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Messages - slow wing

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1
Arctic sea ice / Re: The 2018 melting season
« on: Today at 05:22:38 AM »
U. Bremen's false colour ice concentration maps show a week's action in the Arctic basin, ending on the map just released, 2018-09-20...

2
Arctic sea ice / Re: The 2018 melting season
« on: September 20, 2018, 05:19:38 AM »
U. Bremen's false colour ice concentration maps show a week's action in the Arctic basin, ending on the map just released, 2018-09-19...

3
Arctic sea ice / Re: The 2018 melting season
« on: September 19, 2018, 07:50:04 AM »
U. Bremen's false colour ice concentration maps show a week's action in the Arctic basin, ending on the map just released, 2018-09-18...

4
Arctic sea ice / Re: The 2018 melting season
« on: September 18, 2018, 07:02:53 AM »
U. Bremen's false colour ice concentration maps show a week's action in the Arctic basin, ending on the map just released, 2018-09-17...

5
Arctic sea ice / Re: The 2018 melting season
« on: September 17, 2018, 05:12:33 AM »
U. Bremen's false colour ice concentration maps show a week's action in the Arctic basin, ending on the map just released, 2018-09-16...

6
Arctic sea ice / Re: The 2018 melting season
« on: September 16, 2018, 05:39:50 AM »
Oren, yes, I think it is just the ice winking in and out.

There's a large region of slush around the ESS that must be at the edge of being called ice.

Some musing on measurements & definitions...

Presumably the definitions for extent and area won't be of any fundamental physical significance. Instead, there's an algorithm processing the input data & it has a threshold for whether to include each area element. Whether e.g. a region of wet slush is counted depends on the instruments and on the algorithm in a way that is not physically simple. That's fine, presuming the answer obtained is somewhat reasonable, and the answer is consistently applied for each new day. It then gives a somewhat reasonable measure for how the extent and area are progressing.

In contrast, it should be possible to define volume in a more physical way. For example, it could be defined in proportion to the weight of water (typically ice and snow) that extends above the water level for liquid water. The total volume is then obtained by summing up the weight-per-unit-area over the defined Arctic region. That gives a simple physical understanding. The measured value would of course still be an experimentally extracted approximation to that simple physical definition.

  With this wonderful new satellite they are about to put up, which gives very accurate height measurements, a very simple physical definition would be a sum/integral of the heights above local sea level - then converting to a volume of ice using either a single constant for ice density or else using locally estimated densities after attempting to estimate the ice/snow/melt pond mix.
Again, that's a physically simple approach to measuring the ice volume/mass.


This is not my field though. Is that fair comment? Is that how e.g. the PIOMAS definition of volume is extracted in practice?

7
Arctic sea ice / Re: The 2018 melting season
« on: September 16, 2018, 05:11:50 AM »
U. Bremen's false colour ice concentration maps show a week's action in the Arctic basin, ending on the map just released, 2018-09-15...

8
Arctic sea ice / Re: The 2018 melting season
« on: September 16, 2018, 05:10:47 AM »
Any theories as to why the floating patch of ice remains? Was the piling up creating thicker ice?
Yes.

9
Arctic sea ice / Re: The 2018 melting season
« on: September 16, 2018, 03:06:44 AM »
Worldview captured a clear view of the remaining sea ice off the Alaskan coast.

There's not much left of the persistent ice patch that originated from ice piling up against the coast during the freezing season.

10
Arctic sea ice / Re: The 2018 melting season
« on: September 15, 2018, 12:49:18 PM »
Oren, it's around zero degrees and windy in the ESS at the moment and that is predicted to continue over at least the next couple of days. So freeze-up looks unlikely just yet in the ESS.

11
Arctic sea ice / Re: The 2018 melting season
« on: September 15, 2018, 07:30:49 AM »
U. Bremen's false colour ice concentration maps show a week's action in the Arctic basin, ending on the map just released, 2018-09-14...

12
Arctic sea ice / Re: The 2018 melting season
« on: September 14, 2018, 05:22:16 AM »
U. Bremen's false colour ice concentration maps show a week's action in the Arctic basin, ending on the map just released, 2018-09-13...

13
Arctic sea ice / Re: The 2018 melting season
« on: September 13, 2018, 06:25:07 AM »
U. Bremen's false colour ice concentration maps show a week's action in the Arctic basin, ending on the map just released, 2018-09-12...

14
Arctic sea ice / Re: The 2018 melting season
« on: September 12, 2018, 05:18:47 AM »
U. Bremen's false colour ice concentration maps show a week's action in the Arctic basin, ending on the map just released, 2018-09-11...

15
Arctic sea ice / Re: The 2018 melting season
« on: September 11, 2018, 05:23:06 AM »
U. Bremen's false colour ice concentration maps show a week's action in the Arctic basin, ending on the map just released, 2018-09-10...

16
Arctic sea ice / Re: 2018 sea ice area and extent data
« on: September 10, 2018, 05:52:43 AM »
Wonderful! Thanks for posting, tvansant.

A couple of snippets...


Nathan Kurtz, NASA Goddard
"What I’m really excited to see are the month-to-month changes in sea ice thickness, because we didn’t have that with the first ICESat..."

"..right now there’s a lot of assumptions made about how snow accumulates on the ice over the year. With ICESat-2, we should be able to see things like the effect of a passing storm."


Thorsten Markus, NASA Goddard
"What I’m really most excited about is seeing these data come in at such a high resolution...
Over sea ice you’ll see all these gaps and ridges, and discover just how rough that remote ice is."

17
Arctic sea ice / Re: The 2018 melting season
« on: September 10, 2018, 05:44:23 AM »
U. Bremen's false colour ice concentration maps show a week's action in the Arctic basin, ending on the map just released, 2018-09-09...

18
Arctic sea ice / Re: The 2018 melting season
« on: September 09, 2018, 07:47:12 AM »
U. Bremen's false colour ice concentration maps show a week's action in the Arctic basin, ending on the map just released, 2018-09-08...

19
Arctic sea ice / Re: The 2018 melting season
« on: September 08, 2018, 06:09:42 AM »
U. Bremen's false colour ice concentration maps show a week's action in the Arctic basin, ending on the map just released, 2018-09-07...

20
Arctic sea ice / Re: The 2018 melting season
« on: September 07, 2018, 05:18:46 AM »
U. Bremen's false colour ice concentration maps show a week's action in the Arctic basin, ending on the map just released, 2018-09-06...

21
Arctic sea ice / Re: The 2018 melting season
« on: September 06, 2018, 07:07:08 AM »
U. Bremen's false colour ice concentration maps show a week's action in the Arctic basin, ending on the map just released, 2018-09-05...

22
Arctic sea ice / Re: The 2018 melting season
« on: September 05, 2018, 05:15:25 AM »
U. Bremen's false colour ice concentration maps show a week's action in the Arctic basin, ending on the map just released, 2018-09-04...

23
Arctic sea ice / Re: The 2018 melting season
« on: September 04, 2018, 06:49:54 AM »
U. Bremen's false colour ice concentration maps show a week's action in the Arctic basin, ending on the map just released, 2018-09-03...

24
Arctic sea ice / Re: The 2018 melting season
« on: September 01, 2018, 05:26:00 AM »
U. Bremen's false colour ice concentration maps show a week's action in the Arctic basin, ending on the map just released, 2018-08-31...

25
Arctic sea ice / Re: The 2018 melting season
« on: August 31, 2018, 07:15:31 AM »
U. Bremen's false colour ice concentration maps show a week's action in the Arctic basin, ending on the map just released, 2018-08-30...

26
Arctic sea ice / Re: The 2018 melting season
« on: August 30, 2018, 05:19:35 AM »
U. Bremen's false colour ice concentration maps show a week's action in the Arctic basin, ending on the map just released, 2018-08-29...

27
Arctic sea ice / Re: The 2018 melting season
« on: August 29, 2018, 05:53:30 AM »
U. Bremen's false colour ice concentration maps show a week's action in the Arctic basin, ending on the map just released, 2018-08-28...

28
Arctic sea ice / Re: The 2018 melting season
« on: August 28, 2018, 05:24:01 AM »
U. Bremen's false colour ice concentration maps show a week's action in the Arctic basin, ending on the map just released, 2018-08-27...

29
Arctic sea ice / Re: The 2018 melting season
« on: August 27, 2018, 05:38:24 AM »
U. Bremen's false colour ice concentration maps show a week's action in the Arctic basin, ending on the map just released, 2018-08-26...

30
Arctic sea ice / Re: The 2018 melting season
« on: August 26, 2018, 05:24:34 AM »
Today, Aug 25, is one of the dates shown on Neven's year-to-year ice concentration map comparison.

It's easy to forget that, for the most recent two previous years, 2016 and 2017, the ice on this date was in bad shape for close to the North Pole and on the Russian side.

This year, 2018, the ice is compact on the Atlantic side but spread out on the Pacific side. Low atmospheric pressure is expected to begin to dominate within the next day or so, bringing some moderately strong winds. How much of the Pacific-side ice debris will that clean up?

31
Arctic sea ice / Re: The 2018 melting season
« on: August 26, 2018, 05:11:51 AM »
U. Bremen's false colour ice concentration maps show a week's action in the Arctic basin, ending on the map just released, 2018-08-25...

32
Arctic sea ice / Re: The 2018 melting season
« on: August 25, 2018, 06:01:00 AM »
U. Bremen's false colour ice concentration maps show a week's action in the Arctic basin, ending on the map just released, 2018-08-24...

33
Arctic sea ice / Re: The 2018 melting season
« on: August 24, 2018, 05:50:55 AM »
U. Bremen's false colour ice concentration maps show a week's action in the Arctic basin, ending on the map just released, 2018-08-23...

34
Arctic sea ice / Re: The 2018 melting season
« on: August 23, 2018, 01:43:38 PM »
I think this is partially an illusion of clouds.

The other 2 satellites show the same shape against different cloud backgrounds.

35
Arctic sea ice / Re: The 2018 melting season
« on: August 23, 2018, 09:22:15 AM »
After a couple of weeks of relentless Southerly winds from a warm Laptev Sea, the edge of the ice pack here is a smoothly curving line with no structure from individual ice floes.

36
Arctic sea ice / Re: The 2018 melting season
« on: August 23, 2018, 05:22:37 AM »
U. Bremen's false colour ice concentration maps show a week's action in the Arctic basin, ending on the map just released, 2018-08-22...

37
Arctic sea ice / Re: The 2018 melting season
« on: August 22, 2018, 05:24:23 AM »
U. Bremen's false colour ice concentration maps show a week's action in the Arctic basin, ending on the map just released, 2018-08-21...

38
Arctic sea ice / Re: The 2018 melting season
« on: August 21, 2018, 05:57:30 AM »
U. Bremen's false colour ice concentration maps show a week's action in the Arctic basin, ending on the map just released, 2018-08-20...

39
Arctic sea ice / Re: The 2018 melting season
« on: August 18, 2018, 07:37:45 AM »
Quote

The U. Bremen site that I had been using previously has been down for several days. Do we know why and have the reasons been posted here?
Always assume nefarious intent from the usual suspects. Of course I don't have proof they had to move it for disorderly behavior. Politics is not science so I suggest take these insinuating questions elsewhere.
I don't understand that response at all. It was a straight question and it related only to the science, not to politics. I don't know the reasons and asked for them only as a way to help determine how long the site and data is likely to be down for.

At the discretion of anyone who knows, they are of course welcome to instead answer that directly: how long are the site and data likely to be down for? That is what is directly relevant to me and to this thread as I had been posting images sourced from there every day on this thread.

40
Arctic sea ice / Re: The 2018 melting season
« on: August 18, 2018, 01:22:32 AM »
NSIDC ice concentration maps show a week's action in the Arctic basin, ending on the map most recently released, 2018-08-16 - see first figure.

There is a low concentration region showing that, if it happened to melt out completely, would snip off the corner of the main ice pack that extends into the Beaufort Sea. Presumably too late in the season for that though. Rather than the ice melting out, the low concentration region has presumably arisen largely from the ice floes there being separated by winds from the low pressure system currently in the CAA - as shown in the second figure.

The U. Bremen site that I had been using previously has been down for several days. Do we know why and have the reasons been posted here?

41
Arctic sea ice / Re: The 2018 melting season
« on: August 15, 2018, 08:18:53 AM »
U. Bremen's false colour ice concentration maps show a week's action in the Arctic basin, ending on the map just released, 2018-08-14...

42
Arctic sea ice / Re: The 2018 melting season
« on: August 14, 2018, 05:07:46 AM »
U. Bremen's false colour ice concentration maps show a week's action in the Arctic basin, ending on the map just released, 2018-08-13...

43
Arctic sea ice / Re: The 2018 melting season
« on: August 13, 2018, 06:40:38 AM »
After a cloudy July, the Arctic sea ice on the Russian side has suffered under two weeks of high atmospheric pressure and the clear skies that brings.

The ice north of the Laptev Sea, in particular, has also wilted under southerly winds carrying heat from the Siberian land mass.

With that high pressure system expected to finally be displaced by a low pressure system arriving from the Kara Sea, soon the Siberian heat should instead be steered towards the large sea ice lobe that extends southwards into the Eastern Siberian Sea.

That prediction is illustrated below with a earth.nullschool.net 48 hour forecast.

As I understand it, we're transitioning into the late stage of the melt season where exposure to heat and salt in the water becomes more important to melting the sea ice than direct heat from sunlight or winds. Therefore, the predicted arrival of low pressure and relatively strong winds to stir things up, will probably be conducive to a continuation of strong melting in the middle part of August.

44
Arctic sea ice / Re: The 2018 melting season
« on: August 13, 2018, 06:03:25 AM »
U. Bremen's false colour ice concentration maps show a week's action in the Arctic basin, ending on the map just released, 2018-08-12...

45
Arctic sea ice / Re: The 2018 melting season
« on: August 12, 2018, 05:23:33 AM »
U. Bremen's false colour ice concentration maps show a week's action in the Arctic basin, ending on the map just released, 2018-08-11...

46
Arctic sea ice / Re: The 2018 melting season
« on: August 11, 2018, 05:39:23 AM »
U. Bremen's false colour ice concentration maps show a week's action in the Arctic basin, ending on the map just released, 2018-08-10...

47
[4.25,4.75]. Just went up 0.25 from my daily minimum prediction, which I explained in more detail.

48
I voted the [4.00-4.50] million square km bin.

I like the ice movement vector display for today as probably providing a good proxy for where the ice will remain. I'm guessing the ice shown in white will probably remain while that in light blue will probably go.

To set the scale, the area of the circle for 80 degrees latitude is approximately pi*(10,000/9)^2 km^2 ~ 3.9 million square km. (The Earth's curvature has been ignored.)

Just eye-balling, the area of white ice is similar to that area. I think a bit of the light blue ice might remain in the ESS. Hence the bin [4.00,4.50].

If I had to guess the year rank, I think this year will end up in fourth place. Reading off from the opening post, and in units of million square km:
3.18 2012 1st
4.02 2016 2nd
4.07 2007 3rd
[2018 may go here]
4.26 2015
4.27 2011
4.47 2017
...







49
Arctic sea ice / Re: The 2018 melting season
« on: August 10, 2018, 06:58:17 AM »
U. Bremen's false colour ice concentration maps show a week's action in the Arctic basin, ending on the map just released, 2018-08-09...

50
Arctic sea ice / Re: The 2018 melting season
« on: August 09, 2018, 06:41:45 AM »
U. Bremen's false colour ice concentration maps show a week's action in the Arctic basin, ending on the map just released, 2018-08-08...

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