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Frivolousz21

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Re: The 2020 melting season
« Reply #2450 on: July 09, 2020, 12:46:35 AM »
The 850mb temps at 12Z today are just INSANE.

And also the Kara SSTS are boiling.

A huge area where the water depth is like 8-20 meters is running 8-10C.

Assuming there could be a lot of methane release with that

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Re: The 2020 melting season
« Reply #2451 on: July 09, 2020, 12:54:26 AM »
7/1-7/7 click it

Comradez

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Re: The 2020 melting season
« Reply #2452 on: July 09, 2020, 01:03:32 AM »
Today there is a nice clear view of Ellesmere Island around Lake Hazen, which will probably be ice free in a day or two.  I thought to compare it with the year 2000 for curiosity's sake (as far back as worldview images go).  The closest cloud-free day I could find in the year 2000 was July 27th (19 days later).  Check it out https://worldview.earthdata.nasa.gov/?v=-760542.2261382015,-970911.7625952777,-64222.22613820154,-634527.7625952777&p=arctic&t=2000-07-27-T14%3A00%3A00Z&t1=2020-07-08-T16%3A00%3A00Z&l1=Reference_Labels(hidden),Reference_Features(hidden),Coastlines,VIIRS_NOAA20_CorrectedReflectance_TrueColor(hidden),VIIRS_SNPP_CorrectedReflectance_TrueColor(hidden),MODIS_Aqua_CorrectedReflectance_TrueColor(hidden),MODIS_Terra_CorrectedReflectance_TrueColor&ca=true&cv=47

I noticed right off the bat that the glaciers on northern Ellesmere and especially NW Greenland have shrunk considerably and also darkened.  And keep in mind that this is 19 days later in the year in the year 2000. 

Michael Hauber

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Re: The 2020 melting season
« Reply #2453 on: July 09, 2020, 01:20:21 AM »
Lots of surface melt near the north pole.  But no clues of what might be going on below, no matter how long I stare at it.
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Paul

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Re: The 2020 melting season
« Reply #2454 on: July 09, 2020, 03:57:32 AM »
I do believe some of the extent losses would of occurred regardless of the high pressure as ice extent in places were thin in anycase. I do believe compaction in the CAB is better for the ice longer in the melt season than dispersion would be. You only need too see 2016 how dispersion can affect things and actually arguably give a misleading extent total.

You do worry if some deep low pressure systems do come into play though but as others say, it's high pressure that rules the roost with the exception of the Beaufort but there is hints in the longer term this high may head there eventually which of course increases the chances of the infamous dipole.

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Re: The 2020 melting season
« Reply #2455 on: July 09, 2020, 06:04:55 AM »


Was looking at ice during Winter freeze up and thought God that ice is going to have to freeze lots to avoid catastrophe next Summer. And it did. But look now.


This is an important point. Last winter, the polar vortex was about as strong as ever recorded. There was more cold air over the arctic than we have seen in many years.

It was a great freezing season! However, the thermodynamics of ice formation limits what can happen in a given year, regardless of the temperature. This is a fundamental misunderstanding of a certain prolific poster.

This is melting thread, so I don’t want to go off topic. But, remember thermodynamics controls the ice, and one cold winter can not affect the thickness of the overall ice sheet by very much.

It would take several cold winters, without significant melting during intervening summers, to make the ice healthy again.



Killian

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Re: The 2020 melting season
« Reply #2456 on: July 09, 2020, 08:50:09 AM »
Just a quick observation that this graphic of ice movement has pointed straight down the throat of Fram Strait every time I have looked at it this season. That has been sporadic, which also means it has been random, but I have seen it look no other way this season.

That's 2012, folks.

Worse, I have noticed anything mentioned about dipoles setting up, but in 2012 it was the dipole phenomenon that dominated the rush of ice out of Fram Strait, iirc.

That's not 2012, folks, yet here we are watching it flow out into oblivion.

I was certain of a new 2nd lowest record this year as of a bit more than a month ago. Now? I'm wondering if it might not just be a new record, period.

All this speaks to my contention we hit a phase shift in recent years and that phase shift is an overall increase in warming. What else explains the temps and events we're seeing?

And that so much of the melt is over the ESS is disconcerting at best.

If someone has a whisker of a hope as to why the summer will shift to the typical favorable low melt conditions we've seen pretty much every summer since 2012, please share them. If this season is as bad as it seems to be shaping up to, that canary is good and dead.


Aluminium

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Re: The 2020 melting season
« Reply #2458 on: July 09, 2020, 09:48:32 AM »
July 4-8.

2019.

bluice

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Re: The 2020 melting season
« Reply #2459 on: July 09, 2020, 10:07:34 AM »
July 4-8.

2019.
Literally the only place ice edge is not moving north/nortwest is Fram Strait.

Killian

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Re: The 2020 melting season
« Reply #2460 on: July 09, 2020, 11:47:00 AM »
I do believe compaction in the CAB is better for the ice longer in the melt season than dispersion would be. You only need too see 2016 how dispersion can affect things and actually arguably give a misleading extent total.

I don't think the lowered extent is misleading if one bears in mind context. The same extent with very dispersed ice on one hand and compacted ice on the other are not the same. I understand what you meant by misleading, but it's just not the most accurate way to talk about it, maybe?

I think you mean a low extent due to compactions is good better overall than more dispersed ice with a higher extent. Not misleading, just different animals.

ArcticMelt2

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Re: The 2020 melting season
« Reply #2461 on: July 09, 2020, 11:48:44 AM »
https://twitter.com/ZLabe/status/1280869972713996289

Quote
No improvement to #Arctic sea ice conditions around Siberia. The record early loss continues...



https://twitter.com/AlaskaWx/status/1280904696366985221

Quote
#Arctic-wide #seaice extent from @NSIDC passive microwave data for July 07 is lowest in the satellite era. However, Alaska is not playing along. Combined ice extent in Beaufort & Chukchi Seas is highest since 2013 & just below the long term average. #akwx @Climatologist49 @ZLabe


blumenkraft

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Re: The 2020 melting season
« Reply #2462 on: July 09, 2020, 12:03:30 PM »
If you zoom out in RAMMB-SLIDER on Day&Night band and you can still see the melt ponds in the middle of the ice pack, you know things are not looking good.

Tom_Mazanec

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Re: The 2020 melting season
« Reply #2463 on: July 09, 2020, 01:44:50 PM »
Quote
It would take several cold winters, without significant melting during intervening summers, to make the ice healthy again.
With AGW, that is a weight of 350 pounds probability...i.e. "fat chance".

grixm

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Re: The 2020 melting season
« Reply #2464 on: July 09, 2020, 02:10:35 PM »
While extent continues to drop, area has actually stalled for the last 4 days. More draining melt ponds?


werther

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Re: The 2020 melting season
« Reply #2465 on: July 09, 2020, 02:15:56 PM »
Ive not been watching as intense as earlier years. So if I do now, I must be modest. Even so, what can be seen is worrying. Lots of sunshine over the CAB. On Worldview the snow seems to be gone completely, leaving vast stretches of melt ponds. Structure doesn't look good too. Once there were large rhomboid ice stretches between the leads. They seem to have crumbled everywhere.
In retrospect, may warmth seems to have prepared te scene for heavy melting...
Is this going to be a/the sad year?

PragmaticAntithesis

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Re: The 2020 melting season
« Reply #2466 on: July 09, 2020, 02:26:52 PM »
While extent continues to drop, area has actually stalled for the last 4 days. More draining melt ponds?

Well, there are a lot of melt ponds to drain...
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gandul

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Re: The 2020 melting season
« Reply #2467 on: July 09, 2020, 02:43:47 PM »
I think there is a vast ring north of 80N and the Beaufort sea where surface melting is weaker than a few days ago. This half ring (marked in a Trump-esque way below) is getting colder air than the Atlantic counterpart which is dragging the heat literally from Laptev.
Beaufort sea has been under a weak low and is colder than Chukchi and ESS.
Extent loss is more driven by compaction, not affected by all this.

Pagophilus

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Re: The 2020 melting season
« Reply #2468 on: July 09, 2020, 03:33:14 PM »
While extent continues to drop, area has actually stalled for the last 4 days. More draining melt ponds?

Well, there are a lot of melt ponds to drain...

         
Central Arctic  Ocean Seas         
Chukchi______   -14    k   loss
Beaufort_____   -0    k   loss
CAA_________    9    k   gain
East Siberian__   -29    k   loss
Central Arctic_    7    k   gain
Laptev_______   -8    k   loss
Kara_________   -9    k   loss


And, backing up your point, the Central Arctic showed that 7k gain yesterday, while everything around it was losing area.  Except the CAA which has been baby-blue with meltponds for some time now.  So draining meltponds seems a likely suspect.
« Last Edit: July 09, 2020, 04:05:08 PM by Pagophilus »
You may delay, but time will not.   Benjamin Franklin.

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Re: The 2020 melting season
« Reply #2469 on: July 09, 2020, 03:43:08 PM »
While extent continues to drop, area has actually stalled for the last 4 days. More draining melt ponds?

 where is that graph from ? what is it showing? 
.. and why does it bear no relation to Gerontocrat's updates or what appears to be happening ? b.c.
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grixm

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Re: The 2020 melting season
« Reply #2470 on: July 09, 2020, 03:51:32 PM »
While extent continues to drop, area has actually stalled for the last 4 days. More draining melt ponds?

 where is that graph from ? what is it showing? 
.. and why does it bear no relation to Gerontocrat's updates or what appears to be happening ? b.c.

It is from https://cryospherecomputing.tk/ and it shows the NSIDC daily area. It has not fully shown up in gerontocrat's charts yet because he uses 5-day averages, but it will soon. Even today will be significantly lower loss than yesterday in his data.

Phoenix

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Re: The 2020 melting season
« Reply #2471 on: July 09, 2020, 03:59:49 PM »
Was looking at ice during Winter freeze up and thought God that ice is going to have to freeze lots to avoid catastrophe next Summer. And it did. But look now.
thermodynamics controls the ice, and one cold winter can not affect the thickness of the overall ice sheet by very much.
In late October 2019, volume was basically tied for lowest volume for the date. In early March 2020, volume had fallen to 9th position.

The difference in volume gain in this 4.5 month period vs. the same period in the winter of 2016-17 was ~ 2,600 km3.

Volume gains in a single freezing season have benefit beyond a simple layer of "fat" to provide a buffer for the melting season. Achieving certain thickness thresholds limits bottom melt in the subsequent melting season by limiting EMR penetration beneath the ice.... an important positive feedback effect which is currently quite important.
« Last Edit: July 09, 2020, 08:14:21 PM by oren »

Pagophilus

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Re: The 2020 melting season
« Reply #2472 on: July 09, 2020, 04:01:28 PM »
ESS has been modestly concealed beneath clouds for some days now on Worldview.  Today's Worldview has a portion of the sea visible.  Contrast tweaked to bring out the difference between clouds and ice.  Ice that is visible is looking rather sad, as might be expected.
You may delay, but time will not.   Benjamin Franklin.

Csnavywx

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Re: The 2020 melting season
« Reply #2473 on: July 09, 2020, 04:07:54 PM »
Yes, worldview shows widespread melt pond draining the past few days. Another week of this and in situ open water fraction will rapidly start to increase as the rot deepens.

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Re: The 2020 melting season
« Reply #2474 on: July 09, 2020, 04:14:04 PM »
ta grixm  .. as it's very obvious actual area is shrinking during the last 4 days I suppose it must be assumed the drainage of melt ponds has helped cancel out the real decline ..
  open water has moved from 82.1'N to 82.8'N over the last week . If the current rate of melt/retreat continued , open water would reach the pole by mid September . Of course bottom melt could accelerate this and a change in weather could postpone it for another year .. b.c.
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Phoenix

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Re: The 2020 melting season
« Reply #2475 on: July 09, 2020, 04:16:22 PM »
Thanks once more, Aluminium

To my eye, your animation appears to show the ice pack edge on the Atlantic side starting to align obediently above the 200m submarine contour in this area, as is it often does.

Much more speculatively, the same currently could be said of the ice edge starting to align with 200m contour along the the northern margin of the Laptev Sea. 


That's a good observation Pagophilus.

One big difference between those two isobaths is that the Laptev 200m line is just a few degrees latitude removed from the Asian continent where the Taymyr Peninsula juts out to 77N. The continuous assault of WAA from land and the warmed Laptev Sea will make it easy to push beyond the 200m line.

The sources for WAA on the Atlantic side are much less profound and that line is much more consistently maintained.

Paul

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Re: The 2020 melting season
« Reply #2476 on: July 09, 2020, 04:27:34 PM »
I do believe compaction in the CAB is better for the ice longer in the melt season than dispersion would be. You only need too see 2016 how dispersion can affect things and actually arguably give a misleading extent total.

I don't think the lowered extent is misleading if one bears in mind context. The same extent with very dispersed ice on one hand and compacted ice on the other are not the same. I understand what you meant by misleading, but it's just not the most accurate way to talk about it, maybe?

I think you mean a low extent due to compactions is good better overall than more dispersed ice with a higher extent. Not misleading, just different animals.

It misleading because extent does not tell the full story of what the ice looks like. 2019 had a marginally lower extent than 2016 but the ice pack was largely  more compact whilst 2016 ice pack was full of holes near the pole with true  open water reaching 85 degrees north in 2 areas. The only area that helped kept extent above 4 million was the Laptev sea but this ice was also quite diffused. If this year ice pack stays compact then I'll be surprised if we beat 2012 but if holes do start to develop then that would be a concern.

Pagophilus

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Re: The 2020 melting season
« Reply #2477 on: July 09, 2020, 04:38:19 PM »
Thanks once more, Aluminium

To my eye, your animation appears to show the ice pack edge on the Atlantic side starting to align obediently above the 200m submarine contour in this area, as is it often does.

Could be coincidental, and there is a lot of compaction going on, but much melt does happen from below...   As ever I am glad to be corrected and to learn...

July 4-8.

2019.
You may delay, but time will not.   Benjamin Franklin.

BornFromTheVoid

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Re: The 2020 melting season
« Reply #2478 on: July 09, 2020, 04:42:30 PM »
Latest version of the graph from yesterday. Following the extent loss of 3 of the last 20 years would put us below the 2012 minimum. Yesterday it was just 1. Animation from yesterday to delay is at the bottom.



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

gandul

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Re: The 2020 melting season
« Reply #2479 on: July 09, 2020, 05:09:14 PM »
I doubt melt pond draining explains the stall in area drop, as it would require incredibly simultaneous draining across the Arctic. A slow down in surface melting in the Pacific side of the CAB and Beaufort sea has also happened.

blumenkraft

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Re: The 2020 melting season
« Reply #2480 on: July 09, 2020, 05:42:58 PM »
Gandul, check this (by clicking). This is only one example in the CAA. I could do 100 of those.

BornFromTheVoid

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Re: The 2020 melting season
« Reply #2481 on: July 09, 2020, 06:32:21 PM »
NSIDC daily extent

11-day change is -1721
11-day average is -156

Has there ever been a series of numbers like this before? I'm too lazy to look through the historical data. I may load it all into a SQL database to run some queries.

2020-06-27  9.854
2020-06-28  9.723  -131
2020-06-29  9.575  -148
2020-06-30  9.445  -130
2020-07-01  9.262  -183
2020-07-02  9.142  -120
2020-07-03  8.942  -200
2020-07-04  8.807  -135
2020-07-05  8.648  -159
2020-07-06  8.455  -193
2020-07-07  8.276  -179
2020-07-08  8.133  -143


At 11, that appears to be the longest stretch of consecutive 100k losses. Next longest stretch seems to the the 8 days up to July 13th in 2011. A few occasions where a single day or two prevented longer streaks
I recently joined the twitter thing, where I post more analysis, pics and animations: @Icy_Samuel

gandul

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Re: The 2020 melting season
« Reply #2482 on: July 09, 2020, 06:47:00 PM »
Gandul, check this (by clicking). This is only one example in the CAA. I could do 100 of those.
Pretty convincing, as usual. Nice.

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Re: The 2020 melting season
« Reply #2483 on: July 09, 2020, 06:54:45 PM »
I'm not really convinced melting has really slowed down much. It's still warm with a fair amount of sun...I just think it has to do with how scattered the whole pack is. There are open sections of water in so many portions along with some significant melt ponds pretty much at the pole. If/when a strong low forms I think it's going to cause some destruction.
pls!

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Re: The 2020 melting season
« Reply #2484 on: July 09, 2020, 06:59:19 PM »
Sorry ..  having seen the loss of ice apparent in Aluminium's gif I was not ready to see a stall when in reality it was as bad a 4 day run as I've ever seen . And only a couple of days ago I was the one saying 'melt ponds' to Phoenix .. just today it did not compute .. massive ice loss recorded as a pause .. b.c.
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Aluminium

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Re: The 2020 melting season
« Reply #2485 on: July 09, 2020, 07:22:28 PM »
Despite of cooling in forecasts, t850 remains high. 4-8°С almost everywhere in the Arctic according to nullschool. Up to 20°C in the Barents Sea.

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Re: The 2020 melting season
« Reply #2486 on: July 09, 2020, 07:30:39 PM »
Take a look at this - it's quite remarkable. Last year, the mega crack which formed above the CAA/Greenland was quite profound and really speaks to how the pack was affected in what was once considered more of a 'safe' place for the older ice. So knowing that, just look at what's going on between Greenland and the CAA. I purposefully chose a date far in advance in 2019 to compare to today (7/9) to emphasize just how much the heat in that region has impacted the ice and also the extent to which changes are unfolding in that specific area.

As the pack rotates clockwise in the gyre, more ice is going to be pushed into warm water in the peripheral seas; in my opinion, what we are seeing here are the stresses the pack is under and how it fails to act as cohesive as it once did. That said, I'd love to hear others' opinions on this, but it most certainly piques my interest.
pls!

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Re: The 2020 melting season
« Reply #2487 on: July 09, 2020, 08:11:17 PM »
While extent continues to drop, area has actually stalled for the last 4 days. More draining melt ponds?

The JAXA AMSR2 melt graphics also show a reduction in surface melting in the last few days.  I guess the lack of warm air advection from lower latitudes is playing a role.



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Re: The 2020 melting season
« Reply #2488 on: July 09, 2020, 08:57:51 PM »
Long time lurker but this is my first post here.  The first of what I'm sure will be many questions:  This animation seems to show a lot of transport south through the Fram being driven by the GAA.  How does this compare with satellite era averages for the summer months?

update on buoy drift using iabp data for whoi itp buoys, apr-jul7

Phoenix

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Re: The 2020 melting season
« Reply #2489 on: July 09, 2020, 09:30:49 PM »
Let's assume that widespread simultaneous melt pond drainage explains the pause in area loss.

What should be the expectation for re-emergence of new melt ponds if we postulate that the melting forces are still at peak strength?

One expectation might be never. The cracks through which yesterdays melt ponds have drained might remain open and drainage will be constant w/o buildup of ponds of similar magnitude.

Another expectation might be that melt ponds will reappear after some short interval to regenerate.

A mixture of the two options is also possible.

What kind of information helps to distinguish between a genuine slowdown in melting and a statistical pause due primarily to drainage? If someone could point to evidence they would expect to see with a genuine slowdown, it makes it easier to differentiate between the two situations.
« Last Edit: July 10, 2020, 02:29:31 AM by oren »

blumenkraft

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Re: The 2020 melting season
« Reply #2490 on: July 09, 2020, 09:44:14 PM »
Hey, Gizmo. Nice to meet you. :)

That animation is showing a longer time period. All this movement is not caused by the GAAC, only the last few frames (if any).

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Re: The 2020 melting season
« Reply #2491 on: July 09, 2020, 09:45:37 PM »
This animation seems to show a lot of transport south through the Fram being driven by the GAA.  How does this compare with satellite era averages for the summer months?

Wipneus's regular updates in the PIOMAS model thread includes a graph of fram export volume with the seasonal average: https://forum.arctic-sea-ice.net/index.php/topic,119.msg271734.html#msg271734

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Re: The 2020 melting season
« Reply #2492 on: July 09, 2020, 10:28:26 PM »
This animation seems to show a lot of transport south through the Fram being driven by the GAA.  How does this compare with satellite era averages for the summer months?

Wipneus's regular updates in the PIOMAS model thread includes a graph of fram export volume with the seasonal average: https://forum.arctic-sea-ice.net/index.php/topic,119.msg271734.html#msg271734

Thanks, just what I was looking for. 

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Re: The 2020 melting season
« Reply #2493 on: July 09, 2020, 10:53:11 PM »
While extent continues to drop, area has actually stalled for the last 4 days. More draining melt ponds?

The JAXA AMSR2 melt graphics also show a reduction in surface melting in the last few days.  I guess the lack of warm air advection from lower latitudes is playing a role.




The sea ice concentration in the CAB on that picture dated 4/7 is so low because of melt ponding.. So when melt ponds drains, like Blumenkraft above showed they did on satellite pictures, naturally the concentration will be much higher.
I don't think this implies that there is significantly less surface ice melting..

gandul

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Re: The 2020 melting season
« Reply #2494 on: July 09, 2020, 11:18:22 PM »
Yeah, I still am not sold by the simultaneous “draining” in half the Arctic. What Steven shows is that extensive, with JAXA data this time, and SMOS data showed something similar.
The pacific side of the CAB and Beaufort sea probably are under surface melting slowdown. The area drop stall is the least bad outcome of this beast of anticyclone. There’s simply colder air in the pacific side of the anticyclone as compared to the Siberian seas and the Atlantic side.

SMOS shows a peak on surface melting around July 5, then a moderation inthe next three days. (Needs a click)

In any case the 12z ecmwf foresees a more dynamic high pressure staying over 1030 hPa until Monday, then sliding toward the Beaufort sea. Not good anyway.
« Last Edit: July 09, 2020, 11:40:25 PM by gandul »

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Re: The 2020 melting season
« Reply #2495 on: July 09, 2020, 11:24:05 PM »
X amount of heat does not produce Y amount of area loss.
X amount of heat produces Z amount of volume loss.
Daily area loss reflect how much thin ice melts in a day. A larger amount of thicker ice may melt and no melt ponds required to slow area loss.

GoSouthYoungins

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Re: The 2020 melting season
« Reply #2496 on: July 09, 2020, 11:42:53 PM »
big time oops

bbr2315

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Re: The 2020 melting season
« Reply #2497 on: July 09, 2020, 11:55:13 PM »
The extended pattern on the 12z EURO in the Arctic Basin is beginning to resemble the setup prior to the 2012 GAC at 500MB. It actually originates from the blob of cold air over the Beaufort around 48 hrs, which drifts towards the Chukchi / ESS and then begins to expand in scope by D10.



With so much open water sopping up so much insolation and massive heat advecting polewards both from the oceans and the continents I would be hard pressed to see a similar event as 2012 GAC *not* unfolding in 2020. I do believe conditions supportive of such an occurrence are beginning to foment in extended guidance.

It should be noted the polar low I mention at the beginning of this post is actually forecast to drop some snow on the highest mountains of the Mackenzie Ranges, and guidance is also beginning to get rather cold for much of Canada by D5-10. This will probably be temporary but it is interesting to see occur in sync with the Arctic anomalies. One other important note is that anecdotally, potent heat in the NE US is correlated with major heat into the CAB, and we are currently looking like we may see a major 594DM+ ridge develop over the US by the end of the extended range as well (at the same time as Canada gets a bit chilly).

I do believe the combination of these factors point to a potent melt period continuing for the foreseeable future, for a variety of reasons. While it is nice to see some hints of winter returning across the highest elevations of the continents, it is disturbing in that this cold should be in the Arctic, and one suspects that an early return of elevated snows in the high and mid-latitudes of the continents would be expedient in advecting even more massive amounts of accumulated oceanic heat into the poles by way of corresponding seasonal -500MB anomalies as we head into August, September, and October.

Case in point, D10 map -- yes I know it is extended, but it perfectly illustrates how cold is "wasted" in the continents on generating unsustainable snowcover (for the time being) which actually brings even more heat into the Arctic.


Michael Hauber

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Re: The 2020 melting season
« Reply #2498 on: July 10, 2020, 12:48:53 AM »
My guess is that the increase in concentration is due to changes in atmospheric conditions.  On the 5th much of the CAB was cloudy - presumably low warm fog, with a clear area towards Laptev.  The clear area moved into the CAB and cloudy conditions over the Laptev by the 9th, which very roughly corresponds to increases in sea ice concentration over the CAB and very slight reductions towards Laptev.

In the past it has been quite obvious to me that major cloud bands associated with low pressure systems correspond to temporary reductions in sea ice concentration picked up by sensors.  Have not noticed it with fog/low cloud under high pressure before though, and the connection currently is not totally convincing to me, but something to consider IMO.
Climate change:  Prepare for the worst, hope for the best, expect the middle.

romett1

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Re: The 2020 melting season
« Reply #2499 on: July 10, 2020, 03:24:23 AM »
18Z GFS - Browsing through July 19th - H 1033 still sitting there.