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Author Topic: Home brew AMSR2 extent & area calculation  (Read 1558864 times)

Ninebelowzero

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Re: Home brew AMSR2 extent & area calculation
« Reply #2300 on: July 13, 2016, 10:52:33 AM »
.....The grainy appearance of this rubble is probably an indication that it consists of the disintegrating parts of thick ice, which supports the earlier assessment of PIOMASS of that region



Rubble is a word usually reserved for describing destroyed brickwork or fragmented stone and might translate badly. Detritus or a similar word with a wider generic use would be better here if needed at all.

Rob Dekker

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Re: Home brew AMSR2 extent & area calculation
« Reply #2301 on: July 13, 2016, 11:07:27 AM »
Side by side animation of Laptev sea ice concentration 2014 and 2016. In 2014 ice cover Laptev declined faster than all years in my limited database. 

No doubt, Wipneus. Laptev is definitively melting out slower than prior years.
In fact, the Laptev may be the only area outside of the CAB that shows significant resistance during the 2016 melting season.
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Pi26

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Re: Home brew AMSR2 extent & area calculation
« Reply #2302 on: July 13, 2016, 12:41:49 PM »
I think in the next 2-3 weeks the developement within the area between 70-83N from 160W to 110E is very important. Currently I mean there is good extend but too less volume.
« Last Edit: July 13, 2016, 12:58:07 PM by Pi26 »

Jim Pettit

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Re: Home brew AMSR2 extent & area calculation
« Reply #2303 on: July 13, 2016, 01:07:45 PM »
Rubble is a word usually reserved for describing destroyed brickwork or fragmented stone and might translate badly. Detritus or a similar word with a wider generic use would be better here if needed at all.

I disagree, and find rubble to be a perfectly apt and descriptive term. The primary dictionary definition of the term--appearing above and before the demolition-related usage you've described--is "broken fragments;  a miscellaneous confused mass or group of... broken... things". I think that sums it up pretty well. Besides, the term rubble is far more widely used than detritus according to Google's NGram:


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Re: Home brew AMSR2 extent & area calculation
« Reply #2304 on: July 13, 2016, 01:55:06 PM »
Rubble is a word usually reserved for describing destroyed brickwork or fragmented stone and might translate badly. Detritus or a similar word with a wider generic use would be better here if needed at all.

I disagree, and find rubble to be a perfectly apt and descriptive term. The primary dictionary definition of the term--appearing above and before the demolition-related usage you've described--is "broken fragments;  a miscellaneous confused mass or group of... broken... things". I think that sums it up pretty well. Besides, the term rubble is far more widely used than detritus according to Google's NGram:



The problem I see with rubble is that, although it can be used for the CAB broken ice no matter the size of the floes:
waste or rough fragments of stone, brick, concrete, etc.,
it also gives the perception that this rubble is going to be removed any day now (I mean, during this season) since it is what should happen with demolition rubble.
But that is not gonna happen any time soon unless retreating edge reaches these areas or a black-swan event happens.

Peter Ellis

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Re: Home brew AMSR2 extent & area calculation
« Reply #2305 on: July 13, 2016, 01:58:39 PM »
What you're looking for is "close pack ice" as distinct from "solid ice".

Jim Pettit

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Re: Home brew AMSR2 extent & area calculation
« Reply #2306 on: July 13, 2016, 03:27:17 PM »
The problem I see with rubble is that... it also gives the perception that this rubble is going to be removed any day now (I mean, during this season) since it is what should happen with demolition rubble.
But that is not gonna happen any time soon unless retreating edge reaches these areas or a black-swan event happens.

I'm not sure how imminent removal is implied through use of the term rubble, any more than the words garbage or ruins implies the same. But folks should feel free to use whatever term works for them; I'll continue to use the awesomely descriptive term rubble to refer to such sea ice, and just trust that readers/listeners won't have too much trouble understanding.

Cheers!

Tor Bejnar

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Re: Home brew AMSR2 extent & area calculation
« Reply #2307 on: July 13, 2016, 03:43:35 PM »
"Ice rubble" is a term used in books, according to Google's Ngram Viewer.  My preferred term, "mélange", appears (via a quick internet search of usage) to mean a mixture of icebergs and sea ice or old sea ice and young sea ice, either as a tight pack (perhaps still 'glued' together) or quite broken up and somewhat scattered.
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plinius

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Re: Home brew AMSR2 extent & area calculation
« Reply #2308 on: July 13, 2016, 06:11:32 PM »
...and to my knowledge, detritus is reserved for _organic_ material and already in use to address organic debris on the surface. So one really does not want to use detritus.

Neven

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Re: Home brew AMSR2 extent & area calculation
« Reply #2309 on: July 14, 2016, 12:10:32 AM »
 ;D
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slow wing

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Re: Home brew AMSR2 extent & area calculation
« Reply #2310 on: July 14, 2016, 02:01:20 AM »
 ;D


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Re: Home brew AMSR2 extent & area calculation
« Reply #2311 on: July 14, 2016, 06:51:10 AM »
Hello,

My extend yearly average graphs are now available on the new jaxa web site : https://ads.nipr.ac.jp/vishop/#/extent

You have to select on the right side "annual graph", than "Draw linear fitting line from visible region" and you get exactly my graph. http://forum.arctic-sea-ice.net/index.php/topic,382.msg81847.html#msg81847

Best regards,

Etienne

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Re: Home brew AMSR2 extent & area calculation
« Reply #2312 on: July 14, 2016, 08:18:10 AM »
                    0.2                     0.6                  -430.4
Second in ranking, very close behind 2012.

Update 20160713.

Extent: -130.0 (-616k vs 2015, -240k vs 2014, -295k vs 2013, +77k vs 2012)
Area: -42.7 (-403k vs 2015, -391k vs 2014, -286k vs 2013, +78k vs 2012)
 
You will find the updated graphs in the top post

Regional extent declined most in Chukchi (-42k), Hudson (-35k) and CAB (-26k).

Regional area declined most in ESS (-36k), there was an uptick in CAA (+22k).

Regional delta map is from ESS. Lots of current and potential melting.

Wipneus

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Re: Home brew AMSR2 extent & area calculation
« Reply #2313 on: July 14, 2016, 08:24:48 AM »
Animation of Chukchi and the disappearing ice cover. Some polynyas are developing in the ice pack, it remains to be seen if this is permanent or caused by the cyclone currently over the area.
« Last Edit: July 14, 2016, 09:44:43 AM by Wipneus »

slow wing

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Re: Home brew AMSR2 extent & area calculation
« Reply #2314 on: July 14, 2016, 09:01:51 AM »
Sorry Wipneus, but I'm only getting the first day of that gif, a 95 kB file.

Wipneus

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Re: Home brew AMSR2 extent & area calculation
« Reply #2315 on: July 14, 2016, 09:46:00 AM »
Sorry Wipneus, but I'm only getting the first day of that gif, a 95 kB file.

I had to drop a few frames and trimmed it a bit until the forum software dogested it.

Laurent

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Andreas T

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Re: Home brew AMSR2 extent & area calculation
« Reply #2317 on: July 14, 2016, 03:05:45 PM »
For the people who like to say "poof": here is the last traceable piece of the floe I have been tracking since its disintegration at the end of May. it has been moving about   the ice edge (not a clear edge, I know) in the Beaufort sea ever since in my last collection of images I marked it "II"
... and the one I tracked and wrote about here http://forum.arctic-sea-ice.net/index.php/topic,382.msg79235.html#msg79235 most recently has fragmented into too many pieces to track them all.
It is nevertheless instructive to take the bother to look for them and one has not changed much since the original floe broke up on the 27. of May.
http://forum.arctic-sea-ice.net/index.php/topic,1493.msg78438.html#msg78438
I am showing 721bands this time because it tells more about the nature of the ice of which the floes are composed.

image from http://go.nasa.gov/29Sa3Da

epiphyte

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Re: Home brew AMSR2 extent & area calculation
« Reply #2318 on: July 14, 2016, 05:03:34 PM »
Sorry Wipneus, but I'm only getting the first day of that gif, a 95 kB file.

I had to drop a few frames and trimmed it a bit until the forum software dogested it.

Now that is a word worthy of immortalization:

    Teacher: "Jimmy - where is your homework"
    Jimmy:   "My puppy dogested it"

epiphyte

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Re: Home brew AMSR2 extent & area calculation
« Reply #2319 on: July 14, 2016, 05:16:53 PM »
remember all the "poof" theory, which will be next and BTW the poor ice condition between ESS and the pole that was not shown in AMSR yesterday is clearly there today, just for those who remember the discussion and
still on course to second lowest without and lowest with GAC.

I remember it well ;)   At the time, (Aug 2014) Neven was kind enough to put up the initial posting on his blog.  Which is wonderful - because rather than descending into another interminable diatribe about the dangers of statistical regression on extent/area , I can just repost the link! Viz:

http://neven1.typepad.com/blog/2014/08/poof-its-gone.html

Rob Dekker

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Re: Home brew AMSR2 extent & area calculation
« Reply #2320 on: July 15, 2016, 06:50:16 AM »
For the people who like to say "poof": here is the last traceable piece of the floe I have been tracking since its disintegration at the end of May. it has been moving about   the ice edge (not a clear edge, I know) in the Beaufort sea ever since in my last collection of images I marked it "II"

Thanks Andreas. Let me just note that I find it remarkable how well these MYI flows survive in the Beaufort. Especially when compared to the slush ice (should I say rubble :) ) and FYI in the Gyre, or that flushes out of Amundsen Gulf, which seems to immediately disintegrate as soon as it hits that open Beaufort water.
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Re: Home brew AMSR2 extent & area calculation
« Reply #2321 on: July 15, 2016, 10:28:44 AM »
Still second place (but close) to 2012. We are getting near the time that all years in my limited data set are quite close at least by extent.

Update 20160714.

Extent: -97.4 (-638k vs 2015, -303k vs 2014, -284k vs 2013, +66k vs 2012)
Area: -130.0 (-560k vs 2015, -510k vs 2014, -323k vs 2013, +25k vs 2012)
 
You will find the updated graphs in the top post

Regional extent dropped most in Chukchi again (-33k). Hudson and Beaufort follow (-20k and -18k).

Regional area plummeted in CAB (-75k). Hudson and Greenland Sea follow at a distance (both -25k).

Regional delta map is the Candian Archipelago. The southern branch of the NW passage has gone "ice free" (apply usual caveats ) for a lot longer stretch.

Wipneus

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Re: Home brew AMSR2 extent & area calculation
« Reply #2322 on: July 15, 2016, 10:36:10 AM »
Animation of is of the Baffin region. The remaining ice against the coast of Baffin Island is now disappearing steadily.

Wipneus

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Re: Home brew AMSR2 extent & area calculation
« Reply #2323 on: July 15, 2016, 10:40:31 AM »
And the surface melting situation (from ADS/Jaxa data). I will let the graphs speak for them selves.

BornFromTheVoid

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Re: Home brew AMSR2 extent & area calculation
« Reply #2324 on: July 15, 2016, 11:34:53 AM »
Hi Wipneus. Thanks for all your updates here.

I have have a little request. Could you put together a graph for the percentage of current area that is experiencing surface melt?
My guess is that much of the recent downturn in total surface melt area to due to area/extent losses, rather than a big reduction in the proportion of the ice surface experiencing melting.
I recently joined the twitter thing, where I post more analysis, pics and animations: @Icy_Samuel

Jim Hunt

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Re: Home brew AMSR2 extent & area calculation
« Reply #2325 on: July 15, 2016, 01:19:59 PM »
Could you put together a graph for the percentage of current area that is experiencing surface melt?

Seconded.

Quote
My guess is that much of the recent downturn in total surface melt area [is] due to area/extent losses, rather than a big reduction in the proportion of the ice surface experiencing melting.

Likewise!
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Thawing Thunder

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Re: Home brew AMSR2 extent & area calculation
« Reply #2326 on: July 15, 2016, 01:21:52 PM »
Yes, BFTV, that would be interesting. Visually picking some of the most outstanding data points and estimating their percentage or proportion, it is obvious that 2016 in fact was leading the graph several times in the last weeks.
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Re: Home brew AMSR2 extent & area calculation
« Reply #2327 on: July 15, 2016, 03:26:42 PM »
Yes, BFTV, that would be interesting. Visually picking some of the most outstanding data points and estimating their percentage or proportion, it is obvious that 2016 in fact was leading the graph several times in the last weeks.

Roll a blue die and a red die and sometimes the blue one is higher and sometimes the red one is. This tells you something about dice, but it doesn't tell you anything about red and blue.

This is a low signal/high noise product with significant bias. It reliably tells you there are more melt ponds in summer than winter, but not a lot else. On any given day its quite capable of saying there are 60% melt ponds where there are none, and none where there are 30%.

This paper by Liu et al (2015) that Rob Dekker pointed out in a blog comment uses melt pond "measurements" to cast doubt on the Schroder method (which uses modelled melt pond fraction)
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20160001390

All I reckon it does is illustrate just how unreliable the "measurements" are.

epiphyte

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Re: Home brew AMSR2 extent & area calculation
« Reply #2328 on: July 15, 2016, 06:10:24 PM »
For the people who like to say "poof": here is the last traceable piece of the floe I have been tracking since its disintegration at the end of May. it has been moving about   the ice edge (not a clear edge, I know) in the Beaufort sea ever since in my last collection of images I marked it "II"

Thanks Andreas. Let me just note that I find it remarkable how well these MYI flows survive in the Beaufort. Especially when compared to the slush ice (should I say rubble :) ) and FYI in the Gyre, or that flushes out of Amundsen Gulf, which seems to immediately disintegrate as soon as it hits that open Beaufort water.


Some of those MYI floes were immobile coastal ice for years - a few maybe decades. All of them were in the heart of the CAB just this January If they had stayed there, they would have been a good bet to be pretty much the last MYI in the arctic. Hardly surprising they are reluctant to give up the ghost!
« Last Edit: July 15, 2016, 06:18:04 PM by epiphyte »

Wipneus

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Re: Home brew AMSR2 extent & area calculation
« Reply #2329 on: July 15, 2016, 06:41:49 PM »
Hi Wipneus. Thanks for all your updates here.

I have have a little request. Could you put together a graph for the percentage of current area that is experiencing surface melt?
My guess is that much of the recent downturn in total surface melt area to due to area/extent losses, rather than a big reduction in the proportion of the ice surface experiencing melting.

Good idea, I will do that. Looking at the code, I noticed I don't like the handling of the pole hole. Have to fix that too, just need some time to do it. Sunday most likely.

BornFromTheVoid

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Re: Home brew AMSR2 extent & area calculation
« Reply #2330 on: July 15, 2016, 08:42:02 PM »
Good idea, I will do that. Looking at the code, I noticed I don't like the handling of the pole hole. Have to fix that too, just need some time to do it. Sunday most likely.

Cool. Looking forward to it, cheers.
I recently joined the twitter thing, where I post more analysis, pics and animations: @Icy_Samuel

A-Team

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Re: Home brew AMSR2 extent & area calculation
« Reply #2331 on: July 15, 2016, 08:54:57 PM »
Below are the last 11 days of AMRSR2 3km along the North Atlantic front. The palette has been intensified as per the small square transfer function, with before (bottom bar) and after (top bar) effects on palette. Next the five whitest shades of white (mostly heavy clouds rather than 95-100% concentration areas) were deleted to transparency.

While this does consolidate areas that were clear on at least one day, favoring the most recent, the adjusted imagery also makes it easier to track movement of features in the pack ice as well as poleward retreat of the front over this short interval.

There are several features where the ice can be seen marching south towards the front, such as the distinctive patch below and to the left of the pole and also some floes above the front.

The second copy of the animation has the alpha channel replaced with forum gray. This gives some idea of how much cloud microwave emissions interfere with sea ice concentration on some days at some locations, for example July 14th  below and left of the pole it is very improbable that concentration plunged suddenly relative to just previous days.

While it would be feasible to compare the first animation with 2013-15, the cloud situation could have been very different (as well as the actual sea ice concentrations underneath). It's fair to say however that the 2016 sea ice concentration can be markedly lower than it might appear on a given day.

It would also be straightforward to quantitate the progression of the ice pack's match-up the warm North Atlantic as 'area under the curve', namely the number of very darkest blue (open ocean) pixels. The front is retreating quite noticeably just within the time frame of the animation, with the extreme for the season unclear at this time.
« Last Edit: July 15, 2016, 09:25:31 PM by A-Team »

jdallen

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Re: Home brew AMSR2 extent & area calculation
« Reply #2332 on: July 15, 2016, 09:51:49 PM »
Below are the last 11 days of AMRSR2 3km along the North Atlantic front. <snippage>
Beautiful work as always, A-Team.

The "Atlantic Front" has been fascinating me since January.  I'm wondering what effect the coming weather - with a fairly powerful low in the Beaufort - will have on movement.  If the persistent flow at the surface sets up right, we could see further, possibly significant movement all along the "AF" towards the CAB.

I'm not sure how much heat will actually get transferred; that will depend on mixing and how much warmer surface water gets driven towards the pack, and for how long.  Where as the ice was being driven towards the "killing zone" previously, we might see the "killing zone" delivered to the ice instead.

However one additional concern regardless of heat is wave action.  If surface wind speeds are sufficient, we now have enough fetch to produce significant swells which could drive directly into the pack, attacking it mechanically.  I'm unclear right now what the effect of that will be. I can't imagine it being anything good.
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Re: Home brew AMSR2 extent & area calculation
« Reply #2333 on: July 16, 2016, 12:03:09 AM »
...
Some of those MYI floes were immobile coastal ice for years - a few maybe decades. All of them were in the heart of the CAB just this January If they had stayed there, they would have been a good bet to be pretty much the last MYI in the arctic. Hardly surprising they are reluctant to give up the ghost!
There is not nearly enough immobile coastal ice in the arctic ocean to form those floes. Could you try to point to the place where this ice has spent decades? There are animations of ice movement showing the disappearance of ice much older than 5years, you would not have to try hard to find them.
The thickness of this ice is due to deformation and compaction of ice near the islands of the Canadian Archipelago where it was last year, i.e. it is due to movement not immobility.
The attached photo shows a region where ice is piled up forming an extended area of thick ice once it has undergone  partial melt and refreezing
sorry this should probably be in a different thread but then everybody else posts comments unrelated to AMSR2 extent and area

Wipneus

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Re: Home brew AMSR2 extent & area calculation
« Reply #2334 on: July 16, 2016, 10:26:26 AM »
Strong declines continue, now area is a fraction ahead of 2012.

Update 20160715.

Extent: -83.3 (-643k vs 2015, -327k vs 2014, -242k vs 2013, +50k vs 2012)
Area: -132.8 (-510k vs 2015, -608k vs 2014, -423k vs 2013, -145k vs 2012)
 
You will find the updated graphs in the top post

No regional extent stands out, ESS declines most with -22k.

Regional area declines big in Laptev and ESS (both -46k), CAA nearly as much with -44k. CAB went up with +27k.

Regional delta map is ESS+Laptev

Wipneus

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Re: Home brew AMSR2 extent & area calculation
« Reply #2335 on: July 16, 2016, 10:35:58 AM »
Animation of the Canadian Archipelago. The ice can be seen to be mobile inside the M'Clure Strait, the winds are just not favorable to move much.

Thawing Thunder

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Re: Home brew AMSR2 extent & area calculation
« Reply #2336 on: July 16, 2016, 11:27:58 AM »

This paper by Liu et al (2015) that Rob Dekker pointed out in a blog comment uses melt pond "measurements" to cast doubt on the Schroder method (which uses modelled melt pond fraction)
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20160001390

All I reckon it does is illustrate just how unreliable the "measurements" are.

The link seems not to be correct  :-\
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Re: Home brew AMSR2 extent & area calculation
« Reply #2337 on: July 16, 2016, 03:54:50 PM »
We do not err because truth is difficult to see. It is visible at a glance. We err because this is more comfortable. Alexander Solzhenitsyn

How is it conceivable that all our technological progress - our very civilization - is like the axe in the hand of the pathological criminal? Albert Einstein

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Re: Home brew AMSR2 extent & area calculation
« Reply #2338 on: July 16, 2016, 06:07:49 PM »
Quote
The "Atlantic Front" has been fascinating since January.  effect of coming weather  on movement. could see  significant movement all along the "AF" towards the CAB.  much heat will actually get transferred  will depend on mixing and how much warmer surface water gets driven towards the pack, and for how long. we might see the "killing zone" delivered to the ice instead.  wave action.  enough fetch to produce significant swells which could drive directly into the pack
Excellent observations.

The first animation compares the open space south of the pack in the direction of Svalbard and Franz Josef for July 17th on the four years archived at AMSR2 3km. The little table shows the relative areas for open ocean (southern yellow and all yellow). This year may evolve into extreme encroachment by the North Atlantic but 2013 also saw an advanced front by this date.

The second animation looks at five day intervals at all of 2016. One day intervals would require a 30 MB file for an entire year, already too much for forum software, and 120 MB for the full four years of record at AMSR2 3km, which involves 1283 images currently.

It would be technically feasible to tile 700x175 pixels swaths into a single animation where each frame compares the same date for all four years. That might be worthwhile if the 2016 front ends up in a remarkable position. The September 15th fronts for 2013-15 are shown in the third animation.

The final animation shows the whole Arctic at five day intervals from January to July, with the palette emphasis on middle-valued sea ice concentrations.
« Last Edit: July 16, 2016, 06:40:47 PM by A-Team »

Wipneus

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Re: Home brew AMSR2 extent & area calculation
« Reply #2339 on: July 17, 2016, 08:21:10 AM »
The standings in the 'race" have not changed much:

Update 20160716.

Extent: -53.8 (-542k vs 2015, -318k vs 2014, -202k vs 2013, +29k vs 2012)
Area: -92.4 (-469k vs 2015, -643k vs 2014, -477k vs 2013, -151k vs 2012)
 
The extent decline is a bit depressed by upticks in Chukchi (+35k) and Beaufort (+18k). A cyclone is passing over the area, some temporary disturbance is possible. Extent decline was big in the CAA (-45k) and Laptev (-23k).

Area dropped big way in the CAA (-49k), ESS (-38k) and CAB (-34k) regions. Laptev area increased +36k.

Regional delta map is CAA. Concentration drops around Prince of Wales Island, some below the 15% limit. A MODIS/Aqua image shows that this open water is for real and that all ice around the island has gone mobile. There is not much reason why not all of the remaining fast ice in the CAA will do so soon.

Wipneus

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Re: Home brew AMSR2 extent & area calculation
« Reply #2340 on: July 17, 2016, 08:28:54 AM »
Animation of Beaufort, one of the bigger floats appears to have broken.

oren

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Re: Home brew AMSR2 extent & area calculation
« Reply #2341 on: July 17, 2016, 09:45:25 AM »
A-Team your animations are as usual most insightful.
I wish there was an easy way to resolve the location of the ice front vs. the movement of the ice. The front can be where it is due to ice movement relative to the pole (dispersion/compaction), or due to Atlantic encroachment. This year it seems to me most of the time the ice moves south yet the front moves north. I wonder if that was the case in 2013 too.
Theoretically the way to do that would be to track individual floes near the front and average their movement, feasible on a short animation but next to impossible without automation for long time-frames and multiple years.

Rob Dekker

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Re: Home brew AMSR2 extent & area calculation
« Reply #2342 on: July 17, 2016, 09:59:51 AM »
A-team, thank you ! What a spectacular long-animation of both the Pacific front and the Atlantic front from Jan-June. I find it interesting that the Atlantic front does not even change much between Jan and June, which suggests that ocean currents define how far the ice can go.
On the Pacific side, the Beaufort Gyre is amazing. Almost scary how it eats up ice.

Wipneus, thank you for again a great daily update.
Looking at your Beaufort animation, I cannot suppress the feeling that today's uptick there is temporary, and that the whole area is in imminent danger of a very steep decline. Possibly even until deep into the CAB. All that ice looks very fragile...

And yes, Big Block broke up on July 16 (see the "Melting season" thread) but it is an attest to the quality and resolution of the AMSR2 source that is shows up on your animation as well !
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Re: Home brew AMSR2 extent & area calculation
« Reply #2343 on: July 17, 2016, 12:45:09 PM »
The Atlantic front seems to extend almost to the continental shelf, and in the east it persists because the altantic waters drain off the shelf in the trough west of the central Kara rise. It'd be interesting to know the temp. anomoly of that water, if there is one.

image from http://geology.com/world/arctic-ocean-bathymetry-map.jpg

Wipneus

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Re: Home brew AMSR2 extent & area calculation
« Reply #2344 on: July 17, 2016, 01:11:36 PM »
At request, a graph ratio of melt extent to total sea ice extent.

No attempt has been made to make a calculated guess of the state inside the pole hole. So I just divide the area with light blue pixels by the area of pixels with ice.

There seems to be much to say for this.There is clearly a tendency to peak at the end of July/ begin of August. The continuing melt during the late season in 2012 is so obvious.

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Re: Home brew AMSR2 extent & area calculation
« Reply #2345 on: July 17, 2016, 01:44:32 PM »
That's very nice, Wipneus! This is basically showing the percentage of the ice pack that is displaying surface melting, right?
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Re: Home brew AMSR2 extent & area calculation
« Reply #2346 on: July 17, 2016, 01:57:50 PM »
That's perfect, Wipneus. Thanks for putting it together.

The contrast between the sudden August drop off in 2014 and 2013 and the continued widespread surface melt in 2012 is quite something. Will be interesting to see where we fall on the graph this year.

Also the lack of surface melt in summer 2014 as a whole is notable.
« Last Edit: July 17, 2016, 02:16:31 PM by BornFromTheVoid »
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Wipneus

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Re: Home brew AMSR2 extent & area calculation
« Reply #2347 on: July 17, 2016, 02:04:13 PM »
That's very nice, Wipneus! This is basically showing the percentage of the ice pack that is displaying surface melting, right?

Yes, but ignoring the pole hole about 0.5 Mm2 for the data from the ascending part of the orbit.

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Re: Home brew AMSR2 extent & area calculation
« Reply #2348 on: July 17, 2016, 02:10:04 PM »
Also the lack of surface melt in summer 2013 as a whole is notable.

Did you mean 2014? My reading of the graph is that 2013 was close to this year until late in July, when it fell off significantly for the rest of the melt season.

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Re: Home brew AMSR2 extent & area calculation
« Reply #2349 on: July 17, 2016, 02:10:56 PM »
Congratulations !
Another great learning aid for everyone interested.
Appears that before the end of the month we'll be able to compare this year directly against 2012, that should be interesting.
Terry