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stjuuv

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Re: The 2020 melting season
« Reply #5900 on: September 06, 2020, 10:16:26 PM »
Snow will indeed increase (marginally) but eventually this will transition to rainfall
Amazing graphic, may I ask where it is from?
https://www.nature.com/articles/s41598-018-34450-3

SimonF92

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Re: The 2020 melting season
« Reply #5901 on: September 06, 2020, 10:33:15 PM »
Thanks stjuuv, i should have provided a link!
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OffTheGrid

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Re: The 2020 melting season
« Reply #5902 on: September 06, 2020, 11:19:32 PM »
Wind @ Surface + 3-hour Precipitation Accumulation for the last 72 hours and the next five days.

All that snow is gonna insulate the ice from freezing, isn't it? Will this become another positive feedback loop? More open water means more snow, means more open water and even more snow next year?
Probably not enough snow on the polar ice to matter much with insulating these days. But it may in Future years. It does nucleate ice cover that prevents heat loss and fresh water freezing on top releases latent heat to the floe that feeds bottom melt well after the surface is frozen. Especially if Its vapour thats condensing and freezing, which is more mass of water than the rain often.
Mostly Its rain so far. Though gfs is showing half the wind that Mosaic is right now, which probably means more rain too.

gandul

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Re: The 2020 melting season
« Reply #5903 on: September 06, 2020, 11:37:31 PM »
Wind @ Surface + 3-hour Precipitation Accumulation for the last 72 hours and the next five days.

All that snow is gonna insulate the ice from freezing, isn't it? Will this become another positive feedback loop? More open water means more snow, means more open water and even more snow next year?
Not necessarily. Overabundance of snow accumulation until sprint (50 cm or more) is also a melting season quencher and a wonderful negative feedback (‘13 ‘14 post 2012 and ‘17 post 2016, iirc).
The snow insulation effect works both ways, and snow is a wonderful reflector persisting perhaps until July.

So this winter let it snow, let it snow, let it snow, and we won’t need to worry for 2021.

Freegrass

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Re: The 2020 melting season
« Reply #5904 on: September 07, 2020, 01:52:26 AM »
Latest Five Day Forecast
Wind @ Surface + Total Precipitable Water
Large GiF!
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Freegrass

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Re: The 2020 melting season
« Reply #5905 on: September 07, 2020, 02:21:25 AM »
Snow will indeed increase (marginally) but eventually this will transition to rainfall
Amazing graphic, may I ask where it is from?
https://www.nature.com/articles/s41598-018-34450-3
Thank you all for the replies! Like the paper says: The relation between changes in Arctic rainfall and both temperature and precipitation is surprisingly complex. So the question I asked is probably one the most challenging to answer? I guess that in the end the logic remains the same; that more Arctic heat will translate to more melt, and that precipitation just makes predictions that much harder to make?
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Pagophilus

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Re: The 2020 melting season
« Reply #5906 on: September 07, 2020, 03:32:53 AM »
What I'm finding almost speechless is just how far back the ice edge has got as even only as far back as June, there was no real sign we will see Atlantification as much as we have seen. Yes, winds has been blowing in from the south fairly frequently but surely warm SSTS are playing their part aswell?
I agree that SSTS are crucial.  The unusually high specific heat of liquid water ensures that.  And BFTW's latest animation above (a deep bow to BFTW here) shows us how uniform the erosion of the ice has been around its margins (with the exception of a few parts of the Pacific side).  Warmer water will 'eat' at the edge of the ice, until equilibrium is reached...  This season, with the extraordinary warmth on the Siberian side, that could take a bit longer than expected.
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oren

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Re: The 2020 melting season
« Reply #5907 on: September 07, 2020, 03:33:33 AM »
Sentinel-1 animation of the Lincoln Sea. Nares Strait export has renewed since Aug 29th, with one of the large floes sloshing around for the last two months about to go out the door.

Click.

Freegrass

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Re: The 2020 melting season
« Reply #5908 on: September 07, 2020, 05:59:45 AM »
Sentinel-1 animation of the Lincoln Sea. Nares Strait export has renewed since Aug 29th, with one of the large floes sloshing around for the last two months about to go out the door.

Click.
That biggest floe has been lingering in that same area forever now. I think the arctic should start asking it rent...  ::)
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Aluminium

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Re: The 2020 melting season
« Reply #5909 on: September 07, 2020, 06:03:00 AM »
September 2-6.

2019.

Freegrass

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Re: The 2020 melting season
« Reply #5910 on: September 07, 2020, 06:07:01 AM »
DMI 80N now dropping like a rock. But look how long the melting season lasted... A new normal?
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VeliAlbertKallio

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Re: The 2020 melting season
« Reply #5911 on: September 07, 2020, 08:32:50 AM »
If the snow cover were as good negative feedback, then Ewing-Donne lake snow would rule also on land: the climate would progressively cool and end up in the ice ages. That didn't happen, snow is not driver for cooling but a respondent (although on land decomposition of biomaterials is a fundamental difference). Sea ice without snow leaks heat out best and thickens for the following summer as a result. Any cooling effect is volatile and biased towards onset of the spring rather than end of season.

Wind @ Surface + 3-hour Precipitation Accumulation for the last 72 hours and the next five days.

All that snow is gonna insulate the ice from freezing, isn't it? Will this become another positive feedback loop? More open water means more snow, means more open water and even more snow next year?
Not necessarily. Overabundance of snow accumulation until sprint (50 cm or more) is also a melting season quencher and a wonderful negative feedback (‘13 ‘14 post 2012 and ‘17 post 2016, iirc).
The snow insulation effect works both ways, and snow is a wonderful reflector persisting perhaps until July.

So this winter let it snow, let it snow, let it snow, and we won’t need to worry for 2021.
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Iain

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Re: The 2020 melting season
« Reply #5912 on: September 07, 2020, 09:18:28 AM »
The Jaxa downtime window has lengthened to 04h00 BST on the 10th:

ADS_NIPR
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Arctic Data archive System (ADS) will be unavailable due to the planned system maintenance.
We are sorry for the inconvenience this may cause.
<Maintenance window>
7 Sep. 2020 at 12:00JST  -  10 Sep. at 12:00 JST
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BornFromTheVoid

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Re: The 2020 melting season
« Reply #5913 on: September 07, 2020, 11:10:28 AM »
Latest images an animation.
I recently joined the twitter thing, where I post more analysis, pics and animations: @Icy_Samuel

Neven

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Re: The 2020 melting season
« Reply #5914 on: September 07, 2020, 11:41:48 AM »
DMI 80N now dropping like a rock. But look how long the melting season lasted... A new normal?

A new abnormal:)
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SimonF92

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Re: The 2020 melting season
« Reply #5915 on: September 07, 2020, 01:19:55 PM »
Water between floes beginning to freeze north of Ellef Rignes island
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aslan

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Re: The 2020 melting season
« Reply #5916 on: September 07, 2020, 01:34:22 PM »
In the Arctic basin, even a 8 to 10 seconds wave period is significant.

Unusual certainly, but not necessarily "significant". See just above.


For one part, forecast is worsening. Now, waves are forecasted to reach an height of up to 3 - 4 meters and a period of up to 08 - 09 seconds. Which is no surprise.

But anyway these waves are going to occur at the edge of an already weakened ice pack, and be orthogonal to the ice edge in Beaufort sea. And up to now such strong waves had consequences, so I do not see why this will not be the case today and tomorrow. And if we really want to argue over details, it is not swell but wind waves. Perhaps it is difficult to fully appreciate the consequences of this low. I do not want to forecast exact consequences of this cyclone in terms of the size of the floes break up or of upwelling, or etc... But for one part a low level jet at 30 – 35 knots with a sea state in consequence (Beaufort 6 – 7 in a word) is unusual at this time of year. It is the Arctic, not Hawaii. And on top of that, I really don’t see how this is going to just be unusual and not be significant. The arm of sea ice in Beaufort is probably going to loss ice again.

Freegrass

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Re: The 2020 melting season
« Reply #5917 on: September 07, 2020, 02:02:53 PM »
Latest Five Day Forecast
Wind @ Surface
Wind + Temp @ 850hPa
Wind @ 250hPa
Large GiFS!

This storm seems to have strengthened again. Basically the 5 day old forecast was right.  :-\
« Last Edit: September 07, 2020, 02:25:10 PM by Freegrass »
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Tom_Mazanec

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Re: The 2020 melting season
« Reply #5918 on: September 07, 2020, 02:07:42 PM »
So Peak Snow is about 2035.
« Last Edit: September 07, 2020, 03:40:19 PM by Tom_Mazanec »
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gerontocrat

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Re: The 2020 melting season
« Reply #5920 on: September 07, 2020, 03:48:06 PM »
So Peak Snow is about 2035.
peak snowfall maybe at 2035.
But by then more rain. Rain on snow = less or no snow lying on the ground for less time in the year.
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ArcTickTock

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Re: The 2020 melting season
« Reply #5921 on: September 07, 2020, 03:48:56 PM »
2012 seems such a freak outlier in some sense.  In the absence of 2012, 2020 would be making headlines right now.

Paul

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Re: The 2020 melting season
« Reply #5922 on: September 07, 2020, 05:08:38 PM »
2012 seems such a freak outlier in some sense.  In the absence of 2012, 2020 would be making headlines right now.

It was a freek in the sence weather conditions perhaps did not favour such a low extent but a look at the ice condition during 2012 did suggest the ice was vulnable and the GAC really was the perfect storm.

This year had much less dispersion but rapid ice melt and compaction on the Siberian side of the basin coupled with alot of warmth in the air and ocean meant this year was always going to be low but I fear when JAXA returns with their data, it will show this year's extent line alot closer than I thought it would be.

Pagophilus

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Re: The 2020 melting season
« Reply #5923 on: September 07, 2020, 06:18:42 PM »
So Peak Snow is about 2035.
peak snowfall maybe at 2035.
But by then more rain. Rain on snow = less or no snow lying on the ground for less time in the year.
Great point.  To build on this a little, it is also worse for 'snow on the ground' when snow storms degenerate into rain storms, and the snow starts melting right away.  Or when the season of rainier storms arrives earlier and earlier in the year.  One would think that in a warming environment that would happen more and more often (or rather, is happening more often).  Positive feedback effect could be powerful.
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oren

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Re: The 2020 melting season
« Reply #5924 on: September 07, 2020, 06:23:09 PM »
Welcome back Pagophilus from your August getaway. Just in time for the minimum.

Pagophilus

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Re: The 2020 melting season
« Reply #5925 on: September 07, 2020, 06:32:35 PM »
A glimpse of the fragile state of the ice edge nearest to Severnaya Zemlya.  Contrast heightened on Photoshop to 'see' through fine, ribbony clouds.
« Last Edit: September 07, 2020, 06:55:04 PM by Pagophilus »
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Re: The 2020 melting season
« Reply #5926 on: September 07, 2020, 06:33:15 PM »
Welcome back Pagophilus from your August getaway. Just in time for the minimum.
Thanks, oren.  Good to be back!
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ArcticMelt2

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Re: The 2020 melting season
« Reply #5927 on: September 07, 2020, 07:03:15 PM »
Ice on the Pacific side is approaching 2019 and may fall even further.

https://twitter.com/AlaskaWx/status/1302648246204940289

Quote
The September 5th combined sea ice extent in the Chukchi & Beaufort Seas is 9th lowest since 1979 in @NSIDC passive microwave data. Effectively all of the #seaice is in the Beaufort Sea, as the Chukchi Sea basin is now 99.7% open water. #akwx #Arctic @Climatologist49 @ZLabe


ArcticMelt2

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Re: The 2020 melting season
« Reply #5928 on: September 07, 2020, 07:05:11 PM »
The minimum is not earlier than September 12-13th.

gandul

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Re: The 2020 melting season
« Reply #5929 on: September 07, 2020, 07:36:59 PM »
I bet there is a nice rebound of 4+years  MYI this year

Anybody knows where the NASA Lagrangian Particle ice simulation latest maps are located?
Nevermind
https://nsidc.org/data/nsidc-0749
« Last Edit: September 07, 2020, 08:25:26 PM by gandul »

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Re: The 2020 melting season
« Reply #5930 on: September 07, 2020, 07:45:17 PM »
In what region would you expect that rebound, gandul?

Freegrass

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Re: The 2020 melting season
« Reply #5931 on: September 07, 2020, 08:14:37 PM »
Latest Five Day Forecast
Wind @ Surface + Total Precipitable Water
Large GiF!

Not cooling down just yet...
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gandul

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Re: The 2020 melting season
« Reply #5932 on: September 07, 2020, 08:26:14 PM »
In what region would you expect that rebound, gandul?
Check it out yourself above

GoSouthYoungins

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Re: The 2020 melting season
« Reply #5933 on: September 07, 2020, 08:31:08 PM »
4-year-old ice can be half a meter thick.
big time oops

Thomas Barlow

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Re: The 2020 melting season
« Reply #5934 on: September 07, 2020, 09:38:32 PM »
How low will it go?
This shows the turning points for the last 10 years.

http://nsidc.org/arcticseaicenews/charctic-interactive-sea-ice-graph/

oren

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Re: The 2020 melting season
« Reply #5935 on: September 07, 2020, 09:40:35 PM »
I bet there is a nice rebound of 4+years  MYI this year
So it would appear according to the images. The older ice moved westward this melting season and was mostly saved from Fram and Nares export. In addition, there was nearly no export from the Beaufort to the Chukchi. I should note that in the winter there was a major export event from the region of the pole, I wonder if NSIDC have tracked it properly - this can be verified by viewing an animation of ice age distribution over the last year.
Some of the older ice appears to be stuck in the dwindling Beaufort arm though, so it may not survive or be a very thin shadow of its former glory. And another part of that ice has been exported down the CAA channels in the PGAS and was lost, again I wonder if the tracking algorithm can notice such small details.

A-Team

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Re: The 2020 melting season
« Reply #5936 on: September 07, 2020, 11:16:48 PM »
Actually the many Ascat animations posted earlier best capture the ice motion from Oct 15 to May 15, that's why we enhance them rather than use secondary low resolution products that don't allow ice feature tracking or delaunay shape change quantitation.

More recently, there's been some question of extraordinary melt atlantification of the Atlantic side (largely decoupled from shelf bathymetry) vs the wind simply blowing the ice pack north and west. The time series below suggests some of both but going by the arrows, feature conservation, lack of compactification and 5dp GPS of the newly moored Polarstern buoys, it was mainly just the wind.

Thus this is different from the massive opening north of Greenland which the Polarstern's captain correctly described as ice melt from the extraordinary heat wave (documented at Alert and Morris Jessup wx stations), rather than bulk pack advection towards the NSI creating open water gaps.

Regardless of how it got there, the largely unprecedented position of the ice pack today has many implications for the coming freeze season in terms of surface mixing of areas usually ice covered, possible lateral extension of long term atlantification, winter Fram export, and reduced Barents stratificational maintenance.

The Atlantic side has had a much more orderly progression than the Beaufort-Chukchi (which got just hammered in late July by an anti-cyclone). For clarity, the shrinkage is shown in a matched-pair palette created for this type of adjacency map at Colorbrewer2 (and used to good effect on NOAA-PSL maps). The AMSR2_UHH are set 4 days apart which surprisingly provides enough spacing. They are flipped horizontally so the two views face each other to bring matching areas visually closer.
« Last Edit: September 08, 2020, 12:57:19 AM by A-Team »

jdallen

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Re: The 2020 melting season
« Reply #5937 on: September 07, 2020, 11:48:53 PM »
In what region would you expect that rebound, gandul?
Check it out yourself above
Not his job to prove your point, please.

You made the assertion, your job to lay it out and describe your evidence for it.
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Re: The 2020 melting season
« Reply #5938 on: September 08, 2020, 12:09:57 AM »
The post was later edited to include some more graphics and information which makes it a little difficult to read things contemporaneously. Kinda makes my comment seem low effort rather than legitimately intuitive as it was at the time of posting. In the future it might be nice to include a trailhead such as “see the edit to my post above” or similar so other readers aren’t confused. Just a thought though, lmk if it’s too off topic Oren

cesium62

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Re: The 2020 melting season
« Reply #5939 on: September 08, 2020, 12:39:39 AM »
In what region would you expect that rebound, gandul?
Check it out yourself above
Not his job to prove your point, please.

You made the assertion, your job to lay it out and describe your evidence for it.
Concur.  The amount of yellow+red in 2020 visually looks roughly the same as in 2019.  More to the point, the yellow and red for 2020 is closer to the CAA.  So the compaction and current flows over the next year is really going to thin out that band and stretch it through the Beaufort and Chukchi, where it will melt next year.  2021 is looking kinda scary on that front...



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Re: The 2020 melting season
« Reply #5940 on: September 08, 2020, 01:08:52 AM »
It also appears that there is some serious bifurcation going on between the older (yellow/red) strata and the youngest ice, which may suggest that there is a set of older floes which continue to persist, but they are not surviving en masse every year to replenish a yearly “graduating class” of significant multi year ice. As cesium also mentioned, it may actually be a similar volume of ice that is just getting moved around and stretched thinner until it inevitably exports/garlic presses/melts in situ, leaving behind a gap which is not actively being filled by anything but younger and younger ice.

To take this further, I wonder if this sort of degradation is what is finally allowing the mega crack/weakness north of Greenland and the overall detaching and rotating of the pack as a whole to occur. With these old bastions being stressed to a breaking point, it may be the case that we are edging ever closer to successive “point of no return” dominoes falling one after another. With such a complex and chaotic system, I would not be surprised if we are watching this as we speak.

I have a hunch that over the next few years, multiple new large scale phenomena (such as the mega crack) that few to none of us would have seen coming may begin to arise, and as these developments manifest, once again the “Arctic as we know it” will be shaken up and redefined as the system approaches the first BOE, whenever that may be.

UCMiami

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Re: The 2020 melting season
« Reply #5941 on: September 08, 2020, 02:15:11 AM »
While I understand the classification of ice by age in a historic sense, I wonder how useful it is in the modern arctic. Current summer minimum is 25% of maximum and what ice remains has been seriously degraded. Most of it will likely have lost 50-75% of its thickness over a melt season like 2020 if it hasn't completely melted out. And in the last number of years larger portions of the oldest/thickest ice has been transported out of the CAB to its destruction.

I also understand that ice character does change over time as it loses brine and becomes more solid freshwater - I'm unsure how significant this change is but it seems to be secondary to the larger forces involved in melt/freeze seasons.

What I am suggesting is age maps to me really do not tell the story they used to when age was an indication of thickness. At this point I suspect there are some 4 year flows that are less than a meter thick, and some first year ice that somehow retained a meter of thickness.

(The distance the various ice buoys have traveled through winter and summer also makes me wonder how well these maps really are able to track ice age.)

bbr2315

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Re: The 2020 melting season
« Reply #5942 on: September 08, 2020, 02:54:04 AM »
It also appears that there is some serious bifurcation going on between the older (yellow/red) strata and the youngest ice, which may suggest that there is a set of older floes which continue to persist, but they are not surviving en masse every year to replenish a yearly “graduating class” of significant multi year ice. As cesium also mentioned, it may actually be a similar volume of ice that is just getting moved around and stretched thinner until it inevitably exports/garlic presses/melts in situ, leaving behind a gap which is not actively being filled by anything but younger and younger ice.

To take this further, I wonder if this sort of degradation is what is finally allowing the mega crack/weakness north of Greenland and the overall detaching and rotating of the pack as a whole to occur. With these old bastions being stressed to a breaking point, it may be the case that we are edging ever closer to successive “point of no return” dominoes falling one after another. With such a complex and chaotic system, I would not be surprised if we are watching this as we speak.

I have a hunch that over the next few years, multiple new large scale phenomena (such as the mega crack) that few to none of us would have seen coming may begin to arise, and as these developments manifest, once again the “Arctic as we know it” will be shaken up and redefined as the system approaches the first BOE, whenever that may be.

I strongly agree with this, and this also begs the possibility that we do NOT see a BoE, but a transition to a different state where there is a persistent 1-2M KM^2 of remnant area / extent in CAA, CAB, and Beaufort (?) and a "new" state.

If anything, 2020 confirms the Lincoln Sea will NOT be the last redoubt or anything near it for MYI.

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Re: The 2020 melting season
« Reply #5943 on: September 08, 2020, 03:15:14 AM »
Latest Five Day Forecast
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oren

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Re: The 2020 melting season
« Reply #5944 on: September 08, 2020, 04:29:23 AM »
The Lincoln Sea covered with snow. Getting its albedo back just when it doesn't matter anymore, and having a nice insulating blanket just when it's better not to.

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Re: The 2020 melting season
« Reply #5945 on: September 08, 2020, 05:22:15 AM »
Is there a particular reason why the 2020 data from the Bremen AMSR2 extent graph is so much closer (or maybe even on top of at this point) the 2012 data while NSIDC still shows 400k+ km^2 of separation still? Is it solely due to resolution or is there something deeper causing the two to differ so much?

Frivolousz21

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Re: The 2020 melting season
« Reply #5946 on: September 08, 2020, 05:28:47 AM »
DMI 80N now dropping like a rock. But look how long the melting season lasted... A new normal?

Most definitely not a new normal
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peterlvmeng

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Re: The 2020 melting season
« Reply #5947 on: September 08, 2020, 06:30:40 AM »
Shall we start the freezing season thread?

Pavel

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Re: The 2020 melting season
« Reply #5948 on: September 08, 2020, 06:47:54 AM »
Shall we start the freezing season thread?
Even if the ice surface is frozen the ocean heat flux continues to melt the ice from the bottom side. In the Beaufort sea it will last well into October. This year I think more energy stored in the Ocean due to the GAAC in July

Frivolousz21

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Re: The 2020 melting season
« Reply #5949 on: September 08, 2020, 07:04:48 AM »
Is there a particular reason why the 2020 data from the Bremen AMSR2 extent graph is so much closer (or maybe even on top of at this point) the 2012 data while NSIDC still shows 400k+ km^2 of separation still? Is it solely due to resolution or is there something deeper causing the two to differ so much?


Mostly resolution.  The nsidc 25km isn't picking up the open water as well in the CAB, greenland sea, lincoln sea, beaufort, and CAA.

Also data smoothing.  I don't know how nsidc does it.

But bremen IIRC has a 5 day mean heavily weighted to the most recent 2 days.

The most recent bremen graphic has them in a virtual tie.

But 2012 dips even lower next week.

I doubt 2020 matches that
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