The 2020/2021 freezing season

[Freegrass]

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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.

[oren]

Please continue posting in the melting season thread for a couple of days.

[be cause]

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.

[Shared Humanity]

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.

[gandul]

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.

[Gumbercules]

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).

[I’M IN LOVE WITH A RAGER]

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

[jens]

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.

[El Cid]

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

[gandul]

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.

[oren]

The 2020/2021 freezing season has officially begun.

[Freegrass]

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... 

[Freegrass]

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[Shared Humanity]

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.

[BornFromTheVoid]

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!

[anaphylaxia]

Wow, excellent representation of the whole season!

[Wildcatter]

I know one thing, a winter season like last year with a strong polar vortex low-pressure dominated, would not be ideal.

[gandul]

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:

[nanning]

Bravo Samuel, beautiful. Thanks for all your efforts!
What ana says.

[Freegrass]

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?

[jai mitchell]

I truly thought we would beat the 2012 minimum this year due to a massive decrease in global aerosol loading.  But we didn't.

[Freegrass]

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!

[I’M IN LOVE WITH A RAGER]

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.

[Pavel]

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

[gandul]

The green and blue regions in this map imo will refreeze fast.

[be cause]

.. 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 .

[jdallen]

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.

[Positive retroaction]

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
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

[BornFromTheVoid]

Today's images and animation. The gains in the Beaufort Sea have persisted, so more evidence that the minimum has been passed.

[Paladiea]

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

[Freegrass]

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Notorious Ravaging Big Gale

[Pagophilus]

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.

[Pagophilus]

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?

[BornFromTheVoid]

Animation of the annual max and min, from 1979 to present (click to play).

[Stephan]

Very nice animation. Thanks for all these great contributions. 

[D-Penguin]

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.

[VeliAlbertKallio]

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).

[Aluminium]

September 14-19.

2019.

[BornFromTheVoid]

Latest images and animation. Ice gained in the Beaufort Sea over the previous two days has mostly disappeared now.
Will it return?

[Freegrass]

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[BornFromTheVoid]

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.

[Niall Dollard]

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.

[be cause]

https://go.nasa.gov/3mDgI7M .. gateway to a winter wonderland .. I hope . Today at the North pole . b.c.

[The Walrus]

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.

[Pagophilus]

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.

[oren]

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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.

[BornFromTheVoid]

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.

[BornFromTheVoid]

Today's images and animation.

[Freegrass]

Latest Five Day Forecast
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[Freegrass]

Latest Five Day Forecast
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Large GiF!

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...