funeral at a time.

It's nonetheless interesting to consider how the ice moved in the past, for example during the 100,000 years that the Pacific and Arctic oceans were disconnected by Beringia. Inflows began at 11,000 BP as ice sheets melted but these must have been initially incremental. Meanwhile a km thick central ice pack was leaving scours on the Lomosonov Ridge and a vast ice sheet over the Barents Sea was melting out.

We can't very well discuss future ice motion since the AO will be ice-free but intermediate years with a smaller, thinner and seasonably variable ice pack will be susceptible to unforeseeable weather, winds and long-fetch waves. Oceanic circulation in an ice-free Arctic? Most of the model effort goes into what will happen with the AMOC heat re-distribution.

The inset animation tracks the motion of a curious feature (virtual buoy) from the Sept minimum until early February 2018. The first frames show the unexplained polynya off the Laptev that had many posts this summer flanked by horns of brighter ice, presumably MYI.

Over time, the feature remains quite recognizable despite moving indecisively towards the Fram while experiencing considerable deformation (stretching). However I expect winds associated with this storm to measurably deflect the feature towards the CA/AK.

Technical note: the ASCAT map projection is conformal, conserving angles but not areas; map scale changes with distance from the pole, making quantitative shape change measurements problematic.

Normal buoys are point-like objects, usually very few in number, placed in floes in late spring followed shortly by high attrition. Virtual buoys are free and dense in coverage throughout the year, providing dimensional extent and orientation which allow tracking of position, rotation and deformation for years at a time. If someone looks at the data.

Although we are seeing Arctic DEMs and bathymetry in netCDF format, this has not yet been used to store images probably because png provides extensive lossless compression. However applying ncgen to a 8-bit grayscale value geolocated grid like an ASCAT image would offer some advantages, like instant application of the 100+ map projections of Panoply (some equal area), instant false coloring with the 100+ palettes, and quantitative inter-operability with whatever other Arctic data is in netCDF format.
Title: Re: The 2017/2018 freezing season
Post by: Pmt111500 on February 05, 2018, 01:12:23 PM
Oh, Transpolar Drift has stopped working?!? Front cover story, renew the front page!   ;D 8) :P. Thanks also for the rest of 'current studies on currents'-newsflash. The Atlantification of Arctic Ocean has clearly progressed further in recent years, yes.
Title: Re: The 2017/2018 freezing season
Post by: Jim Hunt on February 05, 2018, 01:23:26 PM
A Sentinel 1B SAR image of the ice edge yesterday:
Title: Re: The 2017/2018 freezing season
Post by: romett1 on February 05, 2018, 02:32:45 PM
Waves currently north of Svalbard according to ECMWF.
Title: Re: The 2017/2018 freezing season
Post by: A-Team on February 05, 2018, 04:44:21 PM
Quote
Oh, Transpolar Drift has stopped working?!? Front cover story!
As mentioned, TPDrifters never post evidence supporting their views, though nothing could be easier. It seems for recent years, there isn't any. They just keep repeating what they were taught long ago in school, even in the face of conflicting current data.

Many floe tracks do exit the Fram, others the Nares, still others via the Barents islands or CAA garlic press (like the single functioning Obuoy), and in recent days, some left to the south out to the Bering Sea (reverse TPD?) per Modis. Many central traces never leave, they simply mill about or stall for as long as they can be followed.

We followed the journey of Big Block over many months up the AK coast before it stalled, broke up and melted out in the warmer Chukchi. Six of the last eight years have shown the same local pattern. The 'goat's head' too was followed for a long time in an earlier winter.

This year, Fram exiting was practically non-existent during the summer and early fall but picked up suddenly around day 298 (Oct 25th). That can be seen on either on Ascat or the Piomas volume export chart that wipneus posted the day before:

(https://forum.arctic-sea-ice.net/index.php?action=dlattach;topic=119.0;attach=96500;image)

Fram export area this fall, winter and spring will be dominated at the 85% level by export of the Kara Sea intrusion, ice that was formed there in late October (TMI or third month ice). Some FYI from the Laptev will also contribute, as it often has in recent years.

Additionally, small but thick areas of Greenland and CAA-flanking ice will exit, along with some deformed central ice. These later losses play a disproportionate role in pinching out trends to zero in multi-year ice age class proportions.

Not a single floe from the Beaufort-Chukchi-ESAS western sector is at risk of TPD transport out the Fram/Barents/Nares over the July 2017 to May 2018 time frame. Disagree? Show me the floe.

It would be great to have nullschool-like sprites tracking ice movement. These feature sprites would initiate, flow along their variable length path for variable lengths of time, terminate upon breakup, melt or exit.

Buoys can contribute multi-year drift tracks but there aren't nearly enough of them. Worse, there are very significant biases in shipboard release position, season of installation and cessation of function.

It is easy to automatically characterize day-on-day ice movements but much harder to do path integrals of the resulting velocity vector field. That's because there's not necessarily ROI handoffs one day to the next.

However fancier (but still sub-optimal) contrast post-processing (up-forum mp4) reveals a near-saturation density of potential sprites lurking in ordinary Ascats. It doesn't seem very dignified to track these manually but in fact it can be done very rapidly in ImageJ. That's because it's primarily cell biology software and those scientists have forever been wanting to track movement of cells and interior stained features, so it's been developed to the nth degree of convenience (in 5D no less).

TPD is ill-posed, boring. It is the sprites product that is needed. From that trajectory database, the rest follow: convergence, divergence, deformation, volume loss by thickness class, etc. From there, comparative mobility measures.

Below, the image flicker from the two past days (before full storm onset) show significant one-day movement of the pack in the direction expected from strong persistent winds, 'ENE' to 'SSW' as the map is laid out. Indeed there seems to be a central swath of deformation, not just bulk translation, between essentially stationary ice. Sentinel-1AB can differentiate between shear and plastic deformation along the interfaces.

Technical note: 16-bit 3-channel Sentinel-2AB revolutionized cryosphere imagery processing (unlike land scenes, ice is basically white on white). Ascat is offered as 24-bit color png but the three channels are identical, thus it is really 8-bit grayscale. The question is, does changing to 16-bit gray in ImageJ options prior to global and locally aware contrast stretching bring any benefit? That could nuance two intermediate round-off steps but ultimately the monitor will be displaying an 8-bit gif. So the gains may be modest except when zeroing on in special small regions where every bit helps.
Title: Re: The 2017/2018 freezing season
Post by: Niall Dollard on February 05, 2018, 04:53:17 PM
As the big storm moved up through the Fram, west winds have pulled the ice away from the east coast of Greenland at Joekelbugt.

Title: Re: The 2017/2018 freezing season
Post by: Michael Hauber on February 06, 2018, 02:26:24 AM


Fram export area this fall, winter and spring will be dominated at the 85% level by export of the Kara Sea intrusion, ice that was formed there in late October (TMI or third month ice). Some FYI from the Laptev will also contribute, as it often has in recent years.

Not a single floe from the Beaufort-Chukchi-ESAS western sector is at risk of TPD transport out the Fram/Barents/Nares over the July 2017 to May 2018 time frame. Disagree? Show me the floe.


I thought transpolar drift was primarily drift of ice from Laptev towards Fram Strait, which you seem to acknowledge occurs.    And not ice from Beaufort or Chukchi,  Maybe ESS.  Wikipedia (https://en.wikipedia.org/wiki/Transpolar_Drift_Stream) defn

Edit:  Polar bouy (http://psc.apl.washington.edu/northpole/Buoys.html) tracks seem to provide significant support.
Title: Re: The 2017/2018 freezing season
Post by: FishOutofWater on February 06, 2018, 02:37:17 AM
A-Team, for your amusement I have a reference from your favorite science source, the Daily Mail.
http://www.dailymail.co.uk/news/article-464768/Thousands-rubber-ducks-land-British-shores-15-year-journey.html


Thousands of rubber ducks to land on British shores after 15 year journey

By BEN CLERKIN

Last updated at 22:00 27 June 2007

They were toys destined only to bob up and down in nothing bigger than a child's bath - but so far they have floated halfway around the world.

The armada of 29,000 plastic yellow ducks, blue turtles and green frogs broke free from a cargo ship 15 years ago.

Since then they have travelled 17,000 miles, floating over the site where the Titanic sank, landing in Hawaii and even spending years frozen in an Arctic ice pack.

And now they are heading straight for Britain. At some point this summer they are expected to be spotted on beaches in South-West England.

While the ducks are undoubtedly a loss to the bath-time fun of thousands of children, their adventures at sea have proved an invaluable aid to science.


I'm not going to argue for or against the transpolar drift because these days an individual ice floe would melt before it crossed the Arctic, but how about these rubber duckies that made it from the Pacific to the Atlantic through the Arctic ocean? I'm not sure what we call it but there is some through flow from the Pacific to the Atlantic.
Title: Re: The 2017/2018 freezing season
Post by: Niall Dollard on February 06, 2018, 09:14:47 AM
That's very good, Fish.

It's a nice graphic but likely incorrect in showing the ducks taking a track to the east of Iceland, when it would be far more likely to bob along with the East Greenland Current to the west of Iceland.

but how about these rubber duckies that made it from the Pacific to the Atlantic through the Arctic ocean? I'm not sure what we call it but there is some through flow from the Pacific to the Atlantic.

How did they do it ? They made their way through the large quacks in the Duckchi Sea, of course.

I'll get my coat...... :D

Title: Re: The 2017/2018 freezing season
Post by: Phil. on February 06, 2018, 11:54:19 AM
This is the original map.

https://en.wikipedia.org/wiki/Friendly_Floatees#/media/File:Friendly_Floatees.png
Title: Re: The 2017/2018 freezing season
Post by: gerontocrat on February 06, 2018, 03:17:14 PM
With all eyes on Rubber Quacks, (it took 8 years to cross from the Bering Strait to the Fram - not much of a transpolar drift), I had a look at the Pacific end. It seems above freezing in the Bering Sea and right up into the strait - warmish winds from the south. Not much new ice to form there, if any?
Title: Re: The 2017/2018 freezing season
Post by: A-Team on February 06, 2018, 03:51:17 PM
Here are two variant visualizations of the two-day motion attributable to the storm. These compare the 3rd to the 5th of February. The wind power density on the 4th is also shown at the surface; for reasons explained way up-forum, this may be more appropriate to momentum transfer than wind speed per se.

Along the central swath of WPD, the displacement is ~45 km which is about a km per hour. It would take 62 days at this rate for the white star to reach the MacKenzie Delta. Current conditions will persist for only a few more days however.

Not all the ice is moving in that direction by any means; there are even fixed points. Along the CAA, the movement is eastward. Some of that is attributable to local wind direction but the rest is deformation in response to the central swath. Poleward motion of the Kara tongue then squeezes ice above Morris Jesup out the Fram.

Technical note: The Ascat sea ice product is ironically a byproduct of its primary purpose which is wind speed measurement over the oceans. However nullschool does not use that data directly (or indirectly?) for its wind maps. That's unfortunate for synchronicity: the 4 hour GFS intervals are then not tied to timing of the EUMETSAT MetOp-A orbital swaths that generate the daily Ascat posted at Noaa.

The other issue with this is masking rain and open water on the Arctic Ocean perimeter that make Ascat sequences are quite flashy in the Bering Sea and Chukchi for reasons unrelated to sea ice. This is also a huge problem along the eastern Fram and Barents Edge.

It's possible however to pull out a one-time land mask (which Ascat does not provide) plus daily open water masks from UH AMSR2 3.125 km determinations of sea ice concentration. These are readily applied to Ascat images to cover up everything but the ice (to whatever concentration bound), thus better displaying effects of the storm. Here again the swath timings of these products are difficult to match as only the former is in the A-train satellite constellation.

It is critical here to get the AMSR2 rescaled to match the unstated scale of Ascat because of narrow island passageways and straits. Both use the same projection and orientation and both extend out to the 45th parallel (look for upper Lake Michigan). That means the two diameters can be measured to very low error; the correct downscaling of AMSR2 then follows, as does coincident alignment of north poles (not marked on Ascat).

These operations easily scale to thousands of image pairs, so to the entire joint record. While we could use it during this storm, a more important application may be to the summer melt season when Ascat imagery has so many weather distractions that feature sprites are difficult to maintain.

Since there is effectively no scientific presence on Arctic sea ice for nine months a year, it is important to wring every last bit of information out of what satellite data is available from radar windows.

Here masking out both land and open water artifacts allows gathering of daily contrast statistics that can rationally and reproducibly optimize image enhancement, though the human perceptual component can never be disregarded especially with indexed color palettes. Algorithmic determination of deformation also greatly benefits from prior region-of-interest enhancement.

Once superimposed, the AMSR2 could also be used as a second color channel to Ascat. For that a proper Geo2D netCDF is needed so that concentration could be represented as grayscale. Seasonally, SMOS ice thickness could be used as a third channel. Color would provide vastly improved feature discrimination. Alternatively, Ascat grayness amounts to a DEM upon which AMSR2 or SMOS can be draped as a hillshaded surface.

However at the end of the day, Ascat provides only 86,500 = 294*294 pixels for the Arctic Ocean proper (which is 380x330 as a Greenland-down rectangle). That's an 8.3% payload out of the initial file. It would be great to have twice the resolution or 16-bit sensitivity but those may not arrive before the ice is gone.

http://www.remss.com/missions/ascat/ best source of Ascat technical information
Title: Re: The 2017/2018 freezing season
Post by: jdallen on February 06, 2018, 11:33:19 PM
With all eyes on Rubber Quacks, (it took 8 years to cross from the Bering Strait to the Fram - not much of a transpolar drift), I had a look at the Pacific end. It seems above freezing in the Bering Sea and right up into the strait - warmish winds from the south. Not much new ice to form there, if any?
I think the key right now won't be the effects on extent and area, rather what will happen to both net heat flow out of the water and general ice thickening over the next six weeks.  It seems to me the timing of the vortex split couldn't be worse, as it will encourage the creation of strong spring storms on the Atlantic side that will drag both latent and direct heat into the basin.
Title: Re: The 2017/2018 freezing season
Post by: FishOutofWater on February 07, 2018, 12:49:15 AM
All of Alaska has now seen the first dawn of the new year. NASA Worldview visible images show thin, weak floes moving through the Bering strait into the Arctic ocean over the past few days at the same time southerly winds pounded the Atlantic side of the ice pack.

Arctic oceanography models have have predicted increasing flow through the CAA as the Arctic warms and the ice thins. I have no doubt that we have seen that happen over the past 2 years and that this weather will continue that trend. The buoy in the main channel of the CAA is the closest thing we have today to rubber duckies.

Close examination of the Mercator ocean salinity maps, from 0 to 100 m depth, over the past 2 years has led me to conclude that a large amount of fresh water stored in the Beaufort gyre has been released through the CAA over the past 15 months.

The atmospheric wave 2 pattern in the NH driving the polar vortex splitting event may be amplified by the lack of sea ice to the SW of the Bering strait and the deficiency of sea ice in the Barents sea. I think we are now seeing coupled ocean/atmospheric processes associated with declining Arctic winter sea ice.
Title: Re: The 2017/2018 freezing season
Post by: Ice Shieldz on February 07, 2018, 01:44:10 AM
Zoom in on sea ice movement for 02/04 thru 02/06 at Cape Morris Jesup (northern tip of Greenland). Rough estimate of 46 miles (74km) of travel for one tracked section of ice.
Title: Re: The 2017/2018 freezing season
Post by: Thomas Barlow on February 07, 2018, 06:30:09 AM
Are there going to be ANY functioning webcams in the Arctic Ocean this year?
http://obuoy.datatransport.org/monitor#overview/gpstracks
Title: Re: The 2017/2018 freezing season
Post by: Jim Hunt on February 07, 2018, 10:49:27 AM
Are there going to be ANY functioning webcams in the Arctic Ocean this year?

Maybe?

http://imb-crrel-dartmouth.org/imb.crrel/newdata.htm
Title: Re: The 2017/2018 freezing season
Post by: A-Team on February 07, 2018, 01:05:50 PM
The storm is bringing amazing displacements and deformation of the ice pack. For meridional scale, Ushakov Island is 1021 km from the north pole. (That's the island between SZ and FJL that has been providing the rubble ridges as Kara Sea ice moved past into the Arctic Ocean. Those white streamers have provided directly visible motion trajectory records -- sprites -- for the last four months but now are deforming badly.)

The first derivative of the image sequence shows the central swath displacement from SZ right up over the pole and down towards Amundsen Gulf. The Chukchi and ESAS are not participating to any extent, just milling about. (The proprietors of Ascat have normalized the backscatter of its C-band radar to a bounded geolocated scalar field, the daily grayscale.)

This storm does not seem that remarkable compared to ones last year in terms of TPW advection.

The final animation shows overall motion as viewed from a North Atlantic perspective.

It's also of interest to match up wip's animation of the last 3 months of Piomas thickness with Ascat's perspective on where the thick ice resides and how it has been moving.

Piomas could be used to determine and track the motion of the icepack's center of mass which might be used with the moment arm of wind power density to torque ice pack rotation. However GFS has completely changed its story today, meaning a ice movement forecast based on yesterday's depiction would already be worthless.

The Arctic Ocean is very much constrained by the particulars of its basin so it's worth looking at a change of radial coordinates to PS centered at 85.8N, 176.15E to see if that fits Ascat motion better. The largest block of ice that can rotate freely is 2016 km in diameter touching Ellesmere, Komsomolets and Genriyetta islands. The lat lon grid is easy to draw in Panoply and overlay on Ascat mp4's. https://doi.org/10.1017/S003224741300051X
Title: Re: The 2017/2018 freezing season
Post by: Jim Hunt on February 07, 2018, 02:04:26 PM
It may take a while for me to get the animation working on the forum, but here's AMSR2's overview of the side effects of the recent cyclone:

http://GreatWhiteCon.info/2018/02/the-february-2018-fram-strait-cyclones/#Feb-07

PS. Just clicking the GIF image seems to do the trick.
Title: Re: The 2017/2018 freezing season
Post by: Jim Hunt on February 07, 2018, 02:14:05 PM
The latest Arctic Sea Ice News:

https://nsidc.org/arcticseaicenews/2018/02/sea-ice-tracking-low-in-both-hemispheres/

Quote
January of 2018 began and ended with satellite-era record lows in Arctic sea ice extent, resulting in a new record low for the month. Combined with low ice extent in the Antarctic, global sea ice extent is also at a record low.
Title: Re: The 2017/2018 freezing season
Post by: A-Team on February 07, 2018, 02:24:39 PM
Thx Jim, very helpful.

The leeward polynyas are coming in as expected. The plunge in sea ice concentration poleward ... we'll have to wait and see if those hold up as AMSR2 can display a lot temporary weather artifacts (eg when the center of a cyclone passes over). There's some nice Sentinel-1AB passing by at http://www.seaice.dk/latest/; the one below needs a click to display at the provided resolution.

Title: Re: The 2017/2018 freezing season
Post by: magnamentis on February 07, 2018, 04:34:34 PM
The latest Arctic Sea Ice News:

Quote
January of 2018 began and ended with satellite-era record lows in Arctic sea ice extent, resulting in a new record low for the month. Combined with low ice extent in the Antarctic, global sea ice extent is also at a record low.

this and the lack of extraordinary cold weather above in places where is ice now, more the opposite, it was way warmer than average, i have (like so often before) my serious doubts about sea ice volume numbers. record or close to record lows in area and extent almost permanently and how should the volume be significantly higher than last year? after all the ice which is now in place would have to be much thicker than last year despite the fact that it's permanently as warm or warmer.

i still believe that in the not so far future we shall see massive changes/correction in piomas algorithms, too many times things don't look right or intuitive other than the general trend which is correct but then obvious and undeniable as well.
Title: Re: The 2017/2018 freezing season
Post by: Sleepy on February 07, 2018, 05:46:54 PM
Here goes the PV...
Title: Re: The 2017/2018 freezing season
Post by: Thomas Barlow on February 07, 2018, 10:02:39 PM
Are there going to be ANY functioning webcams in the Arctic Ocean this year?

Maybe?

http://imb-crrel-dartmouth.org/imb.crrel/newdata.htm
Thanks !
Title: Re: The 2017/2018 freezing season
Post by: werther on February 07, 2018, 10:03:56 PM
Small contribution. Good animation by Jim Hunt, showing the impact of that Low.
I don't want to put in as much time as I did some years ago. But still keeping an eye on the main events.
NCEP NCAR comparisons do show this winter's power sliding to levels seen during '15-'16, which is a bad sign. Chukchi region is worse, Atlantic side still a bit better than then.
Rest of feb left to change things for the better...
Title: Re: The 2017/2018 freezing season
Post by: Jim Hunt on February 07, 2018, 11:31:27 PM
Thanks !

It's by no means certain I'm afraid. Most years an IMB buoy with associated webcams gets installed near Barneo in April. Sometimes the other IMB buoys have a webcam pointed at them, but more often they don't.
Title: Re: The 2017/2018 freezing season
Post by: A-Team on February 07, 2018, 11:58:53 PM
Quote
i have serious doubts about sea ice volume. lows in area and extent almost permanently how should the volume be significantly higher it's permanently as warmer. we shall see massive changes/correction in piomas algorithms, too many times things don't look right.
That view may be widely shared in the scientific community. Otherwise, why continue to pursue observational ice thickness, like Cryosat, Topaz, SMOS, and do all the field work? In my view, UH SMOS is the most accurate -- and most disturbing -- of the bunch (in its speciality, the thinner ice). However ice thickness may be heading to a hybrid product that integrates Cryosat, Piomas, and SMOS.

Some cross-posted images from the Piomas forum around #2268:

(https://forum.arctic-sea-ice.net/index.php?action=dlattach;topic=119.0;attach=96668;image)
Title: Re: The 2017/2018 freezing season
Post by: Sleepy on February 08, 2018, 08:41:20 AM
Adding animated ECMWF forecasts for 20mb and zonal mean winds to that hindcast in #794.
Title: Re: The 2017/2018 freezing season
Post by: Jim Hunt on February 08, 2018, 11:10:57 AM
The plunge in sea ice concentration poleward ... we'll have to wait and see if those hold up as AMSR2 can display a lot temporary weather artifacts (eg when the center of a cyclone passes over).

It's still looking distinctly dodgy on the latest AMSR2 update. See also Thomas Lavergne's sea ice drift animation:

http://GreatWhiteCon.info/2018/02/the-february-2018-fram-strait-cyclones/#Feb-08
Title: Re: The 2017/2018 freezing season
Post by: A-Team on February 08, 2018, 12:11:59 PM
Quote
It's still looking distinctly dodgy on the latest AMSR2 update
There are both conserved ice features and weather artifacts on the AMSR2 3.125 km over the last three days of the storm, in addition to lee polynyas around the islands and lift-off north of SZ. (The mp4 shows heal-and-seal plus passing weather effects for the last 160 days.)

We'll need the Feb 8th and 9th to assess the new damage appearing on the 7th. Which is better done on Sentinel-1AB orbital swaths with time stamps. We're always looking for consilience on the source side.

The question is whether it matters. The damaged ice is mostly poised for Fram export anyway over the next month so won't be around for melt season. The darker tongues originated in late October from the Kara and Laptev and so do not represent export of older thicker central or CAA ice, though there will be more of that this week.

Quote
See also T Lavergne's sea ice drift animation
Those are hosted at OSI SAF; Lavergne's five sea ice motion papers are listed at the bottom link below. They're 48-hour interval ice drift products posted from 2016 to the present. The scaling is 3x literal displacement, purple arrows are nearest neighbor interpolation; the hollow-core arrows seem to denote scale-exceeding. Oceans are colored as closed ice, open ice (good idea) and open water.

That means an arrow extending a full 62.5 km grid cell spacing length corresponds to a drift of 20.8 km or distance between the start point and stop point after 48 hours. These grid points are conveniently built into the map as even 0 velocity gets a point. The two-day thing is a bit awkward on the overlap, eg 04-06 followed by 05-07. The storm overwhelmed the scaling system but we can always fix that in Panoply.

The 2x image is new to 2018. LR-drift means low resolution, SSMIS (91 GHz, DMSP F17), ASCAT (Metop-B), and AMSR-2 (18.7 and 36.5 GHz, GCOM-W1). Extraordinary job of annotating the product, see 3rd link below.

They also offer a medium resolution daily based on 1 km AVHRR channel 2 (Metop-A VIS) and channel 4 (Metop-A TIR). It also is offered as a netCDF, meaning we could easily auto-process the whole set into a single animation as described on DevCorner. We've also made these products here using SIFT etc on ImageJ. Panoply will pull out the velocity distribution, averages, and extremes.

http://osisaf.met.no/p/osisaf_hlprod_qlook.php?year=2018&month=02&day=01&prod=LR-Drift&area=NH&size=100%25

http://osisaf.met.no/p/ice/#mrdrift

http://osisaf.met.no/p/ice/lr_ice_drift.html

ftp://osisaf.met.no/prod/ice/drift_lr/merged/  netCDF archive
Title: Re: The 2017/2018 freezing season
Post by: Nightvid Cole on February 08, 2018, 04:31:03 PM
Unfortunately, I can't do images on my computer right now, but take a look at Climate Reanalyzer. The Arctic is ground zero for an absolute blowtorch starting within the next few days!!!!
Title: Re: The 2017/2018 freezing season
Post by: Neven on February 08, 2018, 05:01:45 PM
Unfortunately, I can't do images on my computer right now, but take a look at Climate Reanalyzer. The Arctic is ground zero for an absolute blowtorch starting within the next few days!!!!

Yes, a 6.4 °C anomaly is quite something. Here's the mp4:

http://pamola.um.maine.edu/wx_frames/gfs/arc-lea/t2anom/mp4/gfs_arc-lea_t2anom_2018-02-08-00z.mp4
Title: Re: The 2017/2018 freezing season
Post by: Alexander555 on February 08, 2018, 07:28:06 PM
What would be the impact of this on the arctic ?

https://watchers.news/2018/02/08/warnings-issued-as-sudden-stratospheric-warming-threatens-europe-with-big-freeze/
Title: Re: The 2017/2018 freezing season
Post by: gerontocrat on February 08, 2018, 07:53:01 PM
What would be the impact of this on the arctic ?

https://watchers.news/2018/02/08/warnings-issued-as-sudden-stratospheric-warming-threatens-europe-with-big-freeze/
If your link connects with Neven's post above, this non-expert guess is while Europe (and Northern Canada ?) freezes the Arctic warms - a lot, (especially on Atlantic half ?). But wait for the guys who really know.
Title: Re: The 2017/2018 freezing season
Post by: uniquorn on February 08, 2018, 07:58:06 PM
Worldview 8th Feb Brightness Temperature(Band15, Night)

Nares Strait bottom left.
Title: Re: The 2017/2018 freezing season
Post by: Niall Dollard on February 08, 2018, 08:58:50 PM
What would be the impact of this on the arctic ?

https://watchers.news/2018/02/08/warnings-issued-as-sudden-stratospheric-warming-threatens-europe-with-big-freeze/

That's a very badly written article I'm afraid.

Firstly SSWs in general, are not that rare.

It then says " hasn't occurred since 2010 when it brought coldest March for 51 years to Scotland."

I imagine they are trying to refer to the year 2013. March 2010 saw just average temperatures in Scotland.

Back in early Jan 2013 there was a substantial SSW event followed by the usual media circus throughout Europe of impending severe cold. Jan and Feb passed. The extreme cold weather occurred over far to the SE of Europe over Kazakhstan, the Southern part of Russia and the Northwestern part of China during mid-January 2013. Finally in March 2013  there was a strong blocking Scandanavian High which gave many European countries (including Scotland) cold weather.

It is stretching things to say this blocking high was the downstream result of events back in early Jan 2013.

The one thing I would agree with in the article is where they say the "process won't take place overnight as it usually takes 10 to 25 days to form (down in the troposphere) and there is still uncertainty of how things will develop." 

2 to 4 weeks. Not two months. The UKMO in their analysis of 2013 event mention the SSW was only one of many contributory factors.

Back to 2018. It is pretty much on the cards now for an SSW event. But what will that mean for us landlubbers down in the troposphere (and more relevant to this forum - what will it mean for the Arctic Sea Ice ?

It is too soon to look for guidance from the medium range models and from what I have seen so far the longer range models are a bit all over the place - sometimes showing a Scandanavian High, sometimes just more of the status quo.

So a lot of uncertainty. With SSW events there are few definites as to where the HP will locate, where the blocking will occur - if even at all.

In the medium term the big Fram storm earlier this week has circulated a lot of mild Atlantic air deep into the Arctic and more to come it seems (Bering side looks mild too).

But when looking at a big overall picture like the DMI N80 mean temp (which I expect will keep very high for several days now), the more specific temps for a smaller zones may go unnoticed.

Looking at Jim Hunt's images, the ice is particularly fragile now in the area to the NE of Svalbard over to the Franz Josef land. But at least the medium term forecast for FJL from yr.no this evening is not all doom and gloom. It shows temps recovering there as we start next week with east winds delivering temps 10 C colder than now.  Still probably above normal (whatever that is now?) but likely as good as we could hope for.
Title: Re: The 2017/2018 freezing season
Post by: A-Team on February 08, 2018, 10:22:53 PM
Nice spotting, uniquorn.

Looks like the Fram is starting a receding arch collapse like we see so often for the Nares. The dotted periphery is about two-thirds of the way to north pole, about 300 km short. The Kara ice finger now reaches well inside the arc but on the right-hand side obscured by weather.
Title: Re: The 2017/2018 freezing season
Post by: Ice Shieldz on February 08, 2018, 10:27:37 PM
GFS 2-Meter mean temp anomalies. 1st is 7 day forecast. 2nd is Feb. mean to date (Feb. 1st through the 8th). The Chukchi and Barents seas continue their anomalous warmth that we've seen relatively persistently through out the freezing season. Doesn't bode well for these regions in terms of how they stand up to melting mechanisms and negative feedbacks associated with the resultant lower extent, sea ice thickness, etc.  Hopefully we see an abatement in the 7-Day trend of heat invading more of the central pack. However with the PV split, the odds of that kind of heat invasion increase.
Title: Re: The 2017/2018 freezing season
Post by: Neven on February 08, 2018, 10:31:20 PM
Anyone interested in reading more on SSWs, here's an ASIB guest blog post from 2013, written by Randall Gates: Sudden Stratospheric Warming Causes & Effects (http://neven1.typepad.com/blog/2013/04/sudden-stratospheric-warmings-causes-effects.html)
Title: Re: The 2017/2018 freezing season
Post by: Niall Dollard on February 09, 2018, 01:38:17 AM
Hopefully we see an abatement in the 7-Day trend of heat invading more of the central pack. However with the PV split, the odds of that kind of heat invasion increase.

It often happens that an SSW event leads to a negative AO index. A negative AO would be better for the Arctic Sea Ice in general.

"Heat invasion" is more linked to a positive AO (which is what we have at present). 

Title: Re: The 2017/2018 freezing season
Post by: FishOutofWater on February 09, 2018, 02:49:28 AM
This polar vortex splitting event in February will not produce several months of subsidence over the pole as the major stratospheric warming of January 2013. This event doesn't completely destroy the vortex, it displaces it to North America. Air is likely to subside over northern Siberia. Northern and central Siberia may have 4 to 6 weeks of colder than normal weather.

Events that take place in February have lesser impacts than events in early January.

Read Judah Cohen's blog.

This event is associated with the strongest west Pacific MJO wave on record. The heating was in the tropical Pacific and Indonesian regions. This is an atmospheric wave driven event. Heating is caused by wave dynamics, not lifting air off of the cold desert in the middle of winter. The physics is brutal. The explanation given in the guest blog post is just plain wrong. The potential temperature of the atmosphere at 200mb high above the deserts of Asia is much warmer than the surface potential temperature. That's why Beijing has such bad smog in the late fall and winter months. Air near the surface cannot rise much because of strong inversions.

Anyway, this is going to be primarily a wave 2 splitting event, not a wave 1 sudden stratospheric warming event so even if you don't follow what I just said, this event has very different dynamics than the 2013 event which was a sudden stratospheric warming driven by wave 1.

I'm a geochemist, not an atmospheric physicist. However, I studied enough geophysics to know that the blog post on SSWs proposed a mechanism that is not compatible with basic physics.

Do not expect this vortex splitting event to be good for sea ice because the cooling effects are likely to affect the continents, not the Arctic ocean.

Below is an image of today's velocity potential anomaly. Green show areas of rising air. Red shows subsidence.

Below is a 3 day forecast of momentum flux driven by planetary wave 2. There's a very large momentum flux at 50º N. Note that wave number 2 is consistent with warm oceans/Arctic and cold continents.
Title: Re: The 2017/2018 freezing season
Post by: FishOutofWater on February 09, 2018, 03:02:15 AM
In March and April the CFSv2 model predicts enhanced subsidence over the far north Pacific. This forecast is consistent with the known effects of La Niña, perhaps enhanced by the event in the stratosphere.

This forecast subsidence pattern would not help sea ice thickening.
Title: Re: The 2017/2018 freezing season
Post by: jdallen on February 09, 2018, 04:51:59 AM
In March and April the CFSv2 model predicts enhanced subsidence over the far north Pacific. This forecast is consistent with the known effects of La Niña, perhaps enhanced by the event in the stratosphere.

This forecast subsidence pattern would not help sea ice thickening.
I will hasten to add... both 2007 and 2012 were either in or on the slopes of a La Nina.
Title: Re: The 2017/2018 freezing season
Post by: numerobis on February 09, 2018, 06:50:45 AM
Chilly across Nunavut for the past few days — some new daily record lows. That’ll thicken up the pressed garlic, along with a bunch of ice that will melt regardless.
Title: Re: The 2017/2018 freezing season
Post by: jdallen on February 09, 2018, 07:30:30 AM
Chilly across Nunavut for the past few days — some new daily record lows. That’ll thicken up the pressed garlic, along with a bunch of ice that will melt regardless.
It will, and unfortunately at this point a few days - even a few weeks - of record lows won't thicken the ice as much as we need.  Most of that ice is already 2-ish Meters thick, which means there's fairly considerable lag in the heat transfer.  Temps need to go down and stay down at around -30/40C for things to improve.
Title: Re: The 2017/2018 freezing season
Post by: FredBear on February 09, 2018, 01:07:00 PM
Hi numerobis, the weather reports at the Kimmirut page seem to have frozen at 19 January (the forecasts & photo still change). I have noticed the forecasts have been much colder than the averages would lead us to expect lately.
Title: Re: The 2017/2018 freezing season
Post by: El Cid on February 09, 2018, 01:21:19 PM
Anyone interested in reading more on SSWs, here's an ASIB guest blog post from 2013, written by Randall Gates: Sudden Stratospheric Warming Causes & Effects (http://neven1.typepad.com/blog/2013/04/sudden-stratospheric-warmings-causes-effects.html)

Thanks! That is just the thing I was asking about in "Stupid Questions"!
Title: Re: The 2017/2018 freezing season
Post by: numerobis on February 09, 2018, 06:42:28 PM
FredBear: you can get all the Environment Canada reports here:
https://weather.gc.ca/forecast/canada/index_e.html?id=NU

jdallen: Every little bit helps. Lower surface temps mean the ocean will start up with that much less heat content, even if there is a lag, so it'll melt more slowly in the "warm" season.

But that's for the Canadian Arctic. Siberia and Alaska are steaming, relatively speaking. And the cold spell, while persisting here in the East for another week, has been pushed out of Western Nunavut by a nice little storm (which is cancelling flights out of Cambridge Bay).
Title: Re: The 2017/2018 freezing season
Post by: romett1 on February 09, 2018, 08:49:24 PM
The Chukchi and Barents seas continue their anomalous warmth that we've seen relatively persistently through out the freezing season.
Looks like melting season and not freezing - Pacific side Feb 6 - Feb 8. Indeed, current models show warmth until at least Feb 19 over Bering and Chukchi.
Title: Re: The 2017/2018 freezing season
Post by: jdallen on February 09, 2018, 10:49:42 PM
The Chukchi and Barents seas continue their anomalous warmth that we've seen relatively persistently through out the freezing season.
Looks like melting season and not freezing - Pacific side Feb 6 - Feb 8. Indeed, current models show warmth until at least Feb 19 over Bering and Chukchi.
Retreat in the Bering does not surprise me, not one little bit.  There's plenty of heat just below the surface, which itself for the most part is near or above 0C.  Add in rising amounts of insolation, and the slash ice that is standing in for "pack" will vanish quite readily.
Title: Re: The 2017/2018 freezing season
Post by: Ice Shieldz on February 10, 2018, 12:37:10 AM
Wondering how much of the persistence of 2 meter atmospheric heat is tied to the fact that the waters are so much warmer? I'm not talking about how the lack of sea ice relates to larger synoptics that deliver atmospheric heat, but rather how the net effect of warmer water (even under the ice) locally contributes to persistent atmospheric heat anomalies?

Title: Re: The 2017/2018 freezing season
Post by: jdallen on February 10, 2018, 02:58:04 AM
Wondering how much of the persistence of 2 meter atmospheric heat is tied to the fact that the waters are so much warmer? I'm not talking about how the lack of sea ice relates to larger synoptics that deliver atmospheric heat, but rather how the net effect of warmer water (even under the ice) locally contributes to persistent atmospheric heat anomalies?
My reflex answer was "Yes", but thinking about it, I'm not so sure.

Where you have open water, I think the answer is somewhat yes, as the dynamic exchange with atmosphere will buffer temperatures via the huge reservior of heat available in ocean generally. There the factor is less to do with anything about higher water temperatures and much related to the simple fact there is open water.

Where ice is present, not so much, as ice seriously impedes heat flow.
Title: Re: The 2017/2018 freezing season
Post by: DavidR on February 10, 2018, 03:23:01 AM
Wondering how much of the persistence of 2 meter atmospheric heat is tied to the fact that the waters are so much warmer? I'm not talking about how the lack of sea ice relates to larger synoptics that deliver atmospheric heat, but rather how the net effect of warmer water (even under the ice) locally contributes to persistent atmospheric heat anomalies?
My reflex answer was "Yes", but thinking about it, I'm not so sure.

Where you have open water, I think the answer is somewhat yes, as the dynamic exchange with atmosphere will buffer temperatures via the huge reservoir of heat available in ocean generally. There the factor is less to do with anything about higher water temperatures and much related to the simple fact there is open water.

Where ice is present, not so much, as ice seriously impedes heat flow.

However ice doesn't form where there is heat. So part of the reason for a slow build up of ice in the Pacific is the increase in temperatures in the sea there as shown in the graph. I  have emphasized the effect of pacific water temperatures by listing the years according to the increase in sea ice from now to the maximum. 2014 had a large late increase in March reflecting the plunge in temperatures in that  month.

Title: Re: The 2017/2018 freezing season
Post by: jdallen on February 10, 2018, 03:50:08 AM
Speaking of... Over the nest week, GFS has temperatures consistently 5-10C warmer than normal over the Arctic almost in its entirety.

Heat over the Bering is particularly sharp, and the ice there is already in serious trouble.  Snapshot (somewhat fuzzy, but resolveable) from Worldview today below.
Title: Re: The 2017/2018 freezing season
Post by: aperson on February 10, 2018, 05:29:43 AM
That prompted me to check the other side of the Bering Strait. Holy fuck.

Top: Feb 4th bands 7-2-1
Bottom: Feb 9th bands 7-2-1
Title: Re: The 2017/2018 freezing season
Post by: gerontocrat on February 10, 2018, 09:27:57 AM
Wondering how much of the persistence of 2 meter atmospheric heat is tied to the fact that the waters are so much warmer? I'm not talking about how the lack of sea ice relates to larger synoptics that deliver atmospheric heat, but rather how the net effect of warmer water (even under the ice) locally contributes to persistent atmospheric heat anomalies?
My reflex answer was "Yes", but thinking about it, I'm not so sure.

Where you have open water, I think the answer is somewhat yes, as the dynamic exchange with atmosphere will buffer temperatures via the huge reservior of heat available in ocean generally. There the factor is less to do with anything about higher water temperatures and much related to the simple fact there is open water.

Where ice is present, not so much, as ice seriously impedes heat flow.

ice seriously impedes heat flow.

I am sure you are right, but my question is what impedes the heat flow, as the thermal conductivity of ice (and any snow on top) is greater than that of water. Is it because of wind and waves and turbulence assisting the process?
Title: Re: The 2017/2018 freezing season
Post by: gerontocrat on February 10, 2018, 10:35:54 AM
Sudden Stratospheric Warming - something going on this weekend

https://www.netweather.tv/weather-forecasts/news/8730-sudden-stratospheric-warming-this-weekend-but-what-is-it-how-will-it-affect-our-weather

I like this article from Netweather as it is full up caveats and uncertainties, and brings in the MJO,  Atmospheric Angular Momentum (AAM)  and La Nina, and the  Quasi-Biennal Oscillation (QBO), all of which seem to increase the possibility of high latitude blocking and a risk of nationwide (UK) sustained colder weather later this month.

Effect on the Arctic ? Another wait and see job.
Title: Re: The 2017/2018 freezing season
Post by: Jim Hunt on February 10, 2018, 10:41:16 AM
An interesting insight into CryoSat-2 sea ice thickness measurements from Stefan Hendricks on Twitter:

http://GreatWhiteCon.info/2018/02/the-february-2018-fram-strait-cyclones/#Feb-09
Title: Re: The 2017/2018 freezing season
Post by: A-Team on February 10, 2018, 01:21:42 PM
Quote
Thomas Lavergne's 48-hour sea ice drift products are hosted at OSI SAF https://tinyurl.com/y8bsc24m
The montage below shows 156 days of those from early Sept up to Feb 9th. The storms show up very clearly as dark blotches (from the longer black velocity vectors being consolidated by the 14x downscaling). The mp4 goes through these days one at a time. Less than 3% are traditional 'Beaufort Gyre&