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Author Topic: 2019 sea ice area and extent data  (Read 250564 times)

Pagophilus

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Re: 2019 sea ice area and extent data
« Reply #1300 on: June 24, 2019, 06:33:02 AM »

Pragma, thank you.  But all the credit has to go to the NSIDC, they can be obtained here:

http://nsidc.org/arcticseaicenews/sea-ice-comparison-tool/

I think they are amazing too, and I am glad to bring them before this forum if they have not previously around.

LOL! I'm laughing and embarrassed. As I have mentioned before, NSIDC is updating their tools all the time and are very receptive to suggestions.

I was going to email them, suggesting a comparison tool.  :-[

Um, er ... never mind  :)

Not at all -- it was a completely natural mistake -- although if you knew how limited my programming skills are you would not have made it.   I myself just stumbled upon these comparison maps.  I had never seen anyone use them here, so I felt like someone pulling out a clamshell phone at an Apple convention, until you kindly responded. 

binntho

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Re: 2019 sea ice area and extent data
« Reply #1301 on: June 24, 2019, 07:28:19 AM »
Like many another, I have been wondering why extent losses have dropped so slowly.  I think much of the reason may lie in the Barentz Sea.  Two tongues of ice have been projecting into the Barentz for some time, as the ice pack rotated away from the Pacific side and towards the Atlantic side, an unusual move.  One tongue projects between Svalbard and FJL and one between FJL and SZ.

The initial reaction was that this ice had gone to 'oblivion', into the 'killing zone', and I too was of that opinion.  In fact the ice tongues have been remarkably persistent (see the first comparative NSIDC map below, comparing June 8 and 22 this year). 

June has been quite cloudy over those two tongues so estimating drift speed of the ice is a bit tricky, but a recognizable structure in the esternmost tongue seems to drift 40 km between June 12th and June 21st. In the westernmost tongue, a recognizable structure drifts some 100 km between the two days.

So the ice in those tongues is drifting southwards, but the tongues themselves are not growing, hence a lot of melting melting is happening (as expected). The tongues themselves also show a lot of internal melting, i.e. the ice is becoming more dispersed and "sludge" like, with thin melting streamers even inside the tongues themselves.

Rich

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Re: 2019 sea ice area and extent data
« Reply #1302 on: June 24, 2019, 07:43:27 AM »
It is reasonable, to remark when statements in in other threads , e.g. "Panzer divisions" (not my phrase) fail to mobilise and Friv's extravagant forecasts do not materialise in or seem justified by changes in the area and extent data so far. "Looks like it's going to [be] pretty soon that sailing from Pacific to Atlantic w/o an ice breaker. Perhaps June."(NOT one of Frivs)  is a candidate for the future.

In defense of Friv, I would say that the recent loss of  > 1m km2 of area in a week was an example of very high melt which he had foreshadowed prior to it's occurrence.

In defense of myself as the person who made the comment about the open water from the Pacific to Atlantic.  I would ask you to look at the northern sea route and ask you if there is any segment which you obviously think is going to survive beyond June?

Lotta folks here complaining about this thread being derailed by non-data, but that starts with you.

If you want to express your contempt of what I am posting on the melting thread, it would be nice if you could post your criticism there so I can reply and the readers of the extent and data thread don't have to read the discussion.

<I agree that if Gerontocrat wants to remark on other people's remarks, it's better to do it where the remarks were made, but this is the last of the meta-discussion I'm going to allow here. Gerontocrat can have the last word if he wants; N.>
« Last Edit: June 24, 2019, 08:38:44 AM by Neven »

Neven

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Re: 2019 sea ice area and extent data
« Reply #1303 on: June 24, 2019, 08:03:45 AM »
These are excellent maps. Thanks for taking the time, and I hope they become a regular feature on this thread.

Agreed, but they fit even better in the melting season thread.
Il faut comparer, comparer, comparer, et cultiver notre jardin

weatherdude88

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Re: 2019 sea ice area and extent data
« Reply #1304 on: June 24, 2019, 01:58:28 PM »
Looking at the raw daily data, 2019 NSIDC sea ice area is now the fifth lowest value in the data set. For 6.23, the daily value is 7,787,023 kilometers squared. There was a loss of 102,855 kilometers squared from the previous date.

2019 now has 236,390 kilometers squared more than 2012, 32,029 kilometers squared more than 2010, 9,356 kilometers squared more than 2007, and 8,144 more than 2016.

edit: gerontocrat was able to answer my question on the Central Arctic sea disparity for the sub 2008 data set. For my posts on 2007 sea ice area, I should of been adding 310,000 kilometers squared to the final value when all seas had been added for the pole hole adjustment.
« Last Edit: Today at 03:18:34 AM by weatherdude88 »

weatherdude88

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Re: 2019 sea ice area and extent data
« Reply #1305 on: June 24, 2019, 02:09:53 PM »
UH AMSR2 data is showing more high latitude sea ice extent and area in the arctic basin, than the highest melt years.


UH AMSR2 CAB extent


UH AMSR2 CAB area
« Last Edit: June 24, 2019, 04:36:57 PM by weatherdude88 »

Pagophilus

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Re: 2019 sea ice area and extent data
« Reply #1306 on: June 24, 2019, 04:33:11 PM »
Like many another, I have been wondering why extent losses have dropped so slowly.  I think much of the reason may lie in the Barentz Sea.  Two tongues of ice have been projecting into the Barentz for some time, as the ice pack rotated away from the Pacific side and towards the Atlantic side, an unusual move.  One tongue projects between Svalbard and FJL and one between FJL and SZ.

The initial reaction was that this ice had gone to 'oblivion', into the 'killing zone', and I too was of that opinion.  In fact the ice tongues have been remarkably persistent (see the first comparative NSIDC map below, comparing June 8 and 22 this year). 

June has been quite cloudy over those two tongues so estimating drift speed of the ice is a bit tricky, but a recognizable structure in the esternmost tongue seems to drift 40 km between June 12th and June 21st. In the westernmost tongue, a recognizable structure drifts some 100 km between the two days.

So the ice in those tongues is drifting southwards, but the tongues themselves are not growing, hence a lot of melting melting is happening (as expected). The tongues themselves also show a lot of internal melting, i.e. the ice is becoming more dispersed and "sludge" like, with thin melting streamers even inside the tongues themselves.

I agree wholeheartedly.  For the Arctic overall, this export of ice to the Barentz involves net loss of ice, period.  However, I think the ice is melting slower than one might expect, because so much ice has entered the Barentz, chilling the top layer of (now fresher) water.   Your observation that the Barentz has been cloudy over the past few weeks is another factor, I think, in reducing the rate of melting.

This Barentz sea ice will melt out (maybe soon, but the tongues are persistent) and there will be less ice in the CAB, so the medium and longer term prospects for the ice are troubling.


Pagophilus

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Re: 2019 sea ice area and extent data
« Reply #1307 on: June 24, 2019, 04:35:46 PM »
These are excellent maps. Thanks for taking the time, and I hope they become a regular feature on this thread.

Agreed, but they fit even better in the melting season thread.

Done!

Pragma

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Re: 2019 sea ice area and extent data
« Reply #1308 on: June 24, 2019, 05:39:32 PM »
These are excellent maps. Thanks for taking the time, and I hope they become a regular feature on this thread.

Agreed, but they fit even better in the melting season thread.

As they are of comparative extent data, I'm curious why you think so.

Not a  big deal, but I can see equally why they could be in either.

I ask because I post in threads and then second guess myself as to whether it is OT or not.

OT drift is easy, and usually unintentional.

cognitivebias2

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Re: 2019 sea ice area and extent data
« Reply #1309 on: June 24, 2019, 05:44:38 PM »
UH AMSR2 data is showing more high latitude sea ice extent and area in the arctic basin, than the highest melt years.

...

dude,
  Can you give us the correlation between CAB area/extent now and at minimum? 

I just ask because, as counterpoints go, this one feels a bit strained.

Neven

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Re: 2019 sea ice area and extent data
« Reply #1310 on: June 24, 2019, 07:41:32 PM »
As they are of comparative extent data, I'm curious why you think so.

Because graphs are a better representation of data than maps, but maps are a better visual representation of what goes on where during the melting season. Sometimes the threads overlap, but on the whole, I feel like this is the thread for graphs and maps go into the melting season thread.
Il faut comparer, comparer, comparer, et cultiver notre jardin

Shared Humanity

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Re: 2019 sea ice area and extent data
« Reply #1311 on: June 24, 2019, 07:43:10 PM »
too much meta discussion...

forkyfork

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Re: 2019 sea ice area and extent data
« Reply #1312 on: June 24, 2019, 08:32:04 PM »
UH AMSR2 data is showing more high latitude sea ice extent and area in the arctic basin, than the highest melt years.

...

dude,
  Can you give us the correlation between CAB area/extent now and at minimum? 

I just ask because, as counterpoints go, this one feels a bit strained.
i see years with higher area/extent than now which had a low minimum as well as vice versa

b_lumenkraft

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Re: 2019 sea ice area and extent data
« Reply #1313 on: June 24, 2019, 08:39:38 PM »
too much meta discussion...

+1

Please take the discussions about the data to the melting thread. This is the thread for the data. This is not for discussions about the data.

be cause

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Re: 2019 sea ice area and extent data
« Reply #1314 on: June 24, 2019, 09:44:03 PM »
I'm beginning to think that the unnecessary abuse of Gerontocrat and this thread has relieved us of one of our most valuable posters . b.c.
2007 + 5 = 2012 + 4 = 2016 + 3 = 2019 ...

Juan C. García

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Re: 2019 sea ice area and extent data
« Reply #1315 on: Today at 05:43:32 AM »
[ADS NIPR VISHOP (JAXA)] Arctic Sea Ice Extent.
 
June 24rd, 2019:
     9,597,909 km2, a drop of -60,652 km2.
     2019 is now 6th lowest on record.
     (2012 highlighted).
Which is the best answer to Sep-2012 ASI lost (compared to 1979-2000)?
50% [NSIDC Extent] or
73% [PIOMAS Volume]

Volume is harder to measure than extent, but 3-dimensional space is real, 2D's hide ~50% thickness gone.
-> IPCC/NSIDC trends [based on extent] underestimate the real speed of ASI lost.

gerontocrat

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Re: 2019 sea ice area and extent data
« Reply #1316 on: Today at 09:13:56 AM »
JAXA ARCTIC EXTENT :-  9,597,909 km2(June 24, 2019)

- Extent is 5th 6th lowest in the satellite record.
- Extent loss on this day 61 k, 16 k less than the average loss on this day of 77 k.
- Extent loss from maximum 4,673 k, 134 k (3.0 %) greater than the average of 4,539 k loss from maximum by this day,
- On average 45.9% of the melting season done, with 81 days to average date of minimum (13 September).

The Perils of Projections.
Average remaining melt would give a minimum of 4.26 million km2, 4th lowest in the satellite record, and 1.08 million km2 above the 2012 low of 3.18 million km2.
Looking at the last 5 years average remaining melt gives a result of 4.36 million km2, 6th lowest, and 1.18 million km2 above 2012.

Other Stuff

Until the weekend GFS showing  temperature anomalies at +0.9 to +1.9 degrees celsius. During this time the images suggest high +ve anomalies in central and eastern Siberia, with contrasting and sometimes strong -ve anomalies for most of the time on land and coastal sea by and in the Beaufort/CAA and Western Siberia, and in contrast again mostly +ve anomaly over most of the Arctic Ocean.

Over the weekend the picture changes somewhat. By Monday the CAA gets warmer, NW Canada and Alaska get a lot colder, and on the Russian side warmth moves west into areas bordering the Laptev and Kara, while the ESS area switches from strong warmth to a cold snap. However, over the Arctic Ocean itself there is a modest +ve  temp anomaly. Overall the Arctic temp anomaly stays well below 1 degree celsius.

A complicated picture.

We are now entering the period of maximum daily extent loss that lasts until mid or late July and then very gradually declines.
Apart from 2 days, over the last 3 weeks and more extent loss has been below or well below average.
_____________________________________________________________________
The volume data for June should be available by late next week. It will be interesting to see what has happened to volume and perhaps more importantly, thickness during this month.
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