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HapHazard

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Re: The 2020 melting season
« Reply #5000 on: August 17, 2020, 08:22:30 PM »
I've long predicted this year would be exceptional, looks like it still will be.

(for me, that means being top 3 in at least 3 of the following 4 areas: extent, area, volume, eye test)

Freegrass

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Re: The 2020 melting season
« Reply #5001 on: August 17, 2020, 09:05:29 PM »
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Freegrass

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Re: The 2020 melting season
« Reply #5002 on: August 17, 2020, 09:12:32 PM »
I haven't been able to post recently cuz I had a new job working 60 to 70 hours a week.

Everything is looking towards a second lowest extent a record low volume and possibly a record-low area but it's going to be close
Congrats on the new job.

I'm still wondering how much melting is going to happen in the remaining few weeks, while there is still a lot of weak ice to melt, I wonder how much melting will get into the Central Arctic Sea, given A) that the ice above 85N will start to refreeze soon, B) August hasn't had much wind to move the ice around and bring it in contact with warmer saltier water C) the current windy forecasts that Freegrass has been posting show a bit of wind across the ESS and some going out the Fram?

GFS is showing a lot of wind on the Atlantic side about 8-10 days out, but that's not reliable, and wouldn't that be too late to make much of a difference anyway?
If you use the animation function on the Polar Portal (DMI) website, you can see that the ice is already getting thicker north of Laptev. What's causing this? Bad software, or compaction? It looks like compaction to me.

http://polarportal.dk/en/sea-ice-and-icebergs/sea-ice-thickness-and-volume/
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glennbuck

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Re: The 2020 melting season
« Reply #5003 on: August 17, 2020, 09:50:11 PM »

Following a comment by A-Team on the Mosaic thread, I have compiled temperature statistics for Cape Morris Jesup at the northernmost tip of Greenland, the border between the Lincoln Sea and the Wandel Sea. To my surprise, despite the whole region having the lowest summer ice cover in the satellite record, the temps have been just a bit high compared to the last ten years. 2012, 2016, 2019 and 2015 were all warmer.

I couldn't find a reasonable method to compare the wind statistics though.


Franz Josef Land, west coast and Svalbard south east coast, Arctic Ocean area, seems to of been hotter than most years on record in 2020, from looking back at past years 2014-2019 for July and August.
« Last Edit: August 17, 2020, 10:19:11 PM by glennbuck »

Steven

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Re: The 2020 melting season
« Reply #5004 on: August 17, 2020, 10:08:39 PM »
I've long predicted this year would be exceptional, looks like it still will be.

(for me, that means being top 3 in at least 3 of the following 4 areas: extent, area, volume, eye test)

A top 3 rank for the September minimum is not exceptional at all.  In fact, most years were "exceptional" by your definition.  Five of the last 10 years had a top 3 minimum for both extent, area and volume at the time.  And 16 of the last 30 years.

jdallen

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Re: The 2020 melting season
« Reply #5005 on: August 17, 2020, 10:24:11 PM »
I haven't been able to post recently cuz I had a new job working 60 to 70 hours a week.
Everything is looking towards a second lowest extent a record low volume and possibly a record-low area but it's going to be close
<snip>
I'm still wondering how much melting is going to happen in the remaining few weeks, while there is still a lot of weak ice to melt, I wonder how much melting will get into the Central Arctic Sea, given A) that the ice above 85N will start to refreeze soon, B) <snip>
<snip>
Congratulations, Friv!

I think if you look at the purple in the attached Bremen image we have a reasonable preview of what the season's final extent will look like.

There will continue to be bottom melt in the CAB for some time to come, and there isn't really a lot of open water north of 85 right now.  With a storm and compaction, we may yet see part of the Atlantic side edge retreat north of 85 in spite of cooler temperatures.  In summary, what happens north of 85 won't provide a significant contribution to the end of season statistics.

The action really is on the Pacific side, which lies below 80N, and on the Atlantic margin from Svalbard around to the Laptev, where incoming weather may cause further inroads into extent.

(edit: oops, forgot the graphic.  Now attached.)
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jdallen

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Re: The 2020 melting season
« Reply #5006 on: August 17, 2020, 10:39:18 PM »
My daily browse through EOSDIS came across this image of Ellesmere and environs.

The open water visible here is quite striking!
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Re: The 2020 melting season
« Reply #5007 on: August 17, 2020, 10:49:25 PM »
Not sure if it just my system, but Corrective Reflectance 7,2,1 doesn't seem to open up past the East Greenland coast, today.

Data from Aqua seems to have gone missing for the last couple of days, so it's my system as well! However Terra, Suomi and NOAA-20 are all still available
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HapHazard

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Re: The 2020 melting season
« Reply #5008 on: August 17, 2020, 10:54:35 PM »
I've long predicted this year would be exceptional, looks like it still will be.

(for me, that means being top 3 in at least 3 of the following 4 areas: extent, area, volume, eye test)

A top 3 rank for the September minimum is not exceptional at all.  In fact, most years were "exceptional" by your definition.  Five of the last 10 years had a top 3 minimum for both extent, area and volume at the time.  And 16 of the last 30 years.
We live in exceptional times. Pretty crazy. Perhaps I'll go with top 2 then.
« Last Edit: August 17, 2020, 11:11:24 PM by HapHazard »

FishOutofWater

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Re: The 2020 melting season
« Reply #5009 on: August 17, 2020, 11:11:39 PM »
Mercator ocean shows a current at 100m running through the Nares strait and wrapping around the north coast of Greenland. The Coriolis effect turns currents with a northwards component to the right in the NH so the current is very likely a warm current running northeastwards through the Nares strait which then keeps turning right along the continental shelf of northern Greenland. The current maps for 30m and 0m show eddies, complexity and directional ambiguity but I'm confident that there has been some upwelling in areas where the ice has been transported away from the coast.
I very much doubt that there is a warm current flowing north through the Nares strait. There is a tidal current in the Nares, but the general flow is of cold water going south. See this paper for more details, "Propagation and Vertical Structure of the Tidal Flow in Nares Strait".

There is apparently a current flowing from the mouth of the Nares north-east along the Greenland coast. I have suggested that this is the northward pulse of the tidal current, similar to what I have experienced alongt he coast of Sicily south of the Messina strait, a narrow and periodic, but at times surprisingly vigorous, current.
I am currently reading a paper from 2015 link. Random extracts attached..
My take on it..
Ice Arches matter - none this year?
The main current is heading south, at the western edge when there is landfast ice, on the centreline when ice is mobile or non-existent..
A narrow current heads north.

With global heating+arctic amplification say goodbye to landfast ice for longer periods of the year?

But much better for people who know what they are talking about to comment.

https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2015JC011091
Modeled ocean circulation in Nares Strait and its dependence on landfast‐ice cover

Quote

Ice conditions typically alternate between landfast and mobile states that are associated with the formation and breakdown of ice arches across Smith Sound and northern Robeson Channel [Kwok et al., 2010]. In years in which neither ice arch forms, such as 2007, ice fluxes roughly 2–3 times those of a typical year have been inferred [Kwok et al., 2010] and modeled [Rasmussen et al., 2010].

The multiyear Canadian Archipelago Throughflow Study [CATS; Münchow and Melling, 2008] maintained a mooring array across southern Kennedy Channel (roughly 80.5°N, Figure 1) from 2003 to 2012.

In the annual mean, flow across most of Kennedy Channel is southward with a vertically averaged magnitude of about 7 cm s−1 on the western side of the channel. On the eastern edge of the channel (south of Franklin Island located at 80.8°N, 66.5°W), a narrow current heads to the north with a depth mean of roughly 4 cm s−1. Rabe et al. [2012] showed that the mean structure of the main southward current is markedly different under landfast and mobile ice conditions, with important implications for seasonal and interannual variability of freshwater transport through the strait.

I am very aware that the mean flow is down the Nares strait. We had an extended period this summer when ice did not flow down the strait and katabatic winds blew off the ice plateau of Greenland down to the north coast and offshore for hundreds of miles into the Arctic. Those offshore winds pushed the ice towards the pole, opening up the large, anomalous area of open water. Direct offshore southerly winds induce a long shore current from west to east on the north shore of Greenland due to the way the Coriolis effect. Winds blew up the Fram strait on offshore along the coast of Greenland enhancing the flow of the normally narrow current, extending it up the north shore of Greenland at the 100m level. That's how I'm interpreting the map based on the weather and the flow of ice at the surface.

When water moves in directions against the Coriolis effect it forms loops, gyres and eddies if it isn't forced through a channel. That may be happening around northern Greenland at the surface to 30m depth levels as shown on the Mercator maps.

I know my interpretation needs more data to support it, but it would help explain the very unusual ice movements and loss of ice north of Greenland.

Added info see -
https://www.nature.com/scitable/knowledge/library/arctic-ocean-circulation-going-around-at-the-102811553/

Water flowing on the NW coast of Greenland may be Atlantic water that flowed back from Siberia along the Lomonosov ridge that is heading back out the Fram strait. That water might be involved in near surface eddies  I suspect that more research is needed to understand what we have been watching on the north coast of Greenland the past 6 weeks. The lack of ice from the N coast Greenland to the pole we have been observing is not normal. In normal years ice piles up there. Something is likely different below the sea surface as well.

Note that surface eddies can drive a subsurface current in the opposite direction to the movement of the surface eddies. This has been observed in the south Atlantic in the northwards eddy movement from the tip of South Africa. There's an undercurrent moving towards South Africa. I suspect that the situation on the north slope of Greenland is complicated and the loss of ice shelves is related to warm water coming up from below. The loss of these shelves is going to change the behavior of the whole Arctic system as ice moves more freely around the Arctic and upwelling and downwelling along continental shelf slopes is enhanced. And I think it is enhancing the melting of sea ice this summer. The vector winds (see below) this July were not normal and must have affected the ocean currents.
« Last Edit: August 18, 2020, 12:51:22 AM by FishOutofWater »

oren

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Re: The 2020 melting season
« Reply #5010 on: August 17, 2020, 11:57:36 PM »
Friv, congrats on the new job.

Quote
If you use the animation function on the Polar Portal (DMI) website, you can see that the ice is already getting thicker north of Laptev. What's causing this? Bad software, or compaction? It looks like compaction to me.
FG, the simple explanation is that DMI is simply wrong. No way that ice is thickening at this time of year. The model is not reliable. We can discuss it further in the DMI thread.

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Re: The 2020 melting season
« Reply #5011 on: August 18, 2020, 02:52:55 AM »
Another HYCOM prediction. Looks like thicker ice is going to vacation to Beaufort Sea  :D

Michael Hauber

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Re: The 2020 melting season
« Reply #5012 on: August 18, 2020, 03:08:58 AM »
I would guess the slow down is pretty much over, and by the stats it is exceptional.  I have gathered statistics on the other significant slow downs since 2007 during peak melting season (June to late August).  This year had the highest rate before slowdown, the second slowest rate after slowdown, a relatively large range of days for both periods.  And when measured as a number of standard deviations away from average, both periods exceptional at well over 2 standard deviations away from average.

As a very simple metric, add the two standard deviations together, to get the attached chart.

2020 Jun 28 to Jul 22, 127,657/day, 2.60 stdev above average
2020 Jul 23 to Aug 13, 45,238/day, 2.45 stdev below average

2014 Jun 18 to Jul 17, 96,460/day, 0.72 stdev above average
2014 Jul 18 to Jul 25, 40,355/day, 1.88 std dev below average

2013 Jun 24 to Jul 22, 112,316/day, 1.73 st dev above average
2013 Jul 23 to Aug 2, 50,023/day, 1.72 std dev below average

2011 Jul 1 to Jul 18 114,548/day, 1.33 std dev above average
2011 Jul 19 to Aug 3 49,780/day, 1.99 std dev below average

2010 Jun 15 to Jun 28 97,131/day 1.86 std dev above average
2010 Jun 29 to Jul 15 57,322/day 2.08 std dev below average

2009 Jul 13 to Jul 28 110,608/day 1.46 std dev above average
2009 Jul 29 to Aug 12 48,697/day 1.79 std dev below average
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Re: The 2020 melting season
« Reply #5013 on: August 18, 2020, 03:12:25 AM »
Another HYCOM prediction. Looks like thicker ice is going to vacation to Beaufort Sea  :D

I wonder how far that thick section will be able to rotate. Is it possible that it could continue to move even further clockwise and eventually end up in the Chuchki or even fully reach the Siberian side over the next few seasons?

GoSouthYoungins

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Re: The 2020 melting season
« Reply #5014 on: August 18, 2020, 04:09:48 AM »
Another HYCOM prediction. Looks like thicker ice is going to vacation to Beaufort Sea  :D

I wonder how far that thick section will be able to rotate. Is it possible that it could continue to move even further clockwise and eventually end up in the Chuchki or even fully reach the Siberian side over the next few seasons?

Next few seasons...

pretty wishful.
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Re: The 2020 melting season
« Reply #5015 on: August 18, 2020, 05:24:19 AM »
Slowly but steady the Pacific side is vanishing.


Very low Beaufort concentration while the chuckchi is gone
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Re: The 2020 melting season
« Reply #5016 on: August 18, 2020, 06:30:04 AM »
I very much doubt that there is a warm current flowing north through the Nares strait.
I am currently reading a paper from 2015 link. Random extracts attached..
My take on it..
A narrow northflowing current, interesting. They didn't find it in the other paper. But is it a warm current as FooW thinks he sees?

But a small northflowing current could explain the movement that is seen towards the norht-east along the coast of Greenland, so no tidal current is  needed to explain at least some of the motion seen there.
« Last Edit: August 18, 2020, 06:52:18 AM by binntho »
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binntho

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Re: The 2020 melting season
« Reply #5017 on: August 18, 2020, 06:44:02 AM »
Something is likely different below the sea surface as well.
Possibly, but not at all necessary and no reason to invent new currents to explain what can be easily explained, as Oren points out, by the unusual weather this summer. And of course, the ever-thinner and more mobile ice as a result of AGW is presumably a major factor.
 
A-Team posted on the MOSAIC forum about the NEW polynya which is the one currently extending it's fingers to the north-east of Greenland.

His post corrected one of my many misconceptions, i.e. that the NEW was caused by upwelling of warm water. But the most interesting take-away, for me, was the fact that in the area where the NEW traditionally forms during early spring,  tidal movements could play a large part if they existed at all. Which they apparently don't.

See this paper, "North East Water polynya (Greenland Sea)"  for a very interesting description of how a cold surface layer and a warm deeper layer do not mix at all, even if the Belgica banks and it's surrounding troughs are the archetypical tidal playground.

That is, it would be if there was any significant tidal movement at all in the Fram strait, which there isn't.
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ajouis

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Re: The 2020 melting season
« Reply #5018 on: August 18, 2020, 07:40:00 AM »
Another HYCOM prediction. Looks like thicker ice is going to vacation to Beaufort Sea  :D
Pretty interesting that it predicts both the kara and the greenland sea ice to go poof, although it will be almost certainly untrue for the latter with gusts of over 100 km/h from the 24th turbo driving exports, I think it is missing on the Beaufort disintegration though, it’s looking as ready as the greenland sea ice in places I would say
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Re: The 2020 melting season
« Reply #5019 on: August 18, 2020, 08:38:07 AM »
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Re: The 2020 melting season
« Reply #5020 on: August 18, 2020, 09:58:08 AM »
Change from 16th to 17th

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

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Re: The 2020 melting season
« Reply #5021 on: August 18, 2020, 01:46:14 PM »
mercator 30m salinity weekly from 06:07
« Last Edit: August 18, 2020, 02:10:36 PM by johnm33 »

Freegrass

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Re: The 2020 melting season
« Reply #5022 on: August 18, 2020, 02:08:51 PM »
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Re: The 2020 melting season
« Reply #5023 on: August 18, 2020, 02:19:18 PM »
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Re: The 2020 melting season
« Reply #5024 on: August 18, 2020, 02:21:22 PM »
I very much doubt that there is a warm current flowing north through the Nares strait.
I am currently reading a paper from 2015 link. Random extracts attached..
My take on it..
A narrow northflowing current, interesting. They didn't find it in the other paper. But is it a warm current as FooW thinks he sees?

But a small northflowing current could explain the movement that is seen towards the norht-east along the coast of Greenland, so no tidal current is  needed to explain at least some of the motion seen there.
They found it through measurments taken by "The multiyear Canadian Archipelago Throughflow Study [CATS; Münchow and Melling, 2008] maintained a mooring array across southern Kennedy Channel (roughly 80.5°N, Figure 1) from 2003 to 2012."

So it's real data - but 2012 was 8 years ago.

The paper also talked about how much of the southward flow through the Nares Strait from the Lincoln Sea is due to sea-level height variation.
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Re: The 2020 melting season
« Reply #5025 on: August 18, 2020, 02:35:56 PM »
I am impressed by the slow but relentless progress of the sea ice edge towards 85 North along the Atlantic Front, despite the ice being pretty much at 100% concentration.
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Re: The 2020 melting season
« Reply #5026 on: August 18, 2020, 02:36:31 PM »
They found it through measurments taken by "The multiyear Canadian Archipelago Throughflow Study [CATS; Münchow and Melling, 2008] maintained a mooring array across southern Kennedy Channel (roughly 80.5°N, Figure 1) from 2003 to 2012."

I never doubted their findings. But it's funny, the paper I linked used a long‐term monitoring array deployed across Nares Strait between 2003 and 2009

In spite of the difference in years I suspect they are talking about the same array. But focusing on different things, hence different findings that are not mutually exclusive.

Quote
The paper also talked about how much of the southward flow through the Nares Strait from the Lincoln Sea is due to sea-level height variation.

Isn't the main reason for the difference in sea level due to the accumulation of a fresh-water lens under the Arctic ice? This accumulation can apparently continue for years until a change in weather patterns leads to it being discharged. I seem to remember there being talk of this fresh-water lens being unusally "full" at the moment, with large amounts of fresh water ready to spill out into surrounding seas. Makes you wander how everything can fit into the same ocean - the known currents, the halocline and thermocline and the fresh-water lens, and then add to that the various currents, flows, forcings and turbulences that some people think they see or imagine.
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Re: The 2020 melting season
« Reply #5027 on: August 18, 2020, 02:39:39 PM »
I am impressed by the slow but relentless progress of the sea ice edge towards 85 North along the Atlantic Front, despite the ice being pretty much at 100% concentration.

I was thinking the same thing. Look at BFTV's one day change at 5021 above and imagine 10 or 20 more days of that.

Freegrass

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Re: The 2020 melting season
« Reply #5028 on: August 18, 2020, 03:20:28 PM »
I am impressed by the slow but relentless progress of the sea ice edge towards 85 North along the Atlantic Front, despite the ice being pretty much at 100% concentration.
Is it possible that some of that may be rain?

GIF starts @ 2020-08-15 00:00 UTC
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Re: The 2020 melting season
« Reply #5029 on: August 18, 2020, 03:31:51 PM »
With the latest projection based on the previous 20 years, none produce a minimum below 2012. The average melt rate would place 2020 at 2nd lowest, while the slowest melt would result in 5th lowest. 12/20 produce the 2nd lowest minimum on record.
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Re: The 2020 melting season
« Reply #5030 on: August 18, 2020, 03:51:23 PM »
I am impressed by the slow but relentless progress of the sea ice edge towards 85 North along the Atlantic Front, despite the ice being pretty much at 100% concentration.
The Nansen shelf break provides a handy static line to watch the ice edge retreat along the atl front. Other points of interest are the bathymetry north of Greenland and the yermak and chukchi plateaux.
Here using the development version of awi amsr2 overlaid onto gmrt bathymetry at 80% transparent. Open water has been set to fully transparent.
Scaling slightly out. Have to work on the number of colours used for gifs
Large file 9MB

bbr2315

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Re: The 2020 melting season
« Reply #5031 on: August 18, 2020, 04:27:34 PM »
As the ATL front thins and disperses it is at the intersection of several major forces. The latest HYCOM and EURO both suggest, IMO, there is some possibility that as the FYI melts out, the ATL pack may actually fracture from the main icepack. It looks, again -- to my eyes -- like the Lomonosov Ridge might be the "sloughing" point for the sea ice / this division point. If such an event would occur it would actually triple the Atlantic melt front.... (the current front is 1X, if the ice breaks off from the main pack you now have 2X the front in the ice that is now removed from the pack PLUS an entirely new additional ice front where the ice rips in two against the main pack itself -- apologies if this language is a bit convoluted).

Such an event would be ideal for resolving +OHC / accumulated insolation however it will come at the expense of a huge chunk of the CAB, and if this occurs it could also be severely disruptive to the halocline.



The ice that is going to possibly slough off is centered on the thicker ice N of FJL... and the dispersion / melt point in the Laptev is looking like it might want to meet up with the one forming in the Lincoln Sea soon....



After illustrating the breakdown of what may be the new melt front I would conclude that if it does occur it is because we are running out of ice to export as it is possible that both of the ice fronts that open up actually involve ice moving in the same direction (counterintuitively)....

It is like the ATL front is unzipping so fast that a new zipper is opening behind the front lines bc the reinforcements (ice) cannot keep up w the heat.

This post was IMO rather prescient and shows why the ATL is now engaging in an apparent rapid retreat. There has been a melt front behind the main one but it has been mostly happening underneath (IMO). Now that volume is approaching 0 the surface is also disappearing as much of this ice is rather thick.

Modeling portends a continued dramatic retreat of the ATL front. I would also anticipate the surplus +OHC in Laptev and Kara partially resolving in a major cyclonic event within the next few weeks.

We are likely to see some major extent drops in the next few days and weeks as the borderline ice in the Beaufort / Chukchi melts out en-masse and the ATL front continues its major retreat.

The outline of Lomonosov Ridge is slightly apparent in the 8/1 Bremen image and very apparent in the 8/17 image. I wonder how much on the ATL side of the ridge will melt out // it could be almost all of the ice....

Alphabet Hotel

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Re: The 2020 melting season
« Reply #5032 on: August 18, 2020, 05:47:25 PM »
9-day AMSR2 high-res false color animation. This format seems unsuited to animating, but I'll post it anyway. I may not do more.

large unoptimized GIF file. click to animate.

F.Tnioli

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Re: The 2020 melting season
« Reply #5033 on: August 18, 2020, 06:24:19 PM »
I've long predicted this year would be exceptional, looks like it still will be.

(for me, that means being top 3 in at least 3 of the following 4 areas: extent, area, volume, eye test)

A top 3 rank for the September minimum is not exceptional at all.  In fact, most years were "exceptional" by your definition.  Five of the last 10 years had a top 3 minimum for both extent, area and volume at the time.  And 16 of the last 30 years.
We live in exceptional times. Pretty crazy. Perhaps I'll go with top 2 then.
Stick with top 3, i say. Steven here is dead wrong in his take about what exceptional means. To him, exceptional becomes normal if most of things are exceptional. But it's logical failure. Exceptional things remain exceptional no matter how many of them there are. Exceptional is not a measure of probability, even though people often use it that way; but, "uncommon", "rare" etc as opposied to "common" - are the terms for that. Exceptionality, rather, is the word for something which is highly noteworthy, remarkable, significant, important. And in thise sense, sure thing, 16 out of the last 30 years, if not more, are indeed very exceptional.
To everyone: before posting in a melting season topic, please be sure to know contents of this moderator's post: https://forum.arctic-sea-ice.net/index.php/topic,3017.msg261893.html#msg261893 . Thanks!

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Re: The 2020 melting season
« Reply #5034 on: August 18, 2020, 06:32:34 PM »
Just looking at the latest GFS forecast, I bet Jaxa extent is under 4 mill km2 before the first of September

grixm

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Re: The 2020 melting season
« Reply #5035 on: August 18, 2020, 07:35:36 PM »
While the DMI 80 temperature has usually dipped below freezing at this point, we're still chugging away above that, this year.

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Re: The 2020 melting season
« Reply #5036 on: August 18, 2020, 08:32:51 PM »
Latest Five Day Forecast
Wind @ Surface + Total Precipitable Water
Large GiF!
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Re: The 2020 melting season
« Reply #5037 on: August 18, 2020, 08:41:50 PM »
Latest Five Day Forecast

Looks like towards the end there (23rd) things pick up a bit.  Some good winds (~45 km/h) going ENE off the CAA and NE Greenland.  Interesting to see how it affects the crack and melt in that area.


Freegrass

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Re: The 2020 melting season
« Reply #5038 on: August 18, 2020, 10:04:14 PM »
Latest Five Day Forecast

Looks like towards the end there (23rd) things pick up a bit.  Some good winds (~45 km/h) going ENE off the CAA and NE Greenland.  Interesting to see how it affects the crack and melt in that area.
So true. Tomorrow's forecast will start to get interesting. We'll have to wait and see how things will develop, but at the moment it's not looking good for the ice.

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Re: The 2020 melting season
« Reply #5039 on: August 18, 2020, 10:14:34 PM »
The EC 12z gets worse, a nice continuous push of warm, compacting winds over the Beaufort and Chukchi and a squeeze from the Atlantic side too, pushing MYI against Greenland and CAA...

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Re: The 2020 melting season
« Reply #5040 on: August 18, 2020, 10:27:02 PM »
I am impressed by the slow but relentless progress of the sea ice edge towards 85 North along the Atlantic Front, despite the ice being pretty much at 100% concentration.
The Nansen shelf break provides a handy static line to watch the ice edge retreat along the atl front. Other points of interest are the bathymetry north of Greenland and the yermak and chukchi plateaux.
Here using the development version of awi amsr2 overlaid onto gmrt bathymetry at 80% transparent. Open water has been set to fully transparent.
Scaling slightly out. Have to work on the number of colours used for gifs
Large file 9MB
Now that's a classy gif...
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Re: The 2020 melting season
« Reply #5041 on: August 18, 2020, 10:35:43 PM »
There is actually quite a bit of ice extant in Foxe Basin still. It will be curious to see if any portion survives into next winter, at this point with that amount I think it is very possible if not likely?

A-Team

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Re: The 2020 melting season
« Reply #5042 on: August 19, 2020, 04:09:39 AM »
Quote
ice left in Foxe Basin
Hudson Bay is entirely below the Arctic Circle and Foxe Basin just above so there's plenty of insolation left this season (see albedo calculator above). The air temperatures are quite mild currently so presumably the relic ice was thicker to begin with, floating in a cold pool, or protected from wind and collisional abrasion by proximity to land.

The melting/freezing course is probably best studied by concentration palette occupancy via the newly refined AMSR2_AWI time series. The first image below finds all the residual floes at high latitude, including the isolated by persistent ice behind Severnaya Zemlya studied by Oren above. This image needs a click to display at scale.

The latter two images zoom in on one of the larger pieces of lasting ice, showing it is mostly comprised of low concentration ice. A trend cannot be established from this single August 17th baseline image.

These images are made possible by the pixel-perfect undithered construction of the AWI high resolution product. Selecting land and open water with the non-contig color picker set at radius zero, followed by selection inverse, pink coloring, and removal of the central ice pack with the contiguous color picker, followed by fill with black, leaving only the outliers. Small amounts of ice indicated along many parts of the coast, fjords and rivers may or may not be authentic. The ice region under consideration is picked one pixel at a time and co-picked automatically in the embedded palette. Alternatively the small area could be excised and its histogram occupancy determined over in ImageJ as Uniquorn is doing Arctic wide on the AMSR2 forum.
« Last Edit: August 19, 2020, 04:20:13 AM by A-Team »

oren

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Re: The 2020 melting season
« Reply #5043 on: August 19, 2020, 04:16:45 AM »
There is actually quite a bit of ice extant in Foxe Basin still. It will be curious to see if any portion survives into next winter, at this point with that amount I think it is very possible if not likely?
As Neven likes to say, compare compare compare. A simple comparison with other years indicates that the likelihood is very low. Foxe Basin often has significant ice on this date, but very little if at all by early September.
Working on an animation, will upload when finished.

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Re: The 2020 melting season
« Reply #5044 on: August 19, 2020, 04:18:15 AM »
Might be spread out OVER A FEW DAYS...

but JAXA IS SHOWING HUGE FREAKING HUGE LOSSES ON THE CONCENTRATION GRAPHIC
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Re: The 2020 melting season
« Reply #5045 on: August 19, 2020, 04:47:14 AM »
Can you post some images showing what you mean, Friv? Is it the AMSR2 gallery or something else?

Frivolousz21

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Re: The 2020 melting season
« Reply #5046 on: August 19, 2020, 05:11:13 AM »
Hopefully this works

Looks like it's playing catch-up to the Bremen version over the Pacific side.
Click to animate
I got a nickname for all my guns
a Desert Eagle that I call Big Pun
a two shot that I call Tupac
and a dirty pistol that love to crew hop
my TEC 9 Imma call T-Pain
my 3-8 snub Imma call Lil Wayne
machine gun named Missy so loud
it go e-e-e-e-ow e-e-e-e-e-e-blaow

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Re: The 2020 melting season
« Reply #5047 on: August 19, 2020, 05:20:58 AM »
Here is the descending version.



Pretty big opening over the Pacific side
I got a nickname for all my guns
a Desert Eagle that I call Big Pun
a two shot that I call Tupac
and a dirty pistol that love to crew hop
my TEC 9 Imma call T-Pain
my 3-8 snub Imma call Lil Wayne
machine gun named Missy so loud
it go e-e-e-e-ow e-e-e-e-e-e-blaow

Frivolousz21

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Re: The 2020 melting season
« Reply #5048 on: August 19, 2020, 05:39:30 AM »
Another century drop on jaxa.

Tomorrow might be quite a bit larger drop
I got a nickname for all my guns
a Desert Eagle that I call Big Pun
a two shot that I call Tupac
and a dirty pistol that love to crew hop
my TEC 9 Imma call T-Pain
my 3-8 snub Imma call Lil Wayne
machine gun named Missy so loud
it go e-e-e-e-ow e-e-e-e-e-e-blaow

oren

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Re: The 2020 melting season
« Reply #5049 on: August 19, 2020, 05:41:26 AM »
Here is an animation of Foxe Basin from mid-August until final clearout, for 2011-2016 and 2018. 2020 is shown at the end. The ice in Foxe Basin persists a long time but is gone by mid-September, 2018 was the sole exception and cleared by Sep 23rd. 2019 was the sole contrarian exception, already clear by mid-Aug.

Click to animate, large file. Note the biggest challenge is to find cloud-free days.
« Last Edit: August 19, 2020, 05:47:03 AM by oren »