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Phoenix

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Re: The 2020 melting season
« Reply #500 on: April 28, 2020, 03:55:08 AM »

Only outdone by your response.

My post is an investment in the discussion about the desired scope of the thread. As a lurker, my experience has been that people like to tell themselves that this is a "science' thread. 

Guessing the future weather events of the 2020 melt season w/o any scientific rationale doesn't seem to fit the scope of a science thread. Yet there will be hundreds of comments cluttering up the thread to that effect.

For those of us who would easily make an even money bet that 2020 will not retain #1 position for the duration of the season, we can make an equally unscientific response projecting the opposite and then we can have an unscientific pissing contest about who is the better guesser.

I'll stick with 2012 as the likely record holder in volume and extent come September. Does that add anything of value to the readers? No. If I explain why I think that, that seems appropriate.

We have new moderators who have the opportunity to look at this with a fresh perspective and provide guidance.

oren

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Re: The 2020 melting season
« Reply #501 on: April 28, 2020, 04:50:24 AM »
The new moderator's long-winded stream-of-consciousness position about this thread is:
* Off-Topic comments, jokes and other "nonsense" are always welcome on the forum in appropriate threads, but not on the melting season thread, one of the highest-rating threads that is home to many lurker readers.
* Personally-charged comments and slights of honor should be avoided (even when justified...), as they necessarily create back and forth posts and increase clutter. And are of course impolite.
* Comments about comments, i.e. meta-discussion, should be minimized. Not necessarily avoided, but reduced and used with care. Use "report to moderator" or PM me about posts that you believe should be dealt with, but be aware that I am monitoring this thread continuously.
* General long term predictions about the season ("I think a BOE is impossible this year") are better off in a separate thread, and I am happy that such a one was recently opened. The exception is extrapolations of current data and situations ("I think the high CAB thickness precludes a meltout, based on average melting patterns").
* Deep discussions about scientific issues, which certainly could impact the melting season, should be held in separate threads. For example, contrails and their effects on sea ice, aerosols or lack thereof, La Nina, the Blob, soot from China or the fires soon to be in Siberia, etc., while a few comments on each such issue are welcome on this thread. Once it becomes heavy and arguments are flying around, or various papers posted, move it elsewhere. Here it will be lost and will disrupt the news flow.
* This thread is mainly about actual developments happening during the melting season, and comparisons with previous melting seasons.
* Comments about the data posted by JCG and Gero in the data thread should be posted in this thread, rather than in the data thread itself.
* Posters wishing to thank others for exceptional contributions (of which we happily have many) should consider using the Like button for most occasions.
* The moderator will use moderation in moderating, so as to avoid creating dissent and hurt feelings, and in consideration of his inexperience in such matters, but will act as necessary to ensure smooth and fruitful discussion.
* Often sporadic or borderline comments will not be dealt with to avoid disruption by the moderator, but similar comments might get the edit later when something becomes a repeated phenomenon.
* Should you undergo a moderation edit, please don't take this as a personal attack or as a hint that your contributions are unwelcome (unless specifically stated.....)
* If you are a lurker and are afraid or hesitant to post because of all these rules, be aware that new posters are treated more gently and are very welcome in their initial posting efforts. Bear in mind there is a "stupid" questions thread where you can ask most anything.

F.Tnioli

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Re: The 2020 melting season
« Reply #502 on: April 28, 2020, 10:25:46 AM »
We have seen a massive drop in aerosols and the conversation preceded this post further discussing the impact of contrails.

I think Freegrass is correct. The aerosol problem this year is unprecedented. A page or two back, or it may have been another thread, someone posted that we contribute roughly 8 Pinatubos of SO2 a year to the atmosphere. What will the impact be of one less Pinatubo a year? Or two? Or three? Or even four? The best case is we have two "reverse Pinatubos" the worst, is probably three or four. That is a recipe for absolute catastrophe in the Arctic, especially when you compound it with the impact of contrails / etc.
You probably refer to this post: https://forum.arctic-sea-ice.net/index.php/topic,3017.msg261429.html#msg261429 , in particular its paragraph following "3." one. And while "absolute catastrophe" is not likely to happen - i deem "absolute catastrophe" being the state when Arctic ocean top layers stay much above freezing point 24/365, like it was in the past when crocodiles lived there, - i concur that this melt season is likely to mark the beginning of the shift which will eventually lead to such a state. Huge thermal capacity, you know. Will take more than one or two summers to get there.

Obviously, melt ponding will be our early indicator of how dire a situation this melt season is likely to end up being. Extra attention to melt ponds, with perhaps finding new methods to quantify melt ponding better than we were able before, would very much help.
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!

F.Tnioli

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Re: The 2020 melting season
« Reply #503 on: April 28, 2020, 10:31:38 AM »
...
* Personally-charged comments and slights of honor should be avoided (even when justified...), ...
Gentlemen - everyone! I ask us all to note the above bold / large (my enhancement) words and always remember them. At _all_ times.

I thank you, Oren, for putting it this way. This will allow us all to remain professional, here. Please strike down anyone violating this particular part - "even when _justified_" - without mercy. I think this is the greatest part you just did, for this topic!
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blumenkraft

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Re: The 2020 melting season
« Reply #504 on: April 28, 2020, 10:48:39 AM »
I thank you, Oren

+1

Those are well thought out and reasonable boundaries.

Personally, i want to put emphasis on the

Quote
* Comments about the data posted by JCG and Gero in the data thread should be posted in this thread, rather than in the data thread itself.

point. For the love of God, please let the boys do their thing over there and don't clutter/distract!
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Freegrass

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Re: The 2020 melting season
« Reply #505 on: April 28, 2020, 12:33:56 PM »
According to Nico Sun's area calculations, we are back in spot #1 today.
And I think that's where we'll stay all season...
Six off topic messages because of this one little sentence I wrote... That's insane! (seven now)
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SimonF92

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Re: The 2020 melting season
« Reply #506 on: April 28, 2020, 12:36:52 PM »
According to my mining script regional conditions are poor compared to the last decade.

Would it be more informative if I changed how many years the current year is compared to. Maybe post-2012 instead?

I suggest an automatic ban from this thread after 3-strikes, because its the same every year in the melting/freezing threads. Not going to answer anything re this post that isnt related to the ice.
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F.Tnioli

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Re: The 2020 melting season
« Reply #507 on: April 28, 2020, 01:33:01 PM »
...
Would it be more informative if I changed how many years the current year is compared to. Maybe post-2012 instead?
...
Yes, it would be. 2013 and onwards is a whole new league of its own.
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nanning

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Re: The 2020 melting season
« Reply #508 on: April 28, 2020, 02:49:52 PM »
^^
In an acceleratingly changing system, longer term averages may no longer be of significance.
Where to calibrate?
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Freegrass

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Re: The 2020 melting season
« Reply #509 on: April 28, 2020, 02:54:22 PM »
The five day forecast looks boring. But maybe boring is good for a change?
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Aluminium

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Re: The 2020 melting season
« Reply #510 on: April 28, 2020, 03:05:04 PM »
2020 tries to self-isolate.

Stephan

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Re: The 2020 melting season
« Reply #511 on: April 28, 2020, 07:24:31 PM »
According to my mining script regional conditions are poor compared to the last decade.

Which sea is represented by "dd", the first entry of your chart?
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Pavel

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Re: The 2020 melting season
« Reply #512 on: April 28, 2020, 08:35:12 PM »
2020 tries to self-isolate.
I expect this year will be worse than 2019 especially if the Siberian side will melt out early, what is very likely. The Beaufort sea and CAA look more safely but everything can happen

SimonF92

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Re: The 2020 melting season
« Reply #513 on: April 28, 2020, 10:07:38 PM »
Thanks for the input everyone, I will think about it. Its possible to make a facet-grid of several different baselines (2010+, 2013+ etc).

Stephan, i noticed that after I posted, its a mathematical-working column i forgot to trim that stands for 'delta-delta', shorthand for differences of differences. Ill fix the code as it shouldnt be there.
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Freegrass

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Re: The 2020 melting season
« Reply #514 on: April 28, 2020, 10:19:39 PM »
Fast ice breaking off north of Greenland, close to Nares Fram Strait.
« Last Edit: April 28, 2020, 10:31:47 PM by Freegrass »
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Niall Dollard

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Re: The 2020 melting season
« Reply #515 on: April 28, 2020, 10:27:12 PM »
Fast ice breaking off north of Greenland, close to Nares Strait.

Fram Strait

Freegrass

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Re: The 2020 melting season
« Reply #516 on: April 28, 2020, 10:33:54 PM »
Fast ice breaking off north of Greenland, close to Nares Strait.

Fram Strait
Thanks for the correction Niall! I always mix those two up...

That's early for fast ice break-off, isn't it?
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jdallen

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Re: The 2020 melting season
« Reply #517 on: April 28, 2020, 11:06:19 PM »
NSIDC Total Area as at 27-Apr-2020 (5 day trailing average) 11,545,487 KM2         
         
Total Area         
 11,545,487    km2      
-490,913    km2   <   2010's average.
-69,638    km2   <   2019
-774,162    km2   <   2000's average.
         
 Total Change    -98    k   loss
Peripheral Seas   -67    k   loss
Central Seas___   -31    k   loss
<snippage>
- 2020 Area is -70 k less than 2019       

- An impressive loss,
<more snippage>
see https://cryospherecomputing.tk/

Area is tracking 2016 pretty closely.  It was saved from beating 2012 only by shifts in the weather in July as I recall.  As it was, ice quality and volume were still butchered.

It will be interesting to see if area drops below 2016 over the next few days, which considering how much vulnerable ice there is in peripheral seas, shouldn't be hard.
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Aluminium

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Re: The 2020 melting season
« Reply #518 on: April 29, 2020, 08:03:43 AM »
April 23-28.

2019.

Niall Dollard

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Re: The 2020 melting season
« Reply #519 on: April 29, 2020, 01:10:23 PM »
That's early for fast ice break-off, isn't it?

I don't know FG.

Hard to know what is normal or typical anymore !

Early May last year was different because we had an open Nares Strait. Floes were continuously breaking off in the Lincoln Sea.

Then on May 10th, a crack rapidly spread eastwards from there, right along to Cape Morris Jesup . Next day crack rounded the top continued southeast down along north east coast of Greenland and then we had a huge separation all the way from NE Greenland coast all the way to the Nares Strait.
 

F.Tnioli

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Re: The 2020 melting season
« Reply #520 on: April 29, 2020, 02:33:37 PM »
...
It will be interesting to see if area drops below 2016 over the next few days, which considering how much vulnerable ice there is in peripheral seas, shouldn't be hard.
Interesting indeed, but needs to be observed in conjunction with data about ongoing cloud cover (or lack of) over said peripheral seas. There are two factors we expect to play a big role in the process - vulnerable state of ice and clean air, and yet they both are minimized when/where there is no sunlight present over any given peripheral sea, roughly speaking. Thus i'd say it's not just "if" area drops or not, - it's "if" area drops in those seas which are any well soaked in direct sunlight.

And to me it's also very interesting to see if we'll have more such areas than usual. Current weather / vortex effects of course overrides, but there is now that general effect of way less nuclei in clouds - so bigger water droplets / snowflakes, means precipitation should deplete clouds faster.
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Phoenix

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Re: The 2020 melting season
« Reply #521 on: April 29, 2020, 09:53:08 PM »
April 23-28.

These gif's are an awesome contribution to the site and even better now that we can compare to last year. Pacific side was much more advanced in terms of 2D ice loss last year at this point. Atlantic side is further along this year where we see some open water N of 80N. The cliff at 82N which separates the Nansen Basin from the shallow Atlantic will get a good test this season.

Milwen

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Re: The 2020 melting season
« Reply #522 on: April 29, 2020, 11:12:28 PM »
We have liftoff north of Greenland, to the left of Nares


gerontocrat

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Re: The 2020 melting season
« Reply #523 on: April 29, 2020, 11:36:27 PM »
Russia tells us to expect a warm Siberian late spring & early summer.
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Re: The 2020 melting season
« Reply #524 on: April 30, 2020, 09:39:28 PM »
Hmmm... 🤔


blumenkraft

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Re: The 2020 melting season
« Reply #525 on: April 30, 2020, 10:04:50 PM »
We have liftoff north of Greenland, to the left of Nares

Sorry to nitpick, but north of Greenland is on the right of Nares (in the east). The picture is on the left of the Nares (to the west) and it's the CAA (Canadian Arctic Archipelago).
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F.Tnioli

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Re: The 2020 melting season
« Reply #526 on: April 30, 2020, 10:41:41 PM »
Hmmm... 🤔
500 km3 of ice gone in last 10 days of April, eh. If this what's going on, then things melt as if it was last 10 days of May, not April. Like lengthening melt season by 1 month, sort of. For BoE, "extra 3 weeks" should suffice if one would do some silly numbers on a napkin based on what we saw in 2019. Could be we're starting to see even more melt power than anticipated per some above concerns, Pinatubo and all. Please keep 'em volume graphics coming if possible once a week. Few more weeks should tell us helluva lot of story already if this pace would continue.
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Phoenix

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Re: The 2020 melting season
« Reply #527 on: May 01, 2020, 01:03:33 AM »
what's the difference between PIOMAS volume and DMI volume?

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Re: The 2020 melting season
« Reply #528 on: May 01, 2020, 01:28:51 AM »
what's the difference between PIOMAS volume and DMI volume?

Different models

PIOMAS http://psc.apl.uw.edu/research/projects/arctic-sea-ice-volume-anomaly/

DMI: http://ocean.dmi.dk/arctic/icethickness/icetext.uk.php



That's a big one slowly making its way down the Fram (~110 km wide)

Freegrass

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Re: The 2020 melting season
« Reply #529 on: May 01, 2020, 01:51:58 AM »
That's a big one slowly making its way down the Fram (~110 km wide)
That's been sitting there for almost 2 weeks now.
Translation: Fram export has been very slow lately.
« Last Edit: May 01, 2020, 09:36:16 AM by Freegrass »
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PragmaticAntithesis

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Re: The 2020 melting season
« Reply #530 on: May 01, 2020, 02:01:12 AM »
<snip>
Fram export has been very slow.

Just about the first time we've heard that all year!
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Re: The 2020 melting season
« Reply #531 on: May 01, 2020, 02:39:21 AM »
what's the difference between PIOMAS volume and DMI volume?

No idea on that one but the theory between the differences between crysosat and PIOMAS is snowcover on the pack. Maybe the DMI model is similar although whenever I look at the DMI thicknesses graph, it does seem to look suspicious to me and other people.

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Re: The 2020 melting season
« Reply #532 on: May 01, 2020, 05:39:53 AM »
If you look at the DMI and PIOMAS graphs for volume side by side, you'll notice that the PIOMAS graph shows volume dipping lower than DMI. I to am wondering why this is
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oren

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Re: The 2020 melting season
« Reply #533 on: May 01, 2020, 05:51:42 AM »
I would ask that discussion of the DMI volume (based on Hycom-CICE model) and its comparison with PIOMAS and with actual measurement (Cryosat, SMOS) take place in a separate new thread - and not the existing one that compares PIOMAS vs. Cryosat.
The reason for that is I believe the DMI model is of less value than the other volume measures, and I don't want it to bog down this thread. Every year the same issues arise, and it would be good to have a separate thread discussing it. And who knows, we might suddenly discover that the DMI volume is of high value.
Until such comparison take place and some proof of value is found (or maybe there is an existing thread proving it? I can't recall), I ask that people don't make too many posts in this thread based on the DMI volume. It is okay to mention it and post charts from time to time but don't let it become the focus or cause too much clutter.

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Re: The 2020 melting season
« Reply #534 on: May 01, 2020, 09:25:30 AM »
The 00z EURO would be catastrophic re: melt ponding.

This is the D5-10 anomaly average, but by D10 -- far out, I know -- the HP is pushing 1060MB. The 500MB blocking is insane.
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« Last Edit: May 01, 2020, 11:39:24 AM by oren »

Stephan

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Re: The 2020 melting season
« Reply #535 on: May 01, 2020, 10:26:13 AM »
That's a big one slowly making its way down the Fram (~110 km wide)
This big floe consists of probably two-year or even multi-year sea ice?
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Re: The 2020 melting season
« Reply #536 on: May 01, 2020, 12:18:09 PM »
This is the D5-10 anomaly average, but by D10 -- far out, I know
<Please avoid posting forecasts more than 5 days out. O>
I'd be interested to see your longer term forecasts on Atmospheric connections, structure, and long range weather forecasting

Freegrass

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Re: The 2020 melting season
« Reply #537 on: May 01, 2020, 02:03:18 PM »
I can't remember seeing ice temperature being posted here before. It's amazing how much the ice has warmed up in the last month.


Click on the animation button below the image.
http://polarportal.dk/en/sea-ice-and-icebergs/sea-ice-temperature/
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Re: The 2020 melting season
« Reply #538 on: May 01, 2020, 02:10:14 PM »
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Stephan

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Re: The 2020 melting season
« Reply #539 on: May 01, 2020, 02:12:36 PM »
The ice temperatures in 2020 do not differ fundamentally from what has been observed the last years. I had a look athe DMI website (thank you for the link) and found that on May 1, 2019 the temperatures were even higher than this year. 2018 (and also 2014) was cooler, and for 2017 to 2015 I do not see a significant change from today's values. But this comparison is made by eye-balling. There are of course quantitative evaluations available.
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Re: The 2020 melting season
« Reply #540 on: May 01, 2020, 03:03:49 PM »
I don't think there's much to learn from ice temperatures, right? I was just amazed to see how much the temperature had changed during this last month. I don't think it'll matter much for the rest of the season.
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Richard Rathbone

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Re: The 2020 melting season
« Reply #541 on: May 01, 2020, 03:16:13 PM »
what's the difference between PIOMAS volume and DMI volume?

DMI is an operational forecast model.
PIOMAS is a total volume measurement model.

They both model the same physics in much the same way, but they make different compromises because they are built to answer different questions.

Because the physics is the same they are each capable of doing the job the other one does, but they are likely to be worse at it.

If you want an operational forecast (what will the ice conditions be where I want to travel in the next couple of days) use DMI. If you want to know what the volume was in the past, use PIOMAS.

Some features of the physics (in particular the way the melting point changes with salinity) make the equations tricky to solve without numerical instabilities, and this particularly plagues the operational forecast models. Consequently they make rather more severe compromises with the physics than PIOMAS does and are fairly hopeless compared to PIOMAS when they step outside the narrow range of questions they are built to answer. PIOMAS crushes them in seasonal forecasting even though they are forecast models and PIOMAS is a measurement model.


oren

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Re: The 2020 melting season
« Reply #542 on: May 01, 2020, 03:24:50 PM »
RR, from now on please discuss DMI volume at the new thread linked by JH above, to which I copied your post.

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Re: The 2020 melting season
« Reply #543 on: May 01, 2020, 07:04:35 PM »
Look at all that blue at the Atlantic side, right up to the north pole.

Could indicate wet snow/ice for how i understand it.
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blumenkraft

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Re: The 2020 melting season
« Reply #544 on: May 01, 2020, 07:15:38 PM »
Also rather dark in M10 band, indicating wetness.
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Niall Dollard

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Re: The 2020 melting season
« Reply #545 on: May 01, 2020, 07:43:43 PM »
We do have a research vessel located in that supposed "melt" area (The Polarstern).

Here is another image view from Univ Bremen and where Polarstern is currently located. Acoording to that Polarstern is in the yellow/green area which is much reduced concentration.

But unless we hear reports soon from Polarstern that they are sloshing about in melt ponds, I very much doubt that Bremen colorations are accurate.

As I type current temperature at Polarstern is -13 C. So I doubt there is much melting there yet. 

blumenkraft

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Re: The 2020 melting season
« Reply #546 on: May 01, 2020, 08:00:01 PM »
sloshing about in melt ponds.

I think (i hope) it's not that bad.

This 'wetness' could also mean that it's just very humid there at the ice surface. There are a lot of cracks, releasing heat from the seawater into the (still) cold air.
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Niall Dollard

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Re: The 2020 melting season
« Reply #547 on: May 01, 2020, 08:07:39 PM »
There have been cracks in the area. But I cant see them releasing that much heat to affect the Bremen chart so much. Besides much of the leads will freeze over quite quickly.

The legend for the Bremen chart refers to ice concentration and yellow/green descends to 50% concentration.

This is clearly not true.

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Re: The 2020 melting season
« Reply #548 on: May 01, 2020, 08:10:08 PM »
Niall, of course, it's not true.

But the sensors see something there. What is it in your opinion?
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bluice

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Re: The 2020 melting season
« Reply #549 on: May 01, 2020, 08:16:00 PM »
Slater is predicting the ESS to melt out before the Laptev it seems. That would be interesting...

This is from Slater thread. Pls take a look at the picture.  Something odd seems to be going on there. The North Hole or just a sensor artifact?

Edit: couldn’t post the picture with phone. The pic on Freegrass’s post shows the ”Hole” between Svalbard and the Pole