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Messages - seaicesailor

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1
Arctic sea ice / Re: The 2017 melting season
« on: July 21, 2017, 09:36:33 PM »
<snip: Off-topic, and too many layers of nested posts. JP>

2
Arctic sea ice / Re: The 2017 melting season
« on: July 21, 2017, 08:54:55 PM »
<snip: Off-topic, argumentative, and contained too many layers of nested posts. JP>

3
Arctic sea ice / Re: The 2017 melting season
« on: July 21, 2017, 06:02:43 PM »
(... and I do think they are more accurate than the US navy for example.Those guys can't steer a boat without running into a lighthouse. :)  )
A helluva reason to opt for the DMI crap.

4
Arctic sea ice / Re: The 2017 melting season
« on: July 20, 2017, 08:05:12 PM »
A few days of rough stormy weather ahead in the Beaufort sea, it will get cooler (eventually) as almost the whole Arctic proper, however these storms may disperse the neatly formed pack of broken floes in Beaufort. Still 60-90 days of bottom melt there.
Detail of ACNFS drift forecast for this Sunday, a couple of storms like this might make the thing look really messy as in '15 and '16

5
Arctic sea ice / Re: Home brew AMSR2 extent & area calculation
« on: July 20, 2017, 07:57:24 PM »
Given the fragmented nature of the ice and the SST anomalies, I am amazed by the compactness and resilience of the Beaufort as compared to last year.

I have to believe that this compactness serves to protect the ice.
Watchig the weather forecast, there may be a couple of small storms passing just over the Beaufort, if it happens as 2015 and '16, they can be pretty disruptive. Still 60-90 days of bottom melt ahead in the Beaufort sea.

6
Arctic sea ice / Re: Home brew AMSR2 extent & area calculation
« on: July 19, 2017, 09:49:23 PM »
Ice in about all possible NW passages turns mobile.
I also note Beaufort ice being driven south back across astonishingly warm water.  That won't be good for it.
Exactly, compared to other years where some storms scattered the ice, this year the pack at Beaufort is staying so neatly compacted (yes, it can be fragmented and compacted simultaneously), any dispersion now won't do any good there

7
Arctic sea ice / Re: The 2017 melting season
« on: July 19, 2017, 08:35:12 PM »
I had removed my original comment, I was thinking it didn't add anything new. Anyway I'll just say the NSIDC compactness (derived from Wipneus processed data, I believe) support, for me, what I could perceive from the Canadian Servive composite images of a colder state of the Arctic ice pack in general compared to 2012.
See oren's gif and comment here
https://forum.arctic-sea-ice.net/index.php/topic,1834.msg121401.html#msg121401

8
Arctic sea ice / Re: Latest PIOMAS update (mid July update)
« on: July 18, 2017, 02:56:59 PM »
Nice. Thank you Oren!
The weather vs thinness "game" ain't over till it's over.

9
Arctic sea ice / Re: IJIS
« on: July 17, 2017, 05:32:36 PM »
As I expected, the trend is now showing early signs of a slower decrease rate. The synoptic configuration for the next 7-10 days is definitely not bad for the ice. Yet, if confirmed by the next few runs, it would lead in my opinion to a further flattening of the curve. The maps are quite interesting indeed: persistence of LP systems in the absence of too big gradients. In other terms, conditions conductive to ice scattering and preservation due to cloudy skies, some precipitations and no inflow of warm winds from lower latitudes....
...
The chaps on the 2017 melting season thread have a totally contrary view on the way things are going. I also have looked at various weather sites and have seen nothing to tell me that climatic conditions are going to change soon to promote increased melting.
I agree here

10
Arctic sea ice / Re: The 2017 melting season
« on: July 17, 2017, 01:06:32 AM »
But this forecast could change again tomorrow morning. Either way, high pressure over Beaufort, Chukchi, ESS, Laptev and Kara is going to mean bye-bye for a lot of ice.
Thx for the forecasts, despite the highs, I think this circulation with such depression over Greenland is sparing the coup de grace to the entire Pacific side, that really looks like horrible. What would have been of it with a mild persistent dipole, or with a train of moderate storms like last year.
But we' ll see, the weakness of this thin FYI is showing anyway.

11
Arctic sea ice / Re: Home brew AMSR2 extent & area calculation
« on: July 16, 2017, 12:05:45 PM »
Wow the Chukchi sea decay...is the "soup" just melting in situ? ?

12
Arctic sea ice / Re: The 2017 melting season
« on: July 15, 2017, 08:51:04 PM »
It looks like the Atlantic front is really starting to melt now, whether by direct insolation or SST's, not to mention the warm surface breeze coming up to meet the ice edge.
Being just pushed too.

13
Arctic sea ice / Re: The 2017 melting season
« on: July 15, 2017, 08:49:41 PM »
I wonder how much of all that solar heat accumulated at Beaufort-Chukchi-ESS is actually melting ice. With the current conditions, I think very little. There is no strong air advection to bring it over it, no strong storm to disperse ice on these seas. But well, that could change anytime.
Chukchi sea is different, as has been noted one can see some swirls get very far into the pack or what has been calked the "soup" or the "rubble" north of Chukchi and ESS.

14
Arctic sea ice / Re: The 2017 melting season
« on: July 13, 2017, 10:16:07 AM »
Big jump in Slater's projection.... Now predicting 5.19m on August 31st.

Did his model just predict the melt season will end in August?  :o
Because NSIDC compactness has had a huge rebound and this model is all based on concentration.
Indeed this really smells like a rebound year itself, and with that cyclonic circulation around Greenland.
We'll see, all peripheral seas are for sure compromised, but I suspect the progress will slow down when reaching the CAB. Area got a bit of a mini-cliff before, but now in terms of anomaly it recovered to just over -1 million, see last Wipneus entry on NSIDC data

15
Arctic sea ice / Re: The 2017 melting season
« on: July 12, 2017, 10:22:16 AM »
What doesn't seem transient is the very anomalous depression over Greenland. It is enormous and will stay put, big change.

16
Arctic sea ice / Re: What the Buoys are telling
« on: July 11, 2017, 02:51:10 PM »
2017 A reports 21 cm of surface melt, almost entirely during last week, and about 19 cm of bottom melt. Almost 40 cm gone in 10 days!, the ice is now 79 cm, thinner than at deployment. At this rate the ice surrounding the buoy wont see August.

Unfortunately, currently away, cannot do the profile animations, for a nice while. :-(

Edit, interesting to observe the rate of surface melting during this week,  this buoy has been literally "under the weather" in Chukchi sea, not the 24/7 sunny skies one could associate with accelerated melt, but humid warm winds with clouds and rain.

17
Arctic sea ice / Re: What the Buoys are telling
« on: July 11, 2017, 11:31:42 AM »
Could we be looking at the ice freeboard now, meaning it is not draining because it is inundated?

18
On the ASIF you probably need to snip the bottom 10 percent to get a good predictive average for the current year. But one of these years these 10% will be the only ones who were right.
That sounds like the "stopped clock" thing. What's the virtue in just making the same automatic prediction year after year until it's right?  Aren't we supposed to be trying to learn something here?
Yes, but 2015 and 2016 I (or many) sort of got a consistent idea of what was going on and the predictions were not bad.
This year I still debate internally whether it is a 3 or a 5.. The first digit I mean.
I guess we will learn a good lesson from this season but it will be past September

19
Arctic sea ice / Re: The 2017 melting season
« on: July 10, 2017, 07:46:07 AM »
A peek through the clouds today at a roughly 100 km x 100 km area at the edge of the Chukchi ice vs. the same area a week ago.

The extent edge here has not moved, but ...
Looks really thin. Those fingers of open water intruding in the pack are very well defined.
Also the front has not moved but the ice has. The floe that is visible 20 km into the pack on the 2nd, I think it is now smaller, right at the edge

20
Arctic sea ice / Re: Arctic Image of the Day
« on: July 09, 2017, 10:56:55 PM »
Beautiful view of a cyclone over the Hudson bay from space today

21
Arctic sea ice / Re: 2017 sea ice area and extent data
« on: July 08, 2017, 06:58:01 PM »
All this with a 982 hPa in the middle of it all... impressive.
Compactness definitely down, leaving 2013/2014 league, next days most interesting

22
Arctic sea ice / Re: The 2017 melting season
« on: July 08, 2017, 01:59:42 PM »
The plume of humidity and rain from the Pacific that the storm has digested has left a clear mark of lowered concentration in the latest Uni Bremen maps, from ESS to Beaufort, after the previous day that the concentration seemed to recover. Some cooling follows the storm, then we have the somehow ominous forecasts written above. Def not uneventful.
Laptev sea is very damaged as well from previous days. That bite is almost 80N.
Not to mention the roasting of Barents and Kara
@Neven thank you for the SST maps.

Edit. Just noted from the animation that the "istmus" of ice attached to Alaska has been shrinking extremely fast these last three days. I attach a detail using Uni Hamburg AMSR2 maps this time

23
Arctic sea ice / Re: The 2017 melting season
« on: July 07, 2017, 10:52:11 PM »
Per discussion of Kara ice, it's gotten noticeably darker in the past couple days. Via worldview.

Edit: needs a click now, since I couldn't figure out how to resize it and still have it play on a loop.

Observing that dark ice with the "microscope" of the sentinel hub tool
http://apps.sentinel-hub.com
 i think is so thin it lets see thru to the ocean beneath

24
Arctic sea ice / Re: The 2017 melting season
« on: July 06, 2017, 11:25:46 PM »
ECMWF and GFS both point to pretty strong (I think, I'm new, so correct me if I'm wrong) dipoleish setup in 4-5 days.

Edit: Screenshot is 120hr, but it starts around 96.
It is a dipole in the sense of pairing a high and a low with strong pressure gradient between, but the Arctic dipole often mentioned here would see the high laying more over the American side, and the low or lows sitting over ESS/ Laptev/Kara, creating wind pattern that crosses the Arctic, transports warmth from the Pacific and the continents inside the Basin, and drifts ice fron the Pacific side toward the Atlantic. Somehow this has been a persistent story this year, only that weak and very gradual (imho).
Also that depression over Greenland in the forecast in general has not been typical of this spring/summer, and to me it does not promote the mentioned circulation. Quite the opposite
It is a "quadripole" ha! If that exists. Only that the forecast changes very quickly

25
comparing Bremen maps, and there is no year as "dark" in the Arctic proper as 2017
The color palette on the Bremen concentration maps has changed slightly this year.  There is no longer a lighter color for areas of just under 100% concentration.
Well that's a major mistake from my part then..., and well, they could have left the thing untouched.
Thank you for the notice!

26
Arctic sea ice / Re: What the Buoys are telling
« on: July 06, 2017, 05:50:12 PM »
At these rates, I strongly doubt the floe survives the summer. And all of this is happening as the buoy is heading north, into the CAB heartland.
I am afraid that it will not last much, too. With the rough weather taking over we'll see what it shows next week.

27
Arctic sea ice / Re: The 2017 melting season
« on: July 06, 2017, 05:42:31 PM »
I think the bering steamhose is raining out heavily and drawing down the condensation energy with the rainfall to sprawl out over the whole pacific quadrant.
The Bering Steamhose is clearly evident in the Precipitable Water gif from the ASIG.
Well whatever the outcome, this seems a concentrated but powerful event. I wonder how long the ice under the rain is going to last afterwards.
Pure speculation, but can the storm of the next few days pick its strength from this injection of humidity?

28
Arctic sea ice / Re: What the Buoys are telling
« on: July 06, 2017, 11:44:58 AM »
Update from our blind friend 2017A
The www reports 98 cm of thickness, with 9 cm of surface melt and 21 cm of bottom melt accumulated; melting has accelerated dramatically in the last week for obvious reasons.
Looking at the plot I would say there is more melt at both ends, but as others indicated before, drainage from the top, and direct heating from the sun may produce these results. Vertical displacement of the buoy might also have happened making the reference of the plots invalid.
The bottom water dramatically warms up to close to -1C, I suspect most probably to effect of drained water from the surface, since it seems to happen almost simultaneously along the whole column (however, on second look there seems to be a faster raise of temperature at the depth = 100 cm and around, which is just below the ice. Algae heating up? Fresher warmer water from the top just accumulating?)

29
Arctic sea ice / Re: Latest PIOMAS update (July)
« on: July 05, 2017, 12:17:08 PM »
Truth be told, if one looks at the volume anomaly from July onwards, 2012 is not outstanding, (not in its value itself which is outstanding, but in its evolution to becoming less anomalous):
https://forum.arctic-sea-ice.net/index.php/topic,119.msg119288.html#msg119288

Don't ask me why though

I am no expert but if what you are saying is that from July onwards, 2012 lost a lot of extent but not an anomalous amount of volume then my take would be that it latterly lost a large area of very thin ice, leaving the thicker core relatively normally affected.  That way the extent declined heavily but the volume declined normally.  Does that make sense?

Other than that it could just be inaccurate volume measurements. 8)
Yes makes sense to me that much of the ice that was gone in September 2012 had already thinned considerably by July. Given the crazy May/June 2012 ...

30
Arctic sea ice / Re: Latest PIOMAS update (July)
« on: July 05, 2017, 11:46:03 AM »
Truth be told, if one looks at the volume anomaly from July onwards, 2012 is not outstanding, (not in its value itself which is outstanding, but in its evolution to becoming less anomalous):
https://forum.arctic-sea-ice.net/index.php/topic,119.msg119288.html#msg119288

Don't ask me why though

31
Arctic sea ice / Re: The 2017 melting season
« on: July 04, 2017, 11:30:32 PM »
The weather in the Arctic changes, dominated in the next five days by cyclones on the CAB. I just cropped a map of ensemble ECMWF SLP, averaged for the next five days. Resembles now the pattern around the 3rd week of July 2012, which not surprisingly came with just around average decline of extent.
ACNFS forecasts dispersion of the ice pack toward open water areas of the Pacific side especially Beaufort sea.
Not all good news for the ice since it will be meeting the heat accumulated in these waters during the last month of sun and lately warm air.

32
Arctic sea ice / Re: The 2017 melting season
« on: July 03, 2017, 11:39:55 PM »
SST anomaly on July 1st, 2012 vs 2017:
Than you Neven, by any chance do you keep  2007 charts?

33
Arctic sea ice / Re: The 2017 melting season
« on: July 03, 2017, 06:44:38 PM »
At the same time, seems pretty sunny today from Beaufort sea to ESS
SST anomalies in these regions kinda going thru the roof

34
Arctic sea ice / Re: The 2017 melting season
« on: July 03, 2017, 05:24:31 PM »
The weather did a number on the pack didn't it?
One or two days more of warmth in the Pacific side, then not clear how it goes, if anybody cares to comment...
For sure winds will be blowing from the Pacific over the Bering almost 24/7
Edit, this is how windy.com depicts the current conditions, furnace-ous
https://on.windy.com/8t02
Edit2, save some steam these days to enter the Arctic across the Bering strait

35
Arctic sea ice / Re: Arctic Image of the Day
« on: July 02, 2017, 07:35:07 PM »
Nice!!
For comparison, this is what Worldview shows in the same location and day.
With the new tool, some discussion whether that is "garbage ice" or slush or not will be more easily solved (or will it create some more). https://go.nasa.gov/2uyO8bY

36
Arctic sea ice / Re: The 2017 melting season
« on: July 02, 2017, 05:03:23 PM »
Just saying, 2017 has been leading volume-wise in the inner basin, the CAB and adjoining areas, where differences in thickness manifest themselves as 2d area differences mainly in August. So it's a bit early to judge.
The main question mark of this stage will be resolved very soon with the end-June PIOMAS data. If the lead is preserved, the race is still on. Should the volume lead crumble to dust in the inner basin, 2017's chances for top finish will crumble as well.
Completely agree. There's still the argument that the remaining ice in the Pacific half is almost exclusively FYI, but even when it melts and fragments faster than MYI (for reasons completely different to what I thought, I must say), all depends on freak events to melt the same volume of ice as 2012. And the season so far weather wise is being bad for the ice but not that freaky

37

49 so far / 51 to come is the average of the last 10 years (2007-2016). If it does not add up my spreadsheet is stuffed. Just checked - my table starts with rows for each year as follows
 Max
 Min
June 30 melt
 Remaining melt
 Total melt
 Control - all nicely zero.

And no data I have says that a new record minimum is likely.
Thanks for the clarification.
Still, if the 2017 maximum was around 13.8 - 13.9 million km2 (not sure of the exact number) with slightly above 10 million km2 of total melt you should get something around 3.8 - 3.9 million km2.
Coincidentally it is within the range I have just selected

38
Not sure why you picked 49%, numbers seem to vary a lot, meaning a 52/48 proportion leads to a substantially different result to a 49/51.
But in any case, shouldnt the final result be like one million lower? I think it doesn't add up

39
Arctic sea ice / Re: 2017 sea ice area and extent data
« on: July 02, 2017, 03:13:57 PM »
9,244k is almost a double century...

40
Arctic sea ice / Re: The 2017 melting season
« on: July 01, 2017, 07:32:13 PM »
Meteorological resources really have a serious issue with metadata. ECMWF additional parameters are like golddust, yet a simple google search would yield absolutely nothing. Do you know any other cool websites? I suppose the UKV is a little too much to ask for?
Mmm I am not sure if I follow...
The one I indicated is more like nullschool. I don't know of more serious meteorological sites showing ECMWF surface temps.


41
My vote was 4-4,5 Mn km2, mostly due to lack of melt ponds.
Really agree on the lack of melt ponds. Just checked the ASIG page (courtesy of Neven of course) comparing Bremen maps, and there is no year as "dark" in the Arctic proper as 2017, only equaled by 2009 (and then back to 2005).

https://sites.google.com/site/arcticseaicegraphs/concentration-maps/sic0701

Note: Uni Bremen has changed the palette in their maps (it will show as obscure as 100% for a small range near 100%) and as such one cannot compare small loss of concentration with previous years anymore... thanks to sezlobs for noticing it


Of course these are one-day comparisons, but says a lot. Sustained widespread surface melting should show in a one-day map too!

 

42
Arctic sea ice / Re: The 2017 melting season
« on: July 01, 2017, 06:56:06 PM »
Apologies, can I ask how you managed to find this resource? I've been looking for ECMWF additional parameters for ages. Best I could come up with was the glitchy wundermap which worked about 20% of the time.


The page is
https://www.windy.com/

It was brought here the other day with a lot of nice examples:
http://forum.arctic-sea-ice.net/index.php/topic,1834.msg118051.html#msg118051


43
Arctic sea ice / Re: The 2017 melting season
« on: July 01, 2017, 02:20:41 PM »
I did some gif using windy.com for the next 5 days, which uses ECMWF for temperatures rather than the unreliable GFS. Sorry for the quality of the images, the converter I use is crappy. The scale of temperatures wouldn't fit, has to be consulted in windy.com directly. 
The advection of warm air affecting the surface is continuous through Bering Strait and ESS, also Beaufort and CAA. Note how warm the main NWP stays these days.
Temperatures do not go up much within the Arctic proper. I'd say that is expected over ice. These tongues of warmer air sufficiently far from the coast typically go up to 2 to 3 degrees, not more.
That does not mean that heat is not being transferred. It is, from turbulent mixing of warmer airmass from higher altitudes, and from radiation in general. Actually 3 degrees over the CAB, as closed pack as it is now, strikes me as pretty warm.
"Night" temperatures stay barely over zero across all the Pacific side, negative in other locations.

44
Arctic sea ice / Re: The 2017 melting season
« on: July 01, 2017, 12:32:58 AM »
Is it possible that the big discrepancy between the eastern Arctic, especially Greenland, and the western Arctic, that means the Pacific side, plays a role in the low temperature average? The Pacific side definitely is not cold at all, while the Atlantic side rather destroys ice by export and storms and not so much by heat (but both sides seem to work hand in hand in a way ... ).
It's the wind that blows from the Pacific across the Pole, by then has become cold North wind, over Svalbard and Greenland, all thru the Arctic losing energy to melt ice and heat cold ice, plus the remnants of the past storm.
2007 is the paramount example of this kind of circulation sustained for months since spring and all thru July. Have a look to 2007 DMI temps... Mostly negative anomalies for months. The year of so bad pacific side meltout.
DMI 80 N is not clearly correlated with melting, period.
Said so LMV is all right in pointing really anomalous cold dip. We will see.

45
Arctic sea ice / Re: The 2017 melting season
« on: June 30, 2017, 08:23:00 PM »
I put together some Neven's SLP maps just to understand three different scenarios of weather for month of July ( 2014, 2012, and 2007)
The pressure pattern is not the whole story, but was hopeful of getting some clear picture of the differences.
Just for fun I add the latest EPS forecast averaged fron July 1 to 5, resembles to second week of July 2007

46
Arctic sea ice / Re: What the Buoys are telling
« on: June 29, 2017, 08:08:48 PM »
Wasn't there someone here at the forum who is living at/near Resolute? Maybe he/she has some good info about the melt water sea :)
Wayne Davidson over the blog if Im not mistaken

47
Arctic sea ice / Re: The 2017 melting season
« on: June 29, 2017, 03:17:49 PM »
The ACNFS drift forecast for today and following 6 days

48
Arctic sea ice / Re: What the Buoys are telling
« on: June 28, 2017, 04:46:24 PM »
2017B had updated on the 20th too, I add the plots here.
Even though this buoy is closer to the North Pole, it had no snow on top, and so seems to have (one centimeter of) surface melt. Also 8 cm of bottom melt (185 cm of thickness). This is reported in the web page of the buoy.
http://imb-crrel-dartmouth.org/imb.crrel/2017B.htm

49
Arctic sea ice / Re: The 2017 melting season
« on: June 28, 2017, 12:26:13 PM »
I promise my last OT comment on this. I can imagine a thought scenario, unrealistic but not by much, where the Arctic melts out with negative TDD (say, a massive and unprecedented inflow of Bering water, for instance, combined with a high anticyclone with relatively cold temperatures but sun radiation helping the ocean current in bottom melting the ice).
However I cannot imagine a weak winter without low FDD

Add storm effects to enhance ice melting. All that is elusive to the Thawing DD. Just saying.

50
Arctic sea ice / Re: The 2017 melting season
« on: June 28, 2017, 09:45:55 AM »
Latest thawing degree days: [from http://sites.uci.edu/zlabe/arctic-temperatures/]



With all due respect, I am not sure what kind of information one can extract from the thawing dd. It is influenced by things other than an indication of thawing, like:
- Proportion of first year ice vs. multi-year ice
- In summer, change in circulation pattern affect temps often in ways that, although it may seem the main pack is around freezing temps, the periphery area and extent are plummeting.

And it misses a few:
- Heat absorption from direct insolation (insolation, as AndreasT pointed us several times, is not that well correlated with temperature and onset of surface melting; conversely, as Andreas pointed out too, can be causing direct melting beneath the ice by heating algae, bottom water, the ice itself)
- Heat transfer by rain, or humidity effects,
- Heat transfer by whatever other means, ocean currents
- Mechanical effects of storms that may even induce a dip in the atmospheric temperatures but that in August are devastating in the marginal ice, churning down ice to smaller and smaller pieces until the last bits melt out at temperatures that may be even lower in average than in the 80's

And there is a certain, although very small, downwards trend in the DMI 80N 2m temp. especially in August for the recent years, possibly because of much less MYI in the Arctic, the equillibrium temperature of the melting ice is overall slightly lower. We would end up with lower valyes of thawing degree days or with diminished in the last stretch of the melting season in the 2010's ?

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