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meddoc

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Re: The 2017 melting season
« Reply #2800 on: July 13, 2017, 10:54:52 AM »

Because NSIDC compactness has had a huge rebound and this model is all based on concentration.
Indeed this really smells like a rebound year itself, and with that cyclonic circulation around Greenland.
We'll see, all peripheral seas are for sure compromised, but I suspect the progress will slow down when reaching the CAB. Area got a bit of a mini-cliff before, but now in terms of anomaly it recovered to just over -1 million, see last Wipneus entry on NSIDC data

It really amazes me, that even some Veterans have Hopium for a Rebound Year.
Maybe it will be in Terms of dispersed fragmented slush being dissipatd throughout the Arctic Ocean. But that, then will be prone for a Sweepout by late Cyclone(s).

romett1

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Re: The 2017 melting season
« Reply #2801 on: July 13, 2017, 11:54:33 AM »
And one more:  broader view of the western Beaufort to the eastern ESS.
The Beaufort seems very ready to drop a chunk of extent.

Here is the latest situation, I tried to point out problem spots. Image: ftp://ftp-projects.cen.uni-hamburg.de/seaice/AMSR2/

Adam Ash

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Re: The 2017 melting season
« Reply #2802 on: July 13, 2017, 12:19:01 PM »
No sign of the Wrangle Arm this season.  Will that allow the gyre to shove more multi year ice across from Alaska to the death zones against Russia?

(Noting, in the interim, that right now the surface winds seem to be trying to shove the entire contents of the Beaufort and ESS into the CAA Garlic Press!)
« Last Edit: July 13, 2017, 02:47:15 PM by Adam Ash »

Tigertown

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Re: The 2017 melting season
« Reply #2803 on: July 13, 2017, 01:42:13 PM »

NSIDC SIE
X 106 km2

2017,    07,  09,      8.657
2017,    07,  10,      8.591
2017,    07,  11,      8.434
2017,    07,  12,      8.274

That's a 157k drop on the 11th and 160k drop on the 12th.

F.Tnioli

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Re: The 2017 melting season
« Reply #2804 on: July 13, 2017, 01:57:21 PM »
Let's keep it on-topic as possible, and as short as possible. And let's try to add images.

People come here for quick info on how the melting season is progressing as we speak. Not to read a book.

It was very on-topic, being logical continuation and explanation of my position about _possibilities_ for this melt season's minimum. I didn't start the talk. I merely joined the conversation. It was as short as possible for the goals i had with the message, too. One can't expect every matter being perfectly explainable in just dozen words, - some matters require somewhat bigger amount of words to be _properly_ described. I also added a video into my previous post, via link, - i dare think it's even better than a picture or two.

People who want to see pictures which show progress of this melting season will only need a single roll of a mouse wheel to skip my whole previous post, and it was my specific intention to help them do so when i shaped that video i posted exactly as a text link and not as an embedded video, which i hope demonstrates that i care as much as i can for all kinds of readers, - not only ones i was having a conversation with. Nobody forces any (other) visitors to read my previous post, too - you say it as if i am holding every visitor at a gun point making sure they are going to read that "book", if to use your term. Not the case.

Ok. Here for the people:



I'd comment it, but you said "no books". Oh well, at least i'd save time then, because if you forgot, - it takes many times more time to _type_ a book than to read it. Your appreciation of my previous effort is so motivating, you know? ;)

P.S. Most modern forums allow to use "spoiler" tag, which exists specifically for putting longer texts under it. Such texts are then not shown on the page unless the "spoiler" button is clicked by the reader to read the contents of such a spoiler. This allows detailed and long descriptions to co-exist completely peacefully with administrators' desire to see topics "tidy" and "short". Can we hope to see this functionality here, i wonder.

Tigertown

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Re: The 2017 melting season
« Reply #2805 on: July 13, 2017, 02:20:17 PM »
P.S. Most modern forums allow to use "spoiler" tag, which exists specifically for putting longer texts under it. Such texts are then not shown on the page unless the "spoiler" button is clicked by the reader to read the contents of such a spoiler. This allows detailed and long descriptions to co-exist completely peacefully with administrators' desire to see topics "tidy" and "short". Can we hope to see this functionality here, i wonder.

Thank you for running the forum Neven. As a volunteer, it is your right to keep this forum as simple as you can. Ideas like this require someone to read through comments, one by one, and decide what's what. More work for someone. I think that we should all appreciate what you do already, instead of asking you to do more. I always enjoy  F.Tnioli's comments, but I beg to differ on this one, unless you see fit to do it without it being a burden to you personally.

pauldry600

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Re: The 2017 melting season
« Reply #2806 on: July 13, 2017, 02:21:03 PM »
What Tigertown posted is what I come on this forum to see

While your post is interesting my reading is poor so I just pan down. Sorry

Jim Pettit

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Re: The 2017 melting season
« Reply #2807 on: July 13, 2017, 02:29:07 PM »
Per Neven's rules:

"Every comment in the melting/freezing season threads should pertain to that subject. These are the most popular threads for readers who don't comment, so don't bother them with off-topic stuff. Don't start [or engage in] discussions about [forum] rules in the [melting/freezing season] threads. PM Neven, or go to the Forum category".

So, please--and again--stay on topic here. Thanks.

iceman

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Re: The 2017 melting season
« Reply #2808 on: July 13, 2017, 02:41:51 PM »
   ....
My pixel-count-volume-loss-estimate from the 13th to the 21st: ~1.150km³, that is about 140km³ a day, pretty much the same loss-rate as between 1st and 12th. Forecast for the 15th has remained stable at around 7.350-7.400 km³ (all the big ifs still apply).
Interesting to see the projection of sustained volume melt, in view of Jim Pettit's interannual comparisons on ASIB and elsewhere.  If corroborated by PIOMAS, this would mean a volume anomaly at or near record lows into late July.

   ....
We'll see, all peripheral seas are for sure compromised, but I suspect the progress will slow down when reaching the CAB. ...
Sounds plausible, and underscores the ongoing tension between volume and area/extent measures this season.  Absent some GAC event, bottom melt during August and September will likely tilt the outcome one way or the other.

Tigertown

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Re: The 2017 melting season
« Reply #2809 on: July 13, 2017, 03:19:03 PM »
       It seems to me that at some point in past melt seasons, Greenland and the CAA served as a sort of backstop for compaction. This area usually stayed protected from SST's longer, too. With Nares open and likely the CAA itself soon to be, not only will the "Garlic Press" be open, allowing for loss of ice from the CAB, but there is also bound to be less compaction. This will make a huge difference in the vulnerability of the ice late in the season.
        An army that is loosing a battle falls back and regroups in order to make best use of it's strength. The ice, though very much unwittingly, has done just the same in past seasons, allowing it to hold out longer. How will the late season be affected if the ice can't compact as well, perhaps even dispersing more? If the winds and currents try to compact it elsewhere, SST's might be a problem, at least for a moment.

F.Tnioli

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Re: The 2017 melting season
« Reply #2810 on: July 13, 2017, 04:06:17 PM »
...

   ....
We'll see, all peripheral seas are for sure compromised, but I suspect the progress will slow down when reaching the CAB. ...
Sounds plausible, and underscores the ongoing tension between volume and area/extent measures this season.  Absent some GAC event, bottom melt during August and September will likely tilt the outcome one way or the other.
Sounds disputable. I see lots of blue in the picture i posted few messages above above 80° North on Atlantic side. Those are significant open water bits already, you know. Throw in a single even moderately strong Atlantic cyclone through those parts few weeks later, and we'd see big part of the CAB getting ice-free. Obviously, that's only a possibility, - one of many. But other years, no such possibility existed. Now it does.

Greenbelt

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Re: The 2017 melting season
« Reply #2811 on: July 13, 2017, 04:32:04 PM »
Short-term forecast looks to me like quite windy conditions (narrow pressure isobars) especially on the Russian/Atlantic side developing over the next day or two. GFS and ECMWF operational runs seem to agree on this.


oren

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Re: The 2017 melting season
« Reply #2812 on: July 13, 2017, 04:32:28 PM »
The big thing about the CAB is PIOMAS. If it's right, and the CAB is indeed thinner than usual, then there is no reason to assume a slowdown when we get to the CAB.

Shared Humanity

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Re: The 2017 melting season
« Reply #2813 on: July 13, 2017, 04:54:58 PM »
Let's keep it on-topic as possible, and as short as possible. And let's try to add images.

People come here for quick info on how the melting season is progressing as we speak. Not to read a book.
It was very on-topic, being logical continuation and explanation of my position about _possibilities_ for this melt season's minimum. I didn't start the talk. I merely joined the conversation....... blah, blah, blah, blah.....

Did you have to write a novel to defend your comment?  :o

F.Tnioli

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Re: The 2017 melting season
« Reply #2814 on: July 13, 2017, 05:11:39 PM »
The big thing about the CAB is PIOMAS. If it's right, and the CAB is indeed thinner than usual, then there is no reason to assume a slowdown when we get to the CAB.
Why, there is a simple way to see if PIOMAS's right - for a significant part of the CAB at very least. Namely, that way is to literally _see_ if it's thinner than usual. Eyeballing at its best! :D

Because yesterday was quite telling - lots of CAB was pretty visible. Here's part of it between 83 and 85 degrees North (roughly), exact coordinates of the cross in the middle of the picture are given, and the upper edge is 85 degrees North:



To me, this seems quite very much thinner than "usual". You?

edit: click the picture for full resolution
« Last Edit: July 13, 2017, 07:38:43 PM by F.Tnioli »

CalamityCountdown

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Re: The 2017 melting season
« Reply #2815 on: July 13, 2017, 05:16:55 PM »

NSIDC SIE
X 106 km2

2017,    07,  09,      8.657
2017,    07,  10,      8.591
2017,    07,  11,      8.434
2017,    07,  12,      8.274

That's a 157k drop on the 11th and 160k drop on the 12th.

Viewing NSIDC daily numbers versus the 5 day averages could lead the casual viewer to come to contradictory conclusions. The 2017 5 day average for today (as shown in the charts on the NSIDC website) only shows a drop a 89,000 square km2. Thus, the chart below appears to show SIE extent in 2017 is falling off the pace set in 2012. However, if only viewing the daily numbers, one could conclude based on the last two days that melting momentum is building in 2017 and was falling in 2012.

2017,    07,  08,      8.681,   -41       2012,    07,  08,      8.398,   -123
2017,    07,  09,      8.657,   -24       2012,    07,  09,      8.174,   -224 
2017,    07,  10,      8.591,   -66       2012,    07,  10,      8.13,     -44
2017,    07,  11,      8.434,   -157     2012,    07,  11,      8.032,   -98
2017,    07,  12,      8.274,   -160     2012,    07,  11,      7.946,   -86

The trend lines from 2012 and 2017 are likely to converge during the next two days as the 2012 drops of -123 and -224 will be replaced by drops of -29 and -49 in the average, particularly if the declines posted over the next two days are greater than -41 and -24 from 7/8 and 7/9.   


Shared Humanity

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Re: The 2017 melting season
« Reply #2816 on: July 13, 2017, 05:23:19 PM »

To me, this seems quite very much thinner than "usual". You?

Certainly very fragmented but how do you gauge thickness from such an image? We have a mobile, fragmented ice pack which I believe is the new and irreversible state of the Arctic. There was a report from a research vessel a couple of years ago that documented how a huge swath of thick MYI broke up into small floes when subjected to rough seas. Many of the small floes in this image could be rather thick MYI.

Shared Humanity

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Re: The 2017 melting season
« Reply #2817 on: July 13, 2017, 05:47:55 PM »
Off topic but permissible?
Mission Impossible?

"Please, can we drop the endless repetition of this (unusually high snowfall on the Arctic Ocean) until someone can cite physical basin-wide observational data that supports it and provide monthly maps of snow depth and snow condition that are something beyond an unvalidated algorithm?"

This quote from a very recent thread seems to me to ask for that for now and for an indefinite future is impossible. The resources available for for such a huge project are not there and I doubt will ever be. USAF polar satellite number #20 (cost USD 500 million?) has been sent to the junkyard. NSIDC's data record will stop if / when #18 finally gives up. (Already operating beyond its design life with no replacement in site. The US defence department is looking to
private and foreign government satellites for its future needs.)

ps: A clue regarding Arctic Ocean snowfall last winter to spring is Greenland, which accumulated snowfall about 100 gigatonne more than average and just about the maximum in DMI's 30 year record.


What we do know about global warming is there is more water in the atmosphere and more precipitation generally. In fact global warming will result in larger increases of precipitation in the Arctic than in the mid latitudes.

http://jasonbox.net/low-surface-ice-loss-greenland-year-due-heavy-snowfall-consistent-climate-warming/

While this does not prove that more snow fell in the Arctic this past winter, given the cyclone cannon that operated through much of the past winter, it is not outrageous to speculate that more snow than usual fell on the CAB. If not true in this most recent freeze season, it will be true, generally, going forward.

This is the new Arctic. The two most notable changes that we need to understand are increased fragmentation and mobility and increased humidity, storms and precipitation.
« Last Edit: July 13, 2017, 06:10:04 PM by Shared Humanity »

F.Tnioli

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Re: The 2017 melting season
« Reply #2818 on: July 13, 2017, 06:33:08 PM »
...
Did you have to write a novel to defend your comment?  :o

Can't answer this (in fact non-rhetorical) question here. We are to stay on topic. I'll send you a PM.


To me, this seems quite very much thinner than "usual". You?


Certainly very fragmented but how do you gauge thickness from such an image? We have a mobile, fragmented ice pack which I believe is the new and irreversible state of the Arctic. There was a report from a research vessel a couple of years ago that documented how a huge swath of thick MYI broke up into small floes when subjected to rough seas. Many of the small floes in this image could be rather thick MYI.

Already said "how": eye-balling plus coordinates given.

May be my eye-balling works not exactly the way your does, though? My eye-balling part includes noticing numerous miles-long open water parts (very deep blue - can't be ponds). Plus realizing this same situation is happening over most of the picture, with just some light clouds moderating colors in most areas of it. Those dark blue areas - were recently thinner, FYI ice pack parts, which now melted away. But the same melt which taken away those thinner parts - also melted much thickness of still-remaining ice, too, in the same time. Can't have one without the other. Which is why remaining ice has to be much thinner than in other areas of the CAB which don't have such (relatively) big open water bits.

This worrying melt process in big parts of the CAB was going on for quite a while already, as mentioned by me about one of sectors of Atlantic side of the CAB some ~15 days ago. Back then gentlemen here didn't pay too much attention to it. But now the damage is clearly visible, eh.

In this particular region, the pack was a mix of some MYI and FYI, yes. No doubt we see remains of some MYI here. But, note that none of this MYI is older than 3-years-old ice, i.e. nothing formed even as recently as 2013. So no super-thick fields were in the area to begin with, if you meant something like 4+ meters-thick 5+ years-old "strong" ice: this January, ice thickness in this region was 2.5...3 meters, as opposed to some 4...4.5 meters in some few places next to Greenland and in some parts of CAA.

Overall, very little of the pre-2012 "real thick MYI" is left in the Arctic those days, too: most of the CAB is the same deal as this particular region of it. Old logic "may be it's thick MYI here and it'll survive a LOT of melting momentum" becomes the thing of the past - quick.

Addendum: and no, this region was not "subjected to rough seas". It's 83...85 degrees North, so this whole region had and still has high-concentration ice for hundreds miles around it. For "rough sea" to break MYI, you gotta have real big open water area for big waves to form - thousands square miles of practically open water. No such region existed anywhere near this region, and still doesn't exist even now. Which is why i think it is mostly melt we see, - not wave action.
« Last Edit: July 13, 2017, 07:17:07 PM by F.Tnioli »

epiphyte

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Re: The 2017 melting season
« Reply #2819 on: July 13, 2017, 06:59:22 PM »
And one more:  broader view of the western Beaufort to the eastern ESS.


Lots of smoke. Complex implications, but going by the paper linked below,
 the upshot might be roughly:

- Right now, mostly over open water... -> ~-30W/m2 directly at the surface,
  but increased warming higher up, discouraging cloud formation.

- Where the smoke is over ice, decreased albedo raising the total heat budget.

... overall effect on melt progress? Who the f..k knows? I'd bet the models don't either   :-\

http://onlinelibrary.wiley.com/store/10.1029/2007JD009657/asset/jgrd14586.pdf;jsessionid=2E91B0BF9ABE8ADC3D936D1DF2AF8A7A.f01t04?v=1&t=j52nq0yq&s=a3441602405366faa277384a1a312dd2446a8e56
 http://onlinelibrary.wiley.com/store/10.1029/2007JD009657/asset/jgrd14586.pdf;jsessionid=2E91B0BF9ABE8ADC3D936D1DF2AF8A7A.f01t04?v=1&t=j52nq0yq&s=a3441602405366faa277384a1a312dd2446a8e56 : Going by


Thomas Barlow

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Re: The 2017 melting season
« Reply #2820 on: July 13, 2017, 07:15:48 PM »
If this sliver of green goes in the next week or two, and replaced by blue-purple (basically broken-up 1m ice), the situation becomes dynamic and unpredictable.

Compare the same area in 2016:
« Last Edit: July 13, 2017, 07:24:46 PM by Thomas Barlow »

bbr2314

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Re: The 2017 melting season
« Reply #2821 on: July 13, 2017, 08:11:36 PM »
       It seems to me that at some point in past melt seasons, Greenland and the CAA served as a sort of backstop for compaction. This area usually stayed protected from SST's longer, too. With Nares open and likely the CAA itself soon to be, not only will the "Garlic Press" be open, allowing for loss of ice from the CAB, but there is also bound to be less compaction. This will make a huge difference in the vulnerability of the ice late in the season.
        An army that is loosing a battle falls back and regroups in order to make best use of it's strength. The ice, though very much unwittingly, has done just the same in past seasons, allowing it to hold out longer. How will the late season be affected if the ice can't compact as well, perhaps even dispersing more? If the winds and currents try to compact it elsewhere, SST's might be a problem, at least for a moment.
I would think the Arctic fights back with an even bigger block of ice, i.e., Greenland. It has something like 145X the volume.

The melt season in Greenland has so far been muted by persistent cold and the albedo gains accumulated over the previous twelve months, but the question is whether that will continue through October with an Arctic ice pack that shrinks to its smallest area ever (IMO). A la 2012, this should focus more heat onto Greenland as the area of highest albedo continues to dwindle in relative size.

I anticipate a dramatic increase in Greenland melt as we enter August -> September -> October but we shall see if it actually happens. With the amount of moisture that will likely be available, winter's firm return in the far north + interior could easily be offset by vast plumes of coastal wetness that decimate the pack within a few hundred miles of shoreline. That may mean that while the sheer area of Greenland that sees melt remains lower than normal, the discharge could still increase to near-record or record levels.

magnamentis

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Re: The 2017 melting season
« Reply #2822 on: July 13, 2017, 08:24:35 PM »

just emphasizing one of my earlier points related to further development and predictions for this melting seasons, that all this rubble counts as 100% extent, most here know that of course but i think those images are very suitable example to illustrate the value of extent at this time of the year, basically it could even be half and still count 100% as extent which makes that number a poor indicator. last on this one from me this season, promised, except in reply to posts that try to ignore the fact. ;) in relation to observations and predictions to the further development of the melting season.
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Comradez

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Re: The 2017 melting season
« Reply #2823 on: July 13, 2017, 11:13:28 PM »
The latest installment of my worldview imagery analysis is up. 
https://youtu.be/trILWIAQc9E

Among other things, I look at the dramatic recent melt in the East Siberian Sea and compare it to recent years.  2017 appears to be clearly in the lead along the whole Russian sector of the Arctic. 

Neven

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Re: The 2017 melting season
« Reply #2824 on: July 13, 2017, 11:18:26 PM »
You can say that again, Comradez (nice video again, BTW).

Here's from Wipneus' AMSR2 thread:



And this animation:

« Last Edit: July 13, 2017, 11:39:35 PM by Neven »
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JayW

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Re: The 2017 melting season
« Reply #2825 on: July 14, 2017, 12:10:34 AM »
July 10-13, 72 hours of mesmerizing swirls north of Utqiagvik.

Imagery courtesy of the University of Alaska.
http://feeder.gina.alaska.edu
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Tor Bejnar

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Re: The 2017 melting season
« Reply #2826 on: July 14, 2017, 12:30:21 AM »
I wonder what a 'fluid dynamics' knowledgeable person would say about those pretty swirls, and especially their opinion about any vertical mixing associated with them.
Arctic ice is healthy for children and other living things.

VeliAlbertKallio

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Re: The 2017 melting season
« Reply #2827 on: July 14, 2017, 12:38:29 AM »
Very heavily pulverized sea ice 13.07.2017 set between Greenland / Svalbard / Franz Joseph Land and the North Pole. (Enhanced). Large 3D-surface area and the increases in the vertical mixing of the ocean by winds and waves must cause volume loss across this wide area that is feeding to the Fram Strait and to the Barents Sea. The countless leads also mop up sunlight near the Pole most efficiently. (The picture is best seen by clicking it to the full-screen view on and then again with magnification glass to see further details.) Enclosed close-up shows softness of the sea ice.
« Last Edit: July 14, 2017, 01:10:50 AM by VeliAlbertKallio »

oren

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Re: The 2017 melting season
« Reply #2828 on: July 14, 2017, 12:39:15 AM »
Thanks JayW for this instructive animation.
All this shite counts as extent. But not for long.

liefde

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Re: The 2017 melting season
« Reply #2829 on: July 14, 2017, 12:43:21 AM »
It really amazes me, that even some Veterans have Hopium for a Rebound Year.
Yes, it's almost irrational. With the brick loose from Larsen C I really think this was it; We'll *never* see higher extent globally anymore in our lives, or in human existence, even. That's a harsh realization, but it's a valid one. It's had its last chance a couple of days ago, but you can all see the pattern now;
https://sites.google.com/site/arctischepinguin/home/sea-ice-extent-area/grf/nsidc_global_extent_byyear_b.png
This was really it, guys.
It's bye bye to the ice-caps. There's no recovery plan that'll work or fix it in time. And knowing the relation of upcoming meltdown (pun intended) to the addition of excess CH4, it also means the countdown can begin within our generations. We'll be living with uninhabitable zones that have too high wet-bulb temperatures much sooner than expected.

Phil.

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Re: The 2017 melting season
« Reply #2830 on: July 14, 2017, 03:22:22 AM »
I wonder what a 'fluid dynamics' knowledgeable person would say about those pretty swirls, and especially their opinion about any vertical mixing associated with them.


Looks a bit like a von Karman vortex street.

http://cimss.ssec.wisc.edu/goes/blog/archives/113

Hyperion

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Re: The 2017 melting season
« Reply #2831 on: July 14, 2017, 03:34:43 AM »
Heres an animation of the 850hpa winds and temps predicted for the 5 days 14 july to 18 july. An assault from all fronts of high temp air at this level, and the ice running for (dubious) safety in the garlic press of the CAA.

Click to Animate.
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Hyperion

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Re: The 2017 melting season
« Reply #2832 on: July 14, 2017, 04:47:39 AM »
And heres the just above surface temperature and wind animation 14-18 July.

The all fronts push towards the Garlic Press seems even more evident here. The Mid Russian coastline gets a slight reprieve for a day or so in the middle with some onshore cold expulsion, but I doubt it will be enough to do more than push a few floes loose into a killing ground. Theres plenty of offshore winds with enough open sea fetch to generate considerable swells to pummel the edges of the pack off the Eurasian continent. But the sustained strong southerlies in the north, Bering and Chukchi seas are going to produce some very decent northbound swells.  And not only accelerate gulf stream and warm pacific waters into the basin, but mix warm Alaskan and Eurasian Riverine fluxes, and low salinity surface waters with the warm salty stuff incoming as it passes over the shallow continental shelf areas. Westerlies blowing strongly along the Bering coast a few days in will enhance both pacific influx and this mixing. This may well stop the pacific waters descending at all, and allow their heat to directly get at the pack. Possibly even carving a channel through nth of CAA and Greenland where that strip of late first year ice is.

Click to Animate
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Michael Hauber

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Re: The 2017 melting season
« Reply #2833 on: July 14, 2017, 07:50:58 AM »
Forecast looks on the cool side for much of the Arctic when compared to some recent years.  For 850hp the area at or below 0 degrees (corresponding to maybe 5-10 deg at surface) maintains coverage of a good healthy chunk of the central Arctic basin.  In previous big heatwaves I've seen the area below 0 pushed right out of the central Arctic basin into small fragments at the fringe. 
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Re: The 2017 melting season
« Reply #2834 on: July 14, 2017, 09:05:32 AM »
The big influxes of tropical water vapour have been keeping the 850hpa altitude generally much warmer than near the surface. And the salty ice slush over most of the basin has a more powerful cooling effect as its unprecedented surface area exposed to water and air takes up energy as it melts in place. Easy to elevate surface temps if you have a largely smooth unbroken sheet that has little capacity to absorb energy from the air.
When you look at the 250hpa Jet situation below, you get an idea of how profound and complex  the atmospheric mixing has become. And over 30km up at the 10hpa level we have a planet wide movement of air from the north polar region to the south pole, creating a east to west trade winds belt covering the entire northern hemisphere, and a powerful up to over 400kmph west to east belt covering most of the southern hemisphere where the flow is continuing south. The only place that is warmer at 18km altitude than 12km is the south pole. The tropopause transition to the stratosphere seems to have lifted planet wide. There appears to be a big thrust of tropical moisture northwards planet wide from the returning airflow descending from high altitude over the south pole. I've attached a still of this situation with 10hpa winds and TPW worldwide.

The last two below are gifs of Total Precipitable water 14-18 july. click to animate
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F.Tnioli

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Re: The 2017 melting season
« Reply #2835 on: July 14, 2017, 11:39:45 AM »
... The countless leads also mop up sunlight near the Pole most efficiently. ...
Obviously, yes. July is high insolation month, and lots of CAB now takes it head-on. Combined with lesser thickness in many places, this is nothing short of catastrophic development in me book, especially if it would last in significant proportions for mere 1 more week. Any clues whether it would, Veli?

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Re: The 2017 melting season
« Reply #2836 on: July 14, 2017, 01:42:08 PM »
NSIDC SIE Daily
x 106 km2

2017,    07,  12,      8.274
2017,    07,  13,      8.075

Down 199k km2

pauldry600

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Re: The 2017 melting season
« Reply #2837 on: July 14, 2017, 02:38:42 PM »
Aww so close to a double

Anyways a lot of the easy ice of past few days melted in the past 3 so now it may take more work to melt the next sections.

So even if we get another century i forsee some 60 to 80k  melts in the offing and then perhaps a few more centuries

romett1

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Re: The 2017 melting season
« Reply #2838 on: July 14, 2017, 03:03:14 PM »
NSIDC SIE Daily
x 106 km2

2017,    07,  12,      8.274
2017,    07,  13,      8.075

Down 199k km2

Down 516,000 km² in just 72 hours.



F.Tnioli

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Re: The 2017 melting season
« Reply #2839 on: July 14, 2017, 03:12:08 PM »
...
Anyways a lot of the easy ice of past few days melted in the past 3 so now it may take more work to melt the next sections. ...
Normally, that would be true. But we are going through this "soup" season here, as i call it. All bets are off.

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Re: The 2017 melting season
« Reply #2840 on: July 14, 2017, 04:08:30 PM »
To illustrate my above point,



This is yesterday, 82° North - CAB proper. Completely open water area around the white cross (coordinates are given) - is ~4 km radius. I.e. it's ~4 km from the middle of the cross to any big ice piece. So, wave action increasingly becomes a factor in such locations. Data i have suggests there are some even much wider 100% open water areas above 85° North right now, too.

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Re: The 2017 melting season
« Reply #2841 on: July 14, 2017, 04:12:09 PM »
Aww so close to a double

Anyways a lot of the easy ice of past few days melted in the past 3 so now it may take more work to melt the next sections.

So even if we get another century i forsee some 60 to 80k  melts in the offing and then perhaps a few more centuries

without naming a final point in time this prediction certainly becomes true ;)

60-80ies i can't think of while everything always remains possible. IMO the question will be whether we shall see the usual series of centuries or a few doubles above what we've encountered in previous years. more doubles will certainly happen, question is whether it will happen now or not because the extremes are wheather related.
« Last Edit: July 14, 2017, 10:55:54 PM by magnamentis »
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NeilT

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Re: The 2017 melting season
« Reply #2842 on: July 14, 2017, 04:34:34 PM »
Talking about extent stalling, I do wonder whether it will continue for a while longer.  Given the state of some of the area covered in >15% ice.









These are all places where extent will continue to decline.  Area?  Not so much as the open water is already included.

Whilst this continues, the CAB itself will continue to change.  Whether it compacts and firms up or whether it is torn further apart, remains to be seen.
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Re: The 2017 melting season
« Reply #2843 on: July 14, 2017, 04:43:03 PM »
Number of doubles by year after July 13 (NSIDC)

2007 - 0

2011 - 0
2012 - 2 (both in August)
2013 - 1
2014 - 0
2015 - 1
2016 - 2 (but with a plus 12 in between the two minus 200 days
2017 - ?

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Re: The 2017 melting season
« Reply #2844 on: July 14, 2017, 05:33:37 PM »
...
Anyways a lot of the easy ice of past few days melted in the past 3 so now it may take more work to melt the next sections. ...
Normally, that would be true. But we are going through this "soup" season here, as i call it. All bets are off.
Concur.

Based on the fragmented state of the ice, and how much late, thin FYI is woven through the pack, the melt season is playing out much as I'd imagined.

What remains to be seen is if weather and the break we got from additional snow cover will rescue the pack  from a new low.

I think it possible we might find ourselves in a unique place in September. I think it possible we may still see a new low in area, but may not have one in extent.
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Re: The 2017 melting season
« Reply #2845 on: July 14, 2017, 07:56:48 PM »
Following this as close as I did for years now. However, I'm going to enjoy a short holiday. When I'm back, I expect to see what I've been forecasting for almost two years.
MODIS 13/07 perfectly shows what Wipneus published today in the 'Extent' thread. Wrangell Island is practically cleared now. the state of the pack in that sector is horrible.
Daily Composites shows that temp anomaly in that sector was worse than '16 all May-today. The seas out there will clear in a linear fashion until the 15% border will have passed the '07 minimum within weeks.
I still expect this will become a new minimum season.
Even though the Atlantic doesn't seem to co-operate...

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Re: The 2017 melting season
« Reply #2846 on: July 14, 2017, 08:46:38 PM »
werther,
Even though the Atlantic doesn't seem to co-operate...

SST's are building up off the front on the Atlantic side now and will probably change things there soon enough.

One surface chart and one chart for 5 meters down. Both just off FJL
« Last Edit: July 14, 2017, 08:53:43 PM by Tigertown »

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Re: The 2017 melting season
« Reply #2847 on: July 14, 2017, 10:00:08 PM »
...
Anyways a lot of the easy ice of past few days melted in the past 3 so now it may take more work to melt the next sections. ...
Normally, that would be true. But we are going through this "soup" season here, as i call it. All bets are off.
Concur.

Based on the fragmented state of the ice, and how much late, thin FYI is woven through the pack, the melt season is playing out much as I'd imagined.

What remains to be seen is if weather and the break we got from additional snow cover will rescue the pack  from a new low.

I think it possible we might find ourselves in a unique place in September. I think it possible we may still see a new low in area, but may not have one in extent.

One thing I've seen in particular this season is that regardless of how fragmented it is, its durability is heavily influenced by thickness. You can have ice like the Beaufort Gyre (or south Hudson Bay) that sticks along despite constant heat and warm(er) waters. 

Then you have ice that just starts to break apart on its own even mid-pack, which is much thinner... thickness is hard to see from worldview (unlike fragmentation), but it makes a big difference.

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Re: The 2017 melting season
« Reply #2848 on: July 14, 2017, 10:21:05 PM »
One week change (sorry for the amateurish gif  :o ):
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Re: The 2017 melting season
« Reply #2849 on: July 14, 2017, 10:36:15 PM »
Following this as close as I did for years now. However, I'm going to enjoy a short holiday. When I'm back, I expect to see what I've been forecasting for almost two years.
MODIS 13/07 perfectly shows what Wipneus published today in the 'Extent' thread. Wrangell Island is practically cleared now. the state of the pack in that sector is horrible.
Daily Composites shows that temp anomaly in that sector was worse than '16 all May-today. The seas out there will clear in a linear fashion until the 15% border will have passed the '07 minimum within weeks.
I still expect this will become a new minimum season.
Even though the Atlantic doesn't seem to co-operate...
Expanding on what Werther has said, as an illustration of what I (and I think he) expect to see starting to develop across the basin.

Two weeks in the Kara Sea.

<click to animate>
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