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Niall Dollard

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Re: The 2020/2021 freezing season
« Reply #750 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 on Oct 17th. Back then PSL indicated it was only about 20cm thick.

Since then it has only slightly thickened by about 10cm. 

jdallen

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Re: The 2020/2021 freezing season
« Reply #751 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
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aslan

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Re: The 2020/2021 freezing season
« Reply #752 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.
« Last Edit: November 10, 2020, 07:31:57 AM by aslan »

El Cid

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Re: The 2020/2021 freezing season
« Reply #753 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

bbr2315

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Re: The 2020/2021 freezing season
« Reply #754 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.

aslan

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Re: The 2020/2021 freezing season
« Reply #755 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.
« Last Edit: November 10, 2020, 02:47:00 PM by aslan »

BornFromTheVoid

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Re: The 2020/2021 freezing season
« Reply #756 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.
I recently joined the twitter thing, where I post more analysis, pics and animations: @Icy_Samuel

uniquorn

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Re: The 2020/2021 freezing season
« Reply #757 on: November 10, 2020, 07:18:45 PM »
I referred to this weak area in this post 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


uniquorn

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Re: The 2020/2021 freezing season
« Reply #758 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.

Vince O

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Re: The 2020/2021 freezing season
« Reply #759 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. :@)

uniquorn

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Re: The 2020/2021 freezing season
« Reply #760 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
« Last Edit: November 10, 2020, 08:20:56 PM by uniquorn »

BornFromTheVoid

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Re: The 2020/2021 freezing season
« Reply #761 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.
I recently joined the twitter thing, where I post more analysis, pics and animations: @Icy_Samuel

aslan

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Re: The 2020/2021 freezing season
« Reply #762 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.

aslan

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Re: The 2020/2021 freezing season
« Reply #763 on: November 10, 2020, 10:22:51 PM »
Er... I still don't know how to make it an other way.

aslan

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Re: The 2020/2021 freezing season
« Reply #764 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...
« Last Edit: November 10, 2020, 10:39:28 PM by aslan »

uniquorn

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Re: The 2020/2021 freezing season
« Reply #765 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
« Last Edit: November 10, 2020, 11:13:35 PM by uniquorn »

VeliAlbertKallio

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Re: The 2020/2021 freezing season
« Reply #766 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
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VeliAlbertKallio

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Re: The 2020/2021 freezing season
« Reply #767 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
"Setting off atomic bombs is considered socially pungent as the years are made of fleeting ice that are painted by the piling up of the rays of the sun."

uniquorn

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Re: The 2020/2021 freezing season
« Reply #768 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.
« Last Edit: November 11, 2020, 12:45:58 PM by uniquorn »

BornFromTheVoid

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Re: The 2020/2021 freezing season
« Reply #769 on: November 11, 2020, 06:14:20 PM »
A short animation focusing on the October temperature changes in the eastern Arctic.

I recently joined the twitter thing, where I post more analysis, pics and animations: @Icy_Samuel

Glen Koehler

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Re: The 2020/2021 freezing season
« Reply #770 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.
« Last Edit: November 12, 2020, 06:29:37 AM by Glen Koehler »

binntho

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Re: The 2020/2021 freezing season
« Reply #771 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.
because a thing is eloquently expressed it should not be taken to be as necessarily true
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Aluminium

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Re: The 2020/2021 freezing season
« Reply #772 on: November 12, 2020, 06:57:36 AM »
November 2-11.

2019.

jdallen

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Re: The 2020/2021 freezing season
« Reply #773 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.
This space for Rent.

gerontocrat

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Re: The 2020/2021 freezing season
« Reply #774 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.
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El Cid

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Re: The 2020/2021 freezing season
« Reply #775 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

uniquorn

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Re: The 2020/2021 freezing season
« Reply #776 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
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
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
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.
« Last Edit: November 12, 2020, 01:00:14 PM by uniquorn »

binntho

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Re: The 2020/2021 freezing season
« Reply #777 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.
because a thing is eloquently expressed it should not be taken to be as necessarily true
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El Cid

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Re: The 2020/2021 freezing season
« Reply #778 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

grixm

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Re: The 2020/2021 freezing season
« Reply #779 on: November 12, 2020, 02:17:28 PM »
The freezing days anomaly has been following the record 2016 very closely so far.

binntho

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Re: The 2020/2021 freezing season
« Reply #780 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!
because a thing is eloquently expressed it should not be taken to be as necessarily true
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BornFromTheVoid

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Re: The 2020/2021 freezing season
« Reply #781 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
I recently joined the twitter thing, where I post more analysis, pics and animations: @Icy_Samuel

romett1

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Re: The 2020/2021 freezing season
« Reply #782 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

uniquorn

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Re: The 2020/2021 freezing season
« Reply #783 on: November 12, 2020, 08:51:07 PM »
~7days raw buoy data from iabp
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.
« Last Edit: November 13, 2020, 01:04:41 AM by uniquorn »

Positive retroaction

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Re: The 2020/2021 freezing season
« Reply #784 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
Sorry, excuse my bad english

uniquorn

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Re: The 2020/2021 freezing season
« Reply #785 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

Vince O

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Re: The 2020/2021 freezing season
« Reply #786 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.

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Re: The 2020/2021 freezing season
« Reply #787 on: November 13, 2020, 12:58:26 AM »


..., 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).
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uniquorn

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Re: The 2020/2021 freezing season
« Reply #788 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/

Vince O

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Re: The 2020/2021 freezing season
« Reply #789 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

UCMiami

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Re: The 2020/2021 freezing season
« Reply #790 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.

Positive retroaction

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Re: The 2020/2021 freezing season
« Reply #791 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.
« Last Edit: November 13, 2020, 10:14:24 PM by Positive retroaction »
Sorry, excuse my bad english

uniquorn

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Re: The 2020/2021 freezing season
« Reply #792 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

« Last Edit: November 13, 2020, 11:15:51 PM by uniquorn »

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Re: The 2020/2021 freezing season
« Reply #793 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>
« Last Edit: November 14, 2020, 12:06:27 AM by oren »

uniquorn

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Re: The 2020/2021 freezing season
« Reply #794 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.


 

BornFromTheVoid

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Re: The 2020/2021 freezing season
« Reply #795 on: November 14, 2020, 12:36:37 PM »
Slow sea ice animation, November 6th to 13th. Large file, so click to play
I recently joined the twitter thing, where I post more analysis, pics and animations: @Icy_Samuel

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Re: The 2020/2021 freezing season
« Reply #796 on: November 14, 2020, 03:22:53 PM »
Vize anomaly is +16,5°C and tonight maybe highter
Sorry, excuse my bad english

bbr2315

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Re: The 2020/2021 freezing season
« Reply #797 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.



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.

« Last Edit: November 14, 2020, 03:54:25 PM by bbr2315 »

oren

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Re: The 2020/2021 freezing season
« Reply #798 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.

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Re: The 2020/2021 freezing season
« Reply #799 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
Sorry, excuse my bad english