The 2020/2021 freezing season

[gerontocrat]

NSIDC Data from WIPNEUS- Sea Ice Area Graphs of the 2020-21 Freezing Season for each sea - continued

In this post...just because you have probably never seen it before..

The Baltic Sea sea ice Extent and Area graphs.

[Stephan]

some ice in the Baltic Sea in June 2020??? Never!
(probably the old problem with close to shore regions)

[oren]

Yeah it's obvious a lot has to do with NSIDC noise and with the monthly masks. But still there doesn't seem to be a trend since the 90s.

[Killian]

Following three days of extent losses, concentrated in "real" seas such as Bering, Barents and the Greenland Sea, rather than the marginally attached Okhotsk, and considering the relatively late date, we are now officially switching over to the 2021 melting season. Fasten your seat belts!

This post *might not* age well. Just 120k short of the peak and the AO going strongly positive... again. If the melt season is half as whacky as the end of the freeze, well...

[Freegrass]

Latest Five Day Forecast
Wind + Temp @ Surface
Very Large GiF!

I've created this forecast with a larger overview so it includes the peripheral seas. That way it's easier to determine if we have reached the melting season yet. And we sure are close!

I think we'll be there in 2 or 3 days from now.
I think tomorrow is a good day to open the melting season thread.

I love to see the planet's "heartbeat" creeping back up again...

I'm so angry at myself right now... I should have stuck to my initial thought, and waited for a few more days... 

[Niall Dollard]

Juan reporting today that Jaxa extent is now within 93K of the March 10th max.

Classic end of season wobbles.

[Killian]

Juan reporting today that Jaxa extent is now within 93K of the March 10th max.

Classic end of season wobbles.

And with the circumpolar winds about to tighten up significantly again. It's pointless ice formation that will mean nothing to the melt season being so new and thin, but if it sets a new extent record, I'm going to be angry with myself for assuming the lateness of the date should outweigh the physics of the AO.

[The Walrus]

The freezing season refuses to end.  NSIDC set a new maximum extent yesterday.

[gerontocrat]

The freezing season refuses to end.  NSIDC set a new maximum extent yesterday.

That was for the 5 day trailing average extent .
The one day extent measure is still not a new maximum - by 78k, though it increased by 25k to 14.788 million km2.

In 2015 NSIDC one day extent max was on the 23rd March, but the 5-day area max was on the 13th March

In 2010 the JAXA extent max was on 31 March.

March is the wobbly month

[Freegrass]

The freezing season refuses to end.  NSIDC set a new maximum extent yesterday.

Moral of the story for me is that when extend is low. there's more potential for extra growth later on in March, as the ice edge is in regions that should have a lot more ice left this time of year.

[The Walrus]

The freezing season refuses to end.  NSIDC set a new maximum extent yesterday.

Moral of the story for me is that when extend is low. there's more potential for extra growth later on in March, as the ice edge is in regions that should have a lot more ice left this time of year.

Agreed.  Based on NSIDC data, for every million square kilometer decrease in the Arctic sea ice minimum extent, the ice gain through the winter solstice increases by 55%.

[gerontocrat]

As far as the 7 central seas of the High Arctic are concerned - it ain't over 'til it's over.

From NSIDC Data we find that in the last 3 days sea ice area of the High Arctic has increased by 57k to 8.688 million km2, some 44k above the previous maximum of 8.644 million km2 on the 17th February. So on the 29th March sea ice area is 35th lowest, 9th highest, in the satellite record.

Average daily sea ice area change from now would give a maximum of 8.708 million km2 on the 9th April.

High Arctic sea ice extent hasn't quite got there, still 2k below the current maximum of the 19th March

[Jim Hunt]

As far as the 7 central seas of the High Arctic are concerned

Do you include the Kara in your "High Arctic"?

[gerontocrat]

As far as the 7 central seas of the High Arctic are concerned

Do you include the Kara in your "High Arctic"?

Central Arctic, CAA, Beaufort, Chukchi, ESS, Laptev, Kara.
It is consistent with the AWP analyses of Tealight aka Nico Sun.

They are in the Arctic Ocean, and bounded by land or at least in winter by sea ice, although with the Barents gradually and erratically becoming totally Atlantified, this is no longer a certainty as regards the Kara.

[Jim Hunt]

This is no longer a certainty as regards the Kara.

Which is no doubt why Wipneus didn't include the Kara in his definition of "The Arctic Basin". Hence:

[oren]

If I am not mistaken Wipneus also excludes the CAA from his definition of the "Basin".
For ice statistics I personally prefer Gero's High Arctic, at least given current conditions. When Kara becomes the new Barents it will be time to update the boundaries.

[Jim Hunt]

If I am not mistaken Wipneus also excludes the CAA from his definition of the "Basin".

That is true. However just to be different I added the CAA to my definition displayed above!

The Kara already looks a lot like the Barents, in summer at least. I suppose it depends on whether ones inclusion/exclusion criterion is "mostly full in winter" or "mostly empty in summer"?

[gerontocrat]

The High Arctic as defined by Nico (and myself) is obviously far more than the Central Arctic basin

To me the High Arctic is essentially the Arctic Ocean, once you accept that the Ocean is bounded by the Russian and North American mainland and that the Barents is more a part of the North Atlantic Ocean than the Arctic ocean.

I am not sure that even when the Kara winter ice collapses the sea should be excluded, as the Kara is in the Arctic Ocean and its transformation from an icy desert to an open water sea that sometimes has some ice in it is just part of the long-term change to a largely ice-free Arctic Ocean (when people will start to talk about all of it to be renamed as part of the Atlantic Ocean?)

That's my story and I am sticking to it.

[Tealight]

I defined the High Arctic for my AWP model. This heatmap should make it clear why the Barents Sea is excluded and Kara is included.



AWP in percent of Icefree conditions

[gerontocrat]

I defined the High Arctic for my AWP model. This heatmap should make it clear why the Barents Sea is excluded and Kara is included.

That'll do nicely for me.

[Jim Hunt]

I defined the High Arctic for my AWP model.

Thanks for the detailed explanation Nico. Now I know why my "Arctic Basin" graphs look different to gero's "High Arctic".

IIRC the reason Wipneus excluded Kara from his version of the "High Arctic" was that the region contributed very little to the minimum extent in September.

Your heat map confirms that over the last decade or so the Kara looks more and more like Hudson Bay rather than the Laptev Sea.