The 2020/2021 freezing season

[Neven]

Please, don't sh*t on NSIDC and in the same comment mention HYCOM as an example of how it should be done. HYCOM is extremely unreliable, and there is hardly any documentation that explains what they are changing when, what and how (and they don't have to, because they are not a scientific institute).

It is very important to be consistent if you want to have a long-term record, and what the NSIDC is doing, is perfectly logical. If you don't see that logic, then maybe you have some more learning to do.

Nevertheless, it would be perfectly fine to start a new long-term record, but I haven't looked into what is going on with satellites to know whether that is an option. And we also don't need perfect data and satellite imagery to see where things are headed in the Arctic.

[oren]

A. What Neven said.
B. FG if you want to discuss satellite and data policies further then fine, but not on this thread.

[Jim Hunt]

They always have the option to post the consistently wrong data, and the new corrected one side by side...

Please desist. I've already pointed you in this direction, but to save you the bother of doing your own research see this "consistently wrong data" from the NSIDC:

https://nsidc.org/data/masie/masie_plots

Item 1 from the FAQ:

The Sea Ice Index (SII) relies on satellite passive microwave data as its only data source. These data are automatically processed using an algorithm and have known biases and limitations; these are covered in the SII documentation. MASIE relies on data from the Interactive Multisensor Snow and Ice Mapping System (IMS) that runs at the U.S. National Ice Center (USNIC). The IMS product uses several satellite data sources including passive microwave, but it is also based on visual analysis and other data sources and undergoes a form of manual data fusion. Another difference is in the resolution of the products. The MASIE product has a nominal 4-km resolution which is higher than the nominal 25-km resolution of the SII.

[Killian]

Unless there is some rebound (or an additional crash), we will change over to a melting season thread on March 1st.

March 1 might be a bit early.

Given the predicted AO, and that we only need +50k for five days, I can pretty easily see a new peak well into March. Put another way, less than 18k/day till March 12 would give us a new peak. Then, again, the AO is supposedly headed to neutral over the next days.

[interstitial]

And then people ask me why I call them Americannots?

1st this is an offensive statement and does not strengthen your position. I can just as easily make vague offensive statements about you. Americans are flawed but your sh*t stinks too. Please wait before you post when you are worked up about something.
There is a relatively small community of people globally who work in this field. The satellite assets are shared. While individuals and institutes claim credit for certain products the connections between resources and individuals show that no country is really doing this work independently. It is not a position tied to nationalism.

Please, don't sh*t on NSIDC and in the same comment mention HYCOM as an example of how it should be done. HYCOM is extremely unreliable, and there is hardly any documentation that explains what they are changing when, what and how (and they don't have to, because they are not a scientific institute).

Neven I believe you have a strong bias against HYCOM which I do not understand is it because of it is associated with the US military or some other reason?
NSIDC produces many different ice products for different purposes. They produce an algorithm based product for long term consistency for climate work. They also make a more accurate product which uses human judgement for current conditions. This is the part that invalidates it for long term climate comparisons. HYCOM uses the current conditions product as a starting point. Most of the world shares these satellite resources and the community of people in the field does not appear to be that big.
HYCOM data is reliable. They fully document all changes they make. Further before each change is made they must validate that the change improves the model before the model is changed. All of this is available online if you wish to look though most if it is available at the civilian sight. Only the data is available at the military sight.
I agree this is more of a side topic but once inflammatory comments are made in the main thread some response in the main thread is appropriate.
 

[Stephan]

An increase lowers the threshold value to 0.25 ± 0.01 M km². Therefore some years move one bin to the left:

                     A       B       C
1979-1989:    3       0       8
1990-1999:    1       1       8
2000-2009:    1       1       8
2010-2020:    5       0       6       (2010, 2012, 2014, 2019 and 2020 result in "A")
sum:            10       2     30

[Jim Hunt]

An increase lowers the threshold value to 0.25 ± 0.01 M km².

The "rebound" has begun! Hence I've added the curve for 2006 to the increasingly crowded JAXA summary:

https://GreatWhiteCon.info/2021/02/the-2021-maximum-arctic-sea-ice-extent/#Feb-26

[Jim Hunt]

HYCOM data is reliable. They fully document all changes they make.

Maybe so, but since we're still in the (soon to be redundant?) freezing season thread for now, GOFS "modelled" thickness doesn't currently look a whole lot like CS2/SMOS "measured" thickness?

[Freegrass]

It looks like NSIDC data is back to normal.

[Iain]

And similar to the profile from Jaxa.

[Iain]

But differs from Chartic, which this morning still shows the nosedive. Looks like processing the data for Chartic is the problem, not the satellite data itself:

"Sea ice processing is currently having problems. Daily Sea Ice Index/Arctic Sea Ice News and Analysis values after February 19 are erroneous. NSIDC is investigating the issue and will correct it as soon as possible."
https://nsidc.org/arcticseaicenews/

[psymmo7]

Thank you for your wise moderation Interstitial.

[gerontocrat]

It looks like NSIDC data is back to normal.

I think the graph only shows 2021 data to about the 20th Feb.

[Iain]

^  Caption says 23 Feb. I would expect the most current (as of Sat AM) would normally be the 25th

[oren]

Folks, please avoid personal comments and snark (or responding to such). I have been lax due to being RL busy, but I will remove/edit/move as needed if things escalate.

[gerontocrat]

^  Caption says 23 Feb. I would expect the most current (as of Sat AM) would normally be the 25th

I think the NSIDC data is in quite a bit of trouble.

This is an excerpt from the data of NSIDC one-day extent sheet from the latest file (26 Feb 14:34 Colorado time)

Mth   day   2019       2020       2021

Feb   18   14.553   14.643   14.294
Feb   19   14.596   14.669   14.329
Feb   20   14.678   14.753   
Feb   21   14.709   14.857   13.154
Feb   22   14.708   15.000   
Feb   23   14.699   14.836   
Feb   24   14.652   14.749   
Feb   25   14.573   14.723   
Feb   26   14.611   14.774   

And from the 5 day extent sheet on the same file
Mth   day   2019        2020       2021

Feb   17   14.462   14.667   14.508
Feb   18   14.479   14.689   14.467
Feb   19   14.495   14.677   14.436
Feb   20   14.547   14.692   14.266
Feb   21   14.599   14.719   13.984
Feb   22   14.649   14.784   13.734
Feb   23   14.678   14.823   13.595
Feb   24   14.689   14.839   13.35
Feb   25   14.668   14.833   13.154
Feb   26   14.649   14.816   
   
Methinks the thing to do is to wait until NSIDC says all is OK - (usually posted on https://nsidc.org/arcticseaicenews/ )

[echoughton]

Great to be back with ya'll. Noticed the nose dive and thought...WTF! I see from posts that it is wrong. Extent still moving up...but wobbling? Is the extent in any way better than recent years. I did notice it's ahead of 16, 17 and 18 but volume? Trend still downward I am sure.

[oren]

Hello echoughton, you can read all about it in the area and extent data thread and in the PIOMAS volume thread. Extent was higher than most recent years but recently dropped to 2nd or 3rd lowest while wobbling. Volume is 3rd lowest after 2017 and 2018, interestingly both years had a weaker melting season than other years with higher winter volume and extent such as 2012, 2019 and 2020.

[Thomas Barlow]

http://polarportal.dk/en/sea-ice-and-icebergs/sea-ice-extent0/#c8091

Not much to quote in your post Thomas!

FYI:

Can you make an explanation and somewhat valid correlation, between air temps and sea surface temps over the last few weeks to that sudden drop?
Thanks in advance.

The sensors are probably blown, old, and malfunctioning. Technicians stuck at home, trying to do remote work, short-staffed, fractures in the system that was barely functional before 2020, due to cutbacks, career-instabitlities, back-biting, and disintegration of coherent science in every field now.

Or, maybe not?

[Thomas Barlow]

And then people ask me why I call them Americannots?

Neven I believe you have a strong bias against HYCOM which I do not understand is it because of it is associated with the US military or some other reason?
NSIDC produces many different ice products for different purposes. They produce an algorithm based product for long term consistency for climate work. They also make a more accurate product which uses human judgement for current conditions. This is the part that invalidates it for long term climate comparisons. HYCOM uses the current conditions product as a starting point. Most of the world shares these satellite resources and the community of people in the field does not appear to be that big.
HYCOM data is reliable. They fully document all changes they make. Further before each change is made they must validate that the change improves the model before the model is changed. All of this is available online if you wish to look though most if it is available at the civilian sight. Only the data is available at the military sight.
I agree this is more of a side topic but once inflammatory comments are made in the main thread some response in the main thread is appropriate.

HYCOM is mostly navy isn't it?
And as I've said on here for years, navy only really cares about what spaces they can push a boat through

[Thomas Barlow]

http://nsidc.org/arcticseaicenews/

[Thomas Barlow]

Has ArctischePinguin retired?

https://14adebb0-a-62cb3a1a-s-sites.googlegroups.com/site/arctischepinguin/home/amsr2/grf/basin-area-multiprod.png?attachauth=ANoY7cpFmtXPf3ZDZcKDIvdcVPFFcPtwHe8E6pfAsULA9nuDGthevCuEfJ_ABt29oVH_dN6M1bV6ohF1N41jT9vwvv17XnHb8u_SOE68KzBG3iRWLhyH2yHejL8HVIHrnHxWUvVBJTWepdHgIFr_FN2maNvOuHsV3J1EEtjUiMvEEsT1T4zF2-3EpRHkCG9iA_YyDdHrHoeg4pWQsKGiOkyKEOS0JSRfrNqczSR4A4sY1EZDWISAV1Y-gccshOnvE4y_dw7e7lWP&attredirects=0

[kassy]

Five replies in a row is a bit much. 1270 and 1271 are on last page or the other thread recently so no need to repeat them and 1269 while true can probably be skipped too.

[Jim Hunt]

Or, maybe not?

Not:

https://forum.arctic-sea-ice.net/index.php/topic,3299.msg301361.html#msg301361

[oren]

Has ArctischePinguin retired?

No, but Wipneus usually take s a while to switch over the new year in his charts. I have the same issue myself in my volume charts.

And please don't post so many consecutive posts, some of which have been posted upthread already.

[Jim Hunt]

Perhaps it's still somewhat premature to open the 2021 melting season thread?

Here's the latest CMEMS forecast courtesy of Thomas Lavergne:

https://twitter.com/lavergnetho/status/1365758777123815424

[jdallen]

Neven I believe you have a strong bias against HYCOM which I do not understand is it because of it is associated with the US military or some other reason?

I don't consider it a bias actually.  I'm US and don't dislike the military here.  In fact I'm relieved that their pragmatism probably prevented the previous administration from burying climate change research entirely.

HYCOM unfortunately was not reliable generally.   With the new system they started using (GOFS 3.1) it has become more so, but that unfortunately reduces it's utility as a tool for examining long term trends.  I think it has utility in a general sense looking at short term trends, but I think it's predictive value isn't as good.

[Thomas Barlow]

Has ArctischePinguin retired?

No, but Wipneus usually take s a while to switch over the new year in his charts. I have the same issue myself in my volume charts.

And please don't post so many consecutive posts, some of which have been posted upthread already.

6 posts this year

<I am happy that you are participating, but cannot tolerate attacks and lashing out. O>

[Paul]

Back to the sea ice and there is some interesting weather on the way especially for the Bering Sea.

Two cyclones forecast with the second one potentially being quite a deep depression. The interesting thing for me is that wind direction in the Bering sea is going to alter between cold northerlies and less cold southerlies in the next 5 days so the sea ice will be both spreading and compacting, be interesting how it affects the numbers there.

The cyclones are also going to push very cold air into the Sea of okhotsk with winds that might suggest ice growth(again) so I'm with Jim Hunt, I'm not too convinced the maximum has been reached just yet.

[Stephan]

An increase lowers the threshold value to 0.25 ± 0.01 M km². Therefore some years move one bin to the left:

                     A       B       C
1979-1989:    3       0       8
1990-1999:    1       1       8
2000-2009:    1       1       8
2010-2020:    5       0       6       (2010, 2012, 2014, 2019 and 2020 result in "A")
sum:            10       2     30

The century increase of yesterday lowers the threshold value to 0.14 ± 0.01 M km². More years move one bin to the left:

                     A       B       C
1979-1989:    3       1       7
1990-1999:    4       2       4
2000-2009:    3       3       4
2010-2020:    6       2       3       (2010, 2011, 2012, 2014, 2018 and 2019 result in "A")
sum:            16       8     18

Another big increase will turn further years into bin "A". Maybe March 1^st for the start of the melting season thread should be delayed...

[oren]

Another big increase will turn further years into bin "A". Maybe March 1^st for the start of the melting season thread should be delayed...

Thanks Stephan.
Indeed, March 1st was predicated on a lack of rebound, while a rebound we did indeed get. Back to waiting.

BTW, kudos to those who predicted the rebound by looking at the weather.

[uniquorn]

Some peripheral seas, amsr2-uhh, feb19-27.
okhotsk, bering, atlantic side and baffin(labrador).  All scaled to 50%
bering is smaller so runs automatically, the others need a click

[uniquorn]

Wipneus UH_AMSR2_3.125km_Area_Extent-v0.0.txt is updated to feb25 at the moment

Okhotsk extent to feb25.
From the animation above I'd say it has increased more over the last couple of days.

Ice over the Yermak plateau (north of Svalbard) has taken a bit of a beating. Too cloudy to see much over the questionably thicker/thinner area closer to the pole.   https://go.nasa.gov/3e6uRJ9
Yermak is the striated circular area upper right on the second image.

[Killian]

Another big increase will turn further years into bin "A". Maybe March 1^st for the start of the melting season thread should be delayed...

Thanks Stephan.
Indeed, March 1st was predicated on a lack of rebound, while a rebound we did indeed get. Back to waiting.

BTW, kudos to those who predicted the rebound by looking at the weather.

Broken clocks and all that, but seems to have been a good call at the moment.

I think with 170k added back on in two days, leaving 140k to a new peak, that peak seems somewhat likely. Yes, the AO indicates some increased temperatures as the circumpolar weaken a bit, but neutral isn't an indicator of melt, I'd think, so we may see a slowing in ice re-growth - but that is expected to be followed by colder conditions as extrapolated from a strongly positive AO.

All this predicated on the AO doing what is roughly indicated. It doesn't always do that.

[Jim Hunt]

I'm not too convinced the maximum has been reached just yet.

Likewise!

However if a new wind blown maximum is reached then the freshly covered areas will literally be "on thin ice" and could easily depart as quickly as they arrive. With the possible exception of the thick stuff exiting via the Fram Strait in the forecast?

[Jim Hunt]

N.B. Just in case anybody else downloads the WaveWatch III wind and wave forecasts, change is afoot:

https://polar.ncep.noaa.gov/waves/ensemble/download.shtml

The EMC WAVEWATCH III® global wave model Multi-1 will be decommissioned in NCEP operations in March 2021. It will be replaced by a new configuration of the WAVEWATCH III global wave model, called GFS-Wave, and coupled to the Global Forecast System (GFSv16), as part of the Unified Forecast System.

At that time, this website will cease to update.

The silver lining is that there is now an Arctic specific GFS-Wave forecast. It seems to assume that North Cornwall is part of the Arctic, and currently reveals a significant swell heading in this direction!

[BornFromTheVoid]

Slow animation for the last week

[Freegrass]

Latest Five Day Forecast
Wind @ Surface
Large GiF!

The people from Deadliest Catch are gonna have it rough in the coming days...

[Jim Hunt]

The people from Deadliest Catch are gonna have it rough in the coming days...

Quite so!

The GFS-Wave forecast for 0Z on March 2nd:

[Thomas Barlow]

No viagra coming for the Arctic.
(or for the ageing, neglected technology)

[Paul]

I'm not too convinced the maximum has been reached just yet.

Likewise!

However if a new wind blown maximum is reached then the freshly covered areas will literally be "on thin ice" and could easily depart as quickly as they arrive. With the possible exception of the thick stuff exiting via the Fram Strait in the forecast?

Yep any ice that spreads/grows will be thin in nature. Does look like if the forecasts go to plan we should see ice growth in the sea of okhotsk especially but further growth is possible in the Barants sea. I think the Bering sea will bounce and forth a little bit as the winds keep switching direction as the lows move through.

Of course the caveats that may prevent a new maximum will be any potential ice loss in baffin bay and even the Bering sea eventually if the winds stay coming in from the ocean.

All in all, the basin does look pretty cold(as it should be at this time of year) with less cold air kept to a minimum.

[uniquorn]

Large increase in the Okhotsk sea over the last 2 days (wipneus data)

Barents had a large drop.
NERSC forecast, atlantic side, to mar7

[Freegrass]

Barents had a large drop.

That is so weird. Looking at your Gif, it seems like the ice expanded a lot along the Novaya Zemlya coast. Where did the loss come from?

[uniquorn]

Barents had a large drop.

That is so weird. Looking at your Gif, it seems like the ice expanded a lot along the Novaya Zemlya coast. Where did the loss come from?

it's a forecast to mar7

[oren]

Some peripheral seas, amsr2-uhh, feb19-27.
okhotsk, bering, atlantic side and baffin(labrador).  All scaled to 50%

FG, check out uniquorn's animation of the Barents showing the ice suddenly disappearing.

[Freegrass]

Barents had a large drop.

That is so weird. Looking at your Gif, it seems like the ice expanded a lot along the Novaya Zemlya coast. Where did the loss come from?

it's a forecast to mar7

Oops... I missed that little detail... 

The forecasted wind surely is an icemaker...

[mabarnes]

Barents had a large drop.

That is so weird. Looking at your Gif, it seems like the ice expanded a lot along the Novaya Zemlya coast. Where did the loss come from?

The answer, my friend, is blowin' in the wind.
The answer is blowin' in the wind ...

[Stephan]

The massive increase on Feb. 28 was a real game changer:

The new threshold value diminishes to 0.04 ± 0.01 M km².

                     A       B       C
1979-1989:    7       2       2
1990-1999:    8       0       2
2000-2009:    9       1       0
2010-2020:    9       0       2
sum:            33       3       6

Anything else than a new maximum of this melting season in the next days would be a real surprise.

[Killian]

I have no opinion on that.

It seems to me that a strong polar vortex for what remains of winter might increase central ice thickness slightly.

It's less clear that it would increase extent on the periphery.

I had missed this from earlier, Jim. My take is I know of no reason a positive AO would only be good for central ice. I mean, if it can freeze southern Texas on the one hand, but not all of the Arctic on the other, would that not be really weird?

Cold is cold, I think. And, as we have seen, a rebound of 270k or so so far, I'll stick with that logic for now.

Cheers

[Jim Hunt]

The massive increase on Feb. 28 was a real game changer:

Not far to go now for a new JAXA max, but the University of Hamburg's "high resolution" AMSR2 metric isn't following suit, especially when you look at sea ice area:

https://GreatWhiteCon.info/2021/02/the-2021-maximum-arctic-sea-ice-extent/#Mar-01

UH data to February 27th: