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meddoc

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Re: The 2017/2018 freezing season
« Reply #500 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.

Dharma Rupa

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Re: The 2017/2018 freezing season
« Reply #501 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.

aperson

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Re: The 2017/2018 freezing season
« Reply #502 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.

Wherestheice

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Re: The 2017/2018 freezing season
« Reply #503 on: December 26, 2017, 08:23:35 AM »
Hello fellow members. I just joined this forum. Just letting you all know i'm here :)

El Cid

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Re: The 2017/2018 freezing season
« Reply #504 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!

meddoc

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Re: The 2017/2018 freezing season
« Reply #505 on: December 26, 2017, 11:00:17 AM »
Just when u thought u were out of the water

Wherestheice

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Re: The 2017/2018 freezing season
« Reply #506 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.

Tor Bejnar

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Re: The 2017/2018 freezing season
« Reply #507 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!
Arctic ice is healthy for children and other living things.

Daniel B.

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Re: The 2017/2018 freezing season
« Reply #508 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.

aperson

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Re: The 2017/2018 freezing season
« Reply #509 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.

Clenchie

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Re: The 2017/2018 freezing season
« Reply #510 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!
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Thomas Barlow

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Re: The 2017/2018 freezing season
« Reply #511 on: December 29, 2017, 04:32:09 PM »
Closing in?

El Cid

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Re: The 2017/2018 freezing season
« Reply #512 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?

Dharma Rupa

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Re: The 2017/2018 freezing season
« Reply #513 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.

Jim Pettit

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Re: The 2017/2018 freezing season
« Reply #514 on: December 29, 2017, 05:47:08 PM »

Avalonian

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Re: The 2017/2018 freezing season
« Reply #515 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!

FishOutofWater

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Re: The 2017/2018 freezing season
« Reply #516 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.

aperson

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Re: The 2017/2018 freezing season
« Reply #517 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.
« Last Edit: December 29, 2017, 07:31:33 PM by aperson »

Thomas Barlow

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subgeometer

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Re: The 2017/2018 freezing season
« Reply #519 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

subgeometer

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Re: The 2017/2018 freezing season
« Reply #520 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.

« Last Edit: December 30, 2017, 05:31:55 AM by subgeometer »

Iain

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Re: The 2017/2018 freezing season
« Reply #521 on: December 30, 2017, 10:47:10 AM »

bosbas

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Re: The 2017/2018 freezing season
« Reply #522 on: December 30, 2017, 11:41:24 AM »
Iain, you should label your plot 12-25 as it lists values from few days back.

Iain

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Re: The 2017/2018 freezing season
« Reply #523 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/

gerontocrat

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Re: The 2017/2018 freezing season
« Reply #524 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.
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Pavel

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Re: The 2017/2018 freezing season
« Reply #525 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

Thomas Barlow

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Re: The 2017/2018 freezing season
« Reply #526 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/

gerontocrat

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Re: The 2017/2018 freezing season
« Reply #527 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 ?
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Re: The 2017/2018 freezing season
« Reply #528 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.
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Dharma Rupa

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Re: The 2017/2018 freezing season
« Reply #529 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.

gerontocrat

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Re: The 2017/2018 freezing season
« Reply #530 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.

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Tor Bejnar

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Re: The 2017/2018 freezing season
« Reply #531 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.  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'.)
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Thomas Barlow

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Re: The 2017/2018 freezing season
« Reply #532 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/

Shared Humanity

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Re: The 2017/2018 freezing season
« Reply #533 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.  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.

jdallen

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Re: The 2017/2018 freezing season
« Reply #534 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.
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A-Team

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Re: The 2017/2018 freezing season
« Reply #535 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.)
« Last Edit: December 31, 2017, 11:47:00 PM by A-Team »

Alexander555

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Re: The 2017/2018 freezing season
« Reply #536 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 ?

Dharma Rupa

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Re: The 2017/2018 freezing season
« Reply #537 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.

A-Team

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Re: The 2017/2018 freezing season
« Reply #538 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.
« Last Edit: January 01, 2018, 02:38:09 AM by A-Team »

subgeometer

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Re: The 2017/2018 freezing season
« Reply #539 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.  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

subgeometer

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Re: The 2017/2018 freezing season
« Reply #540 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

« Last Edit: January 01, 2018, 03:27:01 AM by subgeometer »

Tor Bejnar

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Re: The 2017/2018 freezing season
« Reply #541 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.)
Arctic ice is healthy for children and other living things.

A-Team

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Re: The 2017/2018 freezing season
« Reply #542 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

« Last Edit: January 01, 2018, 03:47:59 PM by A-Team »

Thomas Barlow

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Re: The 2017/2018 freezing season
« Reply #543 on: January 01, 2018, 04:37:12 PM »
Lincoln Sea and Nares Straight -Jan 1

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Re: The 2017/2018 freezing season
« Reply #544 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.
« Last Edit: January 01, 2018, 10:41:06 PM by Ice Shieldz »

A-Team

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Re: The 2017/2018 freezing season
« Reply #545 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/
« Last Edit: January 03, 2018, 12:29:09 AM by A-Team »

Thomas Barlow

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Re: The 2017/2018 freezing season
« Reply #546 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/
« Last Edit: January 04, 2018, 12:01:05 AM by Thomas Barlow »

Brigantine

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Re: The 2017/2018 freezing season
« Reply #547 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.

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Re: The 2017/2018 freezing season
« Reply #548 on: January 03, 2018, 10:20:10 AM »
Warmest/Least coldest December on record for 65-90N:
Il faut cultiver notre jardin

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Re: The 2017/2018 freezing season
« Reply #549 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
« Last Edit: January 03, 2018, 12:12:16 PM by gerontocrat »
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