Arctic Sea Ice : Forum

Cryosphere => Arctic sea ice => Topic started by: Freegrass on September 17, 2020, 02:41:55 AM

Title: The 2020/2021 freezing season
Post by: Freegrass on September 17, 2020, 02:41:55 AM
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I agree with Neven, it's time to make the switch. It's getting really cold up there...

Looks to me like it's safe to call the minimum.
Title: Re: The 2020/2021 Freezing Season
Post by: oren on September 17, 2020, 03:22:54 AM
Please continue posting in the melting season thread for a couple of days.
Title: Re: The 2020/2021 freezing season
Post by: be cause on September 17, 2020, 12:16:40 PM
perhaps we should have a ' melt , freeze or tease ? ' thread for these in-between days . It seems like this period .. within 100k sqkms of minimum , gets longer every year .. b.c.
Title: Re: The 2020/2021 freezing season
Post by: Shared Humanity on September 17, 2020, 03:49:13 PM
I am certain I will be a regular visitor to this thread throughout the freeze season. We need a good freeze season to avoid disaster next year IMHO. The Atlantic and Siberian sides of the ocean are scary.
Title: Re: The 2020/2021 freezing season
Post by: gandul on September 17, 2020, 08:04:57 PM
There’s no way we are back below the minimum by any consideration (weather, probability based on past years, ice state).
In fact I am surprised this thread could not be opened a week earlier.
Initial conditions: although SST are anomalously high in general, the Beaufort-(north of) Chukchi region looks more yellow than red, a large extent that could refreeze faster than last year until November at least.
Title: Re: The 2020/2021 freezing season
Post by: Gumbercules on September 18, 2020, 12:31:50 AM
There’s no way we are back below the minimum by any consideration (weather, probability based on past years, ice state).
In fact I am surprised this thread could not be opened a week earlier.
Initial conditions: although SST are anomalously high in general, the Beaufort-(north of) Chukchi region looks more yellow than red, a large extent that could refreeze faster than last year until November at least.

However, do you not think that we will be soon be below the record for each date soon? That seems likely. Sure, we didn't breach the 2012 minimum, but it seems likely we will breach the all time records for each given date shortly. If the freeze is even slightly slow we'll be under the all time minimums for a given date and unable to get above. 2012 had a fairly steep and steady incline after the low (which is also probably a result of having such a low low).
Title: Re: The 2020/2021 freezing season
Post by: I’M IN LOVE WITH A RAGER on September 18, 2020, 05:12:46 AM
First signs of large-scale refreeze in the Beaufort tail?

Siberian edge and the interior CAB still looking kinda rough though wow

Edit: JAXA certainly seems to agree with that century gain today
Title: Re: The 2020/2021 freezing season
Post by: jens on September 18, 2020, 10:01:11 AM
I am certain I will be a regular visitor to this thread throughout the freeze season. We need a good freeze season to avoid disaster next year IMHO. The Atlantic and Siberian sides of the ocean are scary.

Last winter was surprisingly cold in the sense that in the beginning of the year 2020 was lingering around 10th position in extent for a while. Not sure how likely it is to get two consecutive winters like that in a row.
Title: Re: The 2020/2021 freezing season
Post by: El Cid on September 18, 2020, 12:26:49 PM
Last winter was surprisingly cold in the sense that in the beginning of the year 2020 was lingering around 10th position in extent for a while. Not sure how likely it is to get two consecutive winters like that in a row.

I guess as likely as getting two red numbers in roulette in a row :)
Title: Re: The 2020/2021 freezing season
Post by: gandul on September 18, 2020, 01:02:27 PM
There’s no way we are back below the minimum by any consideration (weather, probability based on past years, ice state).
In fact I am surprised this thread could not be opened a week earlier.
Initial conditions: although SST are anomalously high in general, the Beaufort-(north of) Chukchi region looks more yellow than red, a large extent that could refreeze faster than last year until November at least.

However, do you not think that we will be soon be below the record for each date soon? That seems likely. Sure, we didn't breach the 2012 minimum, but it seems likely we will breach the all time records for each given date shortly. If the freeze is even slightly slow we'll be under the all time minimums for a given date and unable to get above. 2012 had a fairly steep and steady incline after the low (which is also probably a result of having such a low low).

My hunch was that there are these Pacific-side regions ripe for early faster refreeze. If that happens that makes what you say more improbable but not impossible.
Title: Re: The 2020/2021 freezing season
Post by: oren on September 18, 2020, 01:27:42 PM
The 2020/2021 freezing season has officially begun.
Title: Re: The 2020/2021 freezing season
Post by: Freegrass on September 18, 2020, 02:00:36 PM
The 2020/2021 freezing season has officially begun.
I wish I was as good with calling a bottom in the stock market then I am with calling a bottom in the arctic...  :-\
Title: Re: The 2020/2021 freezing season
Post by: Freegrass on September 18, 2020, 02:28:49 PM
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Title: Re: The 2020/2021 freezing season
Post by: Shared Humanity on September 18, 2020, 02:47:00 PM
Sure looks like the warmth on the Atlantic and Siberian sides does not want to surrender quietly. This is where the freeze season will be most riveting.
Title: Re: The 2020/2021 freezing season
Post by: BornFromTheVoid on September 18, 2020, 04:24:24 PM
Here's a quick summation of the 2020 melt season, at 2 week intervals. Max extent was around the March 4th, while min seems like Sept 13th (so the final period is not quite 2 weeks!).

I should probably mention the top one is an animation. Click to play!
Title: Re: The 2020/2021 freezing season
Post by: anaphylaxia on September 18, 2020, 04:42:19 PM
Wow, excellent representation of the whole season!
Title: Re: The 2020/2021 freezing season
Post by: Wildcatter on September 18, 2020, 04:44:19 PM
I know one thing, a winter season like last year with a strong polar vortex low-pressure dominated, would not be ideal.
Title: Re: The 2020/2021 freezing season
Post by: gandul on September 18, 2020, 04:51:00 PM
Why not? If it’s not beacause of 2019 Winter, 2020 would have broken 2012 record.

Also I notice from the PIOMAS thread maps from winter+sprint, that last winter’s weather pattern induced an anomalously anemic Beaufort  Gyre drift very limited in extent too, even accumulating some ice apart from turning ice around, explaining the extra thickness and resilience of sea ice there this year.

Taken from a post by Oren:
Title: Re: The 2020/2021 freezing season
Post by: nanning on September 18, 2020, 04:53:56 PM
Bravo Samuel, beautiful. Thanks for all your efforts! :)
What ana says.
Title: Re: The 2020/2021 freezing season
Post by: Freegrass on September 18, 2020, 06:55:18 PM
I know one thing, a winter season like last year with a strong polar vortex low-pressure dominated, would not be ideal.
If the arctic freezing season resembles anything like the antarctic freezing season, then we could be in for a big surprise.

Less pollution and fewer contrails will keep the skies open for a big cooldown?
Title: Re: The 2020/2021 freezing season
Post by: jai mitchell on September 18, 2020, 06:56:03 PM
I truly thought we would beat the 2012 minimum this year due to a massive decrease in global aerosol loading.  But we didn't.
Title: Re: The 2020/2021 freezing season
Post by: Freegrass on September 18, 2020, 07:05:43 PM
I truly thought we would beat the 2012 minimum this year due to a massive decrease in global aerosol loading.  But we didn't.
Same here... But we did almost beat 2012 without a GAC or Dipole, and the temperatures were record breaking in the arctic. So that theory isn't dead IMHO...

Let's see what winter brings!
Title: Re: The 2020/2021 freezing season
Post by: I’M IN LOVE WITH A RAGER on September 18, 2020, 11:05:23 PM
I do wonder if atmospheric aerosol levels have begun to rebound somewhat, since global traffic has picked up massively since mid-March. Does anybody have a good time-series data source to see how NO2 and SO2 have changed since then, along with the usual CO2 and CH4? Would be very interesting to see.

I also think it is also worth noting that Antarctica and the Arctic are two different animals, with 2014 setting the all time high extent record for the satellite era, and persistent cold anomalies around large areas of the eastern continent which do not seem to be present in the Arctic Circle (to the best of my knowledge, please correct me if I am wrong). As jens said earlier, I would be quite surprised to see a freezing season produce a greater peak extent than the 2019-2020 freezing season, especially with all the thermal energy in the seas above W Siberia. I’m sure the picture will becomes much clearer through Oct-Dec though, so I don’t want to make any definitive calls yet.
Title: Re: The 2020/2021 freezing season
Post by: Pavel on September 18, 2020, 11:42:20 PM
Last year the Laptev sea has delayed refreeze and there was still open water in early November. This year I think 2-3 more weeks at least to delay freeze up. The Kara sea is also very warm and it should take a long while until the heat would be lost. I hope at least the weather pattern won't repeat the 2016 autumn. But however the last winter caused low snow extent in Eurasia
Title: Re: The 2020/2021 freezing season
Post by: gandul on September 19, 2020, 12:34:07 AM
The green and blue regions in this map imo will refreeze fast.
Title: Re: The 2020/2021 freezing season
Post by: be cause on September 19, 2020, 02:04:20 AM
.. while the mustard continues to disappear ? b.c.

p.s. given winds may cause the region recorded as flash freezing yesterday to be 'thawed' by tomorrow .
Title: Re: The 2020/2021 freezing season
Post by: jdallen on September 19, 2020, 03:11:05 AM
I do wonder if atmospheric aerosol levels have begun to rebound somewhat, since global traffic has picked up massively since mid-March.<snip>

I also think it is also worth noting that Antarctica and the Arctic are two different animals
<snip>
Aerosol levels may have helped the melt by slightly increasing available insolation, their absence won't necessarily help the refreeze.  What has really affected that is the availability of moisture in the atmosphere, and advection (or the absence thereof) from lower latitudes.  It is hard to understate the importance of H2O as a greenhouse gas, and it's increase is a positive feedback of warming caused by increased CO2.

And yes, the northern and southern hemispheres are profoundly different.  The Antarctic suffers from nothing like the pollution issues the Arctic has, and as a "cold continent" the ice it has locked in is much better protected from heat.

There will probably be retreats by the Antarctic ice caps over the next few centuries, but unless CO2 spirals totally out of control (> 1000PPM), they will probably persist long after the Arctic ice and Greenland ice cap are memories.

Because of that, atmospheric circulation in the southern hemisphere will probably remain broken into three circulation cells.  It would be fascinating to see, but, none of us will live that long I expect.
Title: Re: The 2020/2021 freezing season
Post by: Positive retroaction on September 19, 2020, 09:03:19 AM
I do wonder if atmospheric aerosol levels have begun to rebound somewhat, since global traffic has picked up massively since mid-March.<snip>

I also think it is also worth noting that Antarctica and the Arctic are two different animals
<snip>

And yes, the northern and southern hemispheres are profoundly different.  The Antarctic suffers from nothing like the pollution issues the Arctic has, and as a "cold continent" the ice it has locked in is much better protected from heat.

There will probably be retreats by the Antarctic ice caps over the next few centuries, but unless CO2 spirals totally out of control (> 1000PPM), they will probably persist long after the Arctic ice and Greenland ice cap are memories.

Because of that, atmospheric circulation in the southern hemisphere will probably remain broken into three circulation cells.  It would be fascinating to see, but, none of us will live that long I expect.

Totally agree
Antarctica is a continent, it is not subject to the same melting mechanisms, and the damage is not seen with the same measurements
If we just look at the extent of the sea ice, this is not the biggest change
The pack ice is fed by ice from the continent
As long as there is a large volume of ice on the mainland, pack ice will continue to form
As the ice from the continent is sliding faster and faster towards the pack ice, the surface area of ​​the pack ice is not a big clue.
But the total volume of ice is interesting when you add pack ice and land ice.
We can see that the loss has been enormous for decades, and the loss is accelerating
In the arctic as we know, all the sea ice data is a representative mesure of the arctic health
In Antarctica sea ice is just a few part
https://www.pnas.org/content/116/4/1095 (https://www.pnas.org/content/116/4/1095)
So we can't compare arctic and Antarctica freezing, or deduce the future of arctic with the antarctic observations or experience
In blue anomaly
Red Glace loss
Purple total mass
Title: Re: The 2020/2021 freezing season
Post by: BornFromTheVoid on September 19, 2020, 12:22:22 PM
Today's images and animation. The gains in the Beaufort Sea have persisted, so more evidence that the minimum has been passed.
Title: Re: The 2020/2021 freezing season
Post by: Paladiea on September 19, 2020, 02:14:14 PM
Not sure if this is the relevant area to put this, but new paper out discussing increased bottom melt in the Arctic.

https://journals.ametsoc.org/jcli/article/33/18/8107/353233/Weakening-of-Cold-Halocline-Layer-Exposes-Sea-Ice

Weakening of Cold Halocline Layer Exposes Sea Ice to Oceanic Heat in the Eastern Arctic Ocean
Title: Re: The 2020/2021 freezing season
Post by: Freegrass on September 19, 2020, 02:14:44 PM
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Notorious Ravaging Big Gale
Title: Re: The 2020/2021 freezing season
Post by: Pagophilus on September 19, 2020, 06:53:56 PM
Not sure if this is the relevant area to put this, but new paper out discussing increased bottom melt in the Arctic.

https://journals.ametsoc.org/jcli/article/33/18/8107/353233/Weakening-of-Cold-Halocline-Layer-Exposes-Sea-Ice

Weakening of Cold Halocline Layer Exposes Sea Ice to Oceanic Heat in the Eastern Arctic Ocean
Seems very relevant to me.  Weakening of the halocline, halocline level approaching the base of winter surface mixed layer, doubling of the ocean upward heat flux in winter.  Disturbing stuff.
Title: Re: The 2020/2021 freezing season
Post by: Pagophilus on September 19, 2020, 07:10:57 PM
Worldview, ice edge N of FJL, today.
A question:  are those streamers of ice between the two red arrows?  If so are they streamers of melting ice?
I ask because I have often seen similar features at the edge of the ice when the ice is melting strongly in the spring and summer.  Is the same thing going on here along the Atlantic edge of the ice pack?
Title: Re: The 2020/2021 freezing season
Post by: BornFromTheVoid on September 19, 2020, 08:02:38 PM
Animation of the annual max and min, from 1979 to present (click to play).
Title: Re: The 2020/2021 freezing season
Post by: Stephan on September 19, 2020, 09:52:34 PM
Very nice animation. Thanks for all these great contributions.  :)
Title: Re: The 2020/2021 freezing season
Post by: D-Penguin on September 20, 2020, 01:45:50 AM
Animation of the annual max and min, from 1979 to present (click to play).
This type of synchronized animation that compares a particular metric with an outcome is visually powerful and instructive.

+1 Brilliant and instructive animation.
Title: Re: The 2020/2021 freezing season
Post by: VeliAlbertKallio on September 20, 2020, 04:53:36 AM
2020-2021 freezing season is important to observe because of high peripheral seas sunlight intake. What happens now will be in more extreme form next year if similar melt year is being repeated with ice recovery lacklustre and delayed. 2021-2022 melt season has already been predicted as potential repeat with jet streams locked by the end of 2021 to the latitude of the Gibraltar Strait. Expect delayed freezing much stronger with strong storms in Arctic with vast bigger lake-snow effect. Beasts of east to wipe across Northern and Central Europe, with unusual monsoon and wind patterns to be seen in Asia further south. Particularly interesting feature being the heavy rains to Morocco, Algeria, Spain, Portugal, south France. The Central Arctic Basin may make first moves towards central (polar) hole with re-freezing inversion from the periphery towards the centre of the Arctic Ocean (depending how much ice left on the pole).
Title: Re: The 2020/2021 freezing season
Post by: Aluminium on September 20, 2020, 11:40:15 AM
September 14-19.

2019 (https://forum.arctic-sea-ice.net/index.php/topic,2591.msg229814.html#msg229814).
Title: Re: The 2020/2021 freezing season
Post by: BornFromTheVoid on September 20, 2020, 12:11:21 PM
Latest images and animation. Ice gained in the Beaufort Sea over the previous two days has mostly disappeared now.
Will it return?
Title: Re: The 2020/2021 freezing season
Post by: Freegrass on September 20, 2020, 01:44:18 PM
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Title: Re: The 2020/2021 freezing season
Post by: BornFromTheVoid on September 20, 2020, 05:00:10 PM
By just following the average extent gain of the last 10 years, the 365 day trailing average will drop below 10 million km2 for the first time by the end of February.
Title: Re: The 2020/2021 freezing season
Post by: Niall Dollard on September 20, 2020, 11:51:39 PM
New ice formed over the open waters south of Mackenzie King Island overnight between 18th and 19th September.

Estimated area of about 4.2 km2. GIF needs a click to run.
Title: Re: The 2020/2021 freezing season
Post by: be cause on September 21, 2020, 02:15:15 AM
https://go.nasa.gov/3mDgI7M .. gateway to a winter wonderland .. I hope . Today at the North pole . b.c.
Title: Re: The 2020/2021 freezing season
Post by: The Walrus on September 21, 2020, 02:35:02 AM
By just following the average extent gain of the last 10 years, the 365 day trailing average will drop below 10 million km2 for the first time by the end of February.

I question the validity of a forecast so far beyond the trend line.
Title: Re: The 2020/2021 freezing season
Post by: Pagophilus on September 21, 2020, 02:47:47 AM
By just following the average extent gain of the last 10 years, the 365 day trailing average will drop below 10 million km2 for the first time by the end of February.
Strewth!  (Time to breathe into a paper bag)
Thanks, BFTV.  I think.   At first I thought there was some error, but then I realized your graph plummets so far because it goes on into 2022, and that would presuppose the current trend through 2019 and 2020 continues.  Which it could, especially if there is a poor refreeze, a possibility on many of our minds at present.  If so then that straight-line-looking decline trend, already scary, could start looking heart-stopping.
Title: Re: The 2020/2021 freezing season
Post by: oren on September 21, 2020, 08:26:59 AM
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It's interesting how the deep cold is squeezed away throughout the basin. This will not bring back the melting season but could considerably slow down the freezing season.
Title: Re: The 2020/2021 freezing season
Post by: BornFromTheVoid on September 21, 2020, 09:40:53 AM

I question the validity of a forecast so far beyond the trend line.


Strewth!  (Time to breathe into a paper bag)
Thanks, BFTV.  I think.   At first I thought there was some error, but then I realized your graph plummets so far because it goes on into 2022, and that would presuppose the current trend through 2019 and 2020 continues.  Which it could, especially if there is a poor refreeze, a possibility on many of our minds at present.  If so then that straight-line-looking decline trend, already scary, could start looking heart-stopping.

Only following the previous 10 years would produce 2 very low minima and a record low maximum, which is easy enough to envisage, though unlikely.
However, given that minima are falling at a much faster rate than maxima, it's reasonable to assume that gains will eventually accelerate to a faster rate than the 10 years average. A spread of the lowest 5 years will probably produce more realistic projections.
Title: Re: The 2020/2021 freezing season
Post by: BornFromTheVoid on September 21, 2020, 10:31:34 AM
Today's images and animation.
Title: Re: The 2020/2021 freezing season
Post by: Freegrass on September 21, 2020, 03:19:23 PM
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Title: Re: The 2020/2021 freezing season
Post by: Freegrass on September 21, 2020, 03:32:07 PM
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It's interesting how the deep cold is squeezed away throughout the basin. This will not bring back the melting season but could considerably slow down the freezing season.
Something I'll be keeping an eye on this winter is the northerlies passing through the Bering Strait. If those are above average again - like they were last season - than the Bering sea will see a large extent again.

Will this become a trend? Or was that just a fluke last season?
We'll know in spring...

One thing is for sure; We won't see the Laptev freezing over in the coming days...
Title: Re: The 2020/2021 freezing season
Post by: gandul on September 21, 2020, 03:45:51 PM
Yeah.
Also the cyclonic circulation on Greenland is pulling Atlantic storms up all the way to the Arctic. Not sure what to make of this but it looks warmer than predicted last week, where a cold polar vortex seemed to emerge.
Title: Re: The 2020/2021 freezing season
Post by: gandul on September 21, 2020, 03:50:03 PM
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I know it’s much to ask but could you generate the humidity one?? (please)
Title: Re: The 2020/2021 freezing season
Post by: Sublime_Rime on September 21, 2020, 06:52:59 PM
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Wow, is it just me, or does it seem like Fram export's about to go into overdrive? Perhaps all this sloshing around on the Atlantic front will slow refreeze over at least the next week?
Title: Re: The 2020/2021 freezing season
Post by: Paul on September 22, 2020, 02:13:25 AM
Wow.. Just how long is the Atlantic/Laptev refreeze going to take.. Large amounts of open water even by late November? Surely heading that way as there's been no cold air there whatsoever.

Yet the Beaufort has been cold and new ice has formed and we could see a fast refreeze here, the ice shape could be one of the strangest we have seen, at this rate the Bering Stright is more likely to freeze than the Laptev sea!
Title: Re: The 2020/2021 freezing season
Post by: Aluminium on September 22, 2020, 05:45:44 AM
September 17-21.

2019 (https://forum.arctic-sea-ice.net/index.php/topic,2888.msg230094.html#msg230094).
Title: Re: The 2020/2021 freezing season
Post by: Juan C. García on September 22, 2020, 05:59:03 AM
September 17-21.
Very interesting to see the "scorpion's tail" fade in Beaufort.
Title: Re: The 2020/2021 freezing season
Post by: Freegrass on September 22, 2020, 07:01:37 AM
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Here you go Gandul. If anyone else has a special request for freezing season, don't be shy to ask! The plan is to try and make one forecast a day now during freezing season, but I still have to figure out which one is the preferred forecast for the freezing season. I'm thinking temperature @ surface and @ 850 hPa for sure, and wind when a big event appears. But I'm not sure if precipitable water is useful in winter. It'll be cold and dry up there anyway... Just let me know! This DJ takes requests...  ::)
Title: Re: The 2020/2021 freezing season
Post by: nanning on September 22, 2020, 10:29:36 AM
According to climatereanalyzer, there's a 973 HPa low north of Novaya Zemlya.
Title: Re: The 2020/2021 freezing season
Post by: BornFromTheVoid on September 22, 2020, 11:57:26 AM
Today's images and animation
Title: Re: The 2020/2021 freezing season
Post by: be cause on September 22, 2020, 01:39:44 PM
 .. 'Today's images and animation' .. it looks like the 'meezing seazon' .. half melting , half freezing ..

 .. 'According to climatereanalyzer, there's a 973 HPa low north of Novaya Zemlya.' .. a little of hurricane Sally made it .. gfs's anticipation of this event was extremely good .. b.c.
Title: Re: The 2020/2021 freezing season
Post by: gerontocrat on September 22, 2020, 01:42:17 PM
According to climatereanalyzer, there's a 973 HPa low north of Novaya Zemlya.
You mean this one.....
Title: Re: The 2020/2021 freezing season
Post by: Darvince on September 22, 2020, 01:56:53 PM
Considering the current SST situation, I expect there to be an unusually long lasting polynya in the ice in the ESS until a record late date, perhaps mid-November or so.
Title: Re: The 2020/2021 freezing season
Post by: Milwen on September 22, 2020, 02:25:24 PM
A little unusual thing is happening. Hurricane Teddy is heading towards Canada and according to forecast it will reach Greenland as Tropical/Subtropical storm. It is too soon to tell if it will affect Arctic in some way but worth to mention it.

(https://www.nhc.noaa.gov/storm_graphics/AT20/refresh/AL202020_key_messages+png/115708_key_messages_sm.png)
Title: Re: The 2020/2021 freezing season
Post by: Phil. on September 22, 2020, 02:31:40 PM
.. 'Today's images and animation' .. it looks like the 'meezing seazon' .. half melting , half freezing ..

 .. 'According to climatereanalyzer, there's a 973 HPa low north of Novaya Zemlya.' .. a little of hurricane Sally made it .. gfs's anticipation of this event was extremely good .. b.c.
Current hurricane Teddy expected to hit S Greenland in a few days with tropical storm strength winds.
Title: Re: The 2020/2021 freezing season
Post by: Tor Bejnar on September 22, 2020, 03:11:08 PM
They actually aren't expecting a Greenlandic "Tropical/Subtropical storm" but are expecting a "powerful post-tropical cyclone" to approach Greenland's southern coast.

I find it curious the Hurricane Center shows projected storm strength through 5 days (typically) even when they expect the storm to lose 'tropical/subtropical' characteristics before the end of the forecast period.

Meanwhile, OT, Paulette, which hammered Bermuda a week ago, lost its tropical/subtropical characteristics when it dove into cooler waters, but, having turned south, regained them, so shows up on NOAA's Graphical Tropical Weather Outlook (https://www.nhc.noaa.gov/gtwo.php) chart as Paulette (again).  I remember years ago some major hurricane that struck the Gulf Coast, lost its tropical characteristics overland (so stopped showing up on NOAA's chart), went out to sea over the mid-Atlantic states, turned south over the Atlantic and, having regained tropical characteristics, headed west a second time and crossed the Florida Peninsula as a named depression.  (Fortunately, it never regained storm  forced winds, but it would have been 'one for the history books'.)
Title: Re: The 2020/2021 freezing season
Post by: colchonero on September 22, 2020, 03:30:35 PM
Wow.. Just how long is the Atlantic/Laptev refreeze going to take.. Large amounts of open water even by late November? Surely heading that way as there's been no cold air there whatsoever.

Yet the Beaufort has been cold and new ice has formed and we could see a fast refreeze here, the ice shape could be one of the strangest we have seen, at this rate the Bering Stright is more likely to freeze than the Laptev sea!

1. They are both very likely to freeze, for somebody that has never seen a freezing season before just to know. But I know what you meant. Which sea will freeze earlier.

2. There is almost no chance whatsoever, that Laptev won't freeze before there is any significant amount of ice in the Bering Sea, and Strait covered in ice. Laptev could be (very) late, depends on many  factors, (precondition, SST, LP/HP, wind, surface temperature  etc.) , but it certainly  won't be that late

The point is good, but to say it is more likely, is a bit of exaggeration.
Title: Re: The 2020/2021 freezing season
Post by: Freegrass on September 22, 2020, 03:58:24 PM
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Title: Re: The 2020/2021 freezing season
Post by: jdallen on September 22, 2020, 04:34:49 PM
Considering the current SST situation, I expect there to be an unusually long lasting polynya in the ice in the ESS until a record late date, perhaps mid-November or so.
Not so much polynya as just simply the seas not refreezing.

With so much insolation taken up this summer, combined with influxes of advected heat through intrusion of warmer southerly water on both sides of the Arctic, along with continued massive plumes of sensible and latent atmospheric heat (warm air, high moisture content), I'm expecting a refreeze along the lines of 2016/17, and a possible new low maximum.

Over the coming weeks, Siberia and eastern Europe will chill dramatically while the Arctic seas will remain quite warm.  There will be coastal freezing, but I expect the present heat and incoming storms through the fall will keep the ice at bay for a very long time, particularly in the Barents and Laptev.

On the Pacific side, I'm anticipating a late refreeze of the Chukchi, Okhotsk and Bering for much the same reasons, continuing and building on the trend we've seen the last few years in those regions.

I suspect the Beaufort, coastal Laptev and much of the ESS will freeze up fairly fast, again starting at existing ice edges or the coast, and leaving a warm gap between for some time.

The Kara I think is a wild card.  While it is shallow and close to the "cold continent", I think we're going to see a lot of flow into it from continuing tropical storms that will then sweep around counter-clockwise from it into the Arctic basin proper.  That may keep it open and the Atlantic side warmer for longer and generally reduce the desperately needed FDD's required for a strong refreeze and good volume production.

Not willing to speculate quantitatively on "Max" numbers yet even remotely, but both interested and concerned about what lies ahead.
Title: Re: The 2020/2021 freezing season
Post by: jdallen on September 22, 2020, 04:38:35 PM
A little unusual thing is happening. Hurricane Teddy is heading towards Canada and according to forecast it will reach Greenland as Tropical/Subtropical storm. It is too soon to tell if it will affect Arctic in some way but worth to mention it.

That's a HUGE tropical storm force wind field.  That's going to drag a huge plume of moisture and heat along with it all the way to the high Arctic.
Title: Re: The 2020/2021 freezing season
Post by: gerontocrat on September 22, 2020, 06:39:48 PM
A little unusual thing is happening. Hurricane Teddy is heading towards Canada and according to forecast it will reach Greenland as Tropical/Subtropical storm. It is too soon to tell if it will affect Arctic in some way but worth to mention it.

That's a HUGE tropical storm force wind field.  That's going to drag a huge plume of moisture and heat along with it all the way to the high Arctic.
GFS shows it being split into two as it hits the southern tip of Greenland on Friday - less energy heading into the Arctic ?
Title: Re: The 2020/2021 freezing season
Post by: gandul on September 23, 2020, 12:17:33 AM
Yeah.
Also the cyclonic circulation on Greenland is pulling Atlantic storms up all the way to the Arctic. Not sure what to make of this but it looks warmer than predicted last week, where a cold polar vortex seemed to emerge.
Judah Cohen predicts in fact this turn to anomalous warmth that can disrupt the formation of a not yet established polar vorteX
Title: Re: The 2020/2021 freezing season
Post by: icefisher on September 23, 2020, 01:35:06 AM
Tor, 1969 Hurricane Camille fits what you described above.
https://www.google.com/search?client=firefox-b-1-d&q=hurricane+camille+facts
Title: Re: The 2020/2021 freezing season
Post by: BornFromTheVoid on September 23, 2020, 10:13:07 AM
Today's images and animation. Beaufort Sea still hasn't figured out what it's doing.
Title: Re: The 2020/2021 freezing season
Post by: be cause on September 23, 2020, 10:26:14 AM
'Tor, 1969 Hurricane Camille fits what you described above.'

.. more likely H. Ivan in 2004 ..I remember it only too well .. I had been disappointed with the impact 1st time around on the Gulf coast so I idly doodled a looping track that brought it back for a second go , then watched in disbelief as it happened ... b.c. .

https://www.google.com/imgres?imgurl=https%3A%2F%2Fupload.wikimedia.org%2Fwikipedia%2Fcommons%2F3%2F32%2FIvan_2004_track.png&imgrefurl=https%3A%2F%2Fen.wikipedia.org%2Fwiki%2FMeteorological_history_of_Hurricane_Ivan&tbnid=P6Bdo1TZ0N3nBM&vet=12ahUKEwjvoKS7-v3rAhWa0uAKHY_WBw4QMygAegUIARDCAQ..i&docid=RE2Twa7wjeb1mM&w=2700&h=1669&q=hurricane%20ivan%20path&ved=2ahUKEwjvoKS7-v3rAhWa0uAKHY_WBw4QMygAegUIARDCAQ
Title: Re: The 2020/2021 freezing season
Post by: Paul on September 23, 2020, 12:59:02 PM
Wow.. Just how long is the Atlantic/Laptev refreeze going to take.. Large amounts of open water even by late November? Surely heading that way as there's been no cold air there whatsoever.

Yet the Beaufort has been cold and new ice has formed and we could see a fast refreeze here, the ice shape could be one of the strangest we have seen, at this rate the Bering Stright is more likely to freeze than the Laptev sea!

1. They are both very likely to freeze, for somebody that has never seen a freezing season before just to know. But I know what you meant. Which sea will freeze earlier.

2. There is almost no chance whatsoever, that Laptev won't freeze before there is any significant amount of ice in the Bering Sea, and Strait covered in ice. Laptev could be (very) late, depends on many  factors, (precondition, SST, LP/HP, wind, surface temperature  etc.) , but it certainly  won't be that late

The point is good, but to say it is more likely, is a bit of exaggeration.

Yes, it's an exageration i must point out, it's just the fact the Laptev once again is going to hace a slow refreeze like we saw in 2018 and 19 but this year could well be unprecedented how slow it could be. The Bering Stright has seen more cooler temperatures whilst the Laptev has barely had any cold so SSTS are way above normal. I think aslong weather patterns allow it, the Bering Stright might refreeze quicker this year but we shall see.
Title: Re: The 2020/2021 freezing season
Post by: Iain on September 23, 2020, 01:00:19 PM
Interested in late season movement of ice in the CAA.

My Hycom link shows up to date concentration and  thickness, but ice drift is from 2019

https://www7320.nrlssc.navy.mil/GLBhycomcice1-12/arctic.html

Is there a new site for drift, or is that product discontinued?
Title: Re: The 2020/2021 freezing season
Post by: Tom_Mazanec on September 23, 2020, 01:23:30 PM
I look forward to seeing if this freezing season peaks in the lowest maximum in history.
Title: Re: The 2020/2021 freezing season
Post by: Freegrass on September 23, 2020, 03:46:46 PM
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Title: Re: The 2020/2021 freezing season
Post by: BornFromTheVoid on September 23, 2020, 04:50:50 PM
10 days of refreezing (Sep 13th to 22nd). Nearly 6mb, click to play
Title: Re: The 2020/2021 freezing season
Post by: Paddy on September 23, 2020, 11:15:28 PM
I look forward to seeing if this freezing season peaks in the lowest maximum in history.

Surely it's much too early to say.
Title: Re: The 2020/2021 freezing season
Post by: Freegrass on September 24, 2020, 02:09:51 AM
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I forgot I already did temp today...  :-[
I'll do moisture tomorrow...

That storm is turning out to be the worst case scenario for the North Greenland ice, with winds over 60 km/h...  :'(

This is the last 24 and next 48 hours.
Title: Re: The 2020/2021 freezing season
Post by: Aluminium on September 24, 2020, 06:53:45 AM
September 19-23.

2019 (https://forum.arctic-sea-ice.net/index.php/topic,2888.msg230486.html#msg230486).
Title: Re: The 2020/2021 freezing season
Post by: OffTheGrid on September 24, 2020, 08:55:16 AM
Well. With Mosaic basically proving that the best piece of ice in the best position on the Atlantic side of the Lomonosov ridge LOST thickness on its entire transit from October to may, from 7m to 5m, through constant bottom melt, and never froze it's soggy core. And now that they can cruise at open water efficiency, from laptev to Fram north of 86 latitude, and never register any fresh freezable layer...
 There appears to be no such thing as a Arctic sea ice freezing season anymore in this half of the Arctic basin.
Therefore I suggest a poll to rename this forum the SiAlCa sea ice forum. Hopefully there will be a few years while those elements hydrated minerals can still stay cold enough to remain solid on those sectors polar seas. Unlike Venus.
Wry and somewhat twisted that this bad half joke may sound.

<To make such claims you need to point out the source. I am not aware of any such findings. O>
Title: Re: The 2020/2021 freezing season
Post by: BornFromTheVoid on September 24, 2020, 10:41:37 AM
Today's images and animation, with the transformation of the Beaufort tail into the Beaufort loop, once again.
(As always, a larger version of the animation on my twitter: https://twitter.com/Icy_Samuel/status/1309048320669691905)
Title: Re: The 2020/2021 freezing season
Post by: oren on September 24, 2020, 12:50:51 PM
From the looks of it, it appears the MYI in the Beaufort tail is still melting, moving around in southerly waters and with temps apparently not low enough. More of a graveyard than an ice preserve. This tail will not serve as the backbone of a resilient Beaufort next year.
Title: Re: The 2020/2021 freezing season
Post by: Freegrass on September 24, 2020, 02:48:17 PM
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Title: Re: The 2020/2021 freezing season
Post by: Niall Dollard on September 24, 2020, 10:22:36 PM
From the looks of it, it appears the MYI in the Beaufort tail is still melting, moving around in southerly waters and with temps apparently not low enough. More of a graveyard than an ice preserve. This tail will not serve as the backbone of a resilient Beaufort next year.

ESRL/PSL agrees. They suggest agressive bottom melting of 2cm per day through the forecast period. Further west around the dateline, there is a bit of bottom growth for a time, before more forecast southerlies put a stop to the growth.
Title: Re: The 2020/2021 freezing season
Post by: aslan on September 25, 2020, 09:26:00 AM
Well. With Mosaic basically proving that the best piece of ice in the best position on the Atlantic side of the Lomonosov ridge LOST thickness on its entire transit from October to may, from 7m to 5m, through constant bottom melt, and never froze it's soggy core. And now that they can cruise at open water efficiency, from laptev to Fram north of 86 latitude, and never register any fresh freezable layer...
 There appears to be no such thing as a Arctic sea ice freezing season anymore in this half of the Arctic basin.
Therefore I suggest a poll to rename this forum the SiAlCa sea ice forum. Hopefully there will be a few years while those elements hydrated minerals can still stay cold enough to remain solid on those sectors polar seas. Unlike Venus.
Wry and somewhat twisted that this bad half joke may sound.

On the Atlantic side, it is looking like that the halocline has taken a serious hit. And the weather is totaly nuts on the russian islands. As of the 24th, the record of the most crazy anomaly is probably for Ostrov Golomnjannyj. The current mean temperature, 4.7°C, is 4° (!) above the old record of 2012, and even 2°C above the warmest month ever recorded, August 1932. Every day have broken their daily record, 15 days had a Tx above the old monthly record, and even one Tn was above the monthly record of Tx... And all of this with 71 mm of rain (and I mean, really rain, liquid water at 5°C), wich is more than three time the normal monthly precipitation amount. From Ostrov Heiss to Ostrov Kotel'Nyj, crossing Khatanga and Ostrov Vize, mean monthly temperature are going to be 2 to 4°C above previous record, and going to be more than 3 sigma above normal. Seing such and anomaly over such an area (we are speaking of something like more than 2 millions of km² or 0.5% of Earth surface) for a monthly mean is unprecedent.
Title: Re: The 2020/2021 freezing season
Post by: BornFromTheVoid on September 25, 2020, 11:20:16 AM
Today's images and animation
Title: Re: The 2020/2021 freezing season
Post by: oren on September 25, 2020, 12:03:56 PM
Quote
the weather is totaly nuts on the russian islands
Thank you aslan for bringing these updates. The weather behavior in that region is almost a statistical impossibility. The pattern is stuck.
Title: Re: The 2020/2021 freezing season
Post by: paolo on September 25, 2020, 03:37:51 PM
Thanks Aslan for the weather data which explains well the presence of snow/firnpack saturated with water even in today's image (almost the end of September)

By the way, a post by Mauri Pelto on the Leningradskiy Ice Cap (Svernaya Zemlya Archipelago) was recently released:
https://blogs.agu.org/fromaglaciersperspective/2020/09/14/leningradskiy-ice-cap-snowcover-vanishes-in-2020-more-thinning-svernaya-zemlya/ (https://blogs.agu.org/fromaglaciersperspective/2020/09/14/leningradskiy-ice-cap-snowcover-vanishes-in-2020-more-thinning-svernaya-zemlya/)
Title: Re: The 2020/2021 freezing season
Post by: Freegrass on September 25, 2020, 04:58:07 PM
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Title: Re: The 2020/2021 freezing season
Post by: gerontocrat on September 25, 2020, 05:10:22 PM

And the weather is totaly nuts on the russian islands. As of the 24th, the record of the most crazy anomaly is probably for Ostrov Golomnjannyj. The current mean temperature, 4.7°C, is 4° (!) above the old record of 2012, and even 2°C above the warmest month ever recorded, August 1932. Every day have broken their daily record, 15 days had a Tx above the old monthly record, and even one Tn was above the monthly record of Tx... And all of this with 71 mm of rain (and I mean, really rain, liquid water at 5°C), wich is more than three time the normal monthly precipitation amount. From Ostrov Heiss to Ostrov Kotel'Nyj, crossing Khatanga and Ostrov Vize, mean monthly temperature are going to be 2 to 4°C above previous record, and going to be more than 3 sigma above normal. Seing such and anomaly over such an area (we are speaking of something like more than 2 millions of km² or 0.5% of Earth surface) for a monthly mean is unprecedent.
I attach the snow anomaly map from Noco Sun's website @ https://cryospherecomputing.tk/index.html
and from https://ccin.ca/ccw/snow/current - Snow Cover Extent, which shows almost no new snow in Eurasia this month. (What snow exists is mostly on The Tibetan Plateau / Himalaya)
Title: Re: The 2020/2021 freezing season
Post by: RoxTheGeologist on September 25, 2020, 08:47:22 PM

And the weather is totaly nuts on the russian islands. As of the 24th, the record of the most crazy anomaly is probably for Ostrov Golomnjannyj. The current mean temperature, 4.7°C, is 4° (!) above the old record of 2012, and even 2°C above the warmest month ever recorded, August 1932. Every day have broken their daily record, 15 days had a Tx above the old monthly record, and even one Tn was above the monthly record of Tx... And all of this with 71 mm of rain (and I mean, really rain, liquid water at 5°C), wich is more than three time the normal monthly precipitation amount. From Ostrov Heiss to Ostrov Kotel'Nyj, crossing Khatanga and Ostrov Vize, mean monthly temperature are going to be 2 to 4°C above previous record, and going to be more than 3 sigma above normal. Seing such and anomaly over such an area (we are speaking of something like more than 2 millions of km² or 0.5% of Earth surface) for a monthly mean is unprecedent.
I attach the snow anomaly map from Noco Sun's website @ https://cryospherecomputing.tk/index.html
and from https://ccin.ca/ccw/snow/current - Snow Cover Extent, which shows almost no new snow in Eurasia this month. (What snow exists is mostly on The Tibetan Plateau / Himalaya)

Snow is a good insulator - so not having any is a good thing as the weather cools. It allows more heat to emit into space. The fact that there is rain rather than snow and there's so much extra heat to lose - now that is very worrying.
Title: Re: The 2020/2021 freezing season
Post by: gandul on September 26, 2020, 12:55:29 AM
Not sure much heat is escaping with the disrupted weather right now and all the North Atlantic storms pouring in right now. We have a long freezing season ahead.

The EC predicts a super ridge sit over the pole at day 10. Not that it’s gonna happen, but it would not be still and quiet for the ice pack in any case.
Title: Re: The 2020/2021 freezing season
Post by: Aluminium on September 26, 2020, 07:00:00 AM
September 21-25.

2019 (https://forum.arctic-sea-ice.net/index.php/topic,2888.msg230826.html#msg230826).
Title: Re: The 2020/2021 freezing season
Post by: I’M IN LOVE WITH A RAGER on September 26, 2020, 07:02:01 AM
The Canadian and Siberian fronts look like 2 totally different animals progression-wise right now
Title: Re: The 2020/2021 freezing season
Post by: El Cid on September 26, 2020, 09:02:14 AM
September 21-25.

2019 (https://forum.arctic-sea-ice.net/index.php/topic,2888.msg230826.html#msg230826).

WOW

The Atlantic Front pushes beyond 85 N again. Amazing
Title: Re: The 2020/2021 freezing season
Post by: BornFromTheVoid on September 26, 2020, 12:42:13 PM
Todays images an animation
Title: Re: The 2020/2021 freezing season
Post by: BornFromTheVoid on September 26, 2020, 01:17:11 PM
September 21-25.

2019 (https://forum.arctic-sea-ice.net/index.php/topic,2888.msg230826.html#msg230826).

WOW

The Atlantic Front pushes beyond 85 N again. Amazing

Closest point is 503 km from the N. Pole
Title: Re: The 2020/2021 freezing season
Post by: gerontocrat on September 26, 2020, 03:24:56 PM
NSIDC Central Arctic Sea ice extent in 2020 is a record breaker for 40 days in a row, and not by a small amount.

What happens next? Eventually a very fast refreeze?
Title: Re: The 2020/2021 freezing season
Post by: Freegrass on September 26, 2020, 04:20:36 PM
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Title: Re: The 2020/2021 freezing season
Post by: NotaDenier on September 26, 2020, 04:22:42 PM
NSIDC Central Arctic Sea ice extent in 2020 is a record breaker for 40 days in a row, and not by a small amount.

What happens next? Eventually a very fast refreeze?

Prediction a fast refreeze as the Beaufort Donut fills in and then a slow refreeze due to warm seas and lack of ice for new ice to form on.
Title: Re: The 2020/2021 freezing season
Post by: BornFromTheVoid on September 26, 2020, 05:27:20 PM
Trend in the maximum extent minus the minimum extent.
Inset map of the 2020 max and min extent too.
Title: Re: The 2020/2021 freezing season
Post by: Glen Koehler on September 26, 2020, 07:19:23 PM
   One of your best graphics BTV, and that's saying something.
Title: Re: The 2020/2021 freezing season
Post by: Rodius on September 27, 2020, 04:09:12 AM
That graph shows that 2007 is a significant year yet again. The arctic hasn't gone back to pre 2007 since.
Title: Re: The 2020/2021 freezing season
Post by: Glen Koehler on September 27, 2020, 04:52:39 AM
  BTV - Could you do a version of the bar chart to show change from Sept Minimum to Minimum? 
That would visualize the stats posted by Oren showing what an absolute beast 2007 was.
Title: Re: The 2020/2021 freezing season
Post by: BornFromTheVoid on September 27, 2020, 11:59:28 AM
Todays images and animation


Title: Re: The 2020/2021 freezing season
Post by: BornFromTheVoid on September 27, 2020, 12:01:10 PM
  BTV - Could do a version of the bar chart to show change from Sept Minimum to Minimum? 
That would visualize the stats posted by Oren showing what an absolute beast 2007 was.

I think this is what you're after.
Title: Re: The 2020/2021 freezing season
Post by: Freegrass on September 27, 2020, 03:26:43 PM
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Title: Re: The 2020/2021 freezing season
Post by: Shared Humanity on September 27, 2020, 05:35:46 PM
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I watch your animations daily. one striking characteristic is the strong lows (cyclonic storms) that keep showong up in the ocean south of Alaska. is this normal?
Title: Re: The 2020/2021 freezing season
Post by: Freegrass on September 27, 2020, 08:28:23 PM
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I watch your animations daily. one striking characteristic is the strong lows (cyclonic storms) that keep showong up in the ocean south of Alaska. is this normal?
Someone will surely correct me if I'm wrong about this, but my guess is that the northern Pacific -  which is the largest continuous body of water in the Northern hemisphere - can be compared to the storms circulating around Antarctica. It's the Ferrel cell?

I'm surprised not more of these storms penetrate the arctic.
Title: Re: The 2020/2021 freezing season
Post by: Glen Koehler on September 27, 2020, 10:25:54 PM
  BTV - Could do a version of the bar chart to show change from Sept Minimum to Minimum? 
That would visualize the stats posted by Oren showing what an absolute beast 2007 was.
I think this is what you're after.
      Thanks BFTV, uber Nice!  That is even more informative than I expected.  I was looking to see a visual representation of the strong melt year from Sept 2006 to Sept 2007 - which the chart definitely demonstrates.  But it shows a lot more than that.  One bonus is seeing just how dynamic Arctic sea ice change is from year to year.

      The chart highlights some other major change years: 1990, 1993, and of course our favorite 2012.  On the other side of the coin, it shows 2013 as a large rebound year.

      Going out on a limb, I think the chart reflects the fact that 2007 was a "deep" melt year  ::) , whereas 2012 was kind of a superficial melt year in that much of the melt was due to the release of subsurface ocean heat by the GAC 2012 that caused late summer melt, but the loss of that heat also contributed to the large rebound in 2013. 

      Pushing my ignorance one more step, I think that the chart shows that 2019, while a 2nd place (at the time) finisher to 2012, was more a "deep" melt year, i.e. the real deal, not some flash in the pan caused by a temporary cyclone stirring up the waters. 

      And finally, I expect that 2020 was another "deep" melt year.  Yes the July cyclone in the Beaufort was a significant nudge, but it was not the driving factor behind the total melt, and did not release that heat bomb that lies at depth in the Beaufort Sea.  When that heat eventually is released, it will be an ice Armageddon -- for a while at least.  Such an event would likely be followed by a rebound year just like 2013 followed 2012.  Then again, with the ASI getting weaker from year to year, such a body blow could push it over the edge into a new equlibrium from which it cannot recover even with relatively mild melt weather in the subsequent year(s).
     
      If we look at each year as the first of a two-year pair to factor in the reboud effect, then 2007 really stands out as not only the biggest melt year, but a big melt year without a recovery the following year.  While 2019 was an intermediate melt year, it is one of only three (the others being 1997-1998, and 2007-2008) with two melt years in succession.  Both members of the 2019-2020 pair were stronger than the 1997-1998 pair.  (Worth noting that 97-98 was strong El Nino.  As was 2015-2016, which had back to back loss years, but much weaker.)

      I suspct that in addtion to the summer weather, the strong 2020 melt in the Laptev (and possibly ESS and Kara as well) this year may reflect the weakening of the thermocline due to Atlantification. If so, it is likely to be a persistent feature from now on, not a single year anomaly.

      And ominously, what drove the damage to the CAA-Greenland-North Pole triangle this year, including the north Greenland megacrack?  If it was purely a weather issue (which seems very possible) then it is less likely recur next year, though with continued warming such a weather scenario (or one with similar impact) also becomes increasing likely.  If the melting in the triangle was due to ocean forces, such as suspected for the Laptev, then it would be more likely to be a regular feature going forward.  I can't even guess at that question.  But the assault on the Atlantic-side ice edge during August and September 2020 has me suspecting that Atlantification contributed at least partically to the 2020 triangle melt.

      All just guesswork.  Interested in hearing what other folks think.  I just wish this very interesting intellecual exercise was about something other than the disruption of the planetary climate we all depend on.  I feel guilty enjoying watching the process unfold (and not the only one with those feelings I'm sure).  I tell myself it is important to stay informed.  Which is true.  But a part of me just likes watching math unfold regardless of the horrendous implications.

     I don't think the public really gets it that our entire civilization is built with reliance upon expectation of climatic norms for both levels and variaiblity around those norms, and upon dependable weather patterns like monsoons and other systems that drive agriculture and other endeavors.  I hope that ASIF, besides being fun to watch and enjoyable as my first and only on-line community, serves a purpose at raising awarenss.  When you vote, just remember: Creep Instability
Title: Re: The 2020/2021 freezing season
Post by: Pagophilus on September 28, 2020, 12:07:29 AM
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I watch your animations daily. one striking characteristic is the strong lows (cyclonic storms) that keep showong up in the ocean south of Alaska. is this normal?
Someone will surely correct me if I'm wrong about this, but my guess is that the northern Pacific -  which is the largest continuous body of water in the Northern hemisphere - can be compared to the storms circulating around Antarctica. It's the Ferrel cell?

I'm surprised not more of these storms penetrate the arctic.
I believe the polar vortices around each pole are stronger in winter.  Those vortices may help inhibit the intrusion of storms.  I leave it to the experts here to comment -- my understanding is just general and perhaps too simple.
Title: Re: The 2020/2021 freezing season
Post by: Pagophilus on September 28, 2020, 12:14:32 AM
  BTV - Could do a version of the bar chart to show change from Sept Minimum to Minimum? 
That would visualize the stats posted by Oren showing what an absolute beast 2007 was.
I think this is what you're after.
Thanks again BFTV.  Your legend grows.  Might we expect the future difference between successive minima to be, in general, smaller than in the past because much of the 'easy ice' is now being routinely melted out, leaving mostly just the stubborn 'CAB core' on the N.American side?  Or will the whole system maybe oscillate wildly as it approaches a 'BOE threshold'?
Title: Re: The 2020/2021 freezing season
Post by: oren on September 28, 2020, 02:42:18 AM
While 2019 was an intermediate melt year, it is one of only three (the others being 1997-1998, and 2007-2008) with two melt years in succession.
Looking again at BFTV's excellent chart, I wonder - wasn't 2011 lower than 2010? I always recall that 2012 was the culmination of 3 strong melting seasons in a row.
Title: Re: The 2020/2021 freezing season
Post by: Pagophilus on September 28, 2020, 03:47:51 AM
  BTV - Could do a version of the bar chart to show change from Sept Minimum to Minimum? 
That would visualize the stats posted by Oren showing what an absolute beast 2007 was.
I think this is what you're after.
...   On the other side of the coin, it shows 2013 as a large rebound year.

      Going out on a limb, I think the chart reflects the fact that 2007 was a "deep" melt year  ::) , whereas 2012 was kind of a superficial melt year in that much of the melt was due to the release of subsurface ocean heat by the GAC 2012 that caused late summer melt, but the loss of that heat also contributed to the large rebound in 2013.
 
...  I just wish this very interesting intellectual exercise was about something other than the disruption of the planetary climate we all depend on.  I feel guilty enjoying watching the process unfold (and not the only one with those feelings I'm sure).  I tell myself it is important to stay informed.  Which is true.  But a part of me just likes watching math unfold regardless of the horrendous implications. 

Glen, thanks for your post -- it helped me see the possible range of speculation, and your comment above on 2012 really opened my eyes to what might be happening. 

And the implications are ominous and terrible, but there is something in our nature that keeps us watching tragic plays, grim television series and disaster movies.  So, we are not alone in this type of fascination -- just human after all...

Title: Re: The 2020/2021 freezing season
Post by: Pagophilus on September 28, 2020, 04:21:58 AM
I hope that ASIF, besides being fun to watch and enjoyable as my first and only on-line community, serves a purpose at raising awareness. 

One last post, and I will stop, oren... 

Hey Glen,
I can assure you that, at least in my case, this site does a great deal to raise my awareness, understanding and concern about what is happening in the Arctic and globally.  And, because my work involves education, I then pass that knowledge and motivation on to many others, and I can do that with the authenticity that comes from what I gain here.  I suspect I am far from alone in this respect.  So, it may even be worth while putting up with me and all my posts!  ;)  This is my first and only on-line community as well.  My thanks to all who contribute so productively here.
Title: Re: The 2020/2021 freezing season
Post by: Aluminium on September 28, 2020, 07:09:48 AM
September 23-27.

2019 (https://forum.arctic-sea-ice.net/index.php/topic,2888.msg231114.html#msg231114).
Title: Re: The 2020/2021 freezing season
Post by: BornFromTheVoid on September 28, 2020, 10:34:47 AM
Today's images and animation.
Some big losses around the Chukchi region the last 2 days with southerlies dominating here. This looks likely to continue for the coming week, so definitely an area worth watching.
Title: Re: The 2020/2021 freezing season
Post by: Freegrass on September 28, 2020, 03:20:56 PM
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Wind + Temp @ 850hPa
Wind @ 250hPa
Large GiFS!
Title: Re: The 2020/2021 freezing season
Post by: Shared Humanity on September 28, 2020, 04:14:58 PM
BFTV - I know I have said this before but these three images and the one GIF are absolutely wonderful. Not sure what you could add that would provide anymore insight.

Don't know how long it takes you to put these together but thank you.

Combined with the temperature and wind animations provided by Freegrass makes this thread a delight to visit.

It would be really nice if these strong southerlies coming off of Siberia would go away.
Title: Re: The 2020/2021 freezing season
Post by: NeilT on September 28, 2020, 11:31:29 PM
Looking again at BFTV's excellent chart, I wonder - wasn't 2011 lower than 2010? I always recall that 2012 was the culmination of 3 strong melting seasons in a row.

10,11 and 12 were a strong melt years, much to some surprise as 10-11 and 11-12 were strong and moderate La Nina years respectively.  2012, early on, was not really considered anything special until it just kept on melting and then the storms took over at the end of the season and totally decimated the ice.

From Neven's update on July 20th, 2012, It shouldn't but it does (https://neven1.typepad.com/blog/2012/07/asi-2012-update-8-it-shouldnt-but-it-does.html).

Quote
I'm basically going to say the same thing as I did in the last ASI update: Weather patterns haven't been conducive to sea ice decrease, trend lines on graphs should be stalling, but they don't. As I've shown in yesterday's blog post comparing this year's weather patterns in June and July with previous record years, the decrease should have slowed down significantly like it did in 2010 and 2011, but it didn't. The 2012 SIE trend line shouldn't follow 2007 so closely, but it does. The 2012 SIA trend line shouldn't lead, but it does.

Then later on, Neven's Open thread on 9th Sept 2012 (https://neven1.typepad.com/blog/2012/09/minimum-open-thread.html),

Quote
Can we start speculating about the minimum yet? I know trend lines are still dropping, and after this crazy melting season, I don't feel able or willing to make any pronouncement on when it will stop. In 2010 and 2011 the weather forecast maps helped me to announce the minimum a few days in advance, but those maps aren't any help to me this year. All I'm seeing for the coming five days is a persistent high over the Siberian coast and a huge low developing near Iceland, reaching all the way to Scandinavia and the UK. Normally this would mean slowdown for ice decline or even minimum, but this melting season isn't normal.

It is easy to forget just how exceptional 2012 was.

2005,06 and 07 were also strong melting years.  2005 broke all sorts of records including massive media time due to new islands being reported "found" due to the melt back of the ice.

2006 was anomalous.  It was an incredibly warm year that suddenly went cool in August and killed any chance of a new record.  As can bee seen in the Arctic Sea Ice News Fall 2006 (http://nsidc.org/arcticseaicenews/2006/10/arctic-sea-ice-news-fall-2006/)

it is quite amusing to see 2005 recorded as a "record low".

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fnsidc.org%2Fsites%2Fnsidc.org%2Ffiles%2Fimages%2Fasina%2F20060912_timeseries.png&hash=1cd31907f9c7365e3179dff4b9171694)

This was also the year of the Unusual Polynya, if you are interested.

Right now I'm just sitting back and watching how the next few years play out.  Incredibly thin ice, incredibly low volume, increasingly higher CO2 concentrations in the atmosphere. Eventually something has to give and the only thing I can see is the impending BOE.  It is just a matter of when.
Title: Re: The 2020/2021 freezing season
Post by: oren on September 28, 2020, 11:34:00 PM
Thanks... Admittedly my question was simpler - was there an error in BFTV's min-to-min extent change chart?
Title: Re: The 2020/2021 freezing season
Post by: gandul on September 29, 2020, 12:03:05 AM
@NeilT thanks for bringing back those threads very early post 2012. Checking out 2013 Forum’s threads is another interesting exercise, to read the hyperbolic doom scenarios the usual apocalypse guys were writing at the time. Eight years of sobering melting seasons, including 2020, quite on the ‘boring’ downhill long-term trend, has quieted down the hyperbolic speeches considerably.

Title: Re: The 2020/2021 freezing season
Post by: BornFromTheVoid on September 29, 2020, 10:53:02 AM
Oren is correct, my chart was wrong. Need to check the rows the calculations are being performed on! The previous chart was the difference in the max to min from year to year, not the min to min.

Here's the actual minimum to minimum difference version (fingers crossed!)
Title: Re: The 2020/2021 freezing season
Post by: BornFromTheVoid on September 29, 2020, 10:56:55 AM
And the latest images and animation.
Title: Re: The 2020/2021 freezing season
Post by: SimonF92 on September 29, 2020, 12:51:53 PM
And the latest images and animation.

BFTV, the last frame in the final figure (the gif), shows the total change over the period- that is itself a nice visualisation and could be a stand-alone
Title: Re: The 2020/2021 freezing season
Post by: BornFromTheVoid on September 29, 2020, 01:42:21 PM
And the latest images and animation.

BFTV, the last frame in the final figure (the gif), shows the total change over the period- that is itself a nice visualisation and could be a stand-alone

Here ya go
Title: Re: The 2020/2021 freezing season
Post by: Freegrass on September 29, 2020, 01:42:49 PM
Latest Five Day Forecast
Wind + Temp @ Surface
Large GiF!
Title: Re: The 2020/2021 freezing season
Post by: Shared Humanity on September 29, 2020, 05:21:30 PM
Observations from Freegrass animation...

In 5 days, there are 3 strong lows that visit the ocean south of Alaska.

Fram export should run in reverse.

The migration/growth of ice on the Atlantic side will continue. I hope this will be freezing ice and not just an expansion of SIE and a reduction in compactness.

Southerlies off Siberia continue.

Title: Re: The 2020/2021 freezing season
Post by: SimonF92 on September 29, 2020, 05:58:45 PM
Thanks BFTV.

SH, if it is a reduction in compression/compaction then the leads between the floes will almost certainly be freezing over during the process at those projected temps
Title: Re: The 2020/2021 freezing season
Post by: Shared Humanity on September 29, 2020, 07:28:11 PM
Thanks BFTV.

SH, if it is a reduction in compression/compaction then the leads between the floes will almost certainly be freezing over during the process at those projected temps

Thank you. That was what I was asking.
Title: Re: The 2020/2021 freezing season
Post by: Pagophilus on September 30, 2020, 03:35:24 AM
For the last two years, as the first week in October arrived, ice extent growth showed a marked slackening for a week or two.  This also happened in 2016.  Very small sample, I know, but it could be interesting to see if this also happens this year.
Title: Re: The 2020/2021 freezing season
Post by: Aluminium on September 30, 2020, 06:41:29 AM
September 25-29.

2019 (https://forum.arctic-sea-ice.net/index.php/topic,2888.msg231114.html#msg231114).
Title: Re: The 2020/2021 freezing season
Post by: Freegrass on September 30, 2020, 07:49:00 AM
September 25-29.

2019 (https://forum.arctic-sea-ice.net/index.php/topic,2888.msg231114.html#msg231114).
The ice looks like a big balloon. Push it on one side, and the other side bulges out...
Title: Re: The 2020/2021 freezing season
Post by: BornFromTheVoid on September 30, 2020, 11:53:39 AM
Images and animation for today.
Title: Re: The 2020/2021 freezing season
Post by: Freegrass on September 30, 2020, 01:36:51 PM
Latest Five Day Forecast
Wind @ Surface
Wind + Temp @ 850hPa
Large GiFS!
Title: Re: The 2020/2021 freezing season
Post by: Shared Humanity on September 30, 2020, 10:43:24 PM
That GIF is clearly showing extensive melt occurring on the ice nearest the ESS.
Title: Re: The 2020/2021 freezing season
Post by: BornFromTheVoid on October 01, 2020, 11:34:14 AM
The slow changes continue, and the Chukchi bite keeps growing
Title: Re: The 2020/2021 freezing season
Post by: BornFromTheVoid on October 01, 2020, 12:37:46 PM
Here's the sea ice concentration animation for all of September. The dynamical movements are pretty interesting to watch.
There'll be a larger, better quality version going up on my twitter page in about 2.5 hours

(Large animation, ~11mb. Click to Play)
Title: Re: The 2020/2021 freezing season
Post by: SimonF92 on October 01, 2020, 12:39:58 PM
Here's the sea ice concentration animation for all of September. The dynamical movements are pretty interesting to watch.
There'll be a larger, better quality version going up on my twitter page in about 2.5 hours

(Large animation, ~11mb. Click to Play)

Really was touch-and-go for the Beaufort scorpion tail there, a few more days and it might have melted out
Title: Re: The 2020/2021 freezing season
Post by: oren on October 01, 2020, 01:48:45 PM
Indeed. Interestingly, the tail seems to be still melting a bit.


Thanks for the animations BFTV.
Title: Re: The 2020/2021 freezing season
Post by: BornFromTheVoid on October 01, 2020, 02:34:45 PM
Looks like most of the increase in the NSIDC extent is false ice towards the south east of Greenland, near Iceland.
Title: Re: The 2020/2021 freezing season
Post by: Freegrass on October 01, 2020, 03:21:45 PM
Latest Five Day Forecast
Wind + Temp @ Surface
Large GiF!

High pressure brings Low temperatures...
Title: Re: The 2020/2021 freezing season
Post by: Niall Dollard on October 01, 2020, 04:01:54 PM
Looking at the Jaxa extent graph trends on the data page posted by Gero, the slow start for 2020 is quite similar to the slow start for 2016. (albeit 2016 started from a slightly higher base).
Title: Re: The 2020/2021 freezing season
Post by: uniquorn on October 01, 2020, 04:36:51 PM
Up to sep29 this year, 2012 still defines the worst case scenario for Wipneus' CAB (https://sites.google.com/site/arcticseaicegraphs/regional)
Title: Re: The 2020/2021 freezing season
Post by: Shared Humanity on October 01, 2020, 09:56:47 PM
Much of the Chukchi, ESS and Laptev are still above freezing.
Title: Re: The 2020/2021 freezing season
Post by: Shared Humanity on October 01, 2020, 10:05:02 PM
Why does this orientation of the current state of Arctic Ice look so much scarier to me?
Title: Re: The 2020/2021 freezing season
Post by: Tor Bejnar on October 01, 2020, 10:21:52 PM
It makes me think all that ice is going to 'fall off' (break loose from Greenland/CAA/Alaska) and hit me on the head (as an icicle hanging from an eave might [or worse - refrozen half melted snow that partially slipped over the eave's edge before temporarily refreezing in place] ). 

With Greenland (or Canada) at the bottom, all that landmass will hold the ice up forever...
 :)
Title: Re: The 2020/2021 freezing season
Post by: Pagophilus on October 01, 2020, 10:31:46 PM
Much of the Chukchi, ESS and Laptev are still above freezing.
And more broadly, NOAA reports
"The Northern Hemisphere had its warmest summer on record at 1.17°C (2.11°F) above average, surpassing the now second-warmest such period set in 2016 and again in 2019."
https://www.ncdc.noaa.gov/sotc/global/202008
There must be a lot of heat stored in the N Hemisphere oceans generally from this record summer.
Title: Re: The 2020/2021 freezing season
Post by: Aluminium on October 02, 2020, 05:46:10 AM
September 27 - October 1.

2019 (https://forum.arctic-sea-ice.net/index.php/topic,2888.msg231981.html#msg231981).
Title: Re: The 2020/2021 freezing season
Post by: BornFromTheVoid on October 02, 2020, 12:57:06 PM
Todays update
Title: Re: The 2020/2021 freezing season
Post by: Freegrass on October 02, 2020, 01:34:39 PM
Latest Five Day Forecast
Wind @ Surface + Total Precipitable Water
Wind + Temp @ 850hPa
Large GiFS!
Title: Re: The 2020/2021 freezing season
Post by: Sepp on October 02, 2020, 02:20:08 PM
The first SMOS thin ice thickness map (https://seaice.uni-bremen.de/databrowser/#p=smos) of this freezing season is released.

Title: Re: The 2020/2021 freezing season
Post by: SimonF92 on October 02, 2020, 02:32:11 PM
The first SMOS thin ice thickness map (https://seaice.uni-bremen.de/databrowser/#p=smos) of this freezing season is released.

Thanks for the reminder about SMOS Sepp, last 11 years of Oct1st SMOS
Title: Re: The 2020/2021 freezing season
Post by: oren on October 02, 2020, 04:04:40 PM
Thanks for the SMOS post. As we suspected, all that MYI exported to the Beaufort tail has nearly melted out, and will give no resilience against next year's melting season.
Title: Re: The 2020/2021 freezing season
Post by: SimonF92 on October 02, 2020, 04:36:40 PM
Yeah there is barely any there, less than 20%
Title: Re: The 2020/2021 freezing season
Post by: gandul on October 02, 2020, 05:37:02 PM
Thanks for the SMOS post. As we suspected, all that MYI exported to the Beaufort tail has nearly melted out, and will give no resilience against next year's melting season.
It effectively amounts to open water except energy to refreeze further area is closer to zero.
For practical purposes Beaufort sea is free of MYI facing the refreeze season
Title: Re: The 2020/2021 freezing season
Post by: Glen Koehler on October 02, 2020, 06:58:04 PM
It makes me think all that ice is going to 'fall off' (break loose from Greenland/CAA/Alaska) and hit me on the head (as an icicle hanging from an eave might [or worse - refrozen half melted snow that partially slipped over the eave's edge before temporarily refreezing in place] ). 

With Greenland (or Canada) at the bottom, all that landmass will hold the ice up forever...
 :)
     To my eye that orientation highlights the fact that much of the remaining ice is at latitude below 80, so presumably more vulnerable to future melt.
Title: Re: The 2020/2021 freezing season
Post by: BornFromTheVoid on October 02, 2020, 07:18:06 PM
Playing around with some more data viz stuff.
So below is the September sea ice extent persistence. Basically, it's like stacking the average September sea ice extent for every year from 1979 to 2020 on top of each other.
Where sea ice is present in every year, the pixel value is 42 (white in the image).
Where it's present in 20 of the years, it gets a pixel values of 20 (light green)
Where it was only present in one year, it gets a value of 1 (dark orange)
And everything in between!

I'm open to suggestions on how best to display this data. I plan on doing the same for all other months too
Title: Re: The 2020/2021 freezing season
Post by: KenB on October 02, 2020, 08:13:12 PM
Playing around with some more data viz stuff.
So below is the September sea ice extent persistence. Basically, it's like stacking the average September sea ice extent for every year from 1979 to 2020 on top of each other.
Where sea ice is present in every year, the pixel value is 42 (white in the image).
Where it's present in 20 of the years, it gets a pixel values of 20 (light green)
Where it was only present in one year, it gets a value of 1 (dark orange)
And everything in between!

I'm open to suggestions on how best to display this data. I plan on doing the same for all other months too

Very nice.  For the low values, it might be nice to have a sense of what years contributed (confirming the presumption that for pixels with values 1,2,3 it's mostly very early years). 

I suppose you could keep the color scheme and use something like transparency?  Count each year as (y - 1978) and sum them up, then normalize for the number of years.  So a pixel with a count of 3 from 79,80,81 would be quite transparent but one from 06,14,18 would be less so?
Title: Re: The 2020/2021 freezing season
Post by: gerontocrat on October 02, 2020, 08:16:32 PM
Playing around with some more data viz stuff.
So below is the September sea ice extent persistence. Basically, it's like stacking the average September sea ice extent for every year from 1979 to 2020 on top of each other.
Where sea ice is present in every year, the pixel value is 42 (white in the image).
Where it's present in 20 of the years, it gets a pixel values of 20 (light green)
Where it was only present in one year, it gets a value of 1 (dark orange)
And everything in between!
I've done work and graphs on open water. i.e. the absence of ice. If one starts with the objective of showing that the ice is is disappearing, i.e progress towards an ice-free Arctic, then the data is essentially the same, but switched to the frequency of open water years, e.g.

where open water has always been there, pixel value = 42,
where open water has been there for only 10 years pixel value = 10.
where open water has never been there pixel value = 0.

The colour gradient would be the same - blue for open water, sliding through the rainbow to dark red and then finally to white.

A gif of the 12 months would show the waxing and waning of the ice. Another way is to take the 42 images for a particular month and gif that to show the ice retreating and the open water expanding.

Sounds like you are going to have fun.


Title: Re: The 2020/2021 freezing season
Post by: PragmaticAntithesis on October 02, 2020, 08:18:55 PM
I'm open to suggestions on how best to display this data. I plan on doing the same for all other months too

This pixel values for 35+ look very similar to the pixel values for open water, so you may want to flip the colour scale upside-down.
Title: Re: The 2020/2021 freezing season
Post by: gerontocrat on October 02, 2020, 08:31:28 PM
It makes me think all that ice is going to 'fall off' (break loose from Greenland/CAA/Alaska) and hit me on the head (as an icicle hanging from an eave might [or worse - refrozen half melted snow that partially slipped over the eave's edge before temporarily refreezing in place] ). 

With Greenland (or Canada) at the bottom, all that landmass will hold the ice up forever...
 :)
     To my eye that orientation highlights the fact that much of the remaining ice is at latitude below 80, so presumably more vulnerable to future melt.
And to my eye it tells me that the Russians know that the Arctic ocean belongs to them - might is right. Oh, and economic / military development will accelerate.
Title: Re: The 2020/2021 freezing season
Post by: BornFromTheVoid on October 02, 2020, 10:25:35 PM
Cheers for all the suggestions so far, lots of good stuff! I'll post a few more versions tomorrow for critiquing.

I am also working on a map that highlights the year that sea ice last covered a particular area.

Overall, I like the idea of generating a static image that kind of highlights directional and temporal melt momentum - like what parts of the Arctic are retreating towards the N. Pole the fastest, and how has this varied over time. Easy to do via animations, but a bit more tricky for static images.
Title: Re: The 2020/2021 freezing season
Post by: oren on October 03, 2020, 10:14:10 AM
BFTV, great visualization. May I make a few suggestions:
* As headline numbers have been "fake stable" since 2007, I suggest to do another version, of 2007-2020 only.
* As monthly averages often hide interesting details, I suggest to do it with daily data.
* As the end of September contains a lot of new thin ice, I suggest to do this with data for the 1st-10th of September only. This will give the probability of an ice cover close to the minimum in recent years.
* So the map would be made up of 14 years x 10 days each, and maximal rating would be 140.
* I still think the highest rank ("never had open water") should be white and all the rest a graded color scale.

* While I'm at it, it would be quite interesting to have the same visualization for other seasonal periods, for example 1-10th of August, of July, June. Each of these will answer a different question but in the same effective method. And it fits with A-Tean's discussion of early open water and its effects.

As a comparison, make another 1-10th Sep map for 1979-1992, before the ice began its serious decline. The two maps side by side will tell the story of the change that took place in the Arctic, and how some regions with perrenial ice cover became seasonally ice free, statistically speaking.

I realize what I wrote above is a load of work. Words are easy... but I appreciate any analysis you can provide along these lines. I have long dreamed of making these myself, but my graphic and netcdf skills are very poor unfortunately.
Title: Re: The 2020/2021 freezing season
Post by: BornFromTheVoid on October 03, 2020, 11:58:35 AM
Good suggestions Oren. I'll work on some of those during the coming week as I get the time.

Here's today images and animation. A flash filling in of the Chukchi bite, curious to see if it persists.
Title: Re: The 2020/2021 freezing season
Post by: Freegrass on October 03, 2020, 10:22:47 PM
Latest Five Day Forecast
Wind + Temp @ Surface
Large GiF!
Title: Re: The 2020/2021 freezing season
Post by: VeliAlbertKallio on October 04, 2020, 01:38:45 AM
There are also satellite sea ice maps now available for September 1-10 dates since 1964. Walt Meier can provide these 1960's to 1970's recovered from earlier satellite data with NASA.

BFTV, great visualization. May I make a few suggestions:
* As headline numbers have been "fake stable" since 2007, I suggest to do another version, of 2007-2020 only.
* As monthly averages often hide interesting details, I suggest to do it with daily data.
* As the end of September contains a lot of new thin ice, I suggest to do this with data for the 1st-10th of September only. This will give the probability of an ice cover close to the minimum in recent years.
* So the map would be made up of 14 years x 10 days each, and maximal rating would be 140.
* I still think the highest rank ("never had open water") should be white and all the rest a graded color scale.

* While I'm at it, it would be quite interesting to have the same visualization for other seasonal periods, for example 1-10th of August, of July, June. Each of these will answer a different question but in the same effective method. And it fits with A-Tean's discussion of early open water and its effects.

As a comparison, make another 1-10th Sep map for 1979-1992, before the ice began its serious decline. The two maps side by side will tell the story of the change that took place in the Arctic, and how some regions with perrenial ice cover became seasonally ice free, statistically speaking.

I realize what I wrote above is a load of work. Words are easy... but I appreciate any analysis you can provide along these lines. I have long dreamed of making these myself, but my graphic and netcdf skills are very poor unfortunately.
Title: Re: The 2020/2021 freezing season
Post by: BornFromTheVoid on October 04, 2020, 02:02:41 AM
Nice suggestions VAC. I'll try to get my hands on those maps.

Been up late dealing with reddit moderating drama, and playing about with some suggestions made previously.

As a start, here's the ice persistence map, and another highlighting the last year ice was present, for just the single day minima from 1979 to 1989.

I'll continue to adjust the colours, add more months/years/decades and try out other suggestions in the coming days too.
Title: Re: The 2020/2021 freezing season
Post by: Aluminium on October 04, 2020, 07:38:03 AM
September 29 - October 3.

2019 (https://forum.arctic-sea-ice.net/index.php/topic,2888.msg231981.html#msg231981).
Title: Re: The 2020/2021 freezing season
Post by: Niall Dollard on October 04, 2020, 10:20:54 AM
Freezing progress is so slow. In rugby parlance, these are the hard yards.

Not sure if it is thick enough to count yet but from Aluminum's video it looks like a good bit at the northern Beaufort is turning blue.
Title: Re: The 2020/2021 freezing season
Post by: BornFromTheVoid on October 04, 2020, 12:47:33 PM
Images and animation for today
Title: Re: The 2020/2021 freezing season
Post by: Freegrass on October 04, 2020, 03:23:15 PM
Latest Five Day Forecast
Wind + Temp @ 850hPa
Large Gif!
Title: Re: The 2020/2021 freezing season
Post by: Positive retroaction on October 04, 2020, 07:26:35 PM
Thank you, I follow this topic with enthusiasm
Would it be interesting to have the animation of the average extension of the last years (or a still image) to see the freezing speed of 2020 compared to other years? Maybe with an average day by day of extent progression?
Title: Re: The 2020/2021 freezing season
Post by: BornFromTheVoid on October 04, 2020, 10:32:52 PM
Here are the sea ice minimum extent persistence, based on the single day minimum values.
They are split, roughly, by decade.
Title: Re: The 2020/2021 freezing season
Post by: BornFromTheVoid on October 04, 2020, 10:35:23 PM
The same as above, but split based on the dates mentioned by Oren.
So we've 1979-1992, 1993-2006 and 2007-2020.
And a final one with all of the years.

I'll work on actually doing some actual analysis of these later in the week when I've some more time.

EDIT: Just spotted a mistake in the final image... just a sec Fixed! Though the images may be in the wrong order now. Oh well.
Title: Re: The 2020/2021 freezing season
Post by: Tor Bejnar on October 04, 2020, 11:11:45 PM
I thought you 'should' include 2020 in the last frame.  (You obviously read my mind ;))  After all, you included 1979 in the first one.  A GIF of the four frames might show the evolution very nicely.
Title: Re: The 2020/2021 freezing season
Post by: oren on October 04, 2020, 11:24:39 PM
Thank you so much BFTV, super-amazing. I will examine these images in more detail later, a lot to be found in there.
Title: Re: The 2020/2021 freezing season
Post by: grixm on October 05, 2020, 12:37:03 PM
Not sure if this is autocorrelated with the current low extent but the temperature anomaly forecast in the arctic and especially siberian seas is extreme, hovering around +15C.
Keep in mind the image below is the forecasted 10-day average. Usually you'd see quite low anomalies on such a map because such long term forecasts tend to go up and down and thus even out the average. But now the forecast just stays red hot in the ESS and Laptev for the entire 10-day period without pause.
Title: Re: The 2020/2021 freezing season
Post by: Paddy on October 05, 2020, 12:44:09 PM
Not sure if this is autocorrelated with the current low extent but the temperature anomaly forecast in the arctic and especially siberian seas is extreme, hovering around +15C.
Keep in mind the image below is the forecasted 10-day average. Usually you'd see quite low anomalies on such a map because such long term forecasts tend to go up and down and thus even out the average. But now the forecast just stays red hot in the ESS and Laptev for the entire 10-day period without pause.

Combined with how high the anomaly has been so far this freezing season (looking at dmi80N http://ocean.dmi.dk/arctic/meant80n.uk.php), you'd anticipate that ice will not be forming anything like as much as it should.
Title: Re: The 2020/2021 freezing season
Post by: Freegrass on October 05, 2020, 01:06:37 PM
Latest Five Day Forecast
Wind + Temp @ Surface
Large GiF!
Title: Re: The 2020/2021 freezing season
Post by: Pagophilus on October 05, 2020, 01:21:06 PM
Not sure if this is autocorrelated with the current low extent but the temperature anomaly forecast in the arctic and especially siberian seas is extreme, hovering around +15C.
Keep in mind the image below is the forecasted 10-day average. Usually you'd see quite low anomalies on such a map because such long term forecasts tend to go up and down and thus even out the average. But now the forecast just stays red hot in the ESS and Laptev for the entire 10-day period without pause.
A disturbing forecast (and while it is only a forecast, these forecasts are our only way of looking forward for the atmosphere).  Worth mentioning too is the lack of negative forecast anomalies for this period elsewhere in the Arctic, except in the CAA to some extent.  Given the heat stored in the Arctic seas around the main pack and the probable disturbances to and weakening of the halocline, what is there to argue against a slowing of the growth of ice extent (relative to most other years) over the next two weeks?  Such a slowing also happened in 2019, 2018 and 2016 around this time (although I have no idea why extent growth slowed in those three years).
Title: Re: The 2020/2021 freezing season
Post by: gandul on October 05, 2020, 01:27:47 PM
Not sure if this is autocorrelated with the current low extent but the temperature anomaly forecast in the arctic and especially siberian seas is extreme, hovering around +15C.
Keep in mind the image below is the forecasted 10-day average. Usually you'd see quite low anomalies on such a map because such long term forecasts tend to go up and down and thus even out the average. But now the forecast just stays red hot in the ESS and Laptev for the entire 10-day period without pause.
Laptev-ESS seas venting out their energy excess?

I would expect an acceleration of refreezing around the pack this week in view of Freegrass animations, but it is difficult to say.
Title: Re: The 2020/2021 freezing season
Post by: colchonero on October 05, 2020, 01:38:35 PM
Not sure if this is autocorrelated with the current low extent but the temperature anomaly forecast in the arctic and especially siberian seas is extreme, hovering around +15C.
Keep in mind the image below is the forecasted 10-day average. Usually you'd see quite low anomalies on such a map because such long term forecasts tend to go up and down and thus even out the average. But now the forecast just stays red hot in the ESS and Laptev for the entire 10-day period without pause.

Yup, and it will continue to be like that, as long as there is no ice formed. As long as there is open water, we won't see normal temperatyre at those locations, because surface temperature can't drop that much with open water instead of ice beneath, even if we would actually have "good" forecast(negative temp850hPa anomalies or neutral), with stable vortex and no heat from lower latitudes.  So those anomalies will remain intact for a while.
Title: Re: The 2020/2021 freezing season
Post by: SimonF92 on October 05, 2020, 01:48:12 PM
If the Arctic is the centre of climate change then Laptev/ ESS are rapidly becoming the centre of centre
Title: Re: The 2020/2021 freezing season
Post by: BornFromTheVoid on October 05, 2020, 01:52:13 PM
Today's images and animation
Title: Re: The 2020/2021 freezing season
Post by: RoxTheGeologist on October 05, 2020, 07:26:42 PM
Quote from: gandul link=topic=3299.msg288918#msg288918

....Laptev-ESS seas venting out their energy excess?


Right - that is my guess. No insulating ice to allow the temperature to drop.
Title: Re: The 2020/2021 freezing season
Post by: Stephan on October 05, 2020, 08:53:59 PM
Latest Five Day Forecast
Wind + Temp @ Surface
Large GiF!
A closer look onto ESS/Laptev on the one hand and the Barents on the other shows mostly southerly winds in both areas. This should slow down cooling at least a little bit, even if Siberia turned into "blue".
Title: Re: The 2020/2021 freezing season
Post by: Aluminium on October 06, 2020, 10:20:41 AM
October 1-5.

2019 (https://forum.arctic-sea-ice.net/index.php/topic,2888.msg232215.html#msg232215).
Title: Re: The 2020/2021 freezing season
Post by: aslan on October 06, 2020, 11:59:06 AM
Not sure if this is autocorrelated with the current low extent but the temperature anomaly forecast in the arctic and especially siberian seas is extreme, hovering around +15C.
Keep in mind the image below is the forecasted 10-day average. Usually you'd see quite low anomalies on such a map because such long term forecasts tend to go up and down and thus even out the average. But now the forecast just stays red hot in the ESS and Laptev for the entire 10-day period without pause.
Laptev-ESS seas venting out their energy excess?

I would expect an acceleration of refreezing around the pack this week in view of Freegrass animations, but it is difficult to say.

I doubt it. There is still a massive amount of oceanic heat and it is still looking like the halocline has taken a hit. And massive heat wave is still ongoing, no matter the temperature at 850 hPa. And this is not only a matter of absolute magnitude of the anomaly. October is probably going to be less extreme than September from a certain point of view. I mean, in term of deviation to the norm, the month of September was probably the most extreme month ever recorded anywhere on earth, no exaggeration. Ostrov Golomyanyj (data since the 30s...) has broken its monthly mean temperature by 3.3°C ! Ostrov Vize by 1.6°C after breaking the monthly record of august by 2.3. Same idea for Kotel'nyj, Izvestij Tsik, Dikson, Heiss (Polargmo), Hatanga etc... As an illustration, September mean temperature for Ostrov Kotel'nyj (WMO 21432). I have never heard of a heat wave so extreme over a two month period, and this is over an area of 2 millions of km² or something like that. Even though October will be extremely warm, such deviation is not likely in October (hopefully…). But in any case, there is really something ongoing on the Atlantic side. It will take more than a week of seasonal cooling for resorbing these anomalies.
Title: Re: The 2020/2021 freezing season
Post by: aslan on October 06, 2020, 12:41:40 PM
To illustrate, a set of graph for the period August - Septemeber. Record for Gmo Im. E. K. Federova, breaking its record by 2.2°C (cap Tcheliouskine),or 3.5 sigma above the most recent 30 years mean... And there is ~ 1500 km between Heiss (Polargmo or wmo 20046) and Hatanga (20891), which squared is ~ 2 millions km²
Title: Re: The 2020/2021 freezing season
Post by: binntho on October 06, 2020, 12:49:41 PM
aslan you're right these are truly amazing spikes. There is no denying that the Arctic is changing much faster than we expected.
Title: Re: The 2020/2021 freezing season
Post by: BornFromTheVoid on October 06, 2020, 02:32:34 PM
Images and animation for today.

Btw, I'm going to start making these updates roughly twice per week after this
Title: Re: The 2020/2021 freezing season
Post by: SimonF92 on October 06, 2020, 03:00:08 PM
Haven't run this script for a while
Title: Re: The 2020/2021 freezing season
Post by: SimonF92 on October 06, 2020, 04:17:49 PM
Updated code to provide continuous extent change as opposed to categorical
Title: Re: The 2020/2021 freezing season
Post by: aslan on October 06, 2020, 06:15:49 PM
aslan you're right these are truly amazing spikes. There is no denying that the Arctic is changing much faster than we expected.

It could also be noted that mean wind speed was a bit above average for this corner of Arctic in September. Excepted for Ostrov Heiss, which was near average with mean wind speed of 5.8 m/s, normal 6.0 m/s. For Ostrov Vize, 7 m/s versus 6.5 m/s, for Ostrov Golomyanyj it was 7.25 m/s for a normal of 5.7 m/s, for cape Chelyuskin 6.4 m/s versus 5.8 m/s, etc. It is not particulary noteworthy. But given the magnitude of the anomlies for latent and sensible heat, this is not helping at all. The amount of heat mixed during this month of Septemebr is crazy.
Title: Re: The 2020/2021 freezing season
Post by: uniquorn on October 07, 2020, 12:48:31 AM
There is still a massive amount of oceanic heat
Agreed.
amsr2, awi dev v103 overlaid onto mercator 0m ocean temperature, sep4-oct5
Title: Re: The 2020/2021 freezing season
Post by: Pagophilus on October 07, 2020, 04:41:35 AM
Oct 4 2020 sea ice extent compared with same date for 2012, 2016, 2019.
Interesting how late the W CAA was still open water in 2012 vs the other years.

http://nsidc.org/arcticseaicenews/sea-ice-comparison-tool/
Title: Re: The 2020/2021 freezing season
Post by: Freegrass on October 07, 2020, 08:16:33 AM
Latest Five Day Forecast
Wind @ Surface + Total Precipitable Water
Wind + Temp @ 850hPa
Wind @ 250hPa
Large GiFS!
Title: Re: The 2020/2021 freezing season
Post by: BornFromTheVoid on October 07, 2020, 03:02:15 PM
The current forecast is for quite a strong dipole to continue, with winds compressing the sea ice along the Chukchi and Russian facing edges, and spreading it out towards the Atlantic (animation below).
This shows up very nicely in the CMEMS sea ice forecasts to the 13th (2nd attachment) which predicts, amazingly, further significant losses along the Chukchi, ESS and (to a lesser extent) the Laptev ice edge. Gains in the other regions barely enough to produce growth overall.

I'd expect area and extent to be below 2012 next week, with truly exceptional regional record low ice values and further record smashing air temperatures as a result.
Title: Re: The 2020/2021 freezing season
Post by: wdmn on October 07, 2020, 03:10:50 PM

I'd expect area and extent to be below 2012 next week, with truly exceptional regional record low ice values and further record smashing air temperatures as a result.

NSIDC area crossed paths with 2012 and is now record low for the date according to Nico Sun's page.
Title: Re: The 2020/2021 freezing season
Post by: Shared Humanity on October 07, 2020, 03:27:22 PM
There is still a massive amount of oceanic heat
Agreed.
amsr2, awi dev v103 overlaid onto mercator 0m ocean temperature, sep4-oct5

What a fantastic gif. It shows how warm waters cause melt and prevent refreeze. Look at how the warm waters along the Alaskan coast continue to cause melt of the ice closest to Alaska. There is another example in Fram Strait. The Laptev is really going to struggle to freeze.
Title: Re: The 2020/2021 freezing season
Post by: BornFromTheVoid on October 07, 2020, 06:20:03 PM
Some great new forecast data made free by the ECMWF.
Includes sea ice, snow, waves, cloud and all the usual meteorological stuff.
A few sample below.
https://apps.ecmwf.int/webapps/opencharts/

Title: Re: The 2020/2021 freezing season
Post by: pearscot on October 07, 2020, 06:33:20 PM
Wow, this is kinda insane to see play out. I mean I can't say I'm in shock given how the melting season progressed, but there's just still sooo much open water. This year's freezing season will be one to watch.

I just can't help but wonder how all of this open water is mixing and affecting halocline, especially as the temperatures drop more. Anyways, thanks for the gifs/images thus far, they are appreciated.
Title: Re: The 2020/2021 freezing season
Post by: Aluminium on October 08, 2020, 07:27:19 AM
October 3-7.

2019 (https://forum.arctic-sea-ice.net/index.php/topic,2888.msg232440.html#msg232440).
Title: Re: The 2020/2021 freezing season
Post by: Freegrass on October 08, 2020, 09:29:18 AM
Latest Five Day Forecast
Wind + Temp @ Surface
Large GiF!
Title: Re: The 2020/2021 freezing season
Post by: jens on October 08, 2020, 10:16:30 AM
2019 had a slow refreeze until late October. 2020 is following the same path at least till mid-October. I'd wager a guess that "slow refreeze" is the new normal.
Title: Re: The 2020/2021 freezing season
Post by: sailor on October 08, 2020, 12:12:34 PM
2019 had a slow refreeze until late October. 2020 is following the same path at least till mid-October. I'd wager a guess that "slow refreeze" is the new normal.

This is "good", in the sense that, although the Arctic seas contain more energy that the yesteryears, it is a recognized negative feedback that same Arctic seas are so wide open that refreeze is hard to come, and a lot of this energy excess is lost in the process. Otherwise Arctic sea ice would be collapsing much faster.
Title: Re: The 2020/2021 freezing season
Post by: binntho on October 08, 2020, 12:20:59 PM
It's an interesting point: Is ever-slower refreeze a big negative feedback on planetary warming in general and Arctic warming in particular? Is it enough to cause a noticeable slowdown in warming? How does it compare quantitatively with the positive feedback of less albedo during months of insolation?

Or in other word: Will the positive feedback of less ice during insolation be neutered and even overcome by the negative feedback of large areas of open ocean once the sun goes down? Perhaps the latter is not so big as it could be since it also causes increased cloudiness and H2O in the atmosphere, thus replacing one blanket with another?
Title: Re: The 2020/2021 freezing season
Post by: Freegrass on October 08, 2020, 12:51:12 PM
It's an interesting point: Is ever-slower refreeze a big negative feedback on planetary warming in general and Arctic warming in particular? Is it enough to cause a noticeable slowdown in warming? How does it compare quantitatively with the positive feedback of less albedo during months of insolation?

Or in other word: Will the positive feedback of less ice during insolation be neutered and even overcome by the negative feedback of large areas of open ocean once the sun goes down? Perhaps the latter is not so big as it could be since it also causes increased cloudiness and H2O in the atmosphere, thus replacing one blanket with another?
If the arctic ocean contain enough heat to melt the ice twice over, wouldn't all that stirring up of the open ocean cause all that heat to come up to the surface through mixing, and wouldn't that be of concern for the halocline?
Title: Re: The 2020/2021 freezing season
Post by: cognitivebias2 on October 08, 2020, 01:18:19 PM
It's an interesting point: Is ever-slower refreeze a big negative feedback on planetary warming in general and Arctic warming in particular? Is it enough to cause a noticeable slowdown in warming? How does it compare quantitatively with the positive feedback of less albedo during months of insolation?

Or in other word: Will the positive feedback of less ice during insolation be neutered and even overcome by the negative feedback of large areas of open ocean once the sun goes down? Perhaps the latter is not so big as it could be since it also causes increased cloudiness and H2O in the atmosphere, thus replacing one blanket with another?

Interesting paper, with open access, discusses both energy balance and the halocline:
Cooling down the world oceans and the earth by enhancing the North Atlantic Ocean current
https://link.springer.com/article/10.1007/s42452-019-1755-y

"Recent climate models have shown that the increase in solar radiation absorption with the melted Arctic water is slightly higher than the increased longwave irradiation into space, as shown in Fig. 2b [16]. In other words, heat balance in the Arctic region is reached with or without the ice cover, warming up the atmosphere, cooling down the ocean and maintaining the overall heat balance of the Arctic region at equilibrium.

A study by [17] has calculated the net heat flux of the Arctic region (Fig. 2c). In locations covered by ice, the net heat flux loss is around 8 W/m2 smaller when compared to areas not covered by ice."


The article cited above as [17] from 2007 has a few famous names attached:

The large‐scale energy budget of the Arctic
Mark C. Serreze  Andrew P. Barrett  Andrew G. Slater  Michael Steele  Jinlun Zhang  Kevin E. Trenberth

https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2006JD008230

Title: Re: The 2020/2021 freezing season
Post by: Shared Humanity on October 08, 2020, 02:18:10 PM
Pretty clear from Freegrass's animation that the Arctic is struggling to establish cold temperatures over the Siberian side of the ocean. Combine this with continuous lows in the Laptev pulling air off of Siberia and stiring the open ocean...well, I think the very slow refreeze will continue here.
Title: Re: The 2020/2021 freezing season
Post by: aslan on October 08, 2020, 02:25:37 PM
This article pretty much ignore clouds or overall atmospheric circulation, or anything else, and is just saying that if you remove sea ice, a lot, lot, lot of energy will be radiated to space in winter. Yes of course, nothing new. But it is likely that things will not proceed as linearly. Studies and measures are showing that it seems likely that open water during fall and winter is going to destabilize the PBL. Implying more clouds and moisture, which is going to limit the amount of heat lost to space. And atmospheric circulation, and oceanic circulation, and etc... are also going to respond to an ice free Arctic and establish a new equilibrium which is definitively not going to be the same that "all else equal excepted for sea ice".
Title: Re: The 2020/2021 freezing season
Post by: binntho on October 08, 2020, 02:35:19 PM
The first paper linked by cognitivebias2 above states:

Quote
This paper argues that if the North Atlantic Ocean current could maintain the Arctic Ocean ice-free during the winter, the longwave radiation heat loss into space would be larger than the increase in heat absorption due to the albedo effect.

Which implies that the negative feedback from outgoing winter radiation is ultimately bigger than the positive feedback of increased albedo in summer. But as aslan points out, increased cloud cover could very easily change this calculation.

And I seem to remember that during the last interglacial, when we know that the Arctic was at leas seasonally ice-free, Arctic Amplification was significant which implies that the positive feedback of increased albedo trumped the negative of increased outgoing radiation.
Title: Re: The 2020/2021 freezing season
Post by: aslan on October 08, 2020, 02:41:55 PM
Yes, Arctic was ice free many times in the geological time. It is true that loosing ice cover in winter would in theory implies a massive heat loss by longwave radiation to space, but things are not as simple as "If I pull out your blanket, you are going to freeze to death.". And there is over factors at play. This discussion will lead us off topic if we continue, but an ice free Arctic means also a complete reorganization of the atmospheric and oceanic circulation.
Title: Re: The 2020/2021 freezing season
Post by: gandul on October 08, 2020, 03:21:36 PM
It's an interesting point: Is ever-slower refreeze a big negative feedback on planetary warming in general and Arctic warming in particular? Is it enough to cause a noticeable slowdown in warming? How does it compare quantitatively with the positive feedback of less albedo during months of insolation?

Or in other word: Will the positive feedback of less ice during insolation be neutered and even overcome by the negative feedback of large areas of open ocean once the sun goes down? Perhaps the latter is not so big as it could be since it also causes increased cloudiness and H2O in the atmosphere, thus replacing one blanket with another?
If the arctic ocean contain enough heat to melt the ice twice over, wouldn't all that stirring up of the open ocean cause all that heat to come up to the surface through mixing, and wouldn't that be of concern for the halocline?

Your scenario has however two problems:
1. The Arctic has had enough heat to be melted out several times since basically forever. (At least since the last glaciation). It is not a new thing.
2. If storms in Fall pull out ocean heat in enormous quantities as you suggest, this heat will be lost in a very large sink: winter night. The result would be that the Arctic as a system loses heat.

Do the math. The heat to keep the ocean open in winter is huge. Several times the heat input during the melting season. I have done the math before.
Title: Re: The 2020/2021 freezing season
Post by: The Walrus on October 08, 2020, 03:25:26 PM
This article pretty much ignore clouds or overall atmospheric circulation, or anything else, and is just saying that if you remove sea ice, a lot, lot, lot of energy will be radiated to space in winter. Yes of course, nothing new. But it is likely that things will not proceed as linearly. Studies and measures are showing that it seems likely that open water during fall and winter is going to destabilize the PBL. Implying more clouds and moisture, which is going to limit the amount of heat lost to space. And atmospheric circulation, and oceanic circulation, and etc... are also going to respond to an ice free Arctic and establish a new equilibrium which is definitively not going to be the same that "all else equal excepted for sea ice".

True, however the same could be said for cloud cover in summer.  Blocking the major source of incoming heat would have an effect on summer ice melt also.
Title: Re: The 2020/2021 freezing season
Post by: SimonF92 on October 08, 2020, 04:04:52 PM
Would really like to see that math, from a curiosity point of view
Title: Re: The 2020/2021 freezing season
Post by: nukefix on October 08, 2020, 04:16:22 PM
Some great new forecast data made free by the ECMWF.
Indeed!

https://www.ecmwf.int/en/forecasts/charts

Title: Re: The 2020/2021 freezing season
Post by: BornFromTheVoid on October 08, 2020, 08:16:36 PM
CMEMS sea ice forecast shows almost no growth over the next week. Should it come off, record lows, and by huge margins, should be expected soon.

Below is a comparison between 2012 and 2020, with AMSR2 data to the 7th for 2020, and CMEMS for 8th to 14th.
Title: Re: The 2020/2021 freezing season
Post by: wdmn on October 08, 2020, 11:44:36 PM
CMEMS sea ice forecast shows almost no growth over the next week. Should it come off, record lows, and by huge margins, should be expected soon.

Below is a comparison between 2012 and 2020, with AMSR2 data to the 7th for 2020, and CMEMS for 8th to 14th.

Wish I had the skill (or at least the application) to overlay this on bathymetry. A lot that new ice in 2012 was in the shallower Siberian seas growing from the ice edge. Ice edge this year looks to be mostly over deeper waters still.
Title: Re: The 2020/2021 freezing season
Post by: gandul on October 09, 2020, 12:14:25 AM
Would really like to see that math, from a curiosity point of view
It involves Boltzmann equation for typical winter temperatures, and assumption of mostly clear skies.

As Bintho points out, this is a bad approximation (clouds) but gives you an order of magnitude, trust me, the resulting kw/m2 are overwhelming. Any believable heat pulled out now by storms over open ocean will be radiated out to space during the 6-month winter night.

So the longer the ocean remains open and agitated, the more energy is released now and evacuated from planet Earth.
Title: Re: The 2020/2021 freezing season
Post by: gandul on October 09, 2020, 12:29:24 AM
The forecasts keep predicting a disruptive polar ridge (an Autumn GAAC) rather than a solid PV. Guess the more energy out to space, the colder 2021 melting season will be?

Sounds like rejoicing news (I know how much you guys care and root for the polar bears).
Title: Re: The 2020/2021 freezing season
Post by: I’M IN LOVE WITH A RAGER on October 09, 2020, 12:54:24 AM
gandul I'm confused as to how energy leaving now (from upper layers of the water) would affect the next melting season, when the water is not even cold enough to freeze yet. Isn't what is being observed the result of an energy surplus "venting" towards baseline, not a baseline amount of energy venting towards "even colder"? (If we are actually assuming this effect is as significant as some are stating)
Additionally, isn't most of the energy in the basin stored in the depths, which is not leaving in large enough quantities to decline on a year to year basis? I feel like the effects of this hypothesized development are being a little overstated since this transition from polar day to polar night happens every year and yet the net energy in the basin continues to grow. Even last year's decent recovery did not stop the weather from shaking things up this summer, so I feel like it is very bold to make such a direct connection when there are many factors at play in a quite chaotic system
If I am misunderstanding though, I'd appreciate if someone could clarify what I am missing
Title: Re: The 2020/2021 freezing season
Post by: A-Team on October 09, 2020, 01:16:19 AM
Quote
Would really like to see that math
It won't be forthcoming because in addition to imperative cloud considerations, it would also have to explain why the Barents no longer freezes over in winter despite reaching 80ºN where it's also rather cold. Ice may blow in from the Kara or across the FJL-SV line but apparently no longer forms significant sea ice on its own.

Like the Yermak, Barents too receives a branch of Atlantic Water inflows and has largely lost its stratification (previously maintained by fresh water from ice melt); in terms of wind mixing, over a third of the Arctic Ocean (mostly on the Siberian side) has shallower water than the ~300m deep Barents.

The Bering Sea too no longer freezes over in winter despite large water exchanges with the Chukchi -- which still has open water on Jan 1st in recent years. The Chukchi is well over a thousand km south of the Barents and only partly above the Arctic Circle.

There are no instances over the last 7 years of Jan 1st open water in the ESS or Laptev. This year bears watching however for open water persisting after mid-November because of the cumulative impact of double diffusion of Atlantic Waters over the years and the massive solar heat input this July to early low albedo open waters of the Laptev.

The AW brings in enough heat each year to melt all the ice, the question has always been how much of that heat it leaves behind -- more and more per Mercator Ocean and Laptev moorings (Polyakov 2019).

It should not be assumed that all the open water in the Arctic Basin will magically refreeze in winter. As time goes on, more and more open water will persist later and later into the depths of winter. A lot of blackbody radiation (Planck effect) comes right back down so it doesn't have the cooling effect that one might imagine.

It's all about clouds and moisture intrusions from mid-latitude:

Following moist intrusions into the Arctic using SHEBA observations in a Lagrangian perspective
S. Mubashshir Ali  Felix Pithan  19 June 2020
https://rmets.onlinelibrary.wiley.com/doi/full/10.1002/qj.3859

"Warm and moist air masses are transported into the Arctic from lower latitudes throughout the year. Especially in winter, such moist intrusions (MIs) can trigger cloud formation and surface warming. While a typical cloudy state of the Arctic winter boundary layer has been linked to the advection of moist air masses, direct observations of the transformation from moist midlatitude to dry Arctic air are lacking.

"The Surface Heat Budget of the Arctic (SHEBA) and the Norwegian Young Sea Ice (N‐ICE2015) expeditions have shown that the wintertime Arctic boundary layer is characterized by a bi‐modal distribution between a radiatively clear and an opaquely cloudy state. This bi‐modality is also observed in the time series from the ARM site at Utqiaġvik for the boreal winter (F Pithan 2014, fig 10). The two states have different net surface long‐wave radiation (NetLW) as the clear state is characterised by strong long‐wave cooling (NetLW ∼ − 40 W·m−2) under clear skies or ice clouds and the cloudy state with little to no surface cooling (NetLW ∼ 0 W·m−2) under low‐level mixed‐phase clouds."

Cloud Radiative Forcing of the Arctic Surface: The Influence of Cloud Properties, Surface Albedo, and Solar Zenith Angle
Matthew D. Shupe; Janet M. Intrieri
J. Climate (2004) 17 (3): 616–628.  classic paper on subject from co-leader of Mosaic
https://journals.ametsoc.org/jcli/article/17/3/616/30440/Cloud-Radiative-Forcing-of-the-Arctic-Surface-The

"An annual cycle of cloud and radiation measurements made as part of the Surface Heat Budget of the Arctic (SHEBA) program are utilized to determine which properties of Arctic clouds control the surface radiation balance. Surface cloud radiative forcing (CF), defined as the difference between the all-sky and clear-sky net surface radiative fluxes, was calculated from ground-based measurements of broadband fluxes and results from a clear-sky model. Longwave cloud forcing (CFLW) is shown to be a function of cloud temperature, height, and emissivity (i.e., microphysics). Shortwave cloud forcing (CFSW) is a function of cloud transmittance, surface albedo, and the solar zenith angle. The annual cycle of Arctic CF reveals cloud-induced surface warming through most of the year and a short period of surface cooling in the middle of summer, when cloud shading effects overwhelm cloud greenhouse effects."

Arctic amplification is caused by sea-ice loss under increasing CO2
Aiguo Dai, Dehai Luo, Mirong Song & Jiping Liu   10 January 2019
https://www.nature.com/articles/s41467-018-07954-9

"Increased outgoing longwave radiation and heat fluxes from the newly opened waters cause Arctic Amplification, whereas all other processes can only indirectly contribute to it by melting sea-ice. Seasonal sea-ice melting from May to September opens a large portion of the Arctic Ocean, allowing it to absorb sunlight during the warm season. Most of this energy is released to the atmosphere through longwave (LW) radiation, and latent and sensible heat fluxes during the cold season from October to April when the Arctic Ocean becomes a heat source to the atmosphere10 (Supplementary Figure 1)"
Title: Re: The 2020/2021 freezing season
Post by: Wildcatter on October 09, 2020, 05:17:48 AM
Am I thinking of this correctly?

"Heat loss" is a big factor, along with clouds and water vapor, in the more extreme autumn/fall and winter arctic amplification? Along with clouds, water vapor, etc. Ie, greater "heat loss" will generally lead to warmer air temperatures?  Because heat isn't just teleported right into space

If so, state transitions are probably underrated. For example, GFS forecasting about a +4C temp anomaly in the Arctic through the third week of October, and that's relative to 1979-2000. Not sure what last year was, but probably fairly high given how it played out. Stands to reason, those kinds of anomalous temps inevitably lead to environment changes if they become the new "normal", and as environment transitions to a new, warmer state, logical to assume that state is less conducive to "heat loss", except there will be even greater heat up-take + various factors and likely even higher "heat loss". Which just exacerbates the situation into greater temp anomalies, greater changes. And so it goes.

Pretty nasty feedback loop, if that's more or less, a reasonable assertion. Not a great signal 2020 wasn't a "rebound" year, and seeing slow re-growth similar to year prior. Will need to see how it plays out, and probably next year for better confirmation, but could be evidence we're starting to enter a new-er transitional state.
Title: Re: The 2020/2021 freezing season
Post by: I’M IN LOVE WITH A RAGER on October 09, 2020, 05:28:49 AM
IMO A-Team's in depth write-up and Wildcatter's hypothesis seem to reconcile better with what we are currently observing as well as the trend in seas such as the Barents than the other theories that have been presented in this thread recently regarding radiating heat loss, but I guess ultimately time will tell. I would assume that if we reach mid-late November and the basin (especially the Siberian side) is still extremely anomalously low, that we will not be seeing any sort of above average ice cover in the ESS, Kara or Laptev seas by the end of spring 2021.

Personally, I think the massive energy influx into the Siberian Arctic this summer may have begun the push over the edge for those seas, which may be trending faster towards a Barents-like state than before, opening up potential for more rapid Atlantification, but I do not want to wholeheartedly commit to this hypothesis with only a data point or two. The next few summers should provide a clearer trend picture, at which point a more definitive call can be made regarding the rate of change of that region.
Title: Re: The 2020/2021 freezing season
Post by: I’M IN LOVE WITH A RAGER on October 09, 2020, 05:40:16 AM
I think it is also worth noting that the last 2 weeks of October and the first few days of November were the stretch that significantly differentiated 2019's refreeze from 2016's refreeze, so we are likely rapidly approaching a critical period of development and therefore important observation, since the next month or so may heavy-handedly shape the progression of the ice growth this winter.
Title: Re: The 2020/2021 freezing season
Post by: binntho on October 09, 2020, 06:01:45 AM
Truly fantastic input by A-Team which has in effect turned my understanding of Arctic amplification upside down - expanding open water is the driving mechanism, but higher albedo is not the primary cause of Arctic Amplification as I have always assumed, and neither can winter heat escape be deemed a negative feedback.

Rather it is the winter heat escape from open water, combined with increased water vapor and cloudiness, that is the primary cause of Arctic amplification. The negative feedback has been turned into a positive one, and a nasty one at that, according to Wildcatter.

Following from this, one is tempted to draw the conclusion that a late refreeze will increase the likelihood of a warmer winter and thinner ice. Nasty indeed.
Title: Re: The 2020/2021 freezing season
Post by: I’M IN LOVE WITH A RAGER on October 09, 2020, 06:46:05 AM
On another note, the transformation of the Beaufort tail over the last 2-3 weeks has been pretty dramatic when directly compared. I was pretty surprised myself when I looked at the two images side-by-side. September 17 vs October 8 AMSR2 product.
Title: Re: The 2020/2021 freezing season
Post by: oren on October 09, 2020, 06:51:41 AM
The issue is quite simple. Heat escape is driven by more heat in the system. The more heat, the longer it remains, the longer open water refuses to freeze. Sure, the heat is eventually lost to space during the long winter. Sure, the more heat is there the more heat is lost. But this process by itself cannot protect the Arctic and its sea ice. It cannot be called a proper negative feedback. The Arctic is trying to heal its summer wounds, is all.
Eventually a time will come when the freezing season ends while some open water has still not frozen. Currently this doesn't happen within the Arctic Basin, with maybe some localized exceptions. However, a late freeze is disastrous in itself, as the resulting ice is thinner and more prone to melt next season.
Title: Re: The 2020/2021 freezing season
Post by: oren on October 09, 2020, 06:59:47 AM
On another note, the transformation of the Beaufort tail over the last 2-3 weeks has been pretty dramatic when directly compared. I was pretty surprised myself when I looked at the two images side-by-side. September 17 vs October 8 ASMR2 product.
Thanks for the comparison. Indeed, all that thick MYI diligently exported from the CAB has mostly melted out or thinned considerably, with bottom melt enhanced by the vigorous movements to and fro. The deep freezing temps have never reached this far south in the Beaufort yet, though they've been around more central parts of the basin for nearly a month. Finally the forecast now calls for cooling of the "tail" region in the next few days, but too little too late IMHO.
Title: Re: The 2020/2021 freezing season
Post by: jdallen on October 09, 2020, 08:04:22 AM
It's an interesting point: Is ever-slower refreeze a big negative feedback on planetary warming in general and Arctic warming in particular? <snip>

I'd say no.  The slow refreeze is happening exactly because there is so much heat in the system, outgoing radiation can't cool things off fast to drop it to where the sea surface freezes.

Secondary effects from this are going to be general disruption of northern hemisphere atmospheric circulation, with massive break outs of cold air from the polar regions, and massive inflows of heat and moisture out of the similarly but not as severely overheated tropics.  The Enthalpy bucket is overflowed faster and more voluminously than the drain can carry away the extra.
Title: Re: The 2020/2021 freezing season
Post by: binntho on October 09, 2020, 08:21:46 AM
It cannot be called a proper negative feedback. The Arctic is trying to heal its summer wounds, is all.

Increased outgoing long-wave radiation (LWR) from open waters can and has been called a negative feedback working against Arctic amplification as opposed to the positive feedback of increased albedo during peak insolation.

But it turns out that increased LWR is neither a "proper" nor a "non-proper" negative feedback at all. It seems that heat loss from ice-free waters outside of peak insolation is itself the positive feedback that I and many others assumed was simply linked to higher albedo during peak insolation. Turns out that the two are inexorably linked, with increased albedo being a primary cause and increased LWR the proximate cause in Arctic amplification (with loss of sea ice being the root cause).

So the mental equation goes from:

Code: [Select]
(increased insolation as positive feedback ) - (increased LWR as negative feedback) = ?
where ? is either positive or negative but always smaller than the positive feedback of increased insolation, to the following:

Code: [Select]
Increased insolation => increased LWR => increased temperature
No negative feedback, only a positive feedback loop. Which to my mind makes a big difference.
Title: Re: The 2020/2021 freezing season
Post by: oren on October 09, 2020, 10:34:18 AM
Binntho, I admit I cannot figure out if the above is sarcastic or not, but if it is then please avoid that. If not then ignore this comment.
Title: Re: The 2020/2021 freezing season
Post by: SimonF92 on October 09, 2020, 11:01:22 AM
Thank you for the stimulating discussion points everyone. A-team, its good to see you post in these threads, I follow you closely on the MOSAIC thread.

Reminds me of an article I wrote last year for my uni's student mag. I struggled to pitch it to a correct level and tie it up in so few words, but they really liked it and put it in their print edition too.

https://the-gist.org/2019/10/the-problem-with-arctic-amplification/

Title: Re: The 2020/2021 freezing season
Post by: binntho on October 09, 2020, 11:17:26 AM
Binntho, I admit I cannot figure out if the above is sarcastic or not, but if it is then please avoid that. If not then ignore this comment.

Well it's not sarcastic on purpose! Although I agree with most of what you said, I still felt it necessary to clarify the point that LWR is apparently not a negative feedback. I was unable to read that from your comment, your dismissal of LWR as being not a "proper" negative feedback indicated that you still understood it as a negative feedback in some sense.

I started this discussion several posts back after a couple of posts from other users who (as so many of us both this autumn and practically every year before that) were saying or wondering about the negative feedback of so much open water going into the polar night.

A-Team's post opened my eyes to the fact that it is actually the other way around: Open water during the polar night *is* the positive feedback, the ultimate cause of Arctic amplification. To me this seems a very important distinction, and from my reading of the posts of other members, not something that everybody has understood. Including, it seemed to me, yourself.
Title: Re: The 2020/2021 freezing season
Post by: oren on October 09, 2020, 11:57:57 AM
Thanks for the clarification!
Title: Re: The 2020/2021 freezing season
Post by: Freegrass on October 09, 2020, 01:50:13 PM
Latest Five Day Forecast
Wind + Temp @ Surface
Large GiF!
Title: Re: The 2020/2021 freezing season
Post by: jens on October 09, 2020, 02:27:04 PM
Forgot to mention, but 2018 is also an example of the recent trend of a slow refreeze in October, despite not having a particularly low September minimum. Currently 2012 is (still) in the lead, but 2020, 2019 and 2018 are all right after it in next positions.

And also interesting to see, how big the gaps could be stretched out. 2010's average is losing by a whole 1M km2 to 2020 now. 8th position (2017) is 1.3M down on 2020. At some point of course gaps will start coming down again, so let's see how long does it take before it happens.
Title: Re: The 2020/2021 freezing season
Post by: gerontocrat on October 09, 2020, 02:35:05 PM
Laptev Sea Ice Area & Extent

Lots of posts about whether ocean heat will keep the Arctic ice-free all winter. Perhaps the Laptev will give us some clues...

Siberian heatwave + early and rapid record melting gives extreme Alebedo Warming Potential (AWP).

Then add the GACC at exactlly the right time to convert Albedo Warming Potential into far above average real ocean heating.

Result - something approaching the maximum possible ocean heat in the Laptev Sea given the current Arctic climate.

So for how long will the Laptev resist re-freeze?
Title: Re: The 2020/2021 freezing season
Post by: SimonF92 on October 09, 2020, 04:05:35 PM
Evidence of sea ice formation at Protoka Ularova in Yakutiya (ESS) today
Title: Re: The 2020/2021 freezing season
Post by: sailor on October 09, 2020, 05:07:33 PM

Like the Yermak, Barents too receives a branch of Atlantic Water inflows and has largely lost its stratification (previously maintained by fresh water from ice melt); in terms of wind mixing, over a third of the Arctic Ocean (mostly on the Siberian side) has shallower water than the ~300m deep Barents.

The Bering Sea too no longer freezes over in winter despite large water exchanges with the Chukchi -- which still has open water on Jan 1st in recent years. The Chukchi is well over a thousand km south of the Barents and only partly above the Arctic Circle.

There are no instances over the last 7 years of Jan 1st open water in the ESS or Laptev. This year bears watching however for open water persisting after mid-November because of the cumulative impact of double diffusion of Atlantic Waters over the years and the massive solar heat input this July to early low albedo open waters of the Laptev.

The AW brings in enough heat each year to melt all the ice, the question has always been how much of that heat it leaves behind -- more and more per Mercator Ocean and Laptev moorings (Polyakov 2019).

It should not be assumed that all the open water in the Arctic Basin will magically refreeze in winter. As time goes on, more and more open water will persist later and later into the depths of winter. A lot of blackbody radiation (Planck effect) comes right back down so it doesn't have the cooling effect that one might imagine.


Well, thank you A-Team as always! It seems that my understanding of the late-refreeze negative feedback is outdated, or, to say the least, this negative feedback comes accompanied by other positive feedbacks due to winter weather disruption (like 2016/2017 that resulted in the thinnest ice that has been seen out of a Winter). Will be interesting to see what is going on this freezing season.

Title: Re: The 2020/2021 freezing season
Post by: Tor Bejnar on October 09, 2020, 05:21:29 PM
...
https://the-gist.org/2019/10/the-problem-with-arctic-amplification/
Very nicely written, Simon.  You got the 'water vapor from the South' part, but missed (with most of the rest of us) the 'local water vapor where there isn't as much (or any) sea ice' part.
Genetics?  :)
Title: Re: The 2020/2021 freezing season
Post by: dnem on October 09, 2020, 06:05:01 PM
Binntho, I admit I cannot figure out if the above is sarcastic or not, but if it is then please avoid that. If not then ignore this comment.
A-Team's post opened my eyes to the fact that it is actually the other way around: Open water during the polar night *is* the positive feedback, the ultimate cause of Arctic amplification. To me this seems a very important distinction, and from my reading of the posts of other members, not something that everybody has understood. Including, it seemed to me, yourself.

I'm not sure about this, and I'd like to hear A-Team's take. It seems to me that many of A-Team's partial BOE posts argue strongly for the accumulated, summer, albedo-driven energy gain caused by ever earlier open water as a massive positive feedback and cause/example of arctic amplification.

I read the above post as simply arguing that expecting all this accumulated energy to be quickly and harmlessly "vented to space" during the arctic night is misguided.

FWIW, the "open water heading into the arctic night = GOOD" argument has always struck me as a violation of Occam's Razor: Less ice, more open water, later and later into the fall just does not seem "good" to me. 
Title: Re: The 2020/2021 freezing season
Post by: binntho on October 09, 2020, 06:34:06 PM
... It seems to me that many of A-Team's partial BOE posts argue strongly for the accumulated, summer, albedo-driven energy gain caused by ever earlier open water as a massive positive feedback and cause/example of arctic amplification. ...

I'd be the first to admit to having misunderstood the whole thing! But here is a simple version of my naive understanding of the insolation / LWR / negative vs. positive feedback thing.

To begin with, we are talking about Arctic amplification, or the fact that the Arctic warms up faster than the rest of the globe. This is valid during our current antrophogenic warming, and was also something that happened during the last interglacial.

The standard explanation, as also repeatedly expounded by A-Team, is that less sea ice means lower albedo during peak insolation which again means that a lot more heat is absorbed by the ice-free parts of the Arctic ocean. And of course, that is exactly the correct explanation for the Arctic amplification.

But the addendum missing from the explanation is that getting extra energy into open waters during the short period of peak insolation every summer is not enough to explain the Arctic amplification which is a year-round phenomenon, raised air temperatures rather than increased ocean heat content. Lower albedo is only playing the leading role, the second and equally necessary part is played by open ocean going into the polar night, the side-kick that I and probably a lot of other people have not realised was there.

The open waters radiate the extra heat out as long-wave radiation, while at the same time contributing strongly to an isolating blanket of clouds and water vapor. The heat does of course eventually escape into space, but not before causing that good old Arctic amplification and enabling it to linger well into winter.

Which is totally opposite the claim that sees having more open water going into the polar night as some sort of negative feedback working against the Arctic amplification caused by lower albedo during peak insolation. Which was what started the whole discussion.
Title: Re: The 2020/2021 freezing season
Post by: gandul on October 09, 2020, 07:58:53 PM
FWIW, the "open water heading into the arctic night = GOOD" argument has always struck me as a violation of Occam's Razor: Less ice, more open water, later and later into the fall just does not seem "good" to me.
It’s not that it is good. It is that there are physical reasons (Stefan-Boltzmann Law) to expect that the more energy you make available now, the more energy will radiate out to space during the NH night.

The net effect is energy loss and therefore another factor to moderate, rather than precipitate, the decline of sea ice in the years to come.

A-Team is conflating this negative feedback effect that he, as scientist, knows well, with other atmospheric effects which are less clear and of more conjectural nature, to produce an overtly alarming picture.
Title: Re: The 2020/2021 freezing season
Post by: aslan on October 09, 2020, 08:16:46 PM
It’s not that it is good. It is that there are physical reasons (Stefan-Boltzmann Law) to expect that the more energy you make available now, the more energy will radiate out to space during the NH night.

It's you who are confusing the whole thing. Plank feedback (function of T^4) is well known but others feedback also: lapse rate, water vapor, clouds, etc. Overall, climate sensitivity is 3 degres to doubling co2. Nothing new. With your reasoning, more co2 would mean a cooling earth. Open arctic in winter is stable state. Point in case: barents and bering sea, kara sea in 2012 and 2016, likely laptev sea winter 2021. You are pushing this topic off road with unbased statement. Open arctic in winter is definitively not a giant radiator cooling down the earth. It is a stable system from an energy POV.
Title: Re: The 2020/2021 freezing season
Post by: Glen Koehler on October 09, 2020, 08:37:18 PM
<snip> Open water during the polar night *is* the positive feedback, the ultimate cause of Arctic amplification.
   But surely increased Long wave radiation outward from the ocean does result in increase of energy exported out of the system into space.  Not all of it is captured in the atmosphere to contribute to Arctic amplification.  Therefore, to some extent open water ---> increased LWR ---> is to some degree a negative feedback that works to stabilize Arctic energy balance.

    Granted all that LWR does not immediately leave the system, and can cause intermediate effects such as warming the overlying blanket of air and water vapor along the way.  Thus, there are feedbacks within the larger open water --- LWR feedback.  But the net effect of greater LWR emission has to result in more energy leaving the system eventually, and thus to some degree serve as a negative feedback.
Title: Re: The 2020/2021 freezing season
Post by: I’M IN LOVE WITH A RAGER on October 09, 2020, 10:05:19 PM
Sure it might increase LWR emission, but I highly doubt it increases enough to reduce the energy in the system to a quantity lower than that of previous years where ice was already freezing in many of these anomalously warm areas. Even if all of the excess energy absorbed by the basin this summer left the system and it returned to an “average” heat content, wouldn’t it just return to average freezing progression, not somehow increase freezing? I fail to see how this energy SURPLUS is going to result in a DEFICIT come next melting season. If that were the case, warm water could freeze faster after being heated in the sun all day after being tossed into a freezer than room temperate water in the same freezer. Completely illogical. The sun-warmed cup might release more LWR because it has more energy to give, but it’s not going to pass the room temp cup in thermal energy content and reach a lower state under the same conditions and same timeframe. That’s not how thermodynamics works. Obviously the room temp cup starts freezing faster and freezes deeper in the same temporal stretch than the sun-warmed cup.
Title: Re: The 2020/2021 freezing season
Post by: Glen Koehler on October 09, 2020, 11:32:32 PM
     Of course adding heat is not going to make the Arctic get colder.  That is not what I said and is not implied by the term negative feedback.  My point was that an energy increase that results in more open water that results in increased LWR that results in increased energy lost from the system will have a negative feedback effect to partially counteract that initial energy addition.  That influence would act to partially revert back to the initial energy state but not go below it. 

     Unless a negative feedback is 100% effective (unlikely if not impossible without some other state change), it will not cause a system to even get all the way back to the initial state.  Adding energy to a system increases the energy in that system.  But a negative feedback acts to make the net gain in energy somewhat less than the initial value plus the added amount.  As the negative feedback acts to bring the system back towards and closer to the intial energy state,  the weaker that negative feedback becomes, so the system can't end up being less energetic than it was initially.  (And now somebody can point out some chemical system etc. where negative feedbacks can indeed overun and go below the initial state, but I can't see how that could possibly apply in a large complex system like the Arctic Ocean.)

     My point was that I think binntho was overreacting to his epiphany from A-Team.  Increased LWR can have some effects on air temperature or water vapor on its way toward space, but some portion of that additional long wave radiation will go into space, thus leaving the Arctic system.  That loss will cause energy loss from the system and, to some degree, that loss will function as a negative feedback on system energy level, i.e. warming.  Sorry if I am being pedantic, but your response so completely missed my point that I feel the need to be as explicit as possible.
Title: Re: The 2020/2021 freezing season
Post by: I’M IN LOVE WITH A RAGER on October 09, 2020, 11:53:45 PM
For sure Glen, that makes sense. I definitely recognize that negative feedback loops are most often stabilizing/homeostatic in direction whereas positive feedback loops are most often accelerationary and divergent from baseline in direction. I wasn’t so much responding to what you were saying as much as some others in the thread who were implying the Arctic would be colder. I think you and I are on the same page, and I agree completely with what you said.
Title: Re: The 2020/2021 freezing season
Post by: Glen Koehler on October 09, 2020, 11:57:43 PM
    Let there be peace.  And may the record show that in this very short-term debate there was no fly from Satan perched on my perfectly groomed head: https://twitter.com/DailyCaller/status/1314201685292658689?ref_src=twsrc%5Etfw%7Ctwcamp%5Etweetembed%7Ctwterm%5E1314202216316776448%7Ctwgr%5Eshare_3&ref_url=https%3A%2F%2Fthehill.com%2Fhomenews%2Fmedia%2F520201-lincoln-projects-schmidt-fly-on-pences-head-historically-a-mark-of-the-devil (https://twitter.com/DailyCaller/status/1314201685292658689?ref_src=twsrc%5Etfw%7Ctwcamp%5Etweetembed%7Ctwterm%5E1314202216316776448%7Ctwgr%5Eshare_3&ref_url=https%3A%2F%2Fthehill.com%2Fhomenews%2Fmedia%2F520201-lincoln-projects-schmidt-fly-on-pences-head-historically-a-mark-of-the-devil)
Title: Re: The 2020/2021 freezing season
Post by: kassy on October 10, 2020, 12:08:30 AM
FWIW, the "open water heading into the arctic night = GOOD" argument has always struck me as a violation of Occam's Razor: Less ice, more open water, later and later into the fall just does not seem "good" to me.
It’s not that it is good. It is that there are physical reasons (Stefan-Boltzmann Law) to expect that the more energy you make available now, the more energy will radiate out to space during the NH night.

The net effect is energy loss and therefore another factor to moderate, rather than precipitate, the decline of sea ice in the years to come.

A-Team is conflating this negative feedback effect that he, as scientist, knows well, with other atmospheric effects which are less clear and of more conjectural nature, to produce an overtly alarming picture.

The arctic night is always roughly similar yet we can have very different climate states as the past has shown.
Title: Re: The 2020/2021 freezing season
Post by: jdallen on October 10, 2020, 03:12:19 AM
FWIW, the "open water heading into the arctic night = GOOD" argument has always struck me as a violation of Occam's Razor: Less ice, more open water, later and later into the fall just does not seem "good" to me.
It’s not that it is good. It is that there are physical reasons (Stefan-Boltzmann Law) to expect that the more energy you make available now, the more energy will radiate out to space during the NH night.

The net effect is energy loss and therefore another factor to moderate, rather than precipitate, the decline of sea ice in the years to come.

A-Team is conflating this negative feedback effect that he, as scientist, knows well, with other atmospheric effects which are less clear and of more conjectural nature, to produce an overtly alarming picture.
I'll disagree mildly with the last and bolded, and to a lesser degree with how you characterize A-Team's method.

I really can't remember in 7 years where he's seriously overstated an effect or mechanism.

Or even modestly for that matter.

Frankly, I think it is hard to understate the likely impact of warming of the Laptev, ESS, Barents and Kara in particular that took place during the melting season.

I think it's hard to understate the impact of the breakdown of stratification in the peripheral seas on the Atlantic side, along with the enormous influx of heat that's being pulled along by "Atlantification".

Other posters have correctly pointed out that outgoing black body radiation will not be able to dump the heat that's been accumulated, and is *still* being imported by southerlies pulling storms, heat and moisture into the basin from further south.

I think it bears serious watching, as my "hunch" at this point is we will see an extremely anemic refreeze, with a significant reduction in end of refreeze volume, even if those peripheral seas appear to refreeze robustly.  I think the portents for next year are very serious indeed.

Edit:  What we need, desperately, this winter:

- A strong polar vortex
- Crystal clear skies
- Minimal snow on the pack

I'm pessimistic about the probability of any of them.
Title: Re: The 2020/2021 freezing season
Post by: binntho on October 10, 2020, 05:40:47 AM
     My point was that I think binntho was overreacting to his epiphany from A-Team.  Increased LWR can have some effects on air temperature or water vapor on its way toward space, but some portion of that additional long wave radiation will go into space, thus leaving the Arctic system.  That loss will cause energy loss from the system and, to some degree, that loss will function as a negative feedback on system energy level, i.e. warming.  Sorry if I am being pedantic, but your response so completely missed my point that I feel the need to be as explicit as possible.

Not being big on epiphanies in general, perhaps I did overreact.

But it seems to me that a fundamental point is missing here, Glen, which is that all incoming energy from the sun radiates out to space again eventually.

Arctic amplification is an added warming of the Arctic atmosphere that is caused by extra heat being released from the open ocean, whether by conduction or radiation. But all the heat released will radiate out to space eventually. Atmospheric green-house gases delay the release of energy, but do not stop it, causing the global atmospheric temperature to be almost 30 degrees higher than it would otherwise be (and rising). Local Arctic cloud blanketing adds significantly to delaying the energy on its way out to space but does not stop the energy from radiating out eventually.

Arctic amplification indicates an imbalance in the distribution of Arctic insolation energy (as do other amplifications, such as dry land amplification and continental amplification). Arctic amplification is caused by the energy added during peak insolation being released *locally* rather than joining the global oceanic circulation.

Increased LWR out to space is therefore a proxy for increased atmospheric temperatures. Arctic amplification implies more LWR radiation out to space. Increased LWR is a result of Arctic amplification.

Long Wave Radiation is thus not a negative feedback at all. It simply reflects incoming energy. The delay in the escape of energy from the atmosphere is what raises atmospheric temperatures, but the amount of energy released will always match the incoming (in the long run of course, in a warming world some energy is retained until a balance is re-established).
Title: Re: The 2020/2021 freezing season
Post by: Aluminium on October 10, 2020, 07:33:35 AM
LWR is main negative feedback which stabilizes temperature on the Earth and prevents violation of the second law of thermodynamics. Warmer -> more LWR -> cooling. Cooler -> less LWR -> warming. Increased LWR can be a result of positive feedback but it provides negative feedback itself.
Title: Re: The 2020/2021 freezing season
Post by: Aluminium on October 10, 2020, 07:38:25 AM
October 5-9.

2019 (https://forum.arctic-sea-ice.net/index.php/topic,2888.msg232707.html#msg232707).
Title: Re: The 2020/2021 freezing season
Post by: binntho on October 10, 2020, 07:49:27 AM
LWR is main negative feedback which stabilizes temperature on the Earth and prevents violation of the second law of thermodynamics. Warmer -> more LWR -> cooling. Cooler -> less LWR -> warming. Increased LWR can be a result of positive feedback but it provides negative feedback itself.

Perhaps we need to find a better definition of terms here. Feedback is when something is fed back into the system, and outgoing LWR radiation is obviously not fed back. So by that definition it is not a feedback, neither negative nor positive.

Solar insolation is not a feedback either. It is an input. Outgoing LWR is an output.

Increasingly open waters during maximum insolation are a result of global warming, and by themselves cause even faster warming. A typical postive feedback. And then some people would like to say that this is countered by the increased outgoing LWR caused by the same open waters going into the polar night, effectively saying that open waters are a positie feedback during peak insolation, and a negative feedback during the polar night.

But this is a misunderstanding. Open waters going into the polar night are the mechanism by which the added energy during peak insolation is released back to the atmosphere, thereby contributing to Arctic Amplification. All energy released to the atmosphere ends up leaving into space via LWR amyway, the difference here being where the energy is released, i.e in the Arctic as opposed to elsewhere.

And this turns the open waters into a positive feedback during the polar night. Without the open waters, the insulating blanket would be much thinner and the amount of energy in the atmosphere would be much less. The ice would freeze much faster and become thicker. But because of the open waters, the energy added into the ocean during peak insolation is allowed to escape into the atmosphere, raising humidity and temperatures. The fact that it eventually escapes into space is meaningless in this context.
Title: Re: The 2020/2021 freezing season
Post by: S.Pansa on October 10, 2020, 08:56:50 AM
I guess we are veering way off topic here but here is a quote from a standard textbook on the basic science of global warming, David Archers "Global Warming. Understanding the forecast".

In chapter 7, p 73 f he writes:
Quote
A feedback is a loop of cause and effect (Figure 7-1). At the center of a feedback is a state
variable. The state variable in many of the climate feedback loops in this book is the average
temperature of the Earth. To see a feedback in action, drive the temperature a bit by changing
some external factor, like the intensity of the sun. A positive feedback makes the temperature
change larger than it would have been without the feedback, amplifying the temperature change.
A negative feedback counteracts some of the external forcing, tending to stabilize the state
variable. ... A negative feedback is a stabilizer. The drain in the kitchen sink analogy has a
negative feedback to the water level. ... A positive feedback is an amplifier.

He also names a few examples, explained in the attached figure 7-1

An the NASA writes  (https://climate.nasa.gov/nasa_science/science/)
Quote
Climate feedbacks: processes that can either amplify or diminish the effects of climate forcings. A feedback that increases an initial warming is called a "positive feedback." A feedback that reduces an initial warming is a "negative feedback."

What I find strange is - I am with aslan here - that some people are calling well known atmospheric effects "less clear and of more conjectural nature". The greenhouse effect would be totally different without the influence of clouds, water vapor, lapse rate, moist convection ... imho they are not conjectural but basic (basic text-book stuff actually).

Just one example, again  from David Archer (p 62 and fig 6-5):
Quote
Even when averaging out the seasonal cycle, the radiative energy budget of a single spot on the surface of the Earth is still probably way out of balance, because heat energy is redistributed around the Earth’s surface by wind and water currents (Figure 6-5). There is a net influx of heat in the tropics as sunlight brings in energy faster than the outgoing IR. It does not get hot enough in the tropics for outgoing IR to balance the incoming sunlight locally. Heat is carried into the cooler high latitudes by warm winds and ocean currents. In high latitudes, the Earth vents the excess tropical heat as excess radiative heat loss to space.

Did I say I think I am going off-topic?  :-[
Title: Re: The 2020/2021 freezing season
Post by: binntho on October 10, 2020, 09:40:58 AM
Thanks for that input S. Pansa. As to whether we are off topic or not ... it is topical in the sense that we are discussing things that are happening during this freezing season. But then again, it is a discussion of fundamentals which perhaps should belong elsewhere.

As for how we define feedbacks - I do not agree with David Archers' inclusion of the drain in the kitchen sink. It is not a negative feedback, it is simply the output of the system. Same goes for the spout, it is not a positive feedback, it is the input to the system.

A feedback has to feed back! There must be a re-entry of some sort, a circular causation. In the sink example, a positive feedback would be something that caused the water level to rise faster than the inflow of water could explain on its own and should be caused by the inflow of water. A pressure seal that becomes more efficient with increased pressure could be an example of a positive feedback. In scenario A, the system is in equilibrium. In scenario B, the inflow rate has increased and the water level rises to compensate, but the positive feedback of the pressure seal leads to scenario C where the equilibrium level is pushed higher than would otherwise have been the case based on the increased input alone.

In our case, the positive feedback is the presence of open water which is caused by increased temperatures, but at the same time causes temperatures to rise even further in a limited area (i.e. Arctic amplification). The mechanism involved is lower albedo during peak insolation, and a commensurately larger loss of heat during autumn and winter combined with a blanketing effect. Any increase in outgoing LWR simply shows that the positive feedback is active!
Title: Re: The 2020/2021 freezing season
Post by: oren on October 10, 2020, 10:19:40 AM
Folks, an interesting discussion but when too long it becomes off-topic. I suggest we have covered the issue well and there seems to be a general agreement - the extra added energy in the system (from sun-albedo and from lower latitude transport) is (mostly) released during winter, with open water serving as a main release mechanism. This release is causing climate-changing winter effects, leading to higher temps and lower overall ice growth. The mechanism is not expected to lead to a colder winter or thicker ice, compared with a normal year. Further discussion can be taken elsewhere, where it will better survive the test of time.

Also another request, please don't start discussing specific posters. Discuss science, not persons.
Title: Re: The 2020/2021 freezing season
Post by: BornFromTheVoid on October 10, 2020, 01:03:26 PM
Slow animation from the last 5 days.

Title: Re: The 2020/2021 freezing season
Post by: Freegrass on October 10, 2020, 01:48:38 PM
Latest Five Day Forecast
Wind @ Surface + Total Precipitable Water
Wind + Temp @ 850hPa
Large GiFS!

A fresh dash of warm air coming in from the Pacific it seems...
Title: Re: The 2020/2021 freezing season
Post by: gandul on October 10, 2020, 01:54:35 PM
In one week we’ll have the perfect radiator to space. Warm stirred open ocean under a wide open dark sky.
Title: Re: The 2020/2021 freezing season
Post by: gandul on October 10, 2020, 02:26:48 PM
Just to briefly respond in general, I was not saying it is an overwhelming effect but something that helps the Arctic ice loss not to be faster than it really is. Let’s not willfully count only with the warming-enhancing effects.

Also @binntho: there is an extra delta heat that can be lost if open wide ocean is being stirred, subsurface ocean heat that otherwise would remain buried at least until next season, it’s not just heat lost due to extra temperature, it’s the delta heat loss caused by ice loss. It is an internal restorative force. If there was no delta extra heat loss due to ice loss, it wouldn’t be a feedback.
What you describe is not, I agree.
Title: Re: The 2020/2021 freezing season
Post by: BornFromTheVoid on October 10, 2020, 03:42:04 PM
I decided to measure the changes in the ice edge position, starting at the daily minimum.
For now, it's the ice edge position (first instance of open water) or where the ice is at its maximum extent (such as N of Greenland or along sections of the Arctic ocean coasts in some years) that's measured. Measurements are done every 5 degrees, but also grouped for stats on edges facing individual seas.

(Ideally, I could do something like this for every day of the year, all years, but that's gonna be some way down the road when my python skills have improved a lot!)

I've only done 79 to 89 so far, and the closest ice edge position, by far, was in 1979, at 678 km at 50 degrees east.
On average, the minimum with the closest ice edge position was 1984, averaging 1330 km.
I'll get it updated to 2020 during the week, hopefully, and do the maxima after that. For now, here's just a sample with 1979 to 1989.

Comments/suggestion welcome as always.
Title: Re: The 2020/2021 freezing season
Post by: Wildcatter on October 10, 2020, 04:24:54 PM
Haha, yeah I saw that forecast (for 17th). Look at those isobars  :P 

So, in about 4 days, euro and GFS in pretty good agreement, high sets up and brings some heavy winds and warmer temps across the Chukchi and siberian seas, some moisture, goes on for about 4 more days (so 8 days from now), models start to diverge there. If that comes to pass, I imagine it has some stalling effect on ice re-growth. Maybe not. I'll go with an unequivocal, "probably". Ironclad.

GFS has 4.5-4.8C Arctic temp anomalies for the 13th-17th (relative to '79-2000), that open water pretty extreme anomalies. I just use climatereanalyzer hourly forecast for temp anomalies, uses GFS, can go see if it you're curious. https://climatereanalyzer.org/ (https://climatereanalyzer.org/)  on left-hand side, click "hourly forecast", change "Forecast Model" dropdown to GFS global, "Map Area" to Arctic, and "Variable Dropdown" to 2m temp anomaly, and there's some other variables you can peruse at your leisure.

And just as a reference, to throw some freeze season extent numbers out there, a comparison to 2019 on October 17th, just picked that day because it was top of mind

8 days worth of measurements (km2)
On 17th: 2019 = 5.24 million
Today: 2020 = 4.47 million
2020 has to average ~96,000 extent gain a day to recover past 2019s low (or 2020 will be lowest)

Might be pretty tough if that setup plays out. Just something to keep an eye on, and models could change completely in a few days so there's the disclaimer.  :D
Title: Re: The 2020/2021 freezing season
Post by: gerontocrat on October 10, 2020, 04:46:32 PM
The 10 year average daily gain will reach the maximum of well over 125k per day from about the 16th of October.

Trouble is, some years are late re-freeze, some early.
Title: Re: The 2020/2021 freezing season
Post by: Tor Bejnar on October 10, 2020, 04:51:37 PM
Could somebody graph extent data deltas (difference from minimum for that year) from Sept. 15 onward?  My guess is that more recent years' data will have a lower slope than earlier years.  2020 appears to have very slow growth.

Thanks in advance (and hoping ...)  [edit:  like what Gero just posted, only starting on Sept. 15]
Title: Re: The 2020/2021 freezing season
Post by: dosibl on October 10, 2020, 05:09:10 PM
Looking at the average sea level pressure anomaly as a proxy for clearer skies during the peak AWP dates in the Laptev / ESS (~6/15-8/1), lines up decently with the large SST anomaly there now. Will be interesting to see what happens there over the next month.
Title: Re: The 2020/2021 freezing season
Post by: Comradez on October 10, 2020, 05:48:12 PM
Interesting figures, S.Pansa!  Is there a particular reason why, in Figure 6-5, the incoming and outgoing radiation don't seem to net to zero globally?  (Just eyeballing it, it looks like there's no way the areas under the curves match).
Title: Re: The 2020/2021 freezing season
Post by: Peter Ellis on October 10, 2020, 07:04:18 PM
Interesting figures, S.Pansa!  Is there a particular reason why, in Figure 6-5, the incoming and outgoing radiation don't seem to net to zero globally?  (Just eyeballing it, it looks like there's no way the areas under the curves match).
Remember that the total area from (say) 0-10 degrees north is MUCH larger than the area from 80-90 degrees north.
Title: Re: The 2020/2021 freezing season
Post by: Freegrass on October 11, 2020, 01:32:34 PM
Latest Five Day Forecast
Wind + Temp @ Surface
Large GiF!
Title: Re: The 2020/2021 freezing season
Post by: oren on October 11, 2020, 01:42:04 PM
Latest Five Day Forecast
Wind + Temp @ Surface
Large GiF!
The central Beaufort should finally see surface freeze, and the tail should lose its shape (already begun yesterday), thanks to the very low temps. However big trouble is coming from Laptev and the ESS, with some temps even rising above zero. So not much growth this coming week. 2020 will probably be lowest on record in both area and extent.
Title: Re: The 2020/2021 freezing season
Post by: uniquorn on October 11, 2020, 11:02:23 PM
Just a hint of coastal refreeze in parts of the Lena delta on worldview. Quite a change from sep23. (click for ani)

polarview, oct10

Oddly enough, further north it still looks like melt season.
Title: Re: The 2020/2021 freezing season
Post by: Pagophilus on October 11, 2020, 11:41:28 PM
Just a hint of coastal refreeze in parts of the Lena delta on worldview. Quite a change from sep23. (click for ani)

polarview, oct10

Oddly enough, further north it still looks like melt season.
Maybe because there is a freshwater layer capping the sea around the Lena's mouths, but saltier water at the surface further out? 
Thanks for these images. 
Title: Re: The 2020/2021 freezing season
Post by: SimonF92 on October 12, 2020, 01:00:31 AM
Cold air is blowing off the continent, its just colder closer to shore
Title: Re: The 2020/2021 freezing season
Post by: Aluminium on October 12, 2020, 07:37:41 AM
October 7-11.

2019 (https://forum.arctic-sea-ice.net/index.php/topic,2888.msg232923.html#msg232923).
Title: Re: The 2020/2021 freezing season
Post by: morganism on October 12, 2020, 08:14:18 AM
edit: oops
Title: Re: The 2020/2021 freezing season
Post by: uniquorn on October 12, 2020, 11:33:01 AM
Thanks for the SMOS post. As we suspected, all that MYI exported to the Beaufort tail has nearly melted out, and will give no resilience against next year's melting season.
It effectively amounts to open water except energy to refreeze further area is closer to zero.
For practical purposes Beaufort sea is free of MYI facing the refreeze season

It will be interesting to see what the NSIDC ice age update looks like. Here is a polarview S1A of the stalwart MYI floe at the centre of the amsr2 inset (awi v103). It's looking somewhat rounded, so has probably not had an easy time during the melting season.   ~300km2, maybe it will show up on cryosat2 if it doesn't drift too quickly.
Quote
CryoSat-2 will achieve improved spatial resolution of 250 m in the along-track direction using the Synthetic Aperture technique.
https://earth.esa.int/web/guest/missions/esa-operational-eo-missions/cryosat/overview
Title: Re: The 2020/2021 freezing season
Post by: Freegrass on October 12, 2020, 01:46:17 PM
Latest Five Day Forecast
Wind @ Surface + Total Precipitable Water
Wind + Temp @ 850hPa
Wind @ 250hPa
Large GiFS!

High pressure in the Arctic with high temperatures and lots of the greenhouse gas moisture to keep all that heat in... How unusual is that for this time of year?
Title: Re: The 2020/2021 freezing season
Post by: harpy on October 12, 2020, 03:02:47 PM
Thanks for that input S. Pansa. As to whether we are off topic or not ... it is topical in the sense that we are discussing things that are happening during this freezing season. But then again, it is a discussion of fundamentals which perhaps should belong elsewhere.

As for how we define feedbacks - I do not agree with David Archers' inclusion of the drain in the kitchen sink. It is not a negative feedback, it is simply the output of the system. Same goes for the spout, it is not a positive feedback, it is the input to the system.

A feedback has to feed back! There must be a re-entry of some sort, a circular causation. In the sink example, a positive feedback would be something that caused the water level to rise faster than the inflow of water could explain on its own and should be caused by the inflow of water. A pressure seal that becomes more efficient with increased pressure could be an example of a positive feedback. In scenario A, the system is in equilibrium. In scenario B, the inflow rate has increased and the water level rises to compensate, but the positive feedback of the pressure seal leads to scenario C where the equilibrium level is pushed higher than would otherwise have been the case based on the increased input alone.

In our case, the positive feedback is the presence of open water which is caused by increased temperatures, but at the same time causes temperatures to rise even further in a limited area (i.e. Arctic amplification). The mechanism involved is lower albedo during peak insolation, and a commensurately larger loss of heat during autumn and winter combined with a blanketing effect. Any increase in outgoing LWR simply shows that the positive feedback is active!


Excellent post, thank you.
Title: Re: The 2020/2021 freezing season
Post by: The Walrus on October 12, 2020, 03:23:07 PM
Yes, much of what people refer to as feedback is not so (even though the influence the system).  Cloud cover is a prime example.  Blocking incoming solar radiation during the day is not feedback, but reflecting radiation earthward at night is.  However, changing the cloud cover, due to climate change would be a feedback.  Same with the open water.
Title: Re: The 2020/2021 freezing season
Post by: Freegrass on October 13, 2020, 01:46:47 PM
Latest Five Day Forecast
Wind + Temp @ Surface
Large GiF!
Title: Re: The 2020/2021 freezing season
Post by: gandul on October 13, 2020, 02:00:18 PM
Impressive waves predicted for this saturday, being the Arctic in October (ECMWF)
Title: Re: The 2020/2021 freezing season
Post by: Positive retroaction on October 13, 2020, 02:58:51 PM
Could the edge on the laptev / ESS side, which is already struggling to progress, decrease?
It will also depend on the frequency of the waves, right?
Title: Re: The 2020/2021 freezing season
Post by: gandul on October 13, 2020, 07:43:54 PM
Could the edge on the laptev / ESS side, which is already struggling to progress, decrease?
It will also depend on the frequency of the waves, right?
No idea, I’d say it’s too cold but who knows.

But it’s the perfect weather to unbury lots of heat, at least the first few meters of ocean sub-surface are susceptible to waves caused by 20 kt winds or so, and quite a lot of fetch to generate some mechanical energy that gets deep a few meters.

Actually the weather has not been quiet at all since september so this is an ongoing situation.
Title: Re: The 2020/2021 freezing season
Post by: A-Team on October 13, 2020, 10:58:55 PM
Quote
No idea, I’d say it’s too cold
I would say it's far too warm between the ice pack and the entire Siberian side to even be considering refreezing inroads by Nov 1st. The southern limit of ice has hardly budged since Oct 1st (magenta line) so still has 1200 km to go. The sea surface temperature anomalies are remarkable today and even out nine days to Oct 22nd, per Mercator Ocean.

An immense volume of warm water is still several degrees above the freezing point of salt water from the surface to a depth of 30+m, again out to Oct 22nd, making for some 90,000 cubic km of sea water needing to be cooled (if vertically mixed) by air having only a thousandth the specific heat capacity.

A delayed freeze has significant consequences in terms of thinner, brine pockety ice by spring like it did last year in the wake of the extreme TransPolar Drift

The Chukchi is even slated to get warmer towards the end of the month from incoming advection of yet warmer waters from the Bering Sea. At this rate, the southern Chukchi will remain open water into early or even mid January.

Weakening of Cold Halocline Layer Exposes Sea Ice to Oceanic Heat in the Eastern Arctic Ocean
IV Polyakov, T Rippeth et al
J. Climate (2020) 33 (18): 8107–8123.
https://journals.ametsoc.org/jcli/article/33/18/8107/353233 free full

"The upward release of AW heat is regulated by the stability of the overlying halocline, which we show has weakened substantially in recent years. Shoaling of the AW has also contributed, with observations in winter 2017–18 showing AW at only 80 m depth, just below the wintertime surface mixed layer, the shallowest in our mooring records. The weakening of the halocline for several months at this time implies that AW heat was linked to winter convection associated with brine rejection during sea ice formation. This resulted in a substantial increase of upward oceanic heat flux during the winter season, from an average of 3–4 W m−2 in 2007–08 to >10 W m−2 in 2016–18. This seasonal AW heat loss in the eastern EB is equivalent to a more than a twofold reduction of winter ice growth. These changes imply a positive feedback as reduced sea ice cover permits increased mixing, augmenting the summer-dominated ice-albedo feedback."

Greater role for Atlantic inflows on sea-ice loss in the Eurasian Basin of the Arctic Ocean
IV Polyakov et al
Science  21 Apr 2017
https://science.sciencemag.org/content/356/6335/285.full  free full

Arctic sea ice is being increasingly melted from below by warming Atlantic water
Tom Rippeth  Prof Physical Oceanography, Bangor ME
September 18, 2020  popularization by co-author of two papers above
https://theconversation.com/arctic-sea-ice-is-being-increasingly-melted-from-below-by-warming-atlantic-water-144106

"What’s causing this decline in minimum sea ice extent? The short answer is our changing climate. But the more specific answer is that Arctic sea ice is increasingly being thinned not just by warm air from above but by ever-warmer waters from below.

In fact, in a recently published scientific study my colleagues and I looked at why sea ice was melting in the eastern Arctic Ocean and showed that the influence of heat from the interior of the ocean has now overtaken the influence of the atmosphere.

While atmospheric heat is the dominant reason for melting in the summer, it has little influence during the cold dark polar winter. However, the ocean warms the ice from below year-round. Our new research shows that this influence has more than doubled over the past decade or so and is now equivalent to the melting of nearly a meter thickness of sea ice each year.

Further to the east, this warm water has been isolated from the sea surface and so sea ice by a layer of colder, fresher water. However, as the heat blob is getting warmer and moving closer to the surface its influence is now spreading eastwards through the Arctic.

In a second scientific paper we showed that currents in the upper Arctic ocean were increasing, which when combined with declining sea ice and the weakening of the boundaries between layers of warm and cold water, was potentially stirring more warm water from the heat blob towards the surface. The combined impact is a new back and forth relationship between sea ice and ocean heat which could lead to a new ocean climate state in the eastern Arctic Ocean."
Title: Re: The 2020/2021 freezing season
Post by: uniquorn on October 13, 2020, 11:31:10 PM
It's time to go to night vision using worldview terra modis viirs brightness temperature band 15 (night or day) https://go.nasa.gov/2FpoLVd
Today's image showing the effect of wind driven drift on the Atlantic front (awi amsr2 v103 from yesterday inset)

Quote
The VIIRS Brightness Temperature, Band I5 Night layer is the brightness temperature, measured in Kelvin (K), calculated from the top-of-the-atmosphere radiances. It does not provide an accurate temperature of either clouds nor the land surface, but it does show relative temperature differences which can be used to distinguish features both in clouds and over clear land. It can be used to distinguish land, sea ice, and open water over the polar regions during winter (in cloudless areas).

The VIIRS Brightness Temperature layer is calculated from VIIRS Calibrated Radiances (VNP02) and is available from the joint NASA/NOAA Suomi National Polar orbiting Partnership (Suomi NPP) satellite. The sensor resolution is 375m, the imagery resolution is 250m, and the temporal resolution is daily.

Only one Polarview (https://www.polarview.aq/arctic) S1B of the area today.

It's also worth looking at relatively cloud free sea ice north of the CAA today. High winds are forecast for this area too over the next couple of days.      https://go.nasa.gov/3dAMzSN
Title: Re: The 2020/2021 freezing season
Post by: FishOutofWater on October 14, 2020, 12:18:53 AM
The ECMWF forecasts that ice will thicken rapidly on the Canadian side of the central Arctic when the high pressure sets up there. However, the strong winds over the warm waters on the Siberian side will enhance Fram export and reduce ice edge growth. Moreover, skies are likely to be cloudy and possibly stormy on the Siberian side of the pole because the ice edge will be a baroclinic zone and warm water quickly produces clouds when nights get cold.

https://www.ecmwf.int/en/forecasts/charts/catalogue/medium-snow-sic?facets=undefined&time=2020101300,228,2020102212&projection=classical_arctic
Title: Re: The 2020/2021 freezing season
Post by: A-Team on October 14, 2020, 12:59:44 AM
Quote
the ice edge is a baroclinic zone --> clouds --> heat retained
Right. Here's a very nice display of historic October extent on the Siberian side that really brings out the unprecedented situation of the current season. The trend is to open earlier, open more, freeze later in this region of the Arctic Ocean.

Yet another fabulous graphic from @zlabe ... such an effective color scheme! Needs an inset map that defines 'Siberian Arctic' though. See above for closely related nice graphic from Geronto.)
Title: Re: The 2020/2021 freezing season
Post by: Aluminium on October 14, 2020, 06:10:39 AM
October 9-13.

2019 (https://forum.arctic-sea-ice.net/index.php/topic,2888.msg233131.html#msg233131).
Title: Re: The 2020/2021 freezing season
Post by: Positive retroaction on October 14, 2020, 09:57:37 AM
Quote
the ice edge is a baroclinic zone --> clouds --> heat retained
Right. Here's a very nice display of historic October extent on the Siberian side that really brings out the unprecedented situation of the current season. The trend is to open earlier, open more, freeze later in this region of the Arctic Ocean.

Yet another fabulous graphic from @zlabe ... such an effective color scheme! Needs an inset map that defines 'Siberian Arctic' though. See above for closely related nice graphic from Geronto.)
Yes, thanks for this excellent représentation
If I understand correctly, from now on and for 2 weeks, we arrive in the zone of strong growth of 2012, and of average maximum increase of the other years as well. what will happen in 2020 during these 2 weeks is likely to be really interesting to follow, will the increase simply be delayed (which is already significant), or will it also be reduced because of the strong temperature anomalies?
the sea between the central pack and the ice of the shallower coasts ( that will freeze very late) will probable freeze, but maybe exceptionally late to be very thin at the start of the melt season, as you say in previous posts
Title: Re: The 2020/2021 freezing season
Post by: BornFromTheVoid on October 14, 2020, 10:57:40 AM
Animation, 8th to 13th.
Title: Re: The 2020/2021 freezing season
Post by: Freegrass on October 14, 2020, 01:17:35 PM
Latest Five Day Forecast
Wind @ Surface + Total Precipitable Water
Wind + Temp @ 850hPa
Large GiFS!
Title: Re: The 2020/2021 freezing season
Post by: grixm on October 14, 2020, 01:34:47 PM
Definitely some more refreeze outside the Lena delta.
Title: Re: The 2020/2021 freezing season
Post by: uniquorn on October 14, 2020, 03:29:34 PM
Definitely some more refreeze outside the Lena delta.
Yes. Today may be the last day to check using corrected reflectance. Sea temperatures 50km from the coast were still just a touch cooler than the Lena river. Low cloud and fog a bit cooler.
Rainbow1 palette on viirs brightness temperature.
https://go.nasa.gov/374tZkp
Title: Re: The 2020/2021 freezing season
Post by: RoxTheGeologist on October 14, 2020, 06:19:10 PM

.....

An immense volume of warm water is still several degrees above the freezing point of salt water from the surface to a depth of 30+m, again out to Oct 22nd, making for some 90,000 cubic km of sea water needing to be cooled (if vertically mixed) by air having only a thousandth the specific heat capacity.

....


... And air with increased humidity to reduce emissions to space.
Title: Re: The 2020/2021 freezing season
Post by: Général de GuerreLasse on October 14, 2020, 09:18:46 PM
Quote
No idea, I’d say it’s too cold
I would say it's far too warm between the ice pack and the entire Siberian side to even be considering refreezing inroads by Nov 1st. The southern limit of ice has hardly budged since Oct 1st (magenta line) so still has 1200 km to go. The sea surface temperature anomalies are remarkable today and even out nine days to Oct 22nd, per Mercator Ocean.

An immense volume of warm water is still several degrees above the freezing point of salt water from the surface to a depth of 30+m, again out to Oct 22nd, making for some 90,000 cubic km of sea water needing to be cooled (if vertically mixed) by air having only a thousandth the specific heat capacity.

A delayed freeze has significant consequences in terms of thinner, brine pockety ice by spring like it did last year in the wake of the extreme TransPolar Drift

The Chukchi is even slated to get warmer towards the end of the month from incoming advection of yet warmer waters from the Bering Sea. At this rate, the southern Chukchi will remain open water into early or even mid January.

Weakening of Cold Halocline Layer Exposes Sea Ice to Oceanic Heat in the Eastern Arctic Ocean
IV Polyakov, T Rippeth et al
J. Climate (2020) 33 (18): 8107–8123.
https://journals.ametsoc.org/jcli/article/33/18/8107/353233 free full

"The upward release of AW heat is regulated by the stability of the overlying halocline, which we show has weakened substantially in recent years. Shoaling of the AW has also contributed, with observations in winter 2017–18 showing AW at only 80 m depth, just below the wintertime surface mixed layer, the shallowest in our mooring records. The weakening of the halocline for several months at this time implies that AW heat was linked to winter convection associated with brine rejection during sea ice formation. This resulted in a substantial increase of upward oceanic heat flux during the winter season, from an average of 3–4 W m−2 in 2007–08 to >10 W m−2 in 2016–18. This seasonal AW heat loss in the eastern EB is equivalent to a more than a twofold reduction of winter ice growth. These changes imply a positive feedback as reduced sea ice cover permits increased mixing, augmenting the summer-dominated ice-albedo feedback."

Greater role for Atlantic inflows on sea-ice loss in the Eurasian Basin of the Arctic Ocean
IV Polyakov et al
Science  21 Apr 2017
https://science.sciencemag.org/content/356/6335/285.full  free full

Arctic sea ice is being increasingly melted from below by warming Atlantic water
Tom Rippeth  Prof Physical Oceanography, Bangor ME
September 18, 2020  popularization by co-author of two papers above
https://theconversation.com/arctic-sea-ice-is-being-increasingly-melted-from-below-by-warming-atlantic-water-144106

"What’s causing this decline in minimum sea ice extent? The short answer is our changing climate. But the more specific answer is that Arctic sea ice is increasingly being thinned not just by warm air from above but by ever-warmer waters from below.

In fact, in a recently published scientific study my colleagues and I looked at why sea ice was melting in the eastern Arctic Ocean and showed that the influence of heat from the interior of the ocean has now overtaken the influence of the atmosphere.

While atmospheric heat is the dominant reason for melting in the summer, it has little influence during the cold dark polar winter. However, the ocean warms the ice from below year-round. Our new research shows that this influence has more than doubled over the past decade or so and is now equivalent to the melting of nearly a meter thickness of sea ice each year.

Further to the east, this warm water has been isolated from the sea surface and so sea ice by a layer of colder, fresher water. However, as the heat blob is getting warmer and moving closer to the surface its influence is now spreading eastwards through the Arctic.

In a second scientific paper we showed that currents in the upper Arctic ocean were increasing, which when combined with declining sea ice and the weakening of the boundaries between layers of warm and cold water, was potentially stirring more warm water from the heat blob towards the surface. The combined impact is a new back and forth relationship between sea ice and ocean heat which could lead to a new ocean climate state in the eastern Arctic Ocean."

Hi A-Team, I have two questions.

Concerning the first image, the temperature anomalies are compared to what average?

I also have the impression to see through the pack ice areas of warmer sea water below the geographical North Pole, illusion of my old eyes or reality?

Thank you for your precious posts.
Title: Re: The 2020/2021 freezing season
Post by: Aluminium on October 15, 2020, 08:31:42 AM
A large red field of wind is forecasted in the Arctic.
Title: Re: The 2020/2021 freezing season
Post by: aslan on October 15, 2020, 09:09:55 AM
On top of all the retroaction already described, there is also the fact that an open ocean generate less friction, and the lack of an inversion increase even more the wind speed at surface. This is visible for the storm of Friday and Saturday. The low level jet brings stronger winds at surface over open ocean than sea ice. The cross section is from south to north, trough the low level jet for Saturday at 12Z. Higher wind speed reached the surface open ocean.

P.S. ; One important point... For the map, it is wind speed at 500m, not surface. There is two LLJs, one over sea ice and one over open ocean, but strong winds at 10m are only found over open ocean.
Title: Re: The 2020/2021 freezing season
Post by: El Cid on October 15, 2020, 09:49:06 AM
But wouldn't stronger winds vent more heat out of the Arctic and therefore speed up refreeze? I mean, with stronger winds, heat exchange should be faster, the water should cool down faster and ice should appear faster as well. So isn't it a positive feedback, meaning that big open seas lead to faster refreeze due to stronger winds?
Title: Re: The 2020/2021 freezing season
Post by: aslan on October 15, 2020, 09:57:15 AM
This means a stronger broclinic zone, with more clouds and moisture keeping the Arctic warm, and it means a weaker halocline with more mixing and shoaling of the Atlantic waters. By the way, even though the anomalies of temperatures are less extreme, the islands of the russian arctic are still running for the hottest month of October in record from the Barents to the East Siberian sea :

http://www.pogodaiklimat.ru/monitor.php?id=20069

http://www.pogodaiklimat.ru/monitor.php?id=21432
Title: Re: The 2020/2021 freezing season
Post by: binntho on October 15, 2020, 10:07:24 AM
This is the second mentioning of "shoaling" in recent days, see also A-Teams post above:

Weakening of Cold Halocline Layer Exposes Sea Ice to Oceanic Heat in the Eastern Arctic Ocean
IV Polyakov, T Rippeth et al
J. Climate (2020) 33 (18): 8107–8123.
https://journals.ametsoc.org/jcli/article/33/18/8107/353233 free full

"The upward release of AW heat is regulated by the stability of the overlying halocline, which we show has weakened substantially in recent years. Shoaling of the AW has also contributed ...

I understand shoaling to mean what happens to waves as the approach shallower water (shoals) . According to Wikipedia shoaling happens when depth is less than half the wavelength.

Other meanings are "becoming shallower" and also when aquatic organisms group together (e.g. a shoal of herring).

So how does that fint into the bigger picture of an open ocean as Aslan seems to talk about, and what is meant by a phrase like "shoaling of the Atlantic Waters" as in the paper quoted by A-Team?
Title: Re: The 2020/2021 freezing season
Post by: aslan on October 15, 2020, 10:50:59 AM
This is the second mentioning of "shoaling" in recent days, see also A-Teams post above:

Weakening of Cold Halocline Layer Exposes Sea Ice to Oceanic Heat in the Eastern Arctic Ocean
IV Polyakov, T Rippeth et al
J. Climate (2020) 33 (18): 8107–8123.
https://journals.ametsoc.org/jcli/article/33/18/8107/353233 free full

"The upward release of AW heat is regulated by the stability of the overlying halocline, which we show has weakened substantially in recent years. Shoaling of the AW has also contributed ...

I understand shoaling to mean what happens to waves as the approach shallower water (shoals) . According to Wikipedia shoaling happens when depth is less than half the wavelength.

Other meanings are "becoming shallower" and also when aquatic organisms group together (e.g. a shoal of herring).

So how does that fint into the bigger picture of an open ocean as Aslan seems to talk about, and what is meant by a phrase like "shoaling of the Atlantic Waters" as in the paper quoted by A-Team?

Err I am not really good at speaking english. AW are below the halocline. With waves, mixing weakens the halocline and allow heat transfer from the AW. For me shoaling means that AW are "less deep" and nearer to surface, with increased heat flux.

For the baroclinicity, I have added the vorticity (blue, positive, and red negative) and T'w in black. We can see that near the surface, the strong inversion is associated with the gradient in wind speed. This also creates shear and then vorticity. We have, as usual, shear zone and vorticity to the left and right to the LLJ, but near the surface there is also vorticity associated with the shear zone at the interface between sea ice and open ocean. But the max of vorticity over sea ice in the lowest 500 meters is really linked to the interface between sea ice and open ocean, it is not linked to the shear due to the deceleration of wind speed.
Title: Re: The 2020/2021 freezing season
Post by: binntho on October 15, 2020, 11:06:17 AM
[ AW are below the halocline. With waves, mixing weakens the halocline and allow heat transfer from the AW. For me shoaling means that AW are "less deep" and nearer to surface, with increased heat flux.

I think you are right, and this is probably what they meant in the article that A-Team linked to as well. And as such it is a proper if perhaps not common use of the word "shoaling".

Other than that I enjoy your postings, they are verey educational and gives a different view of the strangeness that is the modern Arctic.
Title: Re: The 2020/2021 freezing season
Post by: A-Team on October 15, 2020, 12:51:57 PM
Quote
sea surface anomalies relative to what baseline years? How is SST measured under the ice pack?
There are a lot of mysteries associated with polar data displayed on the flashy Mercator Ocean portal. Sparse and infrequent observational input from moorings might constrain the model but satellite data is limited to surface parameters such as waves, currents, wind, salinity and temperature. It's not clear that these (and Archimedean considerations) suffice to model conditions at depth or under the ice pack.

The impossible underwater detail shown say for Bering Strait inflows -- can it be more than an ensemble run for illustrative purposes? Here it must be said that oceanography is a whole lot slower moving than weather. Thus salinity at 3000m in the Makorov Basin might change but on a century or even millennial basis, not daily like air pressure. Once known though, it constrains the rest of the model.

The baseline years for SST aren't provided but are presumably conventional (though who and how was it measured daily?). In terms of the relative anomaly of Oct 2020 SST, Mercator only offers Oct 2019 which was a lot less: http://bulletin.mercator-ocean.fr/en/PSY4#3/65.95/-72.51

Other quantities go back a few years farther and are provided at various depths. The SST anomaly is only provided for the surface. The Leaflet tool does not couple palette to image colors (like AMSR2_AWI) making it difficult to do more than estimate anomaly values.

There's a very elaborate new GIS layer tool called CMEMS that's only received scant attention on the forums. It has quite a few SST products and better descriptions. The layers are still supplied by Mercator Ocean though the Lobelia Earth viewer is an amazing development.

"Arctic Sea and Ice surface temperature product based upon observations from the Metop_A AVHRR instrument. The product is a daily interpolated field with a 0.05 degrees resolution, and covers surface temperatures in the ocean, the sea ice and the marginal ice zone. Temporal extent… 7 July 2018 to now."

https://cmems.lobelia.earth/data?view=viewer&crs=epsg%3A3408
Quote
shoaling?
Shoaling is a old nautical term; shoals like those off NE Greenland are shallows where a ship could run aground; thus a shoaling course (rapidly decreasing depth to the bottom) is concerning. In oceanography, it just means a water mass of interest is getting closer to the surface. 

The Gulf Stream core depth in the Fram off Svalbard is about 300m, too deep to affect the ice above given the density stratification keeping AW in its place until the Yermak. Various mixing processes described in Polyakov 2020 are now causing Atlantic Water heat to rise closer to the surface, not just north of the SV-FJL-SZ line but progressing beyond to the Laptev shelf during the 15 years of the shelf transect mooring data.

There's always been enough incoming heat to melt all the ice, the issue has been meager re-distribution by double diffusion staircases prior to export back out the Fram. However the downward trend in sea ice has brought a change-over from atmospheric to marine dominance of the energy balance.

As the buoyancy gradient (thermohalocline) begins dissipating from more shear and turbulence attributable to more open water resulting from sea ice decline, the heat brought nearer to the surface just leads to more sea ice decline, a runaway positive feedback that the authors see as immune to climate change mitigation efforts. As with Pine Island and Thwaites ice sheets in Antarctica and marine terminating glaciers in west Greenland, once change is marine-driven, it's much harder to affect outcome.
Title: Re: The 2020/2021 freezing season
Post by: BornFromTheVoid on October 15, 2020, 01:59:43 PM
The pressure gradients this weekend looks like producing some significant waves from the Chukchi through to the Laptev sea, often over 5 m. The effect this has on the halocline and newly formed ice should be interesting.
Data from the ECMWF

Title: Re: The 2020/2021 freezing season
Post by: Freegrass on October 15, 2020, 02:20:40 PM
Latest Five Day Forecast
Wind + Temp @ Surface
Large GiF!

I don't understand why only 11 people looked at the precipitable water video from yesterday...  ???

Yes, it's windy, and the ocean will get a big stir, with more harm to the halocline I presume? But I understand now that moisture is the most potent greenhouse gas on earth, that besides bringing in heat from southern latitudes, it's also preventing the Arctic ocean from releasing heat...

It's like a pre-heated blanket covering an Arctic fever, and nobody is looking at it?  :o

When a High Pressure System can't cool down the Arctic after equinox, that's messed up, isn't it?
Title: Re: The 2020/2021 freezing season
Post by: gandul on October 15, 2020, 02:21:54 PM
...
There's always been enough incoming heat to melt all the ice, the issue has been meager re-distribution by double diffusion staircases prior to export back out the Fram. However the downward trend in sea ice has brought a change-over from atmospheric to marine dominance of the energy balance.

As the buoyancy gradient (thermohalocline) begins dissipating from more shear and turbulence attributable to more open water resulting from sea ice decline, the heat brought nearer to the surface just leads to more sea ice decline, a runaway positive feedback that the authors see as immune to climate change mitigation efforts.

Not sure how that works.

Let's take this weekend as example. Strong winds are going to pull some (or a lot) of heat excess to the open ocean surface, which is continuously going to be released to the atmosphere (much colder than the ocean surface) and to the space. It is not going to lead to more sea ice decline, since in the following days darkness is an almost infinite sink of heat excess until next Spring. So this weekend is going to lead to less heat stored beneath.

Where in the preceding paragraph am I wrong?
Title: Re: The 2020/2021 freezing season
Post by: binntho on October 15, 2020, 02:49:56 PM
Let's take this weekend as example. Strong winds are going to pull some (or a lot) of heat excess to the open ocean surface, which is continuously going to be released to the atmosphere (much colder than the ocean surface) and to the space.

Isn't this exactly what Arctic Amplification is about? The heat is transferred from the ocean to the atmosphere, raising air temperatures and delaying refreeze. The atmosphere nearest the surface rapidly warms while the surface cools. But if heat is constantly being brought up from below, and the air is constantly pulling this heat out and distributing it in the atmosphere, then atmospheric temperatures will rise.

This will delay refreeze significantly I should think. The only question is how long this excess heat stays in the atmosphere before radiating out to space. That is perhaps the most important part of the equation: The heat that is released from the ocean this weekend, will some of it still be lingering next week or next month or will it all disappear out into space within a few hours?
Title: Re: The 2020/2021 freezing season
Post by: Freegrass on October 15, 2020, 02:59:09 PM
Let's take this weekend as example. Strong winds are going to pull some (or a lot) of heat excess to the open ocean surface, which is continuously going to be released to the atmosphere (much colder than the ocean surface) and to the space.

Isn't this exactly what Arctic Amplification is about? The heat is transferred from the ocean to the atmosphere, raising air temperatures and delaying refreeze. The atmosphere nearest the surface rapidly warms while the surface cools. But if heat is constantly being brought up from below, and the air is constantly pulling this heat out and distributing it in the atmosphere, then atmospheric temperatures will rise.

This will delay refreeze significantly I should think. The only question is how long this excess heat stays in the atmosphere before radiating out to space. That is perhaps the most important part of the equation: The heat that is released from the ocean this weekend, will some of it still be lingering next week or next month or will it all disappear out into space within a few hours?
I guess a huge part of that heat will rain back down on earth? And if not rain, snow, which will insulate?
Title: Re: The 2020/2021 freezing season
Post by: SimonF92 on October 15, 2020, 03:36:44 PM
Let's take this weekend as example. Strong winds are going to pull some (or a lot) of heat excess to the open ocean surface, which is continuously going to be released to the atmosphere (much colder than the ocean surface) and to the space.

Isn't this exactly what Arctic Amplification is about? The heat is transferred from the ocean to the atmosphere, raising air temperatures and delaying refreeze. The atmosphere nearest the surface rapidly warms while the surface cools. But if heat is constantly being brought up from below, and the air is constantly pulling this heat out and distributing it in the atmosphere, then atmospheric temperatures will rise.

This will delay refreeze significantly I should think. The only question is how long this excess heat stays in the atmosphere before radiating out to space. That is perhaps the most important part of the equation: The heat that is released from the ocean this weekend, will some of it still be lingering next week or next month or will it all disappear out into space within a few hours?
I guess a huge part of that heat will rain back down on earth? And if not rain, snow, which will insulate?

Id go as far as to suggest its inevitable that Siberia will have anomalously high snow-mass-balance this Autumn/Winter given that large amounts of open Arctic water will increase precipitation. The prevailing wind pattern this week is toward the continent. You can see the Siberian Islands already have positive anomalies of +100cm snow depth.

There are some forum members who would argue that once a certain depth is reached, this snowfall would be protective in the following summer and would help to prevent a blowtorch in June. Personally, im not convinced we will ever see this effect.
Title: Re: The 2020/2021 freezing season
Post by: aslan on October 15, 2020, 03:41:17 PM
...
There's always been enough incoming heat to melt all the ice, the issue has been meager re-distribution by double diffusion staircases prior to export back out the Fram. However the downward trend in sea ice has brought a change-over from atmospheric to marine dominance of the energy balance.

As the buoyancy gradient (thermohalocline) begins dissipating from more shear and turbulence attributable to more open water resulting from sea ice decline, the heat brought nearer to the surface just leads to more sea ice decline, a runaway positive feedback that the authors see as immune to climate change mitigation efforts.

Not sure how that works.

Let's take this weekend as example. Strong winds are going to pull some (or a lot) of heat excess to the open ocean surface, which is continuously going to be released to the atmosphere (much colder than the ocean surface) and to the space. It is not going to lead to more sea ice decline, since in the following days darkness is an almost infinite sink of heat excess until next Spring. So this weekend is going to lead to less heat stored beneath.

Where in the preceding paragraph am I wrong?

The Arctic in winter is not an infinite heat sink. Definitively NOT. There is a thing names moisture and another names cloud which is in play,

http://ogimet.com/cgi-bin/gsynres?ind=20069&decoded=yes&ndays=50&ano=2020&mes=10&day=15&hora=12

and there is also the fact that heat builds up in summmer in Arctic, and the heat transported from the tropics - a region where the bilan is strongly positive - etc. Arctic in winter is not an infinite heat sink. And never was one by the way. It is not a proof, but just look at the correlation between Nh and T at Ostrov Vize here for example :

http://ogimet.com/cgi-bin/gsynres?ind=20069&decoded=yes&ndays=50&ano=2012&mes=1&day=15&hora=12
Title: Re: The 2020/2021 freezing season
Post by: Freegrass on October 15, 2020, 03:54:39 PM
Let's take this weekend as example. Strong winds are going to pull some (or a lot) of heat excess to the open ocean surface, which is continuously going to be released to the atmosphere (much colder than the ocean surface) and to the space.

Isn't this exactly what Arctic Amplification is about? The heat is transferred from the ocean to the atmosphere, raising air temperatures and delaying refreeze. The atmosphere nearest the surface rapidly warms while the surface cools. But if heat is constantly being brought up from below, and the air is constantly pulling this heat out and distributing it in the atmosphere, then atmospheric temperatures will rise.

This will delay refreeze significantly I should think. The only question is how long this excess heat stays in the atmosphere before radiating out to space. That is perhaps the most important part of the equation: The heat that is released from the ocean this weekend, will some of it still be lingering next week or next month or will it all disappear out into space within a few hours?
I guess a huge part of that heat will rain back down on earth? And if not rain, snow, which will insulate?

Id go as far as to suggest its inevitable that Siberia will have anomalously high snow-mass-balance this Autumn/Winter given that large amounts of open Arctic water will increase precipitation. The prevailing wind pattern this week is toward the continent. You can see the Siberian Islands already have positive anomalies of +100cm snow depth.

There are some forum members who would argue that once a certain depth is reached, this snowfall would be protective in the following summer and would help to prevent a blowtorch in June. Personally, im not convinced we will ever see this effect.
My guess is that snow is easier to melt than ice? And wet snow - covered in "industrial and natural dirt" - decreases albedo?
And snow will prevent the giant Siberian ice cube (permafrost) from cooling down significantly?
Title: Re: The 2020/2021 freezing season
Post by: Sublime_Rime on October 15, 2020, 04:13:23 PM

Isn't this exactly what Arctic Amplification is about? The heat is transferred from the ocean to the atmosphere, raising air temperatures and delaying refreeze. The atmosphere nearest the surface rapidly warms while the surface cools. But if heat is constantly being brought up from below, and the air is constantly pulling this heat out and distributing it in the atmosphere, then atmospheric temperatures will rise.

This will delay refreeze significantly I should think. The only question is how long this excess heat stays in the atmosphere before radiating out to space. That is perhaps the most important part of the equation: The heat that is released from the ocean this weekend, will some of it still be lingering next week or next month or will it all disappear out into space within a few hours?

I think you allude to the crux of this question for me. which is how the massive amount of heat contained in the oceans is distributed. I think there are negative and positive feedback components of increased open water, but the overall effect is positive feedback...based on how the increased heat solar energy is distributed. One could argue there is a negative feedback from increased heat release from open water, and thereby less heat available for bottom melt. So the question seems to be: Is the heat and moisture release from open water more efficient at distributing heat to melt ice than if that heat remained in the sea water and contributed to bottom melt.

I think, considering that open water by definition is not interfacing efficiently with ice until it freezes, that the answer is yes. Also since open water increases potential for vertical mixing, the articles posted by A-team two days ago offer another means by which a positive feedback may exist (open water allowing deep Atlantic warmth to mix further up into contact with ice).
Title: Re: The 2020/2021 freezing season
Post by: A-Team on October 15, 2020, 05:25:40 PM
The 04 Aug 2020 article by Polyakov, Rippeth, Fer ... is an easy read, just skip over the data and methods sections; the first 3 authors have over 60 years of combined research experience on this very topic. It's not productive to speculate ab initio on your own without consideration of observational data and reviewed publications -- those are the point of departure.

https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2020GL089469 free full 2020
https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2001GL011111 free full 2002

The Copernicus CMEMS viewer by Lobelia Earth is really something. There's a learning curve but it's fast and stable. The pop-up even graphs the whole history of all the variable layers chosen! Hopefully more people here will look into this tool.

https://cmems.lobelia.earth/data?view=viewer&crs=epsg%3A3408

Below, the lobelia-earth graphic looks at an ice thickness cut-out over sea surface temperatures. Colors and contrast have been tweaked to bring out the main talking points namely (1) freeze-up, like melt, is largely a peripheral growth story (bright orange), (2) the Chukchi and north Svalbard are quite a bit warmer than the already too-warm Laptev and will be the last to freeze and (3) another 'Wrangel arm' is developing (faint orange) from the current lobe at 160-180º that will approach the ESS as the next major freezing season development.
Title: Re: The 2020/2021 freezing season
Post by: aslan on October 15, 2020, 05:41:55 PM
I think it is worth remembering we are living on Earth not Mars... We have a layer of gas above ours heads which is not transparent to IR. Even in the old, dark, dry Arctic of the past it was impossible to radiate an infinite amount of heat to space. There is always an upper limit. A temperature inversion in the low layer, even in Siberia in the 1880s could not have been greater to ~ -25°C. At some point, even in an absolutely dark and dry Arctic a point of equilibrium will be reached. And on top of that amount of heat lost to space is not primarily a function of the temperature at surface, it is not the case, definitively. The temperature at surface is not totally decorrelated from the heat lost to space of course. But there is an atmosphere above surface, in the end. It is Earth here, not Mars... Heat has to go trough the atmosphere before, and there is on the road CO2, CH4, H2O in every states possible, etc... And now that Arctic is providing a lot of heat and moisture, we are seeing a new state where there is a layer of clouds and moisture in the low layers which is isolating the surface, with temperature between 0 and -5°C at 2 meters versus -20°C to -30°C at 2 meters in the case there is no clouds.
Holy mother of Einstein, it is Earth here, not Mars !
The picture which follows is the forecast for Saturday for a given model. It is the minimum for the temperature of brilliance in infrared (10.8 microns) for the all day. Scale is from blue for the warmest (~0°C) to white (~ -40°C) going trough the brown / beige / I don't know which color (-10°C to -20°C). There is also the isolign for the surface temperature of -2°C to roughly approximate the edge of sea ice (more or less, we all see what the shape of sea ice currently). Over Beaufort, yes we are radiating at 0°C (blue color) and we are losing heat to space. But over Chukchi, ESS, Laptev, Kara, Barents, we have a layer of clouds as thick as the troposphere. And the temperature of brilliance is -20°C to -40°C. The temperature of brilliance is more directly correlated to heat lost to space than surface temperature. This really means, this really means, that during the storm, we are not going to radiate heat toward space at ~0°C from the ocean. We are going to radiate heat at -20°C or -30°C or -40°C. And there is a factor 1.5 to 2 between the radiation from a black body at 0°C and a black body at -30°C or something. The heat stirred by the storm is heat at ~0°C, the heat lost to space is heat at -30°C, and there is a ratio of 1.5 to 2 between the two... I made the same map but with the mean of the IR temperature from Friday to Thurday. The ice sheet is high and dry, radiating at -30°C and isolating the ocean at 0°C below. The Beaufort is, yes, a good heat sink fully radiating toward space. But for the siberian side, the clouds are here as the ice sheet, isolating the surface below. Even with a mean over 5 days, almost all the siberian side is forecasted to be isolated.
Title: Re: The 2020/2021 freezing season
Post by: Comradez on October 15, 2020, 07:24:37 PM
Thank you Aslan!  That is a very revealing graphic, and something worth keeping an eye on during the winter season.  It shows that the important thing, when judging whether open ocean in the winter is a positive or negative feedback, is the heat vented to space from the top of the atmospheric column, not the heat vented from the surface to slightly above the surface.  If the layer slightly above the surface is almost as opaque to IR as sea ice is, then that near-surface atmospheric layer basically functions like replacement sea ice—except it is "sea ice" that also lets the water column below it mix up warmer, saltier water to the surface, so double no-bueno there. 
Title: Re: The 2020/2021 freezing season
Post by: A-Team on October 15, 2020, 11:13:06 PM
Quote
Thank you Aslan!
Indeed Aslan has putting out some excellent corrective posts on net exchanges of energy via blackbody radiation (for ice: graybody emissivity) which goes on 24/7/365 ice cover or not.

Emissions are strictly proportional to the body's kelvin temperature to the fourth power (wiki: Stefan-Boltzmann) with the wavelength of maximal energy fading out inversely with temperature towards far infrared (wiki: Wien's displacement law). This era was the dawn of quantum mechanics with Planck having to invoke emission packet quantization in 1900 to resolve cavity unboundedness (wiki: ultraviolet catastrophe).

The amount of blackbody radiation emitted at 0ºC hardly differs from that at -1.8ºC being only 0.68% greater. The spectrum is very flattened but peaks at 2898 μm/kelvin temperature. A nice online tool for drawing the spectrum for any temperature and emissivity, along with energy per steradian, is at:

https://www.spectraplot.com/blackbody

Textbooks usually just show the sun's spectrum, a blackbody at 5778 K peaking at 0.501 μm in the green rather than say a mammal's blackbody emissions at 310K (wavelength in far infrared, 9.3 microns) or freezing sea water at 10.7 μm or freezing freshwater at 10.6.

The classical greenhouse effect arises from conversion of solar radiation, half of whose TOA energy lies below 0.710 μm, to heat that raises surface temperature and thus subsequent emissions at blackbody-appropriate longer wavelengths which are then adsorbed by greenhouse gases such as water vapor and CO2 that wouldn't have absorbed reflected visible so that solar is partially retained as atmospheric heat.

Arrhenius was already going on about this in 1896, with Fourier and Tyndall even earlier. Boltzmann equipartitioning had been established but not the molecular rotational and vibrational quanta accounting for (or missing in the crystalline state) the specifics of favored adsorptive/emissive wavelengths.

Blackbody radiation is by no means the only mechanism for cooling of Arctic open water and is not specific to it in the manner of evaporation, conduction and convection which are severely impeded by dry snow over thickening ice (wiki: heat equation). The overall energy flux has been studied for many decades at year-round ice camps and most recently by Mosaic.

The Arctic, one of the cloudiest places on earth, mainly has a low stratocumulus cloud cover which can be mixed phase (vapor, water droplets, snow crystals) adsorbing radiation from below and re-emitting it isotropically (ie sending 50% back down). [[Fixed typo noted by nanning below: means no preferred direction, all directions equally, so half up half down.]]

In fall and winter, this amounts to a seasonally delayed greenhouse effect with the Arctic often supplying its own self-limiting water vapor though moist intrusions from lower latitudes are also important. Microwave products such as Ascat can be adversely affected by this into even November and even later by major advective events.
Title: Re: The 2020/2021 freezing season
Post by: Cook on October 15, 2020, 11:17:00 PM
But wouldn't stronger winds vent more heat out of the Arctic and therefore speed up refreeze? I mean, with stronger winds, heat exchange should be faster, the water should cool down faster and ice should appear faster as well. So isn't it a positive feedback, meaning that big open seas lead to faster refreeze due to stronger winds?

How times change. I don't think anyone in the recent past would have imagined such a statement for the Arctic in October. An Arctic where there is heat to be vented out from. An Arctic where more wind and air transported from warmer regions is supposed to make it "cool down faster". An Arctic where big open seas are going to make things colder rather than warmer. I find these statements quite remarkable.

This time of year, due to lack of solar heating the Arctic is cooling as it loses heat outer space. Any winds/mixing from other regions will tend to warm it.

Just for the record, the Arctic is currently about +5C warmer than average, and that, folks is NOT a feedback that is somehow going to make things cool down and freeze "faster".

(https://i.postimg.cc/SKqhG05q/Temp-anomaly.jpg) (https://postimages.org/)
Title: Re: The 2020/2021 freezing season
Post by: josh-j on October 15, 2020, 11:25:15 PM
If the arctic is warm, of course it will radiate more heat than if it was cold and icy. But that isn't a good thing at all, its just physics  ;)

I'm not sure that observing more heat "venting to space" is as much of a feedback as it is just an observation of how hot the arctic is.

You don't look at a red hot pan you put on the stove without water inside and say, well at least there is a feedback in that it being hot means it is radiating heat away more. It certainly is doing so, but that doesn't mean it will reach room temperature faster than if you didn't heat it up in the first place.

Edit: removed broken household heating analogy :)
Title: Re: The 2020/2021 freezing season
Post by: Aluminium on October 16, 2020, 07:40:14 AM
October 11-15.

2019 (https://forum.arctic-sea-ice.net/index.php/topic,2888.msg233131.html#msg233131).
Title: Re: The 2020/2021 freezing season
Post by: nanning on October 16, 2020, 07:41:37 AM
Thanks for your high quality and informative posts!

A-Team wrote: "re-emitting it anisotropically" with text coloured blue.
I'm sorry, I try to understand these posts and this maybe a stupid question, but shouldn't that be "re-emitting it isotropically"?
Title: Re: The 2020/2021 freezing season
Post by: jdallen on October 16, 2020, 07:50:35 AM
<snip>
The Copernicus CMEMS viewer by Lobelia Earth is really something. There's a learning curve but it's fast and stable. The pop-up even graphs the whole history of all the variable layers chosen! Hopefully more people here will look into this tool.

https://cmems.lobelia.earth/data?view=viewer&crs=epsg%3A3408
<snip>
I agree... just started playing with it and already impressed.
Title: Re: The 2020/2021 freezing season
Post by: El Cid on October 16, 2020, 07:53:41 AM
Ok, just for the record, there was some talk upthread about stronger than usual winds in the Arctic. I asked about whether these winds should cool down the Arctic faster. It may be a stupid question, but when I have a hot cup of tea and blow it continuously, it cools down faster than if it stays calm.
But maybe the Arctic ain't my cup of tea...
Title: Re: The 2020/2021 freezing season
Post by: binntho on October 16, 2020, 07:58:08 AM
It's not productive to speculate ab initio on your own without consideration of observational data and reviewed publications -- those are the point of departure.

https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2020GL089469 free full 2020
https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2001GL011111 free full 2002

Being properly chastened, I hastened to read the two publications. The first one is very good, and totally on topic for our discussion. The second one left me scratching my head in amazement.

To begin with, the article is 20 years old and thus out of date given the subject matter. But the purpose of the arcticle is to show that there is no polar amplification. It does that by using a fairly common denier trope of claiming that multidecadal oscillations are confusing the signal, and once these are taken into account, the authors seem to be claiming to show that the arctic air temperatures have not incrased faster than global temperatures. Hence no "global warming arctic amplification"!

My conclusion (which may of course be totally wrong) is that this is an outdated article with erroneus conclusions, and I fail to see what it has to do with our discussions or the ongoing changes in the Arctic.
Title: Re: The 2020/2021 freezing season
Post by: binntho on October 16, 2020, 08:00:19 AM
Ok, just for the record, there was some talk upthread about stronger than usual winds in the Arctic. I asked about whether these winds should cool down the Arctic faster. It may be a stupid question, but when I have a hot cup of tea and blow it continuously, it cools down faster than if it stays calm.
But maybe the Arctic ain't my cup of tea...

Your room does not cool down when you blow across a cup of tea.
Title: Re: The 2020/2021 freezing season
Post by: grixm on October 16, 2020, 08:43:26 AM
Ok, just for the record, there was some talk upthread about stronger than usual winds in the Arctic. I asked about whether these winds should cool down the Arctic faster. It may be a stupid question, but when I have a hot cup of tea and blow it continuously, it cools down faster than if it stays calm.
But maybe the Arctic ain't my cup of tea...

Your room does not cool down when you blow across a cup of tea.

But the cup does. And the cup here is the ocean where the ice can form.
Title: Re: The 2020/2021 freezing season
Post by: El Cid on October 16, 2020, 08:58:41 AM
Ok, just for the record, there was some talk upthread about stronger than usual winds in the Arctic. I asked about whether these winds should cool down the Arctic faster. It may be a stupid question, but when I have a hot cup of tea and blow it continuously, it cools down faster than if it stays calm.
But maybe the Arctic ain't my cup of tea...

Your room does not cool down when you blow across a cup of tea.

I asked about the tea (ice forming) not the room (global temps) not even the cup

Never mind
Title: Re: The 2020/2021 freezing season
Post by: binntho on October 16, 2020, 09:28:12 AM
You ask about "the Arctic" and then concentrate solely on the surface of the ocean. Which is a fallacy. When heat escapes the sufarce on the ocean it raises air temperatures, but the heat is still in the Arctic. And since the ocean will only freeze if air temperatures are low enough, any process that raises air temperatures is going to delay refreeze.

The cup comparison repeats the same fallacy - the air that flows over the surface of the cup is a lot hotter than the surrounding air, and if we take the cup to be the open waters of the Arctic, then the surroundings of the cup are the rest of the Arctic. And blowing across the surface of the cup is going to warm up the surroundings faster than not blowing across the surface of the cup.
Title: Re: The 2020/2021 freezing season
Post by: Oyvind Johnsen on October 16, 2020, 09:49:46 AM
Ok, just for the record, there was some talk upthread about stronger than usual winds in the Arctic. I asked about whether these winds should cool down the Arctic faster. It may be a stupid question, but when I have a hot cup of tea and blow it continuously, it cools down faster than if it stays calm.
But maybe the Arctic ain't my cup of tea...

The air you blow out is colder than the air just above the tea. Blowing the tea will increase the temperature difference between the tea surface and the air above it, and thereby increase heat loss. Whereas winds blowing into the Arctic in general will be warmer than the air above the sea, causing the opposite effect.
Title: Re: The 2020/2021 freezing season
Post by: El Cid on October 16, 2020, 10:38:41 AM
OK, so asking whether current strong winds will lead to faster or slower ice formation (=freezing) in the Arctic is a fallacy. Yeah, whatever.
Though this was the freezing season thread last time I checked.

There could have been many possible answers, like:

- wind speed does not have a major effect on ice formation or
- wind speed has this and this effect on ice formation or
- it depends, in this case this happens in that that happens or
- we do not know

I mean, I don't understand the hostility. It is a highly relevant question for this freezing season and noone has yet written anything relevant other than bugger off.

But oren will stop me now I know, so end of rant
Title: Re: The 2020/2021 freezing season
Post by: binntho on October 16, 2020, 11:06:26 AM
It seems to me that lots of people have been trying to answer this or similar questions. And the general consensus seems to be "no", or "perhaps", or "not sure". But not "yes" as far as I can see.

The wind is part of the Arctic, and when the wind blows faster over warm waters, the wind warms up faster and the waters cool down faster. Does that speed up or slow down refreeze?

The process of freezing sea water requires very cold air, and any process that warms up the air is going to slow down refreeze. Strong winds over open waters warms the air, quicker, hence slows down refreeze even more ... or mabye not?

The fallacy was when you compared strong winds in the Arctic with blowing air over a cup of tea. The winds are part of the Arctic, but the air over the cup is not part of the cup. It is thus a false comparison.
Title: Re: The 2020/2021 freezing season
Post by: SimonF92 on October 16, 2020, 11:09:08 AM
One could argue that the wind over the ESS right now is not part of the Arctic
Title: Re: The 2020/2021 freezing season
Post by: binntho on October 16, 2020, 11:17:27 AM
And the ocean is of course not part of the Arctic eather, with the waters constantly flowing from one part of the world to another.
Title: Re: The 2020/2021 freezing season
Post by: SimonF92 on October 16, 2020, 11:24:43 AM
And the ocean is of course not part of the Arctic eather, with the waters constantly flowing from one part of the world to another.

I agree with your point binntho- about the cup being a part of the room
Title: Re: The 2020/2021 freezing season
Post by: oren on October 16, 2020, 11:28:17 AM
Folks, please don't get tied up in knots.
El Cid, I thought yours was a good question. However, it seems the analogy doesn't work so well because the ocean is not much warmer than the wind, and because the ocean is deep. OTOH yes, the wind will help mix and cool the deeper layers and eventually achieve refreeze. But when the wind is warmer than the ocean, well I guess the opposite is true. Of course, all this would not have happened if the ocean was not abmormally warm, so nothing here to be happy about.
Other folks, please treat questions nicely and please make your answers to the point, especially avoiding sarcasm.
In general I find it best to avoid analogies from everyday life as they often don't fit what goes on in the Arctic.
Title: Re: The 2020/2021 freezing season
Post by: so_whats_happening on October 16, 2020, 02:06:12 PM
Hey folks first time poster in any refreezing thread just figured I would try to better understand what is going on in the arctic, not my strong suit but trying to branch out and understand the different components in the Earth System.

So first and foremost these will all be arbitrary numbers no factual numbers.

Starting off we have open waters with a temperature of 5C in the surface layer of the ocean. We have a wind system coming in causing mixing to decent depths as one would expect in an open ocean. With this, say 20-30mph, wind across open waters that are warmer one would think on a normal basis that this would cause cooling, which it does for the ocean waters in this case. So now we have cooled the ocean waters from 5 to 3C that heat just doesn't escape as many have noted it goes into the surrounding environment. The heat from the ocean also plays its role even though some of that heat is loss it still warms the environment so it acts sort of like a double whammy in that sense. So now instead of having an atmosphere that was fairly close to freezing say around -5C the combined heat bring this closer to 0C if not potentially warmer. Now if the winds persist the idea is that this released heat from not only the ocean but from the winds cooling the ocean wont just sit over one area it spreads throughout the arctic and even potentially onto land depending on distance and location of the event.

Is it the leftover moisture in the atmosphere causing the issue and concern for the lack of refreezing because in order to remove that moisture it must precipitate which in turn causes clouds and further warming the surrounding atmosphere? I know snow insulates so the blanket then potentially doesn't allow proper refreezing to occur which in turn doesn't allow for cooler temps to form?

Maybe I need a little guidance better into that understanding, but I also believed removal of heat from the ocean was a good thing especially if wind patterns kept up to advect this from just staying in the same place. Moisture is a blessing and curse at the same time.

Please don't scrutinize me to harshly
Title: Re: The 2020/2021 freezing season
Post by: psymmo7 on October 16, 2020, 02:06:40 PM
Well moderated Oren!
Title: Re: The 2020/2021 freezing season
Post by: oren on October 16, 2020, 02:28:06 PM
Welcome, s_w_h. The first post is the hardest.
Title: Re: The 2020/2021 freezing season
Post by: Shared Humanity on October 16, 2020, 02:49:23 PM


I mean, I don't understand the hostility. It is a highly relevant question for this freezing season and noone has yet written anything relevant other than bugger off.


You asked a relevant question but I see very little hostility in the responses, simply persons disagreeing with you.
Title: Re: The 2020/2021 freezing season
Post by: The Walrus on October 16, 2020, 03:29:36 PM
You ask about "the Arctic" and then concentrate solely on the surface of the ocean. Which is a fallacy. When heat escapes the sufarce on the ocean it raises air temperatures, but the heat is still in the Arctic. And since the ocean will only freeze if air temperatures are low enough, any process that raises air temperatures is going to delay refreeze.

The cup comparison repeats the same fallacy - the air that flows over the surface of the cup is a lot hotter than the surrounding air, and if we take the cup to be the open waters of the Arctic, then the surroundings of the cup are the rest of the Arctic. And blowing across the surface of the cup is going to warm up the surroundings faster than not blowing across the surface of the cup.

I think you are looking at the issue from the wrong side.  The water will freeze when the water surface temperature falls below freezing, regardless of the air temperature. 

Your tea cup analogy is good, in that air flowing across the cup will warm the surrounding air.  However, the more important point is that it cools the tea.  Wind is a good transport of heat, moving heat from hotter to colder surfaces.  Higher wind speed will facilitate heat loss from a warmer surface, cooling the surface faster than slower winds.  As winter approaches, the water will be warmer than the air as water retains heat (the reverse occurs in summer).  As the air cools, higher wind speeds will facilitate heat loss from the oceans.  Hence, the surface will freeze faster with higher wind speeds.

One final note.  High wind speeds create surface turbulence, which inhibits freezing initially.  Once the winds diminish, the surface will freeze.  This happens routinely in inland lakes, where cold winds cool the water surface, but freezing does not occur until the winds die down.  Then the entire lake freezes very quickly.
Title: Re: The 2020/2021 freezing season
Post by: Tor Bejnar on October 16, 2020, 03:46:47 PM
There is enough heat in the Arctic Ocean to keep the surface functionally or literally ice-free, we are told, but much of this heat is stored beneath the halocline.  With an ice-free surface, winds will cause the upper part of the Arctic Ocean to mix, making more of this heat available to the lower atmosphere (and beyond).  Stronger winds will remove heat from the surface of the water faster, but these stronger winds will also mix more of the water column.  At some point, with continuous-enough and strong-enough winds, the halocline will disappear and 'all' of the ocean heat becomes available to be transferred to the air.  And if what we're told is true, the Arctic Ocean will cease to freeze over.  With climate change, the "-enoughs" become more and more achievable, as the speed of heat removal from the lower atmosphere to outer space slows due to the thickening CO2e blanket.

If the autumn winds are really just breezes that minimally mix the water, then the water column below the halocline remains out of the picture [the hot plate, with 200 mm of insulation on top of it, on which the tea cup sits has 'no' influence on the blown-on cup of tea].  Here, the surface water cools faster with the breeze - faster than if there is no breeze - with time that heat transfers to space, or is replaced with an 'endless' supply of cold dry air from 'elsewhere'.  So with cooled water and the heat removed from the air above the water, ice can now form.  I'm pretty sure a breeze coming off the continents in October will speed up the surface cooling, thus hastening the surface freezing.
Title: Re: The 2020/2021 freezing season
Post by: gerontocrat on October 16, 2020, 04:25:50 PM
In the years 2007, 2012 and 2019, after the very low minimum sea ice extent in those years, extent sharply rebounded in the second half of October and the first few days in November. After that, for the remainder of the freezing season, extent gains were much more average in those years.

This was NOT the case in 2016. There was no massive increase in extent gains at that time or during the entire freezing season. As a result the March 2017 maximum was a record low. What was the difference? I'm not sure.

Perhaps even though 2019 had a higher AWP (i.e. potential) than 2016, clouds and inclement weather reduced the amount that AWP became real ocean heating, while in 2016 there was plenty of sunshine. If that is the case, then 2020 is similar to 2016. The GACC ensured that much of the AWP became real ocean heating, even though AWP was marginally below 2019. This suggests that large sea ice extent gains might not occur this year from now to early November (and beyond?)

The test will come in the next two to three weeks
Title: Re: The 2020/2021 freezing season
Post by: RoxTheGeologist on October 16, 2020, 07:39:47 PM

You ask about "the Arctic" and then concentrate solely on the surface of the ocean. Which is a fallacy. When heat escapes the sufarce on the ocean it raises air temperatures, but the heat is still in the Arctic. And since the ocean will only freeze if air temperatures are low enough, any process that raises air temperatures is going to delay refreeze.



Correct me if I misunderstand - the ocean and air both lose heat through emission of LWIR. Low air temperature doesn't cause the ocean to freeze; rather it is indicative of the physical conditions that cause freezing. If the ocean is warm, then the air above it will be warm as the ocean is so much more massive.
Title: Re: The 2020/2021 freezing season
Post by: pearscot on October 16, 2020, 07:40:39 PM
One thing I would like to remark on is the substantial wave action as of late on the Siberian side of the Arctic. To me, it is extremely important and I think it will have some profound effects. I realize the below image is created with models and is not 100% accurate, however current winds in that region are substantial and I think there are some significant waves.

Completely still water only needs to cool the very surface to the sea water freezing point, however during such wind events, mixing ensures that the ENTIRE column of water must reach that temperature in order to freeze during extremely strong winds. Moreover, I believe the effects of the winds will be twofold.

First, my understanding (and is shown in the animation of the stagnation and/or slight advancement of the Laptev Bite recently), that the current weather is affecting the ice edge and either stalling the melt or causing bottom melt. I would have to imagine 19ft waves crashing into the ice edge is going to cause some significant damage.

Second, and I think more importantly, (as Tor stated), the substantial waves are promoting mixing during a time in which the sea is SUPPOSED to be covered with ice. That cool surface layer is now being agitated and is in no way helping the ever-diminishing halocline layer. I don't know the long term implications of wave action in terms of how it affects the refreeze, but for me the most concerning aspect is the constant mixing during the transition period going into winter.

I think both of these are important components and will continue to define the Arctic in the modern era. Granted I cannot prove this as fact, but it is evident how streams can continue to flow well below freezing due to the water's movement.
Title: Re: The 2020/2021 freezing season
Post by: RoxTheGeologist on October 16, 2020, 07:51:33 PM
There is enough heat in the Arctic Ocean to keep the surface functionally or literally ice-free, we are told, but much of this heat is stored beneath the halocline.  With an ice-free surface, winds will cause the upper part of the Arctic Ocean to mix, making more of this heat available to the lower atmosphere (and beyond).  Stronger winds will remove heat from the surface of the water faster, but these stronger winds will also mix more of the water column.  At some point, with continuous-enough and strong-enough winds, the halocline will disappear and 'all' of the ocean heat becomes available to be transferred to the air.  And if what we're told is true, the Arctic Ocean will cease to freeze over.  With climate change, the "-enoughs" become more and more achievable, as the speed of heat removal from the lower atmosphere to outer space slows due to the thickening CO2e blanket.

If the autumn winds are really just breezes that minimally mix the water, then the water column below the halocline remains out of the picture [the hot plate, with 200 mm of insulation on top of it, on which the tea cup sits has 'no' influence on the blown-on cup of tea].  Here, the surface water cools faster with the breeze - faster than if there is no breeze - with time that heat transfers to space, or is replaced with an 'endless' supply of cold dry air from 'elsewhere'.  So with cooled water and the heat removed from the air above the water, ice can now form.  I'm pretty sure a breeze coming off the continents in October will speed up the surface cooling, thus hastening the surface freezing.

There will always be a halocline in the Arctic because of the inputs of freshwater from the rivers and through the Bering Strait. It is almost an enclosed ocean (like the black sea or the baltic).  The depth and extent of the halocline will reduce as amplification of the halocline through the freeze/thaw distillation process is a lot less effective, and there is more mixing without ice cover.
Title: Re: The 2020/2021 freezing season
Post by: FishOutofWater on October 16, 2020, 09:21:51 PM
There's a reason that meteorologists and scientists studying climate change use complex models with multiple independent variables. If we assume that the Arctic ocean is a cup of tea, then blowing on harder it will cool it more. I mean, what's wrong with the assumption? A cup of tea is bowl shaped and so is the Arctic ocean. Well, that is a starting point, but do we really want to reinvent climate modelling starting with the assumption that the Arctic ocean is like a cup of tea?

Anyone who has lived in a cold region can tell you that strong cold winds will cool off a lake faster than a still cold night with similar temperatures but if the lake is large enough, like a great lake, temperatures rise as the winds cross the lake. In fact, intense turbulence and extreme lake effect snow can develop. So it's already not hard to see why we can't apply the simple tea cup model to the Arctic ocean. It's a complicated problem that includes the effects of water vapor and clouds on outgoing radiation. The cloud tops radiate out at a much colder temperature than the sea surface so they reduce radiational cooling.

Research has shown - see Judah Cohen's blog and publications - that open water in the Barents and Kara seas leads to displacement of the polar vortex in the fall and winter months towards the Atlantic ocean. Moreover, the vortex is weakened by the warming subpolar seas on the Atlantic side. So we have a very complex problem with multiple coupled processes when we deal with increasing release of oceanic heat from the Arctic ocean in the fall and winter months.

We have a classic case of a weak tropospheric polar vortex now. (see figure) Heat release from the Arctic ocean is contributing to the dome of warm air over the Arctic, but much of the dynamics for it came from warmer than normal waters in the North Pacific and north Atlantic.

The immediate concern we face is the increasing Atlantification of the Eurasian side of the Arctic ocean. That is relevant to the weather and ice conditions we are watching today.
Title: Re: The 2020/2021 freezing season
Post by: Positive retroaction on October 16, 2020, 09:51:49 PM
  leads to displacement of the polar vortex in the fall and winter months towards the Atlantic ocean. Moreover, the vortex is weakened by the warming subpolar seas on the Atlantic side. So we have a very complex problem with multiple coupled processes when we deal with increasing release of oceanic heat from the Arctic ocean in the fall and winter months.
Totaly agree
This is what is happening right now
Watch the jet stream outgrowth over Western Europe and the North East Atlantic
It's been several weeks since this has been happening without interruption, and the cold weather that it generated in France has drawn attention, we went from summer to winter without transition (in france we are living the coldest autumn period since 1974)!
We can see also how disorganized and low is the polar vortex in this moment on the Atlantic ans European side
Title: Re: The 2020/2021 freezing season
Post by: A-Team on October 17, 2020, 12:11:51 AM
Quote
There's a reason scientists studying climate change use complex models not tea cups
Right. The discussion has not been at the level of the mid-1700's.

How many people here can expand the acronym SHEBA -- was there a need or could it all have been intuited from gedanken experiments?

Worst freeze season ever underway ... would never know it from the posts. How can 1 person on twitter (https://twitter.com/ZLabe) cover it better than 1777 persons?

1738 – Daniel Bernoulli publishes Hydrodynamica, initiating the kinetic theory
1749 – Émilie du Châtelet derives the conservation of energy from Newtonian mechanics.
1761 – Joseph Black shows ice absorbs heat without changing its temperature when melting
1772 – Dan Rutherford discovers nitrogen which he explains in terms of phlogiston theory
1776 – John Smeaton paper on power, work, momentum, and kinetic energy
1777 – Carl Scheele distinguishes heat transfer by thermal radiation from convection and conduction
1783 – Tony Lavoisier discovers oxygen and develops caloric explanation for combustion
1784 – Jan Ingenhousz describes Brownian motion of charcoal particles on water
1791 – Pierre Prévost shows that all bodies radiate heat, no matter how hot or cold they are

Here's what we are watching unfold (Oct 11):

(https://forum.arctic-sea-ice.net/index.php?action=dlattach;topic=3299.0;attach=288481;image)
Title: Re: The 2020/2021 freezing season
Post by: Cook on October 17, 2020, 12:52:33 AM
One thing I would like to remark on is the substantial wave action as of late on the Siberian side of the Arctic. To me, it is extremely important and I think it will have some profound effects. I realize the below image is created with models and is not 100% accurate, however current winds in that region are substantial and I think there are some significant waves.

Completely still water only needs to cool the very surface to the sea water freezing point, however during such wind events, mixing ensures that the ENTIRE column of water must reach that temperature in order to freeze during extremely strong winds. Moreover, I believe the effects of the winds will be twofold.

First, my understanding (and is shown in the animation of the stagnation and/or slight advancement of the Laptev Bite recently), that the current weather is affecting the ice edge and either stalling the melt or causing bottom melt. I would have to imagine 19ft waves crashing into the ice edge is going to cause some significant damage.

Second, and I think more importantly, (as Tor stated), the substantial waves are promoting mixing during a time in which the sea is SUPPOSED to be covered with ice. That cool surface layer is now being agitated and is in no way helping the ever-diminishing halocline layer. I don't know the long term implications of wave action in terms of how it affects the refreeze, but for me the most concerning aspect is the constant mixing during the transition period going into winter.

I think both of these are important components and will continue to define the Arctic in the modern era. Granted I cannot prove this as fact, but it is evident how streams can continue to flow well below freezing due to the water's movement.

I think you are on the money with this. The difference between a well mixed salty sea and one that is poorly mixed with a fresh top layer is very significant.  It will be fascinating to watch how this plays out.
Title: Re: The 2020/2021 freezing season
Post by: passenger66 on October 17, 2020, 01:18:18 AM
How can 1 person on twitter (https://twitter.com/ZLabe) cover it better than 1777 persons?
I do think Gerontocrat is pointing this out in his daily updates e.g. "Average remaining extent gain (of the last 10 years) would produce a maximum in March 2021 of 13.04 million km2, 0.84 million km2 below the March 2017 record low maximum of 13.88 million km2."
Title: Re: The 2020/2021 freezing season
Post by: binntho on October 17, 2020, 03:45:55 AM
Correct me if I misunderstand - the ocean and air both lose heat through emission of LWIR.
I'm not sure what you mean here. Everything is constantly losing and gaining heat from emssion or abosrbtion of long-wave radiation. But this is not an effective heat transfer mechanism at atmospheric temperatures. Conduction and convection are much more effective, and both are at play at the wind/water interface.

The atmosphere loses heat into space from the top of the atmosphere (as Aslan pointed out above (https://forum.arctic-sea-ice.net/index.php/topic,3299.msg289984.html#msg289984)), not from the surface of the ocean. And the more water (vapor and clouds) in the atmosphere, the less heat is radiated out.
Title: Re: The 2020/2021 freezing season
Post by: binntho on October 17, 2020, 03:53:43 AM
Quote
There's a reason scientists studying climate change use complex models not tea cups
Right. The discussion has not been at the level of the mid-1700's.

How many people here can expand the acronym SHEBA -- was there a need or could it all have been intuited from gedanken experiments?

A little less of that olde time sarcasm, Oren says. But keep it coming, says I, it shines a light into our doldrums.

A lot of us posting here are interested laymen with very different levels of background knowledge. Thought experiments are one way for us to try to understand what is happening, to try to visualise it.

And SHEBA is bloody hard to understand (not the queen, though, being made up and all), let alone trying to explain to others, not to mention getting them to understand it. Which I don't, but I'm trying.
Title: Re: The 2020/2021 freezing season
Post by: El Cid on October 17, 2020, 08:03:20 AM
Everyone, thank you for your contributions! (and sorry for the poor analogy).

I know that it is complex system (not for nothing do weather models run on supercomputers) where everything has an effect on everything else with possible chaotic events and system changes.

As for gerontocrat's dilemma (whether this time we will follow 2019's or 2016's lead), i don't have the answer (probably none of us do) but I attach SST anomaly maps for 2016 vs 2020 and 2019 vs 2020.

The Laptev and ESS is warmer than ever. However, the Barents and Kara are colder than they were in 2016 but warmer than in 2019. I would say a very slow refreeze is likely...
Title: Re: The 2020/2021 freezing season
Post by: HapHazard on October 17, 2020, 08:26:51 AM
I would say a very slow refreeze is likely...

I would think so! :

[ADS NIPR VISHOP (JAXA)] Arctic Sea Ice Extent.

October 16th, 2020:
     4,928,965 km2, a drop of -9,602 km2.  :o
Title: Re: The 2020/2021 freezing season
Post by: oren on October 17, 2020, 11:16:19 AM
In the years 2007, 2012 and 2019, after the very low minimum sea ice extent in those years, extent sharply rebounded in the second half of October and the first few days in November. After that, for the remainder of the freezing season, extent gains were much more average in those years.

This was NOT the case in 2016. There was no massive increase in extent gains at that time or during the entire freezing season. As a result the March 2017 maximum was a record low. What was the difference? I'm not sure.
So what happens in October and what happened in 2016? October is the month when the Siberian seas: ESS, Laptev and usually Kara freeze over, as can be seen in the cropped Wipneus NSIDC extent graphic. That is a huge region of 2.6M km2. However 2016 (the blue line) had a confluence of events. It saw half the ESS refreeze pushed to November, and the Kara pushed to late Nov and December.
Meanwhile, 1M km2 of Hudson Bay which usually freezes in Nov was pushed to early Dec., which is why no Nov spike appeared. December saw delays in the Chukchi and the Barents. Thus a cascade of events made the October spike disappear altogether.

This year, I fully expect the Siberian seas to have a delayed refreeze, though refreeze they eventually will. So the October spike will almost certainly not happen, but it is quite plausible that it will appear in November and/or December.
Title: Re: The 2020/2021 freezing season
Post by: FishOutofWater on October 17, 2020, 11:22:32 AM
Yep, worst start to a freezing season we have ever seen. The maps at Climate reanalyzer are crazy.

The northern hemisphere temperature anomalies are huge for both the air and the oceans. In the southern hemisphere La Niña is cranking up with intense atmospheric convection over Indonesia, strong trade winds across the Pacific and intense upwelling along the coast of South America and along the equator in the eastern Pacific. There is now a large imbalance in the thermal anomalies and the Arctic is where the largest warm anomalies are found.

The heat content of the north Atlantic is at record high levels in the historic record, and according to proxies the past 2000 years or more. This is a set up for a winter with a weak polar vortex and strong intrusions of warm air from both the Atlantic and Pacific oceans - a poor freezing season. ON the other hand, there's a fair chance of w midwinter sudden stratospheric warming and strong high pressure over the pole which could enhance midwiinter freezing. There is hope that after a record poor start to the freezing season that January through March could be good for new ice. I think there's a better than average chance of a SSW this winter given the La Niña and westerly QBO.
Title: Re: The 2020/2021 freezing season
Post by: Niall Dollard on October 17, 2020, 01:43:32 PM
Large area of old ice just north of Severnaya Zemlya is almost separated from the main pack. Only a thin channel of about 20cm thick ice connecting it.
Title: Re: The 2020/2021 freezing season
Post by: Shared Humanity on October 17, 2020, 02:08:52 PM
Large area of old ice just north of Severnaya Zemlya is almost separated from the main pack. Only a thin channel of about 20cm thick ice connecting it.

Due to those persistent easterly winds across the Siberian side of the Arctic we have been experiencing for the past 6 weeks. Normally a healthy freeze would fill in the leads that are created but the SST temps are too high for this. This is unusual.
Title: Re: The 2020/2021 freezing season
Post by: Yuha on October 17, 2020, 02:44:08 PM
This was NOT the case in 2016. There was no massive increase in extent gains at that time or during the entire freezing season. As a result the March 2017 maximum was a record low. What was the difference? I'm not sure.

I seem to recall that in 2016 from October to December there was a series of Atlantic storms entering the Arctic and bringing a lot of heat with them. These can be seen as spikes in the DMI temp chart.
Title: Re: The 2020/2021 freezing season
Post by: BornFromTheVoid on October 17, 2020, 04:18:34 PM
Here's an animation comparing the first 16 days of October with 2012
A slightly large file, ~7mb. Click to play.
(larger/better quality version is up on twitter: https://twitter.com/Icy_Samuel/status/1317469236709777416).
Title: Re: The 2020/2021 freezing season
Post by: Freegrass on October 17, 2020, 04:48:26 PM
Latest Five Day Forecast + Last 24h
Wind + Temp @ Surface
Large GiF!

Missed one yesterday because of alcohol day, so I added the last 24 hours as well.
Title: Re: The 2020/2021 freezing season
Post by: binntho on October 17, 2020, 04:51:13 PM
I've been looking at extent maps for the different years, trying to see if there is an obvious difference. And a thought (or "gedanken" as the clever people call it) struck me: Is this the first year when the entire Siberian shelf is ice free? An if so, could that make a signifcant difference to this freezing season - and why?
Title: Re: The 2020/2021 freezing season
Post by: jai mitchell on October 17, 2020, 05:08:32 PM
I truly thought we would beat the 2012 minimum this year due to a massive decrease in global aerosol loading.  But we didn't.
Same here... But we did almost beat 2012 without a GAC or Dipole, and the temperatures were record breaking in the arctic. So that theory isn't dead IMHO...

Let's see what winter brings!

With reduced aerosols, I would expect a slight reduction in upper troposphere humidity with a (barely perceptible) reduction in temperatures during the Arctic Winter.
Title: Re: The 2020/2021 freezing season
Post by: oren on October 17, 2020, 05:33:35 PM
Here's an animation comparing the first 16 days of October with 2012
Thanks BFTV. It seems to me that the regions that were late to melt are early to freeze in both years. If true, this is probably due to the mixing that goes on when a region has been ice free for a longer period.
Title: Re: The 2020/2021 freezing season
Post by: BornFromTheVoid on October 17, 2020, 06:26:45 PM
Thanks BFTV. It seems to me that the regions that were late to melt are early to freeze in both years. If true, this is probably due to the mixing that goes on when a region has been ice free for a longer period.

Cheers.
A useful comparison might the the date of ice loss (1st attachement) next to the October gain (2nd attachment). Judging by this, we should expect the Laptev sea to have the most difficult time freezing over.
This appears to be supported by the higher SST anomalies in the region currently.


Title: Re: The 2020/2021 freezing season
Post by: morganism on October 17, 2020, 08:11:54 PM
With the shallow ESS ice free, does the extra methane produce more lenticular clouds, capping heat transfer to space?
Title: Re: The 2020/2021 freezing season
Post by: binntho on October 17, 2020, 09:07:10 PM
With the shallow ESS ice free, does the extra methane produce more lenticular clouds, capping heat transfer to space?
Do you mean noctilucent clouds?
Title: Re: The 2020/2021 freezing season
Post by: HapHazard on October 17, 2020, 10:23:19 PM
Proposed possibility: the Siberian shelf might be taking a leap forward in its Atlantification schedule.

I'd love to be wrong. Usually am, here. heh
Title: Re: The 2020/2021 freezing season
Post by: Aluminium on October 18, 2020, 08:52:35 AM
October 13-17.

2019 (https://forum.arctic-sea-ice.net/index.php/topic,2888.msg233556.html#msg233556).
Title: Re: The 2020/2021 freezing season
Post by: jdallen on October 18, 2020, 10:12:02 AM
Quote
There's a reason scientists studying climate change use complex models not tea cups
<snip>
Worst freeze season ever underway ...
<snip>
Concur.  As I observed in the extent and area thread, the numbers on the eastern side of the basin - Kara, Barents, ESS and Laptev - are terrifying.

As FooW observes, this is already having an impact on northern hemisphere circulation and weather.

While the Beaufort and Chukchi numbers are not at record breaking levels, they are not good, and the sea surface temperatures are very much so.

Looking back at another question up thread about the influence of this all... you touch on it by way of stating the heat to melt the ice year round is already present in the Arctic, it just isn't accessible... the net enthalpy in the Arctic is rising almost exponentially, and combined with the observed destruction of the haloclines in the Atlantic side of the Arctic is a dire portent for the very near future. 

The buffers which used to keep a lid on that heat are gone.  Lack of ice growth will merely be a symptom.  The real story will play out in the changes we are going to see in winter weather in the northern hemisphere.

What happens with the weather next spring will be definitive in ways humanity has not experienced in over 10,000 years.  There is simply too much heat loose in the northern hemisphere.

The analogy I think of is one which actually came from my study of geology/vulcanology.  It ties back to the observation of events prior to a phreatic explosion at the rim of a atoll volcano.  Prior to the explosion, there were major jets of steam venting from the area which would later explode.  Someone asked if that would be sufficient for the energy to dissipate.  The point made then was that the steam jets were akin to a giant sticking his finger through the hole in the roof of a hut.  There was no way the giant was going to climb through it, nor would the roof of the hut be enough to contain him.

So it is with the increase in enthalpy in the Arctic.  What we are seeing now in fact is the culmination of years of build up and Atlantification, probably starting before 2012, probably before 2007. 

The last few years, we've watched the giant sticking his finger through a hole in the roof.  I think we are about to see him emerge.
Title: Re: The 2020/2021 freezing season
Post by: El Cid on October 18, 2020, 11:01:50 AM
  The real story will play out in the changes we are going to see in winter weather in the northern hemisphere....  I think we are about to see him emerge.


I think the Siberian seas are going through Hudsonization: from now on they will quickly melt out in June/July and then stay open for long and then suddenly freeze over in a short timeframe (2-3 weeks) during November or early December.

how this will change NH winters is anyone's guess
Title: Re: The 2020/2021 freezing season
Post by: gerontocrat on October 18, 2020, 11:19:13 AM
  The real story will play out in the changes we are going to see in winter weather in the northern hemisphere....  I think we are about to see him emerge.


I think the Siberian seas are going through Hudsonization: from now on they will quickly melt out in June/July and then stay open for long and then suddenly freeze over in a short timeframe (2-3 weeks) during November or early December.

how this will change NH winters is anyone's guess
I think you are a bit behind the curve. Winter sea ice is now looking vulnerable.

The Barents has already lost half its winter sea ice compared with the 1980's, and even that is looking vulnerable.

The Kara sea freeze continues into January / February and in some years does not fully freeze up.

And the same to a lesser extent with the Laptev & ESS.


Title: Re: The 2020/2021 freezing season
Post by: BornFromTheVoid on October 18, 2020, 12:58:16 PM
Latest slow animation, 12th to 17th
Title: Re: The 2020/2021 freezing season
Post by: El Cid on October 18, 2020, 02:18:47 PM

I think the Siberian seas are going through Hudsonization: from now on they will quickly melt out in June/July and then stay open for long and then suddenly freeze over in a short timeframe (2-3 weeks) during November or early December.
I think you are a bit behind the curve.

Yes, I might be behind the curve in many ways :)

I actually meant the Laptev and the ESS as the Barents (and some ways the Kara) has already fallen. I think that as these two (ESS,Laptev) are quite closed to the warmer oceans (unlike the Barents-Kara complex), so their behaviour should soon be like the Hudson (also pretty closed): very quick meltout during summer and late but fast refreeze. And the past few years are obvioulsy going into this direction. I just expect these processes to be even faster then now.
Title: Re: The 2020/2021 freezing season
Post by: be cause on October 18, 2020, 03:31:51 PM
a bit holey around the pole eh ? ..
https://go.nasa.gov/3lVesaU .. b.c.
Title: Re: The 2020/2021 freezing season
Post by: Général de GuerreLasse on October 18, 2020, 03:40:15 PM
Yep, worst start to a freezing season we have ever seen. The maps at Climate reanalyzer are crazy.

There is hope that after a record poor start to the freezing season that January through March could be good for new ice. I think there's a better than average chance of a SSW this winter given the La Niña and westerly QBO.

Hi FishOutofWater,
What does SSW mean? I couldn't find anything in the glossary. Thank you
Title: Re: The 2020/2021 freezing season
Post by: dnem on October 18, 2020, 03:42:22 PM
https://en.wikipedia.org/wiki/Sudden_stratospheric_warming
Sudden stratospheric warming
Title: Re: The 2020/2021 freezing season
Post by: gandul on October 18, 2020, 03:51:20 PM
@A-team.
Interesting papers, and more interesting is to note that Polyakov et al 2020 that you have brought several times has that conclusion (a mechanism by which Atlantic heat might be reaching the Laptev sea and perhaps this venting become permanent) as “hypothesis” (hopefully testable, otherwise a conjecture), not a fact as quickly taken by others here. It is not a fact that this hopefully testable conjecture has anything to do with current Arctic situation, it is not a fact that Atlantic heat is reaching the surface of the Arctic proper, and it is not a fact that this is a positive feedback.

<Slight edit. O>
Title: Re: The 2020/2021 freezing season
Post by: Shared Humanity on October 18, 2020, 04:27:41 PM
Here's an animation comparing the first 16 days of October with 2012
A slightly large file, ~7mb. Click to play.
(larger/better quality version is up on twitter: https://twitter.com/Icy_Samuel/status/1317469236709777416).

Notable in that gif is the rapid refreeze in 2012 of the open water in the Chukchi and ESS. I think this is directly related to the late season, rapid melt of a large amount of sea ice that had virtually separated from the main pack. The GAC melted a lot of ice but very late in the season and this cold, fresh water lens was primed to refreeze rapidly. This is not the case this year and we should expect the freeze on the Siberian side to continue to be slow.

https://forum.arctic-sea-ice.net/index.php?action=dlattach;topic=3299.0;attach=288830;image
Title: Re: The 2020/2021 freezing season
Post by: oren on October 18, 2020, 04:29:58 PM
Gandul, I haven't read the paper itself yet but I get the feeling you are misreading this paragraph. While the positive feedback (reduced sea ice => higher mixing rates => reduced sea ice) is a (very reasonable) hypothesis, the increased coupling of AW heat and the sea ice is not, if I read this correctly.
Title: Re: The 2020/2021 freezing season
Post by: Général de GuerreLasse on October 18, 2020, 05:36:10 PM
Yep, worst start to a freezing season we have ever seen. The maps at Climate reanalyzer are crazy.

 ON the other hand, there's a fair chance of w midwinter sudden stratospheric warming and strong high pressure over the pole which could enhance midwiinter freezing.

Hi FishoutofWater,
Why do you think an SSW will automatically bring more cold to the Arctic?
Here is an excerpt from a 2018 Infometeo.be article. I hope the GIF will work. According to the GIF it's the heat that spreads on the ice after the polar vortex explosion after the SSW appeared. I'm a beginner, sorry if I missed something obvious. ;)
https://imeteo.be/2018/02/12/eclatement-vortex-polaire-consequences-meteo/

In the introduction, we were talking about a sudden stratospheric warming. As the name suggests, this is a sudden increase in temperature in the stratosphere. This change disrupts the temperature gradient that makes the vortex exist. Destabilized by this heat attack, the vortex eventually burst, which profoundly changed the wind regime in the stratosphere. The animation below, taken from the GFS model of a few days ago, shows the destabilization of the cold air mass (in blue) of the polar vortex by warmer air, this warm wave coming here from the troposphere.

GIF needs a click to run

Title: Re: The 2020/2021 freezing season
Post by: oren on October 18, 2020, 05:40:00 PM
Yep, worst start to a freezing season we have ever seen. The maps at Climate reanalyzer are crazy.

There is hope that after a record poor start to the freezing season that January through March could be good for new ice. I think there's a better than average chance of a SSW this winter given the La Niña and westerly QBO.

Hi FishOutofWater,
What does SSW mean? I couldn't find anything in the glossary. Thank you
Thanks, GdGL. I was sure SSW was in the glossary already. Added now.
Title: Re: The 2020/2021 freezing season
Post by: Freegrass on October 18, 2020, 06:33:24 PM
With the refreeze delayed, and melting coming earlier, what effect does that have on the halocline? If I understand correctly, it's ice production that creates saltier water that adds to the thickness of the halocline, right? So with less ice production, this should have a negative effect on the halocline, right? And a weak halocline prevents freezing, which is another negative feedback loop? Am I getting that right?
Title: Re: The 2020/2021 freezing season
Post by: gandul on October 18, 2020, 06:48:11 PM
Gandul, I haven't read the paper itself yet but I get the feeling you are misreading this paragraph. While the positive feedback (reduced sea ice => higher mixing rates => reduced sea ice) is a (very reasonable) hypothesis, the increased coupling of AW heat and the sea ice is not, if I read this correctly.
You read as I read. But the hypothesis here in particular is that there are mechanisms the enhanced turbulence due to shear and not diminished due to lack of ice will be able to breach the stratification and bring heat from the Atlantic Water.

Is it reasonable? I don’t know, I thought the top of this layer was 50 to 150m and a big storm like the GAC 2012 apparently was unable to pull energy from more than 50m (and that was a feat). But if these guys see it possible, I accept it, but as a hypothesis, not a fact. This forum is an echo chamber and pretty soon everyone will be accepting the Atlantification of Laptev sea as a fact.
Title: Re: The 2020/2021 freezing season
Post by: oren on October 18, 2020, 07:10:28 PM
Thanks for the clarification. I think the mixing in question is not about pulling energy from below but about losing the freshwater lens and getting higher surface salinity. But hey, maybe I should finally find the time to read the paper...
In any case, I don't feel this forum is an echo chamber.
Title: Re: The 2020/2021 freezing season
Post by: Freegrass on October 18, 2020, 07:44:01 PM
Latest Five Day Forecast
Wind @ Surface + Total Precipitable Water
Wind + Temp @ 850hPa
Large GiFS!
Title: Re: The 2020/2021 freezing season
Post by: Positive retroaction on October 18, 2020, 09:02:56 PM
Gandul, I haven't read the paper itself yet but I get the feeling you are misreading this paragraph. While the positive feedback (reduced sea ice => higher mixing rates => reduced sea ice) is a (very reasonable) hypothesis, the increased coupling of AW heat and the sea ice is not, if I read this correctly.
You read as I read. But the hypothesis here in particular is that there are mechanisms the enhanced turbulence due to shear and not diminished due to lack of ice will be able to breach the stratification and bring heat from the Atlantic Water.

Is it reasonable? I don’t know, I thought the top of this layer was 50 to 150m and a big storm like the GAC 2012 apparently was unable to pull energy from more than 50m (and that was a feat). But if these guys see it possible, I accept it, but as a hypothesis, not a fact. This forum is an echo chamber and pretty soon everyone will be accepting the Atlantification of Laptev sea as a fact.

Hello,
This is an extract of one of the researchs in the Arctic about haloclin
excuse me, I don't see any assumptions here, but conclusions supported by measurements made on several points during 15 years, it is not the same thing. Some points are not well understood in arctic, but the weakening of the halocline is well noted

"Time series measurements from a 15-yr mooring record in the eastern EB of the Arctic Ocean demonstrate that the previously identified weakening of stratification over the halocline, which isolates intermediate depth AW from the sea surface, over the period 2003–15 (e.g., Polyakov et al. 2017, 2018), has continued at an increasing rate in more recent years (2015–18). In consequence, oceanic heat fluxes for the winters of 2016–18 are estimated to be greater than 10 W m−2. These fluxes are substantially larger than the previously reported winter estimates for the region for 2007/08 of 3–4 W m−2 (Lenn et al. 2009; Polyakov et al. 2019) and comparable to the estimates for the winters of 2013–15 (Polyakov et al. 2017), implying a significant enhancement of the role of oceanic heat in this region in recent years.

Moreover, the increased vertical heat fluxes have been accompanied by increased upper-ocean current speeds |U| and the magnitude of vertical shear in the horizontal velocities |Uz| over the period 2015–18 (Polyakov et al. 2020b, manuscript submitted to Geophys. Res. Lett.). Using mooring observations from 2003 to 2018, these authors showed that time-averaged values of |U| and |Uz| in the upper 60 m of the water column increased by about 20% and 40%, respectively. In the lower halocline (110–140 m), |U| was generally larger after 2008, increasing on average from 2.5–3.5 cm s−1 in 2003–08 to about 4–5 cm s−1 in 2009–18 (Figs. 3c,d) although the change was not as strong in very recent years, 2016 and 2018, when compared to 2009–15. There is also a clear transition in |Uz|, with significantly larger shears evident post-2010, and in particular in the summer of 2018 (Figs. 3c,d). However, Pnyushkov et al. (2018a) found no significant change in the mean along-slope water transport over the same period.

The combination of reduced stratification and increased shear implies a decrease of the gradient Richardson number (Ri) defined in section 3 (Figs. 3e,f), consistent with an increased turbulent heat flux, associated with vertical mixing by shear instabilities. Although the Ri estimates are based on 20 m vertical resolution measurements, they show a clear trend toward reduced dynamic stability, which may be interpreted as a tendency toward increased turbulent mixing in recent years, coincident with the increase in maximum halocline heat content (Fig. 4). This tendency is particularly strong in 2018 with amplified velocity shear in the relatively weakly stratified upper ocean (Fig. 3)."

https://journals.ametsoc.org/jcli/article/33/18/8107/353233/Weakening-of-Cold-Halocline-Layer-Exposes-Sea-Ice

And. we spoked about effets if wind a few post before
This is an other action, winds increase thé CO2 from the athmosphere from the oceans
"The combination of open leads (i.e. lower ice concentration) and strong winds likely enabled large fluxes of heat, moisture, and gases between the ocean and atmosphere at these times56,57. For example, Fransson et al.57 estimated that the CO2 flux from the atmosphere into the ocean was approximately 20 times higher during storm periods, compared with average wind speed conditions and fewer open leads57."
https://www.nature.com/articles/s41598-019-45574-5

And about thé effet if wind cause deep mix or only surface mix in the océan, how deep are this effets?
 "I don’t know, I thought the top of this layer was 50 to 150m and a big storm like the GAC 2012 apparently was unable to pull energy from more than 50m (and that was a feat). But if these guys see it possible, I accept it, but as a hypothesis, not a fact. "
An other fact hère
Légend is:
"Time series of atmospheric, sea-ice, and oceanographic observations during the first two N-ICE2015 ice drifts in January–March 2015"
note that this does not concern an ice free area but an area with good concentration, in march with halocline thick
Légend for the ultimate diagram
"Ocean mixing given by dissipation rate60 (colour bar, warm colours correspond to stronger mixing), mixed layer depth62 (black line), and presence of Atlantic Water (red bar). Bold red bar indicates Atlantic Water (>2 °C) shallower than 250 m62. The two drift periods are highlighted by black bars in top of panel (a). Storm periods (M1-M6) are shaded as in Fig"

Please note the deep of mixed water, despite of the good ice concentration
Image here (i can't importe it, cause HTML sorry)
https://media.springernature.com/full/springer-static/image/art%3A10.1038%2Fs41598-019-45574-5/MediaObjects/41598_2019_45574_Fig5_HTML.png?as=webp
Title: Re: The 2020/2021 freezing season
Post by: morganism on October 18, 2020, 09:39:13 PM
 (yes, meant noctilucent clouds. 

Looks like someone did a study in Alaska this year, and reported 50% of days in "season" (may til august) had NLCs, and that they were getting lower, and showed some "growth sedimentation mechinism"

http://ffden-2.phys.uaf.edu/atm/atm/theses/2020/Alspach,%20Jennifer_Thesis.pdf

looks like the sattelite is still operational

http://aim.hamptonu.edu/mission/status.php

http://aim.hamptonu.edu/

"The season continues to be a strong one, as shown in the figure. Throughout the 2020 season, daily PMC frequencies have exceeded frequencies in all or most previous years. Although not shown, this is consistent with lower-than-typical temperatures and higher-than-typical water vapor mixing ratios, as measured by the NASA Microwave Limb Sounder. These conditions are consistent with low solar activity, but definitive attribution is still under investigation."
Title: Re: The 2020/2021 freezing season
Post by: jdallen on October 19, 2020, 02:37:06 AM
Gandul, I haven't read the paper itself yet but I get the feeling you are misreading this paragraph. While the positive feedback (reduced sea ice => higher mixing rates => reduced sea ice) is a (very reasonable) hypothesis, the increased coupling of AW heat and the sea ice is not, if I read this correctly.
<snippage>
I accept it, but as a hypothesis, not a fact. This forum is an echo chamber and pretty soon everyone will be accepting the Atlantification of Laptev sea as a fact.

Don't take our word for it.

You can listen to the mute testimony of Emiliania Huxleyi (EHux).

It is coming, in fact, in progress.

https://www.nature.com/articles/s41467-020-15485-5
Title: Re: The 2020/2021 freezing season
Post by: A-Team on October 19, 2020, 03:43:10 AM
Freeze-up is still going very slowly and asymmetrically, with the 'lower half' more or less normal and the 'upper half' on the Siberian side still stalled. The first two images below measure the disappearance of open water using pixel counts on AMSR2_AWI.

Because of the over-weighting brought in by the Beaufort, it is more instructive to measure the upper half separately, defined here by a line between Utqiagvik and eastern NovZem. The light blue data show not quite 7% loss of open water during the first 17 days of October.

Looking now at sea surface temperature, mixed layer depth, and surface salinity at the revolutionary new CMEMS-Lobelia tool, this unprecedented situation seems likely to continue well into November where it will be even farther outside natural variation than ever, consistent with the zonal vertical mixing data, marine dominance and tipping point analysis described in Polyakov 2019, 2020.

Atlantification of the Laptev has been slowly underway for decades according to those two papers (and 60 earlier journal articles cited) but de-stratification has gotten to the point where AW heat nearer the surface is seriously affecting the ability of fall weather to form ice. The Laptev will freeze over at some point but the ice formed will be thinner, weaker, brine-pocketed and more mobile by the beginning of melt season. We have no idea if, when and where Transpolar Drift winds will set up this fall but the combination could lead to a damaging trend.

https://tinyurl.com/y6zvqdwa

Technical note: the sea surface temperature uses kelvin in which system the freezing point of 32 psu seawater is 271.35. The display bound were then set ±7 around that; these work very similar to Nasa's worldview 'squeeze palette'. Then a divergent palette was selected, causing middle white to be the freezing point and blue/red colors to be the departure. Per NSIDC, each five units of change in salinity affect the freezing point by 0.28ºC so only very small errors are introduced over the current range of open water Arctic salinities. Grayscale salinities were contoured with the G'MIC filter in Gimp.
Title: Re: The 2020/2021 freezing season
Post by: oren on October 19, 2020, 06:00:22 AM
Have finally read Polyakov 2020, very good paper and very concerning. Thanks A-Team for bringing it to our attention.
I also recommend reading the new Jennifer Francis paper, though I can't give an intelligent opinion about its contents.

I don't think I've seen this new Jennifer Francis paper referenced on the ASIF:
https://www.woodwellclimate.org/why-has-no-new-record-minimum-arctic-sea-ice-extent-occurred-since-september-2012/

https://iopscience.iop.org/article/10.1088/1748-9326/abc047
Abstract
One of the clearest indicators of human-caused climate change is the rapid decline in Arctic sea ice. The summer minimum coverage is now approximately half of its extent only 40 years ago. Four records in the minimum extent were broken since 2000, the most recent occurring in September 2012. No new records have been set since then, however, owing to an abrupt atmospheric shift during each August/early-September that brought low sea-level pressure, cloudiness, and unfavorable wind conditions for ice reduction. While random variability could be the cause, we identify a recently increased prevalence of a characteristic large-scale atmospheric pattern over the northern hemisphere. This pattern is associated not only with anomalously low pressure over the Arctic during summer, but also with frequent heatwaves over East Asia, Scandinavia, and northern North America, as well as the tendency for a split jet stream over the continents. This jet-stream configuration has been identified as favoring extreme summer weather events in northern mid-latitudes. We propose a mechanism linking these features with diminishing spring snow cover on northern-hemisphere continents that acts as a negative feedback on the loss of Arctic sea ice during summer.
Title: Re: The 2020/2021 freezing season
Post by: sailor on October 19, 2020, 11:17:52 AM

[...]

Looking now at sea surface temperature, mixed layer depth, and surface salinity at the revolutionary new CMEMS-Lobelia tool, this unprecedented situation seems likely to continue well into November where it will be even farther outside natural variation than ever, consistent with the zonal vertical mixing data, marine dominance and tipping point analysis described in Polyakov 2019, 2020.

Atlantification of the Laptev has been slowly underway for decades according to those two papers (and 60 earlier journal articles cited) but de-stratification has gotten to the point where AW heat nearer the surface is seriously affecting the ability of fall weather to form ice. The Laptev will freeze over at some point but the ice formed will be thinner, weaker, brine-pocketed and more mobile by the beginning of melt season. We have no idea if, when and where Transpolar Drift winds will set up this fall but the combination could lead to a damaging trend.

https://tinyurl.com/y6zvqdwa


Thank you A-Team, for all this clear exposition. I really enjoyed reading all this scientifically well informed discussion in this thread, and I thank Binntho, Aslan, Fish, Oren (and the rest) for the very interesting interchange that ensued after I wrote my brief "Late refreeze -> Energy lost" negative feedback comment.

Clearly I was not informed the so many mechanisms (oceanic but also of atmospheric disruption) in motion. This was a good "intensive course" week :-)

2019 had a slow refreeze until late October. 2020 is following the same path at least till mid-October. I'd wager a guess that "slow refreeze" is the new normal.

This is "good", in the sense that, although the Arctic seas contain more energy that the yesteryears, it is a recognized negative feedback that same Arctic seas are so wide open that refreeze is hard to come, and a lot of this energy excess is lost in the process. Otherwise Arctic sea ice would be collapsing much faster.
Title: Re: The 2020/2021 freezing season
Post by: Freegrass on October 19, 2020, 01:18:21 PM
Latest Five Day Forecast
Wind + Temp @ Surface
Large GiF!

The ESS/Chukchi is starting to look a lot like the Barents...
Title: Re: The 2020/2021 freezing season
Post by: aslan on October 19, 2020, 03:59:11 PM
For what is worth (not much, admittedly), but the surface analysis of GFS (the GDAS) did not show a significant drop for SST during the week-end. The image is the difference of surface temperature (sea or land) between the 19 at 00Z and the 15 at 00Z. Over land, there is definitively nothing to analysis. However, for SST, even though not too much weight has to be given, it is still showing something. Surface analysis even show some patches of more than 1°C rise in SST. But what all this show is that the storm did not lead to a massive drop in SST.

P.S. : Better image this way
Title: Re: The 2020/2021 freezing season
Post by: BornFromTheVoid on October 19, 2020, 05:12:39 PM
Zach Labe pointed out on twitter that the 5 day mean NSIDC extent has reached the largest negative anomaly on record (relative to 1981-2010).

I had a check, and this is true for the daily data too. In fact, each of the last 5 days have set a new record large -ve anomaly.

The previous record was 3.068 million km2, on October 8th 2012.
The last 5 days, October 14th to 18th, are:
-3.088
-3.128
-3.167
-3.209
-3.275



Title: Re: The 2020/2021 freezing season
Post by: Shared Humanity on October 19, 2020, 05:54:12 PM
Does an increase in SST after a storm suggest that warm Atlantic or Pacific waters have surfaced due to waves mixing the surface layer with deeper waters? If this is true, could continued high winds and 3 to 5 meter waves keep this mixing going and delay freeze even further?
Title: Re: The 2020/2021 freezing season
Post by: El Cid on October 19, 2020, 06:27:19 PM
Does an increase in SST after a storm suggest that warm Atlantic or Pacific waters have surfaced due to waves mixing the surface layer with deeper waters? If this is true, could continued high winds and 3 to 5 meter waves keep this mixing going and delay freeze even further?

Great question. I asked the same about 3 days ago upthread.
Title: Re: The 2020/2021 freezing season
Post by: Freegrass on October 19, 2020, 06:54:03 PM
Does an increase in SST after a storm suggest that warm Atlantic or Pacific waters have surfaced due to waves mixing the surface layer with deeper waters? If this is true, could continued high winds and 3 to 5 meter waves keep this mixing going and delay freeze even further?

Great question. I asked the same about 3 days ago upthread.
I keep thinking about the energy needed to melt ice cubes would heat the same amount of water to 80°C. So how much energy went into the ocean this summer with that GAAC and lots of open ocean?

And how long will it take to cool it all down again? I guess we're finding out now...
Title: Re: The 2020/2021 freezing season
Post by: uniquorn on October 19, 2020, 11:55:12 PM
For what is worth (not much, admittedly), but the surface analysis of GFS (the GDAS) did not show a significant drop for SST during the week-end. <>
Raw surface temperatures and drift from iabp buoys (https://iabp.apl.uw.edu/index.html) over the last 5 days. Drift speed is the coloured path with scale at top left, temperature as text label. (Buoys in ice should be reporting ice surface temperatures. NA means they do not report surface temperature, some may be faulty.)
Click twice for full res. Large file.
Title: Re: The 2020/2021 freezing season
Post by: A-Team on October 20, 2020, 12:17:58 AM
Quote
Effect of storms and high winds on freeze open water?
Whatever the actual effects, we are quite limited by available observables in terms of validation. As with the 2012 GAAC controversy, there is no control on what would have happened without the GAAC.

Consequently even if we had seen SST change here, attribution to the storm is problematic. Here the highest winds and swells did not hit the ice pack head on which has been required for major damage in the past. OsiSaf is showing a distinct anti-cyclonic rotation but has no motion coverage of open water (but see CMEMS).

The first image below maps out where it is currently cold enough to bring surface sea water to -1.8ºC. This would have to persist a very long time without wind to actually freeze anything. Here GFS nullschool doesn't offer SST contouring so it has to be done from a screenshot with wind turned off in Gimp GMIC, then labelled multiple times with green circle site data. A lot of the 'upper half' of the Arctic Ocean is just not cold enough yet.

The slide show looks at entrained Pacific Ocean moisture intrusion via total cloud water (TCW) which is determinable from satellite. The height of the cloud deck above the water surface is not available but presumably low; this property had to be measured during the Mosaic expedition.

This event brought in a gale force jet, matching the maximum the Polarstern encountered during its year. Moist low clouds can completely offset blackbody cooling of the surface but not evaporative, convective, conductive or mixing effects which potentially could be much larger.

Following moist intrusions into the Arctic using SHEBA observations in a Lagrangian perspective
S. Mubashshir Ali  Felix Pithan  19 June 2020
https://rmets.onlinelibrary.wiley.com/doi/full/10.1002/qj.3859 free full

"Warm and moist air masses are transported into the Arctic from lower latitudes throughout the year. Especially in winter, such moist intrusions (MIs) can trigger cloud formation and surface warming. While a typical cloudy state of the Arctic winter boundary layer has been linked to the advection of moist air masses, direct observations of the transformation from moist midlatitude to dry Arctic air are lacking.

Moist intrusions are usually triggered by an anticyclonic blocking‐like feature to the east and a low‐pressure system to the west and also linked to Rossby wave‐breaking events (Liu and Barnes, 2015). MIs cause strong downward long‐wave radiation due to a high localised concentration of water vapor which can lead to anomalous surface warming over land or sea ice."
Title: Re: The 2020/2021 freezing season
Post by: glennbuck on October 20, 2020, 12:56:15 AM
Where is the Emergency!

Title: Re: The 2020/2021 freezing season
Post by: Pavel on October 20, 2020, 06:42:23 AM
Too much heat stored. May, July, August were the warmest on record north of 70 latitude, June was the 2nd warmest, September the 3d warmest. We remember the GAAC and early ice retreat. It was really warm and not the all heat was spent to melt ice like in 2012 but rather stored in the ocean. If we compare with the 2016 autumn precondition now it looks much worse so the Arctic will have to dodge a cannonball once again in the melt season
Title: Re: The 2020/2021 freezing season
Post by: Aluminium on October 20, 2020, 08:37:15 AM
October 15-19.

2019 (https://forum.arctic-sea-ice.net/index.php/topic,2888.msg233556.html#msg233556).
Title: Re: The 2020/2021 freezing season
Post by: Paddy on October 20, 2020, 09:59:39 AM
The 3-day forecast is finally going below freezing on the Russian side of the Arctic, although still far above normal: https://climatereanalyzer.org/wx/fcst_outlook/?dm_id=arc-lea&nday=3-day

Title: Re: The 2020/2021 freezing season
Post by: Positive retroaction on October 20, 2020, 12:04:12 PM
also looking at the maximum temperatures over 5 days, maybe the pack ice will finally slowly start to spread first towards the new siberian islands, between kara and laptev
The maximum températures over 5 dans and SST for octobre 29 (forecast)
Title: Re: The 2020/2021 freezing season
Post by: Freegrass on October 20, 2020, 01:00:04 PM
October 15-19.

2019 (https://forum.arctic-sea-ice.net/index.php/topic,2888.msg233556.html#msg233556).
Last year the Northeast Passage was closing, and ice was forming along the Siberian coast.
That ain't happening yet this year, so the shipping industry must be very happy right now...
Title: Re: The 2020/2021 freezing season
Post by: gandul on October 20, 2020, 01:39:44 PM
October 15-19.

2019 (https://forum.arctic-sea-ice.net/index.php/topic,2888.msg233556.html#msg233556).

I see some hints of ice forming from the ESS/Laptev coast. Ice reaching from the coast while the ice edge is as far away as in September would be quite an spectacle.

Title: Re: The 2020/2021 freezing season
Post by: Freegrass on October 20, 2020, 01:45:26 PM
Latest Five Day Forecast
Wind @ Surface + Total Precipitable Water
Wind + Temp @ 850hPa
Wind @ 250hPa
Large GiFS!

The first really cold air is coming from Greenland...
Title: Re: The 2020/2021 freezing season
Post by: Positive retroaction on October 20, 2020, 01:45:57 PM
Yes
They probably are happy (sorry french Doc)
Title: Re: The 2020/2021 freezing season
Post by: Shared Humanity on October 20, 2020, 02:07:56 PM

The first really cold air is coming from Greenland...

While another strong low enters the Laptev.
Title: Re: The 2020/2021 freezing season
Post by: uniquorn on October 20, 2020, 02:20:05 PM
https://go.nasa.gov/3m5uQpn  oct15-20 with AWI AMSR2 v103 inset. The north greenland gap still recovering from the summer, sea ice still lifting off Ellesmere Island. Some Nares export.
Title: Re: The 2020/2021 freezing season
Post by: Freegrass on October 20, 2020, 02:27:56 PM

The first really cold air is coming from Greenland...

While another strong low enters the Laptev.
Yep... I looks like that's another burp from the jetstream, which still seems to be wanting to take a shortcut...
Title: Re: The 2020/2021 freezing season
Post by: Positive retroaction on October 20, 2020, 03:22:42 PM
Definitively, What we see in ESS laptev/kara is totaly new, reminds me example of the giant, global warming signs are exploding and will have consequences more and more
Title: Re: The 2020/2021 freezing season
Post by: Pagophilus on October 20, 2020, 05:03:39 PM
Definitively, What we see in ESS laptev/kara is totaly new, reminds me example of the giant, global warming signs are exploding and will have consequences more and more
The wider context is also troubling.  NOAA's report on this past September recently came out.

"Averaged as a whole, the September 2020 global land and ocean surface temperature was the highest for September in the 141-year record at 0.97°C (1.75°F) above the 20th century average of 15.0°C (59.0°F)."

https://www.ncdc.noaa.gov/sotc/global/202009
Title: Re: The 2020/2021 freezing season
Post by: Paul on October 20, 2020, 05:57:57 PM
The 3-day forecast is finally going below freezing on the Russian side of the Arctic, although still far above normal: https://climatereanalyzer.org/wx/fcst_outlook/?dm_id=arc-lea&nday=3-day

Sometimes we have to be careful looking at temperature maps in areas of open water as the models will always forecast higher temperatures whilst that open water is there. As far as I understand it, if ice did indeed grow in some of that open water area, the models will show slightly colder temperatures than first predicted. As it happens though, it seems difficult at this point too see much refreeze from the main pack but hopefully we will see more evidence of coastal ice forming with winds blowing in from the landmasses.
Title: Re: The 2020/2021 freezing season
Post by: BornFromTheVoid on October 20, 2020, 07:06:46 PM
Here's the chart showing the variations in the distance from ice edge/open water to the N. Pole for all the daily extent minima from 1979 to 2020 (measured every 5 degrees).
The trends largely resembles that of other measures:
2012 had the shortest average distance, at 944 km, followed by 2020 (991 km) and 2016 (1,060 km).
The 81-10 average is 1,328 km, and the maximum occurred in 1980 at 1,452 km.

There are some major limitations to this, especially looking at the minima for a single day when the ice edge may have reached closer to the N. Pole on days other than the minimum - but it's a start.

Anyway, I'll post some more regional data up tomorrow when I have more time.
Title: Re: The 2020/2021 freezing season
Post by: uniquorn on October 20, 2020, 09:05:31 PM
The 3-day forecast is finally going below freezing on the Russian side of the Arctic, although still far above normal: https://climatereanalyzer.org/wx/fcst_outlook/?dm_id=arc-lea&nday=3-day

Sometimes we have to be careful looking at temperature maps in areas of open water as the models will always forecast higher temperatures whilst that open water is there. As far as I understand it, if ice did indeed grow in some of that open water area, the models will show slightly colder temperatures than first predicted. As it happens though, it seems difficult at this point too see much refreeze from the main pack but hopefully we will see more evidence of coastal ice forming with winds blowing in from the landmasses.
There are some signs of light coastal refreeze along the esas. AMSR2 (awi v103) struggling to detect it consistently oct9-19, polarview S1 (http://polarview S1) showing more detail on oct19.
Title: Re: The 2020/2021 freezing season
Post by: A-Team on October 20, 2020, 10:04:12 PM
Quote
Too much heat stored. May, July, August were the warmest on record north of 70 latitude, June was the 2nd warmest, September the 3d warmest.
Plus too much summer sunshine on low albedo open water in addition to longer term trend marine preconditioning.

Coastal landfast ice ... forget it. It was a big deal 30-40 years ago. It will not grow out significantly and certainly not meet up with the main ice pack. Ice grows primarily all around the periphery of the main ice pack. There's a reason for that: it's colder next to a lateral wall of ice (Fig.1). The ice pack will grow up towards the ESS, eventually separating the Laptev waters from the Chukchi (which will be the very last to freeze, early January).

The second figure adds the ice pack to uniq's Laptev active temperature sensors and deletes the non-reporting devices leaving 6 instruments (plus a few weather stations) reporting on millions of sq km of open water. Too bad the Polarstern had to go in. The Arctic basin is currently 39.8% open water by pixel count.

Revisiting @zlabe's Laptev records, at this point 2020 does not resemble previous record years at all so a new record date is likely, perhaps 2-3 weeks beyond the previous latest freeze-up (Nov 6th).

Looking now at the last 18 days of thickening of new ice at the pack edge with SMOS-SMAP (which can only measure 0.0 to 0.5 m thickness), it's not all that clear how rapidly thickness is progressing to the cutoff (tan color) because cycling winds are moving features around on a daily basis per OsiSaf. Click to animate.
Title: Re: The 2020/2021 freezing season
Post by: Freegrass on October 20, 2020, 10:41:14 PM
Quote
Too much heat stored. May, July, August were the warmest on record north of 70 latitude, June was the 2nd warmest, September the 3d warmest.
Plus too much summer sunshine on low albedo open water in addition to longer term trend marine preconditioning.

Coastal landfast ice ... forget it. It was a big deal 30-40 years ago. It will not grow out significantly and certainly not meet up with the main ice pack. Ice grows primarily all around the periphery of the main ice pack. There's a reason for that: it's colder next to a lateral wall of ice (Fig.1). The ice pack will grow up towards the ESS, eventually separating the Laptev waters from the Chukchi (which will be the very last to freeze, early January).<snip>
Do you think that when the heat from the arctic deep starts keeping the Arctic Ocean open that the only ice we'll see will be located at the shores, where it is more shallow?
Title: Re: The 2020/2021 freezing season
Post by: pearscot on October 20, 2020, 10:56:29 PM
This refreeze season is just so strange! It's weird how things are somewhat 'normal' on the North American side (not sure what normal even is anymore), but the amount of open water this late in the year is pretty wild. There's no way to know without measuring it, but I suspect the extra warmth this summer on the Siberian side did increase evaporation in conjunction with intense late-season winds only help the further weaken the halocline layer.

I'm sure most of the major areas of the Arctic will refreeze prior to the start of the 2021 melt season, but it's impossible for me to guess what kind of impact such a late start will have. That said, if there are a few areas which remain open throughout the winter I think that will have some profound effects going forward. 
Title: Re: The 2020/2021 freezing season
Post by: kassy on October 20, 2020, 11:43:52 PM
It´s not that strange. A couple of years back it was warmer at the north pole then in London.
I really see this just as a logical progression.
Title: Re: The 2020/2021 freezing season
Post by: Freegrass on October 21, 2020, 12:19:18 AM
I didn't see this posted here yet...
Title: Re: The 2020/2021 freezing season
Post by: ArcTickTock on October 21, 2020, 04:14:02 AM
I have to agree with Pearscot, it is strange.  Strange that many of us were predicting that all the open ocean so early in the melting season, particularly in the Laptev, would result in a lot of heat being captured in Arctic waters resulting in a late freeze up, and then this actually happened!  After watching the Arctic a number of years you get sort of used to seeing the system defy short term expectations.

Seriously though, this is looking a bit different as we are setting new unfortunate records daily again and definitely an ill portent if it continues much longer.
Title: Re: The 2020/2021 freezing season
Post by: peterlvmeng on October 21, 2020, 06:02:30 AM
I agree. Late freezing season is a definitive event in the future year. Those only focus on the year maximum and minimum sea ice extent value cannot see the whole thing.
Title: Re: The 2020/2021 freezing season
Post by: jens on October 21, 2020, 09:43:02 AM
In terms of daily ice gains second half of October and early November should be peak refreezing days. It looks like this peak is being postponed further down the road. Either that or refreezing will just smoothen out over a longer period.

Year 2020 was a slow starter due to cold winter, but since then it has been building up strongly and looks like we are reaching culmination late in the year, already after the melting season. Now 1M km2 advantage over 3rd place. How much bigger can it get?
Title: Re: The 2020/2021 freezing season
Post by: uniquorn on October 21, 2020, 11:57:41 AM
NSIDC ease-grid ice sea age update. The nearest clear day I found on Worldview for comparison in the Beaufort was oct8. https://go.nasa.gov/2IITyxk
click for animation.
edit: 2000-2020 animation here (https://forum.arctic-sea-ice.net/index.php/topic,2417.msg271199.html#msg271199)
Title: Re: The 2020/2021 freezing season
Post by: Freegrass on October 21, 2020, 02:26:32 PM
Latest Five Day Forecast
Wind + Temp @ Surface
Large GiF!
Title: Re: The 2020/2021 freezing season
Post by: A-Team on October 21, 2020, 02:31:10 PM
The Oct 6th sea ice age view of first year ice can be updated to Oct 20th. NSIDC defines graduation day as Sept 15th for consistency regardless of the actual minimum. The image below subtracts the two dates, the difference being the new ice to date (not allowing for ice displacement). Almost all the FYI is in the 'lower half' some 35 days in to the freezing season, unlike 2019 etc.

Climate reanalyzer does not foresee 2m temperatures dropping too much over the next ten days. Because some colors are dithered (for print!?!), the correspondence with the color bar is poor. Accurate tick marks cannot be put on the color bar because its pixel width is not an integral multiple of degrees. These errors degrade expensively acquired data so need to be fixed.

Roughly then, the contour range is a degree or two above and a few below 0ºC in the 'upper half', not enough for seawater to freeze (selected areas on color bar, lower left). The anomaly is relative to 1979-2000 so, given Arctic Amplification, is quite pronounced.

https://climatereanalyzer.org/wx/fcst_outlook/?dm_id=arc-lea&nday=10-day
Title: Re: The 2020/2021 freezing season
Post by: Shared Humanity on October 21, 2020, 02:33:34 PM
Amazing how these lows traversing the Siberian and Pacific side of the basin are preventing any real deep freeze surface temperatures from setting up where we currently have open water. They are even delivering relatively warm temperatures over the ice edges. Contrast this with the very low surface temps north of Greenland.

Are we seeing rough seas in the open waters?
Title: Re: The 2020/2021 freezing season
Post by: binntho on October 21, 2020, 02:41:00 PM
It feels a bit like a battle between two major powers the "Oceanic Republic" and the "Continental Empire". Normally at this time of year, the Arctic would be fast slipping under the control of the latter, along with Siberia, firmly establishing a contintental climate.

But this year the Republic is fighting a tenuous rearguard action, keeping millions of km2 under  an oceanic climate for the first time in recent memory.

We all seem to agree that the Empire will win this battle eventually, at least this winter, but what about next year? What happens when an oceanic climate manages to keep it's hold of the Siberian coastline throughout winter? The effects on the permafrost hardly bear thinking about, let alone the knock-on effects on weather all over the place.
Title: Re: The 2020/2021 freezing season
Post by: BornFromTheVoid on October 21, 2020, 03:08:30 PM
Records continue to tumble.
Now the slowest October increase to the 20th, lowest on record by 455k, largest -ve anomaly on record at 3.396 million km2 and almost 4 million km2 below the average of the 1980s
Title: Re: The 2020/2021 freezing season
Post by: FishOutofWater on October 21, 2020, 03:28:25 PM
The ice on the Eurasian side of the N pole is slightly greater than 1 meter thick according to Russian reports. They just sent a new icebreaker to the pole to test its performance but the ice was too thin to test it. They hoped to find some 3 m thick ice but icebreaker went to the pole unhindered by any thick ice. From the Barents Observer
 https://thebarentsobserver.com/en/arctic/2020/10/north-pole-ice-cap-too-thin-testing-russias-giant-icebreaker

 “Ice tests are still ahead, probably this year, because now ice tests did not work out, the ice thickness was 1,1 to 1,2 meters. It was thin and loose, the icebreaker received no resistance at all,” Shchapin says.

He adds: “We tried to find a three-meters ice floe, but they did not find it.”
Title: Re: The 2020/2021 freezing season
Post by: Shared Humanity on October 21, 2020, 03:46:35 PM
Fragmented, one meter thick ice all the way to the North Pole!
Title: Re: The 2020/2021 freezing season
Post by: Général de GuerreLasse on October 21, 2020, 04:09:48 PM
The ice on the Eurasian side of the N pole is slightly greater than 1 meter thick according to Russian reports. They just sent a new icebreaker to the pole to test its performance but the ice was too thin to test it. They hoped to find some 3 m thick ice but icebreaker went to the pole unhindered by any thick ice. From the Barents Observer
 https://thebarentsobserver.com/en/arctic/2020/10/north-pole-ice-cap-too-thin-testing-russias-giant-icebreaker

 “Ice tests are still ahead, probably this year, because now ice tests did not work out, the ice thickness was 1,1 to 1,2 meters. It was thin and loose, the icebreaker received no resistance at all,” Shchapin says.

He adds: “We tried to find a three-meters ice floe, but they did not find it.”

The Canadian and Greenlandic comrades could have allowed the Russian comrades to sail in their territorial waters to test their new toy. Perhaps the size of future icebreakers should be reduced. 8)
Title: Re: The 2020/2021 freezing season
Post by: aslan on October 21, 2020, 06:39:45 PM
After the storm of this mid October I was also wondering myself what are the consequences of the open water on synoptic forcings for ascent. As a remainder, vertical velocity are stronger for a same forcing with lower static stability. I don't know if there is studies about this subject, or if it is a significant effect, but it is an open question for me. This is probably linked to the displacement of the eddy driven jet, but I am not aware of any study really looking specifically at the consequences of this reduced static stability. This is also leading to higher wind speed at surface, as seen with the last storm. On top of that, strong inversion over ice pack, and now over the continent, is on juxtaposition of this low static stability, leading to increased baroclinic instability. But what is the magnitude of this effect ? I am really clueless. To illustrate, I have compute a crude static stability parameter, by subtracting potential temperature at 700 hPa and at 950 hPa, normalized by the thickness 700 - 950 hPa. All of this multiplied by 10 to better seen what is going on. Below 0, the atmosphere is superadiabatic, and everything above is subadiabatic. Over mountains (like, said, the Rockies...), results are of course useless, as the model interpolate trough the terrain. Maps are for, in order, the 21st to the 24th at 00Z. Didn't try to average trough time, the computer would probably have hoist the white flag before the end... We can see a persistent area of low stability over the Siberian seas.
Title: Re: The 2020/2021 freezing season
Post by: bbr2315 on October 21, 2020, 08:29:59 PM
There is going to be an imminent start to the refreeze in Hudson Bay and Foxe Basin, some of the shorelines are now seeing ice develop, this will be ahead of most recent years and could mask the continued horrible state of the Laptev, ESS, Kara, Bering. Bering is WARM.

In fact the entire cryosphere is now showing signs of being lobbed into two, as visible in Sark's thread. While the overall numbers are down as a whole they are concentrated in the Eurasian-adjacent sea ice and Eurasia itself, the positives are being made up in CAA, North American snowcover, and imminently, Hudson Bay / Foxe Basin.

Why is the cyrosphere splitting into two most consistently these days? Look at the maps! Thank you Nicosun for the fantastic maps, btw.

(https://drive.google.com/uc?id=1I-FJQFBMm_u88NpLT_pk96RsJ6f_pN5f&export=download)

(https://drive.google.com/uc?id=1WmpWVrVyk3oYqAezG3c16lPq-jyJpvSx&export=download)

I think this portends the worst-ever refreeze of the Arctic Basin itself. But potentially weird situations like an abundance of ice in random lower latitude locations east of Canada and Greenland and maybe Okhotsk.
Title: Re: The 2020/2021 freezing season
Post by: Pagophilus on October 22, 2020, 03:36:28 AM
Ice obediently trying to follow the "First, you must cover the Arctic Basin, and only then the Siberian Seas" rule.              Oct 20, 2020.   https://oden.geo.su.se/map/

If the early summer melt over the Laptev corner of the Arctic Basin is any indication, there may be late refreezing over that area of the basin.
Title: Re: The 2020/2021 freezing season
Post by: mabarnes on October 22, 2020, 04:56:35 AM
Hey question for anybody who knows more than I about this stuff:

AKA everybody LOL.

So GFS shows a low pressure spinning out over the ESS next few days - is this going to be (my attempt) rising air, convection upward, more heat out to space, maybe venting some of it off ... or the opposite?  Or something totally different?

Trying to build a framework here.  Anybody with insomnia want a detailed lesson on economic analysis using multivariate systems, I'll return the favor! 
Title: Re: The 2020/2021 freezing season
Post by: El Cid on October 22, 2020, 07:31:26 AM
I know nothing, but I'd say that low pressure = clouds = less heat out into space. Aint it so?
Title: Re: The 2020/2021 freezing season
Post by: Aluminium on October 22, 2020, 11:34:18 AM
October 17-21.

2019 (https://forum.arctic-sea-ice.net/index.php/topic,2888.msg233765.html#msg233765).
Title: Re: The 2020/2021 freezing season
Post by: gerontocrat on October 22, 2020, 01:00:13 PM
You read all about it first on the Arctic Sea Ice Forum....

https://www.theguardian.com/world/2020/oct/22/alarm-as-arctic-sea-ice-not-yet-freezing-at-latest-date-on-record
Alarm as Arctic sea ice not yet freezing at latest date on record
Delayed freeze in Laptev Sea could have knock-on effects across polar region, scientists say

Quote
For the first time since records began, the main nursery of Arctic sea ice in Siberia has yet to start freezing in late October.

The delayed annual freeze in the Laptev Sea has been caused by freakishly protracted warmth in northern Russia and the intrusion of Atlantic waters, say climate scientists who warn of possible knock-on effects across the polar region.

Ocean temperatures in the area recently climbed to more than 5C above average, following a record breaking heatwave and the unusually early decline of last winter’s sea ice.

The trapped heat takes a long time to dissipate into the atmosphere, even at this time of the year when the sun creeps above the horizon for little more than an hour or two each day.

Graphs of sea-ice extent in the Laptev Sea, which usually show a healthy seasonal pulse, appear to have flat-lined. As a result, there is a record amount of open sea in the Arctic.

“The lack of freeze-up so far this fall is unprecedented in the Siberian Arctic region,” said Zachary Labe, a postdoctoral researcher at Colorado State University. He says this is in line with the expected impact of human-driven climate change.

“2020 is another year that is consistent with a rapidly changing Arctic. Without a systematic reduction in greenhouse gases, the likelihood of our first ‘ice-free’ summer will continue to increase by the mid-21st century,’ he wrote in an email to the Guardian.

This year’s Siberian heatwave was made at least 600 times more likely by industrial and agricultural emissions, according to an earlier study.

The warmer air temperature is not the only factor slowing the formation of ice. Climate change is also pushing more balmy Atlantic currents into the Arctic and breaking up the usual stratification between warm deep waters and the cool surface. This also makes it difficult for ice to form.

“This continues a streak of very low extents. The last 14 years, 2007 to 2020, are the lowest 14 years in the satellite record starting in 1979,” said Walt Meier, senior research scientist at the US National Snow and Ice Data Center. He said much of the old ice in the Arctic is now disappearing, leaving thinner seasonal ice. Overall the average thickness is half what it was in the 1980s. The downward trend is likely to continue until the Arctic has its first ice-free summer, said Meier. The data and models suggest this will occur between 2030 and 2050. “It’s a matter of when, not if,” he added.

Scientists are concerned the delayed freeze could amplify feedbacks that accelerate the decline of the ice cap. It is already well known that a smaller ice sheet means less of a white area to reflect the sun’s heat back into space. But this is not the only reason the Arctic is warming more than twice as fast as the global average.

The Laptev Sea is known as the birthplace of ice, which forms along the coast there in early winter, then drifts westward carrying nutrients across the Arctic, before breaking up in the spring in the Fram Strait between Greenland and Svalbard. If ice forms late in the Laptev, it will be thinner and thus more likely to melt before it reaches the Fram Strait. This could mean fewer nutrients for Arctic plankton, which will then have a reduced capacity to draw down carbon dioxide from the atmosphere.

More open sea also means more turbulence in the upper layer of the Arctic ocean, which draws up more warm water from the depths.

Dr Stefan Hendricks, a sea ice physics specialist at the Alfred Wegener Institute, said the sea ice trends are grim but not surprising. “It is more frustrating than shocking. This has been forecast for a long time, but there has been little substantial response by decision-makers.”
Title: Re: The 2020/2021 freezing season
Post by: grixm on October 22, 2020, 01:01:17 PM
October 17-21.

2019 (https://forum.arctic-sea-ice.net/index.php/topic,2888.msg233765.html#msg233765).

Looks like the freeze is finally getting started in various Laptev and Kara river outlets.
Title: Re: The 2020/2021 freezing season
Post by: Shared Humanity on October 22, 2020, 02:15:49 PM
Ice obediently trying to follow the "First, you must cover the Arctic Basin, and only then the Siberian Seas" rule.              Oct 20, 2020.   https://oden.geo.su.se/map/

If the early summer melt over the Laptev corner of the Arctic Basin is any indication, there may be late refreezing over that area of the basin.

You look to be right.

gerontocrat posts data and charts daily on the Sea Ice Extent and Area thread. I make a habit of visiting that thread daily. I brought this one over as an example. Laptev is entering a very scary place. Still possible for it to freeze over rapidly. Last 9 days of October are going to be interesting. Let's hope we don't flatline for the remainder of the month.
Title: Re: The 2020/2021 freezing season
Post by: Freegrass on October 22, 2020, 03:52:18 PM
Latest Five Day Forecast
Wind @ Surface + Total Precipitable Water
Wind + Temp @ 850hPa
Large GiFS!
Title: Re: The 2020/2021 freezing season
Post by: Freegrass on October 22, 2020, 04:01:48 PM
The flute playing mouse is getting its ass sucked into the Beaufort Sea...
Title: Re: The 2020/2021 freezing season
Post by: wili on October 22, 2020, 04:40:50 PM
(That's not a sentence that has ever been written before, I'm guessing! :) )
Title: Re: The 2020/2021 freezing season
Post by: Freegrass on October 22, 2020, 04:59:21 PM
(That's not a sentence that has ever been written before, I'm guessing! :) )
;D ;D ;D
And a good thing I used "into" instead of "in"...  ::)
Title: Re: The 2020/2021 freezing season
Post by: Glen Koehler on October 22, 2020, 05:24:34 PM
Once the water is back to to freezing, the ice will form at the same sort of rates, but it'll be a few days later than in the past...
I'd say it will be a faster refreeze as the surrounding air and the continents will be much colder by then than during previous refreezes. Late but fast refreeze. We shall see
      The Guardian article mentions a possible ecological impact on nutrient transfer from the delayed Laptev Sea refreeze.  It seems likely that once refreeze begins it will be more rapid than "normal" because it will be occurring at a later date.  That makes me wonder if the rate of Arctic Ocean refreeze has important but little-discussed impacts.  If the ice pack edge advances many more miles per day than normal, how does that affect the microscopic and macroscopic organism communities that interact with the water/ice environment?

       Ice vs. water is a major habitat change, and the rate at which that habitat shift occurs could have consequences.  While I doubt that ice-edge advance is going to be so fast as to outrun the ability of air-breathing marine mammals that need access to open water to relocate, that's an extreme (though I think implausible) example of the kind of scenario that comes to mind.  What seems more likely is some effect on the colonization, population growth rate, and niche partitioning of microflora/fauna on newly formed ice.  For example, it may make a difference to community structure if there only 3 versus 30 days between initial colonization and the date when discriminating environmental conditions occur. 

       The relative timing of such events may have trivial consequences, or it may not.  Small differences over such a large scale can have a large impact, especially in a tightly linked system where each domino affects all the following dominoes.  Even though Extent / Area / Thickness / Volume will probably return to closer to the normal range quickly once refreezing begins, even getting back to a closer match with "normal" values after a late refreeze start and rapid rebound may bring with it subtle but significant qualitative physical, chemical, biological and/or behavioral differences that are not apparent from the quantitative Ex / Ar / Th / Vol measurements. 

       The fact that the Russians could not really test their new ice breaker on a run to the North Pole because the ice was too thin and broken is not an Earth-shaking consequence, but it exemplifies how changes ripple through a system in unforeseen ways.  Everything is connected.  I do not expect obvious or catastrophic impacts, but the potential effects of refreeze timing and rate do seem worth noting.  I wonder if/how Arctic scientists are tracking such potential qualitative impacts.
Title: Re: The 2020/2021 freezing season
Post by: BornFromTheVoid on October 22, 2020, 05:32:43 PM
Animation of the extent and distribution of ice for October 21st.
(Click to play)
Title: Re: The 2020/2021 freezing season
Post by: mabarnes on October 22, 2020, 07:07:20 PM
I know nothing, but I'd say that low pressure = clouds = less heat out into space. Aint it so?

Hey thank you for the response.  I was wondering about that - but I read something about tropical storms in the Pacific and convection transferring warmer (moist) air up to where it can radiate out from there ... I would figure the Arctic may be different as it's so much colder (Scoop! LOL) and maybe the clouds formed block IR from the sea surface ... geez Louise this weather thing can get complicated....

I'm really curious about this stuff so again, thank you.

Title: Re: The 2020/2021 freezing season
Post by: UCMiami on October 22, 2020, 07:37:32 PM
I don't know that there is any data on when the change over in 'net' bottom melt to 'net' bottom growth of ice has occurred historically because it is hidden from easy observation and is likely to be extremely dynamic on a very local basis, but extent growth (rapid or slow) in itself is not as important as growth in thickness to the long term state of arctic ice.

What is clear is that in order for ice to thicken there has to be ice to start with (duh!)

What I am trying to bring up is that extent by itself is only an indication of when ice thickening can possibly begin, and with the current extreme delay in the Asian sea ice extent, the ice growth in thickness is being delayed. While historically some areas of the Asian seas have had slow growth in extent, 2020 is the first year on record (as far as I know) that will likely still have an ice free NE passage on Nov 1. (And not just dodging ice, but wide a open sea lane.) The fear is that if this continues much longer even with eventual universal 100% extent on the Asian side, that first year ice will not have a chance for a 'normal' gain in thickness. Instead of >1M ice, much of the Asian sea ice could end the freezing season in a very fragile state leading to much earlier breakup and melt in 2021. Already basically the whole of the Asian side has lost a month of thickness growth, where in previous years a fairly large percentage of those seas had already started that growth.

And the fact that salinity/warmth incursion of Atlantic waters may eventually be counteracted by night and cold weather that allows the 'normal ice extent' in these seas, the effects of increased warmth and salinity will probably continue to retard the 'normal' sea ice thickening of that late extent.
Title: Re: The 2020/2021 freezing season
Post by: Shared Humanity on October 22, 2020, 08:16:27 PM
I know nothing, but I'd say that low pressure = clouds = less heat out into space. Aint it so?

Hey thank you for the response.  I was wondering about that - but I read something about tropical storms in the Pacific and convection transferring warmer (moist) air up to where it can radiate out from there ... I would figure the Arctic may be different as it's so much colder (Scoop! LOL) and maybe the clouds formed block IR from the sea surface ... geez Louise this weather thing can get complicated....

I'm really curious about this stuff so again, thank you.

H2O is a powerful greenhouse gas...there is a reason deserts cool off so rapidly at night.
Title: Re: The 2020/2021 freezing season
Post by: HapHazard on October 22, 2020, 09:12:29 PM
Freezing season 2020/21

Siberian Seas "Ice Thickening Days" running total = 0
Title: Re: The 2020/2021 freezing season
Post by: Pagophilus on October 22, 2020, 09:13:19 PM
The flute playing mouse is getting its ass sucked into the Beaufort Sea...
I shall never look at the Arctic in quite the same way again.
Title: Re: The 2020/2021 freezing season
Post by: A-Team on October 22, 2020, 09:16:22 PM
Quote
runaway feedbacK? much of Siberian side sea ice could end the freezing season in a very fragile state leading to earlier breakup and melt in 2021. A few days weeks late then catch-up with really fast refreeze (even though graphs of past years don't show this behavior)?
The SST will be nowhere near freezing by the end of the month; indeed air temperatures at -3 aren't cold enough to even move the needle. It takes much deeper longer cold to lower water temperature from +1ºC enough to set the stage at -1.8º for a flash freeze especially if the upper 10m of water is in play (not talking here about a micron at the surface).

The weather system over the next 120 hrs will be bringing in a fair amount of TCW (total cloud water). This again is not conducive to radiative cooling.

I'm wondering if the TransPolar Drift will set up late or perhaps hardly at all. This amount and location of open water heat may feed back on the atmospheric pressure pattern to some extent, undercutting what is needed for persistent TPD winds. If so, export out the Fram would be diminished, mostly to what ice is in the intake funnel now.

Alternatively, since Fram export stopped back in mid-May along with no garlic press and only a quarter turn Beaufort Gyre, something at a much larger atmospheric scale has changed, with late open water only having a secondary effect.

Where is nullschool getting its SST and TCW values from or rather, are there other sources that might be better or at least independent? Hard to say: multiple sources are listed for SST; none for TCW! The latter may be derived from Band 7 (2.1 μm) on Modis where it is called Cloud Water Path at WorldView
Title: Re: The 2020/2021 freezing season
Post by: Tor Bejnar on October 22, 2020, 09:24:06 PM
Does anybody follow the freezing-degree-days data?  (by region would be useful) 
Title: Re: The 2020/2021 freezing season
Post by: pearscot on October 22, 2020, 09:58:39 PM
It's so weird to me seeing both this wave action and zero ice (but with snow on the ground) this late in October in Barrow (so glad the camera is up and running again).

I'm just so curious as to what weather/ice formation effects the Siberian side will have. Ice will form, but I think it's going to be more fragile/mobile than ever.

Title: Re: The 2020/2021 freezing season
Post by: A-Team on October 22, 2020, 10:26:06 PM
Quote
freezing-degree-days? by region
Would it be easier and more informative just to query nullschool very three hours for the next five days at a handful of representative locations? Or drop a time series of screenshots onto a contouring tool? FDD is not likely to have the correct freezing temperature for the given surface salinity nor current open water as a region nor go forward in time. It's the kind of thing you would see with associated with the 80ºN DMI graph. Why, when 2m ave temperature maps are readily available?

http://psc.apl.washington.edu/nonwp_projects/landfast_ice/freezing.php
Title: Re: The 2020/2021 freezing season
Post by: Glen Koehler on October 22, 2020, 10:27:48 PM
Climate reanalyzer does not foresee 2m temperatures dropping too much over the next ten days. Because some colors are dithered (for print!?!), the correspondence with the color bar is poor. Accurate tick marks cannot be put on the color bar because its pixel width is not an integral multiple of degrees. These errors degrade expensively acquired data so need to be fixed.
     The brain and 10 nimble fingers that singlehandedly (correction: 10 fingers = 2 hands) operates Climate Reanalyzer is aware of your critique.  The reason for dithering the color scales is because for the weather forecast animations it reduces file download size by a factor of 6X.  The file sizes are not so large as to matter for folks on an unlimited-data high-speed connection, but for people on a slower (or data-metered) connection (DSL was mentioned as a slower connection, and smartphone internet is an example of a metered connection), the file size does matter. 

    That person also mentioned that for stand-alone images, dithering the color scale may not be necessary so a possible change will be investigated.  Suggestions are well received, just remember that while CR may look like some well-funded institutionalized juggernaut, it really is a part-time operation by one person with a vision, programming skill, and committment who built something nobody else (including well-funded institutionalized juggernauts) had gotten around to doing, and done while juggling multiple other responsibilities and deadlines, including a recurring requirement for periods away from the keyboard to eat, sleep and other aspects of life.
Title: Re: The 2020/2021 freezing season
Post by: A-Team on October 22, 2020, 11:28:57 PM
Climate Reanalyzer is very popular and deservedly so! Indeed I thought it was a large institutional project with bloated govt grants and large indifferent staff.

In terms of colors, keeping to small file size, faithful gif animation frames vs vastly smaller mp4, and importantly allowing values from the map to be read off on the palette (respectively selecting all map colors for a given value range), viewer expectations have been going up as they see examples elsewhere where someone got it all going. The wheel has been invented, let's get it rolling.

What I would recommend here is just copying the methods of L Kaleschke at AWI in producing what we've been discussing as AMSR2_AWI. Here the number of discrete colors is strictly clamped to 102 though 8-bit gif has room for 256. That is plenty. There is never a need for the 16.7 million colors of 24-bit color except with photography. Here we want binned colors. It is actually quite hard to find a set of even 20 related but distinguishable colors (for maximally unrelated, glassby).

With the AMSR2 there are no lossy jpg compressions, dithering for print, sq root two rotations of 45º to standard 'Greenland down' orientation of satellite data. The file size is merely 567 kB for 2432 x 3584 pixels. Plus it is internally geo-referenced so converts to netCDF/Panoply which people want for numeric array work. Plus viewers can easily highlight selected portions of the palette or easily replace it with the thousands of LUTs at ImageJ or even one they specify from scratch.

Three more easy suggestions, seldom seen together: use the standard 3413 EPSG WGS-84 stereographic projection for the Arctic, specify the scale (pixel count out to special latitude of 70ºM), and provide the land mask. The isolationism we have now is an incredible waste of everyone's time; climate change above all needs data integration from disparate sources. Maps aren't pictures, they're working data.

While inclusivity (rotary dial-up, pay per MB) is laudable, it is just not the present much less the future for the 99% who might have an interest in climate reanalysis. At some point, it is not possible to cater to the very lowest devices nor assume everyone is on campus but better to find a middle ground lest the more typical users be constantly punished.

ftp://ftp.awi.de/sea_ice/product/amsr2/v103/nh/2020/10/
Title: Re: The 2020/2021 freezing season
Post by: Glen Koehler on October 22, 2020, 11:50:23 PM
     I'll pass those comments along.  Out of my league to make any comment.
Title: Re: The 2020/2021 freezing season
Post by: Niall Dollard on October 23, 2020, 12:14:00 AM
Does anybody follow the freezing-degree-days data?  (by region would be useful)

Alaska FDD data here : https://www.weather.gov/aprfc/FreezingDegreeDays

Mostly below normal, but early days. Some interior parts (eg Fairbanks) are above normal

And Nico Sun's FDD charts using the DMI 2m 80N+ data  :

https://sites.google.com/site/cryospherecomputing/fdd

Title: Re: The 2020/2021 freezing season
Post by: Tor Bejnar on October 23, 2020, 12:28:46 AM
Thanks, Niall.  I was looking at the DMI 80N chart (shame on me...) and it looked like it might be showing record 'minimized cooling'.  I was hoping somebody knew more than I.
Title: Re: The 2020/2021 freezing season
Post by: aslan on October 23, 2020, 08:41:20 AM
What I am trying to bring up is that extent by itself is only an indication of when ice thickening can possibly begin, and with the current extreme delay in the Asian sea ice extent, the ice growth in thickness is being delayed. While historically some areas of the Asian seas have had slow growth in extent, 2020 is the first year on record (as far as I know) that will likely still have an ice free NE passage on Nov 1. (And not just dodging ice, but wide a open sea lane.) The fear is that if this continues much longer even with eventual universal 100% extent on the Asian side, that first year ice will not have a chance for a 'normal' gain in thickness. Instead of >1M ice, much of the Asian sea ice could end the freezing season in a very fragile state leading to much earlier breakup and melt in 2021. Already basically the whole of the Asian side has lost a month of thickness growth, where in previous years a fairly large percentage of those seas had already started that growth.

It is a rough estimate, but if you use the correlation of Freezing Degrees Day (FDD) with ice thickness, you need ~5500 FDD to go to 2m first year ice, and ~3500 FDD to go to 1.5 meters. October is usually worth ~300 to ~400 FDD in the Arctic, so it can make a significant dent into the ice growth.
To give some more numbers, for Ostrov kotel'nyj for example. Mean temperature from 1st of October to 30th of April over the last 10 years (2010-2019) was -20.8°C, which is about 4400 - 4500 FDD. If you count from the 1st of November, this leads to 4100 - 4200 FDD. And if you ignore November and start the ice thickening the 1st of December, it makes only 3800 - 3900 FDD. This is ignoring the risk that oceanic heat flux could be strong enough this winter to weaken this correlation. If ice growth does not start in a hurry on the Siberian side, the winter would probably not be able to fully erase the memory of this melting season. Which is a great peril, as up to the last years, winter was always cold and long enough to at least bring Arctic back to some kind of a "2m FYI" state, helping to stabilize the system.
Title: Re: The 2020/2021 freezing season
Post by: Sepp on October 23, 2020, 09:09:05 AM
It is a rough estimate, but if you use the correlation of Freezing Degrees Day (FDD) with ice thickness, you need ~5500 FDD to go to 2m first year ice, and ~3500 FDD to go to 1.5 meters. October is usually worth ~300 to ~400 FDD in the Arctic, so it can make a significant dent into the ice growth. [...]

Wow, thank you, this was pretty much exactly the information I was wondering if it existed in such condensed form. :)
Title: Re: The 2020/2021 freezing season
Post by: blu_ice on October 23, 2020, 09:59:06 AM
[ADS NIPR VISHOP (JAXA)] Arctic Sea Ice Extent.

On the following days, 2019 is going to have several increases of more than 200K km2. As a result, on October 27th, the year 2016 starts having the lead as the lowest on record.

For 2020 to have a difference of less than one million km2 versus 2016, 2020 needs to have an average increase of more than 112.5K km2 until August 27.

Will 2020 have this average increase? If it does not have it, then on August 27th, the year 2020 will be more than one million km2 lower than any other year on record.
My guess is that on Oct 27th 2020 will have it's biggest lead. If not, this will get very interesting indeed.
Title: Re: The 2020/2021 freezing season
Post by: gandul on October 23, 2020, 11:12:33 AM
It is a rough estimate, but if you use the correlation of Freezing Degrees Day (FDD) with ice thickness, you need ~5500 FDD to go to 2m first year ice, and ~3500 FDD to go to 1.5 meters. October is usually worth ~300 to ~400 FDD in the Arctic, so it can make a significant dent into the ice growth.
To give some more numbers, for Ostrov kotel'nyj for example. Mean temperature from 1st of October to 30th of April over the last 10 years (2010-2019) was -20.8°C, which is about 4400 - 4500 FDD. If you count from the 1st of November, this leads to 4100 - 4200 FDD. And if you ignore November and start the ice thickening the 1st of December, it makes only 3800 - 3900 FDD. This is ignoring the risk that oceanic heat flux could be strong enough this winter to weaken this correlation. If ice growth does not start in a hurry on the Siberian side, the winter would probably not be able to fully erase the memory of this melting season. Which is a great peril, as up to the last years, winter was always cold and long enough to at least bring Arctic back to some kind of a "2m FYI" state, helping to stabilize the system.

Have you seen the snow extent growth over Siberia and Western Canada? Anything to comment or you only rejoice on the bad feedbacks?

https://www.ccin.ca/index.php/ccw/snow/current

Apart from this, the weather is about to become propitious for a quick rebound of sea ice next week.
Title: Re: The 2020/2021 freezing season
Post by: A-Team on October 23, 2020, 11:28:25 AM
Quote
up to the last years, winter was always cold and long enough to at least bring Arctic back to some kind of a "2m FYI" state
Good way of putting it. The 'last years' might be worth an extra look given what the Polarstern and its buoys observed for ice thickness growth. Here the FDD kelvin air temperature and oceanic heat flux have to drift thousands of km with the floe under TPD rather than stay at Kotelny Island. The TPD has yet to take shape this fall; there's no Laptev ice yet to push towards the Fram.

The rate of ice thickening is initially fast but it falls off in proportion to its attained thickness per the heat equation as it approaches 2m. This means it can largely make up for a late start and catch up to "2m FYI" but this ice differs greatly in the extent of maturation (mechanical strength, brine exclusion, ridging, snow accumulation pattern, melt pond susceptibility) from ice that begins forming in early October.

There's been no indication in recent days of the ice pack front advancing towards the Siberian side nor spot ocean temperatures there going negative much less approaching the -1.8ºC freezing point. The lobe approaching the ESS/eastern Laptev will be the first to freeze as it is -0.3ºC now and following historical precedent. The Chukchi is currently at +3.5ºC so some will probably stay open into mid-January.
Title: Re: The 2020/2021 freezing season
Post by: SimonF92 on October 23, 2020, 11:34:19 AM
A-Team, that visualisation is much more detailed than other SST resources and hence very useful (so thank you) but the discrete colour bins don't feel intuitive- if it isn't too much effort I think a Temps legend would be useful. Its hard to determine the range etc.
Title: Re: The 2020/2021 freezing season
Post by: A-Team on October 23, 2020, 12:04:03 PM
Quote
temperature labels would be useful on the above graphic
The purple is -1.8ºC under the ice pack and it goes up from there in increments of 0.4 or so. This was taken from nullschool Ocean Currents @ Surface for 2020-10-22 12:00 UTC; there is no forecast capacity. I don't know how accurate that data is nor if it improves on or agrees with other online SST product sources. All of them show the fringing around the ice pack periphery, the disconnect of the Chukchi-Bering inflow, and overall commonality (with mild pocketing) of the Laptev-ESS.

It's quite difficult to work with the low contrasts in the dark temperature palette nullschool provides; the image is best converted to '8-bit color' in ImageJ which allows palette replacement, done above with 'glasbey inverted' which by design makes consecutive colors as different as possible. Those bands could be color-picked and replaced with a conventional color gradient palette, worthwhile on a monthly time series.

It is perhaps better for people to just mouse around on that nullschool page, a click puts a green circle down and provides temperature data at that lat/lon. CMEMS, linked above, has better tools that allow temperature transects along lines and averages in polygonal box to be displayed. It may be more accurate; alternatively nullschool has just assimilated it (ie Mercator Ocean).

If we could locate the original infrared satellite image, there would still be the problem of  calibration algorithm. It's not clear how many independent determinations of SST exist. Forecasting products imply additional use of a model of which there are several. It's an interesting question how rapidly SST can change given the thermal inertia of sea water and how that is affected by wind and cold air temperature.

In the past, we've mostly just followed year-on-year SST atlantification at various depths at Mercator Ocean. It's worth delving in deeper to daily SST details this fall because of the extraordinary delay in Siberian refreeze.
Title: Re: The 2020/2021 freezing season
Post by: BornFromTheVoid on October 23, 2020, 12:36:04 PM
Here's an animation of the predicted sea ice and SSTs from the ECM

https://apps.ecmwf.int/webapps/opencharts/products/w_sst?area=Arctic&base_time=202010230000&level=sst&valid_time=202010230000
Title: Re: The 2020/2021 freezing season
Post by: A-Team on October 23, 2020, 01:03:51 PM
Can that be set for a narrower palette gamut (called squeeze at WorldView vs outlier clamp at CMEMS)? The bins are too large to resolve temperatures in the -2 to 0 and 0 to 2 ranges on the last frame of Nov 7th. The shoreline color seems off, not clear what temperature it is. Overall it does not seem that unreasonable: very little advance in the ice pack but with the stage still not set for rapid closure with so much open water between 0 to 2ºC.
Title: Re: The 2020/2021 freezing season
Post by: BornFromTheVoid on October 23, 2020, 01:34:39 PM
Can that be set for a narrower palette gamut (called squeeze at WorldView vs outlier clamp at CMEMS)? The bins are too large to resolve temperatures in the -2 to 0 and 0 to 2 ranges on the last frame of Nov 7th. The shoreline color seems off, not clear what temperature it is. Overall it does not seem that unreasonable: very little advance in the ice pack but with the stage still not set for rapid closure with so much open water between 0 to 2ºC.

It doesn't offer any other colour maps. It's easier to see in the full res in the link, but the discoloured shoreline is showing ice formation. Also, the dashed lines act as the 1ºC isotherms, providing slightly better resolution than the colour legend alone.
The website provides SSTAs at 0.5ºC intervals, which may help too. Not sure why they couldn't do that for the absolute SSTs...
Title: Re: The 2020/2021 freezing season
Post by: Shared Humanity on October 23, 2020, 01:55:10 PM
Have you seen the snow extent growth over Siberia and Western Canada? Anything to comment or you only rejoice on the bad feedbacks?

This is the freezing season thread so it is appropriate to focus on it.


Apart from this, the weather is about to become propitious for a quick rebound of sea ice next week.

I sure hope so.
Title: Re: The 2020/2021 freezing season
Post by: uniquorn on October 23, 2020, 02:35:23 PM
Mercator's take on SST's.
amsr2, awi dev v103 overlaid onto mercator 0m ocean temperature, sep4-oct22  (7MB)
Title: Re: The 2020/2021 freezing season
Post by: gandul on October 23, 2020, 03:14:30 PM
Mercator's take on SST's.
amsr2, awi dev v103 overlaid onto mercator 0m ocean temperature, sep4-oct22  (7MB)
Ok, from your animation is it correct to say all the regions susceptible to warming from Atlantic Waters are already covered by ice or about to be covered? (exception Barents and Kara but we know those two seas are already lost to climate change)
It seems to me the anomalously warm Laptev and ESS areas are basically over the shallow shelf, which will have a record heat release prior to refreeze (consistent with the record heat income from GAAC and the season in general). So no Atlantic warmth here to speak about.

In other words, 2021 and 2022 could be rebound years as probable as big melt years. I don’t see the doom scenario here (more in line with the scientific consensus of 2040+)
Title: Re: The 2020/2021 freezing season
Post by: aslan on October 23, 2020, 03:15:23 PM

Have you seen the snow extent growth over Siberia and Western Canada? Anything to comment or you only rejoice on the bad feedbacks?

https://www.ccin.ca/index.php/ccw/snow/current

Apart from this, the weather is about to become propitious for a quick rebound of sea ice next week.

Speaking of a great peril does not sound too much like being merry and joyfull... And for the snow extent, it is no news that late Autumn snow extent is not showing a significant decrease lately. It is even more the case this year. But this fact has not prevented ongoing anomalous warmth up to now. Which is still this case this year, as temperatures are still above normal overall in Siberia, no matter the snow extent. And for the quick rebound in ice extent we will see.

Can that be set for a narrower palette gamut (called squeeze at WorldView vs outlier clamp at CMEMS)? The bins are too large to resolve temperatures in the -2 to 0 and 0 to 2 ranges on the last frame of Nov 7th. The shoreline color seems off, not clear what temperature it is. Overall it does not seem that unreasonable: very little advance in the ice pack but with the stage still not set for rapid closure with so much open water between 0 to 2ºC.

There is also the SSTs from the coral watch of the NESDIS :

https://www.ospo.noaa.gov/data/sst/contour/global_small.fc.gif

Same picture, Laptev and even more Chukchi sea are not going to freeze tomorow...

Top level directory of the files are here :

ftp://ftp.star.nesdis.noaa.gov/pub/socd2/coastwatch/sst_blended/sst5km/

And the direct link for this year :

ftp://ftp.star.nesdis.noaa.gov/pub/socd2/coastwatch/sst_blended/sst5km/night/ghrsst_ospo/2020/
Title: Re: The 2020/2021 freezing season
Post by: aslan on October 23, 2020, 03:18:35 PM
Mercator's take on SST's.
amsr2, awi dev v103 overlaid onto mercator 0m ocean temperature, sep4-oct22  (7MB)
Ok, from your animation is it correct to say all the regions susceptible to warming from Atlantic Waters are already covered by ice or about to be covered? (exception Barents and Kara but we know those two seas are already lost to climate change)
It seems to me the anomalously warm Laptev and ESS areas are basically over the shallow shelf, which will have a record heat release (consistent with the record heat income from GAAC and the season in general). So no Atlantic warmth here to speak about.

The Laptev sea extent beyond the shelf (and so the heat anomaly, by the way). Intrusion of Atlantic waters are discernible on the salinity maps of the mercator. (P.S. : And acknoledging that the heat and salinity extent beyond the Laptev into the central bassin, even under the sea ice).
Title: Re: The 2020/2021 freezing season
Post by: Sublime_Rime on October 23, 2020, 03:20:30 PM
My apologies if this is an ignorant or rookie question, but has anyone looked at the integral of sea ice extent, area and volume across a given year, or year-to-date, in order to quantitatively compare them with regard to sea ice coverage?

I think that would highlight 2020's prominance more clearly over past years, even 2012, with regard to the amount of time its been in the lead and by how much. This comparison would give equal measure to all time points (as I think they 'deserve') rather than having bias as to the minimum and maximum. Such an analysis may help to see an overall trend over the years, relative to looking at particular time-points.

I think volume may be the most sensitive metric to use, as sea ice area and extent seem to have much less variation during the winter, and those large numbers may blunt changes occurring from year-to-year.
Title: Re: The 2020/2021 freezing season
Post by: uniquorn on October 23, 2020, 03:40:46 PM
Mercator's take on SST's.
amsr2, awi dev v103 overlaid onto mercator 0m ocean temperature, sep4-oct22  (7MB)
Ok, from your animation is it correct to say all the regions susceptible to warming from Atlantic Waters are already covered by ice or about to be covered? (exception Barents and Kara but we know those two seas are already lost to climate change)
It seems to me the anomalously warm Laptev and ESS areas are basically over the shallow shelf, which will have a record heat release (consistent with the record heat income from GAAC and the season in general). So no Atlantic warmth here to speak about.

The Laptev sea extent beyond the shelf (and so the heat anomaly, by the way). Intrusion of Atlantic waters are discernible on the salinity maps of the mercator. (P.S. : And acknoledging that the heat and salinity extent beyond the Laptev into the central bassin, even under the sea ice).
Yes, SST is more useful if we also show SSS
amsr2, awi dev v103 overlaid at 75% transparent onto mercator 0m ocean salinity, sep4-oct22  (7MB)
mercator label is just visible.
edit: It has often been proposed that the Atlantic waters would meet the Pacific incoming at some point. The delay in refreeze and perhaps some mixing from recent strong winds would seem to make that prospect more likely (according to the model). The Siberian shelf and the Chukchi plateau help to prevent it. (Shown on the 92m salinity map upthread)
Title: Re: The 2020/2021 freezing season
Post by: kassy on October 23, 2020, 04:53:09 PM
Have you seen the snow extent growth over Siberia and Western Canada? Anything to comment or you only rejoice on the bad feedbacks?
...
apart from this, the weather is about to become propitious for a quick rebound of sea ice next week.

This seems like an emotional type response, especially as a reply to such an informative post which did not actually feature any rejoicing...

The previous posts were an actual attempt at figuring out some of the extent of the damage done.

A quick rebound next week would already be late but both recent comments in this thread and in the SIA&E thread hint that the it might not be quick.

You are thinking too much about the area/extent (so 2D) while ignoring the 3D problems like the stall in TPD.

Quote
In other words, 2021 and 2022 could be rebound years as probable as big melt years. I don’t see the doom scenario here (more in line with the scientific consensus of 2040+)

In case you missed it we are discussing what we see. Oh and i think that scientific consensus might have shifted a bit...
Title: Re: The 2020/2021 freezing season
Post by: Shared Humanity on October 23, 2020, 05:04:29 PM
I prefer looking at 2m temperatures instead of anomalies when trying to determine when freezing might occur. Much of the Laptev and ESS are no more than -4C. With large areas of water at 1C, we're going to need to wait to see dramatic freeze.
Title: Re: The 2020/2021 freezing season
Post by: Shared Humanity on October 23, 2020, 05:12:24 PM
The entire Arctic Ocean is cloud covered. Is this slowing down the release of heat?
Title: Re: The 2020/2021 freezing season
Post by: SimonF92 on October 23, 2020, 05:24:11 PM
My apologies if this is an ignorant or rookie question, but has anyone looked at the integral of sea ice extent, area and volume across a given year, or year-to-date, in order to quantitatively compare them with regard to sea ice coverage?

I think that would highlight 2020's prominance more clearly over past years, even 2012, with regard to the amount of time its been in the lead and by how much. This comparison would give equal measure to all time points (as I think they 'deserve') rather than having bias as to the minimum and maximum. Such an analysis may help to see an overall trend over the years, relative to looking at particular time-points.

I think volume may be the most sensitive metric to use, as sea ice area and extent seem to have much less variation during the winter, and those large numbers may blunt changes occurring from year-to-year.

I think this is a really good idea, would you be willing to have a go at it? Otherwise I can try to pick it up
Title: Re: The 2020/2021 freezing season
Post by: Freegrass on October 23, 2020, 05:35:08 PM
Latest Five Day Forecast
Wind + Temp @ Surface
Large GiF!

More heat and moisture coming in with a new storm from Europe this time...
Title: Re: The 2020/2021 freezing season
Post by: A-Team on October 23, 2020, 05:43:08 PM
Quote
weather is about to become propitious for a quick rebound of sea ice next week.
The time series below looks at the rate of change of SST over the last 16 weeks at 5 day intervals at a single central Laptev site, lat 77.77º. The open water surface temperature peaked at an astonishing 7.3ºC on Aug 17th.

There do not seem to have been any profiler buoys in the area so no data on how this temperature changed with depth to shelf. For shallow water and stratification lost to atlantification, the water may be fairly well mixed and the temperature profile flat.

It would have been better to take a 'reading' every day rather than every fifth, then repeating at say a dozen different locations by loading a list of manufactured urls as browser tabs, then turning the data over to Geronto for graphing with some kind of multi-regressional best fit. 

Another way to go is with a quantitative CMEMS grayscale for a 2D time series of the whole Siberian side. These can literally be subtracted to get at numerical temperature change between any two dates, put into a heat map palette, and averaged over any polygonal region. However CMEMS is very taken with politically correct (perceptually uniform) palettes; the grayscale may or may not be affected.

The series shown went from to 6.9ºC to 1.0ºC in 65 days, cooling roughly 0.1º per day. This could be quite misleading from a thermodynamic standpoint if vertical turbulence or horizontal currents shifted water masses about. Really severe and persistent cold air could also set in, contrary to forecast and past climatology.

However, if the nominal trend continues, the water at this lat/lon would reach -1.8º in the last week of November.
Title: Re: The 2020/2021 freezing season
Post by: FishOutofWater on October 23, 2020, 05:52:57 PM
Warm water in the Barents and Kara seas is known to enhance Urals ridging, inducing a downstream trough in central Siberia. Judah Cohen discussed this issue in his latest blog post. This pattern causes snowfall extent to grow rapidly in October in Siberia and may cause a warm Arctic cold Siberia pattern to develop as fall progresses into winter. Moreover, a warm Arctic cold continents pattern may develop where a cold pool develops in central Canada mirroring the cold in central Siberia. That appears to be what's beginning now.

However, as winter progresses, this pattern enhances upward wave activity into the stratosphere. The weak polar vortex that develops in mid-winter may suddenly break down in the stratosphere causing a major stratospheric warming. Sudden stratospheric warmings may lead to subsidence and high pressure over the pole in February or March, which could be favorable to ice thickening. However, it could also lead to a rapid transition to spring warmth in the Arctic. These are tings we have seen in the past decade that could be exaggerated this winter by the warmth that will persist on the Atlantic side of the Arctic because of the high heat content of the Barents sea waters.

It's going to be an interesting winter.
Title: Re: The 2020/2021 freezing season
Post by: Freegrass on October 23, 2020, 05:53:33 PM
Quote
temperature labels would be useful on the above graphic
The purple is -1.8ºC under the ice pack and it goes up from there in increments of 0.4 or so. This was taken from nullschool Ocean Currents @ Surface for 2020-10-22 12:00 UTC; there is no forecast capacity. I don't know how accurate that data is nor if it improves on or agrees with other online SST product sources. All of them show the fringing around the ice pack periphery, the disconnect of the Chukchi-Bering inflow, and overall commonality (with mild pocketing) of the Laptev-ESS.

It's quite difficult to work with the low contrasts in the dark temperature palette nullschool provides; the image is best converted to '8-bit color' in ImageJ which allows palette replacement, done above with 'glasbey inverted' which by design makes consecutive colors as different as possible. Those bands could be color-picked and replaced with a conventional color gradient palette, worthwhile on a monthly time series.

It is perhaps better for people to just mouse around on that nullschool page, a click puts a green circle down and provides temperature data at that lat/lon. CMEMS, linked above, has better tools that allow temperature transects along lines and averages in polygonal box to be displayed. It may be more accurate; alternatively nullschool has just assimilated it (ie Mercator Ocean).

If we could locate the original infrared satellite image, there would still be the problem of  calibration algorithm. It's not clear how many independent determinations of SST exist. Forecasting products imply additional use of a model of which there are several. It's an interesting question how rapidly SST can change given the thermal inertia of sea water and how that is affected by wind and cold air temperature.

In the past, we've mostly just followed year-on-year SST atlantification at various depths at Mercator Ocean. It's worth delving in deeper to daily SST details this fall because of the extraordinary delay in Siberian refreeze.
I think Nullschool is using publicly available data to render these maps, so wouldn't it be easier to cut out Nullschool completely and make something yourself directly from the available data?
Title: Re: The 2020/2021 freezing season
Post by: Shared Humanity on October 23, 2020, 05:54:03 PM
If the nominal trend continues, the water at this lat/lon would reach -1.8º in the last week of November.

Shit. :-[
Title: Re: The 2020/2021 freezing season
Post by: SimonF92 on October 23, 2020, 06:33:43 PM
Quote
temperature labels would be useful on the above graphic
The purple is -1.8ºC under the ice pack and it goes up from there in increments of 0.4 or so. This was taken from nullschool Ocean Currents @ Surface for 2020-10-22 12:00 UTC; there is no forecast capacity. I don't know how accurate that data is nor if it improves on or agrees with other online SST product sources. All of them show the fringing around the ice pack periphery, the disconnect of the Chukchi-Bering inflow, and overall commonality (with mild pocketing) of the Laptev-ESS.

It's quite difficult to work with the low contrasts in the dark temperature palette nullschool provides; the image is best converted to '8-bit color' in ImageJ which allows palette replacement, done above with 'glasbey inverted' which by design makes consecutive colors as different as possible. Those bands could be color-picked and replaced with a conventional color gradient palette, worthwhile on a monthly time series.

It is perhaps better for people to just mouse around on that nullschool page, a click puts a green circle down and provides temperature data at that lat/lon. CMEMS, linked above, has better tools that allow temperature transects along lines and averages in polygonal box to be displayed. It may be more accurate; alternatively nullschool has just assimilated it (ie Mercator Ocean).

If we could locate the original infrared satellite image, there would still be the problem of  calibration algorithm. It's not clear how many independent determinations of SST exist. Forecasting products imply additional use of a model of which there are several. It's an interesting question how rapidly SST can change given the thermal inertia of sea water and how that is affected by wind and cold air temperature.

In the past, we've mostly just followed year-on-year SST atlantification at various depths at Mercator Ocean. It's worth delving in deeper to daily SST details this fall because of the extraordinary delay in Siberian refreeze.
I think Nullschool is using publicly available data to render these maps, so wouldn't it be easier to cut out Nullschool completely and make something yourself directly from the available data?

The data is here

https://resources.marine.copernicus.eu/?option=com_csw&view=details&product_id=GLOBAL_ANALYSIS_FORECAST_PHY_001_024

and is in NetCDF format.

Maybe better to continue this is the Dev corner
Title: Re: The 2020/2021 freezing season
Post by: oren on October 23, 2020, 06:43:19 PM
Yes, SST is more useful if we also show SSS
amsr2, awi dev v103 overlaid at 75% transparent onto mercator 0m ocean salinity, sep4-oct22 
Thanks for this uniquorn.
Looking at the animation, it would appear SSS is even more predictive of where refreeze might hit.

In general, I want to commend the very high level of discussion and the collection of excellent posts by several contributors. I can barely keep up... but this exceptional "freezing" season deserves all the analysis it can get.
Title: Re: The 2020/2021 freezing season
Post by: oren on October 23, 2020, 06:47:04 PM
My apologies if this is an ignorant or rookie question, but has anyone looked at the integral of sea ice extent, area and volume across a given year, or year-to-date, in order to quantitatively compare them with regard to sea ice coverage?

I think that would highlight 2020's prominance more clearly over past years, even 2012, with regard to the amount of time its been in the lead and by how much. This comparison would give equal measure to all time points (as I think they 'deserve') rather than having bias as to the minimum and maximum. Such an analysis may help to see an overall trend over the years, relative to looking at particular time-points.

I think volume may be the most sensitive metric to use, as sea ice area and extent seem to have much less variation during the winter, and those large numbers may blunt changes occurring from year-to-year.

I think this is a really good idea, would you be willing to have a go at it? Otherwise I can try to pick it up
If I understand correctly, this would partly be covered by Gero's 365-day extent average, posted regularly in its own thread. As for volume I seem to recall he also made such a chart, and there's also my own modest chart detailing the number of daily records held by each year. For all measures, 2020 is still behind a combination of 2016-17, however this could change quite quickly as the "Siberian Seas problem" continues to develop and considering the low minima achieved this year.
Title: Re: The 2020/2021 freezing season
Post by: gandul on October 23, 2020, 06:49:30 PM
If the nominal trend continues, the water at this lat/lon would reach -1.8º in the last week of November.

Shit. :-[

Good, we’ll see.
I am more worried about the Chukchi sea refreeze, I believe the Bering strait may have another “blue” Christmas in what is becoming more frequent later refreeze.
Title: Re: The 2020/2021 freezing season
Post by: gandul on October 23, 2020, 06:57:23 PM
Have you seen the snow extent growth over Siberia and Western Canada? Anything to comment or you only rejoice on the bad feedbacks?
...
apart from this, the weather is about to become propitious for a quick rebound of sea ice next week.

This seems like an emotional type response, especially as a reply to such an informative post which did not actually feature any rejoicing...

The previous posts were an actual attempt at figuring out some of the extent of the damage done.

A quick rebound next week would already be late but both recent comments in this thread and in the SIA&E thread hint that the it might not be quick.

You are thinking too much about the area/extent (so 2D) while ignoring the 3D problems like the stall in TPD.

Quote
In other words, 2021 and 2022 could be rebound years as probable as big melt years. I don’t see the doom scenario here (more in line with the scientific consensus of 2040+)

In case you missed it we are discussing what we see. Oh and i think that scientific consensus might have shifted a bit...
Yes Kassy it’s an emotional response because I get the feeling people choose to not talk about that, there may be other mechanisms that kick in and explain why the Arctic didn’t completely tank 8 years ago.

Rebound years (08/09, 13/14, 17/18) are surrounded by certain mystery or silence.

Ok I’ll try to open that discussion in another thread.
In any case the posts here lately are excellent, I don’t deny people are well informed, much better than me in any case.
Title: Re: The 2020/2021 freezing season
Post by: SimonF92 on October 23, 2020, 07:33:08 PM
My apologies if this is an ignorant or rookie question, but has anyone looked at the integral of sea ice extent, area and volume across a given year, or year-to-date, in order to quantitatively compare them with regard to sea ice coverage?

I think that would highlight 2020's prominance more clearly over past years, even 2012, with regard to the amount of time its been in the lead and by how much. This comparison would give equal measure to all time points (as I think they 'deserve') rather than having bias as to the minimum and maximum. Such an analysis may help to see an overall trend over the years, relative to looking at particular time-points.

I think volume may be the most sensitive metric to use, as sea ice area and extent seem to have much less variation during the winter, and those large numbers may blunt changes occurring from year-to-year.

I think this is a really good idea, would you be willing to have a go at it? Otherwise I can try to pick it up
If I understand correctly, this would partly be covered by Gero's 365-day extent average, posted regularly in its own thread. As for volume I seem to recall he also made such a chart, and there's also my own modest chart detailing the number of daily records held by each year. For all measures, 2020 is still behind a combination of 2016-17, however this could change quite quickly as the "Siberian Seas problem" continues to develop and considering the low minima achieved this year.

It did it myself just for a bit of practice parsing .dat files
Title: Re: The 2020/2021 freezing season
Post by: SimonF92 on October 23, 2020, 07:34:11 PM
Actually this is clearer

(And i added up to day313 so that we could see 2020)
Title: Re: The 2020/2021 freezing season
Post by: I’M IN LOVE WITH A RAGER on October 23, 2020, 07:47:28 PM
Pardon my potential lack of comprehension, but what does the 0 baseline on the Y-axis of the graph mean, Simon? How significant is the sub-0 data point in 2016? Regardless, this seems to be a very interesting representation of the data and I am excited to see how this line of thought continues to develop.
Title: Re: The 2020/2021 freezing season
Post by: SimonF92 on October 23, 2020, 07:57:45 PM
Pardon my potential lack of comprehension, but what does the 0 baseline on the Y-axis of the graph mean, Simon? How significant is the sub-0 data point in 2016? Regardless, this seems to be a very interesting representation of the data and I am excited to see how this line of thought continues to develop.

I actually dont know Rager, i think it might be something to do with a weighted value to the polyfit? I checked it using Simpsons integration and there were even more -'s. Any statisticians around here at the moment care to wade in?
Title: Re: The 2020/2021 freezing season
Post by: FishOutofWater on October 23, 2020, 08:24:51 PM
Those Arctic sea ice recovery years had major sudden stratospheric warming events in midwinter.

A dry clear dome of high pressure over the pole in February or early March is ideal for radiating heat to space and thickening the ice around the pole.

https://www.researchgate.net/publication/329104906_The_Stratospheric_Sudden_Warming_Event_in_February_2018_and_its_Prediction_by_a_Climate_System_Model

and

https://www.mdpi.com/2073-4433/10/9/519/pdf
Title: Re: The 2020/2021 freezing season
Post by: Freegrass on October 23, 2020, 10:35:32 PM
The Laptev is still warm at 30m depth. Is that heavier salty water? Too bad we can't see the temperature at 10 or 20 meters depth on the Siberian shelf....

Edit:
Just saw that you can create links to a zoomed in area directly on the website.
http://bulletin.mercator-ocean.fr/en/permalink/PSY4/20201023/map/3/1/2#5/68.302/-54.075
Title: Re: The 2020/2021 freezing season
Post by: morganism on October 23, 2020, 11:26:12 PM
That sure looks like the Greenland Crack is opening again....?

https://forum.arctic-sea-ice.net/index.php?action=dlattach;topic=3299.0;attach=289522;image
Title: Re: The 2020/2021 freezing season
Post by: A-Team on October 24, 2020, 12:14:31 AM
Quote
Too bad we can't see the temperature at 10 meters depth on the Siberian shelf
Measurement of SST is quite complex, involving numerous satellites:

"For the Global Ocean- Sea Surface Temperature L3 Observations . This product provides daily foundation sea surface temperature from multiple satellite sources. The data are intercalibrated. This product consists in a fusion of sea surface temperature observations from multiple satellite sensors, daily, over a 0.1° resolution global grid. It includes observations by polar orbiting (NOAA-18 & NOAAA-19/AVHRR, METOP-A/AVHRR, ENVISAT/AATSR, AQUA/AMSRE, TRMM/TMI) and geostationary (MSG/SEVIRI, GOES-11) satellites . The observations of each sensor are inter-calibrated prior to merging using a bias correction based on a multi-sensor median reference correcting the large-scale cross-sensor biases"

There's a reason for not showing the 10m (see image below):

"SST is a challenging parameter to define precisely as the upper ocean (~10 m) has a complex and variable vertical temperature structure that is related to ocean turbulence and air-sea fluxes of heat, moisture and momentum.

The interface temperature (SSTint): At the exact air-sea interface a hypothetical temperature called the interface temperature (SSTint) is defined although this is of no practical use because it cannot be measured using current technology.

The skin sea surface temperature (SSTskin): The skin temperature is defined as the temperature measured by an infrared radiometer typically operating at wavelengths 3.7-12 µm (chosen for consistency with the majority of infrared satellite measurements) that represents the temperature within the conductive diffusion-dominated sub-layer at a depth of ~10-20 µm. SSTskin measurements are subject to a large potential diurnal cycle including cool skin layer effects (especially at night under clear skies and low wind speed conditions) and warm layer effects in the daytime.

The sub-skin sea surface temperature (SSTsub-skin): The subskin temperature represents the temperature at the base of the conductive laminar sub-layer of the ocean surface. For practical purposes, SSTsubskin can be well approximated to the measurement of surface temperature by a microwave radiometer operating in the 6-11 GHz frequency range, but the relationship is neither direct nor invariant to changing physical conditions or to the specific geometry of the microwave measurements.

[[See https://tinyurl.com/yyab3s5e for subskin temperatures loaded at CMEMS-Lobelia]]

The surface temperature at depth (SSTz or SSTdepth): All measurements of water temperature beneath the SSTsubskin are referred to as depth temperatures (SSTdepth) measured using a wide variety of platforms and sensors such as drifting buoys, vertical profiling floats, or deep thermistor chains at depths ranging from 0.01 – 1000m. These temperature observations are distinct from those obtained using remote sensing techniques (SSTskin and SSTsubskin) and must be qualified by a measurement depth in meters (e.g., or SST(z) e.g. SST5m).

The foundation temperature (SSTfnd): The foundation SST  is the temperature free of diurnal temperature variability, defined as the temperature at the first time of the day when the heat gain from the solar radiation absorption exceeds the heat loss at the sea surface. For conditions, when the SST increases or decreases monotonically over several days, the Tfnd occurs on a given day when the time rate of change of temperature is at a minimum (increasing SST), or a maximum (decreasing SST). If such a point in the daily time series cannot be identified, the SSTfnd should be set to a clearly stated time. SSTfnd is named to indicate that it is the foundation temperature upon which the growth and decay of the diurnal heating develops each day. Only in situ contact thermometry is able to measure SSTfnd and analysis procedures must be used to estimate the SSTfnd from radiometric retrievals of SSTskin and SSTsubskin taken at other times of the day."

https://www.ghrsst.org/ghrsst-data-services/products/

Quote
you can create links to a zoomed in area
The problem with that, as noted many times earlier, is that Mercator Ocean does not use quite the same scale for 0 and 30m, meaning that the colors cannot be compared directly. Instead, the fixed palette png's have to be used but these lose the zoom.

The animation below provides a flash comparator of the 0 and 30m temperatures with the same color definitions of temperature. The 30m is considerably warmer in the Bering Strait and Chukchi region. That holds for the Laptev as well possibly reflecting AW intrusion. The continental shelf to 30m has been grayed out on the 0m to minimize confusion.
Title: Re: The 2020/2021 freezing season
Post by: FishOutofWater on October 24, 2020, 12:53:23 AM
There's an apparent current of warm salty Atlantic water along the shelf edge, Freegrass. You can see the shelf margin and warm salty water at the 100m depth.

http://bulletin.mercator-ocean.fr/en/PSY4#5/68.302/-54.097
http://bulletin.mercator-ocean.fr/en/PSY4#5/68.302/-54.097
The next 2 figures show the current at 100m, according to the Mercator model& the sea surface height which is a critical input to the model.
http://bulletin.mercator-ocean.fr/en/PSY4#5/68.302/-54.097
http://bulletin.mercator-ocean.fr/en/PSY4#5/68.302/-54.097
Title: Re: The 2020/2021 freezing season
Post by: Aluminium on October 24, 2020, 05:38:58 AM
October 19-23.

2019 (https://forum.arctic-sea-ice.net/index.php/topic,2888.msg234059.html#msg234059).
Title: Re: The 2020/2021 freezing season
Post by: Sublime_Rime on October 24, 2020, 06:04:30 AM

It did it myself just for a bit of practice parsing .dat files

Thanks Simon! Nice work with those last two. I tried doing the same by just taking the average of the monthly data for each year as a bar graph, but it didn't come out as nicely so far. Suggests as Oren said that 2020 hasn't overcome the long stretches of low volumes in 2016-2017, but may still in the weeks to come.
Title: Re: The 2020/2021 freezing season
Post by: BornFromTheVoid on October 24, 2020, 12:06:52 PM
Here's the slow animation for the past week. Still areas of loss occurring, which surprised me a little.
Title: Re: The 2020/2021 freezing season
Post by: Freegrass on October 24, 2020, 12:53:46 PM
Here's the slow animation for the past week. Still areas of loss occurring, which surprised me a little.
It doesn't really surprise me. When you look at the HYCOM ice animation I posted a few days go, you can see that the ice there is expanding instead of freezing from the edge. So my guess is that there's a lot of dispersion going on, with leads at the center freezing up, while the ice edge moves over warmer water. And that can still melt the ice edge of course...

https://forum.arctic-sea-ice.net/index.php/topic,3299.msg290729.html#msg290729 (https://forum.arctic-sea-ice.net/index.php/topic,3299.msg290729.html#msg290729)

Thank you for the explanation A-Team and FOoW! Love the animation with the temperature difference at different depths. Hope to see more of those throughout the year. That may tell us how fast the water is warming up or cooling down in the shallows.

Will that warmer water at 30m prevent ice from forming? Or will it be added to the energy balance in the deep ocean as it's been dragged down with the brine that's released out of the big icemaker?
Title: Re: The 2020/2021 freezing season
Post by: gandul on October 24, 2020, 01:53:07 PM
Here's the slow animation for the past week. Still areas of loss occurring, which surprised me a little.
Could it be a late Bering pulse affecting the ice edge?
Chukchi sea looks really warm and I wonder if there has been significant Bering inflow in Sep/Oct while we were not particularly looking in that direction.
Title: Re: The 2020/2021 freezing season
Post by: gandul on October 24, 2020, 02:02:03 PM
Mercator's take on SST's.
amsr2, awi dev v103 overlaid onto mercator 0m ocean temperature, sep4-oct22  (7MB)
Ok, from your animation is it correct to say all the regions susceptible to warming from Atlantic Waters are already covered by ice or about to be covered? (exception Barents and Kara but we know those two seas are already lost to climate change)
It seems to me the anomalously warm Laptev and ESS areas are basically over the shallow shelf, which will have a record heat release (consistent with the record heat income from GAAC and the season in general). So no Atlantic warmth here to speak about.

The Laptev sea extent beyond the shelf (and so the heat anomaly, by the way). Intrusion of Atlantic waters are discernible on the salinity maps of the mercator. (P.S. : And acknoledging that the heat and salinity extent beyond the Laptev into the central bassin, even under the sea ice).
Yes, SST is more useful if we also show SSS
amsr2, awi dev v103 overlaid at 75% transparent onto mercator 0m ocean salinity, sep4-oct22  (7MB)
mercator label is just visible.
edit: It has often been proposed that the Atlantic waters would meet the Pacific incoming at some point. The delay in refreeze and perhaps some mixing from recent strong winds would seem to make that prospect more likely (according to the model). The Siberian shelf and the Chukchi plateau help to prevent it. (Shown on the 92m salinity map upthread)

This animation by Uniquorn shows, I believe,Bering inflow late in the season and beyond, and the pool of warm water being dragged, at least superficially, well into the Pacific side of the Arctic (by winds?)
Title: Re: The 2020/2021 freezing season
Post by: Freegrass on October 24, 2020, 02:15:12 PM
Latest Five Day Forecast
Wind @ Surface + Total Precipitable Water
Wind + Temp @ 850hPa
Large GiFS!

Another heat bomb is about to enter the Arctic again...
Title: Re: The 2020/2021 freezing season
Post by: uniquorn on October 24, 2020, 03:10:02 PM
A closer look at refreeze not keeping up with dispersion in the Beaufort yesterday, amsr2 awi v103 oct12-23. Winds were not strong, just a little warmer.

Also moving the conversation about whoi itp121 (https://forum.arctic-sea-ice.net/index.php/topic,3017.msg288031.html#msg288031) from the melting season to this thread. Latest temperature/salinity profiles and drift path.
Temperature at 50m still high at over 2C.

itp121 shares a floe with ice mass balance buoy www.cryosphereinnovation.com/441910 currently maintaining thickness at ~2m.
Title: Re: The 2020/2021 freezing season
Post by: Général de GuerreLasse on October 24, 2020, 03:11:29 PM
Latest Five Day Forecast
Wind @ Surface + Total Precipitable Water
Wind + Temp @ 850hPa
Large GiFS!

Another heat bomb is about to enter the Arctic again...

Hi Freegrass, I hope your heat bomb won't do too much damage. I was thinking that Mercator's forecast for 11/02 was already not very good...
Title: Re: The 2020/2021 freezing season
Post by: FishOutofWater on October 24, 2020, 03:24:14 PM
The warm salty Atlantic water inflow to the Laptev sea will increase the "Atlantification" of the Siberian seas as winter progresses. Of course, it's going to get cold in the coming winter months and ice will form but the ice will be thinner than it used to be and more heat will escape to the atmosphere. This heat transfer will increase the formation of relatively dense water which will sink along the continental shelf margin.

Over the past 2 years we have watched an influx of Atlantic water into the Siberian seas, the formation of a subsurface summer water layer by flow off the Chukchi shelf, and the movement of a very large volume of relatively fresh sea water towards the Canadian side of the Arctic ocean. We have measures of the amount of ice flowing out of the Fram strait, but we have not been accounting for the large volume of melted ice that is flowing out below the surface down to the 300m level.

Also note that Mercator animations show that fresh Siberian shelf water separates the Atlantic waters from the Pacific waters as they all flow off the Chukchi and Siberian shelves. Those waters sink to different depths depending on their density. Mixing occurs in eddies.

Freegrass, that's an excellent cartoon of flow off the shelf edge, but there's one thing that needs updating. All the ice will be first year ice this year. There is no multi-year ice anywhere close to Siberia.
Title: Re: The 2020/2021 freezing season
Post by: FishOutofWater on October 24, 2020, 03:39:42 PM
Thanks, Uniquorn for that visualization of the Beaufort sea. The rapid ice area increase was caused by advection from the CAA side of the Arctic ocean. Although we have seen evidence of freezing and ice formation, that animation shows evidence of ongoing bottom melt. That's quite unsettling given that it's late October. The thickest multi year ice in the CAA is moving towards the Beaufort sea, setting it up for melting out next summer.
Title: Re: The 2020/2021 freezing season
Post by: Niall Dollard on October 24, 2020, 04:16:27 PM
Sample forecast chart (for yesterday) from NOAA's Physical Science Lab backing up what has been said already. Bottom melt (greens/blues) is still ongoing on the edges of the pack. In particular near Severnaya Zemlya and also in the far SE of Beaufort. Of the order of about 1cm per day.

Meanwhile bottom growth (beige/reds) is indicated away from the edges (about 1cm per day).
Title: Re: The 2020/2021 freezing season
Post by: A-Team on October 24, 2020, 06:22:37 PM
As being noted above, it's difficult to distinguish lateral ice extension from just the wind pushing things around. The first graphic below just overlays OsiSaf's observed floe motions over BVoid's gain'/oss for the week. The outflows/inflows line up quite closely with green/red for gain/loss suggesting growth towards the Siberian side has stalled.

The 2nd image just shows the vertical salinity gradient. As FooW notes, that cartoon above of the Barents front is not applicable to the Laptev; atlantification has joined up with pacification of the Chukchi which FooW/Uniq anticipated last year.

Aslan #482 posted very helpful direct links to sea surface temperatures data. Usually these go to a massive opaque portal featuring guys in suits cheering a satellite rocket launch; you then spend an hour drilling around for actual data only to find no thumbnails and the netCDFs formatted all wrong. Here everything was done perfectly (3rd image): from seamless ftp to Geo2D, land/ice masks, error analysis etc.

ftp://ftp.star.nesdis.noaa.gov/pub/socd2/coastwatch/sst_blended/sst5km/night/ghrsst_ospo/2020/

The inset, lower right, shows a bit of the raw numerical temperature array in kelvin for the point in the Laptev at 77.77ºN whose time-dependent temperature series was calculated in #491 above from Nullschool (which uses this same data source for its popups).

CMEMS-Lobelia and Mercator Ocean also use this same data -- it's all provided by an SST expert group from 11 institutions called GHRSST. No way we can approach this quality looking at WorldView infrared bands on our own!

https://www.ghrsst.org/latest-sst-map/

The arithmetic operations shown as available within Panoply allow differencing of SST between any two dates across the entire Arctic Ocean. From there, it is straightforward to make a red gain in temperature png and a blue loss that are easily combined in Gimp (4th illustration). It's also easy to copy out a column of the raw data display and plot a constant-longitude transect from the Siberian shore to the ice edge.

Regardless how this or that online service might display SST, we can always go back to this raw data to see what the real spatial resolution was and the uncertainty associated with the SST determination. Here the polar latitude and longitude both bump by 0.05º per bin making pixels 5.7km on a side with temperature provided to 0.1K precision.
Title: Re: The 2020/2021 freezing season
Post by: Freegrass on October 24, 2020, 06:49:02 PM
Who is going to ask Google Earth to add all this data to their globe? How awesome would it be if we could use Google Earth Ocean to go below the surface to see the salinity and temperature of the water in 3D...
Title: Re: The 2020/2021 freezing season
Post by: RoxTheGeologist on October 24, 2020, 09:30:29 PM
...
Freegrass, that's an excellent cartoon of flow off the shelf edge, but there's one thing that needs updating. All the ice will be first year ice this year. There is no multi-year ice anywhere close to Siberia.


.... and the halocline is much closer to the surface.
Title: Re: The 2020/2021 freezing season
Post by: Freegrass on October 24, 2020, 10:24:14 PM
...
Freegrass, that's an excellent cartoon of flow off the shelf edge, but there's one thing that needs updating. All the ice will be first year ice this year. There is no multi-year ice anywhere close to Siberia.


.... and the halocline is much closer to the surface.
I understand things are a lot more complicated than what the cartoon depicted. But when I look at that cartoon, I start thinking about the feeding mechanism for the halocline. When less ice is formed, there will also be less salt released. I'm curious how this will affect the halocline. I'm pretty sure its bad, and another invisible positive feedback loop?

One more thing I'd like to know is if that 200m should be 80m now?
Title: Re: The 2020/2021 freezing season
Post by: morganism on October 24, 2020, 10:55:16 PM
Will this toxic spill In Siberia act like antifreeze?

"The Russian branch of Greenpeace pointed to a nearby toxic waste dump as a possible source of the leak. Kamchatka officials revealed Tuesday that the perimeter at Kozelsky site, which stores over 100 tons of toxic substances, including pesticides, had been breached. (high phenol levels measured too).

There was also a large oil spill near Novilisk few months ago.

Cnn n Siberian Times carrying stories
Title: Re: The 2020/2021 freezing season
Post by: A-Team on October 25, 2020, 12:52:51 AM
Here is the Oct 23rd situation. Panoply makes a quite decent no-click map out of GHRSST data with a little help from AMSR2_AWI, OsiSaf and Gimp. Click to see at full resolution of the data source. Note this is SSTfnd, not skin or subskin temperatures. The contour lines correspond to tick mark bins in the palette.

What this is saying is the open water is far too warm from the surface down to 10m depth to even be talking about ice forming without really cold air. Right now, the 2m air temperature at 85º on the 140th meridian connecting the NSI to the North Pole is -2ºC. Please remind me to make a new map when it is has been -35ºC for a couple weeks!

Late fall temperatures seen by the Polarstern:
https://www.awi.de/fileadmin/user_upload/MET/PolarsternCoursePlot/psobsedat.html

(https://forum.arctic-sea-ice.net/index.php?action=dlattach;topic=3299.0;attach=289598;image)
20201023000000-OSPO-L4_GHRSST-SSTfnd-Geo_Polar_Blended_Night-GLOB-v02.0-fv01.0.nc
Title: Re: The 2020/2021 freezing season
Post by: Glen Koehler on October 25, 2020, 02:46:11 AM
      The Panoply map is very interesting.  What are typical cooling rates for November, December, and January?  In other words, what does a current temperature of 273-275K in most of the ESS and Laptev, and much of the Kara, suggest for when those waters are likely to freeze?
      Here is CR temperature anomaly map for same day.  It is an apples vs oranges comparison because Panoply and CR  are not representing temperature at the same depth in addition to using different data sources.     
Title: Re: The 2020/2021 freezing season
Post by: jdallen on October 25, 2020, 08:25:25 AM
      The Panoply map is very interesting.  What are typical cooling rates for November, December, and January?  In other words, what does a current temperature of 273-275K in most of the ESS and Laptev, and much of the Kara, suggest for when those waters are likely to freeze?
 
It's not what they suggest now.

It's what they augur for spring that is significant.

There is no ice.  There will likely be no ice over large stretches of that open water for weeks.

Right now, it looks like we'll be flying under 2016's numbers by close to half a million km2 for most of the refreeze season.  Come March, that will potentially be half a million km2 of exposed ocean sucking up heat and not reflecting it back out of the atmosphere as the sun returns.

Even when enough heat has been dumped for that water to freeze, with the coverage we'll get, those higher temperatures will mean thinner ice, by 10's of centimeters, which will be more vulnerable and melt out faster when the sun starts to return.

I'm expecting an early max, and a return of May melt ponds next spring, is the take-away I have of these numbers.

Title: Re: The 2020/2021 freezing season
Post by: interstitial on October 25, 2020, 09:31:43 AM
The later it refreezes the steeper the ramp rate will be. Still at those lattitudes in late October there is probably so little sun the ramp rate of sea ice is pretty close to maximum.
Title: Re: The 2020/2021 freezing season
Post by: oren on October 25, 2020, 09:37:13 AM
Quote
Right now, it looks like we'll be flying under 2016's numbers by close to half a million km2 for most of the refreeze season.  Come March, that will potentially be half a million km2 of exposed ocean sucking up heat and not reflecting it back out of the atmosphere as the sun returns.
The Siberian seas are currently very much delayed. However extent max is set elsewhere, in Baffin, Barents, Bering and Okhotsk alongside the Greenland Sea. While I don't doubt everything is connected in the Arctic, I do doubt how much of an effect the Siberian seas now have on these peripheral seas in March. The current Siberian delay is deeply concerning as is and will cause lots of damage locally and across the CAB (due to trans polar drift) but I wouldn't go as far as extending the damage to open water in March soaking up sun.
Title: Re: The 2020/2021 freezing season
Post by: uniquorn on October 25, 2020, 11:16:46 AM
Here is the Oct 23rd situation. Panoply makes a quite decent no-click map out of GHRSST data with a little help from AMSR2_AWI, OsiSaf and Gimp.
20201023000000-OSPO-L4_GHRSST-SSTfnd-Geo_Polar_Blended_Night-GLOB-v02.0-fv01.0.nc
An excellent combination.

IABP raw data is available in the format shown below. The map (https://iabp.apl.uw.edu/maps_daily_map.html) shows the locations and the data can be looked up using the table (https://iabp.apl.uw.edu/maps_daily_table.html)

iabp204672 204762 is shown below. The default scales are large but you can create your own chart from the data.
Title: Re: The 2020/2021 freezing season
Post by: Aluminium on October 25, 2020, 11:48:12 AM
Temperature on Kotelny Island finally falls below -10°C. Winter is coming.
Title: Re: The 2020/2021 freezing season
Post by: uniquorn on October 25, 2020, 12:46:16 PM
IABP buoy drift and surface temperature update. A steady drift along the line from Chukchi to Fram since oct6 until recently. My buoy list needs updating since it doesn't appear to include 204672 above. (12MB is a bit large) edit: updating this updated below

Unrelated but also interesting is the amount of heat escaping from the Nth Greenland Coast. https://go.nasa.gov/2HxW0GH

amsr2 awi v103, oct14-24
click for animations.

polarview S1B
Title: Re: The 2020/2021 freezing season
Post by: Freegrass on October 25, 2020, 01:52:41 PM
Latest Five Day Forecast
Wind + Temp @ Surface
Large GiF!
Title: Re: The 2020/2021 freezing season
Post by: A-Team on October 25, 2020, 01:56:51 PM
Quote
Winter is finally here, Kotolny Island is really cold!
No it isn't. The quite moderate 10 day forecast is attached below. The icons indicate extent of cloud cover which affect radiative balance. The weather station reports 2m temperatures but those are relative to its elevation of 8m above sea level.

http://www.aps-polar.org/mv_html/j00001/2015-02/20150206_APS.htm congelation land-fast ice

While ECMWF and GFS assimilate this station in their regional forecasts (and CR in turn), it's not at all clear which hPa over the Laptev (925? boundary layer?) is most relevant to the cold experienced by open water (near-surface air is somewhat clamped to surface water temperature).

GFS is currently reporting air temperatures of -4.5, -4.7, -15.9 at the surface, 1000 hPa, 850 hPa respectively at UTC noon today. These bear no immediate relationship to highs or lows at Kotolny (-12. -7).
Quote
Can buoys in Laptev validate or improve on SST measurement
That 204672 buoy is in a good location but it does not currently appear in IADP's table!
https://iabp.apl.uw.edu/TABLES/ArcticTable.php

However 204761 and 204762 do: these are global drifters of type SVP-B, placed by AARI-USIABP (Russian Arctic and Antarctic Research Institute joint US Interagency Arctic Buoy Program). The former is at 75.23 114.88 on 10/25/2020 measuring water temperature at the bottom of the buoy at 0.96ºC. The latter is at 76.78 118.34 showing 1.68ºC.

It seems like 204763 and 204764 are also worthy of consideration. These are at 76.70 111.48 showing -1.68ºC and 79.90 121.38 seeing -0.80ºC. Uniq has picked these up in #538 below.

"These SVP (surface velocity drifters) were standardized in 1991 with small spherical hull, floats and large Holey-Sock drogues 15m below the surface. In 1993, drifters with barometer ports, called SVPB drifters measure sea surface currents, sea surface temperature baryometric pressure and lat/lon."

The hourly data is in .dat format which opens as tab-ready row & column in any text editor. It uses day number instead of dates: 299 is today Oct 25th. The most recent 557 readings from 204761 average 1.36ºC with a range of 0.58 to 4.08 ºC and stdev of 0.97, that is, the buoy has not seen any temperatures below zero and has mostly been around 1.4±1.0 ºC during its drift.
Quote
Do direct buoy measurements provide an independent check on the daily SST product from GHRSST?
More likely, the buoy data is assimilated into the product but that's unconfirmed.
Quote
Can radiative heat loss be determined from Worldview?
No. Clear weather allows that dramatic definition of heat loss leads via band 15 of Suomi VIIRS along the upper CAA. Note this is calculated from top-of-atmosphere in kelvin and is not suitable for determining overall blackbody heat loss:

"It does not provide an accurate temperature of either clouds nor the land surface, but it does show relative temperature differences which can be used to distinguish features both in clouds and in sea ice and open water over the polar regions during winter (in cloudless areas).... The sensor resolution is 375m, the imagery resolution is 250m, and the temporal resolution is daily."
Quote
How unusual is the current pattern of open water?
The image below calculates the frequency of open water at each position on Nov 1st for the seven years 2013-19 (this date in 2012 is not available from AMSR2_UHH). This gives the lightest gray for open water in all seven years, a slightly darker gray for open water in six of seven years and so on. The progression is fairly orderly Chukchi; the Laptev has mostly been frozen over. The pink shows areas that have never before been open on Nov 1st.

The base image is Smos-Smap ice thinness for Oct 23rd. It has an interesting green fringe of presumably nascent ice in the 2-3 cm thinness range. The interior ice thicker than 0.5m has been replaced with OsiSaf ice motion for the same date; the exterior open water has been removed to reveal the historical open water probabilities.
Title: Re: The 2020/2021 freezing season
Post by: uniquorn on October 25, 2020, 02:50:27 PM
IABP buoy drift and surface temperature update.(11MB)

closer look at iabp204761 and 204762 in the Laptev (3.5MB)
click
Title: Re: The 2020/2021 freezing season
Post by: SimonF92 on October 25, 2020, 03:03:07 PM
Building on uniquorns nice code. (current date only)
Title: Re: The 2020/2021 freezing season
Post by: uniquorn on October 25, 2020, 03:28:53 PM
Thanks SimonF92. Animation scope widened to include the 2 newer buoys 204763 and 204764
Looking forward to your animations
Title: Re: The 2020/2021 freezing season
Post by: BornFromTheVoid on October 25, 2020, 06:20:54 PM
Here's the sea ice forecast to the end of the month from the CMEMS NeXtSIM model. It appears to suggest a continuation of the very slow growth, mainly around the Laptev and Kara seas, with even a little loss around Chukchi.

Thomas Lavergne looked at another model which shows more significant growth overall, especially towards the ESS.
https://twitter.com/lavergnetho/status/1320340626127323136
Title: Re: The 2020/2021 freezing season
Post by: gandul on October 25, 2020, 07:13:28 PM
Just a friendly reminder that there is no proof whatsoever that what we are observing over the Laptev sea is effect of Atlantic waters.
There has been an incredible year-long blob of heat excess over the land adjacent to the Laptev sea.
There was a twenty-day long powerful GAAC in July which warmest region was exactly over the Laptev and north west of it
Weather has been very agitated in September with frequent southerlies from land over Laptev sea.
Weather has been very agitated in October with a mega-ridge that caused very strong winds and, if thermodynamics still go in the right direction, accumulated ocean heat release. The current ocean temperature excess over Laptev sea can be perfectly explained by all of the above that we have just witnessed over the months. At least that explanation seems more simple than a thermohaline staircase  collapsing etc.

The Atlantic Water effect is, as much, a hypothesis to be corroborated by future models.
Title: Re: The 2020/2021 freezing season
Post by: uniquorn on October 25, 2020, 07:22:05 PM
amsr2-awi-v103, atlantic side oct24-25. Sea ice crossing the shelf close to SZ.
Title: Re: The 2020/2021 freezing season
Post by: Jim Hunt on October 25, 2020, 08:21:14 PM
The first AWI merged CryoSat-2/SMOS thickness map of the freezing season is now available:

https://GreatWhiteCon.info/2020/10/facts-about-the-arctic-in-october-2020/

Quote
Whichever way you look at it there certainly isn't much ice on the Siberian side of the Arctic at the moment! However CryoSat-2 and PIOMAS don't seem to be able to agree on where the thickest ice in the Arctic is at the moment. It certainly isn't anywhere near the North Pole though.
Title: Re: The 2020/2021 freezing season
Post by: A-Team on October 25, 2020, 08:53:38 PM
Here is Lavergne's forecast to Nov 1st using the CMEMS GLO model. It is five days old. No links to to the forecast sites are being provided. It appears to be using the same ECMWF forcings.

https://marine.copernicus.eu/about-us/about-producers/glo-mfc/ from Mercator Ocean GLO

https://www.mercator-ocean.fr/en/portfolio/wizard/  neXtSIM

WIzArd aims at improving our understanding and modelling of the interactions between sea ice, ocean and wave at arctic ocean surface, with a particular focus on the Marginal ice Zone (MIZ). We will couple the Lagrangian sea ice model, neXtSIM, with an ocean model (NEMO) and wave model (WAVEWATCH III), using the configuration CREG12 previously developed for CMEMS. The novelty of neXtSIM lies within its ability to better reproduce the sea ice mechanical properties, as well as the interplay between sea ice and waves propagating into the sea ice pack.

A link to the neXtSIM forecast seems to be implicit in CMEMS sea ice fraction forecast to Oct 31st but until Lobelia gets image and time series downloads going next month, it seems necessary now to tediously step through the dates. It seems that none of the 12 CMEMS sea surface temperature products provide complementary companion forecasts, ie they don't go out beyond the 24th. The second image is a mixed-date composite.

https://t.co/JSBMKl00Nm?

Wave–ice interactions in the neXtSIM sea-ice model
TD Williams,P Rampal S Bouillon 7 Sep 2017
https://tc.copernicus.org/articles/11/2117/2017/tc-11-2117-2017.pdf

In this paper we describe a waves-in-ice model (WIM), which calculates ice breakage and the wave radiation stress (WRS). This WIM is then coupled to the new sea-ice model neXtSIM, which is based on the elasto-brittle (EB) rheology.

We highlight some numerical issues involved in the coupling and investigate the impact of the WRS  and of modifying the EB rheology to lower the stiffness of the ice in the area where the ice has broken up (the marginal ice zone or MIZ).

In experiments in the absence of wind, we find that wind waves can produce noticeable movement of the ice edge in loose ice (concentration around 70 %) – up to 36 km, depending on the material parameters of the ice that are used and the dynamical model used for the broken ice. The ice edge position is unaffected by the WRS if the initial concentration is higher (& 0.9).

Swell waves (monochromatic waves with low frequency) do not affect the ice edge location (even for loose ice), as they are attenuated much less than the higher-frequency components of a wind wave spectrum, and so consequently produce a much lower WRS by about an order of magnitude. In the presence of wind, we find that the wind stress dominates the WRS which while large near the ice edge decays exponentially away from it. This is in contrast to the wind stress, which is applied over a much larger ice area."
Title: Re: The 2020/2021 freezing season
Post by: Sepp on October 25, 2020, 09:03:21 PM
The first AWI merged CryoSat-2/SMOS thickness map of the freezing season is now available:

https://GreatWhiteCon.info/2020/10/facts-about-the-arctic-in-october-2020/

Great, I am looking forward to calculate the total volume with your (?) script tomorrow.  :)
Title: Re: The 2020/2021 freezing season
Post by: gandul on October 25, 2020, 09:12:31 PM
The first AWI merged CryoSat-2/SMOS thickness map of the freezing season is now available:

https://GreatWhiteCon.info/2020/10/facts-about-the-arctic-in-october-2020/

Quote
Whichever way you look at it there certainly isn't much ice on the Siberian side of the Arctic at the moment! However CryoSat-2 and PIOMAS don't seem to be able to agree on where the thickest ice in the Arctic is at the moment. It certainly isn't anywhere near the North Pole though.
Right, PIOMAS and Cryosat-2 do not agree. Observations, that is Cryosat-2, find pretty thick ice in the near 1.5 million km2 region of Western CAB where the NASA/NSIDC Lagrangian model finds 3 and 4+ year old ice. According to A-Team, that region between the Pole and Beaufort does not drift really fast, usually takes its time to go either way, so that most of thar ice ain’t going nowhere in 2021 and probably 2022 (unless it melts out which is very very much improbable given that it doesn’t since 2016).

If it was at the Pole, you are right it isn’t, it could go down the Fram drain by next April.
Title: Re: The 2020/2021 freezing season
Post by: A-Team on October 25, 2020, 10:10:22 PM
Quote
The first AWI merged CryoSat-2/SMOS thickness map of the freezing season
The thickest ice on that image is 2.56m, the top range is boxed in black below and shown better in #550. The white outline is the ice between 0.5 and 1.0 which is just beyond Smos/Smap thickness reliability limits. The palette is really bad at the low end so it has been replaced below with brighter colors. The archival Smos-Smap thinness map of the 23rd is shown below that at the same scale.

It takes many orbits of the CryoSat2 satellite to observe the freeboard because its swath is so narrow. By that time of course the ice has had more time to thicken on the earlier swaths so the product is not even quasi-isochronous in the manner of daily SMOS thinness. However it is observational unlike Piomas and the Smos component has addressed its weakest components. There would not be issues with the snowpack yet or lingering meltponds.

Freeboard is still several assumptions away from ice thickness, namely buoyancy (density), presumption of buoyant equilibrium, state of brine exclusion, condition/definition of ice bottom and so on.

It's not easy to compare Piomas (which has a its own complicated history of production and goofy pixel griding) with this product. Both need to be put in netCDF for array subtraction but so far it seems only cryo2smos has been. There the lat line graticules could be shut off that currently disrupt comparison. On twitter, one ice expert opined that the agreement was excellent, only differing by 0.5m. That's actually terrible on a percentage error basis, like applauding a dog walking awkwardly on its hind legs.

The sea ice age product 'gives the idea' but is very rough (how can they track floes accurately over the summer?!?) and thus unsuitable for comparison to either of these. We have no idea at this point how much CAB ice will be sent how far up the Beaufort Arm nor whether the TransPolar Drift will set in nor at what width.

We're definitely getting deeper into uncharted waters on the Siberian side. It's better just to wait and see how it plays out, not waste effort on a few days of forward prediction. No one saw this coming even by mid-September, no one knows where it will end, no one can say what specific downstream consequences will follow.

Multiple scientific teams are drafting up papers as we speak, articles will be finalized the day the Laptev freezes over and submitted shortly thereafter, just like what happened with GAAC 2012 (Simmons 2012) or the 2018 Fram cyclone (Boisvert 2018).

GlennK suggested several interesting things in #527 that could be done now, the easiest of which is setting up a daily refresh for SSTfnd velocity-of-cooling, apportioning the heated water between long-term atlantification and a big solar insolation summer coupled with Siberian heat wave.

Inverting that to get at the reanalyzed atmosphere's contribution to the so far inadequate energy flux is really the key to nailing down the many adjustable parameters in these coupled models. We could probably use CR and TPW to pick the low hanging fruit but the models themselves can't be run from online portals.
Title: Re: The 2020/2021 freezing season
Post by: oren on October 25, 2020, 10:39:30 PM
Thank you A-Team. I find the original C2S palette quite unreadable.
Title: Re: The 2020/2021 freezing season
Post by: Jim Hunt on October 25, 2020, 11:10:57 PM
I am looking forward to calculate the total volume with your (?) script tomorrow.  :)

Well yes, albeit with much assistance from Wipneus and Stefan Hendricks.

I look forward to seeing your results!
Title: Re: The 2020/2021 freezing season
Post by: uniquorn on October 26, 2020, 12:14:44 AM
1 day difference
ftp://ftp.awi.de/sea_ice/product/cryosat2_smos/v203/nh/LATEST
Title: Re: The 2020/2021 freezing season
Post by: A-Team on October 26, 2020, 12:27:57 AM
Quote
the original C2S palette is quite unreadable
The auto-archive has been created by L Kaleschke of AWI who sometimes posts here and on twitter. The files are updated daily using the updated Smos and whatever Cryo swaths that have come in. The day to day differences are small but can be visualized either by differencing the pngs or by visualizing the (perfectly done) netCDF in Panoply.

The combining algorithm parts are complex and have been under intensive development for years. Kaleschke spent four months on the Polarstern; one of the main objectives there was to synch plane and satellite overflights with myriad ice cores to improve products such as this and AMSR2. This can't be said about Piomas.

The first quickie below is contoured for major and minor scale ticks. Note the lat lon graticule is gone and the image is in 'Greenland down' orientation. The second emphasizes the thicker ice, there is very little thicker than a 1.0m this early in the freeze season and only a tiny bit near the 2.56m maximum. The third displays thickness isopleths.

No script is needed for the volume calc in an equal area pixel projection like lambert azimuthal. It's a menu item in ImageJ. It takes another click or two in Excel to graph the distribution of ice thickness (which is likely normal about the mean but skewed against thicker ice without notable kurtosis).

The main .nc files here are a great opportunity to learn about graphical display and analysis of netCDF data using painless Panoply.

https://www.giss.nasa.gov/tools/panoply/download/   easy stable netCDF menu-driven tool
https://imagej.nih.gov/ij/download.html  free scientific graphics tool

ftp://ftp.awi.de/sea_ice/product/cryosat2_smos/v203/nh/LATEST/  home folder

ftp://ftp.awi.de/sea_ice/product/cryosat2_smos/v203/nh/LATEST/W_XX-ESA,SMOS_CS2,NH_25KM_EASE2_20201017_20201023_o_v203_01_l4sit.png

ftp://ftp.awi.de/sea_ice/product/cryosat2_smos/v203/nh/LATEST/W_XX-ESA,SMOS_CS2,NH_25KM_EASE2_20201017_20201023_o_v203_01_l4sit.nc
Title: Re: The 2020/2021 freezing season
Post by: jdallen on October 26, 2020, 02:10:51 AM
Quote
the original C2S palette is quite unreadable
<snip>
The quickie below is contoured for major and minor scale ticks. Note the lat lon graticule is gone and it is in 'Greenland down' orientation. The second emphasizes the very thickest ice, there is a tiny bit at 2.56m.
<snip>
This may be the most depressing image I've ever seen on these forums.

It suggests all the land fast ice is gone, for practical purposes.

It suggests all of the 3m+ ice is gone, similarly.

The pack is completely unhinged and at the full mercy of the weather.
Title: Re: The 2020/2021 freezing season
Post by: FishOutofWater on October 26, 2020, 03:09:18 AM
Gandul, there are many papers that discuss the Atlantic water layer and the increasing Atlantification of the Eurasian side of the Arctic. Google is your friend and I have given references to some articles in the past. The high salinity water in the Mercator model along the continental shelf margin in the Laptev sea has no other possible source than the north Atlantic if that high salinity water actually exists. The Coriolis effect tends to turn water to the right in the northern hemisphere except when there is a sea surface height gradient or pressure gradient in the opposite direction. There's no Pacific water layer in the Laptev sea and the Siberian shelf water has fresh water from the Siberian rivers.

I don't understand physical oceanography very well, but this is very simple geochemistry. High salinity is a dead give away that the water is of Atlantic origin.

The enhanced heat loss this fall and winter will cause an increase in mixing which will likely decrease stratification in the Laptev sea. All other variables held constant this will increase Atlantification and the sinking of saline water to mid ocean levels along the Laptev shelf margin. Of course, large scale shifts in the winds and weather could cause something else to happen.
Title: Re: The 2020/2021 freezing season
Post by: jdallen on October 26, 2020, 06:30:54 AM
I don't understand physical oceanography very well, but this is very simple geochemistry. High salinity is a dead give away that the water is of Atlantic origin.
Salinity is a key indicator, along with the documented invasion of Atlantic fauna and algae northwards and eastwards out of the Norwegian sea.

It is happening now, probably has been for over a decade.  I don't think it's theoretical any more.
Title: Re: The 2020/2021 freezing season
Post by: Aluminium on October 26, 2020, 07:41:31 AM
October 21-25.

2019 (https://forum.arctic-sea-ice.net/index.php/topic,2888.msg234350.html#msg234350).
Title: Re: The 2020/2021 freezing season
Post by: aslan on October 26, 2020, 08:22:03 AM
Temperature on Kotelny Island finally falls below -10°C. Winter is coming.

Not wanting to sound disparaging, but -10°C at Kotel'nyj at this time of year is barely the normal high, and temperatures are already back to -2°C :

http://ogimet.com/cgi-bin/gsynres?ind=21432&decoded=yes&ndays=20&ano=2020&mes=10&day=26&hora=12

Of course it is cooling. Even with all the warming possible, October is bound to be a month of rapid decline of the temperatures in  the NH. But anomalies are still extreme and the seasonal cooling not so strong. Even though we are not going to see a repeat of the month of Septemebr, with monthly mean temperatures higher than the preceding records by many °C over millions of square kms ; October is still going to book new records. As of now for exemple, mean temp' at Kotel'Nyj is -2.8°C and the record is -3.2°C in 2018. We will need more than one or two "mornings"(ok, Tn  ;D ) at -10°C for not breaking the record.
Title: Re: The 2020/2021 freezing season
Post by: idunno on October 26, 2020, 08:50:08 AM
Hi all,

Its been some time, and I havent been regularly following...

When I was often contributing here, I'd argue that the summer minima were not the most serious indicator, and that a failure of the refreeze, which raises the SST from -30C or thereabouts (ice) to -1.8C (water) would have a much more dramatic effect on the atmosphere. That seems to be afoot.

I am well out of my depth with data-handling and graphing, but I'd like to throw out there that the most useful graph that could be produced in the current extraordinary conditions would be one showing the total ice extent area as an average over the preceeding 365 days, on any particular day for which we have data.

Perhaps it may be more practical to pick the first day of each month. Either way, I'm fairly sure that the lowest reading would be the last one, and this would hold the record only until the next one becomes available.

I think this might be helpful for the general public, for them to appreciate the current dire state of affairs.

(If this has been graphed already, please excuse my current state of ignorance)

cheers,

idunno
Title: Re: The 2020/2021 freezing season
Post by: oren on October 26, 2020, 09:14:24 AM
idunno, this has already been covered, please check this thread
https://forum.arctic-sea-ice.net/index.php/topic,2909.0.html (https://forum.arctic-sea-ice.net/index.php/topic,2909.0.html)
Our "old faithful" Gerontocrat is updating the chart frequently, based on data from the most recent 365 days. The record is still held by March-April 2017, but we may have a good chance of breaking it.
Title: Re: The 2020/2021 freezing season
Post by: Sepp on October 26, 2020, 09:22:52 AM
I look forward to seeing your results!

These are the results of your script (I did not have time, to use the other approach suggested by A-Team):

Arctic on 20201022 - Volume = 4627.1 km³, Uncertainty = 715.0 km³
With 15.0% threshold - Area = 4508628.4 km², Extent = 5413750.0 km²
Arctic on 20201023 - Volume = 4636.8 km³, Uncertainty = 713.3 km³
With 15.0% threshold - Area = 4572533.6 km², Extent = 5473125.0 km²

So this would give 400 to 500 km³ less than Piomas Mid October numbers. Actually quite closer than I expected.
Title: Re: The 2020/2021 freezing season
Post by: oren on October 26, 2020, 09:52:57 AM
Thanks Sepp. Do you know what was the difference with PIOMAS in April, before C2S stopped providing data?
Title: Re: The 2020/2021 freezing season
Post by: aslan on October 26, 2020, 10:29:55 AM
Big waves are again forecasted for the siberian side. Strong winds are usual at this time of the year, but the fetch should be zero or almost zero. Here, winds are blowing over open water. As a consequences, waves of 4 - 6 meters with a period of 8 - 10 seconds for Chukchi and Kara sea... A good washing again.
Title: Re: The 2020/2021 freezing season
Post by: Sepp on October 26, 2020, 10:45:03 AM
Thanks Sepp. Do you know what was the difference with PIOMAS in April, before C2S stopped providing data?

According to figure 10 on the PIOMAS site (http://psc.apl.washington.edu/research/projects/arctic-sea-ice-volume-anomaly/) it was roughly around 5000 km³ or 20 percent below the PIOMAS value, while currently its only around ten percent. But the dates do not match exactly, so those values are a bit ambigous, I think and even with this slow freezing, the difference of one week might be quite significant. I’d expect PIOMAS releases their own comparison chart with the final October report. Those numbers might give a better picture than mine.
Title: Re: The 2020/2021 freezing season
Post by: Pagophilus on October 26, 2020, 11:22:43 AM
NSIDC comparison tool.  Oct 24 2020 ice extent vs Oct 24 2019, 2016, 2012.
Title: Re: The 2020/2021 freezing season
Post by: SimonF92 on October 26, 2020, 11:38:35 AM
NSIDC comparison tool.  Oct 24 2020 ice extent vs Oct 24 2019, 2016, 2012.

Very nice. A clear demonstration.
Title: Re: The 2020/2021 freezing season
Post by: Freegrass on October 26, 2020, 12:48:38 PM
Latest Five Day Forecast
Wind @ Surface + Total Precipitable Water
Wind + Temp @ 850hPa
Wind @ 250hPa
Large GiFS!
Title: Re: The 2020/2021 freezing season
Post by: Pavel on October 26, 2020, 12:57:05 PM
Well, at least there is no strong heat advection to the high Arctic. But this pattern was the entire last freezing season and has resulted the low snow cover in Eurasia by the end of winter and abnormal Siberian heat in spring
Title: Re: The 2020/2021 freezing season
Post by: Aluminium on October 26, 2020, 02:00:19 PM
This winter I would not be surprised to see heat advection from the Arctic.
Title: Re: The 2020/2021 freezing season
Post by: Shared Humanity on October 26, 2020, 03:00:05 PM
Big waves are again forecasted for the siberian side. Strong winds are usual at this time of the year, but the fetch should be zero or almost zero. Here, winds are blowing over open water. As a consequences, waves of 4 - 6 meters with a period of 8 - 10 seconds for Chukchi and Kara sea... A good washing again.

Hard for ice to form in seas with 4 meter waves. How deep does the mixing of water occur in such seas?
Title: Re: The 2020/2021 freezing season
Post by: Général de GuerreLasse on October 26, 2020, 03:09:30 PM
Big waves are again forecasted for the siberian side. Strong winds are usual at this time of the year, but the fetch should be zero or almost zero. Here, winds are blowing over open water. As a consequences, waves of 4 - 6 meters with a period of 8 - 10 seconds for Chukchi and Kara sea... A good washing again.

Hard for ice to form in seas with 4 meter waves. How deep does the mixing of water occur in such seas?

The average wave period does not seem high to me, except in the Barents Sea. It may not be enough to mix the water in depth? I am not a specialist.
Title: Re: The 2020/2021 freezing season
Post by: aslan on October 26, 2020, 03:28:54 PM
This is Arctic. Even though on its own a wave period of 10 seconds is not extraordinary (in the Pacific, period of 20 seconds are possible...), it is not the way it must work. For the depth of the mixing, I don't know and I am not sure there can be an answer. It depends on different factors, and especially the stratification of ocean. During the storm of 2012, mixing occurs over a depth of about 10 to 30 meters : https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1002/grl.50190. And during a storm in October 2015, it was about the same idea : https://agupubs.onlinelibrary.wiley.com/doi/10.1002/2018JC013764
But it is really hard to give some numbers. It depends a lot on the stratification of the ocean. Either way, even though it does not sound a lot, wave period of 10 seconds and mixing depth of 30 meters are really significant in the Arctic.

P.S. : Worth to read also :https://reader.elsevier.com/reader/sd/pii/S1463500316300622?token=DFCB8444FB3423422C3C831531FD0FB4704E87BCAFBCCEF5681DA1C00B8EDCDAE777B94E618EBCD0F4333143CEB831D5

(but there is also the question of the reduced stratification of the atmosphere which should promote higher wind speed at surface, no matter the change in the pressure field. I am not aware of anay studies about this subject)
Title: Re: The 2020/2021 freezing season
Post by: aslan on October 26, 2020, 04:47:55 PM
Quick and dirty sorry, but about the storm of tomorrow, to illustrate again. Map is wind speed (orange and yellow) at 500m (about 925 hPa), wind at same height (I hope...), theta (potential temperature) in black, surface temperature at -2°C in blue for an approximate ice edge, vertical velocity at 925 hPa (max threshold at -10 Pa/s) in gray and convective rainfall in transparence. And when I say convective rainfall, yeah I really meant that models are forecasting CBs all over the Arctic in the coming day. Next step, a subtropical storm in the Arctic.... This said. If we follow the wind, we hit a wall of theta which is the inversion over sea ice. There is surface based CAPE north to Kotel'Nyj (For central Arctic in late October, this qualify as a "holy mother of Einstein, what the f*** is going on" level on the crazyometer). This layer of unstable air is forced to rise over the ridge of theta, bringing mid level CBs over ice pack. We are swimming in a pool of craziness. This advection can be followed on soundings as the theta at the top of the inversion is the same that theta at surface north of Kotel'Nyj. We really have an isentropic lift forced by the temperature inversion over the pack, forcing ascents and instability... And on top of that, we can see that LLJ can't descend to surface over ice pack.
Soundings are from south to north (77°N, 81°N, 82°N)
Of course there is also and mostly synoptic scale forcings, etc... but there is really some things going on at the interface between sea ice and ocean, and we are to the point we need a good swath of CBs to cool down the Arctic Ocean. On top of that, in the Arctic night, CBs are powerfull at isolating the surface, radiating a lot of heat toward he surface in longwave (and sea ice is not white in IR...)
Title: Re: The 2020/2021 freezing season
Post by: aslan on October 26, 2020, 04:52:35 PM
Last sounding
Title: Re: The 2020/2021 freezing season
Post by: Général de GuerreLasse on October 26, 2020, 05:19:59 PM
This is Arctic. Even though on its own a wave period of 10 seconds is not extraordinary (in the Pacific, period of 20 seconds are possible...), it is not the way it must work. For the depth of the mixing, I don't know and I am not sure there can be an answer. It depends on different factors, and especially the stratification of ocean. During the storm of 2012, mixing occurs over a depth of about 10 to 30 meters : https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1002/grl.50190. And during a storm in October 2015, it was about the same idea : https://agupubs.onlinelibrary.wiley.com/doi/10.1002/2018JC013764
But it is really hard to give some numbers. It depends a lot on the stratification of the ocean. Either way, even though it does not sound a lot, wave period of 10 seconds and mixing depth of 30 meters are really significant in the Arctic.

P.S. : Worth to read also :https://reader.elsevier.com/reader/sd/pii/S1463500316300622?token=DFCB8444FB3423422C3C831531FD0FB4704E87BCAFBCCEF5681DA1C00B8EDCDAE777B94E618EBCD0F4333143CEB831D5

(but there is also the question of the reduced stratification of the atmosphere which should promote higher wind speed at surface, no matter the change in the pressure field. I am not aware of anay studies about this subject)

A big thank you to you Aslan, the link you have given is exciting. I think I'll have to read and reread it to understand it, but the extract I propose here is enlightening. You were right, I suspected it a little bit  ;D but here I have a good explanation that I will dig.

"The autumn storms that regularly occur in the Beaufort and Chukchi Seas are elevating the sea state now, and will continue so into the future, simply because it is increasingly likely that the storms will occur over larger open water areas that persist longer into autumn. It is yet to be determined if the higher sea states will in turn feed back to the large-scale evolution of the sea ice. The increasing sea state may affect not only the ice cover development, but also wave forcing in the coastal zone. Either way, the increasing sea states may alter air-sea fluxes and associated ecosystem processes. It is possible that the increasing sea state may play an important role in modulating the presumed changes in air-sea fluxes and upper ocean properties that are occurring, and in turn may modulate the response of sea ice to climate change."
Title: Re: The 2020/2021 freezing season
Post by: BornFromTheVoid on October 26, 2020, 05:50:25 PM
Here's a side by side comparison of the first 25 days of ice growth this October compared to 2012
(Larger, better quality version on twitter here: https://twitter.com/Icy_Samuel/status/1320764047638302720)

Title: Re: The 2020/2021 freezing season
Post by: Milwen on October 26, 2020, 06:56:37 PM
https://twitter.com/R34lB0rg/status/1320758721929248768/photo/1  :o
Title: Re: The 2020/2021 freezing season
Post by: Niall Dollard on October 26, 2020, 09:01:04 PM
Yes Milwen. This evening's ECMWF op run has substantial warmth flooding the eastern half of the Arctic at the end of the run. Still 10 days away so at the end of the medium range.

Negative Arctic dipole.
Title: Re: The 2020/2021 freezing season
Post by: jdallen on October 26, 2020, 11:36:04 PM
Yes Milwen. This evening's ECMWF op run has substantial warmth flooding the eastern half of the Arctic at the end of the run. Still 10 days away so at the end of the medium range.

Negative Arctic dipole.
... and the same level of astounding temperature anomalies we saw in 2016, and to a lesser degree later, except, perhaps, worse.
Title: Re: The 2020/2021 freezing season
Post by: uniquorn on October 26, 2020, 11:46:04 PM
cs2smos thickness difference, oct23-25.
Guessing that blue spot must be bathy related.
Title: Re: The 2020/2021 freezing season
Post by: Gumbercules on October 27, 2020, 03:20:08 AM
Big waves are again forecasted for the siberian side. Strong winds are usual at this time of the year, but the fetch should be zero or almost zero. Here, winds are blowing over open water. As a consequences, waves of 4 - 6 meters with a period of 8 - 10 seconds for Chukchi and Kara sea... A good washing again.

Hard for ice to form in seas with 4 meter waves. How deep does the mixing of water occur in such seas?

The average wave period does not seem high to me, except in the Barents Sea. It may not be enough to mix the water in depth? I am not a specialist.

Wouldn't a lower period result in more mixing? Higher period means lower frequency, longer wavelength wave, so a smoother ocean. Lower period means high frequency, meaning shorter wavelengths, meaning more turbulent ocean.

This is just my initial analysis based on intuition.
Title: Re: The 2020/2021 freezing season
Post by: A-Team on October 27, 2020, 11:53:52 AM
Quote
bathymetry --> ice thinning spot?
Thousands of meters deep, tectonically quiet, nothing down there for a heat or turbulence source?

Whenever something is measured in physics, there's an obligation to estimate the error. In the Cryo2Smos netCDFs, there is indeed an included Geo2D file that generates the error map. Subtracting two close dates will lead to more combined error. If this error is too high relative to bona fide data differences, interpretation becomes problematic.

The error map seems to have a hot spot at the blue anomaly above. Here it might be worth clicking over to array view and looking at the patch of numbers for the nature of the oddity. It is more likely to originate from the Cryo than from the SMOS.

The ice thickness time series here only will only get to day 4 this afternoon. So the opportunities for limiting subtraction error will improve, from day2-day1, day3-day1 (above), day4-day1 etc and at some point will become relatively negligible in comparison to data differences.

As weeks and months of data become available, sufficiently separated date pairs can determine a ice thickening rate map across the lower Arctic. Note reducing the map to a single volume number loses all these important regional differences.

On the open water side, still 40% of the Arctic surface, the counterpart to the ice thickness netCDF is a high quality daily netCDF for 'foundational' sea surface temperature, the mixed layer at 10m. That archive goes back for many months but here the interest is how fast the water column temperature has been cooling during the freeze season to estimate when it will become cold enough to freeze over. Again a nuanced regional (map) basis is preferable to a single extent number.

There is no single reason that explains the late freeze-up this year. Instead, the observed heat built up in the water column over time has to be apportioned among the various sources and balanced against mechanisms of heat loss. Inputs include global climatic trends and tele-connections, Arctic Amplification, creeping Atlantification, clear skies and summer insolation of open water, Siberian heat waves, mid-latitude moisture intrusions, cyclones, wave mixing, cooling buoyancy induced turbulence and so on. Outputs, mechanisms by which the water column loses heat, have been discussed earlier. Right now, the air is too warm and wind mixing to depth too high but those are acting on a heat state attained via earlier effects.

"The Arctic sea ice is growing very slowly this year. The ocean temperature in the entire mixed layer has to drop below the freezing point because the sea water is salty: when it cools down, the density increases and this leads to [buoyancy-driven] convection as it sinks. The lack of new ice growth is [quite anomalous]. SMOS shows an exceptionally small [advance] area covered with thin ice." Fig 3 Fig 4 https://twitter.com/seaice_de

The main difficulty in using Panoply to make time or difference series is in setting the range to accommodate the earliest and latest dates. If too broad, data will be squeezed into a narrow portion of the color range, losing resolution; too narrow, outlying but differing data will lumped into the end points.

Although Panoply offers over a hundred palettes, it may be best just to use the 255-grayscale where subtraction of pixels means what you want it to mean, subtraction of data values. (Images are spreadsheets.) Then colorize the final product later using one of the thousands of LUTs available in ImageJ, with custom adjustment wherever colors are not visually distinguishable.

The key is looking at product histograms of data value scatter and their asymmetry. The latter can be seen by superimposing a horizontal flip on a fast rocker.
Title: Re: The 2020/2021 freezing season
Post by: uniquorn on October 27, 2020, 12:13:23 PM
Big waves are again forecasted for the siberian side. Strong winds are usual at this time of the year, but the fetch should be zero or almost zero. Here, winds are blowing over open water. As a consequences, waves of 4 - 6 meters with a period of 8 - 10 seconds for Chukchi and Kara sea... A good washing again.
Hard for ice to form in seas with 4 meter waves. How deep does the mixing of water occur in such seas?

An essay from Peter Wadhams 2003  How Does Arctic Sea Ice Form and Decay? (https://www.pmel.noaa.gov/arctic-zone/essay_wadhams.html)
Quote
How ice forms in rough water
If the initial ice formation occurs in rough water, for instance at the extreme ice edge in rough seas such as the Greenland or Bering Seas, then the high energy and turbulence in the wave field maintains the new ice as a dense suspension of frazil, rather than forming nilas. This suspension undergoes cyclic compression because of the particle orbits in the wave field, and during the compression phase the crystals can freeze together to form small coherent cakes of slush which grow larger by accretion from the frazil ice and more solid through continued freezing between the crystals. This becomes known as pancake ice because collisions between the cakes pump frazil ice suspension onto the edges of the cakes, then the water drains away to leave a raised rim of ice which gives each cake the appearance of a pancake. At the ice edge the pancakes are only a few cm in diameter, but they gradually grow in diameter and thickness with increasing distance from the ice edge, until they may reach 3-5 m diameter and 50-70 cm thickness. The surrounding frazil continues to grow and supply material to the growing pancakes.

At greater distances inside the ice edge, where the wave field is calmed, the pancakes may begin to freeze together in groups and eventually coalesce to form first large floes, then finally a continuous sheet of first-year ice known as consolidated pancake ice. Such ice has a different bottom morphology from normal sea ice. The pancakes at the time of consolidation are jumbled together and rafted over one another, and freeze together in this way with the frazil acting as "glue". The result is a very rough, jagged bottom, with rafted cakes doubling or tripling the normal ice thickness, and with the edges of pancakes protruding upwards to give a surface topography resembling a "stony field".

This open access article from Nature covers winter storms in much greater detail, describing both positive and negative effects on ice growth.

Winter storms accelerate the demise of sea ice in the Atlantic sector of the Arctic Ocean (https://www.nature.com/articles/s41598-019-45574-5)
Robert M. Graham, Polona Itkin, […]Mats A. Granskog    25 June 2019
Quote
Abstract
A large retreat of sea-ice in the ‘stormy’ Atlantic Sector of the Arctic Ocean has become evident through a series of record minima for the winter maximum sea-ice extent since 2015. Results from the Norwegian young sea ICE (N-ICE2015) expedition, a five-month-long (Jan-Jun) drifting ice station in first and second year pack-ice north of Svalbard, showcase how sea-ice in this region is frequently affected by passing winter storms. Here we synthesise the interdisciplinary N-ICE2015 dataset, including independent observations of the atmosphere, snow, sea-ice, ocean, and ecosystem. We build upon recent results and illustrate the different mechanisms through which winter storms impact the coupled Arctic sea-ice system. These short-lived and episodic synoptic-scale events transport pulses of heat and moisture into the Arctic, which temporarily reduce radiative cooling and henceforth ice growth. Cumulative snowfall from each sequential storm deepens the snow pack and insulates the sea-ice, further inhibiting ice growth throughout the remaining winter season. Strong winds fracture the ice cover, enhance ocean-ice-atmosphere heat fluxes, and make the ice more susceptible to lateral melt. In conclusion, the legacy of Arctic winter storms for sea-ice and the ice-associated ecosystem in the Atlantic Sector lasts far beyond their short lifespan.

<>

Winter storms enhance ocean mixing, heat fluxes, and ice melt
Sea ice dampens energy transfers between the atmosphere and ocean, and therefore the Arctic Ocean is traditionally considered to be energetically ‘quiet’ with weak turbulent mixing58. However, strong winds during the N-ICE2015 winter storms enhanced ice drift speeds54 (Figs 3a and 5a), which increased ocean-ice velocity shear59. These processes were found to generate mixing in the upper ocean, and led to increased transfer of ocean heat towards the ice59,60 (Fig. 5c–e). Observed winter ocean-ice heat fluxes typically more than tripled from 2 W m−2 to 7 W m−2 during storm periods (Fig. 5c, Methods), further impeding ice growth and in several cases initiating bottom melt59,60 (Fig. 3b).

Ocean mixing is particularly important in many regions of the Arctic Ocean because warm water of Atlantic origin is located below cold and fresh Polar Surface Water61. Along the continental slope north of Svalbard, warm Atlantic Water (>2 °C) is found close to the surface (Figs 1, 5e). Vertical mixing thus generates enhanced ocean heat fluxes. The magnitude of this heat flux is dependent on the mixing rate, as well as the depth and temperature of the warm water. During the N-ICE2015 winter drift over the deep Nansen Basin, Modified Atlantic Water (>0 °C) was found at approximately 100 m depth62. Under calm conditions in the deep Nansen Basin, Meyer et al.60 observed ocean heat fluxes at the pycnocline of approximately 3 W m−2 (Fig. S1). However, during storm periods, wind-driven mixing almost doubled the pycnocline heat fluxes to 5.5 W m−2 (Methods, Fig. S4a). These enhanced ocean heat fluxes are relatively small in comparison to changes in the atmospheric surface energy budget during storms37 and were insufficient to induce ice bottom melt, but nevertheless acted to further suppress ice growth (Figs 2e and 5c). Previous work using autonomous buoy measurements have inferred enhanced ice-ocean heat fluxes during winter storms in the Beaufort Sea25. It is therefore expected that these conditions in the Nansen Basin are representative of large areas of the central Arctic Ocean.

Accepted that the water has to be cold enough to form frazil ice.

Thanks for the post above A-team. I'll check out the error anomaly. That area seems already identified as possible out of range results.
Title: Re: The 2020/2021 freezing season
Post by: Freegrass on October 27, 2020, 12:30:47 PM
Latest Five Day Forecast
Wind + Temp @ Surface
Large GiF!
Title: Re: The 2020/2021 freezing season
Post by: A-Team on October 27, 2020, 03:56:49 PM
Our parallel efforts with thickening ice and cooling water column netCDFs share the problem of the growing ice pack boundary. The former won't have any earlier time series data (too much water vapor for the satellite) and the latter will start to lose its value (because water temperature is no longer observable under ice and somewhat locked in).

The good news is the areas are complimentary so both can be combined in a single time series animation, perhaps colored separately to avoid confusion. Panoply has a helpful command at the bottom of the Plot menu for saving all current map settings to preferences (new default for next map) but does not have any mechanism for sharing these settings.

I currently have plot size set to 220 so the map will later crop to 500 pxl width; the scale bar will fit under it if set to 25 with tick fortran format %0f with size 6 font. The map is stereographic at -45º 90º with outer edge 65º.

The SST lower range of 271.15 causes the ice pack to be uniquely selectable (black) whereas filled corners picks up some Bering Sea and an upper range of 280 with background 255 gives all of the warm Chukchi a gray even back to Sept 15th (the problem area being off Point Hope).

After saving out png's for two dates (Sept 15h and Oct 23rd in example below), they can be compared in a blinker graphic or better, subtracted and offset by 128 pxls using 'grain extract; in Gimp which allows for the split red loss, blue gain palette called 'unionjack' in ImageJ.

This results in the (tentative) image below that shows the water column down to 10m has indeed  cooled appreciably in the 38 days between the melt minimum and Oct 23rd but not enough for -1.8 freezing. Color-picker clicking on any pixel should light up a single band on the temperature scale as there's been no dithering.

One small area in the Chukchi seems to have warmed and an area by the Lena delta may be blown out (need a smaller offset). If this had been done as array/09.15 - array/10.23 within Panoply, that would have generated a cooling scale of degrees K lost. Offset could probably be controlled with range settings.

Glen K requested a daily velocity map video of cooling rate with year-on-year anomalies. The former is just grain extract on the tile-up but requires making all the dailies; the latter isn't feasible because previous years have too much ice pack.

It would however be practical to go back far earlier in the summer as the files are there; this might give a handle on apportioning heat content gain between insolation, carry-over and Atlantification. Peak heat might only have been reached by mid-August, depending on the region.

Hopefully more forum members will engage with netCDF -- it is the standard data format in climate change and it doesn't get any easier than Panoply.

The final image makes a 'prediction' for the freeze-over date for the Laptev. The image takes a copy of the blue line from 2012, colors it gold and moves it over exactly horizontally until it extends the most recent 2020 date. A dotted green line is then dropped from the intercept down to the calendar date, intercepting it in late November, almost a full month later than the previous record from 2012. Note the Chukchi, ESS and Kara are not included in the analysis: the former will stay partly open into January and the ESS will freeze up somewhat earlier than the Laptev.

Freeze-over could even be a week later if the dire weather forecasts in #570 and #575 come to pass. GFS-nullschool foresees temperatures in the -3.7ºC range mid-day on Nov 1st for the whole open water region, not cold enough to trigger seawater freezing.
Title: Re: The 2020/2021 freezing season
Post by: FishOutofWater on October 27, 2020, 05:43:55 PM
Holy shit.

The unprecedented ocean heat on the Siberian shelf has triggered the Siberian shelf clathrate "methane bomb".

https://www.theguardian.com/science/2020/oct/27/sleeping-giant-arctic-methane-deposits-starting-to-release-scientists-find

High levels of the potent greenhouse gas have been detected down to a depth of 350 metres in the Laptev Sea near Russia, prompting concern among researchers that a new climate feedback loop may have been triggered that could accelerate the pace of global heating.

The slope sediments in the Arctic contain a huge quantity of frozen methane and other gases – known as hydrates. Methane has a warming effect 80 times stronger than carbon dioxide over 20 years. The United States Geological Survey has previously listed Arctic hydrate destabilisation as one of four most serious scenarios for abrupt climate change.

The international team onboard the Russian research ship R/V Akademik Keldysh said most of the bubbles were currently dissolving in the water but methane levels at the surface were four to eight times what would normally be expected and this was venting into the atmosphere.
Title: Re: The 2020/2021 freezing season
Post by: interstitial on October 27, 2020, 05:56:12 PM
Thanks for the analysis/info A-team.


The green line will probably end up a week or two earlier than what you indicated.
Title: Re: The 2020/2021 freezing season
Post by: vox_mundi on October 27, 2020, 06:02:55 PM
0.2 Degrees C Locked In: Ice Loss Due to Warming Leads to Warming Due to Ice Loss: A Vicious Circle
https://phys.org/news/2020-10-ice-loss-due-vicious-circle.html

(https://media.springernature.com/lw685/springer-static/image/art%3A10.1038%2Fs41467-020-18934-3/MediaObjects/41467_2020_18934_Fig2_HTML.png)

The loss of huge ice masses can contribute to the warming that is causing this loss and further risks. A new study now quantifies this feedback by exploring long-term if-then scenarios. If the Arctic summer sea ice were to melt completely, a scenario that is likely to become reality at least temporarily within this century, this could eventually add roughly 0.2 degrees C to global warming. It is, however, not in addition to IPCC projections of future warming, since these already take the relevant mechanisms into account. Still, the scientists have now separated the effects of the ice loss from other effects and quantified it.

The 0.2 degrees C rise is substantial, given that global mean temperature is currently about one degree higher than in pre-industrial times, and governments worldwide have agreed to stop the increase well below two degrees.

"This is not a short-term risk. Earth's ice masses are huge, which makes them very important for our Earth system as a whole—it also means that their response to anthropogenic climate change, especially that of the ice sheets on Greenland and Antarctica, unfolds on longer timescales. But even if some of the changes might take hundreds or thousands of years to manifest, it's possible we trigger them within just a couple of decades," says Ricarda Winkelmann who leads the research group.

(https://media.springernature.com/lw685/springer-static/image/art%3A10.1038%2Fs41467-020-18934-3/MediaObjects/41467_2020_18934_Fig1_HTML.png)
a Regional warming for the whole Earth if Arctic summer sea ice (ASSI) in June, July and August, mountain glaciers (MG), Greenland Ice Sheet (GIS) and West Antarctic Ice Sheet (WAIS) vanish at a global mean temperature of 1.5 °C above pre-industrial. b Same as in (a) with an additional zoom-in of the Arctic region if only the Arctic summer sea ice vanishes, which might happen until the end of the century. The light blue line indicates the region of removed Arctic summer sea ice extent, where its concentration in CLIMBER-2 is 15% or higher. In all panels, the average additional warming on top of 1.5 °C is shown in absolute degree.

Nico Wunderling, Matteo Willeit, Jonathan F. Donges, Ricarda Winkelmann (2020): Global warming due to loss of large ice masses and Arctic summer sea ice. Nature Communications,
https://www.nature.com/articles/s41467-020-18934-3
Title: Re: The 2020/2021 freezing season
Post by: gerontocrat on October 27, 2020, 06:34:29 PM

The final image makes a 'prediction' for the freeze-over date for the Laptev. The image takes a copy of the blue line from 2012, colors it gold and moves it over exactly horizontally until it extends the most recent 2020 date. A dotted green line is then dropped from the intercept down to the calendar date, intercepting it in late November, almost a full month later than the previous record from 2012.
The assumption is that the Laptev will freeze to maximum almost verically/.

If you look at its neighbour, the Kara, you will see that while this used to be the case in that sea, it no longer is, at least not every year. This tends to show especially in the sea ice area graphs. Sometimes ice growth to maximum is in fits and starts, and sometimes the winter maximum is not 100%.

My speculation is that one year the Laptev is going to go the same way - but in which year?
Title: Re: The 2020/2021 freezing season
Post by: uniquorn on October 27, 2020, 10:40:05 PM
Some of the data included with CryoSat2-Soil Moisture and Ocean Salinity merged sea ice thickness netCDF (oct18-24).

I currently have plot size set to 220 so the map will later crop to 500 pxl width; the scale bar will fit under it if set to 25 with tick format %0f with size 6 font. The map is stereographic at -45º 90º with outer edge 65º.
Will work towards this set up.
Title: Re: The 2020/2021 freezing season
Post by: A-Team on October 28, 2020, 12:15:25 AM
Quote
ocean heat on Siberian shelf has triggered the Siberian shelf methane clathrate release
I interpreted this pre-pre-publication presser slightly differently. The map below is an attempt to locate the location of the six monitoring points. Continental slope is where the continental shelf breaks off to the abyss; it is an area of frequent slumping and landslides like its permafrost counterpart on shore.

Kotolny Island is 1630 km from the pole so the 600km offshore could be scaled from there along with the 10x150 km survey area (which might be crosswise to what's shown). The red area is bounded between 100m to 300m depth according to Mercator Ocean so fits the location of sloping shelf break.

Atlantic Waters move as an eastern boundary current topographically steered by bathymetry to circulate the Arctic Basin at its buoyancy-appropriate depth of about 300m. That fits warming of the survey site by Atlantification according to MO's seawater temperature map.

The Guardian article mentions methane clathrate/hydratse which are CH4 guest molecules trapped in water cages. The depth and temperature here seem too high for its stability zone. [fixed]

Semiletov has previously stressed that upwardly migrating free methane gas (not to be confused with clathrate) may be trapped and accumulating under a lid of underwater permafrost left over from the last ice age when the shelf here was subaerial. There's no stability zone limitations for this. Free methane may be what is being released by warming-induced slumping. The methane craters mentioned are further inland on the shelf proper.

It's true that methane is surprisingly soluble in cold seawater -- not all released goes up to the atmosphere. While certain bacteria can metabolize it to carbon dioxide, those are associated more with a bottom mud layer. One micro-molar methane is implausible as a food source in nutrient poor 0ºC surface waters, especially in view of rapid equilibration with low atmospheric methane concentration. Photosynthetic eukaryotic algae in blooms do not assimilate methane; the sequenced genome of Emhux lacks the genes for the unusual enzymes and cofactors involved.

The reporter here should be applauded for not seeking out 'balancing' quotes from the influential CO2 scientific poobahs that see Semiletov's research as going off-message (off their message) with methane as major and worsening greenhouse gas with potentially catastrophic and unstoppable releases ahead. The dog whistle for that is a 100yr time frame; here the far more appropriate 20yr was taken (though some would do instantaneous).

https://www.usgs.gov/center-news/subsea-permafrost-and-associated-methane-hydrate-us-arctic-ocean-margin

"The 60-member team on the Akademik Keldysh believe they are the first to observationally confirm the methane release is already under way across a wide area of the slope about 600km offshore. At six monitoring points over a slope area 150km in length and 10km wide, they saw clouds of bubbles released from sediment.

At one location on the Laptev Sea slope at a depth of about 300 metres they found methane concentrations of up to 1.6 micro-molar, which is 400 times higher than would be expected if the sea and the atmosphere were in equilibrium.

Igor Semiletov, of the Russian Academy of Sciences, who is the chief scientist onboard, said the discharges were “significantly larger” than anything found before. “The discovery of actively releasing shelf slope hydrates is very important and unknown until now,” he said. “This is a new page. Potentially they can have serious climate consequences, but we need more study before we can confirm that.”

The most likely cause of the instability is an intrusion of warm Atlantic currents into the east Arctic. This “Atlantification” is driven by human-induced climate disruption. The latest discovery potentially marks the third source of methane emissions from the region. Semiletov, who has been studying this area for two decades, has previously reported the gas is being released from the shelf of the Arctic – the biggest of any sea.

For the second year in a row, his team have found crater-like pockmarks in the shallower parts of the Laptev Sea and East Siberian Sea that are discharging bubble jets of methane, which is reaching the sea surface at levels tens to hundreds of times higher than normal.  This is similar to the craters and sinkholes reported from inland Siberian tundra earlier this autumn."
Title: Re: The 2020/2021 freezing season
Post by: uniquorn on October 28, 2020, 12:59:19 AM
CS2SMOS difference between oct22 and oct25 with average uncertainty of those 2 dates.

Not quite ready to let go of a relationship to bathymetry yet so here is the overlay. It reminds me of something noted in august (https://forum.arctic-sea-ice.net/index.php/topic,2417.msg283878.html#msg283878)

added polarview, oct26. Still looks like an active eddy.
Title: Re: The 2020/2021 freezing season
Post by: romett1 on October 28, 2020, 06:23:49 AM
3-day average wind forecast - Kara, Laptev, ESS, Chukchi all restless. Especially Kara Sea.
Title: Re: The 2020/2021 freezing season
Post by: Aluminium on October 28, 2020, 07:33:20 AM
October 23-27.

2019 (https://forum.arctic-sea-ice.net/index.php/topic,2888.msg234605.html#msg234605).
Title: Re: The 2020/2021 freezing season
Post by: uniquorn on October 28, 2020, 11:29:34 AM
iabp buoy204760-764 update, surface temperatures, oct11-28
Title: Re: The 2020/2021 freezing season
Post by: Positive retroaction on October 28, 2020, 11:43:53 AM
hello, I'm starting a little forecast for 7 to 10 days
Thanks again to Uniquorn for the link
If we combine the animation of the extent of the last 7 days, with the salinity and SST at 0 and 30 m, and we look at the forecasts for the next 3 days in air temperature and SST, we deduce

- that kara may be freezing a bit on the south east coast, but not yet in the south west, nor in the central region

- a little frost to come to the west of the new siberian islands, that is to say on the east of laptev

- but more frost seems possible on the eastern half of the ESS, less attacked by the fresh waters of the Chukchi and by the AW
but the rest of the frost seems very difficult, especially on kara of course, but also on the north-east ESS
the winds of these days are likely to bring up the shallow water which was not yet much cooled by the atmosphere and this will increase the SST, especially in kara, with the addition of a southerly flow over Kara
we also note a small hot anomaly which is encrusted slightly in the south west of beaufort, the restant frost of beaufort will be weak and its help on the total extent gain is practically finished, as has been said earlier
That's just my opinion, wait and see :)
all this suggests that if there is a sudden rebound this year, it is not yet for this week
Title: Re: The 2020/2021 freezing season
Post by: BornFromTheVoid on October 28, 2020, 12:07:25 PM
Just looking at the cumulative extent anomaly (vs the 81-10 average) for the Russian Arctic seas, ESS, Laptev and Kara. Already plenty more than any other year's annual total, and likely to see the record breaking anomaly grow over the coming weeks.
Title: Re: The 2020/2021 freezing season
Post by: Freegrass on October 28, 2020, 01:41:03 PM
Latest Five Day Forecast
Wind @ Surface + Total Precipitable Water
Wind + Temp @ 850hPa
Large GiFS!

Nullschool changed their menu and the format. So I have to find a new way to do this...  :-\
Title: Re: The 2020/2021 freezing season
Post by: Phil. on October 28, 2020, 01:55:57 PM
Just looking at the cumulative extent anomaly (vs the 81-10 average) for the Russian Arctic seas, ESS, Laptev and Kara. Already plenty more than any other year's annual total, and likely to see the record breaking anomaly grow over the coming weeks.

Isn't the scale for the anomaly incorrect, shouldn't be thousands of million km^2.
Title: Re: The 2020/2021 freezing season
Post by: Tom_Mazanec on October 28, 2020, 02:02:48 PM
Wouldn’t that be bigger than a continent?
Title: Re: The 2020/2021 freezing season
Post by: sailor on October 28, 2020, 02:12:06 PM
hello, I'm starting a little forecast for 7 to 10 days
Thanks again to Uniquorn for the link
If we combine the animation of the extent of the last 7 days, with the salinity and SST at 0 and 30 m, and we look at the forecasts for the next 3 days in air temperature and SST, we deduce

- that kara may be freezing a bit on the south east coast, but not yet in the south west, nor in the central region

- a little frost to come to the west of the new siberian islands, that is to say on the east of laptev

- but more frost seems possible on the eastern half of the ESS, less attacked by the fresh waters of the Chukchi and by the AW
but the rest of the frost seems very difficult, especially on kara of course, but also on the north-east ESS
the winds of these days are likely to bring up the shallow water which was not yet much cooled by the atmosphere and this will increase the SST, especially in kara, with the addition of a southerly flow over Kara
we also note a small hot anomaly which is encrusted slightly in the south west of beaufort, the restant frost of beaufort will be weak and its help on the total extent gain is practically finished, as has been said earlier
That's just my opinion, wait and see :)
all this suggests that if there is a sudden rebound this year, it is not yet for this week

I would especially mention the "inability" of the ice edge refreeze at West Beaufort to propagate beyond the shelf break of the Canada basin against Chukchi sea. It looks to me there is a continuous flow of Pacific water from Chukchi sea that is precisely descending there, and as long as this water doesn't stop to flow and descend along the break the ice cannot advance.

In the last frames of today's Aluminium animation it seems the ice is finally advancing, but it is difficult to say.
Title: Re: The 2020/2021 freezing season
Post by: Sublime_Rime on October 28, 2020, 02:12:52 PM

The Guardian article does not mention methane clathrate/hydrate which references CH4 guest molecules trapped in water cages. The depth and temperature here seem too high for its stability zone.


Hey A-team, I'm a little confused. Semiletov does mention hydrates in the article via direct quotation: '“The discovery of actively releasing shelf slope hydrates is very important and unknown until now,” he said.'

Also, '"This East Siberian slope methane hydrate system has been perturbed and the process will be ongoing,” said the Swedish scientist Örjan Gustafsson, of Stockholm University, in a satellite call from the vessel.'
Title: Re: The 2020/2021 freezing season
Post by: BornFromTheVoid on October 28, 2020, 02:15:05 PM
Just looking at the cumulative extent anomaly (vs the 81-10 average) for the Russian Arctic seas, ESS, Laptev and Kara. Already plenty more than any other year's annual total, and likely to see the record breaking anomaly grow over the coming weeks.

Isn't the scale for the anomaly incorrect, shouldn't be thousands of million km^2.

It's a cumulative anomaly. So the daily anomalies added up reached 1 million km2 around the start of March, 10 million around mid May, 100 million mid June, and 1,000 million the start of September
Title: Re: The 2020/2021 freezing season
Post by: FishOutofWater on October 28, 2020, 03:58:18 PM
Thanks, A-Team for the details, graphics and clear analysis of what is apparently happening on the Siberian shelf slope. The intrusion of warm Atlantic water and increased convection this fall with the vast area of warm ocean water overturning as the surface cools, increasing its density could be destabilizing parts of the shelf slope. The Storegga slide off the continental slope of Norway is an example of how serious slope instability can be when methane is involved.

The reason I wrote that methane clathrates are involved is the statement you quoted,
“The discovery of actively releasing shelf slope hydrates is very important and unknown until now,”

Methane hydrates are clathrates. Because sea level was much lower in the Pleistocene, permafrost runs deep in the Siberian shelf. The shelf was above sea level 15,000 years before present during the brutally cold Wisconsin period of the ice ages.  Siberian permafrost contains a high percentage of carbon from decayed organic matter that is degraded by bacteria into methane under anoxic conditions. As Atlantification continues slope instability will increase and gas pressure from CO2 and methane will add to the instability. The present lack of sea ice Laptev sea is the surface expression of major changes happening at depth.

The phase diagram below shows that methane hydrates are not stable in shallow sediments under the very shallow parts of the Siberian seas.

(https://upload.wikimedia.org/wikipedia/commons/7/78/Undersea_methane_hydrate_phase_diagram.svg)
Title: Re: The 2020/2021 freezing season
Post by: A-Team on October 28, 2020, 07:26:15 PM
Quote
SubRime: Semiletov indeed says hydrates
Thx, distracted by a trip, fixed it. We might best continue this on the methane forum. By the time it reaches the surface, methane is methane whether it originated primordially, pyrolytically, or from methanogenic archaea with or without passing through clathrate. They might have gravity-cored the slope for hydrate though this was not a drill ship. Otherwise there isn't any good isotopic signature of origin if it's older than 50ky (C14 gone). As BftV notes, Arctic methane is not currently a huge contributor; it might take decades to build up a convincing time series of increase. It would then be too late to do anything about it. It already is, thawing is locked in. With or without this methane, application of the precautionary principle (which would make room for this methane) is long overdue.

The animation below looks at the slow growth of the icepack from the minimum to yesterday, with the spacing of the peripheral edge giving some idea of rate of advance. In conjunction with uniq's direct buoy data, GFS air temperatures, and L4 GHRSST-SSTfnd, seawater and air are not nearly cold enough at this time.

Geronto makes an interesting point wrt erratic growth in the Kara; zlabe's graph does not show any data points and may be overly fit (to logistics curve?) with the Laptev boundaries not specified (is the uptick attributable to sideways growth offshore SZ?).
Title: Re: The 2020/2021 freezing season
Post by: Glen Koehler on October 28, 2020, 08:42:24 PM
Average remaining extent gain (of the last 10 years) would produce a maximum in March 2021 of 12.49 million km2, 1.39 million km2 below the March 2017 record low maximum of 13.88 million km2.

For the 2020-21 maximum NOT to be a record low, remaining extent gain has to be more than 21.0% above the average remaining extent gain of the last 10 years. This is greater than any of at least the last 13 years.
     10-year average gain may not be that useful under this anomalous circumstance.  Those earlier years had already "used up" a lot of open water freezing capacity by this date.  So when 2020-2021 does begin freezing it will have more opportunity for rapid increase.

     But also note that even at the highest remaining gain for the past 13 years (7.61M km2 in 2019-2020), the resulting maximum at 13.49 would still be 0.39M km2 less than the previous record low maximum Extent of 13.88.   To NOT set a new record low Maximum, remaining refreeze must exceed the highest refreeze within the last 13 years by over 5%.

     Even with rapid catch up once freezing begins late, the longer this delay persists, the more difficult it is for refreeze to compensate for so much lost time.  (Duh, another stunningly obvious revelation, but at least I put numbers to it. :D)

      As noted by more learned souls, even if/when Extent more or less catches up to "normal", the thickness and quality of that ice won't be the same.  I hate to use a boxing analogy, (a sport I can no longer watch given what we now know about brain damage), but the ASI is like a boxer who has taken too many punches to the head.  It will get off its corner stool for the next round of melt season in April, but it will be less able to resist further blows if there is another warm or sunny Arctic summer like 2020.  It looks like the 2012 record lows won't last much longer.  Not good. 

     Winter is supposed to be "off-season" for ASIF, when we twiddled our thumbs and waited for the next melt season.  Freeze season is not supposed to be this "interesting."  Now the refreeze race to a depleted maximum is almost as interesting as the annual September minimum derby.
Title: Re: The 2020/2021 freezing season
Post by: Pagophilus on October 29, 2020, 11:02:56 AM
Comments by coelho and Stephan in the area and extent thread highlighted for me that the total extent graph, with its peripheral seas inclusion, is not always the best one to watch when it comes to refreeze.  If one is looking at what is happening in the Arctic Ocean itself, then Gerontocrat's CAS graph might also be tracked.  Below is his latest chart for the CAS (Central Arctic Seas). 
Title: Re: The 2020/2021 freezing season
Post by: uniquorn on October 29, 2020, 12:19:39 PM
CS2SMOS update oct20-26
edit: changed a colour table to avoid confusion. Changed uncertainty to sum.
Title: Re: The 2020/2021 freezing season
Post by: Freegrass on October 29, 2020, 03:10:45 PM
Latest Five Day Forecast
Wind + Temp @ Surface
Large GiF!

It looks like a Laptev cooling wind is coming in...
Title: Re: The 2020/2021 freezing season
Post by: Freegrass on October 29, 2020, 03:18:16 PM
CS2SMOS update oct20-26
edit: changed a colour table to avoid confusion. Changed uncertainty to sum.
I think it would be easier to view if you post the three images separately. Now they're passing by so quickly...
Title: Re: The 2020/2021 freezing season
Post by: uniquorn on October 29, 2020, 05:46:58 PM
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fwww.eumetrain.org%2Fsatmanu%2FCMs%2FClStr%2Fmedia%2Fimages%2Fcscosk01k.gif&hash=b2205a9761e048f6232876784b0df0b0)
http://www.eumetrain.org/satmanu/CMs/ClStr/navmenu.php?page=2.0.0
Quote
Cloud Streets over sea:
In many cases Cloud Streets can be seen during synoptic scale outbreaks of cold, dry air from continents over a neighbouring relatively warm ocean. This flow often occurs behind a Cold front (see Cold Front ). As the cold air leaves the land or ice surface it is modified by vertical transfer of heat and moisture from the underlying water surface. An inversion will be formed the base of which rises with the distance from shore. The formation of the inversion is, in many cases, stimulated by NVA and subsequent sinking motion in the stream upwind of the 500 hPa trough-axis (see image below).
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fwww.eumetrain.org%2Fsatmanu%2FCMs%2FClStr%2Fmedia%2Fimages%2Fcscosk02.gif&hash=4d44c3a530a9e3245c61bc858b5f4ef1)
Quote
The transformation of the air mass eventually leads to the formation of clouds which, under certain circumstances, take the form of Cloud Streets, and develop roughly parallel to the wind direction (see graphic below). Further downwind from the outbreak, the unstable layer becomes deeper, the flow becomes more cyclonic and the streets develop into three-dimensional open cells. Near the upper-trough the convection is enhanced by PVA, resulting in the formation of EC (see Enhanced Cumulus ) and Comma (see Comma ).
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fwww.eumetrain.org%2Fsatmanu%2FCMs%2FClStr%2Fmedia%2Fimages%2Fcscosk03k.gif&hash=448017b172432237596b08f1c05e45ad)
Cloud Streets (http://rammb.cira.colostate.edu/wmovl/VRL/Tutorials/SatManu-eumetsat/SatManu/CMs/ClStr/index.htm)
Quote
Spacing and alignment of Cloud Streets
The distance between adjacent Streets has been observed as approximately three times the height of the inversion or stable layer. Cumulus streets are aligned parallel to, or within a few degrees of, the direction of the wind in the convective layer. Bends in the wind flow are often indicated by bends in the Cloud Streets. A single line of cumuli often extends to more than 100 km downwind; the entire field may extend over 100 km downwind and has been observed to have a width in excess of 500 km. On very high resolution satellite pictures up to 100 nearly parallel lines of cumuli have been observed.

I haven't counted them.  https://go.nasa.gov/34APTKC  oct29
If the quote above is correct then the inversion layer is pretty low.
Title: Re: The 2020/2021 freezing season
Post by: grixm on October 29, 2020, 09:36:19 PM
Almost no parts of the siberian seas that hasn't completely saturated the anomaly color gradient on Nico Sun's charts.  :o
Title: Re: The 2020/2021 freezing season
Post by: Killian on October 29, 2020, 10:33:59 PM
Winter is supposed to be "off-season" for ASIF, when we twiddled our thumbs and waited for the next melt season.  Freeze season is not supposed to be this "interesting."  Now the refreeze race to a depleted maximum is almost as interesting as the annual September minimum derby.

However, completely expected, at least in terms of the trend. I spend most of my "climate" talk time over at RealClimate. One of the observations I made over there in previous years was that the trend for later refreeze and the effects of that in less ice volume and weaker ice: Less time for freezing should lead to thinner ice and less extent, at least in trend, and ice age definitely affects density and resilience.

This was a couple years ago, I believe.

And, of course, the slower the freeze, the more energy input into the ocean/seas, the faster it melts in summer and the greater area the area exposed to insolation, and the later it melts and... round and round we go.

Bifurcations-R-Us.
Title: Re: The 2020/2021 freezing season
Post by: uniquorn on October 29, 2020, 11:18:22 PM
(https://forum.arctic-sea-ice.net/index.php?action=dlattach;topic=3299.0;attach=289598;image)

SST foundation temperature (http://ftp://ftp.star.nesdis.noaa.gov/pub/socd2/coastwatch/sst_blended/sst5km/night/ghrsst_ospo/2020/) (10m) update, oct18-28. click for ani.
Title: Re: The 2020/2021 freezing season
Post by: Glen Koehler on October 30, 2020, 12:36:16 AM
     FWIW - The edited chart below shows how an NSIDC maximum Extent would compare to other years if refreeze from Oct 28 followed the highest rate in most recent 13 years until reaching a maximum in March 2021.  Based on JAXA values posted by gerontocrat: 
https://forum.arctic-sea-ice.net/index.php/topic,2975.msg291409.html#msg291409 (https://forum.arctic-sea-ice.net/index.php/topic,2975.msg291409.html#msg291409)

      To create the hypothetical NSIDC max I increased the extrapolated JAXA max by 0.41 M km2 to account for the difference between JAXA and NSIDC record lows.  (The extrapolated JAXA low would be 13.49).

      Extent value is an incomplete metric to represent the complexity of ASI condition.  Additional dimensions (Area, Volume) and qualitative characteristics (Thickness, salinity, mechanical strength, snow cover, temperature?, density?) are missing from a simple measure of maximum Extent.  In addition to ice measures, it seems that emerging changes in the Arctic Ocean (open water, wave action, water temperature, thermo-halocline stability, Atlantification, currents, storm potential, less ice pack cohesion with greater floe mobility, and more) are almost all on the side of working against ice retention, not promoting it (a possible exception being jet stream changes described by Francis and Wu 2020, https://forum.arctic-sea-ice.net/index.php/topic,2692.msg291501.html#msg291501 (https://forum.arctic-sea-ice.net/index.php/topic,2692.msg291501.html#msg291501))

      Thus, even if the resulting maximum Extent is closer to (or above) the trend line, the 2021 maximum Extent value, whatever it is, will be for ice that on average is almost certainly less resistant to melt than even the most recent historical norm as it heads into the 2021 melt season. 

       It must also be noted that when the long term trend is extracted, the annual maximum Extent has almost no predictive power for the subsequent September minimum.  A dramatically low March maximum at the beginning of the melt season does not tell us what to expect at the end of the melt season. 

      But with the expected effects of late refreeze on ice quality and melt resistance, I wonder if that previous lack of correlation between preceding maximum to the subsequent minimum will continue.  Compounding effects of qualitative decline may emerge from the noise of year-to-year variability to become a separate and identifiable (and measurable, monitored, and reported?) influence.  Just guesswork inspired by hypotheticals.
Title: Re: The 2020/2021 freezing season
Post by: Pagophilus on October 30, 2020, 03:56:19 AM
the annual maximum Extent has almost no predictive power for the subsequent September minimum. 
And of course a recent example of this is the fact that the March maximum this year was the third-highest of the last ten years, yet was succeeded by the recent second-lowest September minimum.  As Stephan was arguing on the extent and area thread, that March maximum extent contains so much information from the peripheral seas, which have their own inherent variability..
Title: Re: The 2020/2021 freezing season
Post by: Aluminium on October 30, 2020, 06:26:19 AM
October 25-29.

2019 (https://forum.arctic-sea-ice.net/index.php/topic,2888.msg234834.html#msg234834).
Title: Re: The 2020/2021 freezing season
Post by: aslan on October 30, 2020, 10:08:24 AM

I haven't counted them.  https://go.nasa.gov/34APTKC  oct29
If the quote above is correct then the inversion layer is pretty low.

Not a lot of time again, sorry, but if models are of any usefulness. From North to South, following more or less the flow : 83.30°N 138.30°E at 03Z the 29th ; 81.00°N 144.00°E at 03Z the 29th ; 77.00°N 145.00°E at 06Z the 29th and same hour 74.30°N 146.00°E
Title: Re: The 2020/2021 freezing season
Post by: aslan on October 30, 2020, 10:40:08 AM
P.S. : About this subject also, CBs -and confirmed by satellites- and snow shower under CB at Kotel'Nyj and Vrangel, wich at this time of year is rare (especially as it is the same kind of weather since 3 days with continous reports of CB...):

http://ogimet.com/cgi-bin/decomet?ind=21432&ano=2020&mes=10&day=30&hora=06&min=00&single=yes

No thunderstorm but it was not far away... (models were also hiting at this possibility).
Title: Re: The 2020/2021 freezing season
Post by: Pagophilus on October 30, 2020, 01:40:03 PM
October 25-29.

2019 (https://forum.arctic-sea-ice.net/index.php/topic,2888.msg234834.html#msg234834).
Thanks as ever, Aluminium.  Looks like the Siberian seas refreeze is beginning to accelerate. 
Title: Re: The 2020/2021 freezing season
Post by: A-Team on October 30, 2020, 02:13:00 PM
Some colder air swung up from the 'lower half' but swung back down, with 80º 140º in mid-Laptev seeing water-cooling temperatures but not enough to create ice given the wind speeds.Ten days to Mov 3rd, needs click to animate. Open water in the Arctic basin still amounts to 35% on 29 Oct 2020.

The double palette histogram shows the spacial and frequency of the temperature distribution SSTfnd statistics. The lower palette is the kelvin water temperature from Panoply of the netCDF; the grayscale value frequencies can be read off the gridded upper palette scale. The pink vertical bar at 64 gray shows the average water temperature to be two degrees celsius above the -1.8ºC freezing point of 32 psu seawater. Next up: animate the histogram over the freeze season to date. The histogram is an im;ortant tool in identifying outliers and thus restricting scale setting in Panoply so as to attain maximal spread across the palette.
Title: Re: The 2020/2021 freezing season
Post by: Freegrass on October 30, 2020, 03:34:04 PM
Latest Five Day Forecast
Wind @ Surface + Total Precipitable Water
Large GiF!
Title: Re: The 2020/2021 freezing season
Post by: SimonF92 on October 30, 2020, 08:44:29 PM
"boots on the ground" buoys are showing its above freezing at the north pole right now

Nullschool strongly contests that  :o
Title: Re: The 2020/2021 freezing season
Post by: A-Team on October 30, 2020, 09:17:12 PM
Boots on the ground ...great update! Do we have a full list of data links to the 5-6 floating in open water on the Siberian side -- and the UTC times of the readings displayed? The blue in the image below shows the latest open water according to AMSR2_AWI for Oct 29th, PM orbits. There are many types of buoys and designs of sensors out there.

The SVP-B   AARI-USIABP Laptev floaters were described earlier: the temperature sensors are in the bottom of the buoy so maybe 30 cm underwater. These buoys measure surfact barometric pressure but not air temperature. The nullschool layer above is described as 'surface' air temperatures for the next day Oct 30th at 18:00 Local Time (please use UTC). Note how rapidly air temperatures change over 3hr increments (see #618 for daily).

If there is a conflict, what it says is that GFS is not assimilating buoy surface air temperatures (2m) so it is basing on distant shore stations or non-reanalyzed weather models as there is no magical satellite layer for this.

It might be more informative to compare the free floating buoy water temperatures with SSTfnd water data which is available as SPO-L4_GHRSST-SSTfnd for Oct 29th. Here the agreement should be good (especially if the latter assimilates the former and only re-grids it!).

The easy way to check is open 'array view' in Panoply and scroll around the temperature numbers over to the lat lon of the buoys. However it is only giving data to integer kelvin values. The location of the buoy (small yellow square) in the Panoply map is again not quite the buoy temperature but here there is an issue of comparing hourly timing to once a day.

We don't actually know how well SSTfnd (10m mixed layer) is supposed to agree with buoys like this which are measuring more like SSTsubskin. Here, the buoy water should sink since colder seawater is denser, bring mixing eddies. The mixing may take time ... weather-driven systems like this are forever approaching equilibrium but never quite get there.

https://tinyurl.com/yxph3zva

The temperature boxes don't show buoy id numbers. Previously we mentioned #204672 (not currently in IADP's table) and #204760-204764 as being located appropriately. The small numeric data files are downloaded if you click on 'Level 1'. The buoy 204764 has been cooling down over the last 14 days and finally gotten below 0ºC though nowhere near -1.8ºC. It is currently at 79.3     126.4 at -0.56ºC.

The graph does seem to have an erratic downward trend so it might be productive to do a least sq fit (ŷ = -0.00593X + 2.68812) and extrapolation (188 hours or 7.8 days to reach -1.8ºC).

https://www.socscistatistics.com/tests/regression/default.aspx
https://iabp.apl.uw.edu/TABLES/ArcticTable.php
Title: Re: The 2020/2021 freezing season
Post by: SimonF92 on October 30, 2020, 11:05:43 PM
Many very good points made A-team, particularly regarding measurement times and retroactively examining data with Level-1. 

At the moment I have been piggybacking off uniquorns efforts with the buoys. Im forcing myself to not use any bespoke applications for parsing the data for learning purposes but hopefully in time im able to produce something more substantive.

There is a wealth of information on "real" (non satellite) data, its just figuring out how best to use it, as im sure you know

Title: Re: The 2020/2021 freezing season
Post by: jens on October 31, 2020, 07:45:17 AM
It looks like peak daily ice gains are happening now. Which means that in terms of extent the advantage of 2020 has peaked for this year. It was 942k a few days ago.
Title: Re: The 2020/2021 freezing season
Post by: A-Team on October 31, 2020, 11:02:34 AM
Quote
peak extent gains are happening now
Based on what? If this a prediction, where is your attached supporting data?

Still record open water for the date by a huge margin, unprecedented delay in Laptev freeze-up, some indication of a Wrangle arm setting up however. The lower basin is largely closed over already, mostly just thickening.

<For the record, Gero made a factual statement about extent data of the past few days. If important or not, saves the ice or not, is another matter. O>
Title: Re: The 2020/2021 freezing season
Post by: gandul on October 31, 2020, 11:25:45 AM
Quote
peak extent gains are happening now
Based on what? If this a prediction, where is your attached supporting data?

Still record open water for the date by a huge margin, unprecedented delay in Laptev freeze-up, but indication of a Wrangle arm setting up?.
Laptev is next, by now it must be well below average in terms of mixed layer enthalpy (my speculation).

<Hints of "allowed narrative" removed. O>
Title: Re: The 2020/2021 freezing season
Post by: A-Team on October 31, 2020, 11:29:36 AM
Our non-stop, never-data climate change minimizer!

How do you know it's an accurate prediction of the future if there is no supporting data (given the future isn't here yet)?

Mixed layer enthalpy speculation .. do you even know where the data for that is located? It takes less than a minute to look at it. It's at an all-time record high for the date for the Siberian side.

The Laptev won't be next: buoy surface temperatures in Laptev are still far from freezing, as are SSTfnd. Five-day temperature at 80º 140º are forecast moderate; ice pack edge is still stalled on AMSR2_AWI. Next: Chukchi-Beaufort northern edge, Wrangel arm towards ESS per OsiSaf trend, historical patterns, GFS weather forecast. Then Laptev. Chukchi by Bering Strait last (Dec/Jan).
Title: Re: The 2020/2021 freezing season
Post by: RikW on October 31, 2020, 12:10:09 PM
Quote
peak extent gains are happening now
Based on what? If this a prediction, where is your attached supporting data?

Still record open water for the date by a huge margin, unprecedented delay in Laptev freeze-up, some indication of a Wrangle arm setting up however. The lower basin is largely closed over already, mostly just thickening.

Well, 500k gain in 2 days is a peak when looking at historic numbers. And gains should be low compared to historic gains to make the difference between now and 2nd lowest year getting around 1M again. The only, although large, but is that the current situation isn’t really comparable to the history we have
Title: Re: The 2020/2021 freezing season
Post by: A-Team on October 31, 2020, 01:49:36 PM
Quote
the current situation isn’t really comparable to the history we have
Right. Where and why did "peak gains" occur, how might that location data be interpreted, what will the gains be tomorrow? Does not daily extent trivia belong on the extent forum?

I see zero interest in endlessly boring copy/pasting off the NSIDC site followed by droning on and on in October about maybe-records next March and Sept 2021. One-day records don't adequately characterize the situation in the Arctic to begin with, plus we don't have the slightest basis yet to predict what will happen.

Maybe we need a separate forum for the actual freezing season. Here we are in the middle of an incredible ongoing open water anomaly event on the Siberian side and we can only muster 5-6 people out of 1783 members to contribute anything. A cargo cult has developed.

There is a tremendous amount to do given three very informative NEW sources of data on top of the usuals. Analysis is just a click or two away but only a few will take those clicks. Many hands make light work: it doesn't get any easier than plotting sea surface temperatures from buoys, it's high school complexity.

Tracking the unprecedented nature of the current freezing season is essential to understanding why it happened, what consequences are likely to follow, and whether it is one-off weather or beginnings of an annual trend. The fall season is peak Arctic Amplification, not a word about it here.

The first, attribution, has seen hand-waving -- but no apportionment -- about early melt, high insolation of resulting open water and winds mixing ice, combined with a Siberian heat wave and overall temperature anomaly. Some aspects of this are newly doable. The second, eg mapping rate of regional growth of ice thickness, is newly feasible from observables. The last needs a global model perspective so best we can do there is find the better journal treatments.
Title: Re: The 2020/2021 freezing season
Post by: romett1 on October 31, 2020, 01:58:04 PM
Ob-Kara region - gains between Oct 30 and Oct 28. However looking at 7-day outlook things are not that rosy.
Title: Re: The 2020/2021 freezing season
Post by: Shared Humanity on October 31, 2020, 02:03:07 PM
Here we are in the middle of an incredible ongoing open water anomaly event on the Siberian side and we can only muster 5-6 people out of 1783 members to contribute anything. A cargo cult has developed.

I come here every day to follow what is going on and will contribute if I have something I think is worth contributing. I suspect that there are others like me. I enjoy your informative posts.
Title: Re: The 2020/2021 freezing season
Post by: Jim Hunt on October 31, 2020, 02:06:49 PM
Holy shit.

The unprecedented ocean heat on the Siberian shelf has triggered the Siberian shelf clathrate "methane bomb".

Climate Feedback responds to the Grauniad article:

Quote
Scientists who reviewed the article explained that it presents some sensational claims and lacks important context. It is not known whether the methane released from the seafloor in this location of the Laptev Sea represents a new or changing release, contrary to the article’s claim, “concern among researchers that a new climate feedback loop may have been triggered that could accelerate the pace of global heating.” It is also not known how much of that methane is reaching the atmosphere, as methane is often dissolved in the seawater and oxidized in these deep settings

etc. etc.

https://climatefeedback.org/evaluation/guardian-article-on-arctic-methane-emissions-lacks-important-context-jonathan-watts/
Title: Re: The 2020/2021 freezing season
Post by: binntho on October 31, 2020, 02:50:55 PM
One thing you learn quite quickly as a programmer is that what you yourself think is easy is pretty much black magic to all non-programmers. In spite of having worked in software development for 30 years, I have absolutely no knowledge or experience in graphics programming and the images that  A-Team and BFTV and Uniqorn and others keep posting here seems like black magic to me. I enjoy it but don't try to convince me that it is easy.
Title: Re: The 2020/2021 freezing season
Post by: binntho on October 31, 2020, 02:55:10 PM
As for the amazing events that we see unfolding in the Arctic at this very moment, what can one do except keep saying "amazing" and other such inanities - we are powerless to stop it, and pretty much fumbling blindly in the dark at the back oft the cage with the blindfolded elephant when it comes to trying to understand what is happening.
Title: Re: The 2020/2021 freezing season
Post by: oren on October 31, 2020, 03:03:04 PM
Quote
the current situation isn’t really comparable to the history we have
Right. Where and why did "peak gains" occur, how might that location data be interpreted, what will the gains be tomorrow? Does not daily extent trivia belong on the extent forum?

I see zero interest in endlessly boring copy/pasting off the NSIDC site followed by droning on and on in October about maybe-records next March and Sept 2021. One-day records don't adequately characterize the situation in the Arctic to begin with, plus we don't have the slightest basis yet to predict what will happen.

Maybe we need a separate forum for the actual freezing season. Here we are in the middle of an incredible ongoing open water anomaly event on the Siberian side and we can only muster 5-6 people out of 1783 members to contribute anything. A cargo cult has developed.

There is a tremendous amount to do given three very informative NEW sources of data on top of the usuals. Analysis is just a click or two away but only a few will take those clicks. Many hands make light work: it doesn't get any easier than plotting sea surface temperatures from buoys, it's high school complexity.

Tracking the unprecedented nature of the current freezing season is essential to understanding why it happened, what consequences are likely to follow, and whether it is one-off weather or beginnings of an annual trend. The fall season is peak Arctic Amplification, not a word about it here.

The first, attribution, has seen hand-waving -- but no apportionment -- about early melt, high insolation of resulting open water and winds mixing ice, combined with a Siberian heat wave and overall temperature anomaly. Some aspects of this are newly doable. The second, eg mapping rate of regional growth of ice thickness, is newly feasible from observables. The last needs a global model perspective so best we can do there is find the better journal treatments.
A-Team, your educational efforts and your analytic contributions are greatly appreciated, and have been served rather generously lately which makes me a very happy reader. However, I must make some moderator comments here:
* Posting "boring" data gathered from various sites may not be glamorous or interesting to some, but it is an important contribution to the forum nonetheless, appreciated by many readers.
* Various extrapolations and discussions of extent data belong in this thread, while the data itself belongs in the data thread. Admittedly current extrapolations to 2021 min (or max) are IMHO meaningless, but they are still allowed and some readers appreciate them.
* Not all users are as analytically or scientifically capable, or have available time, or priorities, or confidence, to contribute as much as others. I know I am quite capable with Excel and some charts but lack both time, ability and inclination to deal with Panoply, netcdf and various other related matters. Tried and failed. So I consume what others produce, I appreciate, I thank, I even press "Like" which might be meaningless to most. But that's all I can do at this present time.
* I think the uptake of these data new sources is slowly growing, and the educational efforts are paying off. More users are joining the heavy analysis bandwagon. However, results take time and patience.
* I encourage users to post their best opinion even if not backed up by hard science or rigorous data (as long as posts are limited in number and length, so as not to drown the thread(s) in noise). Wide participation is an important value and promotes a higher readership in the long term.
Title: Re: The 2020/2021 freezing season
Post by: BornFromTheVoid on October 31, 2020, 03:26:04 PM
Looking at the MASIE data, we've added 596k in the last 2 days. Almost half of this have come from the Russian Arctic seas (ESS +127k, Laptev +73k and Kara +84K).
The CAA, Baffin and Hudson Bay (+103k, +79k and +51k respectively) are the other big gainers.

The north east passage now appears closed off again (extent-wise, obviously not quite an ice bridge).

Title: Re: The 2020/2021 freezing season
Post by: Glen Koehler on October 31, 2020, 04:46:29 PM
<snip> The fall season is peak Arctic Amplification,
     My understanding is that Arctic amplification is primarily due to less ice Extent --> albedo decline --> more sunlight energy absorption by dark open water --> warmer water --> more ice melt --> less ice Extent.  With very little sunlight reaching the Arctic at this time of year, how is it that fall is "peak Arctic amplification"? 
 
     I suppose more open water also creates more moisture in the air and thus a thicker insulating blanket to retain heat emitted by the open water, thus another reinforcing feedback.  But albedo change seems to be the most important forcing change caused by Arctic warming, and that change in net forcing should decline to near nothing in the fall.  So I don't understand how fall could be peak amplification unless "amplification" is a noun that refers to the observable impacts, not as a verb that describes additional forcing contributions.

     Thanks to Oren for "moderating."  I'm one of the 1783 ASIF members with no training in Arctic science or climatology.  I come here to learn and see what's happening in what is arguably the most consequential observable event in human history - the degradation of the Arctic sea ice.  I do work with weather and crop pests, and one of these days I suppose I could learn how to work with netCDF files, but it will never happen.  I have a colleague who does that.  But he doesn't know much about managing insects and diseases that attack crops.  So we each do our part.  We can't each do everything.  It's better if I let him handle the netCDF programming so I can focus on keeping up with the biological developments from my reading of the relevant information from about 1% up to maybe 2%. 

     The world is a complicated place.  It's great that we have access to so much information.  But it is also overwhelming, so we have to pick our spots.  Adding buoy analysis is not the right move for me or for bettering the world.  Scolding me about it is not going to change that. 

     I wish we had 1.7 billion people in the ASIF watching and worrying about the Arctic, whether or not they ever post any data analysis.  ASIF plays an important role in raising awareness, which is a necessary prerequisite for solutions.  I know at least one prominent journalist aware of the ASIF, and I'm sure there are many others.  I hope ASIF remains an open conversation that welcomes all and brings attention to the climate crisis. 
     
     And it IS a crisis even though for political purposes it seems to move too slow to meet that definition.  The faster that train rolls the less we can do about it.  It's already moving, and 30 more years of acceleration is already baked into the cake. It's like Dr. Fauci said about COVID-19, if you think you are here (low on the curve), you are really here (farther along and higher on the curve).  So you have to act accordingly.  Our house is on fire.  We need to support each other in whatever capacity we each have to attack the problem, not each other.
Title: Re: The 2020/2021 freezing season
Post by: El Cid on October 31, 2020, 05:09:56 PM
I don't see anything mysterious in the late refreeze. There were posters in the melting season thread in late August/early September who demonstrated that sea temperatures in the Siberian Seas were way above any previous records, and drew the conclusion that refreeze will also likely be recordbreakingly late there. And so it happened.   
Title: Re: The 2020/2021 freezing season
Post by: bbr2315 on October 31, 2020, 05:13:13 PM
I don't see anything mysterious in the late refreeze. There were posters in the melting season thread in late August/early September who demonstrated that sea temperatures in the Siberian Seas were way above any previous records, and drew the conclusion that refreeze will also likely be recordbreakingly late there. And so it happened.
Moderation in this forum now caters to the lowest common denominator instead of posters like you and A-Team who provide coherent original thought. It is hardly any wonder that repetitive regurgitations of numbers available elsewhere are dominating the discussion and drowning out actual constructive discourse. Very sad, hopefully Neven comes back soon!
<Discussion of moderation belongs to the Forum Decorum thread. O>
Title: Re: The 2020/2021 freezing season
Post by: Pagophilus on October 31, 2020, 05:51:23 PM
Apart from the 'Laptev corner', current Arctic Ocean ice distribution coincides closely with the extent of the Arctic Basin itself.   Data for Oct 31.
https://oden.geo.su.se/map/ 

Title: Re: The 2020/2021 freezing season
Post by: Pagophilus on October 31, 2020, 06:08:44 PM
Arctic ice extent Oct 30, 2020 vs Oct 30 2019, 2016, 2012

http://nsidc.org/arcticseaicenews/sea-ice-comparison-tool/
Title: Re: The 2020/2021 freezing season
Post by: psymmo7 on October 31, 2020, 06:34:30 PM
 Re: The 2020/2021 freezing season
« Reply #634 on: Today at 03:03:04 PM » from Oren about the purpose of this thread.

Thank you for moderating so competently Oren.
I thoroughly agree with your analysis.
Title: Re: The 2020/2021 freezing season
Post by: Pagophilus on October 31, 2020, 06:41:27 PM
We need to support each other in whatever capacity we each have to attack the problem, not each other.

Well said, Glen K.  I completely agree with you, and with Oren.  Thank you for writing your post.

Thank you to all who contribute here, especially to those deep experts who give so much of their time to the cause.
Title: Re: The 2020/2021 freezing season
Post by: A-Team on October 31, 2020, 07:05:49 PM
Here is a possible new daily product -- hourly observational sea surface temperatures from a few Laptev buoys. One looks stuck in ice. A daily graph might be excessive effort but a simple table for the week might be within reach. It is right there as quick text at IABP but sometimes needs a few edits as the data is just the buoy calling Iridium, no one looking at it.

204760  79.08770    74.03980  0.72  305.6  31 Oct

 204761  74.49920  120.31750  -1.52  305.6  31 Oct

 204762  76.09440  125.53490  -0.08  305.6  31 Oct

 204763  76.70450  111.47850  -7.36  305.6  31 Oct

 204764  79.35490  128.56040  -0.24  305.6  31 Oct

Title: Re: The 2020/2021 freezing season
Post by: gandul on October 31, 2020, 07:13:34 PM
Our non-stop, never-data climate change minimizer!
That characterization is not correct, and it is a bit personal, it has a pass of the moderator, but ok, I myself have not been correct in the past.

I attach Zach Labe’s tweet on the Siberian warmth this year. It started in Feb to June then it moved over the Arctic with the July GAAC, and now the Arctic, I think, is returning what was given (and maybe more I speculate).

How important should the hypothesis about Atlantic Warmth reaching the Laptev be against what we have observed, 24h/20days July sun radiation and atmospheric heat all the summer, warmest probably from several millennia, from Siberia and GAAC?
Title: Re: The 2020/2021 freezing season
Post by: Freegrass on October 31, 2020, 08:36:52 PM
Latest Five Day Forecast
Wind + Temp @ Surface
Large GiF!
Title: Re: The 2020/2021 freezing season
Post by: A-Team on October 31, 2020, 08:57:54 PM
The 'Freeform season chatter and light commentary' is a good alternative location for casual posts, as is '2020/21 Freezing Season Predictions' for one-day records and 'Smart and Stupid Questions Feel Free To Ask' for people wanting to become better informed.

It's been quite interesting to read the 'device' forum. No question, desktops are the new buggy whip ...  I have an iPhone, it's read-only, can't do any work, can't display the graphics properly. So who wants to make tiny pictures for a vanishing audience? The cost of a used 21" iMac like the 2009 used above is ~$150 if that (make coffee/sandwich at home, skip starbucks.)

If nobody works, how does any work get done?
 
The main forum has drifted off from citizen-science to chat room and copy/paste. The notion of posting a bald-faced claim without somewhat supporting it with a source, outside link, satellite product, other data or analysis -- who wants to do other people's homework? 

Climate change reminds me of covid19: a lot of immensely uninformed people running around making things worse. The very best communicators are not getting through despite setting up extraordinary resources (eg E Topol).

I post science-lite expository material: open data / freeware / no code / no calculus / no physics / no models but even that now exceeds the interest level.

I've no idea how the unprecedented current anomaly will play out but it is a good stand-in for a tipping point and imminent climate emergency -- and the experts are certainly taking it that way. It is definitely the biggest thing we've seen since the 2007 minimum and GAAC 2012.

The forum event response?  Apathy, tl;dr, bury the message, copy/paste the same old same old like it was 2013. And this is a very interested micro-demographic! It seems wake-up calls don't wake anybody any more ... if so, climate chaos won't end with a bang but a brain-fog whimper.
Title: Re: The 2020/2021 freezing season
Post by: Poldergeist on October 31, 2020, 09:37:33 PM

The forum event response?  Apathy, tl;dr, bury the message, copy/paste the same old same old like it was 2013. And this is a very interested micro-demographic! It seems wake-up calls don't wake anybody any more ...

I understand the feeling of urgency, but I don't understand why it has to be taken out on forum members like me, who are not scientists, but nevertheless like to stay informed. Now I definitely won't post an opinion.
Title: Re: The 2020/2021 freezing season
Post by: Pagophilus on October 31, 2020, 10:47:06 PM

The forum event response?  Apathy, tl;dr, bury the message, copy/paste the same old same old like it was 2013. And this is a very interested micro-demographic! It seems wake-up calls don't wake anybody any more ...

I understand the feeling of urgency, but I don't understand why it has to be taken out on forum members like me, who are not scientists, but nevertheless like to stay informed. Now I definitely won't post an opinion.

I agree with your sentiments and I think I feel as you are feeling, Poldergeist, but I don't think that A-team, for all his deep expertise and contributions, gets to define what this forum is, or what others should think.  A welcoming, engaged community keeps people coming back and learning.

As Glen K wrote, we should attack the problem, not each other.  I, for one, will not be dissuaded from participation.
Title: Re: The 2020/2021 freezing season
Post by: oren on October 31, 2020, 11:58:47 PM
The 'Freeform season chatter and light commentary' is a good alternative location for casual posts, as is '2020/21 Freezing Season Predictions' for one-day records and 'Smart and Stupid Questions Feel Free To Ask' for people wanting to become better informed.
Agree to all the above.

Quote
It's been quite interesting to read the 'device' forum. No question, desktops are the new buggy whip ...  I have an iPhone, it's read-only, can't do any work, can't display the graphics properly. So who wants to make tiny pictures for a vanishing audience? The cost of a used 21" iMac like the 2009 used above is ~$150 if that (make coffee/sandwich at home, skip starbucks.)
Indeed I echo the sentiment, a computer enables much more effective contributions.

The rest I will take as constructive criticism. Yes, each community member can and should strive to do more. Yes, the stuff is doable. No, I don't think there is apathy. And I still encourage all to post, within guidelines. This is especially true for new users who are not sure if their contributions are worth as much as the very quality stuff posted here. My answer is yes, more participation is desirable, and initial posts are always the hardest. At worst, posters could get some flak, but don't give up. If posts don't fit I can always move them elsewhere. The other threads mentioned above are certainly useful and appropriate for various types of posts, and feel free to practice there.
Title: Re: The 2020/2021 freezing season
Post by: oren on November 01, 2020, 12:02:58 AM
Here is a possible new daily product -- hourly observational sea surface temperatures from a few Laptev buoys. One looks stuck in ice. A daily graph might be excessive effort but a simple table for the week might be within reach. It is right there as quick text at IABP but sometimes needs a few edits as the data is just the buoy calling Iridium, no one looking at it.
I will look into it, should be within my skill set, hoping to find the time (crazy week expected at work, but not giving up).
Title: Re: The 2020/2021 freezing season
Post by: VeliAlbertKallio on November 01, 2020, 05:07:48 AM
This freezing season will be interesting also because of relatively unusual atmospheric set up is emerging combines with the unusual starting conditions in Siberian Arctic that is warm, moist and with open seas:

1) The last time that a strong La Niña event developed was in 2010-2011.

2) "One important aspect of La Niña is the effect it could have on the remainder of the Atlantic hurricane season. A La Niña event reduces wind shear, which is the change in winds between the surface and the upper levels of the atmosphere. This allows hurricanes to grow. The hurricane season ends on 30 November and so far there have been 27 named storms. This is more than the 25 predicted by the US National Oceanic and Atmospheric Administration (NOAA) earlier this year."

3) "There are likely to be more storms in Canada and the northern US, often leading to snowy conditions. Southern US states can be hit by drought at the same time."

4) "If a really strong La Niña event were to occur, research suggests that the UK and Northern Europe might experience a very wet winter."

I think the general global set up brings additional flavour how many depressions enter the Arctic if there are many more systems developing in the Atlantic storm season. The waves could also increase scattering of sea ice to seed its growth, but also stir ocean water to bring warm waters up, while also forming pack ice by clearing thinner and weaker sea ice through out this winter.

Worthwhile to glance this article: https://www.bbc.co.uk/news/science-environment-54725970
Title: Re: The 2020/2021 freezing season
Post by: binntho on November 01, 2020, 05:16:54 AM
<snip> The fall season is peak Arctic Amplification,
     My understanding is that Arctic amplification is primarily due to less ice Extent --> albedo decline --> more sunlight energy absorption by dark open water --> warmer water --> more ice melt --> less ice Extent.  With very little sunlight reaching the Arctic at this time of year, how is it that fall is "peak Arctic amplification"? 


This very question was a topic of several posts earlier this month. First a clarification: Arctic amplification is when atmospheric temperatures rise faster in the Arctic than elsewhere. And the missing link in your chain above is the atmosphere. If the energy from peak insolation just stayed in the oceans, to be released elsewhere at a later date, there would not be any Arctic amplification!

It is primarily now, during fall, that the extra energy gathered during peak insolation is released back into the atmosphere. The presence of large areas of open ocean in autmum, oceans that were  baked during peak insolation, and which are now releasing all the pent up energy into the atmsphere, that is indeed the ultimate cause of Arctic amplification.
Title: Re: The 2020/2021 freezing season
Post by: Juan C. García on November 01, 2020, 05:30:31 AM
I've no idea how the unprecedented current anomaly will play out but it is a good stand-in for a tipping point and imminent climate emergency -- and the experts are certainly taking it that way. It is definitely the biggest thing we've seen since the 2007 minimum and GAAC 2012.

The forum event response?  Apathy, tl;dr, bury the message, copy/paste the same old same old like it was 2013. And this is a very interested micro-demographic! It seems wake-up calls don't wake anybody any more ... if so, climate chaos won't end with a bang but a brain-fog whimper.

I am so shocked by what has happened, that I am not doing anything! But in a way, I feel that, even that I should do something on this Forum, the strongest action should be focus on the general public, on people that are not aware of what it’s happening in the Arctic.
Title: Re: The 2020/2021 freezing season
Post by: nanning on November 01, 2020, 06:54:55 AM
I have been lurking and not contributing for a while, and not expert enough to contribute to the cryosphere threads, but I have with much interest followed the past weeks here and especially the posts by A-Team; Glen Koehler; FishOutofWater; aslan; BornFromTheVoid and others as well.
I much appreciate the high quality discussions and science! Many thanks.   Please don't trip over the trolls
Apologies for not 'giving anything back'.
Title: Re: The 2020/2021 freezing season
Post by: romett1 on November 01, 2020, 10:51:01 AM
ESS between Oct 31 and Oct 28 and 7-day outlook.
Title: Re: The 2020/2021 freezing season
Post by: uniquorn on November 01, 2020, 11:32:15 AM
IABP buoys (https://iabp.apl.uw.edu/maps_daily_table.html) sea temperature, oct18-31
data attached as text. (760 is off map in the Kara) 761 data fits with yesterday's coastal refreeze shown on amsr2.
Title: Re: The 2020/2021 freezing season
Post by: BornFromTheVoid on November 01, 2020, 12:31:19 PM
7 day slow animation. I'll get one for the whole month up later too.
Title: Re: The 2020/2021 freezing season
Post by: oren on November 01, 2020, 01:47:58 PM
The Laptev (as defined by "CT map") spent 4 whole months in 2020 with area less than 150k km2 (as calculated by UH AMSR2).
Previous years did this for 3 months (2012*, 2014, 2018, 2019) or less. So a much longer ice free period over a huge region. At some point quantity becomes quality, as the sea has time to warm and mix (details above my pay grade unfortunately).

* 2012 AMSR2 is partial, SSMIS data eyeballed off chart

Looking at NSIDC data gives a similar picture. Note 2020 are has still not risen above all thresholds so final number of days could be a bit higher.
Thanks to Wipneus for the data files.

Click to enlarge images.
Title: Re: The 2020/2021 freezing season
Post by: gandul on November 01, 2020, 02:32:05 PM
Suspiciously correlated with the extreme spring/summer in Siberia and Arctic summer of 2020
Title: Re: The 2020/2021 freezing season
Post by: Paul on November 01, 2020, 02:42:31 PM
I don't see anything mysterious in the late refreeze. There were posters in the melting season thread in late August/early September who demonstrated that sea temperatures in the Siberian Seas were way above any previous records, and drew the conclusion that refreeze will also likely be recordbreakingly late there. And so it happened.

Yep and the fact the Beaufort refreezing fairly quickly seemed quite an obvious prediction. Unfortunately we are seeing what will happen more and more in the future which is the early parts of refreeze will be very slow in regions which have very warm seas from the summer and the reality is, records are being broken in every month apart from September in recent years.

Of course an early Beaufort refreeze and a late Siberian refreeze does not mean the Beaufort will be slow to melt out next year and the Siberian side will melt out quickly again, alot will depend on the winter weather conditions and of course the summer weather patterns. If we get alot of high pressure this winter, the Siberian side could well be thicker than it was at the start of this year where the ice was thin and there was not much fast ice either.
Title: Re: The 2020/2021 freezing season
Post by: bbr2315 on November 01, 2020, 02:44:44 PM
Suspiciously correlated with the extreme spring/summer in Siberia and Arctic summer of 2020
The trade war was already underway during the extreme event of 2019, with COVID accelerating drops in aerosol production, there are probably other contributing factors as well, but I would imagine particulates are particularly important to the evolution of 2019->2020->2021.

Besides the drop in direct anthropogenic aerosols this year, we have also seen a corresponding MAJOR increase in organic aerosol production through the worst-ever fires on record in Siberia and elsewhere.

It is quite interesting that the minute we see our first major, I mean REALLY major, drop in aerosols since WWII (surpassing collapse of USSR), the natural mechanism for creating.... as much or even more (?) atmospheric soot is almost instantaneously activated due to the increase in ambient temperatures and subsequent ignition of many carbon-rich areas of the Arctic and sub-polar regions.

With PIOMAS likely at its worst-ever numbers for the date, this is also clearly playing out in the melt season. While the raw minimum was not as bad as 2012 in September, I would argue the overall state of the Arctic Ocean for this time of year is now a great deal worse than 2012 or any previous year.
Title: Re: The 2020/2021 freezing season
Post by: bbr2315 on November 01, 2020, 02:48:53 PM
I don't see anything mysterious in the late refreeze. There were posters in the melting season thread in late August/early September who demonstrated that sea temperatures in the Siberian Seas were way above any previous records, and drew the conclusion that refreeze will also likely be recordbreakingly late there. And so it happened.

Yep and the fact the Beaufort refreezing fairly quickly seemed quite an obvious prediction. Unfortunately we are seeing what will happen more and more in the future which is the early parts of refreeze will be very slow in regions which have very warm seas from the summer and the reality is, records are being broken in every month apart from September in recent years.

Of course an early Beaufort refreeze and a late Siberian refreeze does not mean the Beaufort will be slow to melt out next year and the Siberian side will melt out quickly again, alot will depend on the winter weather conditions and of course the summer weather patterns. If we get alot of high pressure this winter, the Siberian side could well be thicker than it was at the start of this year where the ice was thin and there was not much fast ice either.
HYCOM shows that the heart of the surviving MYI adjacent to CAA is now drifting MIGHTILY towards and into Beaufort.

(https://www7320.nrlssc.navy.mil/GLBhycomcice1-12/navo/arcticictn_nowcast_anim30d.gif)

I do agree with your second point but it is interesting to note that Beaufort is now closed, and not only is it closed, it is now being smothered in some of the thickest MYI in the Arctic (not that that is saying much, but in this case it is actually 2M+ thick according to HYCOM).

PS: looping through HYCOM, I think a key point in the Laptev's evolution over the past year was actually missed. There was an event in early January 2020 that is plainly visible looping the thickness maps, and during this time, the ice detached from the shoreline. This edge retreated rapidly northward, with minimal refreezing in its wake, stabilizing only around early April.

At that point, the melt season basically began, and the leading edge of the actual ice that had a real chance to form was already wayyyyyyyy north of Siberia in both Laptev and Kara.

This was tied to a major low pressure event in the Kara visible on the ESRL charts for 1/1-1/5 2020. So I would wager that if we see another major event like this in the same location this year, at any point between now and.... February? The same or worse is going to happen in 2021.

Basically, this LP event in the Kara seemed to trigger a massive katabatic wind into the Laptev, which destabilized the melt front at a critical point in its formation. And that ultimately cascaded into the Laptev's current virtually ice-free state on November 1st.
Title: Re: The 2020/2021 freezing season
Post by: BornFromTheVoid on November 01, 2020, 03:27:48 PM
Animation for all of October below

(big file ~11mb, click to play. Higher quality version on twitter: https://twitter.com/Icy_Samuel/status/1322907583611621376)
Title: Re: The 2020/2021 freezing season
Post by: Memshin on November 01, 2020, 06:23:12 PM
As I long time lurker, I often skipped this thread in the past. This year though, I have been impressed by the amount of science and analysis here, by A-Team and several others. While I don't understand everything A-Team posts, I enjoy trying. I do think I have learned a lot recently, especially about the nature of the feedbacks between open water and the atmosphere. So please, keep the science posts coming!
Also, don't mistake inability to contribute here with apathy. Action must come through politics - voting, encouraging others to vote, and pushing officials toward better policies afterwards.
Title: Re: The 2020/2021 freezing season
Post by: RoxTheGeologist on November 01, 2020, 06:46:55 PM

I don't contribute often. Kids and work keep me very busy. That being said, there are very few days when I don't look at the numbers presented here, and read through the analysis.

On the basis of that, I gave an improptu "lunch and learn" presentation at work on the slow refreeze of the Siberian seas and what it might mean. it was based on the fabulous graphics and cutting edge insight that is so often the basis for reading this forum. I gave everybody credit as due, but the usernames did raise a few eyebrows!

I think it heightened awareness, and and a few peoples faces fell.
Title: Re: The 2020/2021 freezing season
Post by: Pagophilus on November 01, 2020, 07:29:43 PM
HYCOM shows that the heart of the surviving MYI adjacent to CAA is now drifting MIGHTILY towards and into Beaufort.

One of the many things I tend to forget is that the drifting MYI entering the Beaufort is drifting almost due south (strictly speaking, SSW).  Looking at the HYCOM image helped me self-correct on that, bbr.  The way most maps are set up, such as the Bremen map, give the visual impression that the ice is somehow mostly drifting to the west.  An optical illusion, I know, but how much does it subtly influence the thinking of some of us non-experts?  Or maybe just me ::)
Title: Re: The 2020/2021 freezing season
Post by: Positive retroaction on November 01, 2020, 08:50:48 PM
thank you Pagophilus, thanks to your message I realized that I could see badly too,
almost to the south, it's true
it is still thick ice that will be less present in the end of spring to stabilize the pack, even if it is true that in recent years there is hardly any ice greater than 2 m anyway.
something intrigued me about the slow BfTv animation for the last 7 days
why this gain, then this sudden loss towards Zevernaya Zemlya, in the extreme NE kara?
the coastal ice has to do all the work and catch up with it.
because of winds?
and rest assured A-Team, I find everything I am learning here very interesting, I have learned more in about 2 months than since I was born about the Arctic, :) I just do not have the level to contribute brilliantly , but it is with enthusiasm that I come to the topic
Title: Re: The 2020/2021 freezing season
Post by: Pagophilus on November 01, 2020, 10:02:27 PM
thank you Pagophilus, thanks to your message I realized that I could see badly too,
almost to the south, it's true
it is still thick ice that will be less present in the end of spring to stabilize the pack, even if it is true that in recent years there is hardly any ice greater than 2 m anyway.
something intrigued me about the slow BfTv animation for the last 7 days
why this gain, then this sudden loss towards Zevernaya Zemlya, in the extreme NE kara?
the coastal ice has to do all the work and catch up with it.
because of winds?
and rest assured A-Team, I find everything I am learning here very interesting, I have learned more in about 2 months than since I was born about the Arctic, :) I just do not have the level to contribute brilliantly , but it is with enthusiasm that I come to the topic

Thank you, Positive retroaction -- I am glad I am not alone in my thought.  Your screen name and the spirit of your post go very well together BTW -- much appreciated in these anxious times (here in the US there is a lot of environmental and other concern with the election so near). 

I think your point about the ice boundary in the NE Kara is valuable -- I can only think it is due to ice motion (perhaps wind-driven) over the past few days.  Others will know more.  I hope it was not melting!  It will be interesting to see how the ice edge there advances in these coming days.  We know that the Laptev got really warm this summer, but so did the Kara...
Title: Re: The 2020/2021 freezing season
Post by: HapHazard on November 01, 2020, 10:04:11 PM
I very highly value all of the data inputs & opinions/translations offered in this subsection of these forums. Where others read the paper every morning (or whatever equivalent these days), I read the Cryosphere subsection of ASIF.

If I didn't work basically 14 hour days, perhaps I'd contribute. However, rest assured that I exert my influence IRL towards combating AGW.

[sorry for being Off Topic]
Title: Re: The 2020/2021 freezing season
Post by: Yuha on November 01, 2020, 10:04:48 PM
Animation for all of October below

BFTV, thanks for these animations. They are really useful in understanding the progress of freeze (or melt during the summer).

A suggestion: Move the last frame, the one shoving the difference between the beginning and the end, as the first frame because the first frame is the one shown when the animation is off.
Title: Re: The 2020/2021 freezing season
Post by: Positive retroaction on November 01, 2020, 11:30:56 PM
Thank you, Positive retroaction -- I am glad I am not alone in my thought.  Your screen name and the spirit of your post go very well together BTW -- much appreciated in these anxious times (here in the US there is a lot of environmental and other concern with the election so near). 

I think your point about the ice boundary in the NE Kara is valuable -- I can only think it is due to ice motion (perhaps wind-driven) over the past few days.  Others will know more.  I hope it was not melting!  It will be interesting to see how the ice edge there advances in these coming days.  We know that the Laptev got really warm this summer, but so did the Kara...

Thank you Pagophilus! I admit I thought about my nickname for a while
And for HapHazard have courage for 14 h work by day, It's amazing, is not easy so have 💪🙂
Yes, I also hope that this new ice did not melt😢
I particularly followed the Kara anomaly, looking the temperatures in vize ilsand
of course without the ice that should already be there, the anomaly continues in an unprecedented and impressive way.
À link (maybe i saw this link on Asif I don't remember.. Sorry)
http://www.pogodaiklimat.ru/monitor.php?id=20069
Just incredible and is a perfect illustration of consequences of more free water on low arhmospheric temperatures, as talked before and without wishing to relaunch the debate on this subject, many other things must be observed
And many others to learn

October is +8,5 °C anomalie, the October Tnn is highter than Tmm October (Tnn-8 degres against - 10, 7degres)

On vize Island, on the center of kara sea,  September and August are the two months the more hot ever recorded
Title: Re: The 2020/2021 freezing season
Post by: oren on November 02, 2020, 02:19:41 AM
Indeed, more on-the-ground very warm October temperature charts from the same source:
* Kotelny Island in the New Siberian Islands (Laptev).
* Golomyanny Island in Severnaya Zemliya (Northern Kara).
* Hayes island (Franz Josef Land).

http://www.pogodaiklimat.ru/monitor.php?id=21432&month=10&year=2020 (http://www.pogodaiklimat.ru/monitor.php?id=21432&month=10&year=2020)
http://www.pogodaiklimat.ru/monitor.php?id=20087&month=10&year=2020 (http://www.pogodaiklimat.ru/monitor.php?id=20087&month=10&year=2020)
http://www.pogodaiklimat.ru/monitor.php?id=20046&month=10&year=2020 (http://www.pogodaiklimat.ru/monitor.php?id=20046&month=10&year=2020)
Title: Re: The 2020/2021 freezing season
Post by: GeoffBeacon on November 02, 2020, 05:13:25 AM
Is this relevant here?

(https://pbs.twimg.com/media/Elye_kWWkAATewu?format=jpg&name=small)


From http://marineheatwaves.org
Title: Re: The 2020/2021 freezing season
Post by: oren on November 02, 2020, 09:29:30 AM
Some Laptev buoy charts based on IAPB (https://iabp.apl.uw.edu/maps_daily_table.html) data.

Click to enlarge.
Title: Re: The 2020/2021 freezing season
Post by: oren on November 02, 2020, 09:30:49 AM
And some buoy charts from the Kara and ESS.

Title: Re: The 2020/2021 freezing season
Post by: Positive retroaction on November 02, 2020, 12:34:18 PM
Thank you Oren and GeoffBeacon for this précisions and complémentaires data
Some more details and stats about vize
It helps to imagine how much heat is stocked in the kara sea
The first graph is the 2020 anomaly , based on the 1981-2010 norms
The second highlights the absolute day-to-day heat records that were broken in 2020 over August and September
In October, and November too, we enter a period where there is more variability, but it remains remarkable and I continue to follow it (today vize is about 13 degrees above the norm)
The annual anomaly is +4,29°C at 1 November
Data sources infoclimat.fr
Title: Re: The 2020/2021 freezing season
Post by: Positive retroaction on November 02, 2020, 12:44:10 PM
And to realize the difference with recent years, here are the rankings of
The hottest minimum temperatures September (shows 2020)
The hottest monthly temperature of August
The hottest monthly temperatures of september
For the last 40 years
French docs again sorry
Data source www.infoclimat.fr
If I found time to do that, I do the same thing for Kotelny Island, Severnaya Zemliya and Hayes island
Title: Re: The 2020/2021 freezing season
Post by: uniquorn on November 02, 2020, 01:05:32 PM
Some Laptev buoy charts based on IAPB (https://iabp.apl.uw.edu/maps_daily_table.html) data.
Click to enlarge.
Thanks Oren
IABP Buoy locations and last ~7day drift paths (static).
Title: Re: The 2020/2021 freezing season
Post by: Positive retroaction on November 02, 2020, 01:45:18 PM
Some Laptev buoy charts based on IAPB (https://iabp.apl.uw.edu/maps_daily_table.html) data.
Click to enlarge.
Thanks Oren
IABP Buoy locations and last ~7day drift paths (static).
With the graphics of Oren, this shows that the 643 is affected by the beginning of frost visible on the animations of BfTv
The 760 is also interesting, it shows that the kara center is still hot and far from freezing, that is also what Mercator oceans says.
Kara and the Isle of Vize have not finished capturing my attention
The vize anomaly is on its way to becoming the longest positive anomaly on record,(before 2016) which is significant in terms of a change in the behavior of the peripherics seas.
Title: Re: The 2020/2021 freezing season
Post by: BornFromTheVoid on November 02, 2020, 02:37:45 PM
Average extent for the Russian seas was just 20% of the average the last 10 years, and just 10% of the 80s average for October.

Title: Re: The 2020/2021 freezing season
Post by: Freegrass on November 02, 2020, 03:32:21 PM
Latest Five Day Forecast
Wind + Temp @ Surface
Large GiF!
Title: Re: The 2020/2021 freezing season
Post by: SimonF92 on November 02, 2020, 05:09:03 PM
And some buoy charts from the Kara and ESS.

Great work with this oren, thanks
Title: Re: The 2020/2021 freezing season
Post by: BornFromTheVoid on November 02, 2020, 06:53:48 PM
Using the rolling 5 day average, the Laptev Sea remains in an unprecedented situation into the beginning of November. The latest date that it's been at least 90% frozen in November 3rd, back in 2018.

Thomas Lavergne has posted another forecast animation that suggests a generally open Laptev sea will continue for at least another week. At the same time, open water starts pushing close to 85N yet again on the Atlantic side.

https://twitter.com/lavergnetho/status/1323274952053788672
Title: Re: The 2020/2021 freezing season
Post by: romett1 on November 02, 2020, 07:56:26 PM
ESS between Oct 29 and Nov 1 and 7-day outlook.
Title: Re: The 2020/2021 freezing season
Post by: uniquorn on November 02, 2020, 10:18:30 PM
It looks like peak daily ice gains are happening now. Which means that in terms of extent the advantage of 2020 has peaked for this year. It was 942k a few days ago.

Recent extent gain does stand out this year. Difficult to quantify any advantage.
edit: y scale was incorrect
Thinking about it more, Gerontocrat and BFTV do a great job of making the data more pleasant to look at, but at the moment we only get one daily data point and one full amsr2/nsidc image per day. The curves and transitions are approximations.
Title: Re: The 2020/2021 freezing season
Post by: gandul on November 02, 2020, 11:32:30 PM
It looks like peak daily ice gains are happening now. Which means that in terms of extent the advantage of 2020 has peaked for this year. It was 942k a few days ago.

Recent extent gain does stand out this year. Difficult to quantify any advantage.
edit: y scale was incorrect
Thinking about it more, Gerontocrat and BFTV do a great job of making the data more pleasant to look at, but at the moment we only get one daily data point and one full amsr2 image per day. The curves and transitions are approximations.
Thank you for your wonderful plots. They basically show an unprecedented very late refreeze finally ensuing.
Title: Re: The 2020/2021 freezing season
Post by: uniquorn on November 02, 2020, 11:54:29 PM
It looks like peak daily ice gains are happening now. Which means that in terms of extent the advantage of 2020 has peaked for this year. It was 942k a few days ago.

Recent extent gain does stand out this year. Difficult to quantify any advantage.
edit: y scale was incorrect
Thinking about it more, Gerontocrat and BFTV do a great job of making the data more pleasant to look at, but at the moment we only get one daily data point and one full amsr2 image per day. The curves and transitions are approximations.
Thank you for your wonderful plots. They basically show an unprecedented very late refreeze finally ensuing.
Thank you for your basic interpretation.
Title: Re: The 2020/2021 freezing season
Post by: nanning on November 03, 2020, 06:07:02 AM
BornFromTheVoid, many thanks for your great graphs.
Information; axes; legend; readability; colourchoices; map inset; context; consequence.. my compliments. (I'm not an expert)
Uniquorn, the way you're going you'll be a master soon imo.
Postive retroaction, thanks, that list of extremes made me stop to think.
Title: Re: The 2020/2021 freezing season
Post by: Aluminium on November 03, 2020, 07:23:40 AM
October 27 - November 2.

2019 (https://forum.arctic-sea-ice.net/index.php/topic,2888.msg235264.html#msg235264).
Title: Re: The 2020/2021 freezing season
Post by: gerontocrat on November 03, 2020, 11:56:16 AM
It looks like peak daily ice gains are happening now. Which means that in terms of extent the advantage of 2020 has peaked for this year. It was 942k a few days ago.

Recent extent gain does stand out this year. Difficult to quantify any advantage.
Thinking about it more, Gerontocrat and BFTV do a great job of making the data more pleasant to look at, but at the moment we only get one daily data point and one full amsr2/nsidc image per day. The curves and transitions are approximations.
I made a different daily change graph to get a better view of this year's late refreeze and to compare it with previous years when extent minimum was very low. I also used 7 day trailing averages which seems to help.

You can see clearly how this year's late refreeze is turning out to be later and stonger than in 2007, 2012 and 2019. You can also see there was no late refreeze in 2016.
Title: Re: The 2020/2021 freezing season
Post by: Pagophilus on November 03, 2020, 01:16:55 PM
A slightly different perspective, using Charctic interactive graph, all years since 1979, with an eye also on the latest Aluminium animation above.
Certainly, the refreeze is now occurring very quickly, but this year's refreeze is still way out there in terms of its remarkable behavior.  And the high rate of refreeze will only continue, IMO, if the Laptev and Kara, which got very warm this summer, are obliging and quickly ice over.  Otherwise, the rate may slacken soon and the 2020 plot may begin to look a bit more like that of 2016.  Interesting days ahead (for the ice and for the world).
https://nsidc.org/arcticseaicenews/charctic-interactive-sea-ice-graph/ 
Title: Re: The 2020/2021 freezing season
Post by: BornFromTheVoid on November 03, 2020, 02:25:40 PM
Latest single day NSIDC extent increase is the largest on record, at +391k, giving a 5 day total of 1.246 million km2 (2nd largest 5 day total, so far...).
No longer the lowest on record now, 44k above 2016 (this varies a little depending on day of the year or date).
Curious to see how long this run of massive increases can continue. Strong southerly winds around Svalbard and Franz Jospeh Land, on and off over the next week, could start sending the ice edge close to 85N once more.
Lots to watch!

Title: Re: The 2020/2021 freezing season
Post by: The Walrus on November 03, 2020, 02:28:56 PM
It looks like peak daily ice gains are happening now. Which means that in terms of extent the advantage of 2020 has peaked for this year. It was 942k a few days ago.

Recent extent gain does stand out this year. Difficult to quantify any advantage.
Thinking about it more, Gerontocrat and BFTV do a great job of making the data more pleasant to look at, but at the moment we only get one daily data point and one full amsr2/nsidc image per day. The curves and transitions are approximations.
I made a different daily change graph to get a better view of this year's late refreeze and to compare it with previous years when extent minimum was very low. I also used 7 day trailing averages which seems to help.

You can see clearly how this year's late refreeze is turning out to be later and stonger than in 2007, 2012 and 2019. You can also see there was no late refreeze in 2016.

I suspect that the stronger refreeze is due mainly to the water surface temperature falling to the freezing range much later in the year, when the air temperature is much colder.  This will facilitate freezing over a much larger area than when the water temperature reaches freezing earlier in the year. 
Title: Re: The 2020/2021 freezing season
Post by: Positive retroaction on November 03, 2020, 02:46:15 PM
Yes and as we see in this graphs of NSIDC,
The strong rebound that is occurring is expected in the case of a year with a very low September minimum , especially with the delay we took in the first month of the frost season.
The years with a very low September minimum are years with a period of strong increase in extent and we already knew this, with the exception of 2016 because it had a good start to the frost season.
Years with a less extreme September minimum, in general, do not have the rebound, except a bad freeze season starting
It makes sense, but maybe it should be remembered
Of course this should be superimposed on the synoptic, but it is an general observation that can be made

What I am saying is trite, but it may be useful to remember that, for people who are hearing from the arctic just then, or who will only hear about this year's good rebound.
The rebound we're seeing is good new, but this is not a sign of good arctic health,  it's just an expected feature of a year with such a low minimum and a poor start to the frost season.
Title: Re: The 2020/2021 freezing season
Post by: SimonF92 on November 03, 2020, 03:11:55 PM
It looks like peak daily ice gains are happening now. Which means that in terms of extent the advantage of 2020 has peaked for this year. It was 942k a few days ago.

Recent extent gain does stand out this year. Difficult to quantify any advantage.
Thinking about it more, Gerontocrat and BFTV do a great job of making the data more pleasant to look at, but at the moment we only get one daily data point and one full amsr2/nsidc image per day. The curves and transitions are approximations.
I made a different daily change graph to get a better view of this year's late refreeze and to compare it with previous years when extent minimum was very low. I also used 7 day trailing averages which seems to help.

You can see clearly how this year's late refreeze is turning out to be later and stonger than in 2007, 2012 and 2019. You can also see there was no late refreeze in 2016.

I suspect that the stronger refreeze is due mainly to the water surface temperature falling to the freezing range much later in the year, when the air temperature is much colder.  This will facilitate freezing over a much larger area than when the water temperature reaches freezing earlier in the year.

Nope, definitely the Mpemba effect  ::)
Title: Re: The 2020/2021 freezing season
Post by: uniquorn on November 03, 2020, 04:17:58 PM
A couple of IABP buoys (https://iabp.apl.uw.edu/maps_daily_table.html) in the right place in the ESS to track sea temperature during refreeze.
SVP-B, UPTEMPO and one undocumented (https://iabp.apl.uw.edu/webdata/).
Quote
UPTEMPO   Upper Temperature of the Polar Oceans
Data attached as txt file.
Over 50hrs at -0.16C suggests there may be a problem with 174639 (https://iabp.apl.uw.edu/webdata/174639.dat)
Title: Re: The 2020/2021 freezing season
Post by: Shared Humanity on November 03, 2020, 04:39:22 PM
Awesome uniquorn! Really cool watching the temps as the buoys move.
Title: Re: The 2020/2021 freezing season
Post by: The Walrus on November 03, 2020, 06:49:52 PM
It looks like peak daily ice gains are happening now. Which means that in terms of extent the advantage of 2020 has peaked for this year. It was 942k a few days ago.

Recent extent gain does stand out this year. Difficult to quantify any advantage.
Thinking about it more, Gerontocrat and BFTV do a great job of making the data more pleasant to look at, but at the moment we only get one daily data point and one full amsr2/nsidc image per day. The curves and transitions are approximations.
I made a different daily change graph to get a better view of this year's late refreeze and to compare it with previous years when extent minimum was very low. I also used 7 day trailing averages which seems to help.

You can see clearly how this year's late refreeze is turning out to be later and stonger than in 2007, 2012 and 2019. You can also see there was no late refreeze in 2016.

I suspect that the stronger refreeze is due mainly to the water surface temperature falling to the freezing range much later in the year, when the air temperature is much colder.  This will facilitate freezing over a much larger area than when the water temperature reaches freezing earlier in the year.

Nope, definitely the Mpemba effect  ::)

If it was the Mpemba effect, would not the water have frozen sooner, rather than later, as your graph depicts?
Title: Re: The 2020/2021 freezing season
Post by: SimonF92 on November 03, 2020, 07:08:45 PM
Slowly working my way through retroactively visualising all the buoys in one go (last 21 days of data)

Some of these sensors are in air and some are not, still need to separate that out.

I also need to generate bounding longitudes for each of the seas to better separate the data as right now it is far too busy- there are 101 currently reporting buoys north of 70N
Title: Re: The 2020/2021 freezing season
Post by: gandul on November 03, 2020, 07:19:04 PM
Quite a spectacle to see landfast coastal ice reach the main pack expansion at hundreds of km of distance.
Title: Re: The 2020/2021 freezing season
Post by: romett1 on November 03, 2020, 07:37:30 PM
ESS, Laptev between Oct 30 and Nov 2 and 7-day outlook. Sea surface temp forecast for Nov 12 also added, seems like it takes some time until Laptev freezes over.
Title: Re: The 2020/2021 freezing season
Post by: gandul on November 03, 2020, 08:17:24 PM
The disruption of the polar circulation, again, is not however going to perpetuate open ocean anymore. ESS really cold, but I believe Laptev too might be closed by mid November. No chance to see a dragon until next year.
Title: Re: The 2020/2021 freezing season
Post by: romett1 on November 03, 2020, 09:02:23 PM
There is lot of warmth on the way from the Atlantic towards Laptev between Nov 11 and Nov 13. Still far away but worth to look at.
Title: Re: The 2020/2021 freezing season
Post by: Pagophilus on November 03, 2020, 10:21:01 PM
Nope, definitely the Mpemba effect  ::)

Well, that lead to me using up 15 mins of my life that I will never get back again.  But it was very interesting and a useful distraction.  So, thanks.  I guess...
Title: Re: The 2020/2021 freezing season
Post by: The Walrus on November 03, 2020, 11:25:04 PM
Nope, definitely the Mpemba effect  ::)

Well, that lead to me using up 15 mins of my life that I will never get back again.  But it was very interesting and a useful distraction.  So, thanks.  I guess...

Yes, I used up about the same amount of time correcting his post.
Title: Re: The 2020/2021 freezing season
Post by: SimonF92 on November 04, 2020, 09:43:56 AM
Sorry both, Mpemba effect is an example of awfully executed pseudoscience- sometimes sarcasm does not carry. Still though, it would be interesting if it was real
Title: Re: The 2020/2021 freezing season
Post by: uniquorn on November 04, 2020, 11:12:11 AM
I made a different daily change graph to get a better view of this year's late refreeze and to compare it with previous years when extent minimum was very low. I also used 7 day trailing averages which seems to help.
Thanks, much clearer.


gmrt bathymetry with amsr2-awi-v103 overlay at 90% with heavy contrast to help view lower concentration ice, oct25-nov3

Siberian coastal ice is shown drifting out to sea. That may fasten up with more northerly winds forecast.

Some discussion upthread about ice movement close to Severnaya Zemlya. It appears that the ice that formed and drifted to the south west did melt or disperse to the point where it became undetectable to amsr2. Too cloudy for viirs brightness temperature to verify, those interested could check if there are any Sentinel images. Coastal Kara ice is spreading from the south east with favourable winds to replace it.

My interest in this presentation is the area north of NSI previously looked at here (https://forum.arctic-sea-ice.net/index.php/topic,3299.msg291254.html#msg291254).
Not much to see but there may be a further weakness over the Lomonosov Ridge. Looking for evidence to identify if there is persistent turbulence causing vertical mixing there.

It's easy to see the more well known turbulent area north east of Chukchi as the warmer Pacific waters sink into the basin.
Recent extent gains have been impressive. There's still a long way to go.
click for movement
Title: Re: The 2020/2021 freezing season
Post by: uniquorn on November 04, 2020, 08:07:39 PM
amsr2-uhh comparison of 2016 and 2020, sep21-nov3.
bad data on 20160924
click for movement (10MB)
Title: Re: The 2020/2021 freezing season
Post by: Pagophilus on November 04, 2020, 09:08:00 PM
NSIDC comparison tool
Nov 3 2020 vs Nov 3 2019, 2016, 2012.
Title: Re: The 2020/2021 freezing season
Post by: Pagophilus on November 04, 2020, 09:11:26 PM
Sorry both, Mpemba effect is an example of awfully executed pseudoscience- sometimes sarcasm does not carry. Still though, it would be interesting if it was real
No worries.  I did get the sarcasm.  I think we are both enjoying the whole thing.   :D
Title: Re: The 2020/2021 freezing season
Post by: El Cid on November 04, 2020, 09:32:09 PM
Actually, we are just about a week behind 2018
Title: Re: The 2020/2021 freezing season
Post by: uniquorn on November 04, 2020, 10:36:32 PM
Actually, we are just about a week behind 2018
Fair point. ASI location this year is very similar but 2018 is in 6th place so doesn't get much attention. (thanks for the table JCG)

1979-2020 noaa concentration on nov2 is here (https://forum.arctic-sea-ice.net/index.php/topic,2906.msg292103.html#msg292103)

Lets look again in a week's time
Title: Re: The 2020/2021 freezing season
Post by: Pavel on November 04, 2020, 11:20:45 PM
Actually, we are just about a week behind 2018
And 2018 was followed by the 2019 melting season. With the one week missing of the freezing season and the lowest volume at the moment it need conditions like the 2017 melt season to avoid new record lows.
Title: Re: The 2020/2021 freezing season
Post by: Aluminium on November 05, 2020, 09:09:29 AM
October 31 - November 4.

2019 (https://forum.arctic-sea-ice.net/index.php/topic,2888.msg235776.html#msg235776).
Title: Re: The 2020/2021 freezing season
Post by: BornFromTheVoid on November 05, 2020, 04:55:19 PM
5 day centred mean extent increases for the last 30 days. Latest date for 2020 is Nov 1st (so covers October 30th to November 3rd), as I reckon the latest daily update for the 4th is an error.

Title: Re: The 2020/2021 freezing season
Post by: Paul on November 05, 2020, 06:02:19 PM
Actually, we are just about a week behind 2018
And 2018 was followed by the 2019 melting season. With the one week missing of the freezing season and the lowest volume at the moment it need conditions like the 2017 melt season to avoid new record lows.

Does not quite work like that though. As I say, a slow refreeze in Laptev does not mean the Laptev will be the first to melt out next year, volume is very low in that region due to a lack of ice hence why the overall volume is low but with the Laptev freezing over quickly and ice early on thickens quickly, I suspect we won't stay lowest on record in terms of volume although if we have a winter like 2016//17 then we may approach record lows again in volume.

The interesting one for me is CAB volume, that is record low and if that continues, that could be a concern for next year.
Title: Re: The 2020/2021 freezing season
Post by: gandul on November 06, 2020, 06:20:45 PM
Question: why is taking so long for the Laptev sea to refreeze this year?
https://twitter.com/zlabe/status/1324737964182700033?s=21
Title: Re: The 2020/2021 freezing season
Post by: Vince O on November 07, 2020, 10:10:03 AM
Hi there all,   well this is my first post though I've been watching things since at least 1990.
  So, though I watch a great deal I don't think I've ever seen the ice start to break apart like JAXA is showing over the last three days. Does this happen ? Is this expected ? It seems a crack is growing though I can't see why. Maybe I'm wrong.
Title: Re: The 2020/2021 freezing season
Post by: aslan on November 07, 2020, 12:42:57 PM
In the end, could you please stop trolling this forum... Yes, record warmth during the Spring leads to an early break up of the sea ice. A lot of heat has been absorbed by Siberian seas. But, no, this is not just one fluke explaining everything! For one part this is taking place in the general trend of the global warming. And the salinity anomaly, the persistence of the heat anomaly up to now, the fact that the southern Chukchi sea is in an even worst shape, the Atlantic front being fixed north of Svalbard and Severnaya Zemlya etc... All of this is not a direct consequence of a large build up of heat in the Siberian seas in the Spring and Summer.  And yes, this will have long lasting consequences. For example, Ostrov Kotel'Nyj mean temperature is currently (as of the 7th included) a f*****g 7.3°C above the previous record for November (-7.7°C as of the 7th vs -15°C for the whole month of November 2012). Even though the temperatures turn back to average, a new record is virtually certain (small detail, but the SYNOP are still coding CBs at this time of year, which is even more extraordinary). Even more extraordinary is the heat record for Cape Tchelouskyne. Freezing degree days are near the record low level of 2016 for the whole Arctic bassin, and as the sea ice is slow to build up, this means that a weak and vulnerable first year ice next Spring is already locked in. This does not mean that there will be a catastrophe next Spring. Only that this increase greatly the probability of such a catastrophe, even with a more average Spring.
Things are not as simple as : some heat wave happening by chance in Spring -> oh a warm Autumn ! -> Yeah but evrything will ease back to average this Winter, we are fine for the next Spring.

P.S. : If Mercator bulletin is of any usefulness, Laptev salinity is around 34 PSU from top to bottom, and it remains to prove that a heat wave can lead to such a salinity anomaly...
Title: Re: The 2020/2021 freezing season
Post by: gerontocrat on November 07, 2020, 03:55:27 PM
The late refreeze in the Laptev is the inevitable result of a multi-year process - the extreme Siberian heat this year has given that process an additional shove on all the seas bordering Siberian Russia.

As yet, that increasing early melt and longer ice free period does not seem to have affected winter sea ice area and extent cover. (Volume is a different story).  My guess is that one year it will, especially as the attached open water graphs show how this Atlantification process has spread from the Barents to the Laptev and has reduced winter sea ice cover in the Barents and Kara.
___________________________________________________________
ps:-I have added the ESS graph - which I reckon is being attacked by Atlantification and Pacification.

Title: Re: The 2020/2021 freezing season
Post by: gandul on November 07, 2020, 04:49:55 PM
In the end, could you please stop trolling this forum... 
I don’t know who are you talking to but in my experience, “troll” is often the expletive used by those who want an all-agree uniform discussion.

Northern Laptev salinity: there are documents back in the 90’s describing the surface salinity level shown in Mercator. Nothing new.

ftp://ftp.nodc.noaa.gov/nodc/archive/arc0001/9800040/1.1/data/0-data/atlas/html/intro/intro_lp.htm
Title: Re: The 2020/2021 freezing season
Post by: gandul on November 07, 2020, 05:28:09 PM
The late refreeze in the Laptev is the inevitable result of a multi-year process - the extreme Siberian heat this year has given that process an additional shove on all the seas bordering Siberian Russia.

As yet, that increasing early melt and longer ice free period does not seem to have affected winter sea ice area and extent cover. (Volume is a different story).  My guess is that one year it will, especially as the attached open water graphs show how this Atlantification process has spread from the Barents to the Laptev and has reduced winter sea ice cover in the Barents and Kara.
___________________________________________________________
ps:-I have added the ESS graph - which I reckon is being attacked by Atlantification and Pacification.

Multiyear? So what happened in 2016 and in 2017. The Atlantification of the Laptev took a break??

I remember well both springs. 2016 was warm everywhere, but the Laptev coast melting suffered a delay due to the fact that a lot of ice drift streamlines had been converging during winter/spring toward ESS and Laptev, and the transpolar had been disrupted that winter not inducing as much peel-off on the Laptev coasts, leading to a high Laptev ice volume.

In 2017 spring simply started a few weeks late especially in Eurasia due to the high snow cover volume and late thaw. The whole summer was relatively cold.

I bet the relentless reduction of ice in Laptev can be explained by atmospheric climate change without having to resort to the obscure hypotheses of Atlantic Water effects. Global warming effects on oceans is slow and often counterintuitive. Reserves for heat are enormous given the dimensions and the heat capacity. Characteristic times of change are of the order of hundred years.

Granted, it is more entertaining and novel-esque to focus the attention on impossible to verify heat sources and impossible to measure methane time-bombs. To each their own.
Title: Re: The 2020/2021 freezing season
Post by: oren on November 07, 2020, 05:59:52 PM
Hi there all,   well this is my first post though I've been watching things since at least 1990.
  So, though I watch a great deal I don't think I've ever seen the ice start to break apart like JAXA is showing over the last three days. Does this happen ? Is this expected ? It seems a crack is growing though I can't see why. Maybe I'm wrong.
Welcome, Vince O.
Title: Re: The 2020/2021 freezing season
Post by: Jim Hunt on November 07, 2020, 06:21:38 PM
Hi there all,

Hi Vince,

You may wish to check out the SMOS "thin sea ice thickness" product:

https://seaice.uni-bremen.de/databrowser/#p=smos

Does this show the "cracking" you refer to?
Title: Re: The 2020/2021 freezing season
Post by: uniquorn on November 07, 2020, 09:28:45 PM
The interesting one for me is CAB volume, that is record low and if that continues, that could be a concern for next year.
This may not affect volume too much but the CAB is still very sensitive to prevailing winds along the Atlantic front. Extent drifted further into uncharted territory yesterday and looks like it may drop a little more today.

amsr2 awi v103, nov6-7
wipneus CAB extent, nov6
Title: Re: The 2020/2021 freezing season
Post by: aslan on November 07, 2020, 09:56:09 PM

Multiyear? So what happened in 2016 and in 2017. The Atlantification of the Laptev took a break??

I remember well both springs. 2016 was warm everywhere, but the Laptev coast melting suffered a delay due to the fact that a lot of ice drift streamlines had been converging during winter/spring toward ESS and Laptev, and the transpolar had been disrupted that winter not inducing as much peel-off on the Laptev coasts, leading to a high Laptev ice volume.

In 2017 spring simply started a few weeks late especially in Eurasia due to the high snow cover volume and late thaw. The whole summer was relatively cold.

I bet the relentless reduction of ice in Laptev can be explained by atmospheric climate change without having to resort to the obscure hypotheses of Atlantic Water effects. Global warming effects on oceans is slow and often counterintuitive. Reserves for heat are enormous given the dimensions and the heat capacity. Characteristic times of change are of the order of hundred years.

Granted, it is more entertaining and novel-esque to focus the attention on impossible to verify heat sources and impossible to measure methane time-bombs. To each their own.

Troll is for someone flooding the forum with the same argument over and over, ignoring the contributions of the others members.
Multi year does NOT mean it is monotonically worst year after year, but that it is a trend. The year 2012 was worst than the year 2007, the year 2016 was worst than the year 2012, and the year 2020 is worst than the year 2016. Perhaps 2021 will be even worst, perhaps not, who know. But only for you does a trend mean each year being monotonically and significantly worst than the preceding year.
And again, at some point which is now probably really not that far away, the trend will overwhelmed the Arctic and tip the Kara sea to a perenially open sea (and the Laptev and Chuckchi are next in line).
In your document, salinity is described as being in the range 22 to 32 PSU at surface, reaching 33 to 34.5 PSU at one hundred meters (100 meters). Just read...

Quote
The temperature and salinity fields show large gradients between the mixing zones of river and sea water and the uniform thermohaline structure of the northern Laptev Sea. In the wintertime, due to a sharp decrease in runoff, increase in ice cover, and decrease in convection processes, the thermohaline structure is relatively homogenous. The water temperature varies from -1.4° in the eastern sea, up to -0.8° in the northwestern sea. The water salinity in the southwestern sea has values of 22-24 0/00, smoothly increasing northward and to the northwest up to 32-34 0/00. Figure 7 shows the vertical temperature and salinity profiles for the western, southeastern, and northern regions of the Laptev Sea in the summertime. In summer the southwestern upper 15 meter layer is warmed to a temperature of 5 ° - 7° . In the southeastern part, temperatures increase to 1° and remain about -1° in the northern areas. In winter a vertical temperature and salinity distribution in the shallow area is quite uniform, the salinity weakly increasing with depth and the temperature being within -0.5° - 1.9° C, depending on the region. In the deep northern Laptev Sea a temperature maximum is observed at a level of 100-400 m, the salinity dramatically increases from the surface to a 100 m level from 29 to 33-34.5 0/00 and changes little at greater depths.

This year, we are speaking of salinity significantly above 34 PSU, nearing 34.5 PSU if we trust MERCATOR, at surface, in winter, in Laptev. Not at a depth of 100 or 800 meters, at surface.
And you don't answer the question, why then the ice boundary is set northward of 81 - 82°N or something like this, from Svalbard to Severnaïa Zemlaïa, if this is just some direct consequence of huge inertia from the Spring heat wave over Siberia (and by the way why there is still probably some bottom melt ongoing there, to be exhaustive).
Title: Re: The 2020/2021 freezing season
Post by: aslan on November 07, 2020, 10:36:17 PM
And weather forecast is not encouraging. Likely not as worst as mid November 2016 (second picture), but still quite bad with a strong low and a massive heat advection.
Title: Re: The 2020/2021 freezing season
Post by: oren on November 07, 2020, 11:04:12 PM
Aslan, while I support your science position here, plrase avoid troll name calling. I will monitor what feels like a pet theory situation, but please leave it to me. Otherwise flames will go higher when they should go lower.
Title: Re: The 2020/2021 freezing season
Post by: Vince O on November 08, 2020, 03:20:35 AM
Hi Jim, thanx but no Todays JAXA / AMSR2 graphic again shows a bigger area of disappearing ice which I've never seen before in the near five years I've been watching JAXA. Here's the new image. Maybe it's an anomaly but for four days in a row now and growing. . . ?  I looked on Polarview to check and there is thinning in the same area but the picture is from a few days back when it wasn't so prominent.
Title: Re: The 2020/2021 freezing season
Post by: Jim Hunt on November 08, 2020, 11:10:40 AM
Todays JAXA / AMSR2 graphic again shows a bigger area of disappearing ice which I've never seen before in the near five years I've been watching JAXA.

So that's the Kara Sea ice edge? I still can't work out what you're referring to. Can you annotate an image to clarify?
Title: Re: The 2020/2021 freezing season
Post by: Vince O on November 08, 2020, 11:23:33 AM
Here, I thought I did. Like I said, maybe it's a JAXA software anomaly but its getting bigger
Title: Re: The 2020/2021 freezing season
Post by: gerontocrat on November 08, 2020, 01:05:15 PM
Looks like a satellite problem for Univ Bremen
Title: Re: The 2020/2021 freezing season
Post by: Jim Hunt on November 08, 2020, 05:02:51 PM
Here, I thought I did.

You may know what you're looking at, but I still don't!

What I had in mind was something like this:

Title: Re: The 2020/2021 freezing season
Post by: oren on November 08, 2020, 05:06:22 PM
I think Vince O means this, in the image he uploaded.
However I think it's an artifact that can be ignored, as it does not seem to appear in the other products posted here.

Title: Re: The 2020/2021 freezing season
Post by: Pagophilus on November 08, 2020, 05:07:28 PM
I bet the relentless reduction of ice in Laptev can be explained by atmospheric climate change without having to resort to the obscure hypotheses of Atlantic Water effects. Global warming effects on oceans is slow and often counterintuitive. Reserves for heat are enormous given the dimensions and the heat capacity. Characteristic times of change are of the order of hundred years.

The atmosphere and oceans form an integrated system, so I think arguing a solely atmosphere-based effect hypothesis for any changes in the Arctic (beyond short-term effects on the order of a week or a month) is perilous. Most of the extra heat that is trapped by our planet due to climate change is going into the oceans, and you are correct of course: that quantity of heat is enormous.

The effects of the this heating of the oceans may only show up gradually, but does it then follow that these effects are somehow not now showing up in the Laptev now, following at least a century of oceanic warming?  A warming effect can be gradual (as you state it is in the oceans) and it can then manifest itself rather dramatically through the medium of ice extent, since this phase transition is so dramatic to us. 

I am not expert enough to argue whether or not Atlantification of the Laptev is taking place. I am not denying that the extreme Siberian heat this summer did not have a profound effect on the adjacent seas, and particularly the Laptev -- that seems evident to me.  But I agree with aslan that taking a more holistic approach, and looking at trends over several years, including both atmospheric and ocean effects, is the more logical way to approach this.
Title: Re: The 2020/2021 freezing season
Post by: Glen Koehler on November 08, 2020, 08:06:46 PM
    And now we can add warm Siberian river drainage into the Arctic Ocean as another factor (article posted upthread).  Given the record breaking high Siberian temperatures over land in summer 2020, the river water draining those areas must have been especially warm.
Title: Re: The 2020/2021 freezing season
Post by: oren on November 08, 2020, 10:08:42 PM
I did try to find temperature data of the Lena in real time, and compare to other years, but found the task beyond my abilities although I am quite sure the data exists. Maybe some Russian speaker here can manage to find this data.

There was a thread dealing with river discharge and other related issues.
https://forum.arctic-sea-ice.net/index.php/topic,3034.0.html (https://forum.arctic-sea-ice.net/index.php/topic,3034.0.html)
Title: Re: The 2020/2021 freezing season
Post by: Cook on November 08, 2020, 10:22:38 PM
It is complicated.

https://hess.copernicus.org/preprints/hess-2016-254/hess-2016-254.pdf

Enjoy...
Title: Re: The 2020/2021 freezing season
Post by: Pavel on November 09, 2020, 09:15:30 AM
I've found this russian site
https://travel.org.ua/water/ijul/reka-lena-(vozle-yakutska)-temperatura-vody
For examle, this is a chart of July 2020 compared with July 2019 water temperature on the Lena rive near Yakutsk
Title: Re: The 2020/2021 freezing season
Post by: jdallen on November 09, 2020, 10:43:16 AM
    And now we can add warm Siberian river drainage into the Arctic Ocean as another factor (article posted upthread).  Given the record breaking high Siberian temperatures over land in summer 2020, the river water draining those areas must have been especially warm.
Yes, but in context, not a major player in the total energy equation currently playing out.  The impact of circum-arctic drainage is much more important early in the melt season.  Once albedo drops and insolation rises, the effect of a few thousand km3 of warmer water becomes less significant.  At this point in the year, it is of far less import than continuing inflow from Atlantic currents and atmospheric circulation where the remnants of tropical storms drag huge influxes of moisture into the Arctic.
Title: Re: The 2020/2021 freezing season
Post by: jdallen on November 09, 2020, 11:00:31 AM
I'll try to put my thoughts together in something more coherent, but let me put it this way, at the most elemental level:

It's all about Enthalpy.

Increased capture, reduced outgoing radiation mean the total heat present in the Arctic ocean has greatly increased.  (restricted by increased water vapor content in the atmosphere, along with additional CH4 and the increases in CO2... remember just how powerful a green house case H20 is...)

Ice can't form until sufficient heat has left the ocean surface to permit phase change to take place.  We already know that the water column has been disrupted, and that Atlantic water (and heat carried with it) is much closer to the surface and more accessible than the past.

Simply put, with the current energy balance, the Arctic can't dump the heat fast enough.

Even without the present throttling effects of weather (higher atmospheric temperatures and increased humidity, among other factors), the typical export of heat out of the atmosphere is not going to be able to dissipate the additional heat captured during the melt season. Heat simply won't get radiated out of the top of the atmosphere fast enough.

So, the bigger pile means there is that much more heat present which must get moved *somewhere* before the physics of phase change will permit the ice to form, over very large areas of the Arctic.

Unfortunately I don't have quantitative values to present here on this, but I think the qualitative argument should still be compelling.  As a rough estimate, the Arctic picked up something like 30% more energy this year during the melt season, *before* we factor in intrusion of Atlantic heat.

It can't get dumped fast enough.
Title: Re: The 2020/2021 freezing season
Post by: grixm on November 09, 2020, 01:32:14 PM
We might see some extent stalling, even losses, in around 5+ days, as the Kara sea, which has a lot of thin ice and is one of the main growth frontiers now that the laptev is all but closed, will likely experience a surge of warm air from the Atlantic. Even a large portion of the CAB is forecast to see above-freezing temps for a spell.
Click to play.
Title: Re: The 2020/2021 freezing season
Post by: oren on November 09, 2020, 02:27:14 PM
jdallen, well written but I believe at the qualitative level (the only level I am able to discuss) there is also salinity. Those seas (especially Laptev) that melted first and had lots of time under an open water regime and with lots of wind this year in the Arctic, have had time to mix the fresh surface layer that results from ice melt and river discharge, therefore making refreeze even harder and more delayed than if just enthalpy was involved.
Title: Re: The 2020/2021 freezing season
Post by: gandul on November 09, 2020, 03:39:16 PM
Yes, well, salty water that eventually finds its way down, along with the excess salt of the freezing surface, to beneath the mixed layer by something called gravity leaving renovated with river runoff the fresher (and freezing) water at the top.
That’s why, according to textbooks, and until this date (the opposite not been seen empirically, ever) there’s an halocline in the Arctic occupying ample vertical space in the band 50-200 m between the mixed layer and the Atlantic water.

And this halocline is why the Arctic has been protected from the Atlantic Water mass heat at >200 m for hundreds or thousands of years (textbook stuff).

https://doi.org/10.1016/0198-0149(81)90115-1

Note that, at that time the authors were worried with river water diversions. Funny how things change.


Title: Re: The 2020/2021 freezing season
Post by: oren on November 09, 2020, 04:08:42 PM
Gandul you are running with a pet theory and it is disruptive.
The halocline can be disrupted, as happened in the Barents. Not been seen empirically ever? I think you are wrong. I am not at the level to do battle and not enough time on my hands but I do not wish this to be posted and reposted without sufficient scientific backing. If you wish, start a new thread about Atlantification yes or no, or something like that, and there it can be discussed to your heart's content and in the appropriate level to refute and/or understand stuff without disrupting the main thread.
Otherwise I will remove and edit as I see fit.
Title: Re: The 2020/2021 freezing season
Post by: sailor on November 09, 2020, 04:53:04 PM
Guys could we please end this off-topic for this thread?
Oren, Gandul, JD, Aslan, etc. please let's keep the focus on the 2020 freezing season.
Gandul, you couldn't shup up could you? Valuable contrubutors are leaveing the thread, again.
Title: Re: The 2020/2021 freezing season
Post by: uniquorn on November 09, 2020, 05:42:10 PM
I think Vince O means this, in the image he uploaded.
However I think it's an artifact that can be ignored, as it does not seem to appear in the other products posted here.
amsr2 shows lower concentration ice in the same area yesterday with some persistence over the last 3 days further east. It looks like the wet ice we see during the melting season but it has been too cold for that. Perhaps some fog related event from opening leads.
Brightness temperature bands are interesting to explore during winter night.
3 are shown below (click). The link provides 4 of them already set up.
https://go.nasa.gov/3kimitP
Title: Re: The 2020/2021 freezing season
Post by: BornFromTheVoid on November 09, 2020, 06:36:38 PM
The Atlantic edge pushing northward quite quickly so far this month

Title: Re: The 2020/2021 freezing season
Post by: uniquorn on November 09, 2020, 08:31:51 PM
Surface waters properties in the Laptev and the East-Siberian Seas
in summer 2018 from in situ and satellite data
A Tarasenko et al     31 July 2019
https://os.copernicus.org/preprints/os-2019-60/os-2019-60.pdf   free full text
Title: Re: The 2020/2021 freezing season
Post by: Niall Dollard on November 10, 2020, 12:17:39 AM
I think Vince O means this, in the image he uploaded.
However I think it's an artifact that can be ignored, as it does not seem to appear in the other products posted here.
amsr2 shows lower concentration ice in the same area yesterday with some persistence over the last 3 days further east. It looks like the wet ice we see during the melting season but it has been too cold for that.

I referred to this weak area in this post (https://forum.arctic-sea-ice.net/index.php/topic,3299.msg290206.html#msg290206) on Oct 17th. Back then PSL indicated it was only about 20cm thick.

Since then it has only slightly thickened by about 10cm. 
Title: Re: The 2020/2021 freezing season
Post by: jdallen on November 10, 2020, 06:58:31 AM
Guys could we please end this off-topic for this thread?
Oren, Gandul, JD, Aslan, etc. please let's keep the focus on the 2020 freezing season.
Gandul, you couldn't shup up could you? Valuable contrubutors are leaveing the thread, again.
With respect, my content *is* in relation and relevant to the current refreeze.

To Oren - salinity differences are going to result in a freezing temperature increase of only about 0.5c at most, and that will only be fairly close to the continental margins where ice is already forming.  The loss required for a phase change to take place remains the same.  Similarly, the increased distribution of heat to higher levels in the water column remains an obstacle.

Heat, both that being imported from further south - as very nicely illustrated by some of the weather posts I've seen - and what was picked up this summer are the key obstacles the freeze needs to overcome.

As an additional example underscoring my point, here's a frame grab 3 days out showing a major intrusion of moisture into the Atlantic side of the basin.  The effect of this is two fold; 1st, it seriously throttles out-going heat that needs to leave the atmosphere.  That's actually the biggest direct effect, in my estimation.  2nd, the phase change of that moisture from vapor to liquid to ice will replace some non-trivial fraction of the heat that would otherwise come out of the ocean, slowing the freeze.  The more of these plumes we see blowing into the basin, the bigger the challenge there will be to getting thicker ice.


https://climatereanalyzer.org/wx_frames/gfs/arc-lea/pwtr/2020-11-09-18z/09.png
Title: Re: The 2020/2021 freezing season
Post by: aslan on November 10, 2020, 07:10:53 AM
Guys could we please end this off-topic for this thread?
Oren, Gandul, JD, Aslan, etc. please let's keep the focus on the 2020 freezing season.
Gandul, you couldn't shup up could you? Valuable contrubutors are leaveing the thread, again.

Yes, even more as there is things to discuss. The weather is going to be extremely moist, mild and windy in the coming days. As grixm said, extent stall or even decline is likely. It is even more interessting because, by chance, the same happened at about this time of year in 2016. We will see the difference between the two years. In 2016, Arctic as a whole was warmer, but in 2020 the push is going to be stronger with a deeper low and a stronger heat advection. And even though extent does not stall, massive retreat of the Atlantic front from Svalbard to Svernaïa Zemlaïa is highly likely. Which is in the continuity with preceding posts, by the way, as the Atlantic front is already quite vulnerable... As uniquorn said, brightness temperature are usefull in winter, and the picture is not reassuring :

https://worldview.earthdata.nasa.gov/?v=-772046.8209589699,-475019.84206839127,2043200.5753692852,865155.2205587052&p=arctic&l=Reference_Features,AMSRU2_Sea_Ice_Brightness_Temp_89V(hidden),AMSRU2_Sea_Ice_Brightness_Temp_89H,Reference_Labels(hidden),Coastlines,VIIRS_NOAA20_CorrectedReflectance_TrueColor(hidden),VIIRS_SNPP_CorrectedReflectance_TrueColor(hidden),MODIS_Aqua_CorrectedReflectance_TrueColor(hidden),MODIS_Terra_CorrectedReflectance_TrueColor

It will be to seen also what happen to the Laptev hole, and to follow the heat records for the Russian islands...


P.S. : Sea state (colored arrows), winds at 10m (20kt threshold), sea level pressure, and isotherm -5°C at 850 hPa, for one weather model at 12Z Friday, from 00Z his morning.
Title: Re: The 2020/2021 freezing season
Post by: El Cid on November 10, 2020, 07:27:42 AM
The very late refreeze was no surprise after the extreme SSTs observed during Aug/Sep. Even the current fast refreeze was not a big surprise as it was bound to happen because air is much colder now than at previous (earlier) refreeze dates.

However, I found it most fascinating that (at least the Siberian side) freezes as if it was a lake: from the shores towards the center. Previously, the Arctic used to (mostly) freeze from the center towards the shores.
Some posters previously speculated that this will be more and more common in the future...it seems so. Amazing to see this happen
Title: Re: The 2020/2021 freezing season
Post by: bbr2315 on November 10, 2020, 12:56:10 PM
The very late refreeze was no surprise after the extreme SSTs observed during Aug/Sep. Even the current fast refreeze was not a big surprise as it was bound to happen because air is much colder now than at previous (earlier) refreeze dates.

However, I found it most fascinating that (at least the Siberian side) freezes as if it was a lake: from the shores towards the center. Previously, the Arctic used to (mostly) freeze from the center towards the shores.
Some posters previously speculated that this will be more and more common in the future...it seems so. Amazing to see this happen
Perhaps this "dis-ordered" refreeze also explains why the ice was so quick to retreat from the Laptev shores this past January (and also why it never really refroze in any meaningful way thereafter).

Central ice expanding to shoreline -> thick ice, growing in thickness, to the shoreline.

Central ice stagnant and shore ice expanding to it -> thin ice, expanding in area but not really volume, to the CAB / when the winds blow from the land, this thin ice then retreats TOWARDS the CAB as the ice between it and CAB breaks apart / crumples.
Title: Re: The 2020/2021 freezing season
Post by: aslan on November 10, 2020, 02:34:02 PM
I think Vince O means this, in the image he uploaded.
However I think it's an artifact that can be ignored, as it does not seem to appear in the other products posted here.
amsr2 shows lower concentration ice in the same area yesterday with some persistence over the last 3 days further east. It looks like the wet ice we see during the melting season but it has been too cold for that. Perhaps some fog related event from opening leads.
Brightness temperature bands are interesting to explore during winter night.
3 are shown below (click). The link provides 4 of them already set up.
https://go.nasa.gov/3kimitP

It would be better to see also the 18GHZ and 37GHz but I don't know if there is an easy way to vizualise this data. To my knowledge, ice thickness is retrieved from ratio of polarisation for the band 37 GHz and 19 Ghz, perhaps others channels in the same vicinity (6, 7, 23 GHz). This is, while sea ice concentration is retrieved from the 89 Ghz band. I agree this is still worth a closer look, even though it is not really open ocean. I am wondering what the AMSR2 is seeing in the 37 GHz chanel... This said, ice thickness can't be calculated from brightness temperatures if the value is less than ~0.2m. Usually, this lead the algorithm to calculate a "melt fraction", which is not always very pertinent. It is thus likely that either way, the ice thickness is probably quite low, pushing the algorithm to the edge. With possible other effects like the open leads, the ocean being not so cold, etc... This can be an explanation.
Title: Re: The 2020/2021 freezing season
Post by: BornFromTheVoid on November 10, 2020, 06:25:18 PM
Extent increase have dropped back from the record breaking values of recent weeks, but are still well above average.
The forecast over the next week has plenty of warm air intrusions and continued strong +ve surface temperature anomalies across much of the Arctic. Ice here is slowly to continue slowing in growth, with the most likely areas of fast growth being the N. American side, CAA, Baffin and Hudson Bay.
Title: Re: The 2020/2021 freezing season
Post by: uniquorn on November 10, 2020, 07:18:45 PM
I referred to this weak area in this post (https://forum.arctic-sea-ice.net/index.php/topic,3299.msg290206.html#msg290206) on Oct 17th. Back then PSL indicated it was only about 20cm thick.
Since then it has only slightly thickened by about 10cm.
The darker area on amsr2 follows the ice movement so would appear to be an ice feature, perhaps some surface interference as cs2smos (oct22-nov7) doesn't show noticeable thinning. (click)
oct28 is missing

Title: Re: The 2020/2021 freezing season
Post by: uniquorn on November 10, 2020, 07:25:39 PM
It would be better to see also the 18GHZ and 37GHz but I don't know if there is an easy way to vizualise this data.<>
JAXA RGB uses 36H, 36V and 18V, nov1-9 shown split into the 3 component greyscale images.
Title: Re: The 2020/2021 freezing season
Post by: Vince O on November 10, 2020, 07:54:30 PM
So here's an image from Polarview, I think the AMSR2 Ice concentration from yesterday (9th Nov). Truthfully I don't know how accurate it is but if so how does everyone think the storm coming in that is due to hit exactly there in the next 48Hrs will have an effect ? According to Climate Reanalyzer it will drop to 967 running up the Greenland coast before having gusts up to 50mph. Earth null school  predicts waves 7m or so between Greenland and Svalbard though it does n't show what they are like nearer the Atlantic side ice edge. Which may not be as thick as could be if the AMSR2 is correct. Just throwing it in there. :@)
Title: Re: The 2020/2021 freezing season
Post by: uniquorn on November 10, 2020, 08:02:06 PM
The very late refreeze was no surprise after the extreme SSTs observed during Aug/Sep. Even the current fast refreeze was not a big surprise as it was bound to happen because air is much colder now than at previous (earlier) refreeze dates.

However, I found it most fascinating that (at least the Siberian side) freezes as if it was a lake: from the shores towards the center. Previously, the Arctic used to (mostly) freeze from the center towards the shores.
Some posters previously speculated that this will be more and more common in the future...it seems so. Amazing to see this happen
Perhaps this "dis-ordered" refreeze also explains why the ice was so quick to retreat from the Laptev shores this past January (and also why it never really refroze in any meaningful way thereafter).

Central ice expanding to shoreline -> thick ice, growing in thickness, to the shoreline.

Central ice stagnant and shore ice expanding to it -> thin ice, expanding in area but not really volume, to the CAB / when the winds blow from the land, this thin ice then retreats TOWARDS the CAB as the ice between it and CAB breaks apart / crumples.
Even in april ice that is normally fast broke up near the Lena delta. Below is viirs brightness temperature from jan26. It refroze again, but would have been weaker. https://go.nasa.gov/3kepk2x
That particular weakness can be dated back to dec28  https://go.nasa.gov/2UecDdo
Title: Re: The 2020/2021 freezing season
Post by: BornFromTheVoid on November 10, 2020, 09:53:45 PM
Had a quick look at the AMSR2 and Sentinel 1 images for the area with the dark patch.
Nothing particularly stands out. The brighter white section in the radar image appears to represent the ice edge at minimum, so some kind of multi-year/first year ice boundary. Perhaps that's playing some kind of role.
The ECM showed surface temps not far off 0C, 850hPa temps around -5C and some precip there late last week. Might have been some sleety rain or something!? Should be well frozen now, but might have effected the emissivity in some way.
Will take a little more digging.
Title: Re: The 2020/2021 freezing season
Post by: aslan on November 10, 2020, 10:21:34 PM
It would be better to see also the 18GHZ and 37GHz but I don't know if there is an easy way to vizualise this data.<>
JAXA RGB uses 36H, 36V and 18V, nov1-9 shown split into the 3 component greyscale images.

Yep, so I decide to take my courage with my hands my two, and to look at the 37 GHz and 18 Ghz polarization. It is for the pass of the 08th of November, at 03 UTC something more or less. There is the horizontal 37 GHz (TB37H), the vertical 37 GHz (TB37V) and the horizontal 18 GHz. And there is the TB37V + TB37H and TB37V - TB37H. Usually, the ratio PR37 = (TB37V + TB37H) / (TB37V - TB37H). Again I'm not sure how JAXA put all of this in the mixer, but usually PR37 is between 0.05 and 0.01 for sea ice. And ice thickness increase with a lower PR37 (at ~0.05 more or less some decimals, we are at about ~20 cms of ice thickness, upper end of the detection). As uniquorn said, they probably also put the 18GHz in the mixer, as there is the TB37V, TB37H and TB18H on their website. With some specious algorithm, and a good deal of luke, we could probably emulate something.
This said.
Actually, there is really something on the 37 GHz, with TB37H being quite low for such a TB37V where JAXA thickness is showing open water. In any case TB37V is way higher than TB37H for water. But here we really have something looking a bit like open water with low TB37H and high TB37V. This leads to a high sum of TB (TB37V+TB37H) and a high difference (TB37V-TB37H). PR37 is the ratio of the two. North of the Svernaïa Zemlaïa, the ratio is something like 40K/450K which is almsot 0.1 while in Laptev the ratio is more like 10K/510K which is about 0.02. The PR37 of 0.1 is way outside of anything known about the ice thickness, so no suprise the algorithm go down to total meltdown... And so the ratio PR37 going trough the sky is exactly where JAXA has a hole. At least, we have the good thread in the hand...
Problem is, physically, I can't conceive that it is not a signal of really liquid water, like, I mean, liquid water. But in the same time, face values of TB37H and TB37V are good for the sea ice.

I have taken the 8th of November because it is a cloud free day and the IR channel allow use to spike at the surface:

https://worldview.earthdata.nasa.gov/?v=182321.86694795976,358462.0295864898,905260.1729350943,702610.7856657819&p=arctic&t=2020-11-08-T02%3A00%3A00Z&l=Coastlines,AMSRU2_Sea_Ice_Concentration_12km(max=30),VIIRS_SNPP_Brightness_Temp_BandI5_Night(hidden,palette=rainbow_2,min=239.6,max=266.5,squash=true),VIIRS_SNPP_Brightness_Temp_BandI5_Day(hidden,palette=rainbow_2,min=239.6,max=266.5,squash=true),VIIRS_NOAA20_Brightness_Temp_BandI5_Night(palette=rainbow_2,min=239.6,max=266.5,squash=true),VIIRS_NOAA20_Brightness_Temp_BandI5_Day(hidden,palette=rainbow_2,min=239.6,max=266.5,squash=true),AMSRU2_Sea_Ice_Brightness_Temp_89V(hidden),AMSRU2_Sea_Ice_Brightness_Temp_89H(hidden),Reference_Labels(hidden),Reference_Features(hidden),VIIRS_NOAA20_CorrectedReflectance_TrueColor(hidden),VIIRS_SNPP_CorrectedReflectance_TrueColor(hidden),MODIS_Aqua_CorrectedReflectance_TrueColor(hidden),MODIS_Terra_CorrectedReflectance_TrueColor

What I find curious is that this high PR is in connection with high IR temperatures. For the 1st and 2nd of November for example, where we can also see a highly fractured ice and open leads, IR temperatures are lower :

https://worldview.earthdata.nasa.gov/?v=245158.89853261935,130120.98769930608,1046101.2498590265,511402.9195286478&p=arctic&t=2020-11-01-T10%3A00%3A00Z&l=Coastlines,AMSRU2_Sea_Ice_Concentration_12km(max=30),VIIRS_SNPP_Brightness_Temp_BandI5_Night(palette=rainbow_2,min=239.6,max=266.5,squash=true),VIIRS_SNPP_Brightness_Temp_BandI5_Day(hidden,palette=rainbow_2,min=239.6,max=266.5,squash=true),VIIRS_NOAA20_Brightness_Temp_BandI5_Night(hidden,palette=rainbow_2,min=239.6,max=266.5,squash=true),VIIRS_NOAA20_Brightness_Temp_BandI5_Day(hidden,palette=rainbow_2,min=239.6,max=266.5,squash=true),AMSRU2_Sea_Ice_Brightness_Temp_89V(hidden),AMSRU2_Sea_Ice_Brightness_Temp_89H(hidden),Reference_Labels(hidden),Reference_Features(hidden),VIIRS_NOAA20_CorrectedReflectance_TrueColor(hidden),VIIRS_SNPP_CorrectedReflectance_TrueColor(hidden),MODIS_Aqua_CorrectedReflectance_TrueColor(hidden),MODIS_Terra_CorrectedReflectance_TrueColor

https://worldview.earthdata.nasa.gov/?v=249857.53638176603,-49112.767427918385,1270724.6748952155,436862.52663525497&p=arctic&t=2020-11-02-T10%3A00%3A00Z&l=Coastlines,AMSRU2_Sea_Ice_Concentration_12km(max=30),VIIRS_SNPP_Brightness_Temp_BandI5_Night(palette=rainbow_2,min=239.6,max=266.5,squash=true),VIIRS_SNPP_Brightness_Temp_BandI5_Day(hidden,palette=rainbow_2,min=239.6,max=266.5,squash=true),VIIRS_NOAA20_Brightness_Temp_BandI5_Night(hidden,palette=rainbow_2,min=239.6,max=266.5,squash=true),VIIRS_NOAA20_Brightness_Temp_BandI5_Day(hidden,palette=rainbow_2,min=239.6,max=266.5,squash=true),AMSRU2_Sea_Ice_Brightness_Temp_89V(hidden),AMSRU2_Sea_Ice_Brightness_Temp_89H(hidden),Reference_Labels(hidden),Reference_Features(hidden),VIIRS_NOAA20_CorrectedReflectance_TrueColor(hidden),VIIRS_SNPP_CorrectedReflectance_TrueColor(hidden),MODIS_Aqua_CorrectedReflectance_TrueColor(hidden),MODIS_Terra_CorrectedReflectance_TrueColor

Excepted where JAXA is showing a melt fraction (in the buldge toward the Zemlya Frantza Yosifa), IR temp are lower.
I am not sure what to make of all of this. It is curious for sure. But overall, if the channel 37 GHz is reacting like there is liquid water, I can't think how this could not be the case.
Title: Re: The 2020/2021 freezing season
Post by: aslan on November 10, 2020, 10:22:51 PM
Er... I still don't know how to make it an other way.
Title: Re: The 2020/2021 freezing season
Post by: aslan on November 10, 2020, 10:34:17 PM
So here's an image from Polarview, I think the AMSR2 Ice concentration from yesterday (9th Nov). Truthfully I don't know how accurate it is but if so how does everyone think the storm coming in that is due to hit exactly there in the next 48Hrs will have an effect ? According to Climate Reanalyzer it will drop to 967 running up the Greenland coast before having gusts up to 50mph. Earth null school  predicts waves 7m or so between Greenland and Svalbard though it does n't show what they are like nearer the Atlantic side ice edge. Which may not be as thick as could be if the AMSR2 is correct. Just throwing it in there. :@)

The Atlantic front will be hit hard for sure. Given the look it has, some massive melt and a big jump northward is even not out of question I fear. Perhaps I am a bit pessimistic, but forecast is looking grim I think. Models are predicting waves of 6 - 7 meters and periods of 10 - 12 seconds north of Svalbard on Thursaday, almost orthogonal to the ice edge. And the same in the Kara sea Friday and Saturday. With the heat advection (forecast are for a good 20mm of rain somewhere over the ice edge) and the wind, the Atlantic front will retreat for sure, but I fear that it could be more like a collapse than just a push to the North. We will see. Laptev is in for a good washing also, by the way. The sea is not closed and if the hole remain open, models are with values of up to 4m and 8 seconds on the 80th North directed against the ice edge...
Title: Re: The 2020/2021 freezing season
Post by: uniquorn on November 10, 2020, 10:39:22 PM
Er... I still don't know how to make it an other way.
If that's panoply then      Map tab -> Center o... Lon. ->  play with °E

Quote
PR37 = (TB37V + TB37H) / (TB37V - TB37H)
edit: can you post a link to the TB37V/H .nc data?

Had a quick look at the AMSR2 and Sentinel 1 images for the area with the dark patch.
Nothing particularly stands out. The brighter white section in the radar image appears to represent the ice edge at minimum, so some kind of multi-year/first year ice boundary. Perhaps that's playing some kind of role.
The ECM showed surface temps not far off 0C, 850hPa temps around -5C and some precip there late last week. Might have been some sleety rain or something!? Should be well frozen now, but might have effected the emissivity in some way.
Will take a little more digging.
Yep, seems to be something to do with the old ice edge. ascat day292-314
Title: Re: The 2020/2021 freezing season
Post by: VeliAlbertKallio on November 11, 2020, 03:37:47 AM
NEW ALL-TIME RECORD STIRRING OF ATLANTIC DEPRESSION SYSTEMS RUNNING NOW IN 30'S

SYSTEM IOTA ON THE GREEK ALPHABET FORMING AS THE 30TH ATLANTIC STORM IN 2020.

THE CURRENT FREEZING SEASON OUGHT TO BE VIEWED AGAINST STORM BACKGROUND:
- vertical mixing of ocean water reducing ice formation
- wind action scattering ice floes and helping to spread ice
- wave action by storms breaking more sea ice
- more transportation of ice potentially out
- other effects on ice formation and destruction

https://www.bbc.co.uk/news/world-us-canada-54887071
Title: Re: The 2020/2021 freezing season
Post by: VeliAlbertKallio on November 11, 2020, 04:05:52 AM
The polar freezing inversion concept that I proposed several years ago as outcome of warmed ocean having too much heat in the deeper waters for ice to begin to form seems starting. We have now entered to the interim phase where there are still remaining sea ice cap at the centre from where outward spreading freezing can still occur, but its melted fringes are situated deep enough waters that they fail to re-freeze quickly due to increased vertical mixing and warmer air. This then sees sea ice advancing both from the centre and from coastal periphery towards the middle parts that are open. Its final and full implementation is once the North Pole is without ice cover, or with one that has detached from the continental margins and pushed aside (lop-sided, misplaced, residual polar sea ice cap). We are, indeed, in a new era and sadly these things are not ending here but come to be from bad to worse.

We at Sea Research Society (SRS) have been for years warning about these developments and never ever we were given grants to develop our ideas before these things were to start happening like now. The next phase is the grumbling of the land ice within years after all sea ice in summers have gone with exhaustively melt water pond and crevasse covered GIS that has turned black from dirt on top of that. We are heading towards next Heindrich Ice Berg Calving (DO) Event with ocean then suddenly loaded with ice debris from gigantic ice debris flows from Greenland, conversion of mantle minerals such as perovskite minerals shutting off magnetic fields and also redirecting magnetic fields, conversion of peridotite and olivine group minerals leading to partial melting events by water incursions from crust. The methane clathrate destabilisation relasing methane and CO2 from seabed and diluting carbon-14 to zero which has mislead many researchers to think deglaciation processes occurring over longer period than they actually did. Hence, the feeling of fast forward movie among many conventional observers. :'( :-\ :-[ ???

https://www.academia.edu/37157851/Our_Changing_Climate_in_Action_the_Risk_of_Global_Warming_and_the_Environmental_Damage_from_the_Rising_Ocean_Water_Table_Sustainable_Seas_Enquiry_Written_evidence_submitted_by_Veli_Albert_Kallio_FRGS_SSI0121_Ordered_to_be_published_23_May_2018_by_the_House_of_Commons

The very late refreeze was no surprise after the extreme SSTs observed during Aug/Sep. Even the current fast refreeze was not a big surprise as it was bound to happen because air is much colder now than at previous (earlier) refreeze dates.

However, I found it most fascinating that (at least the Siberian side) freezes as if it was a lake: from the shores towards the center. Previously, the Arctic used to (mostly) freeze from the center towards the shores.
Some posters previously speculated that this will be more and more common in the future...it seems so. Amazing to see this happen
Perhaps this "dis-ordered" refreeze also explains why the ice was so quick to retreat from the Laptev shores this past January (and also why it never really refroze in any meaningful way thereafter).

Central ice expanding to shoreline -> thick ice, growing in thickness, to the shoreline.

Central ice stagnant and shore ice expanding to it -> thin ice, expanding in area but not really volume, to the CAB / when the winds blow from the land, this thin ice then retreats TOWARDS the CAB as the ice between it and CAB breaks apart / crumples.
Even in april ice that is normally fast broke up near the Lena delta. Below is viirs brightness temperature from jan26. It refroze again, but would have been weaker. https://go.nasa.gov/3kepk2x
That particular weakness can be dated back to dec28  https://go.nasa.gov/2UecDdo
Title: Re: The 2020/2021 freezing season
Post by: uniquorn on November 11, 2020, 10:39:36 AM
jaxa thickness and melt conc, nov 4-10
amsr2 awi v103, atl side, nov 2-10. Temporary lower concentration very widespread, possibly surface change caused by weather. Drifting snow? A rammb interpretation might help.

added gimp division of 37GHzV-H and V+H (both ways) probably meaningless.
Title: Re: The 2020/2021 freezing season
Post by: BornFromTheVoid on November 11, 2020, 06:14:20 PM
A short animation focusing on the October temperature changes in the eastern Arctic.

Title: Re: The 2020/2021 freezing season
Post by: Glen Koehler on November 12, 2020, 02:58:46 AM
       +2.7C per decade is Monstrous.  It is more than 10X the rate of increase in NASA GISS (and other) measures of global average surface temperature.  At risk of being one of those alarmists, +2.7 per decade looks like a possible break out from system equilibrium into scary out-of-control realignment to an entirely new climate regime.  Maybe the fact that it is an October-only single-region value, and not the whole year/whole planet is some cause for not seeing this as an unfolding catastrophe.  If it was a whole year planet-wide rate, we would be into Mad Max territory.  Somebody who actually studies this stuff can correct me if I'm wrong, but +2.7C per decade (he says for the 3rd time in one paragraph) is absolutely nuts and unsustainable within the Holocene climate envelope upon which Human civilization is built and dependent.  At that rate, the Laptev bite is going to be the CAB bite sooner than any of us ever foresaw.

       Some people play fantasy football, I play nightmare planet by tracking NASA GISS and daily Climate Forecast System reports.  Entering 2020, my magic predictive formula (which has been more accurate than UK Met and NASA GISS's Gavin Schmidt's prognostications over the last few years) called for 2020 to be several points (0.01 C units) below 2019, due to a weak ENSO signal and coming off of the bottom of the solar cycle.  But as 2020 winds down, the current end-of-year-average projection has a 95.8% chance of beating 2019, and a 68% chance of topping 2016, the previous record-holder for warmest yearly global average surface temperature.  Keep in mind that 2016 had a strong ENSO and a solar maximum pushing it up.  The graph below shows the annual average GISS with ENSO/Solar/Aerosol forcings removed to see the underlying temperature without variation due to single-year forcings.  (Too bad Tamino is not posting these days, it would be great to read his take on this).

       The last time I sort-of looked, it was hard to see a correlation between annual GISS and ASI Extent/Area/Volume values.  Of course, warming the planet as a whole eventually shows up in the Arctic.  With La Nina kicking in for the next few months, that should put the brakes on GISS increase over the next six months at least, but I have no clue if that would show up in the Arctic or in the ASI stats.  Remember that a cool La Nina year does not mean the Earth system is cooling, just that more heat is going into the ocean vs. the surface atmosphere than in an ENSO-neutral or El Nino year.  Heat in the ocean has a bad habit of melting ice.

       Looking ahead to 2021, based on the ENSO/Solar/Aerosol predictors, the GISS surface air temperature should be slightly cooler than 2020.  But that is from the formula (that explained >80% of year-to-year variability... until 2020) that said 2020 should be cooler than 2019.  The fact that my previously reliable formula failed in 2020 feeds my wonderings if Earth's thermostat is broken, and that the climate system is playing by new rules.

       As for right now, the DMI 80N temperature is starting to look like the winter of 2016-2017 when there was a low accumulation of freezing degree days.  Going out on the limb of my ignorance, I'll hazard a guess that for the near term at least, the recent above-average increases in Extent and Area could lose some momentum.  If that DMI anomaly does not fall, it is easy to imagine a new record low maximum in spring 2021.
Title: Re: The 2020/2021 freezing season
Post by: binntho on November 12, 2020, 05:41:09 AM
Glen, your posting is not the easiest read with the morning coffee, with a shiver down the spine replacing that warm feeling in the belly.
Title: Re: The 2020/2021 freezing season
Post by: Aluminium on November 12, 2020, 06:57:36 AM
November 2-11.

2019 (https://forum.arctic-sea-ice.net/index.php/topic,2888.msg236300.html#msg236300).
Title: Re: The 2020/2021 freezing season
Post by: jdallen on November 12, 2020, 08:18:51 AM
       +2.7C per decade is Monstrous.
<snippage>
Going out on the limb of my ignorance, I'll hazard a guess that for the near term at least, the recent above-average increases in Extent and Area could lose some momentum.  If that DMI anomaly does not fall, it is easy to imagine a new record low maximum in spring 2021.
You and I have similar hobbies, but I think yours is further evolved and more detailed.

Oh, without question 2.7c is monstrous, and I'm very much of the opinion we are in the middle of a "tip over" into a new climate regime.

As to the recent century and multiple century extent and area increases - they neither surprised me nor reassured me.  Quite the contrary, they represent heat getting locked in, and the exchange of ocean heat with atmosphere slowing down.

They will without question slow down - as the areas of "hot" open water become farther removed from areas with persistent low temperatures.  By the end of the season, most of these will still freeze - the Chukchi, & Kara for example, and probably the Okhotsk - but the Bering and Barents will likely remain significantly ice free for the duration.

Mostly I think this will be driven primarily from the fact we will have little or no circulation which isolates the Arctic from inflows from lower latitude.  I think we are set up currently to it set up much like 2016, and the recent flows from tropical storms have persistently carried moisture and heat across the Barents into the Kara and then around into the Laptev and central basin.  (see my previous post with a capture from Climate Reanalyzer).

There are similar but less talked about intrusions of heat on the Pacific side, which are blowing across Kamchatka and into the Bering and Chukchi.  I don't see these patterns breaking down soon.
Title: Re: The 2020/2021 freezing season
Post by: gerontocrat on November 12, 2020, 10:51:30 AM
       +2.7C per decade is Monstrous.
<snippage>
Going out on the limb of my ignorance, I'll hazard a guess that for the near term at least, the recent above-average increases in Extent and Area could lose some momentum.  If that DMI anomaly does not fall, it is easy to imagine a new record low maximum in spring 2021.
You and I have similar hobbies, but I think yours is further evolved and more detailed.

Oh, without question 2.7c is monstrous, and I'm very much of the opinion we are in the middle of a "tip over" into a new climate regime.

As to the recent century and multiple century extent and area increases - they neither surprised me nor reassured me.  Quite the contrary, they represent heat getting locked in, and the exchange of ocean heat with atmosphere slowing down.

They will without question slow down - as the areas of "hot" open water become farther removed from areas with persistent low temperatures. 
I attach a graph of daily extent change for the freezing season. I have used a 7 day trailing average to make the graph less noisy. Extent gains are quickly heading back down to something like average.

It makes it clear, at least to me, that the extreme extent gains were an almost inevitable consequence of previous very low extent gains from a very low minimum. On the 24th October extent gains from minimum were just over 1 million less than the 10 year average. By November 10th, 275k above average. It is also clear that compared with the other years of very low minimums (apart from 2016), sea ice extent recovery rebound happened later.

What happens next? My eyes are pretty much glued to the Atlantic Front, though with the ESS and the Beaufort now pretty much full-up ice, looking for resistance to freeze in the Chukchi is also a distraction.
________________________________________________________
ps: From Aluminimum's latest gif it looks like the last bit of the Laptev to freeze will be the hole centred on 80 North.
Title: Re: The 2020/2021 freezing season
Post by: El Cid on November 12, 2020, 12:09:14 PM
       +2.7C per decade is Monstrous. 

You ain't seen nothing yet. 10 C in 1-3 years IS monstrous and that did happen at the end of the last glacial and then again with beginning and end of the Younger Dryas:

"The high-resolution records from the NGRIP
ice core reveal that polar atmospheric circulation
can shift in 1 to 3 years,
resulting in decadal- to
centennial-scale changes from cold stadials to
warm interstadials/interglacials associated with
large Greenland temperature changes of 10 K

(6, 20). Neither the magnitude of such shifts nor
their abruptness is currently captured by state-ofthe-
art climate models.
"

https://www.researchgate.net/publication/5288829_High-Resolution_Greenland_Ice_Core_Data_Show_Abrupt_Climate_Change_Happens_in_Few_Years
Title: Re: The 2020/2021 freezing season
Post by: uniquorn on November 12, 2020, 12:49:34 PM
Yep, so I decide to take my courage with my hands my two, and to look at the 37 GHz and 18 Ghz polarization. It is for the pass of the 08th of November, at 03 UTC something more or less. There is the horizontal 37 GHz (TB37H), the vertical 37 GHz (TB37V) and the horizontal 18 GHz. And there is the TB37V + TB37H and TB37V - TB37H. Usually, the ratio PR37 = (TB37V + TB37H) / (TB37V - TB37H). Again I'm not sure how JAXA put all of this in the mixer, but usually PR37 is between 0.05 and 0.01 for sea ice. And ice thickness increase with a lower PR37 (at ~0.05 more or less some decimals, we are at about ~20 cms of ice thickness, upper end of the detection). As uniquorn said, they probably also put the 18GHz in the mixer, as there is the TB37V, TB37H and TB18H on their website. With some specious algorithm, and a good deal of luke, we could probably emulate something.
This said.
Actually, there is really something on the 37 GHz, with TB37H being quite low for such a TB37V where JAXA thickness is showing open water. In any case TB37V is way higher than TB37H for water. But here we really have something looking a bit like open water with low TB37H and high TB37V. This leads to a high sum of TB (TB37V+TB37H) and a high difference (TB37V-TB37H). PR37 is the ratio of the two. North of the Svernaïa Zemlaïa, the ratio is something like 40K/450K which is almsot 0.1 while in Laptev the ratio is more like 10K/510K which is about 0.02. The PR37 of 0.1 is way outside of anything known about the ice thickness, so no suprise the algorithm go down to total meltdown... And so the ratio PR37 going trough the sky is exactly where JAXA has a hole. At least, we have the good thread in the hand...
Problem is, physically, I can't conceive that it is not a signal of really liquid water, like, I mean, liquid water. But in the same time, face values of TB37H and TB37V are good for the sea ice.
<snip links +>
I am not sure what to make of all of this. It is curious for sure. But overall, if the channel 37 GHz is reacting like there is liquid water, I can't think how this could not be the case.

It's possible that they are areas of wet snow.


Dielectric properties of snow in the 3 to 37 GHz range (https://ieeexplore.ieee.org/abstract/document/1143757)
M. Hallikainen; F. Ulaby; M. Abdelrazik  Date of Publication: November 1986
https://ieeexplore.ieee.org/abstract/document/1143757
Quote
Abstract:
Microwave dielectric measurements of dry and wet snow were made at nine frequencies betweeo 3 and 18 GHz, and at 37 GHz, using two free-space transmission systems. The measurements were conducted during the winters of 1982 and 1983. The following parametric ranges were covered: 1) liquid water content, 0 to 12.3 percent by volume; 2) snow density, 0.09 to 0.42 g cm -3 ; 3) temperature, 0 to -5 \deg C and -15\deg C (scattering-loss measurements); and 4) crystal size, 0.5 to 1.5 mm. The experimental data indicate that the dielectric behavior of wet snow closely follows the dispersion behavior of water. For dry snow, volume scattering is the dominant loss mechanism at 37 GHz. The applicability of several empirical and theoretical mixing models was evaluated using the experimental data. Both the Debye-like semi-empirical model and the theoretical Polder-Van Santen mixing model were found to describe adequately the dielectric behavior of wet snow. However, the Polder-Van Santen model provided a good fit to the measured values of the real and imaginary parts of wet snow only when the shapes of the water inclusions in snow were assumed to be both nonsymmetrical and dependent upon snow water content. The shape variation predicted by the model is consistent with the variation suggested by the physical mechanisms governing the distribution of liquid water in wet snow.

The role of snow on microwave emission and scattering over first-year sea ice (https://ieeexplore.ieee.org/abstract/document/718643)
D.G. Barber; A.K. Fung; T.C. Grenfell; S.V. Nghiem; R.G. Onstott; V.I. Lytle; D.K. Perovich; A.J. Gow
Date of Publication: Sep 1998  (paywall)
Quote
Abstract:
Investigates the geophysical and thermodynamic effects of snow on sea ice in defining the electromagnetic (EM) interaction within the microwave portion of the spectrum. The authors combine observational evidence of both the physical and thermodynamic characteristics of snow with direct measurements of scattering and emission at a variety of frequencies. They explain their observational results using various "state-of-the-art" forward scattering and emission models. Results show that geophysical characteristics of snow effect emission above about 37 GHz and above 5 GHz for active microwave scattering. They understand these effects to be driven by grain size and its contribution to volume scattering in both passive and active interactions within the volume. With snow cover, the Brewster angle effect is not significant and there is a gradual rise in emission from 10 to 37 GHz. They find emissivity to be dominated by direct emission from saline ice through the snow layer. Hence, the influence of grain size is small but the trend is clearly a drop in total emission as the grain size increases. They find that the role of the volume fraction of snow on emission and scattering is a complex relationship between the number density of scatterers relative to the coherence of this scattering ensemble. At low volume fractions, they find that independent scattering dominates, resulting in an increase in albedo and the extinction coefficient of the snow with frequency. The thermodynamic effects of snow on microwave scattering and emission are driven by the role that thermal diffusivity and conductivity play in the definition of brine volumes at the ice surface and within the snow volume. Prior to the presence of water in liquid phase within the snow volume, they find that the indirect effects are dominated by an impedance matching process across the snow-ice interface. They find that the complex permittivity at the snow-ice interface is considerably higher than over the bare ice surface.

open access doc for some background
Thin sea ice thickness as inferred from passive microwave and in situ observations (https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2007JC004270)
Kazuhiro Naoki, Jinro Ukita, Fumihiko Nishio, Masashige Nakayama, Josefino C. Comiso, Al Gasiewski
First published: 19 February 2008

https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/JC091iC04p05133
Variations in brightness temperature over cold first‐year sea ice near Tuktoyaktuk, Northwest Territories
A. W. Lohanick, T. C. Grenfell.    First published: 15 April 1986
Quote
Abstract

Microwave radiometric temperature (TB) profiles of first‐year sea ice were obtained along 70‐ to 100‐m traverses, with sled‐mounted radiometers at 10, 18.7, 33.6, and 37 GHz and an effective spot size of 30 cm. Measurements of TB as a function of nadir angle were obtained at selected sites along the traverses. Snow and ice properties were recorded and correlated with the TB measurements to infer the effect of snow cover and ice conditions on the radiometric temperature. TB correlated positively with the brine volume profile in the ice at several sites, suggesting that brine volume has a strong effect on TB under these conditions. An overall statistical comparison of snow thickness with TB, when compared with previously published models, suggests that the effect of snow cover on the microwave transmission coefficient of the snow/ice interface may be an important contribution to the radiometric temperature at these frequencies. A model is proposed to explain the data.
Title: Re: The 2020/2021 freezing season
Post by: binntho on November 12, 2020, 01:49:21 PM
       +2.7C per decade is Monstrous. 

You ain't seen nothing yet. 10 C in 1-3 years IS monstrous and that did happen at the end of the last glacial and then again with beginning and end of the Younger Dryas:
The Younger Dryas event was mostly limited to the Northern Hemisphere. Greenland ice cores can only show what is happening in and around Greenland, and the 10 degree jump in a few years is probably a local event due the the NAO restarting after a total standstill, and not, as some people mistakenly think, a global warming event.

Besides, 10 degrees global in 1-3 years? I doubt if it is physically possible given the inputs we are dealing with, and the same probably goes for 2.7 degrees every decade on a global scale. The inputs are not big enough to cause so rapid a temperature increase, and I doubt if any earth system could change fast enough to cause a 10 (actually closer to 20) fold increase in the current rate of warming.
Title: Re: The 2020/2021 freezing season
Post by: El Cid on November 12, 2020, 01:57:36 PM
The Younger Dryas event was mostly limited to the Northern Hemisphere. Greenland ice cores can only show what is happening in and around Greenland,

Yes. He (Glen) was talking about localized effects, and the study I  attached is also localized (Greenland). Apples to apples. Definitely not talking about global change
Title: Re: The 2020/2021 freezing season
Post by: grixm on November 12, 2020, 02:17:28 PM
The freezing days anomaly has been following the record 2016 very closely so far.
Title: Re: The 2020/2021 freezing season
Post by: binntho on November 12, 2020, 02:31:19 PM
The Younger Dryas event was mostly limited to the Northern Hemisphere. Greenland ice cores can only show what is happening in and around Greenland,

Yes. He (Glen) was talking about localized effects, and the study I  attached is also localized (Greenland). Apples to apples. Definitely not talking about global change
Indeed!
Title: Re: The 2020/2021 freezing season
Post by: BornFromTheVoid on November 12, 2020, 03:53:37 PM
Cumulative extent anomaly remains the lowest on record. Whether it can maintain that position over 2016 remains to be seen though
Title: Re: The 2020/2021 freezing season
Post by: romett1 on November 12, 2020, 04:34:06 PM
Meanwhile new November record of 9.4 °C was just broken for Svalbard (previous record was 7.5 °C).

https://thebarentsobserver.com/en/climate-crisis/2020/11/record-november-warmth-svalbard
Title: Re: The 2020/2021 freezing season
Post by: uniquorn on November 12, 2020, 08:51:07 PM
~7days raw buoy data from iabp (https://iabp.apl.uw.edu/maps_daily_table.html)
drift and surface temperature (some sea, some ice, some faulty, NA don't report temp) 9MB. Click twice for full res.

Still some movement in the Mclure Strait. Drift direction changing along the Alaskan coast.

adding 7m-250m temperature and salinity from whoi itp121. 50m temperature remains high along that drift path in the Beaufort. The white areas on the temperature profile are over 1.8C. Click the chart for daily detail.
Title: Re: The 2020/2021 freezing season
Post by: Positive retroaction on November 12, 2020, 11:13:40 PM
And is it normal or worrying that the area from -0.4 to 1.8 is widening at this time of year? Is it heat that the halocline lets through?
And the same question for the increase in white areas, after the day 300
Title: Re: The 2020/2021 freezing season
Post by: uniquorn on November 13, 2020, 12:41:24 AM
Is it normal?                   Recently it seems that it is.
Does it affect surface?   It seems not much at the moment

Beaufort 50m temperatures from whoi itp buoys, 2006-oct2020

previously discussed here (https://forum.arctic-sea-ice.net/index.php/topic,3017.msg288031.html#msg288031)
Title: Re: The 2020/2021 freezing season
Post by: Vince O on November 13, 2020, 12:58:09 AM
Storm has left its trail and maybe another one in 4 days time. Pushed all that ice back in Fram Strait.
Title: Re: The 2020/2021 freezing season
Post by: vox_mundi on November 13, 2020, 12:58:26 AM
(https://i.kinja-img.com/gawker-media/image/upload/c_fill,f_auto,fl_progressive,g_center,h_675,pg_1,q_80,w_1200/zu8y12qvekjaisrn9j0e.gif)

..., Svalbard hit a record high temperature for November on Wednesday. A station set on the mountain pass of Reindalspasset recorded a high of 49 degrees Fahrenheit (9.4 degrees Celsius). That is, to put it lightly, extremely not normal and very bad

https://twitter.com/Ketil_Isaksen/status/1326768433577537536

The temperature is a November record for the entire archipelago that sits well above the Arctic Circle. While the station was installed just last October, Svalbard weather data extends back to the start of the 20th century. Other weather stations scattered across the islands all recorded temperatures well into the 40s as well, underscoring just how widespread the heat was. For perspective, the average November temperature at Svalbard’s airport, home to the longest-running temperature record on the island, is 17.6 degrees Fahrenheit (minus-8.8 degrees Celsius).
Title: Re: The 2020/2021 freezing season
Post by: uniquorn on November 13, 2020, 01:27:59 AM
Storm has left its trail and maybe another one in 4 days time. Pushed all that ice back in Fram Strait.
JAXA melt ice concentration may need careful interpretation.

amsr2 awi v103, nov11-12
ftp://ftp.awi.de/sea_ice/product/amsr2/v103/nh/
Title: Re: The 2020/2021 freezing season
Post by: Vince O on November 13, 2020, 06:10:26 AM
For sure, though I'm curious to when each part /segment of the JAXA / AMSR2 satalitte scan is made and also what time of day the composites of any other images or readings are made. ie. was it early on in the storm when there was least damage  or later when there was more damage. Suppose we won't know the full picture (excuse the pun) until tomorrow really when we see a full 24 hours after the storm for all the images. But you are right. Though what it shows I think is the ice has been broken up more than swept away. All those big waves
Title: Re: The 2020/2021 freezing season
Post by: UCMiami on November 13, 2020, 08:08:23 PM
I attach a graph of daily extent change for the freezing season. I have used a 7 day trailing average to make the graph less noisy. Extent gains are quickly heading back down to something like average.

It makes it clear, at least to me, that the extreme extent gains were an almost inevitable consequence of previous very low extent gains from a very low minimum. On the 24th October extent gains from minimum were just over 1 million less than the 10 year average. By November 10th, 275k above average. It is also clear that compared with the other years of very low minimums (apart from 2016), sea ice extent recovery rebound happened later.

What happens next? My eyes are pretty much glued to the Atlantic Front, though with the ESS and the Beaufort now pretty much full-up ice, looking for resistance to freeze in the Chukchi is also a distraction.
________________________________________________________
ps: From Aluminimum's latest gif it looks like the last bit of the Laptev to freeze will be the hole centred on 80 North.
Thanks for clearly stating the big picture of ice growth toward maximum. People get caught up in the daily fluctuations and which year is lowest/highest and where the current year ranks for Nov 13 or Oct 30 and while it is interesting and does have some consequences in terms of long term trends and volume growth, the reality is the path from minimum to Dec 31 is currently preordained as far as the CAB, Laptev, Beaufort, and ESS are concerned - they will go from whatever minimum they achieved in Sept. extent to nearly 100% at Dec31. The variations in extent at Dec31 will depend on other seas and the variations will likely not be manifested until later in the year than mid-November.

What you point out and I am trying to emphasize is whether the freezing season starts fast or slow, is an even progression or has wild swings in gain and even periods of loss, the end point of the first phase is pretty well a given and a near record or record low minimum will have a near record or record first three months of refreeze during this current state of the arctic. This year had a very slow start from a second place minimum so a period of very fast growth was inevitable, as it has been in other years. As the graph you posted shows, while the timing was late, it was almost a carbon copy of similar peaks in 2007, 2012, and 2019 - The only outlier is 2016 which had a very early minimum and a very very slow refreeze.

There will sometime in the future be a paradigm shift when one or more than one of the above seas does not completely refreeze. That has already happened with the Baring, Barents and is happening with the Kara and Chukchi. Whether the shift is first seen in a freezing season, or is preceded by a new record minimum is unpredictable.
Title: Re: The 2020/2021 freezing season
Post by: Positive retroaction on November 13, 2020, 09:57:06 PM
Today there is a very strong anomaly at vize Island, +13.8 ° C, the strongest anomaly of this exceptional and unprecedented period which now began several months ago o' the island
Tomorrow we will see how high the anomaly will be
I will make a summary as precise as my possibilities when the ice floe finally reaches the island.
Title: Re: The 2020/2021 freezing season
Post by: uniquorn on November 13, 2020, 11:05:58 PM
Following up on whoi itp121 up thread, here are the charts and drift path for itp120 which is a little further north. The warm layer here at ~50m is not so pronounced and salinity is not high enough to be atlantic water which would probably be deeper in the basin anyway.
It's likely that itp120 and itp121 may have been deployed in those locations hoping to monitor pacific incoming from the chukchi plateau, in which case someone has done their homework very well.

whoi itp120 profile and location.
mercator (model) salinity at 34m, pacific side, sep2018-nov2020
full arctic animation here (https://forum.arctic-sea-ice.net/index.php/topic,2417.msg293234.html#msg293234)

Title: Re: The 2020/2021 freezing season
Post by: gandul on November 13, 2020, 11:23:37 PM
Atlantification of the Beaufort or the Western CAB sounds very.... improbable? (I was going to say impossible)
<Moderation-related comment removed. O>
Title: Re: The 2020/2021 freezing season
Post by: uniquorn on November 14, 2020, 12:54:52 AM
Atlantification of the Beaufort or the Western CAB sounds very.... improbable? (I was going to say impossible)
I suspect that you know that Atlantic water and Atlantification are different things but just in case.


 
Title: Re: The 2020/2021 freezing season
Post by: BornFromTheVoid on November 14, 2020, 12:36:37 PM
Slow sea ice animation, November 6th to 13th. Large file, so click to play
Title: Re: The 2020/2021 freezing season
Post by: Positive retroaction on November 14, 2020, 03:22:53 PM
Vize anomaly is +16,5°C and tonight maybe highter
Title: Re: The 2020/2021 freezing season
Post by: bbr2315 on November 14, 2020, 03:48:11 PM
The extent of the refreeze in Hudson Bay for the current date appears to be unprecedented for the satellite era (although Foxe may be a bit behind the banner year of 2015, the western and southern sides of Hudson are.... advanced). Ice is now forming out in the open Bay hundreds of miles from shore.

This is likely going to result in the earliest refreeze of Hudson Bay in the satellite record since 1999 in EOSDIS, maybe vying with 2018. The 00z EURO shows the North American tropospheric polar vortex steadily intensifying through the end of the run in terms of its scope and depth, and by D10 it is very unseasonably cold over much of the interior / elevated continent.

(https://www.tropicaltidbits.com/analysis/models/ecmwf/2020111400/ecmwf_T850_namer_4.png)

This very unseasonably early freeze up will have some implications as all the heat release is going to be distributed polewards / probably eastwards, into Greenland, Barentz, CAB, etc. As Hudson finishes freezing the North American ice front will extend rapidly into the Great Lakes and St. Lawrence / NW NATL come December and January. Will parts of Kara and Laptev still be open by then? We shall see, but I suspect this anomalous refreeze on both sides of the ATL is getting increasingly worse in the early direction in NAmerica (abetted by its largest-ever snowcover departure seen this October) and the opposite seems to be happening in Eurasia.

(https://ice-glaces.ec.gc.ca/prods/WIS31CT/20201113180000_WIS31CT_0011319476.gif)
Title: Re: The 2020/2021 freezing season
Post by: oren on November 14, 2020, 08:44:34 PM
And yet bbr, according to AMSR2 Hudson Bay has barely reached 100k km2, more than two weeks after 2015 and 2018 and almost the latest in the AMSR2 record. So I think you are basing your predictions on something that is not accurate.
Title: Re: The 2020/2021 freezing season
Post by: Positive retroaction on November 14, 2020, 10:15:52 PM


On Kara, vize, the lowest temperature of the month, -8.5 ° C, is more than 10 ° C above the average temperature of a normal month of November (-18.5 ° C)
Even if we are on the half of the month, is very impresive

Indeed, it seems far from being a record of extent or precocity
Hudson for nsidc
Title: Re: The 2020/2021 freezing season
Post by: bbr2315 on November 14, 2020, 10:48:39 PM
And yet bbr, according to AMSR2 Hudson Bay has barely reached 100k km2, more than two weeks after 2015 and 2018 and almost the latest in the AMSR2 record. So I think you are basing your predictions on something that is not accurate.
There is cloud interference and Foxe Basin is what accounts for those years as I explained in my post.

Here is 12z EURO 00z hr vs D10. I think it will freeze a bit faster and more solidly than modeled.

Title: Re: The 2020/2021 freezing season
Post by: Aluminium on November 15, 2020, 07:42:39 AM
November 9-14.

2019 (https://forum.arctic-sea-ice.net/index.php/topic,2888.msg236796.html#msg236796).
Title: Re: The 2020/2021 freezing season
Post by: Positive retroaction on November 15, 2020, 01:19:50 PM
November 9-14.

2019 (https://forum.arctic-sea-ice.net/index.php/topic,2888.msg236796.html#msg236796).
It's nice to see an ice floe again connected to the eastern lands (even if I m conscient that is dramatic to have this situation so late on the freeze season)
The wait was so long that this image became a memory
It doesn't bring much but I just share an impression
Title: Re: The 2020/2021 freezing season
Post by: grixm on November 15, 2020, 02:02:37 PM
Daily area dropped today, for the first time in almost a month.
Title: Re: The 2020/2021 freezing season
Post by: Pagophilus on November 15, 2020, 02:35:55 PM
NSIDC Spatial Ice Extent comparison     Nov 13 2020 vs Nov 13 2019, 2016, 2012

As the plots of ice extent converge on the graphs, so does the ice's geographical distribution look more and more similar. 

Eyeballing 2020-2016 map, 2016's current #1 status looks to be largely due to its slower refreeze in the northern Kara Sea.

2012, which forms almost an overlay with 2020, would also be in the running with it's slow refreeze of the northern Kara, but it isn't because much of the Chukchi froze over by Nov 13.

Title: Re: The 2020/2021 freezing season
Post by: NotaDenier on November 15, 2020, 02:43:03 PM
I was wondering if there is a way to see how “full” the 7 central arctic seas are compared to the periphery seas. I looked Wipenus’s home brew and guesstimate 90% of the arctic ocean is now covered. With only the Chukchi and the Kara Sea having room for growth.

What I am getting it is, would it be worth figuring out the date the central seas are completely iced over?

Most growth from now will be in the periphery seas, this growth does not effect the end result of the melting season. (Or effects it very little)
Title: Re: The 2020/2021 freezing season
Post by: uniquorn on November 15, 2020, 02:49:46 PM
amsr2 awi v103, nov14 overlaid onto gmrt bathymetry. (click)
While the ice is still thin it is possible to discern some ocean activity.

Leads north of the chukchi align with the shelf break and chukchi plateau topography where sinking Pacific water causes turbulence and possible mixing.
The remaining open water in the Laptev sits over the shear zone at the eastern edge of the Nansen basin. This is where incoming atlantic water is forced to turn back towards the Fram or attempt to rise up the shelf. Note also the low concentration ice along the shelf break north of SZ.

Some incoming Atlantic water from the Barents limits refreeze in the Kara to the fresher surface layer in the shallower coastal area but most continues north, sinking into the St Anna trough between SZ and FJL.

Most Atlantic water enters via the Fram strait, passing to the north of Svalbard and FJL, sinking along the shelf as it moves east.

https://www.nature.com/scitable/knowledge/library/arctic-ocean-circulation-going-around-at-the-102811553/
Title: Re: The 2020/2021 freezing season
Post by: gerontocrat on November 15, 2020, 04:13:03 PM
Today's a warm day on the Atlantic Front
Title: Re: The 2020/2021 freezing season
Post by: jdallen on November 15, 2020, 11:03:50 PM
Today's a warm day on the Atlantic Front
This has been a consistent pattern since the start of the refreeze.  It's been book-ended by cold air being flushed out of the Arctic, breaking south across the Canadian shield into the US great plains.

Here's the September anomaly map from Climate Reanalyzer.  I'll be interested to see Octobers when it turns up, and Nov. after that to see if my hunch is borne out.

(https://climatereanalyzer.org/reanalysis/monthly_maps/output/ncep1/ncep1_arc-lea_t2_sep_2020_minus_1979-2000_af.png)
Title: Re: The 2020/2021 freezing season
Post by: Pagophilus on November 16, 2020, 01:09:23 AM
I was wondering if there is a way to see how “full” the 7 central arctic seas are compared to the periphery seas. I looked Wipenus’s home brew and guesstimate 90% of the arctic ocean is now covered. With only the Chukchi and the Kara Sea having room for growth.

What I am getting it is, would it be worth figuring out the date the central seas are completely iced over?

Most growth from now will be in the periphery seas, this growth does not effect the end result of the melting season. (Or effects it very little)
I can't offer data (much too far down the food chain) but here is the NSIDC comparison map showing all the peripheral seas for Nov 13, 2020 vs Nov 13, 2019.  Hope it helps a bit. 
Title: Re: The 2020/2021 freezing season
Post by: oren on November 16, 2020, 02:36:35 AM
Wipneus comes to the rescue with his pair of useful charts, multi-product Arctic Basin area and extent.

(https://sites.google.com/site/arctischepinguin/home/amsr2/grf/basin-area-multiprod.png)

(https://sites.google.com/site/arctischepinguin/home/amsr2/grf/basin-extent-multiprod.png)
Title: Re: The 2020/2021 freezing season
Post by: Cook on November 16, 2020, 02:51:55 AM
Just a question in the hope someone can answer it easily. Is this the first time in known history that the area around Franz Josef Land is ice free in mid November?
Title: Re: The 2020/2021 freezing season
Post by: oren on November 16, 2020, 03:21:50 AM
So, a quick visit to Worldview can help answer the question.
Sample Worldview link (https://worldview.earthdata.nasa.gov/?v=-1068702.9198780528,-665841.2226054955,2834494.505055002,1099745.737579066&p=arctic&t=2020-11-13-T21%3A55%3A43Z&i=1&l=SSMIS_Sea_Ice_Concentration,Coastlines,Graticule(hidden),VIIRS_SNPP_CorrectedReflectance_BandsM11-I2-I1(hidden),VIIRS_SNPP_CorrectedReflectance_BandsM3-I3-M11(hidden),VIIRS_SNPP_CorrectedReflectance_TrueColor(hidden),MODIS_Aqua_CorrectedReflectance_TrueColor(hidden),MODIS_Aqua_CorrectedReflectance_Bands721(hidden),MODIS_Terra_CorrectedReflectance_TrueColor,MODIS_Terra_CorrectedReflectance_Bands367(hidden),MODIS_Terra_CorrectedReflectance_Bands721(hidden))
Choose Add Layers - Sea Ice - SSMI - Sea Ice Concentration. Now you can see sea ice extent all the way to 1978, and even better you can click the video camera icon to make an animation of up to 40 frames, with 1 year increments showing you the same date every year. Download the result, and upload to ezgif.com for some optimization, resizing and setting desired delays between frames.
And the answer: It seems 2012 was worse.

Click to animate.
Title: Re: The 2020/2021 freezing season
Post by: Cook on November 16, 2020, 03:31:36 AM
Amazing, a big thank you.
Title: Re: The 2020/2021 freezing season
Post by: El Cid on November 16, 2020, 07:17:34 AM
Here's the September anomaly map from Climate Reanalyzer.  I'll be interested to see Octobers when it turns up, and Nov. after that to see if my hunch is borne out.

wait no more:
Title: Re: The 2020/2021 freezing season
Post by: El Cid on November 16, 2020, 07:32:26 AM
and this one is November so far(1st pic):

warm Eurasia (trend continues from Sept/Oct, likely due to open Siberian seas), cold Canada (bbr likes this) and warm US.

...during the past three years we had open siberian seas for very long and the pattern for October for these three years is similar (2nd pic), probably not a coincidence that Eurasia was very warm and NA cold
Title: Re: The 2020/2021 freezing season
Post by: romett1 on November 16, 2020, 07:49:02 AM
Today's a warm day on the Atlantic Front
And nice 7 - 9 m waves most of today.
Title: Re: The 2020/2021 freezing season
Post by: SimonF92 on November 16, 2020, 11:31:33 AM
Ran the regional script again
Title: Re: The 2020/2021 freezing season
Post by: Shared Humanity on November 16, 2020, 01:49:51 PM
Today's a warm day on the Atlantic Front

Must be coming with some high winds too.
Title: Re: The 2020/2021 freezing season
Post by: bbr2315 on November 16, 2020, 04:59:29 PM
Here's the September anomaly map from Climate Reanalyzer.  I'll be interested to see Octobers when it turns up, and Nov. after that to see if my hunch is borne out.

wait no more:
The "triangle of cold" is perfectly illustrated here...

Canuck maps show Hudson refreeze is progressing rapidly, I anticipate the evacuation of all this heat / release of heat associated with freezing will deal the ATL front continued blows for the next few weeks, I would not be surprised to see the front retreat dramatically in Kara / Laptev / Barentz vicinity.
Title: Re: The 2020/2021 freezing season
Post by: oren on November 16, 2020, 09:36:23 PM
Hudson Bay sea ice area according to AMSR2. Progressing rapidly perhaps, but not quite as rapidly as other years.
Title: Re: The 2020/2021 freezing season
Post by: romett1 on November 16, 2020, 10:08:38 PM
Canuck maps show Hudson refreeze is progressing rapidly, I anticipate the evacuation of all this heat / release of heat associated with freezing will deal the ATL front continued blows for the next few weeks, I would not be surprised to see the front retreat dramatically in Kara / Laptev / Barentz vicinity.
Hudson and areas surrounding it are indeed forecasted to be much colder than average. And everything between Bering Sea and Barents Sea (including Beaufort) is relatively warm (7 day forecast mean).
Title: Re: The 2020/2021 freezing season
Post by: Positive retroaction on November 17, 2020, 12:16:20 PM
19,5 °C positive anomaly yesterday on Golomyanny island

18,4°C positive anomaly on vize island
Title: Re: The 2020/2021 freezing season
Post by: Pagophilus on November 17, 2020, 02:38:49 PM
19,5 °C positive anomaly yesterday on Golomyanny island

18,4°C positive anomaly on vize island
Thank you Positive retroaction.  Startling figures.  From my point of view, it would be great to know the absolute temperatures as well.   
Title: Re: The 2020/2021 freezing season
Post by: Positive retroaction on November 17, 2020, 03:28:20 PM
19,5 °C positive anomaly yesterday on Golomyanny island

18,4°C positive anomaly on vize island
Thank you Positive retroaction.  Startling figures.  From my point of view, it would be great to know the absolute temperatures as well.

Yes, it's true
In golomany, yesterday had a minimum temperature of -3.5 ° C, an average temperature of -1.3 ° C and a maximum temperature of -0.9 ° C
On that day, November 17, the normal temperature was -21.5 ° C.

For the island of vize, the minimum temperature yesterday was -5.5 ° C
The average temperature was -0.3 ° C
The maximum 0.1 ° C
The normal average temperature is -18.7 ° C

More generally, anomalies between 9 and 11 degrees last for more than 1 month without stopping
Title: Re: The 2020/2021 freezing season
Post by: SimonF92 on November 17, 2020, 03:35:14 PM
ECMWFs recently publicly available charts are a good way to view these data

https://apps.ecmwf.int/webapps/opencharts/products/medium-2mt-wind30?base_time=202011170000&projection=opencharts_arctic&valid_time=202011170000
Title: Re: The 2020/2021 freezing season
Post by: aslan on November 17, 2020, 06:50:42 PM
19,5 °C positive anomaly yesterday on Golomyanny island

18,4°C positive anomaly on vize island
Thank you Positive retroaction.  Startling figures.  From my point of view, it would be great to know the absolute temperatures as well.

Yes, it's true
In golomany, yesterday had a minimum temperature of -3.5 ° C, an average temperature of -1.3 ° C and a maximum temperature of -0.9 ° C
On that day, November 17, the normal temperature was -21.5 ° C.

For the island of vize, the minimum temperature yesterday was -5.5 ° C
The average temperature was -0.3 ° C
The maximum 0.1 ° C
The normal average temperature is -18.7 ° C

More generally, anomalies between 9 and 11 degrees last for more than 1 month without stopping

To be fully exhaustive, August and September were more extreme than November as far as gap from the normal is considered. At Ostrov Vize, November 2020 is lagging a bit behind November 2016 for now, and no new record as been registered. Way above normal, but still within the (temporarily and for now...) known climatology. At Kotel'Nyj or Mys Tchelouskine there is a higher chance that November could be a record (especially Kotel'Nyj actually), but we are not fully at the same level of extreme than in 2016 overall. This said, winds are also in play. Even though no new wind record as been set to my knowledge, the Atlantic front has been battered for sure. Probably the most noteworthy is Ostrov Heiss with wind speed up to 30 m/s... The sea ice has been damaged, being highly fractured and locally reduced to a crumble of tiny floes : https://worldview.earthdata.nasa.gov/?v=-107366.71760836348,-806019.2028485272,1669789.9532940923,39981.42069566273&p=arctic&t=2020-11-17-T02%3A00%3A00Z&l=Coastlines,AMSRU2_Sea_Ice_Concentration_12km(max=30),VIIRS_NOAA20_Brightness_Temp_BandI5_Night(palette=rainbow_2,min=227.6,max=277.2,squash=true),VIIRS_SNPP_Brightness_Temp_BandI5_Day(hidden,palette=rainbow_2,min=227.6,max=277.2,squash=true),Reference_Labels(hidden),Reference_Features(hidden),VIIRS_NOAA20_CorrectedReflectance_TrueColor(hidden),VIIRS_SNPP_CorrectedReflectance_TrueColor(hidden),MODIS_Aqua_CorrectedReflectance_TrueColor(hidden),MODIS_Terra_CorrectedReflectance_TrueColor
Title: Re: The 2020/2021 freezing season
Post by: Pagophilus on November 17, 2020, 06:51:13 PM
19,5 °C positive anomaly yesterday on Golomyanny island

18,4°C positive anomaly on vize island
Thank you Positive retroaction.  Startling figures.  From my point of view, it would be great to know the absolute temperatures as well.

Yes, it's true
In golomany, yesterday had a minimum temperature of -3.5 ° C, an average temperature of -1.3 ° C and a maximum temperature of -0.9 ° C
On that day, November 17, the normal temperature was -21.5 ° C.

For the island of vize, the minimum temperature yesterday was -5.5 ° C
The average temperature was -0.3 ° C
The maximum 0.1 ° C
The normal average temperature is -18.7 ° C

More generally, anomalies between 9 and 11 degrees last for more than 1 month without stopping
Thank you!  Of note... the average air temperatures are above those at which sea ice typically forms...  Ocean surface temperature is paramount, of course.
Title: Re: The 2020/2021 freezing season
Post by: aslan on November 17, 2020, 07:32:22 PM
To be clear, because I am not sure I have state explicitly my point. I wanted to emphasize that an anomaly is not only stated by its absolute value. Deviation from normal is also a function of the normal spread. In winter in Arctic, an anomaly of 2-3°C is almost nothing while such an anomaly in the deep tropics could mean breaking a heat record. I did though that the heat could be more extreme than in 2016 for the Barents, but it was not fully the case. Heat is still extreme with some record (especially the 9.2°C reading of the Svalbard airport), but overall we are still within the boundary of the known climatology for this region in November. To the difference with August and September when anomalies expressed in absolute values were lower but were also way outside anything known.

P.S. : Or to put it more bluntly, in August and September, the red line was continuously way above the red dot at the top of the chart...
Title: Re: The 2020/2021 freezing season
Post by: Positive retroaction on November 17, 2020, 11:07:41 PM
To be clear, because I am not sure I have state explicitly my point. I wanted to emphasize that an anomaly is not only stated by its absolute value. Deviation from normal is also a function of the normal spread. In winter in Arctic, an anomaly of 2-3°C is almost nothing while such an anomaly in the deep tropics could mean breaking a heat record. I did though that the heat could be more extreme than in 2016 for the Barents, but it was not fully the case. Heat is still extreme with some record (especially the 9.2°C reading of the Svalbard airport), but overall we are still within the boundary of the known climatology for this region in November. To the difference with August and September when anomalies expressed in absolute values were lower but were also way outside anything known.

P.S. : Or to put it more bluntly, in August and September, the red line was continuously way above the red dot at the top of the chart...

Totally agree
We have just entered a period of the year when the variability is very high
Even if we are high in 2020, we stay in the known area, but permanently high
It is the continuity of the positive anomaly that concerns me
And its average magnitude, over the entire period, from July to now without stopping
In July, August and September, the variability is very low, but here we have flown above old records
Two months in a row of all-time highs and so far above variability is like a new climate state
I think if there is a tipping point in the arctic, kara will really be one of the seas that gives the imminent signs of this

I don t have the competence for this, but would anyone be interested in performing these things?
Lately I have seen that some people here are really good at representing reality on a graph, so that we can understand and see it.
So I put 2 links, where you will find all the weather reports in vize since 945-11-01
1950_2020-11-09
https://cdiac.ess-dive.lbl.gov/ftp/russia_daily/Russia_stations/20069.txt
The last 50 days
https://www.ogimet.com/cgi-bin/gsodres?lang=en&mode=0&state=Russ&ind=20069&ord=REV&ano=2020&mes=11&day=17&ndays=50
Maybe other links are better, sorry I m new for data treatment
But probably is profitable to put this realty on image, I wanted to do that since some weeks but I not succeed

I also post this
Average temperatures on August on vize Island
And average temperatures on September on vize Island

Data sources www.infoclimat.fr
Title: Re: The 2020/2021 freezing season
Post by: aslan on November 17, 2020, 11:25:02 PM
http://pogodaiklimat.ru/history/20069.htm

(and you just have to change the WMO id : 20046 for Heiss, 20087 for Golommjannyj, 21432 for Kotel'Nyj, 20292 for Mys Tchelouskine -the best one, longest record and craziest anomalies !, etc...)

Currently I am already working on two differents ideas (not directly related to Arctic sea ice...) so I don't have time to work out on the anomalies on the Russian islands. But for sure something is happening... Also, question mark is the method for computing monthly mean. Pogodaiklimat uses the mean of the height three hourly synoptic time (00Z, 03Z, etc...) to my knowledge. Which can change a bit the end result, as others sites can compute from the mean of Tx and Tn, or mean of six hourly synoptic time (?). There is also some errors, at least for Pogodaiklimat. For example, early datas for Golommjannyj. Should be worth a look. But in the end, yeah something get totally broken in August, and it is still ongoing.
Title: Re: The 2020/2021 freezing season
Post by: Positive retroaction on November 17, 2020, 11:30:08 PM
Thanks for reporting errors
I will try, I start with excel
Thank you
Title: Re: The 2020/2021 freezing season
Post by: Aluminium on November 18, 2020, 08:32:11 AM
November 12-17.

2019 (https://forum.arctic-sea-ice.net/index.php/topic,2888.msg237032.html#msg237032).
Title: Re: The 2020/2021 freezing season
Post by: Positive retroaction on November 18, 2020, 09:04:56 AM
what a retreat on the kara sea!
Title: Re: The 2020/2021 freezing season
Post by: jdallen on November 19, 2020, 07:03:13 AM
what a retreat on the kara sea!

I think we are going to see that as long as the hurricane season continue spawning storms.  After they break up, they still carry a huge amount of energy which consistently is being thrust north along the NAM eastern seaboard to blow into the Barents and Kara, with the last remnants being spun into the central basin proper.

This is the same rough pattern that first evolved in 2016 and has to a greater or lesser degree been continuing the last 4 years, and suggests a possible new weather regime.
Title: Re: The 2020/2021 freezing season
Post by: Freegrass on November 19, 2020, 07:17:28 AM
Latest Five Day Forecast + Last 24h
Wind + Temp @ Surface
Large GiF!

Where did the Arctic winter go? Did Santa Claus go in quarantine?
Title: Re: The 2020/2021 freezing season
Post by: Pagophilus on November 19, 2020, 01:52:44 PM
what a retreat on the kara sea!
I wonder how much of that dramatic retreat in the Kara was due to the newly formed ice being melted, and how much was simply crushed into a smaller area by the winds?  Either way, not good, but melting would be more alarming, IMO.
Title: Re: The 2020/2021 freezing season
Post by: BornFromTheVoid on November 19, 2020, 03:34:06 PM
The daily NSIDC extent remains 2nd lowest on record to the 18th, 594,000 km² above the lowest year, 2016. The last 5 days have seen substantial gains in Hudson Bay balanced by losses in the Kara sea, causing the centred 5 day mean increase to drop below average.
Title: Re: The 2020/2021 freezing season
Post by: gerontocrat on November 19, 2020, 03:48:15 PM
what a retreat on the kara sea!
I wonder how much of that dramatic retreat in the Kara was due to the newly formed ice being melted, and how much was simply crushed into a smaller area by the winds?  Either way, not good, but melting would be more alarming, IMO.
I don't know how much wind/waves and how much melt either, but it is a major reason why total Arctic sea ice extent and area daily gains have slowed down recently.
Title: Re: The 2020/2021 freezing season
Post by: Vince O on November 19, 2020, 11:45:43 PM
Is it just me or has the Pacific side / edge of the ice pack been retreating the last three days ?
Title: Re: The 2020/2021 freezing season
Post by: Darvince on November 20, 2020, 03:40:28 AM
Considering the current SST situation, I expect there to be an unusually long lasting polynya in the ice in the ESS until a record late date, perhaps mid-November or so.
Exactly November 15th is when ice growth filled in the last of the Laptev with ice extent. I guess the 1C-per-week after minimum rule of thumb I was using works very well for areas more secluded from storm activity and currents.

Extending it to other places, the Hudson should be fully frozen over between December 15th to 20th (although this might be sooner since it's so shallow in the areas that are at or above 2C right now), and the Okhotsk should start genuinely forming ice around December 5th.
Title: Re: The 2020/2021 freezing season
Post by: Pagophilus on November 20, 2020, 12:22:06 PM
Is it just me or has the Pacific side / edge of the ice pack been retreating the last three days ?
Eyeballing it, the answer for me would be 'yes, slightly'.  Worth watching..
Gerontocrat's replies #1876 and #1884 in the area and extent thread are worth reading in this context.
Title: Re: The 2020/2021 freezing season
Post by: El Cid on November 20, 2020, 02:04:25 PM
I still find 2018 the best analogue. We are cca 2 weeks behind:
Title: Re: The 2020/2021 freezing season
Post by: gerontocrat on November 20, 2020, 03:08:37 PM
Is it just me or has the Pacific side / edge of the ice pack been retreating the last three days ?
Eyeballing it, the answer for me would be 'yes, slightly'.  Worth watching..
Gerontocrat's replies #1876 and #1884 in the area and extent thread are worth reading in this context.
Chukchi sea ice extent and area down, just in the last 2 days.
Title: Re: The 2020/2021 freezing season
Post by: BornFromTheVoid on November 20, 2020, 03:59:03 PM
A week of NSIDC extent changes
Weekly change is +361,000 km² (81-10 avg: 456,000 km²)
Started 2nd lowest, finished 2nd lowest.
Largest gains in Hudson Bay followed by the Atlantic edge, mixed changes in Baffin and Chukchi Seas, and a large loss in the Kara Sea.

(Animated, click to play)
Title: Re: The 2020/2021 freezing season
Post by: Pagophilus on November 20, 2020, 07:10:32 PM
I still find 2018 the best analogue. We are cca 2 weeks behind:

Great illustration of where we are compared to another recent year.

An inexpert take on comparisons:  I think the 2016 refreezing season was so extraordinary that in some ways it has to be filed with the 2012 minimum as waaaay out there, the result of atypical conditions and therefore somewhat unsuitable for general comparisons.  In other words, the second-lowest extent for this year, both now and in September, is dramatic.  Focusing on first place (which I have to fight myself from doing) tends to conceal that.  Comparing the current state of the ice with the 'two weeks ahead' 2018 freezing season is much more revealing IMO.
Title: Re: The 2020/2021 freezing season
Post by: grixm on November 20, 2020, 07:34:37 PM
The ice is still quite thin in most of the siberian arctic.
Title: Re: The 2020/2021 freezing season
Post by: Glen Koehler on November 20, 2020, 10:08:34 PM
I still find 2018 the best analogue. We are cca 2 weeks behind:
(https://forum.arctic-sea-ice.net/index.php?action=dlattach;topic=3299.0;attach=292373;image)
      1.  That is a great comparison.  Does anybody have an estimate for how much thickness addition is lost for the April maximum by a two week delay in November freezing?

---------------------------------
      2. Late-September to mid-November 2020 DMI 80+N temperatures (first chart) continue to track almost as high as same dates in 2016 (second chart), and similar to but slightly warmer (eyeball estimate) than same dates in 2018 (third chart). 
     
      Will 2020 continue as warm until the end of the year as 2016, or follow the cooler (but still warmer than most years) track of late 2018? 
     
      The fourth chart of GFS 2M temperature anomaly forecast on Climate Reanalyzer suggests that 2020 high Arctic temperatures will continue well above the climatic average for the next 10 days.

      Despite the completely expected period of accelerated Extent and Area gains after the delayed start, late 2020 so far is not providing much indication for a robust compensatory refreeze after the low September minimums.  Refreeze season is just barely over 50% done, so too early to estimate, but from what we have seen so far it is looking like ASI could enter the 2021 melt season in an unusually vulnerable condition from the surface-and-above view.
Title: Re: The 2020/2021 freezing season
Post by: Glen Koehler on November 21, 2020, 01:42:57 AM
       Then I look at Polyakov et al. 2020 and start to wonder if all this attention to top-side forcings overlooks the near-surface turbulence with vertical mixing and below-surface halocline/thermocline & heat diffusion transformation that could be where the major forcing is taking place.  It's too bad we don't have equivalent graphical products for tracking and prediction of "ocean weather" (e.g. water temperature, salinity plumes, movement of water masses analogous to air masses, etc.).  Those measures are available, but their presentation is not as highly developed or as routinely presented for layperson consumption as the atmospheric weather products we are used to. 

       My growing suspicion is that like a drunk looking for his keys under the street light, we are focusing our attention where it is easiest to see what's going on.  But to understand the real situation we need to look at a broader range of monitoring tools.  It is often said that the Arctic provides never-ending surprises.  Perhaps our above-surface bias is a contributing factor to our being regularly surprised (says the guy who just posted 4 air temperature charts).

       A-Team, uniquorn and others are posting stuff about the water world perspective.  Much of it is not as easy to summarize for the lay reader (like me) to intuitively understand.  A chart showing a big red blob marking a positive aerial temperature anomaly over the Arctic is easy to understand.  Similar synoptic standardized graphs for the surface and sub-surface water measures would be a useful addition.  Easy for me to say because I'm not going to be the one to do anything about it. 

      I'm just pointing out that 71% of the Earth's surface that interacts with greenhouse gas heat-trapping insulation is water.  That 93% of the added heat energy from global warming is in the water.  That H2O vapor is a stronger greenhouse gas than CO2.  And now, with respect to the ASI, Polyakov and others are quantifying what should have been obvious all along (and probably was to those who study this stuff) that those of us watching the ASI drama need to pay more attention to the water that the ice is floating in and made from if we want to understand what is going on.
Title: Re: The 2020/2021 freezing season
Post by: Aluminium on November 21, 2020, 07:58:17 AM
November 15-20.

2019 (https://forum.arctic-sea-ice.net/index.php/topic,2888.msg237881.html#msg237881).
Title: Re: The 2020/2021 freezing season
Post by: oren on November 21, 2020, 08:24:49 AM
The CAB is clawing its way again to FJL. Meanwhile in the southern Kara a massive retreat. Did that ice actually melt or was it squeezed in somehow?
Title: Re: The 2020/2021 freezing season
Post by: BornFromTheVoid on November 21, 2020, 12:58:41 PM
Here's the slow sea ice concentration animation for the last week.

Regionally, big gains in Hudson Bay and along the Atlantic edge, mixed changes in Baffin, slight losses in Chukchi and big losses in the Kara Sea.
Title: Re: The 2020/2021 freezing season
Post by: BornFromTheVoid on November 21, 2020, 01:07:37 PM
The CAB is clawing its way again to FJL. Meanwhile in the southern Kara a massive retreat. Did that ice actually melt or was it squeezed in somehow?

Looks like both. Southwesterly wind and temps a little above freezing for most of the last week.
Title: Re: The 2020/2021 freezing season
Post by: Vince O on November 22, 2020, 11:50:17 AM
Well it looks like the ice is going to get a double whammy on both sides of the pack in the next week. According to the forecast on both Climate Reanalyzer and Earth nullschool the Pacific side which is already suffering a melt / push back (I'm being honest, I don't know why) will be getting sustained 50-60 km/h winds in exactly the direction it doesn't want along the Chuckchi and East Siberian Seas coast line. Sure that will push the ice back considerably.
     Then we have ther forecast on the Atlantic side for next Friday / Saturday (Yes, I know it's past four days, just) which, looking at both C.ReA and Earth Nulls conferring with each other the approach. I know things change, esp this year but it does look quite aweful hitting again where the ice is thin and only just getting itself reconsolidated after the last storm. This one looks bigger, deeper through the Fram Straight again. Can only watch tomorrow and Tuesday to see what might happen but with both forecasts having the storm come up Greenlands coast on Thurday late evening it doesn't look good.
Title: Re: The 2020/2021 freezing season
Post by: Pagophilus on November 22, 2020, 07:09:25 PM
Here's the slow sea ice concentration animation for the last week.

Regionally, big gains in Hudson Bay and along the Atlantic edge, mixed changes in Baffin, slight losses in Chukchi and big losses in the Kara Sea.

Also interesting (and probably worrying):  the new ice pack temporarily detaching from almost the entire Laptev coast and from some islands in the Laptev Sea on your animation BFTV.   Probably caused by SSW winds? -- the same winds you mention in your reply to oren above?  This sure looks like ice motion rather than ice melting.
 
Thanks as ever for these superb animations.
Title: Re: The 2020/2021 freezing season
Post by: uniquorn on November 23, 2020, 12:23:12 PM
Not only the Laptev. The Alaskan coast in the Beaufort is also looking unsettled. Southerly winds, then persistent easterlies drawing ice out to sea. (ice to the right of wind) Possible there is also upwelling there.
http://bulletin.mercator-ocean.fr/en/permalink/PSY4/animation/3/20201101/20201123/2/2

amsr2 awi v103, nov14-22
the swaths on this dev version not quite overlapping on nov15

The low concentration area verifies on viirs brightness temperature https://go.nasa.gov/3pTbTsN
Nullschool has ~-16C there today so the leads will be refreezing except those close to the chukchi.

edit: added laptev while it's all set up
Title: Re: The 2020/2021 freezing season
Post by: Aluminium on November 25, 2020, 05:46:04 AM
November 18-24.

2019 (https://forum.arctic-sea-ice.net/index.php/topic,2888.msg238318.html#msg238318).
Title: Re: The 2020/2021 freezing season
Post by: Pagophilus on November 25, 2020, 04:40:44 PM
Some general context via NOAA on where the Earth has been anomalously warmest this year through Oct 31.  And how hot the Northern Hemisphere has been during this period.  My bolding.

"The global land-only January–October 2020 temperature departure of +1.60°C (+2.88°F) tied with 2016 as the highest temperature for January–October on record. The global ocean-only surface temperature was the second highest on record, behind the record set in 2016. The Northern Hemisphere land and ocean surface temperature was 1.29°C (2.32°F) above average and the highest on record for the January–October period , exceeding the previous record set in 2019 by 0.02°C (0.04°F). "

https://www.ncdc.noaa.gov/sotc/global/202010

Central Siberia is obvious.  The cold blob in the North Atlantic is still going strong.
Title: Re: The 2020/2021 freezing season
Post by: grixm on November 26, 2020, 02:28:41 PM
Just a tip guys, if you're like me and check cryospherecomputing.tk regularly, but noticed that it has been down for the last few days, then the old site hosted by google but containing most of the same charts, is still up:

https://sites.google.com/site/cryospherecomputing/daily-data
Title: Re: The 2020/2021 freezing season
Post by: bbr2315 on November 27, 2020, 03:55:45 PM
As I suspected would occur, Hudson's refreeze was very rapid and is now almost complete. Ahead of any year since 1995, it seems per El Cid's data. I think this will aid in advection of Atlantic oceanic heat into the Barents / Kara / Laptev / CAB and we have now made up a big chunk of the "easy" gains as well. The fact we lost ice yesterday (while Hudson is still making its last leaps forward) is a very bad sign for the actual Arctic Basin, IMO.
Title: Re: The 2020/2021 freezing season
Post by: BornFromTheVoid on November 27, 2020, 04:00:46 PM
Russian Arctic sea's have flatlined in the last 10 days and are back below 2012. Without a significant acceleration in growth, 2020 will be back to the lowest values in a week.
Title: Re: The 2020/2021 freezing season
Post by: Vince O on November 27, 2020, 07:19:25 PM
So looks like consistent 60-70km/hr winds driving out of the Fram Starit to the Atlantic for just over 24 hrs and a storm just North with 60 km/hr winds blowing into the pack. Does anyone think there might be any disruption of the ice on the Greenland North-East peninsula ? Maybe the winds this strong for a 24hr period might have some effect ?
Title: Re: The 2020/2021 freezing season
Post by: oren on November 27, 2020, 10:22:45 PM
As I suspected would occur, Hudson's refreeze was very rapid and is now almost complete. Ahead of any year since 1995, it seems per El Cid's data. I think this will aid in advection of Atlantic oceanic heat into the Barents / Kara / Laptev / CAB and we have now made up a big chunk of the "easy" gains as well. The fact we lost ice yesterday (while Hudson is still making its last leaps forward) is a very bad sign for the actual Arctic Basin, IMO.
Indeed, you predicted fast Hudson Bay growth which materialized, as also shown by the AMSR2 area data.
As El Cid notes, 2018 is still ahead of 2020 by a bit, though this might change in a few days. In addition, 2014 is not far behind.
Title: Re: The 2020/2021 freezing season
Post by: uniquorn on November 27, 2020, 10:40:18 PM
amsr2 awi v103 hudson, nov1-27(early) click for animation
noaa sea ice concentration, hudson nov27, 1981-2019 animation and compressed static (might be useful for the atmospheric connections thread) No data for 82 and 85.
The static image is compressed 1/10 width for easier visual comparison see more detail for other areas on the mosaic thread here (https://forum.arctic-sea-ice.net/index.php/topic,2906.msg294036.html#msg294036)
amap hudson bay currents.
Title: Re: The 2020/2021 freezing season
Post by: uniquorn on November 28, 2020, 01:13:27 PM
cs2smos merged sea ice thickness, oct22-nov25. The thicker short wrangel arm area north of ESS appears to have dispersed. smos also picking up the lower concentration area north west of Mackenzie Bay (see post #855 up thread)
click for animation

Reasonably cloudless over the Beaufort since nov21   https://go.nasa.gov/37hZwxQ
Title: Re: The 2020/2021 freezing season
Post by: oren on November 30, 2020, 01:29:57 PM
While 2020 is currently 2nd lowest in extent, behind 2016, this is due to 2016's very delayed Hudson Bay refreeze. Within the Arctic Basin 2020 extent is now back to lowest on record according to all 3 measures tracked by Wipneus - UH, JAXA and NSIDC.
Click to enlarge.

(https://sites.google.com/site/arctischepinguin/home/amsr2/grf/basin-extent-multiprod.png)
Title: Re: The 2020/2021 freezing season
Post by: gerontocrat on November 30, 2020, 02:03:13 PM
While 2020 is currently 2nd lowest in extent, behind 2016, this is due to 2016's very delayed Hudson Bay refreeze.......
.... and 2020's very advanced refreeze giving Hudson Bay sea ice area and extent above the 1990s average.....
and Greenland sea ice extent and area approaching the 1990's average.
Title: Re: The 2020/2021 freezing season
Post by: BornFromTheVoid on November 30, 2020, 03:20:38 PM
Here's an animation highlighting the waxing and waning of the Kara sea ice coverage so far this refreeze.
Click to play
Title: Re: The 2020/2021 freezing season
Post by: Pagophilus on November 30, 2020, 04:05:25 PM
While 2020 is currently 2nd lowest in extent, behind 2016, this is due to 2016's very delayed Hudson Bay refreeze. Within the Arctic Basin 2020 extent is now back to lowest on record according to all 3 measures tracked by Wipneus - UH, JAXA and NSIDC.
Thank you.  I was wondering about this.   And thanks gerontocrat and BFTV.   A question:  The Canadian side has been cooler this year and we all know about Siberia's toastiness.  So might an expectation be that Kara, Chukchi and Okhotsk will refreeze slowly and 2020 extent will have as wild a refreeze ride as 2016 did?  Or is that a low probability?
Title: Re: The 2020/2021 freezing season
Post by: El Cid on November 30, 2020, 04:47:37 PM
.... and 2020's very advanced refreeze giving Hudson Bay sea ice area and extent above the 1990s average.....
and Greenland sea ice extent and area approaching the 1990's average.

Oh yes! We seem to have a forming new Cold Pole in the Greenland-Hudson area. It seems to be a trend since 2014 when the Chukchi started to be more open very late (results in warm Chukchi, warm Eurasia, cold NA, esp. Canada)...Talked about that in the atmospheric connections thread. This is 2014-20 winter temps vs 2006-13:
Title: Re: The 2020/2021 freezing season
Post by: bbr2315 on November 30, 2020, 06:31:38 PM
.... and 2020's very advanced refreeze giving Hudson Bay sea ice area and extent above the 1990s average.....
and Greenland sea ice extent and area approaching the 1990's average.

Oh yes! We seem to have a forming new Cold Pole in the Greenland-Hudson area. It seems to be a trend since 2014 when the Chukchi started to be more open very late (results in warm Chukchi, warm Eurasia, cold NA, esp. Canada)...Talked about that in the atmospheric connections thread. This is 2014-20 winter temps vs 2006-13:
It is quite interesting that the rise of the Hudson-Greenland "cold pole" is also coinciding with substantial cooling of Saharan Africa. We may have the mechanism for "green Sahara" unfolding before our eyes. The collapse of a stable three-cell system is likely to have both negatives and positives, and I would assert that we may be witnessing one such positive (i.e., colder and wetter conditions in Northern Africa) now rapidly unfolding on an inter-annual basis.
Title: Re: The 2020/2021 freezing season
Post by: gerontocrat on November 30, 2020, 09:30:35 PM
I have a feeling that this year's freezing season might be the season of unpredicatability writ large.

We had the enormous extent rebound in late Oct early Nov.
Since then in most places refreeze is slow, with sea ice losses on occasion in the Central Arctic and the Kara..
We've had a late Hudson Bay refreeze start immediately followed by massive extent gains.
Greenland sea ice extent is really high.
NSIDC High Arctic sea ice extent lowest in the satellite record, but sea ice area in the peripheral seas only 6th lowest.
La Nina is supposed to favour a really cold Canada.

All this looking more and more like a WACC scenario, with cold very much on the Greenland and Canada land masses.

But then this Thursday looks really different over much of Canada, and later on Greenland may be warming up somewhat.
Title: Re: The 2020/2021 freezing season
Post by: binntho on December 01, 2020, 04:26:16 AM
It is quite interesting that the rise of the Hudson-Greenland "cold pole" is also coinciding with substantial cooling of Saharan Africa.

Seeing as how I live there, I always check the anomaly maps to see how Sub-Saharan Africa is doing. And I have yet to see any anomaly map showing "substantial cooling" of Saharan Africa. I've not seen any maps showing any cooling of Saharan Africa. But perhaps you have? Please share.

EDIT: El Cid's post abov (https://forum.arctic-sea-ice.net/index.php/topic,3299.msg294548.html#msg294548)e does show a cold blob over south-central Sahara. So request for sharing withdrawn. But as Oren points out, this could be an intersting discussion held elsewhere.
Title: Re: The 2020/2021 freezing season
Post by: oren on December 01, 2020, 04:36:11 AM
Please share but not in this thread. The Sahara should be discussed elsewhere.
Title: Re: The 2020/2021 freezing season
Post by: gerontocrat on December 01, 2020, 03:25:10 PM
Here are a couple of forecasts from Environment Canada.
December - https://weather.gc.ca/saisons/image_e.html?img=mfe1t_s
Jan- March 2021 https://weather.gc.ca/saisons/index_e.html

& From Russia
Russia - Jan-March -  https://meteoinfo.ru/en/climate/seasonal-forecasts ****

The December forecast is for above average temperature, apart from a cold blob in Hudson Bay
The 3 month forecast for Jan-Mar 21 looks a lot colder especially in Northern / Central Canada- look at the really really cold blob in Hudson Bay.

But the Russian forecast is for above averge temps in early 2021 for Siberia.

Warmish December and horribly cold early 2021?


Title: Re: The 2020/2021 freezing season
Post by: El Cid on December 01, 2020, 04:29:56 PM
I am not sure these seasonal forecasts are good for anything. As far as I remember their chance of coming true is not better than rolling a dice. 

I think looking at the average of the past years is at least as good as these:

Title: Re: The 2020/2021 freezing season
Post by: oren on December 01, 2020, 05:45:33 PM
AMSR2 area updates (using UH data by Wipneus):
* The Chukchi is slow going, though not at record territory with 2017 and 2019 bottom-leading.
* The Bering and Okhotsk are still asleep, a common behavior on this date but definitely not first our of the gate. If Bering doesn't wake up it could be at record  AMSR2 low in a week.
* Hudson Bay is quite ahead but despite expectations is still within the herd, with 2014 and 2018 top-leading.
* The Kara appears to be going in reverse, and is at record low territory (for AMSR2 data). Have we seen the freezing season maximum?  :o (Just kidding of course).

Click to enlarge.
Title: Re: The 2020/2021 freezing season
Post by: gerontocrat on December 01, 2020, 06:23:02 PM
I am not sure these seasonal forecasts are good for anything. As far as I remember their chance of coming true is not better than rolling a dice. 

I think looking at the average of the past years is at least as good as these:
If you are right about that, that's an awful lot of highly skilled time, ginormous computer power and money being thrown down the gurgler.

The Russians got it right about Siberia last year - but then again even The Farmer's Almanac gets it right sometimes.
Title: Re: The 2020/2021 freezing season
Post by: El Cid on December 01, 2020, 08:24:27 PM
I am not sure these seasonal forecasts are good for anything....
If you are right about that, that's an awful lot of highly skilled time...wasted...

I think I am right about this, though someone with more knowledge might refute me. I won't post more of it here, because it is somewhat OT here (though as many use these seasonal forecasts, maybe not so much).

Anyway, first pic is the skill of a simple persistence model (if you have an anomaly, you expect that to stay for the next month), second is ECMWF seasonal forecast skill (detrended!). Paper is from 2010. There is basically no forecasting skill in the detrended version. There is some skill in the normal (non detrended) version but that is mostly due to global warming: you need to expect warmer than average temperatures and you will be right most of the time. But that is no skill...

(Doblas-Reyes: seasonal prediction over europe)