The 2020/2021 freezing season

[Freegrass]

A closer look at the Pacific weather for the next 5 days. The sea of hopscotch looks set for a major rebound, while the Bering sea ice will grow and then most likely shrink again...

[SimonF92]

A closer look at the Pacific weather for the next 5 days. The sea of hopscotch looks set for a major rebound, while the Bering sea ice will grow and then most likely shrink again...

If Okhotsk auto-corrected to "hopscotch" on your device then I find that quite amusing 

Agree with your prediction, dont often see this kind of temperature pattern

[Niall Dollard]

A closer look at the Pacific weather for the next 5 days. The sea of hopscotch looks set for a major rebound, while the Bering sea ice will grow and then most likely shrink again...

If Okhotsk auto-corrected to "hopscotch" on your device then I find that quite amusing 

Lol. Thanks for clearing that up Simon. I thought FG was referring to some hopscotch type pattern of ice in the Bering Sea. Pareidolia thread and all that !

The Sea of Hopscotch moniker - has a certain ring to it !

[Comradez]

This pattern over the next 10 days is almost the opposite of WACCy weather.  Almost kind of a Cold Arctic, Warm Continents pattern (with the unfortunate acronym CAWC, which I do not recommend speaking into your phone's voice dictation with auto-correct on). 

Sea of Hopscotch, though...I could get behind that! 

Anyways, I wonder if the CAWC pattern could actually happen to be more conducive to summer sea ice by accelerating snow albedo changes on land.  Yes, some sea ice will start out thicker.  But melt ponds might come earlier too, and stick around longer before draining...

[Paul]

This pattern over the next 10 days is almost the opposite of WACCy weather.  Almost kind of a Cold Arctic, Warm Continents pattern (with the unfortunate acronym CAWC, which I do not recommend speaking into your phone's voice dictation with auto-correct on). 

Sea of Hopscotch, though...I could get behind that! 

Anyways, I wonder if the CAWC pattern could actually happen to be more conducive to summer sea ice by accelerating snow albedo changes on land.  Yes, some sea ice will start out thicker.  But melt ponds might come earlier too, and stick around longer before draining...

One thing I have noticed over Eurasia this year is as the charts shows, the air has been much colder than many previous years(and especially last year) so I like to think because the air has been much colder, the snowcover, the ground temperatures and of course the air temperatures will be slower to warm up therefore the snowcover slower to melt away. Either way, complete contrast to last year so far which certainly make things interesting in terms of how it will all play out.

[Freegrass]

If Okhotsk auto-corrected to "hopscotch" on your device then I find that quite amusing 

I've actually been calling it the sea of Hopscotch in my head since I first learned about it here a few years ago. But I never used it on this forum. Today, I was in a funny mood, so it was time to put it out there...   

[Jim Hunt]

The NSIDC's Sea Ice Index still seems to be stuck fast, but with all the usual caveats MASIE extent has now exceeded the prior 2021 maximum:

[Shared Humanity]

Dispersion rather than freezing?

[Jim Hunt]

Dispersion rather than freezing?

That's my Arctic alter ego's current theory:

https://twitter.com/GreatWhiteCon/status/1366432566195142658

[Jim Hunt]

A photo of the storm raging in the Bering Sea courtesy of Suomi NPP earlier today:

https://go.nasa.gov/3bWqfCG

[HapHazard]

Yeah, it looks like it could be a question of compaction followed by dispersion? If so, does that say much about the state of the ice? Is this relatively unsurprising at this point of the season?

[Freegrass]

Dispersion rather than freezing?

I guess it must be both. The ice gets dispersed, and the cold open water left behind in the gaps freezes over almost instantly, while the dispersed ice cools the water at the edge, causing it to freeze over rather quickly as well.

[Jim Hunt]

The ice gets dispersed, and the cold open water left behind in the gaps freezes over almost instantly.

If it does then the satellites evidently have difficulty spotting the freshly frozen ice, otherwise "compaction" wouldn't decrease.

And if such freshly frozen ice does in fact exist, how will it fare when faced with 8 metre high "waves"?

[Freegrass]

The ice gets dispersed, and the cold open water left behind in the gaps freezes over almost instantly.

If it does then the satellites evidently have difficulty spotting the freshly frozen ice, otherwise "compaction" wouldn't decrease.

And if such freshly frozen ice does in fact exist, how will it fare when faced with 8 metre high "waves"?

If the wind is coming in from the north, over the ice, it would flatten the waves before they reach the ice edge I presume. Leaving only a gentle swell behind.

And I presume the ice in between the gaps must be too thin and wet to be picked up by the satellites?

But I'm sure more knowledgeable people than me can help us out with theses good question. I want to know if I understand. And making mistakes is the still the best way for me to learn.

[Paul]

The ice gets dispersed, and the cold open water left behind in the gaps freezes over almost instantly.

If it does then the satellites evidently have difficulty spotting the freshly frozen ice, otherwise "compaction" wouldn't decrease.

And if such freshly frozen ice does in fact exist, how will it fare when faced with 8 metre high "waves"?

In answer to your second question, the first low to hit the ice in the Bering sea probably won't have much affect as the winds quickly switch to  much colder northerlies so those wave heights probably won't last very long. The next low in a few days time may have more of an impact as the indications are the winds won't switch to colder northerlies but the air wrapped around it remains quite cold so the Bering sea is not going too see a warm up as such but compaction could mean some ice loss although more compact ice may mean a slower melt when the warmer temperatures eventually arrives.

[Stephan]

No "ABC" analysis today, because a new JAXA extent maximum has been reached (for details see the "area and extent data" thread).
The opening of the melting season thread has to be postponed. For how long? I don't know.

[Freegrass]

Dispersion rather than freezing?

I guess it must be both. The ice gets dispersed, and the cold open water left behind in the gaps freezes over almost instantly, while the dispersed ice cools the water at the edge, causing it to freeze over rather quickly as well.

I think I need to make a correction to this. Of course the cold northerly wind in the sea of Okhotsk will cool the ocean and freeze the water. So while some dispersion must be a fact, the ice edge will mostly grow due to the cold wind cooling and freezing the ocean I presume.

In the Barents sea my first explanation would make more sense, because I assume the water is still too warm and salty there to freeze over from cold wind alone? Although Mercator does show a pretty cold Barents sea...

[Killian]

No "ABC" analysis today, because a new JAXA extent maximum has been reached (for details see the "area and extent data" thread).
The opening of the melting season thread has to be postponed. For how long? I don't know.

That came a bit more quickly than I had originally expected. We should see it continue higher through to near mid-month unless there is something that disrupts the circumpolar winds. That seems unlikely as the AO forecast is only going even more strongly positive. +3.5 is the lower bound (except for one run), and it's going as high as +6 now. Mean seems to be between 4.5 and 5, eyeballing it?

But.... with the AO potentially going to +6 over the next week or so, I wonder how much thickening we might get.... could it end up making a difference?

Not that this new ice matters much. When freeze-up came earlier - I mean overall, not necessarily peak - so that a greater area of the ice had longer to thicken and harden, the peak extent was more meaningful, I think. Now with so little of the refreeze happening early on, that downward spiral is just going to go on and on.

[Jim Hunt]

Several of the wave buoys in the Bering Sea are out of action at the moment, but buoy 46073 managed to record this:

https://GreatWhiteCon.info/2021/02/the-2021-maximum-arctic-sea-ice-extent/#comment-406461

[Niall Dollard]

The second mercator ocean image you posted above FG, is showing few significantly cold anomalies south of Cape Farewell, where we would usually be expecting to see the "cold blob".

Perhaps the blob waxes and wanes a bit and will become more obvious again when we are deep into the melt season.

[Freegrass]

The second mercator ocean image you posted above FG, is showing few significantly cold anomalies south of Cape Farewell, where we would usually be expecting to see the "cold blob".

Perhaps the blob waxes and wanes a bit and will become more obvious again when we are deep into the melt season.

I'm confused, because on Nullschool there is no sign of the cold blob anymore this year.

Did they change their data source again? It says Source | OSTIA / UK Met Office + GHRSST + CMEMS now.

On another note, but relevant to an earlier post about Ice thickness in the arctic basin, Mercator is kind of in agreement with HYCOM it seems.

How can we find out the facts when everyone is telling a different story? 

(alcohol day)

Adding HYCOM Sea Surface temperature for the last 30 days

[Niall Dollard]

This is a good link (from NOAA PSL) to keep an eye on SST anomalies.

https://psl.noaa.gov/map/clim/sst.anom.anim.year.html

It shows the blob waning in August, coming back in November and then diminishing in February.

With these anomaly maps (and same for temperature anomalies) you do need to keep an eye on reference periods. Some too are in the process of changing to 1991-2020.

But I'm getting O/T now and probably best discuss SSTs in a separate thread

[Jim Hunt]

The rate of JAXA extent increase is decreasing:

https://GreatWhiteCon.info/2021/02/the-2021-maximum-arctic-sea-ice-extent/#Mar-03

Plus a pseudo-colour glimpse of the Bering Sea ice edge after the cyclone.

[Freegrass]

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

The arctic weather is quite interesting in the coming days, with lots going on in the Fram Strait, Barents and Bering sea, but most interestingly for the coming melting season IMHO is that the ESS will see more ice blown into it.

[Freegrass]

HYCOM is already showing the effects of the wind that is forecasted to blow the ice pack towards the ESS. The buildup of ice along the ESS coast is clearly visible. The reds are deeper in the ESS now than along the Canadian coast. 

A big increase in the sea of Okhotsk can also be seen, while the ice in the Bering sea doesn't seem to be affected by the southerly wind as much as the northerly that preceded it.

The Barents sea ice doesn't seem to be able to recover what it lost.

But I'm mostly curious to see if the numbers will confirm what HYCOM is predicting...

[Jim Hunt]

I'm mostly curious to see if the numbers will confirm what HYCOM is predicting...

Whereas I'm curious about the differences between the CS2/SMOS, PIOMAS and GOFS thickness maps:

https://GreatWhiteCon.info/2021/03/the-2021-maximum-arctic-sea-ice-volume/

[Freegrass]

I'm mostly curious to see if the numbers will confirm what HYCOM is predicting...

Whereas I'm curious about the differences between the CS2/SMOS, PIOMAS and GOFS thickness maps:

https://GreatWhiteCon.info/2021/03/the-2021-maximum-arctic-sea-ice-volume/

I'll be a furious defender of HYCOM this season. It's up to others to poke holes in it so we can all figure out WTH is going on...

If at the end of the season it is proven that HYCOM is wrong, I will have no problem with that.

If HYCOM is proven right, we will have a great visual tool for the future...

EDIT: The PIOMAS model you posted actually agrees more with HYCOM than with SMOS it seems. Especially the white (thick ice) in the ESS and along the CAA.

The big question is the thick ice measured by SMOS at the mouth of Fram Strait that HYCOM isn't showing. PIOMAS seems to be closer to HYCOM again then SMOS if my eyes aren't fooling me...

And lets not forget Mercator. How trustworthy are they?

(these two images are from the same day. Just a different color bar)

[grixm]

As for volume models, there's also Nico Sun's AMSR2 SIT model, which recently received an upgrade. I don't see it discussed here very often.

https://cryospherecomputing.tk/SIT.html

[Glen Koehler]

         To help compare the different Volume models, here are PIOMAS and HYCOM rotated to more closely match the others.
     Edit:  As per Oren and Freegrass comments, AMSR2 image and editorial comment removed.

[oren]

Thanks for the rotation Glen.

AMSR2 thickness measurement is too unreliable as to be quite useless IIRC, best not to discuss it in this thread. Wipneus explained it once, I think there's a thread somewhere with this info.

[Freegrass]

Me thinks tthat his discussion belongs in a different thread

I don't agree. This is the freezing season thread, and what we're doing is trying to figure out what the ice really looks like right now by comparing the different models and measurements so we can come to a conclusion and the end of this season before the thread is closed.

To continue the debate about different models during the melting season, I would agree that its better to have that discussion in another thread - as to not clog up the melting season thread with constant bikkering about different models. But for now, I think its very usefull to compare the different models at the end of this season. That way we can come back at this on a later date to see which model was closer to the truth.

[oren]

What the ice does, will do and did belongs here.
Deep discussion into the various thickness models and their relative or absolute merits - not here.
PIOMAS, CS2SMOS, and Hycom considered relatively reliable for ice purposes, and can be posted freely. I guess Mercator too though am unfamiliar with it.
DMI and AMSR2 thickness/volume not considered reliable enough, and can be posted here occasionally and sparingly, or (better) discussed in their own threads.

[Paul]

I'm mostly curious to see if the numbers will confirm what HYCOM is predicting...

Whereas I'm curious about the differences between the CS2/SMOS, PIOMAS and GOFS thickness maps:

https://GreatWhiteCon.info/2021/03/the-2021-maximum-arctic-sea-ice-volume/

Like last year, Im a little skeptical of those charts because if a colder freezing season than 16/17 produces less volume even with a negative AO then there could be a fault with the model and during the 16/17 season, the PIOMAS and cryosat did disagree but the other way with PIOMAS showing much less volume than cryosat. The theory was maybe the cryostat model was getting fooled by increased snowfall and counting it as thicknesses. Given high pressure has been more in control this winter, I will assume there is less snowfall on the ice pack this year and maybe that is why its showing a lower reading.

Given the weather conditions we seen during the winter and looking at worldview, I will go along with the ice is probably thicker in the Beaufort sea due to multi year ice, the ice is thicker over the Siberian Arctic due to compaction and the ice is quite thin over/near the pole due to first year ice and somewhat higher temperatures.

[Freegrass]

I'm mostly curious to see if the numbers will confirm what HYCOM is predicting...

Whereas I'm curious about the differences between the CS2/SMOS, PIOMAS and GOFS thickness maps:

https://GreatWhiteCon.info/2021/03/the-2021-maximum-arctic-sea-ice-volume/

Like last year, Im a little skeptical of those charts because if a colder freezing season than 16/17 produces less volume even with a negative AO then there could be a fault with the model and during the 16/17 season, the PIOMAS and cryosat did disagree but the other way with PIOMAS showing much less volume than cryosat. The theory was maybe the cryostat model was getting fooled by increased snowfall and counting it as thicknesses. Given high pressure has been more in control this winter, I will assume there is less snowfall on the ice pack this year and maybe that is why its showing a lower reading.

Given the weather conditions we seen during the winter and looking at worldview, I will go along with the ice is probably thicker in the Beaufort sea due to multi year ice, the ice is thicker over the Siberian Arctic due to compaction and the ice is quite thin over/near the pole due to first year ice and somewhat higher temperatures.

The lower volume is perfectly explainable IMHO because of the late refreeze and the increased ocean temperature at depth that was explained in a paper posted last year. There's just too much heat in the arctic ocean. And this heat is able to prevent freezing because of a thinning mixing layer rising halocline. (hope I remembered this correctly)

[Paul]

I'm mostly curious to see if the numbers will confirm what HYCOM is predicting...

Whereas I'm curious about the differences between the CS2/SMOS, PIOMAS and GOFS thickness maps:

https://GreatWhiteCon.info/2021/03/the-2021-maximum-arctic-sea-ice-volume/

Like last year, Im a little skeptical of those charts because if a colder freezing season than 16/17 produces less volume even with a negative AO then there could be a fault with the model and during the 16/17 season, the PIOMAS and cryosat did disagree but the other way with PIOMAS showing much less volume than cryosat. The theory was maybe the cryostat model was getting fooled by increased snowfall and counting it as thicknesses. Given high pressure has been more in control this winter, I will assume there is less snowfall on the ice pack this year and maybe that is why its showing a lower reading.

Given the weather conditions we seen during the winter and looking at worldview, I will go along with the ice is probably thicker in the Beaufort sea due to multi year ice, the ice is thicker over the Siberian Arctic due to compaction and the ice is quite thin over/near the pole due to first year ice and somewhat higher temperatures.

The lower volume is perfectly explainable IMHO because of the late refreeze and the increased ocean temperature at depth that was explained in a paper posted last year. There's just too much heat in the arctic ocean. And this heat is able to prevent freezing because of a thinning mixing layer rising halocline. (hope I remembered this correctly)

That could be a factor, refreeze was certainly delayed in the Siberian seas but more 'normal' (for modern times) in other seas like the Beaufort and the Chukchi. That said, with the winter weather patterns being more high pressure dominated, it has allowed regions like the Laptev and especially the ESS in particular to catch up in thicknesses and are way more thicker than they were last year. Similar to 2018 perhaps.

The CAB is a concern, some of the low volume may be explained that ice looks less thicker against the CAA but the area from the Barants sea upto near the pole has got ice according to the models quite thin. Be interesting if the upcoming weather patterns may help with that or not. However with the open water seperating the ice pack aand Svalbard unlikely to fully freeze over, it will probably mean the ice in the Barants sea will quickly melt(like in 2018) and we could see Atlantification being quite severe again.

All very interesting and the CAB still has a little bit more time to get thicker. The weather patterns are interesting as it suggests the CAB will have the coldest temperatures but whilst the GFS is going for a large deep cyclone to dominate the basin, the euro models suggests high pressure will still play a role near the pole.

Also I suspect we may see signs of the Beaufort Gyre kicking into gear. May see quite alot of cracks appearing in the Beaufort sea.

[Jim Hunt]

The theory was maybe the cryostat model was getting fooled by increased snowfall and counting it as thicknesses. Given high pressure has been more in control this winter, I will assume there is less snowfall on the ice pack this year and maybe that is why its showing a lower reading.

The CryoSat-2 "error bars" are quite large. However I find it hard to believe that snowfall variations can explain away the area of apparently thicker ice located between the Pole and the Fram Strait, which is visible in CS2 and (offset a bit) in PIOMAS but not in the other models.

At least they all seem to agree that a band of thicker ice has built up on Siberian shores.

[Comradez]

Right now everyone is looking at sea ice thickness, which is understandable because that is what this website is all about, but I would encourage people to keep an eye equally on snow extent this spring. 

Right now the Barentsz and Kara Seas are very cold, and are likely to have recovered from their ultra-late refreeze this winter.  But it is coming at the cost of warmer temperatures and lower snow extent in Europe, the Caucasus, and Central Asia which is set to bootstrap albedo changes and snow melt along the snow melt frontiers there, bringing warm air advection to the Kara and Barentsz at earlier dates.  Similarly, the CAA has been cold, but the snow melt frontier has been warm in North America and is set to stay that way for the next 10-14 days. 

The only year in recent history with a similar strongly negative snow melt anomaly at this date was 2016.  Interestingly, 2012 was nothing special for snow-melt at this point (actually, significantly above-average snow extent  on 3/4).  2012's snow melt only zoomed into high gear later.   

[Freegrass]

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

It's getting very windy up there...
Will the Svalbard gap close up a little?

[Killian]

The rate of JAXA extent increase is decreasing:

https://GreatWhiteCon.info/2021/02/the-2021-maximum-arctic-sea-ice-extent/#Mar-03

Plus a pseudo-colour glimpse of the Bering Sea ice edge after the cyclone.

Of course. As expected given the AO diving down to -1, as had been expected to happen. Refreeze should pick up again over the the next week then be on the road down from there.

[Paul]

The theory was maybe the cryostat model was getting fooled by increased snowfall and counting it as thicknesses. Given high pressure has been more in control this winter, I will assume there is less snowfall on the ice pack this year and maybe that is why its showing a lower reading.

The CryoSat-2 "error bars" are quite large. However I find it hard to believe that snowfall variations can explain away the area of apparently thicker ice located between the Pole and the Fram Strait, which is visible in CS2 and (offset a bit) in PIOMAS but not in the other models.

At least they all seem to agree that a band of thicker ice has built up on Siberian shores.

It's a theory Neven and a few others have said, seems plausible as despite the cool summer in 2017, ice was diffused in large areas even in the CAB by September. PIOMAS is not perfect but it called last years melt season quite well of weaker more vulnable ice in the Siberian regions and thicker ice over the CAB and the Beaufort sea. Sadly warm SSTS and temperatures overridden the thicknesses in the CAB hence the ice edge reaching 85degrees north quite widely.

Right now the Barentsz and Kara Seas are very cold, and are likely to have recovered from their ultra-late refreeze this winter.  But it is coming at the cost of warmer temperatures and lower snow extent in Europe, the Caucasus, and Central Asia which is set to bootstrap albedo changes and snow melt along the snow melt frontiers there, bringing warm air advection to the Kara and Barentsz at earlier dates. 

I'm not too sure if any warm air will come in earlier over the Barants and Kara seas, of course weather patterns play a part also but too me compared to some years, western Russia has been and is forecast to be colder so in theory snowfall should be slower to retreat, slower than last year surely? Asia has been warmer than average and this has had an affect on snow cover but given February was below normal over Siberia, I like to think as the snow cover retreats, it will find it harder at the higher latitudes, I know it does not always work that way but will be interesting too see in the next 2 months.

[Freegrass]

Dispersion rather than freezing?

I guess it must be both. The ice gets dispersed, and the cold open water left behind in the gaps freezes over almost instantly, while the dispersed ice cools the water at the edge, causing it to freeze over rather quickly as well.

I think I need to make a correction to this. Of course the cold northerly wind in the sea of Okhotsk will cool the ocean and freeze the water. So while some dispersion must be a fact, the ice edge will mostly grow due to the cold wind cooling and freezing the ocean I presume.

In the Barents sea my first explanation would make more sense, because I assume the water is still too warm and salty there to freeze over from cold wind alone? Although Mercator does show a pretty cold Barents sea...

I think I need to correct again...

Can anyone help me out here and tell me what that cold northerly did with the ice edge in the sea of hopscotch? Was my first intuition right? I see lots of thick ice it seems at the edge, so no new frozen ocean. Or am I seeing it wrong? I still have lots to learn about the ice edge it seems... 

https://go.nasa.gov/3bkjJ9y

[Freegrass]

NSIDC is back again...

[Jim Hunt]

NSIDC is back again...

Indeed it is, and AMRS2 area has also reached a new maximum for the year at long last:

https://GreatWhiteCon.info/2021/02/the-2021-maximum-arctic-sea-ice-extent/#Mar-06

[Jim Hunt]

PIOMAS is not perfect...

But it seems to me to have a better idea of where the thicker ice is currently to be found than GOFS/HYCOM:

https://GreatWhiteCon.info/2021/03/the-2021-maximum-arctic-sea-ice-volume/#Mar-06

See this ASCAT animation of the 2020/21 freezing season for example:

[oren]

Thank you for this animation Jim. ASCAT is a great resource during the freezing season.

[nadir]

The recent recuperation of the polar vortex has led to a colder Arctic, and in parallel the anomalous snows that Jan and Feb had left over vast regions of the NH particularly US and Europe have not persisted.

[Pavel]

A strong 968 hPa cyclone is going to set up. It may cause the ice break up in the Beaufort and Siberian seas. The early opening up in the Beaufort sea in repeating the 2016 pattern may destroy our best ice this year

[Jim Hunt]

The extremely tentative new JAXA maximum extent is 14.14 million km² on March 5th:

https://GreatWhiteCon.info/2021/02/the-2021-maximum-arctic-sea-ice-extent/#Mar-07

Plus the GOFS drift forecast which shows the cyclone mentioned by Pavel.

Click to animate.

[BornFromTheVoid]

Slow animation for the week. Bering Sea fluctuating with the storms, regrowth in Okhotsk, Barents and Greenland Seas.
The continuation of ice free conditions in the Gulf of St Lawrence and losses in Baffin Bay are interesting.

[Stephan]

BFTV, thank you for these slow animations and the colour-coded gains and losses.