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icy voyeur

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Re: Home brew AMSR2 extent & area calculation
« Reply #2700 on: August 25, 2016, 06:11:34 AM »
Read the last 7 hours of comments and just realized I have wasted my time.

kisses

Rob Dekker

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Re: Home brew AMSR2 extent & area calculation
« Reply #2701 on: August 25, 2016, 06:59:18 AM »
Looking forward to Wipneus' post of today's AMSR results.
With all that dispersed ice, despite cloud influence and ponds refreezing, at some point we should see some significant drops coming through.
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Tigertown

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Re: Home brew AMSR2 extent & area calculation
« Reply #2702 on: August 25, 2016, 07:10:35 AM »
You can see melt trails, despite the clouds, all around the peripheries. There has definitely been a lot of melting. Dispersion is keeping up the numbers, though.
"....and the appointed time came for God to bring to ruin those ruining the earth." Revelation 11:18.

Wipneus

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Re: Home brew AMSR2 extent & area calculation
« Reply #2703 on: August 25, 2016, 01:39:55 PM »
Update 20160824.

Extent: -78.4 (-165k vs 2015, -758k vs 2014, -753k vs 2013, +804k vs 2012)
Area: -147.2 (-433k vs 2015, -1076k vs 2014, -1025k vs 2013, +406k vs 2012)
 
You will find the updated graphs in the top post

The extent drop comes from the CAB (-50k) and the ESS/Laptev  (together -28k).

The same regions take care for the area drop: CAB (-107), Laptev (-31k) and ESS (-15k).

The Arctic Basin delta map is attached. From the reds and blues the movement of ice can be seen. From the big ant-clockwise gyre, most is now from the Siberian seas towards the pole. Most of the extent loss is in the eastern "Wrangel arm".

Wipneus

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Re: Home brew AMSR2 extent & area calculation
« Reply #2704 on: August 25, 2016, 02:59:31 PM »
Time for an updated AB animation based on Jaxa's AMSR2 sea ice concentration.

iceman

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Re: Home brew AMSR2 extent & area calculation
« Reply #2705 on: August 25, 2016, 03:28:34 PM »
Time for an updated AB animation based on Jaxa's AMSR2 sea ice concentration.

What a vivid and detailed picture these three graphics provide.
     Isn't the "Wrangel arm" the western edge of the thick ice that was rotated clockwise by the strong Beaufort Gyre early in the melt season?  now moving the other way.

JimboOmega

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Re: Home brew AMSR2 extent & area calculation
« Reply #2706 on: August 25, 2016, 05:55:51 PM »
Time for an updated AB animation based on Jaxa's AMSR2 sea ice concentration.

It's quite an amazing picture. It's interesting how much has changed on the left side of the picture, where what starts as part of the pack with an area of weakness to its right turns into a whispy arm that's left over, while a big intrusion eats its way from the pole towards Europe...

But the line from the Siberian Islands, and across the islands in general to Greenland seems almost entirely constant - a vertical line that looks likely to break only if it gets eaten from the left side!

oren

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Re: Home brew AMSR2 extent & area calculation
« Reply #2707 on: August 25, 2016, 06:40:38 PM »
Time for an updated AB animation based on Jaxa's AMSR2 sea ice concentration.

Thanks as usual for these insightful animations.
Is that the final remains of Big Block in the Beaufort?

Iakub

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Re: Home brew AMSR2 extent & area calculation
« Reply #2708 on: August 25, 2016, 06:54:52 PM »
Time for an updated AB animation based on Jaxa's AMSR2 sea ice concentration.

Thanks as usual for these insightful animations.
Is that the final remains of Big Block in the Beaufort?

Indeed. Tenacious.

FishOutofWater

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Re: Home brew AMSR2 extent & area calculation
« Reply #2709 on: August 25, 2016, 09:02:55 PM »
The Siberian side is about to be hammered by the dipole from Hell. The wind fetch goes from Siberia to the Greenland sea in 48 hours and the pressure gradient is as tight as I have ever seen in the Arctic. The wind and the waves across the Arctic are going to pulverize the sea ice on east Siberian side and compact the ice near Greenland.

I posted the map in the 2016 melt season thread. Earlier predictions of an intense compaction event are about to verify. It's going to be very interesting.

bbr2314

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Re: Home brew AMSR2 extent & area calculation
« Reply #2710 on: August 26, 2016, 03:56:45 AM »
AMSR2 out. Today's map shows clouds again interfering over the "Wrangel Arm" and ice N of Siberia but the losses across the rest of the CAB are horrific. I think they will more than counter and probably indicate another 100K+ drop in the cards once Wipneus posts.

More importantly, it points to another century drop or two (or three) in the coming days as HP slides in and we get better glimpses of what's underneath those clouds.


budmantis

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Re: Home brew AMSR2 extent & area calculation
« Reply #2711 on: August 26, 2016, 06:07:40 AM »
I just posted the same map on the melting season thread, noting that almost 5/8's of the ice above 80 degrees is at 75% or less concentration.

Wipneus

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Re: Home brew AMSR2 extent & area calculation
« Reply #2712 on: August 26, 2016, 05:26:51 PM »
Update 20160825.

Extent: -54.9 (-182k vs 2015, -786k vs 2014, -777k vs 2013, +845k vs 2012)
Area: -10.7 (-426k vs 2015, -1077k vs 2014, -975k vs 2013, +515k vs 2012)
 
You will find the updated graphs in the top post

Regional extent declined most in the ESS (-31k) and Chukchi (-21k).

Regional area was down -31k in the CAB but increased +21k in Laptev.

The attached delta map shows those regions with highest extent changes. The wind-driven compaction is the most eye catching feature.



Wipneus

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Re: Home brew AMSR2 extent & area calculation
« Reply #2713 on: August 26, 2016, 05:34:32 PM »
The animation is on the other side. The arctic low, filling up, is travelling close to the ice pack edge near the Barents. As usual this season we can observe ice melting over a wide Atlantic front.

Needs a click to start.

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Re: Home brew AMSR2 extent & area calculation
« Reply #2714 on: August 26, 2016, 06:25:01 PM »
Wow that's simply amazing

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Re: Home brew AMSR2 extent & area calculation
« Reply #2715 on: August 26, 2016, 06:28:08 PM »
Update 20160825.

Extent: -54.9 (-182k vs 2015, -786k vs 2014, -777k vs 2013, +845k vs 2012)
Area: -10.7 (-426k vs 2015, -1077k vs 2014, -975k vs 2013, +515k vs 2012)
 
You will find the updated graphs in the top post

Regional extent declined most in the ESS (-31k) and Chukchi (-21k).

Regional area was down -31k in the CAB but increased +21k in Laptev.

The attached delta map shows those regions with highest extent changes. The wind-driven compaction is the most eye catching feature.
Yes a lot of red in the southern edge of the arms, but also the edges facing East traveling eastward are in red. Warm waters

Tor Bejnar

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Re: Home brew AMSR2 extent & area calculation
« Reply #2716 on: August 26, 2016, 07:16:24 PM »
The animation is on the other side. The arctic low, filling up, is travelling close to the ice pack edge near the Barents. As usual this season we can observe ice melting over a wide Atlantic front.

Needs a click to start. [Tor's edit: please do so!]

I particularly appreciate/enjoy (something like that!) seeing the wind-driven ice skirting Schmidt Island and piling up along Komsomolets and Pioneer Islands' shores.  (Map of Severnaya Zemlya from Wikipedia.)
Arctic ice is healthy for children and other living things because "we cannot negotiate with the melting point of ice"

FishOutofWater

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Re: Home brew AMSR2 extent & area calculation
« Reply #2717 on: August 26, 2016, 07:29:15 PM »
The continued obliteration of sea ice on the Atlantic front has been stunning at Svalbard for months but now it is happening along the channels where warm water is flowing from the Barents and Kara seas into the Arctic. Strong low pressure over the Arctic ocean pulls warm Atlantic water into the Barents sea and increases flow from the Barents into the Siberian seas.

This has been an amazingly interesting year in the Arctic and the Arctic low just keeps on spinning.

Thawing Thunder

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Re: Home brew AMSR2 extent & area calculation
« Reply #2718 on: August 26, 2016, 10:46:36 PM »
Wipneus, is there a glitch in the compactness graph, or is that drop real??? :o
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Rob Dekker

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Re: Home brew AMSR2 extent & area calculation
« Reply #2719 on: August 27, 2016, 06:32:23 AM »
Wipneus, is there a glitch in the compactness graph, or is that drop real??? :o

It appears to be real. Area is reducing very quickly, while extent reduces slower.
Results in an unprecedented drop in concentration.
This is what Wipneus had to say about it on the "area and extent" thread :

Quote
Yup, and it got worse today. Unusual low and late minimum, possibly record low and/or late (for the NSIDC compactness).

Here is the graph :


In my opinion, 'area' cannot drop much further without 'extent' dropping with it, and thus we either see 'area' recover shortly, or (more likely) 'extent' will start dropping faster as the fine-grained free floating dispersed ice in the Wrangel Arm starts to disappear.

But these are surely interesting times in the Arctic.
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Let's not waste either.

Wipneus

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Re: Home brew AMSR2 extent & area calculation
« Reply #2720 on: August 27, 2016, 03:34:08 PM »
Update 20160826.

Extent: -87.3 (-170k vs 2015, -803k vs 2014, -854k vs 2013, +850k vs 2012)
Area: -1.7 (-388k vs 2015, -964k vs 2014, -956k vs 2013, +607k vs 2012)
 
You will find the updated graphs in the top post

For regional extent changes look at the CAB (-60k) and ESS -26k).

Area in the CAB increased (+28k) and CAA (+16k), it declined in the ESS (-24k). Some small changes elsewhere.

No surprises in the attached Arctic Basin delta map. Activity in the ususal laces.

 

Wipneus

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Re: Home brew AMSR2 extent & area calculation
« Reply #2721 on: August 27, 2016, 03:39:08 PM »
And an animation with the almost empty Beaufort and the thinning Wrangel arm.

Nick_Naylor

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Re: Home brew AMSR2 extent & area calculation
« Reply #2722 on: August 27, 2016, 11:26:09 PM »
Here's a broader view of the last 10 days:
https://ads.nipr.ac.jp/vishop/#/gallery

Wipneus

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Re: Home brew AMSR2 extent & area calculation
« Reply #2723 on: August 28, 2016, 09:51:44 AM »
With a century extent drop 2016 keeps its little "advantage"  of 2015 (that went -160k down on the same date).

Update 20160827.

Extent: -102.1 (-110k vs 2015, -904k vs 2014, -920k vs 2013, +753k vs 2012)
Area: -28.7 (-378k vs 2015, -966k vs 2014, -941k vs 2013, +542k vs 2012)
 
You will find the updated graphs in the top post

Regional extent declines in the CAB (-85k) and Chukchi (-27k).

Regional area declined in ESS (-27k) and Chukchi (-19). It increased over the CAB (+16k).

Most of these changes are in the "arm", the Beaufort side is practically gone. The attached delta map shows it in detail.

Wipneus

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Re: Home brew AMSR2 extent & area calculation
« Reply #2724 on: August 29, 2016, 02:28:49 PM »
Extent drops relatively slowly (compared with record years), only -86k below 2015.

Update 20160828.

Extent: -46.0 (-86k vs 2015, -921k vs 2014, -922k vs 2013, +750k vs 2012)
Area: -165.1 (-461k vs 2015, -1113k vs 2014, -1069k vs 2013, +429k vs 2012)
 
You will find the updated graphs in the top post

Regional extent dropped in the CAB (-27k) and CAA (-22k).

Regional area was dominated by the losses in the CAB (-145k), second (way behind) was CAA (-17k).

Some recovery (un-poofing) of ice in the Beaufort side of the Wrangel arm is the main reason that extent did not drop faster. It is not unreasonable to expect this ice to disappear again later.
In the mean time on the other side concentration is dropping and polynyas (re)appearing, see attached delta map.

Wipneus

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Re: Home brew AMSR2 extent & area calculation
« Reply #2725 on: August 29, 2016, 02:48:10 PM »
A side by side animation of the Arctic Basin comparing 2016 and 2012. Lots of opportunity for melting and compaction, but there is little time left for melting an only a bit more for compaction.

Must click to start animation.

crandles

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Re: Home brew AMSR2 extent & area calculation
« Reply #2726 on: August 29, 2016, 05:38:27 PM »
Should we expect an early area minimum because of large areas of medium concentration at high latitudes which will fill in? As these are fully counted for extent throughout perhaps we should also anticipate a long gap between area minimum and extent minimum this year?

Maybe these are just too weather dependant for such predictions to be reliable?

Shared Humanity

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Re: Home brew AMSR2 extent & area calculation
« Reply #2727 on: August 29, 2016, 10:30:31 PM »
You can see the effects of those west to east winds along the CAA. Ice really accelerates into the Fram.

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Re: Home brew AMSR2 extent & area calculation
« Reply #2728 on: August 29, 2016, 11:35:21 PM »
A side by side animation of the Arctic Basin comparing 2016 and 2012. Lots of opportunity for melting and compaction, but there is little time left for melting an only a bit more for compaction.

Despite the lower extent and area in 2012, it seems to me the ice pack is in a much more fragmented, 'unhealthy' state now than it was on this date four years ago. Maybe by April 2017 we'll see a strong collage of 2nd or 3rd year ice floes cemented by 2 to 3 m of first year ice, but I don't think that's the way it works. Others who've been observing sea ice for longer than I have, please feel free to enlighten me.

bbr2314

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Re: Home brew AMSR2 extent & area calculation
« Reply #2729 on: August 30, 2016, 04:00:29 AM »
To my eyes, AMSR2 today shows a massive retreat of the compaction boundary marking the Triangle of Fortitude. Probably 10-15KM across 1000KM+ = 120K+ loss easily of core structural area. Everything outside of these bounds is now subject to flash melting and is quickly eroding from the bottom.

FRAM export is accelerating, and the entire Atlantic front is also collapsing outside of what's being extruded NW of Svalbard.



Should also be noted that it seems like instead of completely solidifying, the open CAA is allowing the pile-up of thicker ice along its bounds to leak through, at least that's what DMI would indicate coming down the pipe (same for Nares). Could this result in a relative thickening of the CAA for next year while the Arctic loses what little remnants survive the summer?



Comparing with 2012.... I would say we have about 3/5 the same "stable" area that survived into the end of September and that means we still have over a million square kilometers left to lose.

« Last Edit: August 30, 2016, 04:15:11 AM by bbr2314 »

Wipneus

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Re: Home brew AMSR2 extent & area calculation
« Reply #2730 on: August 30, 2016, 04:15:58 PM »
Slow extent decline makes 2016 and 2015 almost equal. The area lead is comfortable.

Update 20160829.

Extent: -5.8 (-35k vs 2015, -884k vs 2014, -884k vs 2013, +757k vs 2012)
Area: -32.8 (-410k vs 2015, -1135k vs 2014, -1190k vs 2013, +438k vs 2012)
 
You will find the updated graphs in the top post

Regional extent declines are in the CAB (-30k) and Laptev (-21k). Extent increases in CAA (+24k) and Chukchi (+12k).

Regional area dropped in the CAB (-73k), but increased in the CAA (+25k).

Attaches is the delta map of the region of the Barents Bite. There is quite some internal extent loss there: polynyas growing in number and sizes.


« Last Edit: August 30, 2016, 04:46:05 PM by Wipneus »

Wipneus

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Re: Home brew AMSR2 extent & area calculation
« Reply #2731 on: August 30, 2016, 05:42:28 PM »
And an animation of the ESS with its bite (which started growing from the New Siberian Islands, but shifted with the winds).

psymmo7

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Re: Home brew AMSR2 extent & area calculation
« Reply #2732 on: August 30, 2016, 11:53:50 PM »
Has anyone noticed how warm the average temperature is getting north of the 80th parallel? Figure courtesy of Danish Meteorological service. http://ocean.dmi.dk/arctic/meant80n.uk.php. The green line is the multi year average. Their records go back to 1958 and such a deviation for this time of year is rather unusual.
« Last Edit: August 30, 2016, 11:59:31 PM by psymmo7 »

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Re: Home brew AMSR2 extent & area calculation
« Reply #2733 on: August 31, 2016, 12:18:55 AM »
Great to have UH AMSR2 3.1k for the 2012 end game. The data currently extends from August 1st to the end of September and is animated below. (Wipneus already provided a 2012-2016 side-by-side for 18-28 August in #2725; I posted animations for 2013-2015 from August to Sept 25th earlier.) It is very convenient to get the data -- Antarctica too -- by anonymous ftp at ftp://ftp-projects.zmaw.de/seaice/AMSR2/3.125km/

It appears that 25 Sep 12 is a suitable cut-off date as the CAA ice body begins to grow after that (note a new type of glitch on Sep 28th). Ice extends much further south in the Fram than in 2016 but the Barents melt line is farther north than shelf bathymetry.

Some residual ice persisted around Wrangel in 2012 but nothing resembling an arm was present on August 1st. This year also does not provide evident parallels to the Laptev bite, block of late ice  off western Siberia, low concentration block near the pole in the European sector nor NW Passage situation of 2016. The later days are instead a fringe melt and compactification story.
« Last Edit: August 31, 2016, 12:29:26 AM by A-Team »

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Re: Home brew AMSR2 extent & area calculation
« Reply #2734 on: August 31, 2016, 12:57:38 AM »
Has anyone noticed how warm the average temperature is getting north of the 80th parallel?

I did. I was hoping someone said something about it.

To A-Team: Thank you very much for your animations. If pictures are worth a thousand words, are animations worth tens of thousands? I think so. Thanks again.
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Lord M Vader

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Re: Home brew AMSR2 extent & area calculation
« Reply #2735 on: August 31, 2016, 07:01:40 AM »
Archmid & Psymmo: I wrote about the spectacular DMI graph but in the 2016 melting season thread. See post #4413. The only other year comparable to this year is 1984 when you check earlier year from DMI.

//LMV

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Re: Home brew AMSR2 extent & area calculation
« Reply #2736 on: August 31, 2016, 01:42:43 PM »
There's also a blog called Arctic Sea Ice Blog where it was mentioned yesterday, I believe.  ;)
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Re: Home brew AMSR2 extent & area calculation
« Reply #2737 on: August 31, 2016, 05:15:07 PM »
I notice Climate Reanalyzer is predicting a lot of anomalous warmth on  the Siberian Quadrant over the next week. When you combine that with the state of the Ice and the direction of the wind it looks like we could have a way to go yet. About 18 days to minimum provides a lot of time for reduction in area and extent particularly when ESS and Laptev have still got 250K above 2012 between them. 
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Re: Home brew AMSR2 extent & area calculation
« Reply #2738 on: August 31, 2016, 06:24:43 PM »
A century extent drop increases the distance to 2015 so much that the second place for the seasons minimum is assured (in my limited set of years of course).

Update 20160830.

Extent: -118.7 (-146k vs 2015, -960k vs 2014, -975k vs 2013, +614k vs 2012)
Area: -75.5 (-469k vs 2015, -1133k vs 2014, -1309k vs 2013, +319k vs 2012)
 
You will find the updated graphs in the top post

Regional extent dropped in the CAB -90k and the Laptev -21k.

For regional area the declines are CAB: -54k and ESS: -19k.

Attached the delta map of the Arctic Basin (at 6.25km res). The deterioration of the Wrangel arm continues while the Laptev arm can be seen moving (again) to the east (left in the image).
 

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Re: Home brew AMSR2 extent & area calculation
« Reply #2739 on: August 31, 2016, 06:29:37 PM »
Animation of the Greenland Sea, there is definitely movement through the Fram and beyond.

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Re: Home brew AMSR2 extent & area calculation
« Reply #2740 on: August 31, 2016, 07:00:18 PM »
It is been a while that I posted the melting extent graphs (data from ADS/Jaxa thickness melting map). The late high melting extent ratio, exceeding 2012 is remarkable.

(in short melting extent ratio is the fraction of grid cells with ice where the ADS/Jaxa algorithm has detected melting.)

A click will get you a bigger picture.

JimboOmega

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Re: Home brew AMSR2 extent & area calculation
« Reply #2741 on: August 31, 2016, 09:12:32 PM »
It is been a while that I posted the melting extent graphs (data from ADS/Jaxa thickness melting map). The late high melting extent ratio, exceeding 2012 is remarkable.

(in short melting extent ratio is the fraction of grid cells with ice where the ADS/Jaxa algorithm has detected melting.)

A click will get you a bigger picture.

Just to be clear - this is "top" melting, not the "bottom" melting from warm water that is often mentioned?

Richard Rathbone

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Re: Home brew AMSR2 extent & area calculation
« Reply #2742 on: September 01, 2016, 02:01:26 AM »
It is been a while that I posted the melting extent graphs (data from ADS/Jaxa thickness melting map). The late high melting extent ratio, exceeding 2012 is remarkable.

(in short melting extent ratio is the fraction of grid cells with ice where the ADS/Jaxa algorithm has detected melting.)

A click will get you a bigger picture.

Just to be clear - this is "top" melting, not the "bottom" melting from warm water that is often mentioned?

Melt ponds are what its calibrated against. I don't believe there's 20% melt pond extent in the freezing season, which is what it claims and I think there are at least two sources of this bias. One due to the high noise level, and one due to open water in the proximity of ice looking like melt ponds on the ice as far as the sensor is concerned. So I'm not that surprised its higher than 2012 at this time, because 2012 was rather more compact with rather less opportunity for water next to ice to be confused with water on ice.

I should add that its also exceptionally warm, so there is also reason to believe some of that excess is a genuine signal of extra melt pond coverage with more area above zero now than in other years.
« Last Edit: September 01, 2016, 02:10:59 AM by Richard Rathbone »

Artful Dodger

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Re: Home brew AMSR2 extent & area calculation
« Reply #2743 on: September 01, 2016, 04:31:40 AM »
Melt ponds are what its calibrated against.

Hi Richard,

AMSR-2 data has not been calibrated yet. For now, ASI products from JAXA, Uni-Bremen, Uni-Hamburg et.al just reuse the P0 and P1 coefficients calculated for the AMSR-E 89 GHz channel.

I'm sure they'll get around to it, but budgets, yada yada... Recalibration may have to be completed after the service life of GCOM-W1, the bird AMSR-2 flies on.

So it'll do for now, while at least providing data consistency if not the utmost possible accuracy.  8)

Cheers,
Lodger
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Rob Dekker

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Re: Home brew AMSR2 extent & area calculation
« Reply #2744 on: September 01, 2016, 07:49:31 AM »
Just to be clear - this is "top" melting, not the "bottom" melting from warm water that is often mentioned?

As far as I know, neither AMSR nor SSMIS can distinguish between (water in) melting ponds and open water between ice.
So I have to assume that the melting "extent" shown in Wipneus graph from ADS/JAXA includes water between ice (as in leads and polynia).

Therefor, the "melt extent" reported has more to do with low ice concentration than with actual "top melt".
« Last Edit: September 01, 2016, 08:01:17 AM by Rob Dekker »
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Re: Home brew AMSR2 extent & area calculation
« Reply #2745 on: September 01, 2016, 07:57:17 AM »
Regarding "top-melt" or "bottom-melt" observations, look at this latest Obuoy14 image :



How much of this surface would be considered "melting" as observed by satellite ?
I suggest that AMSR has no way to distinguish that wet "rubble" ice from "melting" area, even though it ended up there because of bottom melt.
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Re: Home brew AMSR2 extent & area calculation
« Reply #2746 on: September 01, 2016, 01:24:59 PM »
Quote
Animation of the Greenland Sea, there is definitely movement through the Fram and beyond.

And one thing to note on this year compared to 2012.....is that in 2012, there was a LOT MORE ice that "wrapped around" the northeast corner of Greenland, and the ice came much further SOUTH in 2012 on Greenland's northeast coast.

This year.....much more ice has cleared out on the northeast coast, and likely makes it easier for ice to flow OUT of the Fram.

I suspect that in the coming few years this will increase even more.....as the "landbound" ice along the northeast coast is melted further and further north.........earlier and earlier in the year.

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Re: Home brew AMSR2 extent & area calculation
« Reply #2747 on: September 01, 2016, 01:29:42 PM »
I suspect the melting ratio shown above is simply the percentage of cells that show a decline in coverage from day to day.  So if the calculated coverage goes from 61% of the cell to 60% that  would be considered melting and if it does the reverse that would not be melting.
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Richard Rathbone

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Re: Home brew AMSR2 extent & area calculation
« Reply #2748 on: September 01, 2016, 02:33:16 PM »
Melt ponds are what its calibrated against.

Hi Richard,

AMSR-2 data has not been calibrated yet. For now, ASI products from JAXA, Uni-Bremen, Uni-Hamburg et.al just reuse the P0 and P1 coefficients calculated for the AMSR-E 89 GHz channel.

I'm sure they'll get around to it, but budgets, yada yada... Recalibration may have to be completed after the service life of GCOM-W1, the bird AMSR-2 flies on.

So it'll do for now, while at least providing data consistency if not the utmost possible accuracy.  8)

Cheers,
Lodger

The reference from Wipneus is buried somewhere up the thread, but this is a different product and its calibrated against visual observation of melt ponds. Its also a very noisy calibration, even by  microwave standards.

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Re: Home brew AMSR2 extent & area calculation
« Reply #2749 on: September 01, 2016, 04:18:15 PM »
Regarding "top-melt" or "bottom-melt" observations, look at this latest Obuoy14 image :



How much of this surface would be considered "melting" as observed by satellite ?
I suggest that AMSR has no way to distinguish that wet "rubble" ice from "melting" area, even though it ended up there because of bottom melt.

There must be some top-melt as the icicles have melted!