Arctic Sea Ice : Forum

Cryosphere => Arctic sea ice => Topic started by: Wipneus on June 17, 2013, 05:00:34 PM

Title: Home brew AMSR2 extent & area calculation
Post by: Wipneus on June 17, 2013, 05:00:34 PM
The nice guys at the University of Hamburg have provided the results of their unfinished sea ice concentration calculation based on L1(R) AMSR2 data from JAXA  online in some very handy NetCDF files.

Quote
Citation of source data:
Data:
Beitsch, A., L. Kaleschke and S. Kern (2013), "AMSR2 ASI 3.125 km Sea Ice Concentration Data, V0.1", Institute of Oceanography, University of Hamburg, Germany, digital media
(ftp-projects.zmaw.de/seaice/), [BEGIN Jan 2013- present];
Articles:
Spreen, G., L. Kaleschke, G. Heygster (2008), "Sea Ice Remote Sensing Using AMSR-E 89
GHz Channels", J. Geophys. Res., 113, C02S03, doi:10.1029/2005JC003384.

Kaleschke, L., C. Lüpkes, T. Vihma, J. Haarpaintner, A. Bochert, J. Hartmann, G. Heygster,
"SSM/I Sea Ice Remote Sensing for Mesoscale Ocean-Atmosphere Interaction Analysis",
Can. J. Rem. Sens., 27(5), 526-537, 2001.
see also:
http://neven1.typepad.com/blog/2013/06/new-map-on-the-block.html (http://neven1.typepad.com/blog/2013/06/new-map-on-the-block.html)
data:
ftp://ftp-projects.zmaw.de/seaice/AMSR2/ (ftp://ftp-projects.zmaw.de/seaice/AMSR2/)
[EDIT 2017-03-30: source adress change]
ftp://ftp-projects.cen.uni-hamburg.de/seaice/AMSR2/ (ftp://ftp-projects.cen.uni-hamburg.de/seaice/AMSR2/)

The data is provided at a 3.125x3.125 km grid.

Summing the area of the grid cells that have an ice concentration of 15% (or some other value) should give a measure of the extent that can be compared with the well known Jaxa/Ice, NSIDC and others that do similar calculations.

Here I present the first results.

The calculations have the following features:

1) uses the actual area of the grid cells, which may deviate a few perecent from the nominal 3.125^2 km2;
2) Ice concentration of the "North Pole hole" is calculated to be the same as a small ring (width 25% of the radius of the hole itself) around the hole;
3) Spurious ice is removed from coastlines where there is open water within a "few" grid cells;
3a) pixels labeled as sea, separated from the world oceans are considered "lake" and discarded;
4) "phantom" ice fleets that appear and disappear randomly, especially at lower latitudes are detected and removed;
5) an ice mask is used to split the area into regions as closely as possible similar to those of the Cryosphere Today.

 
Of course it may be regarded as a foolish undertaking:

1) the 3.125 km grid cannot be compared with anything else available;
2) the 3.125 km ice concentration values are influenced by clouds and water vapor (as a consequence of using the hi-res 89 GHz microwave band);
3) The ice concentration data is unofficial and work-in-progress;
4) The data is only available for 2013, we cannot compare with any other year directly.

Well, it is fun to try and I was supprised when I saw the first result:

(https://sites.google.com/site/arctischepinguin/home/amsr2/grf/amsr2-extent-all-cmpare.png)
 
My calculations have been tracking Jaxa's quite close.
I expected a lot of noise as there is no filter (Jaxa filters 2 days), the unfiltered data looks quite usable.
Since end of May, the two have been diverging. This is to be expected, when hole fall in the ice cover the smaller grid will more likely pick them up than the wider grid.

Considering now:
1) extent per region;
2) area calculation;
3) compactness calculation (like CAPIE but from the same source)

[update put the area graph in the top post:]
(https://sites.google.com/site/arctischepinguin/home/amsr2/grf/amsr2-area-all-cmpare.png)

[update put the compactness graph in the top post]
(https://sites.google.com/site/arctischepinguin/home/amsr2/grf/amsr2-compact-compare.png)

[update: add regional graphs]

(https://sites.google.com/site/arctischepinguin/home/amsr2/grf/amsr2-extent-regional.png)

(https://sites.google.com/site/arctischepinguin/home/amsr2/grf/amsr2-area-regional.png)

(https://sites.google.com/site/arctischepinguin/home/amsr2/grf/amsr2-compact-regional.png)
Title: Re: Home brew AMSR2 extent calculation
Post by: ChrisReynolds on June 17, 2013, 05:31:21 PM
Good stuff Wipneus,

One small point, you lost me here
Quote
Since end of May, the two have been diverging. This is to be expected, when hole fall in the ice cover the smaller grid will more likely pick them up than the wider grid.
Title: Re: Home brew AMSR2 extent calculation
Post by: crandles on June 17, 2013, 05:59:09 PM
Excellent.   :)  8)

Chris, I would expect a fine grid to measure more area of holes because 15% of a large grid is more than 15% of a small grid. So if a cell has a single hole and that hole is between 15% of small and 15% of large cell size then it will be counted as a hole on the small grid but counted as fully ice covered if you use the large grid.
Title: Re: Home brew AMSR2 extent calculation
Post by: anonymous on June 17, 2013, 06:08:50 PM
If I look at the area along the Siberian coast it seems the algo picks up melting ponds as open water. The difference between MODIS (http://www.arctic.io/zoom/5pHG5/0.7467385;0.1739361;2.3213308) and AMSR2 (http://www.arctic.io/zoom/iiAqy/0.4914965;0.5532558;2.3824985) is quite substantial. On the other hand this tells me same area no longer qualifies as ice pack, ice swamp is a better designation.
Title: Re: Home brew AMSR2 extent calculation
Post by: SATire on June 17, 2013, 06:40:57 PM
Thank you Wipneus, that you make this possible - you can check Extent and SIA with better resolution and faster than anybody else and you can perform a lot of new statistics, trends and what you want.

I hope this place is appropriate for this, otherwise feel free to move it (e.g. in Wipneus' future home-brew-SIA thread?).
For us noobs, who can not programm such nice tools I would like to summarize here an easy way to measure SIA on your own by using a paint programm of your choice. I explain it for gimp, which you can get for free (http://www.gimp.org/ (http://www.gimp.org/)):

To compute SIA from that concentration maps from Wipneus (https://sites.google.com/site/apamsr2/home/pngcby32/ (https://sites.google.com/site/apamsr2/home/pngcby32/)) is totally easy with gimp:

1. Select the area of interest
2. use the histogramm function (Menue: Colors -> information -> histogramm)
3. look up the "mean" value and devide it by 255 (=100% ice) to get the ice fraction
4. multiply by selected area (e.g. number of pixel from histogramm function times 3.125 km times 3.125 again (pixel area)   

If you have the black hole in your selection, choose lower level of histogramm >38 to avoid a wrong mean since the black hole has pixel value of 37.

If you have land in your selection - use a mask or change it's color to black. If there are lakes or artifacts in the area: just paint that black, too  ;)

All warnings Wipneus mentioned above are valid here of course, too.

This is not as flexible and cool as the thing Wipneus is doing, but it is a nice and easy thing to compare SIA in areas of your personal interest from day to day. Just note the position and the size of your selection for comparisons over time and as reference for other poeple interested.

(copy from a comment at http://neven1.typepad.com/blog/2013/06/new-map-on-the-block.html (http://neven1.typepad.com/blog/2013/06/new-map-on-the-block.html))

In attached picture I put in the SIA concentration in % and the selected area for example.

Since Wipneus also gave a map of the CT-region at ASIB - you may compute the CT-SIA with larger resulution on your own in future. One should learn to paint somehow selectively over that "weather smear" features (see redish area in attached picture), which allways disturb also U-Bremens maps for the same reason.
Title: Re: Home brew AMSR2 extent calculation
Post by: ChrisReynolds on June 17, 2013, 07:34:39 PM
Thanks Crandles, obvious really.
Title: Re: Home brew AMSR2 extent calculation
Post by: Wipneus on June 17, 2013, 07:49:52 PM
Good stuff Wipneus,

One small point, you lost me here
Quote
Since end of May, the two have been diverging. This is to be expected, when hole fall in the ice cover the smaller grid will more likely pick them up than the wider grid.

I see on the hi-res pngs lots of isolated grid cell's with less than 15% concentration, more and more within the CAB. These will lower the 3.125 extent, but not Jaxa's. Remember 16 of the 3.125 grid cells fit in one of Jaxa, 3 of them 100% concentration and Jaxa will include all of them to the extent.


Title: Re: Home brew AMSR2 extent calculation
Post by: Neven on June 17, 2013, 08:15:42 PM
Awesome!
Title: Re: Home brew AMSR2 extent calculation
Post by: Wipneus on June 18, 2013, 08:33:32 AM
Extent down 79k7 to 10.403255

Continuing extent losses in the Arctic Basin (asp. between the pole and Barentsz)
Title: Re: Home brew AMSR2 extent calculation
Post by: Wipneus on June 18, 2013, 09:37:25 AM
Region break down (in 1000 km2):

Code: [Select]
           Arctic Basin       East Siberian Sea              Laptev Sea
                   -2.2                    11.8                     0.2
               Kara Sea             Barents Sea           Greenland Sea
                  -27.9                     1.1                     0.0
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                  -34.0                     0.0                   -17.0
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                    2.0                     1.8                   -13.5
             Bering Sea          Sea of Okhotsk                   Total
                   -1.6                    -0.3                   -79.7

Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on June 18, 2013, 10:07:37 AM
Here is the same for area

Code: [Select]
AREAAREAAREAAREAAREAAREAAREAAREAAREAAREAAREAAREAAREAAREAAREA
           Arctic Basin       East Siberian Sea              Laptev Sea
                  -15.7                     5.5                    15.4
               Kara Sea             Barents Sea           Greenland Sea
                  -39.8                     0.1                    -5.0
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                  -34.3                     0.0                   -22.6
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   -0.6                   -18.4                    -5.4
             Bering Sea          Sea of Okhotsk                   Total
                   -1.3                    -0.1                  -122.5
Title: Re: Home brew AMSR2 extent & area calculation
Post by: SATire on June 18, 2013, 11:16:20 AM
Cool Wipneus - you made it! Now all values out there are also at your fingers :D
And thank you very much for sharing that!

Do you think it could be possible to detect the artifacts in the AMSR2-maps one day? As Lars did explain in ASIB there are two features: Melt ponds and water vapour effects - both should be treated differently of course. I have the feeling that both effects are visible in the maps - so there should be some way to detect them automatically, too. But that is not an easy thing.

The weather "smear" features (red stuff in above picture) show less contrast, give a SIA between 60% and 90% and move from day to day by large distances - but there may be overlapp from one day to the next day of course. Maybe a low contrast in a quite big connected area with SIA of 60-80% could be a first warning signal.
A work-around could be to check clusters of 100-200 pixels if SIA reductions with quite low contrast occure suddenly and disappear some days later and after some days to ignore SIA/Extent-losses in such areas. Maybe IJIS is doing something like that?
A perfect way would be to include information from other sensors to detect that - I think it is related to the thick orange clouds visible in MODIS 3-6-7. But unfortunately that pictures are taken at different time and the clouds move fast. Also on channel in JAXA is used to detect that. So maybe a human eye is necessary as reference...

The melt-ponds are visible by a quite rapid reduction of SIA to dark shades of grey, which then stay quite a long time without dropping close to zero. Those things do not move or only very slowly like the pack. If I understood Chris Reynolds right, that is some kind of "cliff-detector" and we could take the values seriously due to albedo things. However - it would be nice to know the amount of SIA reduction related to those melt-ponds.

Do you think those things make sense at all?
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on June 18, 2013, 12:33:08 PM
SATire,

We are not the first people that have been thinking about this stuff. If it where easy, the Uni Hamburg team would have fixed it already. Having an advantage with all microwave bands and polarizations available.

I will think about it myself, perhaps the ideas you give can be automated somehow.

On the other hand, how bad is it? Melt ponds tend to form on First Year Ice, so they will mostly be gone at minimum anyway. The clouds/vapor issue does not seem to cause strange swings compared to the Jaxa/IJS curve.


Title: Re: Home brew AMSR2 extent & area calculation
Post by: SATire on June 18, 2013, 01:34:30 PM
Wipneus,

I think you are right with all your arguments. Probably any algorithm which could solve the vapour-issue would incorporate new software specific artifacts, which could make any results questionable. It would be better for amateurs like us to work with plain data and to discuss any artifacts separatly after viewing the map. Further I believe that you allready have a lot of more fruitfull ideas, since you also have all the PIOMAS data in grids in your hands, too. To repeat it: Great work you did!
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on June 18, 2013, 01:43:55 PM
Area compared with CT area:

(https://sites.google.com/site/arctischepinguin/home/amsr2/grf/amsr2-area-all-cmpare.png)

I am not sure why the divergence goes now the other way. The double cliff is even more pronounced.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: dree12 on June 18, 2013, 02:12:37 PM
Area compared with CT area:

(https://sites.google.com/site/arctischepinguin/home/amsr2/grf/amsr2-area-all-cmpare.png)

I am not sure why the divergence goes now the other way. The double cliff is even more pronounced.

With more holes in the ice, this is to be expected. CT area will consider anything below 15% as 0, whereas AMSR2 would find isolated pieces of concentration.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on June 19, 2013, 08:53:20 AM
Extent down: -39k9 mostly Baffin, also CAA, Beaufort and Chucki
Area up :83k4 almost all CAB

Details (upper is extent, lower half area):

Code: [Select]
           Arctic Basin       East Siberian Sea              Laptev Sea
                   -1.9                     8.8                     6.4
               Kara Sea             Barents Sea           Greenland Sea
                    1.0                     0.7                     0.1
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                  -20.5                     0.0                    -8.4
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   -4.1                    -4.9                   -13.4
             Bering Sea          Sea of Okhotsk            Total Extent
                   -2.0                    -1.7                   -39.9

           Arctic Basin       East Siberian Sea              Laptev Sea
                   88.4                    14.3                     7.0
               Kara Sea             Barents Sea           Greenland Sea
                    4.0                     3.3                     3.4
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                  -20.5                     0.1                    -6.5
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   12.4                    11.2                   -29.5
             Bering Sea          Sea of Okhotsk              Total Area
                   -1.7                    -2.5                    83.4
Title: Re: Home brew AMSR2 extent & area calculation
Post by: SATire on June 19, 2013, 09:28:34 AM
Area up :83k4 almost all CAB
BTW - how do you treat the "value=37-NP-hole"? Do you ignore it or do you give that area some mean SIA from the surrounding like CT?
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on June 19, 2013, 09:40:35 AM
Area up :83k4 almost all CAB
BTW - how do you treat the "value=37-NP-hole"? Do you ignore it or do you give that area some mean SIA from the surrounding like CT?

It is in the top post. I take the average concentration of a small ring (width 25% of the hole radius) and assume that for the hole.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Richard Rathbone on June 19, 2013, 12:22:20 PM
Is there actually refreeze, or is it something like the same ice being counted twice as it moves from one pixel to another between satellite passes?
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on June 19, 2013, 02:29:03 PM
Wouldn't "pixels" with open sea in that case get counted multiple times as well?

Anyway there is an update of 20130618 tomorrow. Mostly those updates don't change anything but perhaps now is different.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Peter Ellis on June 19, 2013, 03:08:57 PM
Is there actually refreeze, or is it something like the same ice being counted twice as it moves from one pixel to another between satellite passes?
Most likely melt ponds showing up (or not) depending on multiple factors like the angle of the satellite relative to the Sun, the amount of water vapour in the atmosphere, cloudiness, temperature, etc.  That's why it affects area much more than extent.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on June 20, 2013, 08:25:53 AM
Update for 20130618 did not change anything.

Extent: down -68k4, fastest runner is Laptev also Baffin, Hudson, Chucki and Greenland sea.

Area: down -40.1 Very mixed on regional scale. Note that Greenland Area increases where extent declined.

Details (upper extent, lower area):

Code: [Select]
          Arctic Basin       East Siberian Sea              Laptev Sea
                   -0.1                     5.7                   -31.1
               Kara Sea             Barents Sea           Greenland Sea
                   12.1                    -4.8                   -10.1
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                  -16.5                    -0.2                    -8.1
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   -0.7                    -0.4                   -10.7
             Bering Sea          Sea of Okhotsk            Total Extent
                   -2.8                    -0.8                   -68.4


           Arctic Basin       East Siberian Sea              Laptev Sea
                   12.1                    14.7                   -42.6
               Kara Sea             Barents Sea           Greenland Sea
                   34.9                    -3.6                     6.8
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                  -26.6                    -0.1                   -28.9
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   24.9                   -20.5                    -7.3
             Bering Sea          Sea of Okhotsk              Total Area
                   -2.6                    -1.3                   -40.1
 
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on June 20, 2013, 11:26:57 AM
Compactness (Area/extent) compared with CAPIE:

(https://sites.google.com/site/arctischepinguin/home/amsr2/grf/amsr2-compact-compare.png)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on June 21, 2013, 08:23:47 AM
Update:

Extent: -44k5. Mostly Baffin, Kara and Greenland Sea. An increase for ESS and Hudson.

Area: -75k3. Mostly same movements as extent, but increase for CAB and noticable decrease for CAA and Beaufort.

The details:
Code: [Select]
Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                    0.5                     9.6                    -0.4
               Kara Sea             Barents Sea           Greenland Sea
                  -13.8                    -6.8                   -14.0
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                  -18.8                    -0.3                     5.9
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   -4.0                    -1.0                    -2.5
             Bering Sea          Sea of Okhotsk            Total Extent
                   -0.1                     1.0                   -44.5

Area:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   38.4                    21.2                    14.2
               Kara Sea             Barents Sea           Greenland Sea
                  -22.5                    -5.5                   -24.8
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                  -48.2                    -0.3                    -3.5
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                  -29.4                    -9.3                    -2.1
             Bering Sea          Sea of Okhotsk              Total Area
                   -0.7                    -2.8                   -75.3
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on June 21, 2013, 03:30:57 PM
Looking at the graph, it is now getting clear to me that the CT area is lagging two days compared with this calculation and the Jaxa/IJIS data.

First the date tag included with the CT data is already the day before yesterday.
Second when computing the cross correlations between changes in my data and those in CT area we get a peak at -1 (indicating my calculation leads):

(https://sites.google.com/site/arctischepinguin/home/amsr2/grf/amsr2-ct-area-ccf.png)

Total makes two days.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on June 22, 2013, 08:39:08 AM
Midsomer update:

extent: -88k1  Mostly Hudson, declines for Barentsz, Kara,Laptev. Also Greenland sea and CAA. Increase for Baffin.

area:-53k7 Also here it is Hudson, but CAB is good second together with CAA and Greenland sea. Baffin has the big increase, with ESS.

The details:
Code: [Select]
Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   -5.2                     3.3                    -3.8
               Kara Sea             Barents Sea           Greenland Sea
                  -11.5                    -4.6                    -8.0
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   11.0                     0.1                   -67.7
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   -4.6                    -0.3                     4.4
             Bering Sea          Sea of Okhotsk            Total Extent
                    0.1                    -1.2                   -88.1

Area:
           Arctic Basin       East Siberian Sea              Laptev Sea
                  -49.8                    31.5                     0.2
               Kara Sea             Barents Sea           Greenland Sea
                   -5.4                    -0.6                   -13.1
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   44.5                     0.0                   -73.2
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                  -19.7                    14.9                    17.4
             Bering Sea          Sea of Okhotsk              Total Area
                    1.4                    -1.8                   -53.7
Title: Re: Home brew AMSR2 extent & area calculation
Post by: jdallen on June 22, 2013, 10:33:30 AM
Baffin *Increase*!?

How?
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on June 22, 2013, 11:34:56 AM
Baffin *Increase*!?

How?

divergence (negative)?

See attached, red pixels have concentration going below 15%, blue pixels passing the 15% the other direction.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on June 23, 2013, 08:20:37 AM
Update 20130622:

extent: -67k9
area: -26k0

Baffin and Hudson are declining fast. Kara and Barentsz a bit less.
Gainers are Greenland sea, ESS, Beaufort and Chukchi.

the details:
Code: [Select]
Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                    1.8                     2.5                    -2.3
               Kara Sea             Barents Sea           Greenland Sea
                   -9.7                    -8.1                    18.7
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                  -32.6                     0.2                   -37.3
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                    3.4                     1.0                    -2.9
             Bering Sea          Sea of Okhotsk            Total Extent
                   -1.7                    -0.8                   -67.9

Area:
           Arctic Basin       East Siberian Sea              Laptev Sea
                  -15.2                    35.3                    -0.9
               Kara Sea             Barents Sea           Greenland Sea
                   -5.9                    -4.8                    43.3
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                  -69.9                     0.1                   -21.8
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   -3.1                    13.0                     5.0
             Bering Sea          Sea of Okhotsk              Total Area
                   -1.2                    -0.1                   -26.0
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on June 24, 2013, 08:23:42 AM
Extent: -50k1
Area: +28k4

Decline mostly Hudson and Barentsz
Increases for Laptev and ESS.
CAB has large increase in area but small decrease in extent

The details:

Code: [Select]
Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   -3.6                     3.1                     7.2
               Kara Sea             Barents Sea           Greenland Sea
                   -4.9                   -11.5                    10.6
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -1.3                     0.0                   -42.9
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   -2.2                    -0.4                    -4.8
             Bering Sea          Sea of Okhotsk            Total Extent
                   -0.2                     0.7                   -50.1

Area:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   59.1                    11.9                    16.1
               Kara Sea             Barents Sea           Greenland Sea
                   -3.5                    -9.1                    -4.2
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                  -12.6                     0.0                   -50.1
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   16.8                     9.3                    -5.6
             Bering Sea          Sea of Okhotsk              Total Area
                   -0.5                     0.7                    28.4
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on June 25, 2013, 08:27:04 AM
Extent: -144k3
Area: -112k4

Biggest declines in Hudson, Baffin and Greenland sea. Further Barents (what is left of it), Kara and Laptev.

Still little movement or even increases in CAB, ESS and Beaufort.

The details:

Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                    1.3                    -0.1                   -11.2
               Kara Sea             Barents Sea           Greenland Sea
                  -20.8                    -5.8                   -38.7
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                  -38.3                     0.3                   -29.6
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                    5.5                     1.4                    -4.0
             Bering Sea          Sea of Okhotsk            Total Extent
                   -2.2                    -2.0                  -144.3

Area:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   66.8                     9.5                    -2.4
               Kara Sea             Barents Sea           Greenland Sea
                  -24.7                    -7.3                   -48.8
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                  -38.5                     0.3                   -47.9
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                  -11.0                     3.7                    -8.5
             Bering Sea          Sea of Okhotsk              Total Area
                   -1.7                    -1.9                  -112.4
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on June 26, 2013, 08:22:05 AM
Extent: -122k3
Area: -181k6

Declines almost in all regions. This day, also declines in Chucki and Beaufort. ESS is the most stubborn  with a very small increase in extent and a decline in area.

The details:

Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   -1.4                     0.2                   -17.0
               Kara Sea             Barents Sea           Greenland Sea
                  -22.6                    -7.7                    -0.3
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                  -30.7                     0.0                   -26.0
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                    3.4                    -1.8                   -14.3
             Bering Sea          Sea of Okhotsk            Total Extent
                   -0.4                    -3.7                  -122.3

Area:
           Arctic Basin       East Siberian Sea              Laptev Sea
                  -28.9                    -3.2                   -14.7
               Kara Sea             Barents Sea           Greenland Sea
                  -48.8                    -4.7                    11.5
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                  -32.7                     0.1                   -25.4
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   -1.9                   -11.3                   -15.4
             Bering Sea          Sea of Okhotsk              Total Area
                   -0.6                    -5.6                  -181.6
Title: Re: Home brew AMSR2 extent & area calculation
Post by: jdallen on June 26, 2013, 08:28:47 AM
Extent: -122k3
Area: -181k6

Declines almost in all regions. This day, also declines in Chucki and Beaufort. ESS is the most stubborn  with a very small increase in extent and a decline in area.


No surprises here at all, as far as I'm concerned.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on June 27, 2013, 08:33:49 AM
Extent: -171k5
Area: -124k

Extent is lost in all regions with ice cover. Biggest decline Baffin and Greenland sea.
Area is gained in Hudson and Kara, a big loss in the CAB.

The details:

Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   "-7"                  "-5.8"                 "-10.3"
               Kara Sea             Barents Sea           Greenland Sea
                "-13.2"                   "0.5"                 "-48.6"
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                "-38.3"                   "0.1"                  "-2.7"
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                 "-7.1"                   "-15"                 "-18.5"
             Bering Sea          Sea of Okhotsk            Total Extent
                 "-0.6"                    "-5"                "-171.5"

Area:
           Arctic Basin       East Siberian Sea              Laptev Sea
                "-33.5"                  "-9.2"                    "-3"
               Kara Sea             Barents Sea           Greenland Sea
                 "16.4"                  "-2.9"                 "-46.8"
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                "-24.1"                  "-0.1"                  "30.2"
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                "-15.2"                 "-13.5"                 "-18.3"
             Bering Sea          Sea of Okhotsk              Total Area
                 "-0.4"                  "-3.8"                  "-124"
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on June 27, 2013, 09:27:09 AM
Studying the images I find that to days source data contains rather a lot of what I call "ghost" ice: fileds of ice appearing for single days in area's that are crealy ice free.

For today this affects mostly the Barentsz region, the extent increase in not real and more something like -5k. The real total extent decrease is about -185k. Other regions and SIA are less affected.

I will set the parameters controlling the "ghost ice removal" procedure a bit tighter.  Tomorrows data will be based on those: having to recompute the whole time series takes several hours.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Tor Bejnar on June 27, 2013, 01:15:32 PM
Thanks, Wipneus, for doing this work. Although I'm not doing anything with your data, I've been checking in almost daily.  At some point I hope to find time to graph this data and compare to CT.
Mostly, I want you to know how appreciative I am (and I'm sure others are).
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on June 27, 2013, 01:32:41 PM

 At some point I hope to find time to graph this data and compare to CT.


Thank you for your kind words.

In the top post you will find the updated extent and area (including the current CT area) graphs.

Do not go to https://sites.google.com/site/arctischepinguin/home/amsr2 (https://sites.google.com/site/arctischepinguin/home/amsr2) just yet. This is where I hope give these things a more permanent place.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Tor Bejnar on June 27, 2013, 01:47:42 PM
Thanks,
I hadn't noticed that the graphs are kept up-to-date.  My (hopeful) future graphs, I was thinking when I wrote just above, would be the Central Arctic or Barentsz or Greenland Sea data.

Arctic ice is healthy for children and other living things.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on June 27, 2013, 05:57:51 PM
Well about the regional area. Here are two attachments (need to be logged in to see them).
The first one compares regional CT with this calculation. As you can see there is positive differences for the CAB and (lesser) the other regions within the Arctic Ocean. Differences in the outer, lower latitudes tend to be negative.

In the second attachment, I dit use nominal grid cell areas (3.125*3.125 km2) instead of adjusted for the sterographic projection. The differences are much smaller (except st Lawrence and CAA).

So it is my hypothesis that CT does not use the real grid cell area's. I have send an email last week, but did no get an answer yet.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on June 28, 2013, 08:45:12 AM
To days update:

Extent -99k2
Area: -111k2


CAB, Beaufort and ESS still slow. Other regions continue the decline, including today the CAA.

The details:

Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   -7.8                     0.0                    -7.4
               Kara Sea             Barents Sea           Greenland Sea
                   -4.4                    -6.7                    -4.2
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                  -21.6                     0.4                   -34.5
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   -5.7                    -1.1                    -2.7
             Bering Sea          Sea of Okhotsk            Total Extent
                    0.9                    -4.3                   -99.2

Area:
           Arctic Basin       East Siberian Sea              Laptev Sea
                    3.5                    -3.6                    -6.2
               Kara Sea             Barents Sea           Greenland Sea
                  -19.7                    -3.4                     0.9
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   12.5                     0.4                   -78.5
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                  -17.4                     2.8                    -0.9
             Bering Sea          Sea of Okhotsk              Total Area
                    0.9                    -3.6                  -112.2
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on June 29, 2013, 08:29:04 AM
To days update:

Extent: -105k1
Area: -118k4

Big declines in Kara, Baffin and Greenland sea. Increase in CAA. ESS is starting to decline. Other regions keeping it easy, including the Hudson that was such a big runner the last week.

Details:

Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   -1.5                    -3.1                    -3.3
               Kara Sea             Barents Sea           Greenland Sea
                  -22.2                    -2.5                   -35.8
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                  -34.7                    -0.2                    -4.6
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                    7.5                    -0.5                    -1.4
             Bering Sea          Sea of Okhotsk            Total Extent
                   -1.0                    -1.7                  -105.1

Area:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   -4.9                    -6.5                   -10.2
               Kara Sea             Barents Sea           Greenland Sea
                  -41.4                    -1.8                   -31.4
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                  -35.1                     0.0                     3.8
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   10.0                     0.8                     0.6
             Bering Sea          Sea of Okhotsk              Total Area
                   -0.6                    -1.8                  -118.4
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on June 29, 2013, 09:05:07 AM
Here is the situation around Kara. Red pixels indicate extent decreased, blue increased.

It is still very peripheral ice that is melting. Just nibbles at the central Arctic.

(picture attached, need to be logged in to see)

Title: Re: Home brew AMSR2 extent & area calculation
Post by: ChrisReynolds on June 29, 2013, 09:17:49 AM
Wipneus,

If I haven't commented, it's not because I'm not reading, it's because you're doing such a good job it leaves little for me to say. I'll keep reading as long as you keep posting.

Thanks.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Tor Bejnar on June 29, 2013, 03:15:10 PM
Thanks for the regional graphs, Wipneus.  It is curious that line sets in some regions diverge consistently.  My initial reaction was "Are the areas measured the same?" (North Pole hole? Hudson Bay/Can. Arch. boundary?? Fresh water lakes in Can.Arch.?)  I'm guessing, though, that you have quite a tighter hold on possibilities than I have!
Title: Re: Home brew AMSR2 extent & area calculation
Post by: danp on June 29, 2013, 03:30:25 PM
Wipneus,

If I haven't commented, it's not because I'm not reading, it's because you're doing such a good job it leaves little for me to say. I'll keep reading as long as you keep posting.

Thanks.

100% agree.  This has been an incredibly useful project and I've been watching this data eagerly alongside other daily measures.

-Dan
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Neven on June 29, 2013, 09:51:42 PM
Same here, Wip. This is great stuff. I can stop watching day-to-day changes by comparing UB SIC maps.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on June 30, 2013, 08:38:24 AM
Update:

Extent: -90k5
Area: -57k

Biggest decline in Greenland sea, but that is an area with the net balancing with even bigger increases and declines.  Further declines on one side Baffin and CAA and on the other side Kara and Laptev. ESS and Beaufort are quit.
Note the big decline in area for Chukchi.
CAB is making a start now: it is mostly on the border with Barentsz that is "virtually" ice free but also a few pixels within the pack near the side of Chukchi. See if that is the beginning of a "hole".

Details:

Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   -8.5                     0.6                    -9.4
               Kara Sea             Barents Sea           Greenland Sea
                  -11.5                    -2.4                   -28.6
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                  -10.8                    -0.4                    -8.0
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   -9.2                     2.4                    -3.1
             Bering Sea          Sea of Okhotsk            Total Extent
                    0.0                    -1.4                   -90.4

Area:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   -7.2                    -4.4                    -8.4
               Kara Sea             Barents Sea           Greenland Sea
                   -0.2                    -0.9                    10.7
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                  -16.5                    -0.4                     4.2
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   -1.2                    -2.9                   -30.7
             Bering Sea          Sea of Okhotsk              Total Area
                   -0.1                     0.9                   -57.0
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on June 30, 2013, 09:02:26 AM
Region of the day is Greenland sea. Ice creates blues where it moves to and leaves reds in its wake. The reds in the top of the image are actually counted as in the Arctic Basin.

(attached, need to be logged in to see).

 
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on June 30, 2013, 10:31:55 AM
Thanks for the regional graphs, Wipneus.  It is curious that line sets in some regions diverge consistently.  My initial reaction was "Are the areas measured the same?" (North Pole hole? Hudson Bay/Can. Arch. boundary?? Fresh water lakes in Can.Arch.?)  I'm guessing, though, that you have quite a tighter hold on possibilities than I have!

Tor,

First I am happy that most regions are doing very well: maximum areas are very close. That includes ALL regions within the Arctic basin.

About the Canadian Archipelago: the region graph:

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Farctic.atmos.uiuc.edu%2Fcryosphere%2FIMAGES%2Fregion.mask.gif&hash=27d29e652d91a46d975576c2bea1fd6b)

counts 1183 pixels in "CAA grey". That is 1183*25^2= 0.74 Mm2
But the max ice in CAA is about 0.6 Mm2

Clearly not all pixels are counted in the CT regional area. Some disconnected pixels may be dropped as virtual lakes, in the high resolution maps that I use the are connected to open sea.

CT still counts positive area for st.Lawrence, I don't see how that is possible.

I will try again to contact CT in a week or so.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 01, 2013, 08:27:36 AM
to days update:

Extent: -123k2
Area: -179k3

Greenland sea, Hudson, Baffin and Kara are continuing their decline. CAA and Chukch have joined. Slow in Beaufort, ESS and an increase  in Laptev.

In the slow regions, CAB and Beaufort have lost considerable Area.

the details (values in 1000 km2):

Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   -1.7                    -2.4                     6.4
               Kara Sea             Barents Sea           Greenland Sea
                  -20.9                     1.3                   -25.2
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                  -14.7                    -0.1                   -35.1
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                  -10.7                    -1.0                   -16.2
             Bering Sea          Sea of Okhotsk            Total Extent
                    0.2                    -3.0                  -123.2

Area:
           Arctic Basin       East Siberian Sea              Laptev Sea
                  -71.9                     1.7                     9.7
               Kara Sea             Barents Sea           Greenland Sea
                  -11.0                     1.4                   -23.1
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -0.1                    -0.1                   -57.0
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                  -37.4                   -10.4                    20.7
             Bering Sea          Sea of Okhotsk              Total Area
                    0.5                    -2.2                  -179.3
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 01, 2013, 08:33:08 AM
Region of the day is Hudson Bay. Still plenty of extent that will have to go.

Image attached, need to log in to see.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Artful Dodger on July 01, 2013, 08:43:43 AM
Amazing results, Wipneus!

Since the Central Basin lost 79 km2 in SIA but is so large geographically, I wonder I you have a similar map for the Central Basin?

Thanks for taking on this project. It's a wonderful resource for our community!  8)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 01, 2013, 09:42:37 AM
Lodger, attached is the party of CAB that have delta extents.

Most of them is the Barentsz and Greenland melt that is not bothering about region boundaries and is now eating into the CAB.

The pixels within the CAB that change have been until so far very volatile, disappearing and reappearing.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 01, 2013, 10:17:59 AM
Having developed a calculation of extent and area from gridded sea ice concentration makes it easy to adapt to other products as well.

I am looking right now in Uni Hamburg's ssmis product: same people of the amsr2 sea ice concentration map, same algorithm.
http://icdc.zmaw.de/seaiceconcentration_asi_ssmi.html?&L=1 (http://icdc.zmaw.de/seaiceconcentration_asi_ssmi.html?&L=1)

The Special Sensor Microwave Imager/Sounder (SSMIS) is an instrument on a Defense Meteorological Satellite Program (DMSP) satellite:
http://nsidc.org/data/docs/daac/ssmis_instrument/ (http://nsidc.org/data/docs/daac/ssmis_instrument/)

SSMIS does seem to be comparable with the AMSR2 but with a lower resolution (12.5 km). In spite of the resolution difference my preliminary results seem to comparable, with the AMSR2 giving a somewhat smoother result.

Attached (need to be logged in) is an image of the extent changes a year ago.
It looks quiet compared with to days state of the Arctic sea ice.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 01, 2013, 03:35:55 PM
Having ssmis data for 2012, so how does 2013 compares with 2012?

Picking day 181 for 2012 and 2013.

Extent: +593k and area +266k

Ignoring the Hudson and Baffin (320k extent 113k area) most of the positive differences are in Beaufort and Kara. Large negative differences in Greenland sea and  Laptev.
Smaller differences for CAA (positive) balances Chukchi in the negative. Other regions can be ignored.

The details (in 1000 km2):



#### EXTENT ASMR2 3.125 km - SSMIS 12.5 km 2013 DAY 181 ####

           Arctic Basin       East Siberian Sea              Laptev Sea
                   27.5                   -10.8                  -107.0
               Kara Sea             Barents Sea           Greenland Sea
                  418.7                    -1.1                  -265.0
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                  115.4                    -9.0                   204.9
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   54.6                   209.2                   -58.6
             Bering Sea          Sea of Okhotsk            Total Extent
                   -3.9                    18.6                   593.4

#### AREA ASMR2 3.125 km - SSMIS 12.5 km 2013 DAY 181 ####

           Arctic Basin       East Siberian Sea              Laptev Sea
                  -96.7                    -8.3                  -104.8
               Kara Sea             Barents Sea           Greenland Sea
                  355.6                     0.1                  -167.4
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   68.8                    -7.4                    45.2
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                    2.9                   213.2                   -48.9
             Bering Sea          Sea of Okhotsk              Total Area
                   -2.2                    15.5                   265.6

####
Title: Re: Home brew AMSR2 extent & area calculation
Post by: jdallen on July 01, 2013, 07:06:16 PM
Interesting.  Looks like the lions share of the difference is in three peripheral areas... Kara sea, Baffin Bay, and Hudson Bay.  The Beaufort is less than 1/4 of the difference.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 02, 2013, 08:21:31 AM
Update, I have added the ssmis 2012 data to the graphs. Who is still saying 2013 cannot match 2012?

Extent: -142k9
Area: -44k3

Beaufort and ESS show now considerable decline (compared with their behavior till now). Laptev doing the opposite, a small increase. Further BAU.

The details:

Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   -7.1                    -7.3                    10.4
               Kara Sea             Barents Sea           Greenland Sea
                  -29.3                    -1.2                   -16.2
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                  -33.1                     0.3                   -35.7
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                    1.6                   -14.8                    -9.7
             Bering Sea          Sea of Okhotsk            Total Extent
                    0.1                    -0.9                  -142.9

Area:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   44.9                    -5.1                    10.2
               Kara Sea             Barents Sea           Greenland Sea
                  -32.3                    -0.7                   -24.2
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                  -42.3                     0.1                    33.4
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                  -18.7                    -1.5                    -7.1
             Bering Sea          Sea of Okhotsk              Total Area
                   -0.2                    -0.7                   -44.3
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 02, 2013, 08:30:17 AM
Region(s) of the day are ESS & Laptev Sea. It is a balance between reds and blues, with the blues in the majority today in Laptev and the reds in ESS.

(Image attached, need to be logged in to see)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 02, 2013, 08:38:16 AM
Introducing the regional graphs. These and the Pan Arctic graphs can also be viewed (and are updated as we go) in the top post: https://forum.arctic-sea-ice.net/index.php/topic,382.0.html (https://forum.arctic-sea-ice.net/index.php/topic,382.0.html)

(https://sites.google.com/site/arctischepinguin/home/amsr2/grf/amsr2-extent-regional.png)

(https://sites.google.com/site/arctischepinguin/home/amsr2/grf/amsr2-area-regional.png)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: wanderer on July 02, 2013, 10:41:34 AM
Wow, great work!

When will PIOMAS update?
Can't wait to see the new Volume update!
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Artful Dodger on July 02, 2013, 11:24:31 AM
Hi Wipneus,

The Regional SIA area graphs are brilliant. Adios, CT!  8)

I see that your plot for CAB SIA bottoms out after mid-August 2012 at around 3.2 M km2.

Nominally, CT bottomed out at around 2.2 by mid-September.

Can you provide tabular data for 2012/13 CAB SIA from SSMIS?

*** WATCH THIS SPACE! ***
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Artful Dodger on July 02, 2013, 11:46:25 AM
Introducing the regional graphs.
(https://sites.google.com/site/arctischepinguin/home/amsr2/grf/amsr2-extent-regional.png)

Hi again, Wipneus

Just a technical question regarding the regional boundaries for the Canadian Archipelago & Baffin Bay/Newfoundland Sea.

I see that the maximum SIE differs from 2012 to 2013 for the CA differs by a constant amount at SIE maximum. I wonder if you've accidentally changed the geographic division between the CA and Baffin Bay between the two years?

The baseline max SIE at ~100% concentration should be the same in both years, absent any persistent and stable polynya. This is the behavior West of the CA in the Beaufort sea for example, which indicates that border is consistent between 2012/13.

I do see that on the East boundary of the CA, Baffin Bay has the opposite but equal magnitude difference between the two years. However it is difficult to compare 2012/13 since the BB region never reaches 100% SIE over the Winter.

So, i leave this interesting technical puzzle in your capable hands ;)

Thanks once more for the excellent work.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Richard Rathbone on July 02, 2013, 01:22:37 PM
The good stuff just keeps coming. Red pixel animations in the pipeline?

Any chance of extending the axis so the lines don't fall off the bottom of the CAB graph?

You show Hudson as being virtually identical with last year while CT has it about a week behind from my reading of their graph. Is this a case of measurement differences or something like them actually only showing 360 days where they say its a year?
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Pmt111500 on July 02, 2013, 02:14:19 PM
Excellent work. One point I'm curious about is are you planning to divide the CAB to the Canada Basin and Eurasian (was it Nares?) Basin sometime? Hydrographically they are somewhat different (at least in the deep parts) from each other so there might be reason to? I'll stick to the CT SIA still, but this is mainly because I cannot automate or program stuff to hadle these amounts of data. But maybe sometime. Thanks for inspiration.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 02, 2013, 07:03:07 PM
Thanks people. I have been on the road most of the day, and no time to properly respond to all of your comments and questions until tomorrow.

For now just this:

Minimum ssmis 2012 CAB area and extent are 2.570968 (Sep 17) and 2.796018 Mm2 (Sep 16)
Minimum ssmis 2012 Total area and extent are 2.872789 (Sep 4) and 3.178891 Mm2 (Sep 13)

(dates may be off by a few days, but that should affect all dates in the same way)

Hmm, rather strange isn't it?

Title: Re: Home brew AMSR2 extent & area calculation
Post by: dbostrom on July 02, 2013, 09:30:29 PM
Looking at these (truly excellent approach!) graphs there seems little difference between 2012 and this year.

I don't have a sense of the area covered by each region. Perhaps it would be worth adding something in the way of a commonly scaled disk or other visual indicator to each plot so that the eye can see at a glance the relative significance of the various pieces?
Title: Re: Home brew AMSR2 extent & area calculation
Post by: dree12 on July 02, 2013, 10:26:55 PM
Thanks people. I have been on the road most of the day, and no time to properly respond to all of your comments and questions until tomorrow.

For now just this:

Minimum ssmis 2012 CAB area and extent are 2.570968 (Sep 17) and 2.796018 Mm2 (Sep 16)
Minimum ssmis 2012 Total area and extent are 2.872789 (Sep 4) and 3.178891 Mm2 (Sep 13)

(dates may be off by a few days, but that should affect all dates in the same way)

Hmm, rather strange isn't it?

Is this perhaps related to differing methods for handling the pole hole?
Title: Re: Home brew AMSR2 extent & area calculation
Post by: LarsBoelen on July 02, 2013, 11:31:49 PM
Wow Wipneus, I haven't seen such a detailed analyses of the Polar Ice Melt. What I take away from these graphs is this : a lot of the regions are lagging 2012 but are going to melt out anyways, maybe a bit later than last year, but that doesn't matter for the final total minimum extent/area. The regions that will have residual ice (like Central & Greenland) are either on track or ahead of 2012. So based on these insights I would say that the race is on for beating 2012!
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 03, 2013, 07:03:07 AM

I see that your plot for CAB SIA bottoms out after mid-August 2012 at around 3.2 M km2.

Nominally, CT bottomed out at around 2.2 by mid-September.

Can you provide tabular data for 2012/13 CAB SIA from SSMIS?


All regions have the same scale division (0.2Mm2/div) to make them comparable. It is clear that before September something will need to be done to keep CAB in the range.

Data will be provided soon, preliminary CAB SIE and SIA are for now:
https://sites.google.com/site/arctischepinguin/home/amsr2/data/ssmis_CAB_EA.dat (https://sites.google.com/site/arctischepinguin/home/amsr2/data/ssmis_CAB_EA.dat)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 03, 2013, 07:14:41 AM

Just a technical question regarding the regional boundaries for the Canadian Archipelago & Baffin Bay/Newfoundland Sea.

I see that the maximum SIE differs from 2012 to 2013 for the CA differs by a constant amount at SIE maximum. I wonder if you've accidentally changed the geographic division between the CA and Baffin Bay between the two years?


It is a consequence of the 16 times difference in grid cell area. Pixels in the 12.5 km grid that are "mostly" land will be not counted area in the SSMIS calculation, while in the AMSR2 calc the pixels over sea are just counted. The difference with CT, which uses, I think, a 25km grid is even bigger.
See also https://forum.arctic-sea-ice.net/index.php/topic,382.msg8534.html#msg8534 (https://forum.arctic-sea-ice.net/index.php/topic,382.msg8534.html#msg8534)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 03, 2013, 07:31:05 AM
Any chance of extending the axis so the lines don't fall off the bottom of the CAB graph?

You show Hudson as being virtually identical with last year while CT has it about a week behind from my reading of their graph. Is this a case of measurement differences or something like them actually only showing 360 days where they say its a year?

I am happy with the CAB graph at the moment: it is a compromise. Yet soon I will have to do something, I am looking at the technical possibilities.

It is difficult to see, but I am inclined to think we are seeing CT disagreeing about the Hudson differences. Perhaps that is to be expected, there are more questions about CT.
I have older screenshots from the CT regional graphs. I will see if I can make an overlay.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 03, 2013, 07:40:29 AM
Excellent work. One point I'm curious about is are you planning to divide the CAB to the Canada Basin and Eurasian (was it Nares?) Basin sometime? Hydrographically they are somewhat different (at least in the deep parts) from each other so there might be reason to?

No plans. In my understanding Arctic sea ice is isolated from the deep ocean by the halocline, I would expect the geography at the surface to be more important.

I could imagine dividing the CAB into the pole area (>80 deg latitude) and  east-, west-, Atlantic sub-regions.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Bob Wallace on July 03, 2013, 07:46:48 AM
Thanks, Wipneus.  These regional graphs contain so much more information that the 'year in review' set we have now. 

Neven- can we get these on a page accessible from the main graphs page?

What they really show me is what is happening in the CAB.  I've been wondering if later melting in the areas that will go to zero might hold back center melt.  Looks like they probably won't.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 03, 2013, 07:49:11 AM

I don't have a sense of the area covered by each region. Perhaps it would be worth adding something in the way of a commonly scaled disk or other visual indicator to each plot so that the eye can see at a glance the relative significance of the various pieces?

Doug, I made sure the scale divisions are all the same (0.2 Mm2/div), so they are comparable. As some have noted/objected the scale of Arctic Basin does not include zero. Pity, I am looking into it.
For the moment note that CAB is more than three time the area of any of the other regions, but less than a third of the total.
Region division is the same as CT uses:
http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/region.mask.gif (http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/region.mask.gif)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 03, 2013, 07:56:31 AM
Thanks people. I have been on the road most of the day, and no time to properly respond to all of your comments and questions until tomorrow.

For now just this:

Minimum ssmis 2012 CAB area and extent are 2.570968 (Sep 17) and 2.796018 Mm2 (Sep 16)
Minimum ssmis 2012 Total area and extent are 2.872789 (Sep 4) and 3.178891 Mm2 (Sep 13)

(dates may be off by a few days, but that should affect all dates in the same way)

Hmm, rather strange isn't it?

Is this perhaps related to differing methods for handling the pole hole?

Maybe I was too terse. What is thought was strange is that the Central Arctic melts until later than lower latitudes. Now I look closer, it looks that it is the Greenland Sea that is causing the growth. Increase in Fram export.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: dbostrom on July 03, 2013, 07:57:03 AM
Quote
Doug, I made sure the scale divisions are all the same (0.2 Mm2/div), so they are comparable.

Ah, of course. Sorry!

This is an excellent visualization. Thank you. I'm almost afraid to ask how much work is required to produce it.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 03, 2013, 08:01:46 AM
What I take away from these graphs is this : a lot of the regions are lagging 2012 but are going to melt out anyways, maybe a bit later than last year, but that doesn't matter for the final total minimum extent/area. The regions that will have residual ice (like Central & Greenland) are either on track or ahead of 2012. So based on these insights I would say that the race is on for beating 2012!

Exactly what I see myself!

Only Beaufort might be seen as a problem: it took 2 months to melt out in 2012. That happened in June and July, will have to happen now in July and August. A slight disadvantage with insolation that needs to be compensated.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 03, 2013, 08:07:53 AM
Quote
Doug, I made sure the scale divisions are all the same (0.2 Mm2/div), so they are comparable.

Ah, of course. Sorry!

This is an excellent visualization. Thank you. I'm almost afraid to ask how much work is required to produce it.

Not much,

- A few commands on the computer to fetch data and draw the plots;
- Upload the plots to google sites;
- Present the results on the forum.

The last step takes by far the most time.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 03, 2013, 08:28:50 AM
Update.

Extent: -178k9    (+363k7 compared with 2012)
Area: -151k1    (+229k compared with 2012)

Beaufort (finally) starts declining. Most regions are decling now, Chukchi and ESS slow, and Greenland sea shows some  growth.

Graphs are updated and to be found in the top post.

The details:

Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   -8.9                    -0.8                    -4.9
               Kara Sea             Barents Sea           Greenland Sea
                  -42.4                    -1.4                    16.3
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                  -15.8                    -0.1                   -88.6
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                  -17.1                   -15.3                     2.0
             Bering Sea          Sea of Okhotsk            Total Extent
                   -0.4                    -1.4                  -178.9

Area:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   13.3                     4.1                    -1.5
               Kara Sea             Barents Sea           Greenland Sea
                  -25.8                    -1.3                     3.9
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                    3.6                    -0.1                  -111.1
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   -3.3                   -21.0                   -10.1
             Bering Sea          Sea of Okhotsk              Total Area
                   -0.5                    -1.6                  -151.4

Title: Re: Home brew AMSR2 extent & area calculation
Post by: dbostrom on July 03, 2013, 08:38:36 AM
Looking at the graphs, I see 14 areas of interest of which 4 appear to be lagging 2012, with at least one of those lags not looking very significant.  That's why I was wondering (uselessly, not having scrutinized the Y-scale) about relative weight of the areas shown.

Thought-provoking.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 03, 2013, 08:39:30 AM
Regions of the day CAA and Beaufort. Also here the melting season has begon.

(image attached, need to be logged in to see)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Neven on July 03, 2013, 08:55:51 AM
Neven- can we get these on a page accessible from the main graphs page?

I'm thinking about how to incorporate this stuff somehow, somewhere. Wipneus, if you have any ideas or wishes, let me know.

These regional maps you're posting with the red and blue would be a great addition to the 'regional graph of the week' section of ASI updates. I'll send you a request in a couple of days.

Really great work. Do the folks from Uni Bremen still show interest in what you're doing?
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Artful Dodger on July 03, 2013, 09:42:16 AM
Hi Wipneus,

What is the total area defined as the "Canadian Archipelago" region?

Is it 0.7 M km2? 0.8 M km2?

Thanks.  8)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 03, 2013, 10:18:19 AM
Hi Wipneus,

What is the total area defined as the "Canadian Archipelago" region?

Is it 0.7 M km2? 0.8 M km2?

Thanks.  8)

The amsr2 3.125 km grid counts  0.7917134 Mm2
The ssmis 12.5 km grid counts counts 0.7034836 Mm2

Again, I am using exactly the same mask but the source SSMIS data has a bit less sea area than the AMSR2 data.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Frivolousz21 on July 03, 2013, 10:23:21 AM
First off Great work.

I have to point out however that the difference between 12.5km grids and 3.125km as you know is quite large.

So 2012 even though far less diapered would be surely lower with 3.125km grids vs 12.5km2 grids and a higher res scanner. 

So it's not an apples to apples comparison.  If this has already been posted, I apologize. 
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 03, 2013, 10:50:07 AM
First off Great work.

I have to point out however that the difference between 12.5km grids and 3.125km as you know is quite large.

So 2012 even though far less diapered would be surely lower with 3.125km grids vs 12.5km2 grids and a higher res scanner. 

So it's not an apples to apples comparison.  If this has already been posted, I apologize.

Somewhere I did mention that the ssmis and amsr2 results seem to be comparable, at least for the 2013 development. My understanding is now that the different algorithms used are far more important than grid size: both the ssmis and amsr2 data that I use are calculated with the ASI (ARSTIST Sea Ice) algorithm. As far as I know IJIS Jaxa use "Bootstrap" and NSIDC "NASA Team" algorithm.

I realize I never showed my evidence. Here attached (need to be logged in to see).

PS. SSMIS data has not been updated since Jun 20

Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 03, 2013, 10:59:12 AM
And here is area 3.125 km compared with 12.5 km.

(attached, need to be logged in to see)

Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 03, 2013, 11:03:57 AM
PPS. Please have a look at the comparisons between the 3.125km AMSR2 area with 25km CT regional area attached here:

https://forum.arctic-sea-ice.net/index.php/topic,382.msg8378.html#msg8378

Only the st. Lawrence seems a mystery.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Peter Ellis on July 03, 2013, 12:26:18 PM
One way of double-checking the effect of resolution independently of different sensors / wavelengths / algorithms would be to downgrade the 3.125km data by various factors and see what happens.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 03, 2013, 12:33:59 PM
One way of double-checking the effect of resolution independently of different sensors / wavelengths / algorithms would be to downgrade the 3.125km data by various factors and see what happens.

Yes. I have this definitely planned after the melt season. As it is, we have only half of a year 3.125km data, and missing the most interesting part.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: slow wing on July 03, 2013, 01:29:55 PM
Thank you for doing this, Wipneus. It is informative and fascinating.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 04, 2013, 08:29:14 AM
Updated:

extent : -131k7 (@ +277k from 2012)
area : -210k4 (@ +62k from 2012)

So we have for the first time a double century for area, and approaching the area levels last year.

CAB especially makes a large downward jump in area, also beaufort substantially declines in area. The extent much less so for these two regions.
Solid decline, both in extent and area for Baffin, CAA and Kara.

I have modified the regional graphs with a widened scale for the CAB (most requested feature). See for instance the top post to view these and other graphs.

The details:

Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   -8.7                    -0.3                    -5.7
               Kara Sea             Barents Sea           Greenland Sea
                  -19.8                    -2.4                   -12.7
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                  -48.1                    -0.2                    -7.5
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                  -21.5                    -1.5                     0.6
             Bering Sea          Sea of Okhotsk            Total Extent
                   -0.5                    -3.3                  -131.7

Area:
           Arctic Basin       East Siberian Sea              Laptev Sea
                  -58.1                    -5.7                    -0.9
               Kara Sea             Barents Sea           Greenland Sea
                  -27.2                    -1.7                    14.9
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                  -43.8                    -0.1                   -10.4
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                  -43.0                   -21.8                    -9.4
             Bering Sea          Sea of Okhotsk              Total Area
                   -0.8                    -2.2                  -210.4
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 04, 2013, 08:48:27 AM
Most interesting region of the day is this part of CAB, Greenland Sea,  Barentsz Sea and Kara.

I showed this a couple of days ago and warned then that the red pixels within the CAB come and go. This time I suspect the holes are here to stay, perhaps the beginning of a "Barents bite".

(image attached. To see, you must be logged in)

Title: Re: Home brew AMSR2 extent & area calculation
Post by: jdallen on July 04, 2013, 08:56:31 AM
Updated:

extent : -131k7 (@ +277k from 2012)
area : -210k4 (@ +62k from 2012)

So we have for the first time a double century for area, and approaching the area levels last year.


This is really starting to play out the way I expected.  Tell me, within the regions, what nature of ice is disappearing?
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 04, 2013, 09:02:08 AM

This is really starting to play out the way I expected.  Tell me, within the regions, what nature of ice is disappearing?

??? nature of ice ???

(caffeine levels are low, have patience )
Title: Re: Home brew AMSR2 extent & area calculation
Post by: jdallen on July 04, 2013, 09:20:53 AM
Quite understood; an unfamiliar American idiom.

Is that area disappearing showing up as large areas of open water, or melting out of inter-floe areas, or some combination?

I expect in some areas (Baffin, Hudson,Kara), the ice over all is just simply disintegrating; how about out side those regions?
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 04, 2013, 10:40:00 AM
It is as you say, Hudson and Baffin do now what Greenland sea does always: disappearing and reappearing over the area with the balance now for those two now to decline.

The CAB is being nibbled from the outside. Ice loss and gain in the middle of the pack have proved short lived until now. I have the idea that the ice-freed area today will grow in the coming days.

(attached image of Hudson and Baffin area, be logged in etc.)

Title: Re: Home brew AMSR2 extent & area calculation
Post by: crandles on July 04, 2013, 12:04:06 PM
Most interesting region of the day is this part of CAB, Greenland Sea,  Barentsz Sea and Kara.

I showed this a couple of days ago and warned then that the red pixels within the CAB come and go. This time I suspect the holes are here to stay, perhaps the beginning of a "Barents bite".


Great work as always Wipneus.

Is this year going to be the first appearance of the Laptev Turkey? (where it is a gobble not a bite)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 05, 2013, 08:34:52 AM
Update 20130704,

Extent : -192k4 (+180 vs 2012)
Area: -114k2 (+79 vs 2012)

The day to day changes are now bigger than the 2012/2013 difference. That is according to these sea ice concentration products, both based on the ASI algorithm.

ALL regions that are not ice-free yet, are now declining. Hudson and Baffin are the largest but about half of the decline come from the other regions. Of those regions CAA and Kara are the biggest melters.

The details (in 1000 km2)

Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   -4.7                    -4.4                    -6.8
               Kara Sea             Barents Sea           Greenland Sea
                  -12.7                     0.0                   -16.4
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                  -28.0                    -0.1                   -89.5
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                  -15.8                    -4.3                    -6.4
             Bering Sea          Sea of Okhotsk            Total Extent
                   -0.7                    -2.5                  -192.3

Area:
           Arctic Basin       East Siberian Sea              Laptev Sea
                    0.0                    -3.3                    -7.6
               Kara Sea             Barents Sea           Greenland Sea
                   -4.4                     0.2                   -10.7
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                  -26.6                    -0.1                   -38.3
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   11.7                    -9.2                   -23.0
             Bering Sea          Sea of Okhotsk              Total Area
                   -0.6                    -2.3                  -114.2
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 05, 2013, 08:49:28 AM
Regions of the day are Laptev and ESS. Net decline has been steady here lately, but the detail shows in Laptev it is still a balance between red and blue.
If the levels are going to follow the 2012 curves, some heavy melting will have to start soon.

(image attached, log in to see)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 05, 2013, 09:23:58 AM
And here is Beaufort, Chukchi. I have marked with ellipses where Jaxa/IJIS AMSR2 ice monitor shows polynya from July 1-4. They are clearly not present here.

(imaged attached, log in to see)



Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 06, 2013, 08:19:09 AM
I cannot update now :-(

A new "feature" was added to my source data. From a new README:

Quote
We apply monthly ocean masks to the data according to the masks used by NSIDC
(http://nsidc.org/data/smmr_ssmi_ancillary/ocean_masks.html (http://nsidc.org/data/smmr_ssmi_ancillary/ocean_masks.html)). These masks are interpolated
to the finer resolution used here and manually corrected for coarse coastlines at the original
25 km resolution.

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!! APPLICATION OF OCEAN MASKS STARTS FROM 6 JULY 2013 !!
!! RE-PROCESSING OF HITHERTO PRODUCED DATA IS ONGOING !!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Unfortunately, this ocean mask seems to be applied upside down making the data quite unusable. I have notified the people from the U-Hamburg about the problem.

ftp://ftp-projects.zmaw.de/seaice/AMSR2/README.txt (ftp://ftp-projects.zmaw.de/seaice/AMSR2/README.txt)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: wanderer on July 06, 2013, 08:21:44 AM
Oh no! I was waiting all morning for your update and if we come closer to 2012...

I cannot update now :-(

A new "feature" was added to my source data. From a new README:

Quote
We apply monthly ocean masks to the data according to the masks used by NSIDC
(http://nsidc.org/data/smmr_ssmi_ancillary/ocean_masks.html (http://nsidc.org/data/smmr_ssmi_ancillary/ocean_masks.html)). These masks are interpolated
to the finer resolution used here and manually corrected for coarse coastlines at the original
25 km resolution.

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!! APPLICATION OF OCEAN MASKS STARTS FROM 6 JULY 2013 !!
!! RE-PROCESSING OF HITHERTO PRODUCED DATA IS ONGOING !!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Unfortunately, this ocean mask seems to be applied upside down making the data quite unusable. I have notified the people from the U-Hamburg about the problem.

ftp://ftp-projects.zmaw.de/seaice/AMSR2/README.txt (ftp://ftp-projects.zmaw.de/seaice/AMSR2/README.txt)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 06, 2013, 09:00:33 AM
Little choice today, the region of the day is Central Arctic.
Little pixels blue and red mostly cancel over a few days.

Below is the filled in "pole hole".

(image attached, log in to see)

 
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 07, 2013, 09:32:46 AM
Update 20130706:

The error in the upstream data corrected now for July 5 and 6. Unfortunately the data file for July 4 is still unusable. I have tried to correct this using a manually made backup, but am only 99% confident that everything is OK now ( For a particular date I compare with previous dates to remove "ghost ice"; the misapplied mask does affect the 5/6 July).

Extent:  +96k5 (+325k vs 2012)
Area: +50.7 (+404k9 vs 2012)

So we have an uptick here, bit unusual after the extremely smooth ride we had for weeks. Also the the SSMIS data have a small uptick for extent (+5k) and minimal decline in area (-3k), so it is probably real, measuring with different satellites

What is noticeable is that the uptick is shown over many regions, Hudson the biggest followed by CAA and Baffin. Only the CAB shows a decline in extent (but increase in area).

The details:
Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   -4.7                     2.0                     4.1
               Kara Sea             Barents Sea           Greenland Sea
                    6.4                     2.9                    13.6
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   13.5                     0.1                    37.9
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   23.7                     0.8                    -5.9
             Bering Sea          Sea of Okhotsk            Total Extent
                    0.4                     1.8                    96.5

Area:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   16.4                    -3.4                    10.4
               Kara Sea             Barents Sea           Greenland Sea
                   -0.9                     2.2                    17.6
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   13.2                     0.0                    -1.4
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   20.1                    -9.0                   -15.5
             Bering Sea          Sea of Okhotsk              Total Area
                    0.2                     0.8                    50.7
>

Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 07, 2013, 09:43:40 AM
Region of the day is Hudson. Large areas are now covered with low concentration ice, near the cutoff of 15%. Small changes have large impacts on the extent measure.

(log in to see the attached image)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Neven on July 07, 2013, 09:48:44 AM
There's some flashing and unflashing in Hudson and Baffin on the UB SIC maps, so maybe that explains the uptick.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 07, 2013, 11:38:56 AM
Attached (log in to see) update of the comparative AMSR2-3.125km SSMIS-12.5km SIE and SIA graphs.
They are not identical, but quite similar.

Title: Re: Home brew AMSR2 extent & area calculation
Post by: AartBluestoke on July 07, 2013, 02:52:52 PM
Every area which is going to melt will melt out at some stage will have a maximum contribution of exactly the same as last year -- 100% of the current ice. Estimating what happens this year is determined by the ice left over.

Last year the following areas melted out: (from the area graph in the first post)
East Siberian Sea
Laptev Sea
Chukchi Sea
- Kara Sea
- Beaufort Sea
= Baffin/Newfoundland Bay
= Hudson Bay
* Barerits Sea
* Bearing Sea
* St Lawrence
* Sea of Okhotsk
 ( - = melting slower than last year)
 ( = = major melt pattern underway, complete melt highly probable)
 ( * = already melted out this year)
---
Other Regions
Arctic Basin
Greenland Sea
Canadian Archipelago

---
In estimating the final minimum extent i think 2 questions should be asked:
a) will the areas which melted out last year melt out this year?
  a1) the East Siberian Sea and the Beaufort sea have the furthest to go, but melting is only just starting.
b) what will be the extent of the surviving ice areas be?
  b1) the majority of this is the arctic basin, and that is running about the same as last year
  b2) could the greenland sea almost completely melt out, as we are below last year by more than the minimum ice area from last year.

if every area that was 100% melted for more than a month last year melts out this year, and the greenland Sea area is worse, the final "do we set a record extent" is almost completely determined by the arctic basin.

I don't know enough ice dynamics/ have enough forecasting ability/... to even make a guess at this, but i can see that keeping exact track of areas which we already know will have 0 contribution at the final minimum could just be adding noise to the system.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: dree12 on July 07, 2013, 04:30:14 PM
  b2) could the greenland sea almost completely melt out, as we are below last year by more than the minimum ice area from last year.

AFAIK the Greenland Sea cannot almost melt out because any open water created will be replaced by ice exiting the Arctic. Greenland is actually likely to be the last sea with summer ice, as in the next few years it is possible the Central Arctic can become a killing ground with only the ice escaping through Greenland surviving.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: BornFromTheVoid on July 07, 2013, 04:47:29 PM
I'd just like to extend my thanks to Wipneus for his work here. It's become part of my morning sea ice routine!

AFAIK the Greenland Sea cannot almost melt out because any open water created will be replaced by ice exiting the Arctic. Greenland is actually likely to be the last sea with summer ice, as in the next few years it is possible the Central Arctic can become a killing ground with only the ice escaping through Greenland surviving.

Hi dree12
The sea ice can melt out on the Greenland sea, though it doesn't happen too often. The end of summer/early Autumns of 2002 and 2003 had just a few thousand km2 of ice left in the Greenland sea at most.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Farctic.atmos.uiuc.edu%2Fcryosphere%2FIMAGES%2Fregion.all.anom.region.5.jpg&hash=8b0242136b8831c147f9dcd7854b5a1c)
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Farctic.atmos.uiuc.edu%2Fcryosphere%2FIMAGES%2FARCHIVE%2F20020830.png&hash=3c9ac6d0fc385dfe7cd6583a5b05512d)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Bob Wallace on July 07, 2013, 07:12:37 PM
Recently we've had little flow of ice through the Fram.  The Greenland Sea is melting out and most likely warming.  This means that ice coming though later in the season will meet warmer water and melt quicker.  A melt accelerating factor.

Extent/area numbers are being held high by the slow start of melting in Kara and Beaufort.  In all other regions melt has been as fast or faster than 2012.  Both Kara and Beaufort are now melting with curves resembling 2012, only with a delayed onset.  Even with a one month delay there is more than enough time to melt out those regions.  2012 hit zero almost two months before the end of the season.

There's no way that 2013 is out of the running for a new record.  It all comes back to the big hole which seems to be developing in the CAB.  If that opens up some serious area loss is going to occur.

Wipneus has provided a most excellent tool for comparing 2013 and 2012. 

(Is regional volume possible?  Even modeled would be a help.  We need to focus our attention on the CAB, this could be the year we realize its weakness.)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: jonthed on July 07, 2013, 07:27:19 PM
Melting in the CAB is surely a bit of an unknown quantity given the unusual distribution and composition of the ice this year.

If the hole opens up then there will be a lot more edge to be eaten away at, if the drift of the ice makes the hole 'close by compressing the outside inward, then the hole won;t open but the area would shrink slightly faster than normal as beside edge melt there would be this inward movement and concentration. Both of these seem to frustrate any attempt to compare with previous years.

To me it seems it is the drift direction in the CAB (that will determine the fate of the hole) that is critical to the total melt this season.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: jdallen on July 07, 2013, 08:56:20 PM
Melting in the CAB is surely a bit of an unknown quantity given the unusual distribution and composition of the ice this year.

Absolutely.  What we do know is, there is a lot more low-albedo surface there to collect energy. The amount and type of cloud cover I think is the key factor there right now.

If the hole opens up then there will be a lot more edge to be eaten away at, if the drift of the ice makes the hole 'close by compressing the outside inward, then the hole won;t open but the area would shrink slightly faster than normal as beside edge melt there would be this inward movement and concentration. Both of these seem to frustrate any attempt to compare with previous years.

It's not really a hole so much as its a vast expanse of ice cubes of varying size and composition (FYI, MYI, & "slush").  The area outside of the hole isn't so much solid "surface" as much as it is simply higher concentration of The Same.  The hole is an illusion of concentration.  Compression won't fully close up the leads, nor will lateral/edge melt be any significant factor in melting except for "slush" and the smallest floes ( < 100M diameter or so, from what I've read).  That said, comparison to previous years is very problematic.  We are uncertain of water temperature, ice thickness, and just how much insolation is actually being captured.

To me it seems it is the drift direction in the CAB (that will determine the fate of the hole) that is critical to the total melt this season.

This I'm not so sure of.  The fact we got a "hole" is the key fact.  That hole closing or opening more simply reflects areas of concentration changing; the open water available to capture heat will remain the same or increase, right up until the refreeze starts.  That there *is* drift carries its own peril; ekman pumping will bring heat to the ice even if the albedo increases. Hope for high, thick clouds, over as wide a region as possible....
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Artful Dodger on July 08, 2013, 08:17:59 AM
To me it seems it is the drift direction in the CAB (that will determine the fate of the hole) that is critical to the total melt this season.

This I'm not so sure of.  The fact we got a "hole" is the key fact.  That hole closing or opening more simply reflects areas of concentration changing; the open water available to capture heat will remain the same or increase, right up until the refreeze starts.  That there *is* drift carries its own peril; ekman pumping will bring heat to the ice even if the albedo increases. Hope for high, thick clouds, over as wide a region as possible....

Good analysis.  8)

I think there is one more risk related to the 2012 and 2013 Spring cracking events in the CAB.

With sufficient loss of MYI, we see that the ice is now highly vulnerable to strong winds during the cold season. Couple those with the trans-Arctic drift current, and there is a real possibility that a big portion of the MYI remaining after the Summer minimum could be swept into the Atlantic over the Winter.

We wake up in Spring 2014 with >90% FYI. Then it all melts out by end of Summer 2014.  Could also happen in 2015, 16, or later. :o

Not saying that this will happen, but it is one possible trajectory for the forced disappearance of the perennial ice pack.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 08, 2013, 08:28:43 AM
daily update 20130707.

Extent : -96k (+340k vs 2012)
Area: -88k5 (+423k vs 2012)

Biggest decline in Kara, Laptev follows as well. Also the -26k of Chukchi  is remarkable. Hudson recovered a bit from yesterdays increase. CAA has another big increase. Beaufort has big area increase but manages to show an extent decline.

Graphics are in the top post.

The details:

Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                  -14.7                    -2.9                   -18.4
               Kara Sea             Barents Sea           Greenland Sea
                   -9.3                    -0.2                   -17.2
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                    3.3                     0.0                   -35.2
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                    3.9                     3.4                    -9.3
             Bering Sea          Sea of Okhotsk            Total Extent
                   -1.1                     1.7                   -96.0

Area:
           Arctic Basin       East Siberian Sea              Laptev Sea
                    3.0                    -1.1                   -14.2
               Kara Sea             Barents Sea           Greenland Sea
                  -32.0                     0.0                   -14.6
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                    9.7                     0.0                   -26.0
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   19.5                    -5.6                   -26.6
             Bering Sea          Sea of Okhotsk              Total Area
                   -0.7                     0.2                   -88.5
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 08, 2013, 08:42:14 AM
Regions of the day are the Chukchi and East Siberian Seas. Chukchi has shown a steady decline at a rate slightly below 2012. The ESS should start declining about now if it wants to copy 2012.

(log in to see attached image)

 
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 08, 2013, 09:22:59 AM
Comparison Arctic Roos Norsex Area with AMSR2 3.125 Area. Arctic Roos use a 25km grid:

http://arctic-roos.org/observations/satellite-data/sea-ice/ice-area-and-extent-in-arctic (http://arctic-roos.org/observations/satellite-data/sea-ice/ice-area-and-extent-in-arctic)

All years except  2012 and 2013 were removed.

(log in to see attachment)

Title: Re: Home brew AMSR2 extent & area calculation
Post by: ChrisReynolds on July 08, 2013, 06:33:17 PM
Wipneus,

A technical question not directly related to this thread. I've asked at Tamino's but got no response from the commenters there.

I have a pattern in sea level pressure (SLP) which is the average SLP for summer 2007 to 2012. I want to make a numerical index of the presence of this pattern in daily/monthly/seasonal SLP data from NCEP/NCAR.

In an initial play around with monthly and JJA averages I have produced the sort of behaviour I have been expecting; from 2007 the JJA averages and almost all monthly averages show a strong index, years before 2007 show a weak index. But I've just used Excel's Correl function (Pearson correlation) applied to 2d matrices of SLP across the northern hemisphere north of 30degN.

I'm not sure correlation is really the right tool for the job. I've been digging around and EOFs seemed hopeful, but they seemed to be mainly used for finding patterns, not deducing the strength of a standard pattern in data.

In producing the AO Index the NOAA use a 'loading pattern' and project observed SLP onto it so as to get a numerical index of the strength of the AO pattern. That's the sort of thing I will be doing, and if I draw a blank I'll email them to ask how they 'project'.

Have you ever done anything like this? Can you point me in the right direction?
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 08, 2013, 07:58:04 PM
I have not done anything like this, but don't mind to think along.


I have a pattern in sea level pressure (SLP) which is the average SLP for summer 2007 to 2012. I want to make a numerical index of the presence of this pattern in daily/monthly/seasonal SLP data from NCEP/NCAR.


Unfortunately I am lost here already.

By the pattern you mean you have something like a 2D grid, with every on every grid cell the average of pressures at that point during the summers 2007-2012. Correct?

Now you want to do something with "the presence of this pattern" in an actual pressure pattern. Even if I knew what that was, is it not the wrong way around looking for the presence of an average (which is a summation of a number of actual patterns) in an individual one?

Quote
I'm not sure correlation is really the right tool for the job. I've been digging around and EOFs seemed hopeful, but they seemed to be mainly used for finding patterns, not deducing the strength of a standard pattern in data.

EOFs like in PCA are used to establish the MEI index, and indicator for the El Nino strength. IIRC MEI uses a dozen or so inputs, not a full grid though. 

Quote

In producing the AO Index the NOAA use a 'loading pattern' and project observed SLP onto it so as to get a numerical index of the strength of the AO pattern. That's the sort of thing I will be doing, and if I draw a blank I'll email them to ask how they 'project'.

I thought AO was just a simple pressure difference. Perhaps not, it could mean they are doing something like the MEI.

Not too helpful,  I am afraid.

Title: Re: Home brew AMSR2 extent & area calculation
Post by: ChrisReynolds on July 08, 2013, 08:28:30 PM
Thanks anyway, just to fill in some gaps.

Here is the average pressure field for JJA 2007 to 2012.
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Ffarm3.staticflickr.com%2F2865%2F9191361681_178a697c06_o.png&hash=672e4ca6eeb0f889e07a2fa4eab56bbd)

The question is: To what degree is this field present in the years since 1980 (IIRC when the data I have access to starts from). I know that it's not visibly present pre 2007, but is strongly present since then. On a monthly basis just by correlating 2d matrices of sea level pressure (the numeric version of NCEP/NCAR pressure anomaly plots) it's present in all June July Aug since 2007 apart from July 2010 and June 2013.

The NAO is the difference between pressure over the Azores and Iceland (IIRC it's normalised to the SD). But the AO index is constructed by projecting the daily (00Z) 1000mb height anomalies poleward of 20°N onto the loading pattern of the AO.
http://www.cpc.ncep.noaa.gov/products/precip/CWlink/daily_ao_index/ao.shtml (http://www.cpc.ncep.noaa.gov/products/precip/CWlink/daily_ao_index/ao.shtml)

The reason I've suddenly veered onto this is that the pattern shown in the image above plays a strong role in the post 2007 sea ice behaviour, Overland et al 2012 find it generates a dipole: low pressure along Siberia and high over the pack to Greenland. The failure of this pattern so far this year means this is a perfect opportunity to dig around to try to find out the cause. It's an opportunity I just can't pass up.

To do that I need a timeseries (down to daily) from which to begin to establish correlations.

I'm going to email the people who do the AO index.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: BornFromTheVoid on July 08, 2013, 08:57:18 PM
Chris,

I worked on something similar, but more more simplified, thing to yourself for my undergraduate dissertation last year.
Related to the dipole, I created an index around the Fram Strait using NCEP/NCAR reanalysis data SLP for two pairs of points, seen in the image below.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FpPXS6Sz.gif&hash=3f86d54c88aae56462cc6e9ccc5a7369)

I figured that to enhance sea ice export, you need the air flowing towards Fram, and from the strait itself toward the Greenland sea, helping to reduce summer sea ice extent (my understanding has come along some way since then!).

Anyway, the index worked off the monthly data, and whereby if the pressure on the western points are higher (lower) than the east, you'd get enhanced (subdued) summer export and reduced (increased) extent. So basically a pressure difference index.
Here's what I got for the Summer timeseries.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FDJ9lzCk.gif&hash=7e35117142405060a71bc7ca2e1c1745)

The 2007-2012 period had the highest 6 year mean for the index for June also, with this year being the first below average June since 2005.

I suspect it would be closely related to the pressure pattern your working on.

EDIT: Also, I think you'd find it hard to differentiate your pattern from the NAO loading pattern http://www.cpc.ncep.noaa.gov/products/precip/CWlink/pna/nao_loading.html (http://www.cpc.ncep.noaa.gov/products/precip/CWlink/pna/nao_loading.html)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Neven on July 08, 2013, 09:49:47 PM
Chris, when I have time later this week I want to download weekly SLP maps from the daily composite page, from May to September, and put those on a special page on the ASIG (a bit like SIC map comparison page). Depending on how much space I have, I'm planning to do all the years since 2005 (or at least since 2007).

Maybe that'll be useful to you. It will be for me, but I'm more into the weather forecast side of things. Unfortunately, I lack the skills to quantify.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: anonymous on July 08, 2013, 10:09:56 PM
Chris, you can access most GFS data (wind, pressure, temps) between Mar 2004 and Jan 2013 with an url like this:

Code: [Select]
http://nomads.ncdc.noaa.gov/dods/NCEP_GFS_ANALYSIS/analysis_complete.ascii?pressfc[30:1:33][180][0]
The scheme after the question marks is param[time][latitude][longitude]. Example gives you pressure (pa) for four points in time with a distance of 6 hours for the North pole. Excel should be able to reformat the result to your needs, GSpreadsheet can.

Code: [Select]
pressfc, [4][1][1]
[0][0], 100517.0

[1][0], 100512.0

[2][0], 100399.0

[3][0], 100027.0


time, [4]
731649.5, 731649.75, 731650.0, 731650.25
lat, [1]
90.0
lon, [1]
0.0

Description (http://nomads.ncdc.noaa.gov/dods/NCEP_GFS_ANALYSIS/analysis_complete). The nomad servers just migrated to new hardware, expect some hiccups.

Wipneus, feel free to move this to dev.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: ChrisReynolds on July 08, 2013, 10:13:25 PM
Born from the Void,

Fascinating, a good approach. What I'm trying to do is to capture the wider pattern, so I've already ditched the idea of a weighting type approach.

Neven,

Go ahead, this is really just the continuation of what started with my original Summer Daze post back in 2011.
http://dosbat.blogspot.co.uk/2011/09/summer-daze.html (http://dosbat.blogspot.co.uk/2011/09/summer-daze.html)


Both,

For what it's worth, using the Excel Correl function for north of 30degN I get the following.

2000   -0.158
2001   -0.218
2002   -0.418
2003   -0.185
2004   +0.169
2005   +0.531
2006   -0.539
2007   +0.845
2008   +0.845
2009   +0.833
2010   +0.439
2011   +0.893
2012   +0.631

If I 'window' in on the immediate region of the pattern (around 3000km away from Greenland) I should get even greater correlations post 2007. It seems to work, but that's no guarantee it's the best method, or even a sound method. I've been messing around with artificial datasets, and have read a couple of primers on PCAs, which are the simpler cousins of EOFs. If I can't get to grips with a better technique I may just use correlation in the interim until I can do better.

If only I weren't such a math dunce, what I've read on PCAs is very daunting.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: ChrisReynolds on July 08, 2013, 10:17:16 PM
Arcticio,

I've been using the text download link on the NCEP/NCAR pages I normally access. But discovered last night that the numbers change each time I access!

Anyway all I'm doing is getting a feel for the problem at present. I can get the base data at daily resolution here:
http://www.esrl.noaa.gov/psd/data/gridded/tables/surface.html (http://www.esrl.noaa.gov/psd/data/gridded/tables/surface.html)

If people want to discuss this further I can do a new thread to stop spamming Wipneus's thread with off topic stuff. But not tonight.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: crandles on July 08, 2013, 10:18:01 PM
Chris, that pattern looks quite easy to describe - a high centred on mid Greenland.

You could calculate the ring around centre of Greenland that has lowest pressure deepest blue and measure pressure difference between central Greenland and that ring.

That probably isn't all that you want. It shouldn't be hard to create a measure being the proportion of points, which compared to surrounding 8? points, obey the rule that the further from the centre, the lower the pressure should be.

I don't know if having two measures like that is a major problem compared to having 1 index or whether it would be good to have a 'how-well-placed' measure and a strength measure. You may well be better with expert advice rather than listening to me.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: anonymous on July 08, 2013, 11:57:29 PM
Chris, never made it through that link jungle. But wonder why you use pressure as proxy for wind as proxy for drift?
Title: Re: Home brew AMSR2 extent & area calculation
Post by: ChrisReynolds on July 09, 2013, 07:40:20 AM
Arcticio,

I'm not using the post 2007 pattern for anything, it just represents a post 2007 change in NH circulation and needs investigating.

Crandles,

I have pondered doing a sum of differences at specific points/regions, e.g. Siberian coastal region, US Eastern Seaboard to UK. But I'd rather use the whole pattern.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 09, 2013, 08:24:40 AM
Update 20130708.

Extent: -143k6 (+258k vs 2012)
Area: -146k5 (+329k vs 2012)

All regions are now going down without extreme fast runners. The whole Siberian side shows solid decline. The CAA that did show increases for the last days, has slowly returned to melting.

The details:

Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                  -12.6                   -11.1                   -18.8
               Kara Sea             Barents Sea           Greenland Sea
                  -19.2                    -0.8                    -9.0
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                  -27.7                     0.0                   -19.2
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   -4.2                   -11.9                    -6.6
             Bering Sea          Sea of Okhotsk            Total Extent
                   -0.4                    -1.9                  -143.6

Area:
           Arctic Basin       East Siberian Sea              Laptev Sea
                    0.5                   -20.7                   -20.7
               Kara Sea             Barents Sea           Greenland Sea
                  -20.4                    -0.5                   -21.8
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                  -23.7                     0.0                     3.5
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                  -28.9                    -4.8                    -7.9
             Bering Sea          Sea of Okhotsk              Total Area
                   -0.2                    -0.9                  -146.5
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 09, 2013, 08:42:23 AM
To days image, the Canadian Archipelago. The break offs in the Nares Strait are clearly on the move: blue in the front, red in the wake. Cracks don't show.

(log in to see attached image)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Artful Dodger on July 09, 2013, 10:52:55 AM
To days image, the Canadian Archipelago. The break offs in the Nares Strait are clearly on the move: blue in the front, red in the wake.
Hi Wipneus,

This is awesome stuff!  8)

Any chance of creating a "2-week delta" map of sea ice loss over the whole Arctic?

EDIT: BAH! I see it's already done!! Wonderful, fellows  8)

I think that'd be an awesome contribution to Neven's bi-weekly sea ice updates over at the 'blog  ;)

And it would really put the cumulative effect of daily losses into perspective!

Thanks again for your excellent work with this project
Title: Re: Home brew AMSR2 extent & area calculation
Post by: danp on July 10, 2013, 02:48:27 AM
To days image, the Canadian Archipelago. The break offs in the Nares Strait are clearly on the move: blue in the front, red in the wake. Cracks don't show.

(log in to see attached image)

As some visible light confirmation of the melt pattern the microwave maps are showing, here's the last 5 days for one of the northernmost red-marked melt spots, between Melville & Bathurst Islands if I've got my geography correct.  The images are extracted from MODIS Terra swaths, ch. 1+4+3, 500m resolution.  You can see both melting in place and small floes breaking off along the rotten edge of the hole.

You can also see how deep blue, cracked, and ready-to-melt the ice elsewhere in the vicinity has looked for quite a while now.  But the visible light also agrees with the microwave-derived maps that no significant melt ponds or holes have opened up.   It will be exciting as more of it starts to go!

(https://dl.dropboxusercontent.com/s/kesrs6bpyvs6u0r/anim143caa.gif)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 10, 2013, 07:29:42 AM
Thanks Dan, that is fun. Here is the amsr2 3.125km image of that spot. I had to rotate 45deg to get the same orientation, causing a slight blur (North is to the right in the image now).

 
Title: Re: Home brew AMSR2 extent & area calculation
Post by: danp on July 10, 2013, 08:55:26 AM
Thanks Dan, that is fun. Here is the amsr2 3.125km image of that spot. I had to rotate 45deg to get the same orientation, causing a slight blur (North is to the right in the image now).

 

Thanks for the close-up Wipneus - very helpful.  I should probably figure out how to get my land mask working properly to facilitate alignment like this.

Looking closer I realize a couple things:
1. AMSR2 is doing really well at picking out the open water boundaries and the minute changes around those edges.

2. I was overly focused on the concentration changes, rather than the actual concentrations marked.  On this AMSR2 has clearly been confused into categorizing the solid but blue ice as <100% concentration: note the large greyish-labelled areas that are still clearly frozen in visible light. 

In addition I misread one of those red patches as being a recent opening of the hole, but in fact both of the patches in the upper right of the closeup are still solid blue ice as of my latest imagery from the 9th (though my processing may be running slightly behind as I'm always waiting on downloads).  Still I suspect that in the blue ice areas the microwave may be showing some combination of noise near its discrimination threshold, and real thinning in the ice which does not yet represent opening water.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 10, 2013, 09:00:48 AM
20 minutes later than we are used to, the data from U-Hamburg came in.

Extent: -127k3 (+218k vs 2012)
Area: -126k6 (+293k  vs 2012)

All Siberian regions from Kara to Chukchi are contributing to the decline. Beaufort seems to start as well. The ice in the Greenland sea continues to disappear.
Although Hudson and Baffin still have some ice, they contribute less than a third of the net total decline.

The details:

Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   -3.9                    -9.7                   -11.5
               Kara Sea             Barents Sea           Greenland Sea
                  -18.8                     0.4                   -22.0
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -6.8                     0.0                   -32.8
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   -3.2                   -10.0                    -8.1
             Bering Sea          Sea of Okhotsk            Total Extent
                   -0.2                    -0.7                  -127.3

Area:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   16.6                   -36.6                   -15.7
               Kara Sea             Barents Sea           Greenland Sea
                   -5.5                     0.1                   -15.2
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -7.9                     0.0                    -5.1
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                  -22.5                   -18.7                   -15.8
             Bering Sea          Sea of Okhotsk              Total Area
                   -0.1                    -0.2                  -126.6

 
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 10, 2013, 09:27:22 AM
Beaufort is region of the day. Polynya are more extended today as not before this season.

(log in to see the attached image)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 10, 2013, 09:54:14 AM

2. I was overly focused on the concentration changes, rather than the actual concentrations marked.  On this AMSR2 has clearly been confused into categorizing the solid but blue ice as <100% concentration: note the large greyish-labelled areas that are still clearly frozen in visible light. 


Just to make sure, it is me that marks pixels with concentration going from over 15% to below 15% red, and from below to over 15% blue. Pixels that stay below 15% or above 15% are grey (black - white).

Be aware as well, that the sea ice concentration algorithms are optimized for sea and ice. Pixels near coasts will have some contamination introduced from the microwave emissions from land surface. Pixels that are surrounded by "land pixels" will be affected more. In most cases this translates into more ice than reality. I use some logic to remove such ice, this works quite well over the whole Arctic but maybe not in every little corner.

Attached, a "raw" image of that area.

Title: Re: Home brew AMSR2 extent & area calculation
Post by: danp on July 10, 2013, 11:46:10 AM

Be aware as well, that the sea ice concentration algorithms are optimized for sea and ice. Pixels near coasts will have some contamination introduced from the microwave emissions from land surface. Pixels that are surrounded by "land pixels" will be affected more. In most cases this translates into more ice than reality. I use some logic to remove such ice, this works quite well over the whole Arctic but maybe not in every little corner.

Attached, a "raw" image of that area.
This is not the issue I'm noticing though.  In your raw image, there are already lots of deep grey areas that the microwave sensor algorithm believes are between 15-100% concentration.  But the visible pictures between clouds just show expanses of cracked but unbroken deep blue ice, which I'm suggesting is fooling the sensors.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Peter Ellis on July 10, 2013, 12:17:14 PM
Yup, some of the ice seems to be thin enough (or wet enough on top, or both) that the sensor sees straight through it.  It'll be gone soon though.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Neven on July 10, 2013, 12:32:10 PM
Wipneus, this has become my favourite corner of the Internet.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: BornFromTheVoid on July 10, 2013, 12:44:50 PM
Wipneus,

Would it be possible to take the MODIS Arctic mosaic, then overlay your pixel change images with enough transparency to see both the changed pixels colour and the visible ice below?
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 11, 2013, 08:24:37 AM
Update for 20130710.

Extent: -99k7 (+361k vs 2012)
Area: -136k6 (+332k vs 2012)

This decline is strong as most of the decline is now within the Arctic itself: the peripherals Hudson, Baffin and Greenland have, taken together, almost no change. ESS and Beaufort really seem to  take off now.


The details (in 1000 km2):

Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   -9.9                   -18.1                   -14.0
               Kara Sea             Barents Sea           Greenland Sea
                  -14.1                    -0.5                     7.2
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -2.2                     0.0                    -6.2
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                  -15.3                   -14.7                   -14.1
             Bering Sea          Sea of Okhotsk            Total Extent
                    0.3                     1.8                   -99.7

Area:
           Arctic Basin       East Siberian Sea              Laptev Sea
                  -24.0                   -46.5                   -20.3
               Kara Sea             Barents Sea           Greenland Sea
                   -4.8                    -0.5                     8.8
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -3.0                     0.0                    -4.5
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   -4.3                   -27.0                   -12.7
             Bering Sea          Sea of Okhotsk              Total Area
                    0.2                     2.0                  -136.6
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Artful Dodger on July 11, 2013, 08:36:03 AM
Hi Wipneus,

It looks like sea ice transport has restarted in the Greenland sea. Dipole, anyone?
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 11, 2013, 08:43:23 AM
Regions of the day are Kara and Barentsz. Barentsz is now officially and completely ice free.
Kara, at this rate, will be in around 4 weeks. The decline of the CAB is almost all captured in this image.

(log in to see attached image)

Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 11, 2013, 08:57:40 AM
Lodger:

Most of the decline in the CAA is in the western corner (between Banks and Victoria islands and the continent). See yesterday's image of the day.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Artful Dodger on July 11, 2013, 09:56:08 AM
Lodger:

Most of the decline in the CAA is in the western corner (between Banks and Victoria islands and the continent). See yesterday's image of the day.
Hi Wipneus,

Wonderful charts. But with both Area and Extent up in the Greenland sea, and with high SSTs in the region, we can say with confidence that that sea ice arrived from the Central Basin.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 11, 2013, 10:50:05 AM
Ah, yes. I misread Greenland for Canada some how.

The Greenland sea ice is starting to move again (still melting though). If this continues a couple of days, I will dig up my animation skills again.

Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 12, 2013, 08:25:44 AM
Update 20130711.

Extent:-87k3  (+449k vs 2012)
Area:-163k2  (+300k vs 2012)

The "torch" seems to be on in the Chukchi sea. Strong declines on the Siberian side, less in Beaufort and CAA. Area is outpacing extent esp. in CAB, ESS and CAA.


The details (in 1000 km2):

Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   -4.6                   -12.1                   -16.9
               Kara Sea             Barents Sea           Greenland Sea
                  -16.8                     0.3                     9.7
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                  -14.1                     0.0                    -2.0
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   -2.8                    -4.2                   -22.5
             Bering Sea          Sea of Okhotsk            Total Extent
                    0.5                    -1.9                   -87.3

Area:
           Arctic Basin       East Siberian Sea              Laptev Sea
                  -65.1                   -27.1                   -17.3
               Kara Sea             Barents Sea           Greenland Sea
                  -18.8                     0.2                    -2.3
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -9.1                     0.0                     1.6
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                  -10.5                     3.2                   -16.5
             Bering Sea          Sea of Okhotsk              Total Area
                    0.5                    -2.0                  -163.2
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 12, 2013, 08:46:06 AM
Region of the day is the "torch" Chukchi sea. I posted an image of the Nares break-up in the Nares thread.

(log in to see attached image)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Neven on July 12, 2013, 08:56:41 AM
There'll be more of that in days to come. The northern Chukchi already has melt holes in it.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: jdallen on July 12, 2013, 09:25:49 AM
There'll be more of that in days to come. The northern Chukchi already has melt holes in it.

I'm anticipating a "tip over" event, where thin ice within some areas of extent vanishes in a very short time (less than a week) over a large area, leaving isolated floes of MYI.

Portions of the Beaufort  and CAA are my favorite candidates for this.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 13, 2013, 08:19:31 AM
Update 20130712.

Extent:  -151k6 (+391k vs 2012)
Area:  -72k2 (+384k vs 2012)

I have to be brief, train to catch.

If not for Hudson, Baffin and Greenland resuming the melt, the situation is much the same as yesterday. Declines on the Siberian side, much of it in Chukchi. Slow Beaufort and CAA.


The details in 1000 km2:

Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                  -12.2                   -10.1                    -4.3
               Kara Sea             Barents Sea           Greenland Sea
                  -19.1                    -1.2                   -21.2
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                  -30.5                     0.0                   -21.5
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   -5.5                    -0.2                   -24.9
             Bering Sea          Sea of Okhotsk            Total Extent
                   -0.6                    -0.2                  -151.6

Area:
           Arctic Basin       East Siberian Sea              Laptev Sea
                  -58.2                    22.6                    -6.4
               Kara Sea             Barents Sea           Greenland Sea
                  -16.3                    -1.0                   -21.1
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                  -17.1                     0.0                   -16.3
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   30.3                    23.8                   -11.6
             Bering Sea          Sea of Okhotsk              Total Area
                   -0.5                    -0.3                   -72.2
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 13, 2013, 08:26:12 AM
Image of the day, Greenland Sea, shows the large chunck of fast ice breaking of NE greenland.

(log in to see attached image)

Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 14, 2013, 08:25:32 AM
Update 20130713:

Extent: -74k5 (+340k vs 2012)
Area: -113k7 (+239k vs 2012)

For extent it is a relatively quit day. ESS takes lead, followed by Chukchi. Changes for area are in comparison bigger in the CAB and Beaufort. CAA shows small increases for both extent and area.

The details (in 1000 km2):


Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   -3.0                   -18.3                    -2.5
               Kara Sea             Barents Sea           Greenland Sea
                  -11.0                    -0.7                     0.1
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -6.9                     0.0                   -17.3
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                    3.2                    -3.1                   -13.1
             Bering Sea          Sea of Okhotsk            Total Extent
                   -0.1                    -1.9                   -74.5

Area:
           Arctic Basin       East Siberian Sea              Laptev Sea
                  -58.7                     4.9                   -11.8
               Kara Sea             Barents Sea           Greenland Sea
                   -6.9                    -0.4                    17.9
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -2.9                     0.0                   -27.3
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                    9.5                   -24.3                   -12.2
             Bering Sea          Sea of Okhotsk              Total Area
                    0.0                    -1.6                  -113.7
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 14, 2013, 08:35:36 AM
The action is in the Chukchi and East Siberian Sea's, movement and melting as seen in to days image.

(log in to see attached image)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 14, 2013, 08:51:45 AM
BTW, new data from Uni Hamburg is comes in normally at about 6:15 UTC. An update is done about 14 hours later, normally without any data actually changing: I only see the file modification time differ.

The update of 20130712 is the first time I noticed a small downward revision.

Extent: -154k3 (from 151k6)
Area: -78k2 (from -72k2)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 15, 2013, 08:19:06 AM
Update 20130714.

Extent: -108k0  (+263k vs 2012)
Area: -92k8 (+271k vs 2012)

Most of the net decline is in Chukchi, ESS and Kara. Crumbs for CAB, CAA, Beaufort and Laptev.

Updated graphics are in the top post.

The details (in 1000 km2):

Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   -5.2                   -23.2                    -8.6
               Kara Sea             Barents Sea           Greenland Sea
                  -23.0                     0.8                    -4.6
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                  -20.5                     0.0                    12.3
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                  -10.6                    -6.2                   -18.6
             Bering Sea          Sea of Okhotsk            Total Extent
                    0.4                    -0.7                  -108.0

Area:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   25.0                   -21.0                   -14.4
               Kara Sea             Barents Sea           Greenland Sea
                  -18.2                     0.7                    -6.8
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                  -15.6                     0.0                    18.0
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                  -41.6                     1.4                   -19.8
             Bering Sea          Sea of Okhotsk              Total Area
                    0.4                    -1.2                   -92.8

Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 15, 2013, 08:34:52 AM
Region of the day is Laptev, slow in the net numbers. The image shows there is movement of the ice, causing increases and decreases in places.

(log in to see attached image)

Title: Re: Home brew AMSR2 extent & area calculation
Post by: Bob Wallace on July 15, 2013, 10:00:39 AM
Thanks.  You've turned  this into a really great horse race for me.

I find it very interesting that 2013 is ahead of 2012 in both extent and area for the CAB.  Add in the CA and GS and 2013 is ahead in terms of last year's "didn't fully melt" regions.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: LarsBoelen on July 15, 2013, 11:37:33 PM
Wipneus, I got totally inspired by all your graphical work, I'd like to add my 2 cents with a movie of al the frames of AMSR2 (I cleaned the frames up til july)

http://stormglas.wordpress.com/2013/07/15/daily-amsr2-update-movie-of-northpole-melting-in-2013/ (http://stormglas.wordpress.com/2013/07/15/daily-amsr2-update-movie-of-northpole-melting-in-2013/)

Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 16, 2013, 08:21:56 AM
Update 20130715.

Extent: -124k9( +225k vs 2012)
Area: -32k7 (+316k vs 2012)

Large extent decline continues in Chukchi, Laptev and Kara, followed by ESS and CAA. The CAB and Beaufort are still "modest".
Area follows mostly the pattern of extent, except for a big increase in the CAB and a more modest one in Chukchi.

The details in 1000 km2 :

Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   -4.7                   -10.1                   -22.7
               Kara Sea             Barents Sea           Greenland Sea
                  -20.4                    -0.2                   -11.2
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -4.9                     0.1                    -2.9
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   -9.2                    -5.7                   -32.0
             Bering Sea          Sea of Okhotsk            Total Extent
                    0.2                    -1.2                  -124.9

Area:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   44.2                    -8.5                   -28.8
               Kara Sea             Barents Sea           Greenland Sea
                  -14.3                    -0.2                   -14.8
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -4.4                     0.1                   -16.1
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   -1.5                     0.1                    12.4
             Bering Sea          Sea of Okhotsk              Total Area
                    0.2                    -1.1                   -32.7
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 16, 2013, 08:34:14 AM
Region of today is Kara. The ice flotilla behind Nova Zemlya is nearly gone. The fast Ice behind Severnaya Zemlya looks much tougher.

(log in to see attached image)
 
Title: Re: Home brew AMSR2 extent & area calculation
Post by: werther on July 16, 2013, 09:04:29 AM
Thanks, Wipneus,

Didn't you post the ice thickness anomaly compared to '12 in nice colours in April? That pic illustrated that 'fast ice' against Severnaya zemlya to be tough. It might be a part of Kara Sea ice holding out long enough to contribute 50-100K to remaining minimum SIE.

As for the CAB area increase; in line with my comment on the 'short term' thread, I think it may indicate a stage near the start of complete fading out of large parts of the Chukchi-/ESAS- and Laptev sectors.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 16, 2013, 09:20:16 AM
Werther,

PIOMAS ice thickness map for May 2013 (latest we have):
(https://sites.google.com/site/arctischepinguin/home/piomas/grf/pg_5_2013.png)

And 2012-2013 differences:

(https://sites.google.com/site/arctischepinguin/home/piomas/grf/thickness_chg_may13.png)

The thicker ice seems to be (according to PIOMAS) on the Laptev side of Severnaya Zemlya.

And thanks for reporting what you see on MODIS. It helps interpretating what the different products report as concentration or the derived "area".
Title: Re: Home brew AMSR2 extent & area calculation
Post by: werther on July 16, 2013, 10:43:32 AM
Again, thanks for re-issuing that map, Wipneus.

I thought there was an earlier map for April, but I guess it was that one.

Illustrating the different niche-behaviour of the ice formation-growth-melt process in all regions, this had me confusing. Your May map shows the anomalous thickness on the Laptev side, where it is almost depleted now. It does show the anomaly on the South side of the Kara Sea, where indeed there’s still (melting) ice in the Baydaratskaya Bay.

The ‘fast ice’ to the West of Severnaya Zemlya was never a “shelve” like this last year. There was a band of fast ice close to the coast, the rest never even froze completely that season and was almost depleted even as early as day 150.
The difference has been the predominantly South-Eastern winds over the Kara January-April and the associated cold on the continental side of the Arctic Ocean.

I think it shows again never to rely on information from one source. This 100K ice is completely different, structure-wise, than last year. Still, it is FYI, and having another good look at it this morning, I think I suggested too early that part of it might survive…
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 17, 2013, 08:25:20 AM
Update 20130716.

Extent: -94k2 (+198k2 vs 2012)
Area: -38.7 (+239k4 vs 2012)

Kara has the most aggressive melt, followed by Laptev and Chukchi. Beaufort, the region that is lagging most to 2012, is showing a slow but steady increase in melt rates (-3, -6, -9) over the last few days.

Updated graphs can be seen in the top-post.

The details (in 1000 km2)

Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   -4.7                    -2.6                   -12.7
               Kara Sea             Barents Sea           Greenland Sea
                  -31.9                     0.2                    11.7
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                  -11.6                    -0.1                   -16.4
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   -3.1                    -9.1                   -13.8
             Bering Sea          Sea of Okhotsk            Total Extent
                    0.2                    -0.5                   -94.2

Area:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   10.8                     2.6                   -14.0
               Kara Sea             Barents Sea           Greenland Sea
                  -14.7                     0.2                    13.5
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                  -14.7                    -0.1                    -0.9
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   -1.5                    -9.1                   -10.1
             Bering Sea          Sea of Okhotsk              Total Area
                    0.1                    -0.8                   -38.7
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 17, 2013, 08:43:29 AM
Region of the day is the Canadian Archipelago. Various darkening caused can be seen that are quite stable indicate probable melting. The NW passage via the Parry Channel and McClure Strait does not look like it is opening soon.

Movement in the Nares strait can be seen as well.

(log in to see attached image)

Title: Re: Home brew AMSR2 extent & area calculation
Post by: LarsBoelen on July 17, 2013, 11:22:24 PM
Wipneus, being only a second year MeltSeasonWatcher I wonder if you have any insights in the huge differences between IJIS and your calculations. Ijis has basically stalled the past few days, but if you look at the "movie" of the meltseason (http://stormglas.wordpress.com/2013/07/15/daily-amsr2-update-movie-of-northpole-melting-in-2013/ (http://stormglas.wordpress.com/2013/07/15/daily-amsr2-update-movie-of-northpole-melting-in-2013/)) there does not appear to be any slowdown.

It looks like transport through Fram strait might restart, but does this cause an almost immidiate Increase in extend of almost 100K?
Title: Re: Home brew AMSR2 extent & area calculation
Post by: werther on July 18, 2013, 12:30:57 AM
At the risk of talking before my turn...
Yes, it does, Lars...
You mention the Fram, I think more of all fringe regions. The ice is extremely mobile now. Spreading while cracking up and filling the voids with rubble and/or melting foam.
In my opinion, the grid on which the automated algorithm is scaled is too coarse to get this.
The melt plot is not the same in each region.
There are parts where the clear, ice covered, structureless swaths of rounded floes now have transited into seemingly endless low-albedoplates with myriads of holes.
Elsewhere (FI the Chukchi), the ice is fading into foam like end July last year.

Through the last few years most graphs/sensors/numbers were ''on-off" this time of the year on the rapidly melting fringes. I think this year is extreme. Weather, DMI temps...I don't think they are as important as they used to be.
It's the structure... I never suggested temporary ice-free this season. But a record, yes. I think some regions will go "in a flash".
It's just a matter of the right pinch-hitter.

Watch out for ECMWF next week. Circlin' low, strong winds.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 18, 2013, 08:29:25 AM
Update 20130717.

Extent:  -108k0 (+123k vs 2012)
Area:  -66k2 ( +260k vs 2012)

No special fast runners today. Chukchi has not moved at all, otherwise all active regions continue to decline.
Curiously that area is now quite slow for a couple of days. It was the same like that last year, so the gap with 2012 is not widening.

Have a look at the updated graphs in the top post.

The details (in 1000 km2):
Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   -5.3                    -8.6                   -14.5
               Kara Sea             Barents Sea           Greenland Sea
                  -17.3                     0.3                   -14.8
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                  -17.0                     0.1                   -10.4
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                  -11.2                    -7.5                     0.6
             Bering Sea          Sea of Okhotsk            Total Extent
                    0.0                    -2.4                  -108.0

Area:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   25.3                   -17.8                   -12.3
               Kara Sea             Barents Sea           Greenland Sea
                  -22.2                     0.1                   -20.0
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                  -12.4                     0.0                    -8.0
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                    2.7                    -2.3                     1.9
             Bering Sea          Sea of Okhotsk              Total Area
                    0.0                    -1.3                   -66.2
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 18, 2013, 08:42:20 AM
Region of the day is Beaufort. The stronghold that has managed to keep the melting (s)low. The polynya in the middle of the pack that I showed a week ago has also closed again.

(log in to see attached image)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 18, 2013, 09:33:15 AM
Wipneus, being only a second year MeltSeasonWatcher I wonder if you have any insights in the huge differences between IJIS and your calculations. Ijis has basically stalled the past few days

I would ignore fluctuations lasting "few days" especially when only one of the timelines is showing them. The declining of NSIDC, IJIS and my AMSR2 are nearly the same, and I expect IJIS either to revise or come with a rather big jump soon.

And I would like to know why exactly my AMSR2  extent is currently about 800k below the others. It could be caused by the source data, it could be in the nitty gritty of the calculation details.

In contrary to my first impression, it probably not the resolution difference. Resolution has been in the past overstated as cause for differences in the various extent/area data.

I will tell you more as soon as find out.

And yes, changes in wind patterns can cause distinctive regional changes. They more or less cancel out on the total.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Rob Dekker on July 18, 2013, 11:10:48 AM
Wipneus,
Awesome work you present here ! Thank you !

You may have explained this before, but considering the interesting high extent/area ratio that your calculations show, could you give again a precise definition of how you calculate extent and how you calculate area on your grid ?
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Rob Dekker on July 18, 2013, 11:20:02 AM
I'm sorry. I meant the high area/extent ratio, and specifically the high area compared to Cryosphere Today.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 18, 2013, 12:10:43 PM
You may have explained this before, but considering the interesting high extent/area ratio that your calculations show, could you give again a precise definition of how you calculate extent and how you calculate area on your grid ?

Always happy to explain :-).

But first, I outlined the calculation in the top post of this discussion.
Further I went into the CT-nigma yesterday, see this page:
https://forum.arctic-sea-ice.net/index.php/topic,418.50.html (https://forum.arctic-sea-ice.net/index.php/topic,418.50.html)

Let me try to be exactly precise about extent and area.

There is some pre-processing to handle 1) pole hole; 2) phantom ice; 3) "coastal" pixels; 4) lakes are excluded; and 5) a mask is used to limit the calculations to the well known(?) CT regions.

Definitions:

The extent is calculated as the sum of areas of all grid cells that have concentration >15%
 
The area is calculated as the sum of areas of all grid cells that have concentration >15% multiplied with the concentration of those grid cells.


Anyone can convince himself by analyzing the concentration maps in https://sites.google.com/site/apamsr2/home/pngcby32 (https://sites.google.com/site/apamsr2/home/pngcby32)

Made to please A-Team in his desire for scientific standard png files, the have ice concentration 0-100% mapped to 0-255. You will notice that the concentrations values are (on average) bigger than those in the CT maps.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Richard Rathbone on July 18, 2013, 12:12:11 PM
Differences with other methods come in the sensors and algorithms used to get concentration.  I think the CT method will report a rather lower concentration than Bremen when concentration is close to 1 (something like CT says 0.8 where Bremen says 0.95 from my eyeballing their concentration maps).
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Frivolousz21 on July 18, 2013, 12:28:57 PM
Its because you are using high resolution.

3km res will destroy 12km or 25km when it comes to picking up open water within the ice pack like the Chukchi.


This is why norsex is always so high with there totals vs the others.

And why bremen is typically lower.

this is why in 2011 bremen had a new extent record and jaxa didnt.

even though CT showed 2011 beat 2007 in area.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: dree12 on July 18, 2013, 03:16:30 PM
Curiously that area is now quite slow for a couple of days. It was the same like that last year, so the gap with 2012 is not widening.

I'm curious about how Arctic Basin area has increased (significantly) in the past 5 days! Along with extent decreases, does this mean the Arctic Basin is now more compacted?
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 18, 2013, 03:40:41 PM

I'm curious about how Arctic Basin area has increased (significantly) in the past 5 days! Along with extent decreases, does this mean the Arctic Basin is now more compacted?

    YYYYMMDD Arctic.Basin.extent Arctic.Basin.area A.B.compactness
190 20130709            4.336055          4.248204       0.9797393
191 20130710            4.326195          4.224234       0.9764317
192 20130711            4.321573          4.159117       0.9624081
193 20130712            4.310013          4.099302       0.9511112
194 20130713            4.307020          4.040629       0.9381496
195 20130714            4.301781          4.065671       0.9451134
196 20130715            4.297041          4.109884       0.9564451
197 20130716            4.292375          4.120708       0.9600065
198 20130717            4.287124          4.146012       0.9670847
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Vergent on July 18, 2013, 08:29:19 PM
When ice breaks up, it spreads out. More pixels get counted as ice. This is happening in the eastern CAB.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Ficefloe.net%2FAloftcon_Photos%2Falbums%2F2012%2F20120829-1601.jpeg&hash=6bdaaa582e64c21ffe1138c94e2c0b72)

A lot of the eastern CAB is starting to look like this(from 2012).

Verg
Title: Re: Home brew AMSR2 extent & area calculation
Post by: seaice.de on July 18, 2013, 10:14:08 PM
Great work, congratulations, Wipneus!

I am looking forward to a very exciting melt season in the next weeks...

Cheers from Bremen
LK
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Peter Ellis on July 18, 2013, 11:30:39 PM
When ice breaks up, it spreads out. More pixels get counted as ice. This is happening in the eastern CAB.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Ficefloe.net%2FAloftcon_Photos%2Falbums%2F2012%2F20120829-1601.jpeg&hash=6bdaaa582e64c21ffe1138c94e2c0b72)

A lot of the eastern CAB is starting to look like this(from 2012).

Verg

No, the eastern CAB looks nothing like this whatsoever.  Those floes are around 10 metres across - i.e. you could fit 25x25 = 625 of them in a single MODIS pixel at maximum resolution.  If you go back to MODIS imagery from that location at that date, this is what it looks like.
http://earthdata.nasa.gov/labs/worldview/?map=-555264,766976,-214528,993536&products=baselayers,MODIS_Terra_CorrectedReflectance_TrueColor, (http://earthdata.nasa.gov/labs/worldview/?map=-555264,766976,-214528,993536&products=baselayers,MODIS_Terra_CorrectedReflectance_TrueColor,)!MODIS_Aqua_CorrectedReflectance_TrueColor~overlays,polarview%3AgraticuleN,arctic_coastlines&time=2012-08-28&switch=arctic

The ice in the eastern CAB may be somewhat broken up, but it's still in floes kilometres across, not metres. Honestly, some people on these boards have literally no concept of the different scales involved in microwave imagery, MODIS imagery, and on-the-ground photographs.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: ghoti on July 19, 2013, 02:18:32 AM
I think the scale of the MODIS imagery also means the ice could be like the picture presented but we'd not see it. It is such a pity the Polar Stern doesn't have an Arctic cruise this year giving us an actual view of the ice. Doesn't look like the Healy is going anywhere far from shore this year either. We could really use a couple of Global Hawks cruising back and forth over the ice to provide better ground truth. Oh well it isn't going to happen so we're stuck guessing wildly.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Vergent on July 19, 2013, 02:34:51 AM

The ice in the eastern CAB may be somewhat broken up, but it's still in floes kilometres across, not metres. Honestly, some people on these boards have literally no concept of the different scales involved in microwave imagery, MODIS imagery, and on-the-ground photographs.

Peter

The pixel size for CT area is 15 Km(edit: best recollection). So the principle is that when ice breaks up to a scale smaller than the pixel and consequently spreads out, the area algorithm will see more ice. I chose the picture for purpose of illustration, not for scale. If you can find a picture that illustrates this with kilometer sized chunks, you are welcome to. With a 15 km pixel it makes no difference weather the break-up is at the kilometer scale or the 10 m scale, the geometry is the same.

Honestly, some people on these boards have no concept of when a difference in scale makes no difference to the validity of the argument.

Vergent

 
Title: Re: Home brew AMSR2 extent & area calculation
Post by: jdallen on July 19, 2013, 02:52:03 AM

The ice in the eastern CAB may be somewhat broken up, but it's still in floes kilometres across, not metres....

The pixel size for CT area is 15 Km. So the principle is that when ice breaks up to a scale smaller than the pixel and consequently spreads out, the area algorithm will see more ice. I chose the picture for purpose of illustration, not for scale. If you can find a picture that illustrates this with kilometer sized chunks, you are welcome to. With a 15 km pixel it makes no difference weather the break-up is at the kilometer scale or the 10 m scale, the geometry is the same.


I would hasten to add, there is a LOT of far smaller ice, between the floes we can resolve - that also is rather obvious.  I suspect there's quite a bit like this about, where we see areas broken up on an obviously larger scale.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Vergent on July 19, 2013, 06:52:29 AM
Quote
A lot of the eastern CAB is starting to look like this(from 2012).

In fairness to Peter, I have to assume that English is his second language.

Vergent
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 19, 2013, 07:29:24 AM
Great work, congratulations, Wipneus!

I am looking forward to a very exciting melt season in the next weeks...

Cheers from Bremen
LK

Welcome to the forum!

Thanks for what appears to be excellent data, it surely gives a lot of pleasure to work with.

Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 19, 2013, 08:20:16 AM
Update 20130718.

Extent: -97k6 (+120k vs 2012)
Area:  -110k2 ( +281k vs 2012)

CAA makes a massive jump downward today. Together with Kara and the last bit of ice in the northern parts of the Hudson that is where the action is, the other regions are on a slow decline.


Updated graphs can be seen in the top post.

The details (in 1000 km2) :

Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   -1.0                    -1.6                    -5.4
               Kara Sea             Barents Sea           Greenland Sea
                  -21.0                    -0.3                    -5.2
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -2.2                     0.4                   -16.2
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                  -37.7                    -6.9                     0.9
             Bering Sea          Sea of Okhotsk            Total Extent
                   -0.3                    -1.1                   -97.6

Area:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   -6.7                   -18.9                    -9.5
               Kara Sea             Barents Sea           Greenland Sea
                   -5.9                    -0.2                     0.5
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                    1.4                     0.4                   -19.3
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                  -46.9                    -1.4                    -2.9
             Bering Sea          Sea of Okhotsk              Total Area
                   -0.3                    -0.5                  -110.2
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 19, 2013, 08:36:57 AM
Region of the day is the Atlantic side of the CAB with what I call the Greenland, Barentsz and Kara sector.
There is quite a lot to notice, the large dark areas in the CAB with concentration between 20-60% looks like it could open real soon now. There is extent expansion: the wind vectors are parallel to the ice edge making the ice move outwards. Slow motion breaking of the fast ice in NE Greenland.

(log in to see attached image)



Title: Re: Home brew AMSR2 extent & area calculation
Post by: Anne on July 19, 2013, 09:06:01 AM
I think the scale of the MODIS imagery also means the ice could be like the picture presented but we'd not see it. It is such a pity the Polar Stern doesn't have an Arctic cruise this year giving us an actual view of the ice. Doesn't look like the Healy is going anywhere far from shore this year either. We could really use a couple of Global Hawks cruising back and forth over the ice to provide better ground truth. Oh well it isn't going to happen so we're stuck guessing wildly.
Polar Stern's sister ship Polar Star is somewhere up there out of Unalaska doing sea trials after her refit (http://www.alaskadispatch.com/article/20130706/coast-guard-refurbished-icebreaker-heads-north). But I haven't been able to find out where, or whether any obs will be made public.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: danp on July 19, 2013, 09:18:30 AM
Polar Stern's sister ship Polar Star is somewhere up there out of Unalaska doing sea trials after her refit (http://www.alaskadispatch.com/article/20130706/coast-guard-refurbished-icebreaker-heads-north). But I haven't been able to find out where, or whether any obs will be made public.

Good find Anne!  Digging around I came across a little info here: http://www.dvidshub.net/image/973522/coast-guard-conducts-arctic-domain-awareness-flight (http://www.dvidshub.net/image/973522/coast-guard-conducts-arctic-domain-awareness-flight)

There are some photos from July 16th of the Polar Star at the edge of the ice in the Chuckchi sea.  There are also some other neat photos taken from various other Arctic overflights, instrument drops, etc.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 19, 2013, 10:42:06 AM
For fun, see attached images (log in etc.)

First a detail of the AMSR2 image above, showing the black area in the top.

Then the same spot in today's MODIS aqua (250m) image. Mentally rotate 45 degrees anti clockwise and squint eyes to remove cloud blurs and improve resolution.

Title: Re: Home brew AMSR2 extent & area calculation
Post by: Neven on July 19, 2013, 11:25:19 AM
Wow, that's really impressive!
Title: Re: Home brew AMSR2 extent & area calculation
Post by: LarsBoelen on July 19, 2013, 04:57:49 PM
Wipneus, maybe you explained elsewhere, but couldn't find it:

Is the fact that the Canadian Archipelagao started at .8 for the first half of 2012 and at .7 for the first half of 2013 caused by a definition change of what counts as CA-area?
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Pmt111500 on July 19, 2013, 05:03:38 PM
Thanks Wipneus for the comparison between AMSR2 and Modis aqua visible, looks like AMSR2 is proving itself to be a great instrument!
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 19, 2013, 05:36:04 PM
Wipneus, maybe you explained elsewhere, but couldn't find it:

Is the fact that the Canadian Archipelagao started at .8 for the first half of 2012 and at .7 for the first half of 2013 caused by a definition change of what counts as CA-area?

Yup, I explained that before, but maybe not very well.
Let me try again,

The AMSR2 3.125 km grid data exists only for 2013, so to compare with 2012 I had to use something else. From the same source comes an SSMIS concentration data, available for 2012 and 2013, but in a different grid: 12.5 km. That is 16 times as big, by area.
Yet the SSMIS 12.5 km data and the AMSR2 3.125 km data are quite similar , see this post:
https://forum.arctic-sea-ice.net/index.php/topic,382.msg9041.html#msg9041 (https://forum.arctic-sea-ice.net/index.php/topic,382.msg9041.html#msg9041)

So it seems 12.5 km or 3.125 km don't matter very much?
Well for the CAA with its narrow channels and straits it does matter somewhat.
Imagine making a 12.5 km grid, and divide the cells in "land" and "sea" cells. Sea cells must contain almost 100% sea, otherwise it is land. Now make a 3.125 km grid by dividing all those grid cells into 16 smaller cells, some of those marked "land", will now contain only sea -> in total there is more sea surface.

The actual numbers are for the total CAA area:
The amsr2 3.125 km grid counts  0.7917134 Mm2
The ssmis 12.5 km grid counts counts 0.7034836 Mm2

I could compensate for that, perhaps in version 0.0.2
Title: Re: Home brew AMSR2 extent & area calculation
Post by: LarsBoelen on July 19, 2013, 11:08:00 PM
Thanks Wipneus,

That totally clarifies it for me! Maybe you can add something to the CAA graph  like "* CAA baseline differs due to grid size change".

I think more people wondered why that was, or maybe they didn't :-)

Lars
Title: Re: Home brew AMSR2 extent & area calculation
Post by: AartBluestoke on July 20, 2013, 01:46:10 AM
given that there are issues with costal pixels anyway, would there be a significant downside to producing numbers at the high resolution with the low resolution ground mask? ie; just ignore that extra area when computing some of the numbers, for the purpose of comparing the 2 datasets?
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 20, 2013, 08:23:45 AM
Update 20130719.

Extent: -26k7 (+182k vs 2012)
Area: -75k1 ( +210k vs 2012)

Slowest extent decline in over 2 weeks. The ESS has the largest decline, in Chukchi extent increased. Area is declining faster, most in the CAB, but also Beaufort and Chukchi lost area. In Laptev and CAA area increased.

For updated images see the top post

The details (in 1000 km2):

Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   -3.3                   -12.3                    -4.9
               Kara Sea             Barents Sea           Greenland Sea
                   -9.3                    -0.3                     3.4
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                    1.7                    -0.4                    -1.7
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   -0.4                    -3.0                     4.4
             Bering Sea          Sea of Okhotsk            Total Extent
                   -0.2                    -0.4                   -26.7

Area:
           Arctic Basin       East Siberian Sea              Laptev Sea
                  -42.9                   -19.8                     9.4
               Kara Sea             Barents Sea           Greenland Sea
                   -8.0                    -0.2                     0.3
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                    2.8                    -0.4                    -1.1
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                    7.8                   -13.9                    -8.6
             Bering Sea          Sea of Okhotsk              Total Area
                   -0.2                    -0.3                   -75.1
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 20, 2013, 08:39:01 AM
Region of the day is Chukchi with ESS. As reported above, Chukchi is gaining extent and loosing area. In other words the ice is spreading and the image is very suggestive of that. That happens in the ESS as well, but solid melting is dominating.

(log in to see attached image)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 20, 2013, 08:48:32 AM
Yesterdays "dark spot" in the CAB continues to make real polynya: the red pixels are grid cells where the average concentration dropped below 15%.

(only visible if you are logged in)

 
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 21, 2013, 08:25:36 AM
Update 20130720.

Extent: -39k8 ( +161k vs 2012)
Area: -52k2 ( +97k vs 2012)

Another day with somewhat lower declines than we have got used to. We are approaching 2012 values though, so it was even slower last year at this time.
Most of the declines are in Chukchi and the ESS, but the CAB may be the one to watch. Area in the CAB has been on the decline more than extent and is now at -93k compared with 2012.
Too match 2012 it will have to go to a sustained -50k/day or so soon.


For updated images see the top post

The details (in 1000 km2):

Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   -7.0                   -11.8                    -3.1
               Kara Sea             Barents Sea           Greenland Sea
                   -2.7                    -0.7                     0.1
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                    1.6                     0.1                     0.8
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   -4.0                    -0.8                   -13.0
             Bering Sea          Sea of Okhotsk            Total Extent
                    0.1                     0.6                   -39.8

Area:
           Arctic Basin       East Siberian Sea              Laptev Sea
                  -25.1                   -19.8                    -3.0
               Kara Sea             Barents Sea           Greenland Sea
                   -5.3                    -0.4                     7.1
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                    2.0                     0.1                     1.6
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                    0.1                    -1.7                    -8.2
             Bering Sea          Sea of Okhotsk              Total Area
                    0.1                     0.4                   -52.2
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 21, 2013, 08:43:06 AM
Region of the day is Laptev (and the CAB Laptev sector).

Wind blows to the upper left in this image, so the ice moves under the Coriolis apparent force to the top explaining the extent increase there.

Right at the bottom is the polynya that I have been following the last two days: it closed again.

(log in to see attached image)

Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 21, 2013, 08:48:05 AM
May be of interest, here are the positions relative to 2012 measured with the SSM/IS instrument, which has shown to be quite comparable with the AMSR2 3.125km data.

Differences in 1000 km2

#### EXTENT ASMR2 3.125 km - SSMIS 12.5 km 2013 DAY 201 ####

           Arctic Basin       East Siberian Sea              Laptev Sea
                  -69.9                    84.1                   105.0
               Kara Sea             Barents Sea           Greenland Sea
                  130.5                    -6.0                  -174.0
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   26.9                   -14.9                     9.8
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   31.3                   200.3                  -161.0
             Bering Sea          Sea of Okhotsk            Total Extent
                   -0.8                     0.1                   161.4

#### AREA ASMR2 3.125 km - SSMIS 12.5 km 2013 DAY 201 ####

           Arctic Basin       East Siberian Sea              Laptev Sea
                  -93.2                    56.9                    84.6
               Kara Sea             Barents Sea           Greenland Sea
                  118.5                    -5.5                  -125.3
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   23.3                   -11.1                     0.9
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   15.9                   178.4                  -145.0
             Bering Sea          Sea of Okhotsk              Total Area
                   -0.8                    -0.1                    97.5
Title: Re: Home brew AMSR2 extent & area calculation
Post by: ChrisReynolds on July 21, 2013, 08:54:41 AM
Wipneus,

Kevin O'Neill just linked to this in comments over at my blog, thought there may be some details in it that you find useful - re boostrap and NASA Team algorithms.
D Notz, 2013, Sea-ice extent provides a limited metric of model performance.
http://www.the-cryosphere-discuss.net/7/3095/2013/tcd-7-3095-2013.pdf (http://www.the-cryosphere-discuss.net/7/3095/2013/tcd-7-3095-2013.pdf)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 21, 2013, 09:20:54 AM
Wipneus,

Kevin O'Neill just linked to this in comments over at my blog, thought there may be some details in it that you find useful - re boostrap and NASA Team algorithms.
D Notz, 2013, Sea-ice extent provides a limited metric of model performance.
http://www.the-cryosphere-discuss.net/7/3095/2013/tcd-7-3095-2013.pdf (http://www.the-cryosphere-discuss.net/7/3095/2013/tcd-7-3095-2013.pdf)

Thanks, I am busy reading about the differences between the different algorithms. This surely looks interesting.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 22, 2013, 07:41:31 AM
The daily update will be delayed a couple of hours today.

In the mean time, here is a difference map between 2012 and 2013, based on the SSMIS concentration data made available by the Uni Hamburg people (see the top post).

The picture for CAA, north coast Greenland is unreliable, due to differences in land/ocean/sea masks, just look at the "big" picture.

(log in to see attached image)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 22, 2013, 09:39:17 AM
Update 20130721.

Extent: -117k3 (+85k vs 2012)
Area:-82k9 (+251k vs 2012)

Chukchi leads followed by ESS and the CAB. Little movement with Beaufort still.

Updated graphs in the top post.

The details in 1000 km2:

Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                  -20.3                   -20.6                     1.0
               Kara Sea             Barents Sea           Greenland Sea
                  -12.7                     0.4                   -14.7
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -4.8                     0.0                    -2.9
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   -9.2                    -3.6                   -28.4
             Bering Sea          Sea of Okhotsk            Total Extent
                   -0.4                    -0.9                  -117.3

Area:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   12.9                   -42.8                    -2.0
               Kara Sea             Barents Sea           Greenland Sea
                   -5.1                     0.2                     2.5
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -5.1                     0.0                    -2.1
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   -3.1                   -14.1                   -23.3
             Bering Sea          Sea of Okhotsk              Total Area
                   -0.3                    -0.6                   -82.9
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 22, 2013, 09:56:00 AM
The region of the day is the Atlantic sector of the CAB again. Three days ago the ice behind Frans Josef land had some quite low concentration grid cells, now some are below the 15% cutoff and officially open water.

(log in to see attached image)

Title: Re: Home brew AMSR2 extent & area calculation
Post by: seaice.de on July 22, 2013, 10:49:30 AM
The region of the day is the Atlantic sector of the CAB again. Three days ago the ice behind Frans Josef land had some quite low concentration grid cells, now some are below the 15% cutoff and officially open water.

That's exactly the region where I expect a big surprise, keep an eye on it!

Have a look at the thickness difference between 2013 and 2012 (from our regional Sea Ice Outlook of July):

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fwww.arcus.org%2Ffiles%2Fresize%2Fsearch%2Fsea-ice-outlook%2F2013%2F07%2Fimages%2Fregional%2Ffigure6-500x503.jpg&hash=d0bb2e04c734c407523cc240906d45f6)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 23, 2013, 08:23:55 AM
Update 20130722.

Extent: -100k7 (+71k  vs 2012)
Area: -80k7 (+400k  vs 2012)

He he, leader in extent decline is Beaufort with the adjacent Chukchi and CAA also joining in. The continuing decline in the CAB is mostly across the Arctic, the Barentsz Sector.

Updated images in the top post.

The details (in 1000 km2):

Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                  -16.6                     1.4                    -6.4
               Kara Sea             Barents Sea           Greenland Sea
                   -9.7                    -0.4                    -6.3
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                  -10.1                    -0.1                    -0.4
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                  -13.9                   -22.0                   -16.7
             Bering Sea          Sea of Okhotsk            Total Extent
                    0.1                     0.3                  -100.7

Area:
           Arctic Basin       East Siberian Sea              Laptev Sea
                    4.8                   -13.4                    -3.8
               Kara Sea             Barents Sea           Greenland Sea
                   -6.0                    -0.2                    -7.3
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                  -10.9                    -0.1                    -0.2
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   -9.9                   -15.7                   -18.2
             Bering Sea          Sea of Okhotsk              Total Area
                    0.0                     0.3                   -80.7
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 23, 2013, 08:33:36 AM
Region of the day is this section with Beaufort, Chukchi, ESS and CAB where most of the action is. No doubt it is the weather ;)

(log in to see attached image)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 24, 2013, 08:24:32 AM
Update 20130722.

Extent: -56k8 ( +140k vs 2012)
Area: -47k5 ( +342k vs 2012)

A slow day, most of the decline is in Laptev with increases in ESS and Chukchi. Beaufort has solid decline of 15k, Beaufort needs about 11k of decline in the next 30 days to melt out.

Updated graphics in the top post.

The details (in 1000 km2 ):

Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   -5.4                     5.6                   -18.5
               Kara Sea             Barents Sea           Greenland Sea
                   -4.9                     0.6                     4.7
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                  -14.0                     0.0                    -9.6
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                  -11.7                   -15.0                    11.4
             Bering Sea          Sea of Okhotsk            Total Extent
                    0.2                    -0.1                   -56.8

Area:
           Arctic Basin       East Siberian Sea              Laptev Sea
                  -11.6                    22.5                    -0.7
               Kara Sea             Barents Sea           Greenland Sea
                   -6.4                     0.3                    -5.1
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -7.1                     0.0                   -11.8
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                  -11.9                    -5.8                    -9.8
             Bering Sea          Sea of Okhotsk              Total Area
                    0.2                    -0.1                   -47.5
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 24, 2013, 08:41:36 AM
It has been about a week ago that the Canadian Archipelago was region of the day. Compared with then the main NW passage is now turning darker.
In the Nares Strait, the iceberg PII-2012 is visible in the middle of the sea ice floes.

(log in to see attached image)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 24, 2013, 08:51:34 AM
NE Greenland: did I miss Espen's announcement that that big broken off fast ice, is now broken in three pieces?

(log in etc):
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 24, 2013, 12:27:27 PM
Animation NE Greenland & Fram Sea Ice

(for those that have logged in)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 24, 2013, 03:26:10 PM
Confirmation on Modis that BigBerg is no more.

(yes, need to log in)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Neven on July 24, 2013, 03:57:29 PM
Animation NE Greenland & Fram Sea Ice

(for those that have logged in)

Not much ice making it South, eh? Isn't this East Greenland Current supposed to be cold?
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 25, 2013, 10:28:25 AM
8:20. As zmaw.de is unreachable, no sea ice concentration data and  the daily update will be delayed if at all :(


10:10 Update: Connection is restored. No new data available.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Artful Dodger on July 25, 2013, 11:06:34 AM
10:10 Update: Connection is restored. No new data available.
Hi Wipneus,

JAXA's last AMSR2 'Missing Data List' entry is for a 43 min "Inclination Adjust Maneuver" conducted on 2013/05/27.

JAXA did conduct a 4-minute "Orbit Raise Maneuver" on 2013/06/23 from 12:59 to 13:03 hrs. But since we've already got July 23 data, that event is likely unrelated to today's problem.

I do see that JAXA has posted Level 2 data for 14 orbits on July 24, and also that L2 data is now starting to flow for July 25 (Level 3 data is not out for July 24 yet, but it's early).

So perhaps UniBremen just lost their fiber link, and they were unable to download the data? If so, they'll catch up soon enough.  8)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 25, 2013, 11:18:19 AM
Lodger,

This data I get from the Hamburg University. Bremen updated their AMSR2 products normally. All of the Uni Hamburg website was unreachable. I don't know how long they were out of communication, perhaps more than 20 hours: the SSMIS data has not been updated either (normal update time 12:00 UTC). SSMIS data comes from NOAA IIRC.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: ivica on July 25, 2013, 11:54:47 AM
Probably unlikely, however...
Any of members from EU experienced power outage today ?
Happened here 8:30 AM ... 9:2x AM this morning (local time). That is quite unusual, we have power outage once or twice per year and those last for a few minutes only. I noticed problems with some internet connections after that.
It's 11:50 AM as I write it, https://sites.google.com/site/apamsr2/home/pngcby32/ (Hamburg ?) is not updated yet.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 25, 2013, 01:04:13 PM
Probably unlikely, however...
Any of members from EU experienced power outage today ?
Happened here 8:30 AM ... 9:2x AM this morning (local time). That is quite unusual, we have power outage once or twice per year and those last for a few minutes only. I noticed problems with some internet connections after that.
It's 11:50 AM as I write it, https://sites.google.com/site/apamsr2/home/pngcby32/ (Hamburg ?) is not updated yet.

Ivica, I update those graphs at the same time of my daily report.

So it goes like this:

AMSR2 instrument on the GCOM-W1 satellite -> JAXA -> Uni Hamburg KlimCampus -> Wipneus -> ASI blog+ASI forum+ ArctischePinguin websites.

Title: Re: Home brew AMSR2 extent & area calculation
Post by: ivica on July 25, 2013, 02:28:18 PM
"Fiber" which connect us with the beach there (http://www.schiffswiki.de/index.php?option=com_content&view=article&id=55&Itemid=63) works, just checked  8)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 25, 2013, 04:07:16 PM
Well, the SSMIS 12.5km concentration data updated for 20130724. The SSMIS extent and area are quite comparable on the long run with this AMSR2 3.125 data, but the day to day changes are a bit bigger.

With the warning that the AMSR2 data may be off, here are the results.

UH SSMIS extent: +42k
UH SSMIS area: -51k

Instead of a regional breakdown, here is a map showing ice increasing over Beaufort-Chukchi-ESS and declining in Laptev.

(you must log in to see the map)

Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 26, 2013, 05:51:13 AM
Update 20130714.

Extent: -12k2 (+230k vs 2012)
Area: -86k6 (+370k vs 2012)

Rather large extent increases for Chukchi and Beaufort. Declines in Laptev and ESS. A large area decline in the CAB.

Details (in 1000 km2):
Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                    1.1                   -12.3                   -19.6
               Kara Sea             Barents Sea           Greenland Sea
                   -1.3                    -0.4                    -4.5
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                    1.5                     0.0                    -2.9
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   -5.7                    12.1                    19.6
             Bering Sea          Sea of Okhotsk            Total Extent
                    0.0                     0.0                   -12.2

Area:
           Arctic Basin       East Siberian Sea              Laptev Sea
                  -79.2                    15.2                   -17.9
               Kara Sea             Barents Sea           Greenland Sea
                   -9.5                    -0.2                    -5.3
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                    1.9                     0.0                    -2.3
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                  -16.6                    -5.8                    33.1
             Bering Sea          Sea of Okhotsk              Total Area
                    0.1                     0.0                   -86.6
Title: Re: Home brew AMSR2 extent & area calculation
Post by: helorime on July 26, 2013, 06:18:43 AM
The storm has blown a lot of ice over to Barrow, which had been ice-free for a while, so I imagine that the ice has blown all over.  http://seaice.alaska.edu/gi/observatories/barrow_webcam (http://seaice.alaska.edu/gi/observatories/barrow_webcam)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 26, 2013, 08:29:04 AM
Update 20130725.

Extent:  -47k1 (+300k  vs 2012)
Area:  -101k6 ( +350k  vs 2012)

As the cyclone is moving west the decline resumes in its wake. It is not only the ice, but also the water vapor brought by an active front may interpreted by the ASI algorithm as ice. ESS is particularly recovering, especially looking at the area.  Chukchi is just starting to recover expect more declines there tomorrow.
Particularly impressing is the area decline in the CAB, with more to come when the cyclone sizzles out.

Have a look at the graphs in the top post.

The details (in 1000 km2):

Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   -0.3                   -16.9                    -2.3
               Kara Sea             Barents Sea           Greenland Sea
                   -4.4                     0.2                   -11.2
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -2.1                     0.0                    -6.6
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   -8.5                    19.7                   -14.3
             Bering Sea          Sea of Okhotsk            Total Extent
                   -0.3                    -0.1                   -47.1

Area:
           Arctic Basin       East Siberian Sea              Laptev Sea
                  -70.8                   -35.5                    -1.0
               Kara Sea             Barents Sea           Greenland Sea
                    0.7                     0.2                   -17.2
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                    0.6                     0.0                    -4.6
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                    3.1                    37.1                   -13.7
             Bering Sea          Sea of Okhotsk              Total Area
                   -0.3                     0.0                  -101.6

Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 26, 2013, 08:43:42 AM
Region of the day is Beaufort and Chukchi. The cyclone center is downward to the right.  Increase in Beaufort is in full swing, Chukchi recovers from that.

(log in to see attached image)

Title: Re: Home brew AMSR2 extent & area calculation
Post by: AartBluestoke on July 26, 2013, 11:45:21 AM
how much does ice-free water warm up? -- ie, could punting the ice over water which melted out a week ago cause significant melting to offset the cooling effect from above?
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 26, 2013, 01:08:54 PM
how much does ice-free water warm up? -- ie, could punting the ice over water which melted out a week ago cause significant melting to offset the cooling effect from above?

When (wind) forces are moving ice outward, I expect the waters moving with it.

Perhaps when the direction reverses: ice compacts and meets resistance, and warmer water can go for the ice.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Richard Rathbone on July 26, 2013, 02:34:22 PM
how much does ice-free water warm up? -- ie, could punting the ice over water which melted out a week ago cause significant melting to offset the cooling effect from above?

When (wind) forces are moving ice outward, I expect the waters moving with it.

Perhaps when the direction reverses: ice compacts and meets resistance, and warmer water can go for the ice.

If you look at the largest area of red pixels in the image of the day, its a band of ice moving outwards and there could be melting of the ice along its trailing edge due to the water motion Wipneus describes.

Title: Re: Home brew AMSR2 extent & area calculation
Post by: Bob Wallace on July 26, 2013, 05:54:56 PM
If you've got some ~1 meter thick ice moving into previously ice-free water how much colder water is it likely taking with it?

The wind has been blowing over ice, it hasn't had an opportunity to cause large waves.  Wouldn't the depth of the ice/water being moved be not much more than the thickness of the ice?  Mostly just the water in between the pieces of ice.

Has the water that has been exposed to sunlight warmed below the top meter or so?  If so, there should be increased bottom melt as the ice slides over warmer near-surface water.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 27, 2013, 08:23:07 AM
Update 20130726.

Extent: -65k1 (+191k vs 2012)
Area: -113k4 (+260k vs 2012)

The ever very variable Greenland sea takes a big share, leaving for the "Arctic" regions only a small decline in extent.
Notable are huge area declines in Beaufort and Chukchi. Temporary cyclone influence, sign of future melts?

The graphs are updated and can be seen in the top post.

The details (in 1000 km2):

Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   -6.1                    -9.0                    -3.5
               Kara Sea             Barents Sea           Greenland Sea
                   -2.5                     0.1                   -25.8
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -4.2                     0.0                    -6.1
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   -1.0                     1.3                    -8.3
             Bering Sea          Sea of Okhotsk            Total Extent
                    0.1                     0.0                   -65.1

Area:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   10.3                    -5.5                   -17.3
               Kara Sea             Barents Sea           Greenland Sea
                   -1.5                     0.1                   -14.2
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -3.9                     0.0                     3.6
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                    2.9                   -57.6                   -30.3
             Bering Sea          Sea of Okhotsk              Total Area
                    0.0                     0.1                  -113.4
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 27, 2013, 08:30:07 AM
Not the region of the day, but that of yesterday: Beaufort and Chukchi. Note that in the  low concentration area some serious polynyas are forming.

(log in to see attached image)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 27, 2013, 08:34:25 AM
Region of the day is Greenland sea. Will it be ice free this year?

(log in to see)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Neven on July 27, 2013, 02:37:48 PM
More topics are being opened lately, and so I think it's time I stickify this one.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Vergent on July 27, 2013, 09:01:59 PM
Wipneus,

Congratulations on your well deserved elevation to rock-star status. Your own personal pinned topic.

In the Beaufort, rising extent crashing area = spreading ice. How close to 15% is it? Bremen has it at an average in the 50-60% range(by eyeball) down from the 80s a week ago. The Met office has it in the 35-65% bin. Any thought of a home brewed concentration map?

Vergent
Title: Re: Home brew AMSR2 extent & area calculation
Post by: danp on July 28, 2013, 01:06:48 AM
4-day animation (through end of day 207, July 26) of Fram strait.  You can see the crumbling ice in the north.  In the full-size version (500m resolution, 9MB, linked below) you can see cracks forming and perhaps more imminent detachments of large sections of fast ice along the Greenland coast.

https://dl.dropboxusercontent.com/s/s95ad8n90iz1w1v/anim207_fram2_143.gif (https://dl.dropboxusercontent.com/s/s95ad8n90iz1w1v/anim207_fram2_143.gif)

(overview of the whole image, along with a subset at full resolution:)
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FGHy6KGZ.gif&hash=b74bb752a93e4de9b4d610a773a80d6e)(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2F41rxk2P.gif&hash=dc489cba8338cc5f7df83745a78cd473)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: jdallen on July 28, 2013, 04:56:45 AM
4-day animation (through end of day 207, July 26) of Fram strait.  You can see the crumbling ice in the north.  In the full-size version (500m resolution, 9MB, linked below) you can see cracks forming and perhaps more imminent detachments of large sections of fast ice along the Greenland coast.


I believe those may represent fairly significant changes in state for the region.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Artful Dodger on July 28, 2013, 08:29:33 AM
In the Beaufort, rising extent crashing area = spreading ice. How close to 15% is it? Bremen has it at an average in the 50-60% range(by eyeball) down from the 80s a week ago. The Met office has it in the 35-65% bin. Any thought of a home brewed concentration map?

Hi Verge,

How does 4 bins for Sea Ice Concentration work for you?
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 28, 2013, 08:32:30 AM
Update 20130727.

Extent: -61k7 (+264k vs 2012)
Area: - 96k3 (+214k vs 2012)

The modest decline in extent is shown in most active regions. The exception is Beaufort that increased, yet the area declined. Area decline is bigger, with notable contributions from CAB, ESS, and CAA and the Beaufort. Chukchi shows the opposite, an increase in area.

You will find the updated graphs in the top post (https://forum.arctic-sea-ice.net/index.php/topic,382.0.html)

The details (in 1000 km2):

Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   -5.6                   -15.8                   -10.4
               Kara Sea             Barents Sea           Greenland Sea
                   -6.0                    -0.4                     1.5
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -7.0                     0.0                    -5.5
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   -5.3                     7.4                   -14.9
             Bering Sea          Sea of Okhotsk            Total Extent
                    0.1                     0.1                   -61.7

Area:
           Arctic Basin       East Siberian Sea              Laptev Sea
                  -22.4                   -21.0                    -9.1
               Kara Sea             Barents Sea           Greenland Sea
                   -8.0                    -0.3                     3.1
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -5.2                     0.0                    -8.5
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                  -20.8                   -13.6                     9.3
             Bering Sea          Sea of Okhotsk              Total Area
                    0.1                     0.0                   -96.3
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 28, 2013, 08:59:56 AM
Time for a peek at the Atlantic side of the Arctic. In Kara, the only ice left behind Svernaya Zemlya looks much tougher to melt but at this rate Kara will be ice free this year. The CAB has been showing small polynyas appearing and disappearing for a while, with large area having concentrations between 50-70%.

(log in to see attached image)

Title: Re: Home brew AMSR2 extent & area calculation
Post by: Vergent on July 28, 2013, 09:05:52 AM

Hi Verge,

How does 4 bins for Sea Ice Concentration work for you?

Lodger,

It reminds me of this.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fchristennantphotography.files.wordpress.com%2F2010%2F02%2Fballoons_small.jpg&hash=b9b2f01e691ee585331949acdc3540fc)

Verge
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Artful Dodger on July 28, 2013, 09:18:31 AM

Hi Verge,

How does 4 bins for Sea Ice Concentration work for you?

Lodger,

It reminds me of this.

Verge

Yup. Blink of a geologic instant.  :-[
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 28, 2013, 10:33:02 AM

In the Beaufort, rising extent crashing area = spreading ice. How close to 15% is it? Bremen has it at an average in the 50-60% range(by eyeball) down from the 80s a week ago. The Met office has it in the 35-65% bin. Any thought of a home brewed concentration map?

Vergent

I haven't figured a way yet that satisfies me. You can either measure it, in the Gimp or similar: the grey's have values 0-100% corresponding to concentration.
Or just use the Bremen maps, they are using the same basic algorithm (ASI) as those from Uni Hamburg, albeit with different versions (5.2 vs 6).

Here is the Bremen map at 3.125km:

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fwww.iup.uni-bremen.de%3A8084%2Famsr2%2FNorthWestPassage_AMSR2_nic.png&hash=087c4e6c5edc429c1d55bb9a6ac226ce)

Title: Re: Home brew AMSR2 extent & area calculation
Post by: jdallen on July 28, 2013, 10:33:35 AM
Time for a peek at the Atlantic side of the Arctic. In Kara, the only ice left behind Svernaya Zemlya looks much tougher to melt but at this rate Kara will be ice free this year. The CAB has been showing small polynyas appearing and disappearing for a while, with large area having concentrations between 50-70%.

(log in to see attached image)

I've been watching the eastern Kara with interest.  Right now, it reminds me of how the Chukchi looked a couple of weeks ago.  It will not last, and when it starts to go, it will happen quickly.

On a side note, with the clouds finally clearing, looking at Lance-Modis, the reduction in concentration across large swaths of the Beaufort is breath-taking.  There's been a huge amount of melt going on out of sight for the last few days. Extent may not have dropped, but SIA certainly has.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 28, 2013, 11:17:55 AM
4-day animation (through end of day 207, July 26) of Fram strait.

Thanks Dan, fascinating as usual. I think you can clearly see the movement of sea ice due to tidal currents through the strait.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 28, 2013, 06:19:51 PM
Here is a color coded ice concentration map of the Beaufort. Coding taken from a Jaxa document.

(time to log in, if you haven't)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Vergent on July 28, 2013, 09:29:10 PM
Here is a color coded ice concentration map of the Beaufort. Coding taken from a Jaxa document.

(time to log in, if you haven't)

OMG, that is efing magnificent! CT, JAXA, NSIDC, MASIE, HYCOM, and the MET office are all blushing with embarrassment. Their products are grade school scribbles in comparison.

Vergent
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Bob Wallace on July 28, 2013, 10:42:47 PM
RE: the fast ice breaking away from the Greenland shore.  Is this a first?

Looking at the CT area record zero was approached in 2002 and 2003.  Does that small space between the bottom of the curve and zero account for the fast ice?

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi619.photobucket.com%2Falbums%2Ftt275%2FBob_Wall%2FGreenlandSeaIceArea.jpg&hash=42c29b7c8facae7ac9db72c27c22e442) (http://s619.photobucket.com/user/Bob_Wall/media/GreenlandSeaIceArea.jpg.html)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 29, 2013, 08:24:57 AM
Update 20130728.

Extent: -98k6 (+372k vs 2012)
Area: +10k5 (+352k vs 2012)

Beaufort is where the action is: big decline in extent and even bigger increase in area show compaction. Further Chukchi and the CAA show big declines, both in extent and area, ESS just in area.

You will find the updated graphs in the top post (https://forum.arctic-sea-ice.net/index.php/topic,382.0.html)

The details (in 1000 km2):

Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   -8.3                    -2.0                    -6.5
               Kara Sea             Barents Sea           Greenland Sea
                   -3.9                    -0.2                     5.5
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -6.5                     0.1                     4.8
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                  -13.1                   -39.8                   -28.9
             Bering Sea          Sea of Okhotsk            Total Extent
                    0.2                     0.0                   -98.6

Area:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   13.5                   -18.5                    -3.9
               Kara Sea             Barents Sea           Greenland Sea
                   -6.9                    -0.1                     3.7
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -6.9                     0.1                     8.3
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                  -20.1                    53.0                   -11.6
             Bering Sea          Sea of Okhotsk              Total Area
                    0.0                     0.0                    10.5

Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 29, 2013, 08:38:22 AM
For the region of the day it cannot be helped, but we keep coming back to the Beaufort. This is not just action, this is flash melting!

(now log in to see the image)
 
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 29, 2013, 09:05:17 AM
The color coded concentration map of the same region.

(still logged on?)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: AartBluestoke on July 29, 2013, 09:33:42 AM
For the region of the day it cannot be helped, but we keep coming back to the Beaufort. This is not just action, this is flash melting!

(now log in to see the image)

how does this description of "flash melting" match with the large area increase? (+53k)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Neven on July 29, 2013, 10:31:39 AM
For the region of the day it cannot be helped, but we keep coming back to the Beaufort. This is not just action, this is flash melting!

(now log in to see the image)

Definitely flash melting, also visible on UB SIC maps, 27th (http://www.iup.uni-bremen.de:8084/amsr2data/asi_daygrid_swath/n6250/2013/jul/asi-AMSR2-n6250-20130727-v5_nic.png) vs 28th (http://www.iup.uni-bremen.de:8084/amsr2data/asi_daygrid_swath/n6250/2013/jul/asi-AMSR2-n6250-20130728-v5_nic.png).

Things are getting really interesting now, with both passages opening up, holes showing up everywhere, and huge swathes of grey mush. I still think this year will end up second, which would be amazing.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 29, 2013, 10:35:52 AM
For the region of the day it cannot be helped, but we keep coming back to the Beaufort. This is not just action, this is flash melting!

(now log in to see the image)

how does this description of "flash melting" match with the large area increase? (+53k)

If you look at the color coded ice concentration maps, you see that a big area with brownish and even yellowish colors turned purple. Day-to-day concentration changes  are not always what they seem to be. The extent changes are a bit more stable (but it never hurts to wait another day and look again).
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Yuha on July 29, 2013, 10:38:55 AM
For the region of the day it cannot be helped, but we keep coming back to the Beaufort. This is not just action, this is flash melting!

how does this description of "flash melting" match with the large area increase? (+53k)

If you look at the color coded ice concentration maps, you see that a big area with brownish and even yellowish colors turned purple. Day-to-day concentration changes  are not always what they seem to be. The extent changes are a bit more stable (but it never hurts to wait another day and look again).

In MODIS image the region of change is under a heavy cloud cover that might be confusing the sensors.

Another possibility is that the cloud cover is associated with the weather phenomenon that is causing the change.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Pmt111500 on July 30, 2013, 05:38:42 AM
thanks for the concentration maps Wipneus. FWIW, I overlayed the two most recent images of Beaufort, and to me this looks like that when the melt pool coverage hits 30-40%, they either drain or the remaining ice disintegrates and melts away. This fits well with my on ground experience with ice in the Baltic, very rarely I've seen Ice coverage of lower than 70% on any substantial area.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Vergent on July 30, 2013, 06:05:41 AM
thanks for the concentration maps Wipneus. FWIW, I overlayed the two most recent images of Beaufort, and to me this looks like that when the melt pool coverage hits 30-40%, they either drain or the remaining ice disintegrates and melts away. This fits well with my on ground experience with ice in the Baltic, very rarely I've seen Ice coverage of lower than 70% on any substantial area.

The contention that Wipneus's concentration maps are confusing melt ponds for reduced concentration is false. there are large areas in the 98-100% bin. These areas are heavily melt ponded. As can be seen in the declouded images elsewhere.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Frapidfire.sci.gsfc.nasa.gov%2Fimagery%2Fsubsets%2FArctic_r05c03%2F2013210%2FArctic_r05c03.2013210.terra.250m.jpg&hash=d922227a6e9c896364572174959adcd7)

Further, Modis images for the same area clearly show low concentration slush in the same areas as the concentration map shows low concentration.

Shoreline experience is different than open water experience. Either the wind blows the ice in, and it is at high concentration, or it blows out and it is gone. Open water is different.

Vergent

edit: typo
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Pmt111500 on July 30, 2013, 06:14:14 AM
Vergent, thanks for the clarification. Yes, you are correct that my experience is almost completely from shoreline. Anyway the there seems to be a 70% limit for ice behavior (it looks to me). But ok, likely not melt ponds, should have checked elsewhere before hasty conclusions.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Vergent on July 30, 2013, 06:38:38 AM
Vergent, thanks for the clarification. Yes, you are correct that my experience is almost completely from shoreline. Anyway the there seems to be a 70% limit for ice behavior (it looks to me). But ok, likely not melt ponds, should have checked elsewhere before hasty conclusions.

I suggest you spend some time on arcticio's excelent zoom "50 days" and familiarize yourself with ice on the sea.

http://www.arctic.io/zoom/n0nJ/0.4967735;0.1594964;5.0796834/cgc-healy-in-the-arctic (http://www.arctic.io/zoom/n0nJ/0.4967735;0.1594964;5.0796834/cgc-healy-in-the-arctic)

Vergent

Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 30, 2013, 08:23:02 AM
Update 20130729.

Extent: -43k6 ( +452k vs 2012)
Area: -101k8 ( +394k vs 2012)

Extent is slower again than area, net divergence. In extent Chukchi has an uptick, the other regions moderate declines. In area there are bigger declines for CAB and ESS, and also Chukchi.

You will find the updated graphs in the top post (https://forum.arctic-sea-ice.net/index.php/topic,382.0.html)

The details (in 1000 km2):

Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   -7.8                    -7.7                    -6.9
               Kara Sea             Barents Sea           Greenland Sea
                   -2.7                     0.1                    -4.6
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -3.4                    -0.1                    -4.1
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   -3.9                    -8.3                     6.0
             Bering Sea          Sea of Okhotsk            Total Extent
                    0.3                    -0.4                   -43.6

Area:
           Arctic Basin       East Siberian Sea              Laptev Sea
                  -28.8                   -31.0                    -7.8
               Kara Sea             Barents Sea           Greenland Sea
                   -3.4                     0.0                    -7.7
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -2.5                    -0.1                    -2.6
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   12.7                   -15.3                   -15.3
             Bering Sea          Sea of Okhotsk              Total Area
                    0.3                    -0.3                  -101.8
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 30, 2013, 08:37:54 AM
Region of the day are ESS and Laptev. There is some really bad ice here that is not likely to last long.

(image can be viewed when you log in)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 30, 2013, 08:45:33 AM
Color coded concentration map of the same region.

(you should be logged in)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Richard Rathbone on July 30, 2013, 11:49:27 AM
Vergent, thanks for the clarification. Yes, you are correct that my experience is almost completely from shoreline. Anyway the there seems to be a 70% limit for ice behavior (it looks to me). But ok, likely not melt ponds, should have checked elsewhere before hasty conclusions.

The algorithms for determining area used by different groups take very different approaches in this region. Wipneus uses data from an algorithm that is very reluctant to move away from 100% while CT is much more aggressive.

CT has the CAB average at about 70% while Wipneus has it at about 95%. If you just look at the colours, they tell much the same story, but if you look at the numbers you have to be careful how you draw conclusions because the numbers vary enormously from one product to the other.

CT at 70% and Wipneus at 70% are not the same thing at all. CT at 70% probably is ice with melt ponds on it. Wipneus at 95% probably is ice with melt ponds on top of it, but Wipneus at 70% is probably rotten ice on the verge of melting out.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 30, 2013, 12:21:15 PM

The algorithms for determining area used by different groups take very different approaches in this region. Wipneus uses data from an algorithm that is very reluctant to move away from 100% while CT is much more aggressive.
(...)
CT at 70% and Wipneus at 70% are not the same thing at all.

Richard, you are hitting the nail on its head!

I suspect CT is using the algorithm "NASA Team", same as the NSIDC extent index. The "NASA Team" algorithm is known to have this kind of bias, even by its designers.

That is a bias with rival algorithms, but also confirmed with radar and optical imaging, satellite, by air and from ships.

I am using data that was calculated by the Uni Hamburg sea ice group using their ARTIST Sea Ice (ASI) algorithm. Jaxa/IJIS is using the "Bootstrap" algorithm. Both have less bias with other measurements than CT. There is a newer version of the "NASA Team" algorithm, that gives similar performance.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: kynde on July 30, 2013, 03:26:55 PM
Would it be difficult to whip up a concentration distribution graph from your calculations?
(where y would be relative amount of given concentration in x, perhaps barring 0% and 100% so that they won't screw up the scale)

Short term changes and shifts there could be interesting, perhaps provide some insight into what might be happening next.

I'm not sure if this has been asked already somewhere or if such a graph is already available somewhere and I just haven't stumbled onto it yet. If that's the case, sorry for the noise.

edit: forgot to say thanks for all the hard work in here, I frequent this thread more than any other "news outlet" in the net :)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 31, 2013, 08:27:38 AM
Update 20130730.

Extent: -12k2 (+492k vs 2012)
Area: -115k (+265k vs 2012)

The decline is still quite slow. Only partially explained by a recovery in the Beaufort and Chukchi from the flash melt after the cyclone passage, only the CAA shows a substantial extent drop.
Area in contrast is still strong especially in the Beaufort, CAA , ESS and in lesser degree, the CAB.

 
You will find the updated graphs in the top post (https://forum.arctic-sea-ice.net/index.php/topic,382.0.html)

The details (in 1000 km2):

Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   -3.1                    -7.4                    -1.3
               Kara Sea             Barents Sea           Greenland Sea
                   -1.1                     0.6                    -1.2
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -2.7                     0.0                    -2.3
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                  -12.1                    15.6                     3.1
             Bering Sea          Sea of Okhotsk            Total Extent
                   -0.1                    -0.1                   -12.2

Area:
           Arctic Basin       East Siberian Sea              Laptev Sea
                  -15.7                   -31.3                    -4.8
               Kara Sea             Barents Sea           Greenland Sea
                    0.9                     0.3                    -0.1
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -0.5                     0.0                    -0.3
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                  -20.3                   -43.5                     0.6
             Bering Sea          Sea of Okhotsk              Total Area
                   -0.1                    -0.1                  -115.0
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 31, 2013, 08:40:14 AM
Region of the day is the Atlantic side of the CAB, with the stubborn iced corner in Kara visible.
The low concentration area's behind Franz Josef Land and toward the Laptev sea are growing and deepening.

(log in to see attached image)

Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on July 31, 2013, 08:48:03 AM
And the color coded concentration map for the same region.

(still logged in?)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 01, 2013, 08:19:49 AM
Update 20130731.

Extent: -55k9 (+527k vs 2012)
Area: -10k2 (+331k vs 2012)

Continuing slow declines, both extent and Area. Most active in the CAA, Beaufort and Chukchi.
 
You will find the updated graphs in the top post (https://forum.arctic-sea-ice.net/index.php/topic,382.0.html)

The details (in 1000 km2):


Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   -4.5                    -5.9                    -7.6
               Kara Sea             Barents Sea           Greenland Sea
                   -2.9                    -0.2                     3.5
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -0.2                     0.1                    -4.1
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                  -14.6                    -9.1                   -10.2
             Bering Sea          Sea of Okhotsk            Total Extent
                   -0.2                     0.0                   -55.9

Area:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   21.5                     5.6                    -6.0
               Kara Sea             Barents Sea           Greenland Sea
                   -2.6                    -0.1                     4.4
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                    0.6                     0.1                   -12.5
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                  -10.2                     8.8                   -19.6
             Bering Sea          Sea of Okhotsk              Total Area
                   -0.1                     0.0                   -10.2


Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 01, 2013, 08:33:21 AM
Canadian Archipelago is region of the day. Work is in progress to make the southern branch of the NW passage navigable.

(log in to see attached image)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 01, 2013, 08:43:33 AM
Color coded concentration map of the same region.

(attached image, log in to see)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: DavidR on August 01, 2013, 03:23:22 PM
The AMSR2 area and extent figures appear to be moving completely  differently  to the NSIDC extent and CT Area figures over the past week. 

CT Area shows only  a 40K Km*2 drop in a week whereas AMSR2 seems to indicate a decline at the same rate as last year ~ 360K Km*2.

AMSR2 extent shows a small decline while NSIDC extent shows ~ 300K Km*2  decline.

The CT area figure seems totally  anomalous. Is there a reasonable explanation?

Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 01, 2013, 04:51:49 PM
differences last 7 days



amsr2-area   : -527k7
amsr2-extent: -384k3
CTarea          :  -40k5
nsidc-extent  : -410k3
ijis-extent      : -324k4
[/tt]

the outlier in this list is clearly the CT area, but if I had the data I guess Arctic Roos Norsex area would be more like CT. See attached graph.

(log in to see attached graph)

I don't doubt that the underlying cause are the algorithms used to calculate ice concentration. I that respect I tend to trust my amsr2-area calculation more than CT to reflect the "true" area. That is not the same thing as saying it is more useful (in case anybody protests).
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Richard Rathbone on August 01, 2013, 05:39:21 PM

The CT area figure seems totally  anomalous. Is there a reasonable explanation?

Divide the arctic up into areas that are ice sticking up out of the water, open water, and water with ice underneath it.

If all of the arctic fits into the first two categories, then the algorithms report more or less the same concentration. However, where there is water on top of ice, some algorithms report this as ice and some report it as water, and this can result in enormous differences, both in the concentration and in the rate of change of the concentration.

Its something like an order of magnitude difference in the initial amount of melt. e.g. when CT drops from 100 to 90, Wipneus (ASI based) drops from 100 to 99 and the differences can go at least as high as 25%, CT had the CAB concentration at 70% when Wipneus had it at 95% a few days ago. A big reason for the water on ice region is melt ponds. When melt ponds form, CT area drops fast, because it sees them as water, and when they drain it recovers. When a change in the weather causes surface melt across a lot of the arctic at the same time, CT area falls off a cliff and if the weather changes and the ponds drain it bounces back up again.

The differences at the 15% level are less extreme than at the 90% level, but they are still there. I don't know whether they are large enough to explain the reported extents or not. I don't pay much attention to short term changes because the signal is noisy and differentiating a noisy signal just gives garbage numbers. However, as the areas being reported differ by over 1e12 m2 differences in the rate of change of order 1e10 short term and 1e11 medium term can easily result from the different calculation methods.

Title: Re: Home brew AMSR2 extent & area calculation
Post by: seaice.de on August 01, 2013, 07:07:16 PM
differences last 7 days

I don't doubt that the underlying cause are the algorithms used to calculate ice concentration. I that respect I tend to trust my amsr2-area calculation more than CT to reflect the "true" area. That is not the same thing as saying it is more useful (in case anybody protests).

For your information find attached a difference plot of CT (F17, NASA-TEAM) and your home brew data (AMSR2, ASI). I don't now if the coastal-spillover sums up to a significant number but it certainly can not be ignored.
Title: Beaufort forecasted to get persistent HP over the next week
Post by: paulklem on August 01, 2013, 11:07:30 PM
The storm shown in the long range forecast a week ago didn't pan out. But the current forecast shows a persistent HP over the CA, Alaska, and the Beaufort, with a LP cell moving around the CAB over at least the next week. We are late in the season for a lot of insolation, but the Beaufort sea and CA should still pick up a lot of heat and see some higher than normal temps.  We could see a significant weakening of the ice pack there, and if the LP system in the CAB eventually develops into a storm (not very strong, according to forecasts), the ice pack at lower latitudes should deteriorate substantially.

The extensive cloud cover over the Beaufort and Chukchi in June and July, along with a persistently high ice extent in these regions during the insolation top melt season, likely significantly reduced heat buildup.
But the conditions should cause the Beaufort ice pack to weaken over the next week.

I really appreciate the regional extent and area data you can generate... isolating regional data allows observations linking ice pack melt and damage to weather events.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 02, 2013, 08:19:41 AM
Update 20130801.

Extent: -46k1 (+504k vs 2012)
Area: -49k7 (+369k vs 2012)

Continuing slow declines. Highest decline in the CAB, especially area. CAA did an increase after some days of melting.
 
You will find the updated graphs in the top post (https://forum.arctic-sea-ice.net/index.php/topic,382.0.html)

The details (in 1000 km2):


Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                  -19.5                    -5.0                    -0.5
               Kara Sea             Barents Sea           Greenland Sea
                   -5.1                    -0.4                   -11.5
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -3.8                    -0.1                    -5.1
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   13.8                    -4.8                    -3.3
             Bering Sea          Sea of Okhotsk            Total Extent
                   -0.7                    -0.2                   -46.1

Area:
           Arctic Basin       East Siberian Sea              Laptev Sea
                  -68.7                    -5.9                     7.1
               Kara Sea             Barents Sea           Greenland Sea
                   -4.3                    -0.2                   -11.9
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -2.7                    -0.1                    -4.2
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   28.8                     1.8                    11.4
             Bering Sea          Sea of Okhotsk              Total Area
                   -0.6                    -0.1                   -49.7

Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 02, 2013, 08:33:10 AM
The numbers spoke already, the action there is is in the CAB. It is in the Atlantic region, which is today's region. Will the many small polynyas now persist? Or are they gone when the small ridge of high pressure that I think is over the region disappears?

(the image is attached, only viewable for those that are logged in)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 02, 2013, 08:42:04 AM
And the color coded concentration map of the same region.

(visible when logged in)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 02, 2013, 09:11:32 AM
differences last 7 days

I don't doubt that the underlying cause are the algorithms used to calculate ice concentration. I that respect I tend to trust my amsr2-area calculation more than CT to reflect the "true" area. That is not the same thing as saying it is more useful (in case anybody protests).

For your information find attached a difference plot of CT (F17, NASA-TEAM) and your home brew data (AMSR2, ASI). I don't now if the coastal-spillover sums up to a significant number but it certainly can not be ignored.

Thank you.
In many places, the CT (F17,NASA-TEAM) shows bigger concentration deficits than ASI, AMSR2. But there are exceptions eg in the Beaufort.
I think I see what you mean by the coastal spillover. This image, but also the CT concentration maps, shows considerable ice in the Canadian Archipelago in some places where ASI-AMSR2 , but also MODIS-TERRA show open water. Look in Nares strait and southern NW passage.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: seaice.de on August 02, 2013, 11:38:22 AM
Quote
This image, but also the CT concentration maps, shows considerable ice in the Canadian Archipelago in some places where ASI-AMSR2 , but also MODIS-TERRA show open water. Look in Nares strait and southern NW passage.

This could be an effect of the coastal-spillover. Keep in mind that the resolution of 19 GHz SSMIS is only about 69 x 43 km^2.  Have a look at http://www.seaice.de/Maass_Tellus_2010.pdf (http://www.seaice.de/Maass_Tellus_2010.pdf)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 03, 2013, 08:22:13 AM
Update 20130802.

Extent: -80k7 (+411k vs 2012)
Area: -27k5 (+434k vs 2012)

Big extent decline in Beaufort and substantial declines in the CAB and ESS. The CAA increased in extent but the area declined.

 
You will find the updated graphs in the top post (https://forum.arctic-sea-ice.net/index.php/topic,382.0.html)

The details (in 1000 km2):


Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                  -25.0                   -12.3                    -3.9
               Kara Sea             Barents Sea           Greenland Sea
                   -3.6                    -0.2                   -12.8
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -0.1                     0.0                     4.8
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   11.4                   -40.3                     1.1
             Bering Sea          Sea of Okhotsk            Total Extent
                    0.0                     0.0                   -80.7

Area:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   10.3                   -14.9                     8.8
               Kara Sea             Barents Sea           Greenland Sea
                   -1.0                    -0.2                    -2.3
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -1.7                     0.0                     2.5
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                  -19.0                    -2.2                    -7.8
             Bering Sea          Sea of Okhotsk              Total Area
                    0.0                     0.0                   -27.5

Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 03, 2013, 08:28:43 AM
The Beaufort with a huge decline is shown as region of the day. I am not sure how the winds are blowing, but it looks like compaction to me.

(log in to see attached image)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 03, 2013, 08:36:23 AM
Color coded concentration map of the area around the North Pole. Never this season was the concentration here so low.

(log in to see attached image)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: slow wing on August 03, 2013, 12:21:05 PM
This thread rocks, Wipneus!  :)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 04, 2013, 08:25:58 AM
Update 20130803.

Extent: -69k4 (+447k vs 2012)
Area: -40k0 (+493k vs 2012)

Beaufort and CAA doing the big drops today. Kara seems to make an effort to do something about that stubborn fast ice that is blocking the NE passage. I mostly ignore the Greenlands sea: it is doing a large upswing today that may reverse tomorrow.
 
You will find the updated graphs in the top post (https://forum.arctic-sea-ice.net/index.php/topic,382.0.html)

The details (in 1000 km2):


Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   -0.8                   -15.0                    -4.1
               Kara Sea             Barents Sea           Greenland Sea
                   -9.6                     0.1                    19.2
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -2.7                     0.0                    -1.4
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                  -27.1                   -35.0                     7.1
             Bering Sea          Sea of Okhotsk            Total Extent
                    0.0                     0.0                   -69.4

Area:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   -5.6                    -2.3                     0.8
               Kara Sea             Barents Sea           Greenland Sea
                   -7.4                     0.0                    18.0
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -1.6                     0.0                     5.7
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                  -17.7                   -32.5                     2.5
             Bering Sea          Sea of Okhotsk              Total Area
                    0.0                     0.0                   -40.0

Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 04, 2013, 08:52:28 AM
Region of the day is Kara with that stubborn ice, which has a polynya forming. "Laptev bite" on the left is not biting through.

(log in to see attached image)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 04, 2013, 08:53:32 AM
And the color coded concentration map.

(attached, log in to see)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 05, 2013, 08:20:52 AM
Update 20130804.

Extent: -41k1 (+608k vs 2012)
Area: -58k8 (+490k vs 2012)

Relative slow day again. In the ESS the decline shows the demise of a lot of low concentration ice. Also in Beaufort the ice keeps retreating and loosing in concentration.
Nowhere is the surprising behavior of the CT area numbers visible.
 
You will find the updated graphs in the top post (https://forum.arctic-sea-ice.net/index.php/topic,382.0.html)

The details (in 1000 km2):


Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                    2.6                   -15.1                    -4.5
               Kara Sea             Barents Sea           Greenland Sea
                   -0.7                    -0.3                     6.7
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -1.6                     0.0                    -7.8
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   -5.6                   -12.4                    -2.3
             Bering Sea          Sea of Okhotsk            Total Extent
                   -0.1                     0.0                   -41.1

Area:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   -8.9                   -19.1                   -10.6
               Kara Sea             Barents Sea           Greenland Sea
                   -0.7                    -0.2                    -5.0
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -1.8                     0.0                    -4.8
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                    9.2                   -21.3                     4.5
             Bering Sea          Sea of Okhotsk              Total Area
                   -0.1                     0.0                   -58.8

Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 05, 2013, 08:38:24 AM
Region of the day is this part of the East CAB, with the ESS and Laptev. The Arctic Basin was not very remarkable in its net extent/area numbers, but on this side the little polynyas are growing in larger numbers (extent increases are on the Atlantic side).

(log in to see this attached image)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 05, 2013, 08:46:04 AM
The color coded concentration map of the same region.

(attached, need to log in to see)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: iceman on August 05, 2013, 09:01:49 PM
Looks like the track of the nascent cyclone will take the low almost directly over the centre of this image two days from now, with lots of wind stirring up the low-concentration zone in the interior of the ice.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 06, 2013, 08:23:58 AM
Update 20130805.

Extent: -42k2 (+663k vs 2012)
Area: -74k4 (+563k vs 2012)

Slow day again and the gap with 2012 widening. Declines in the CAA and Chukchi, small area decline in the CAB and that is about it.
 
You will find the updated graphs in the top post (https://forum.arctic-sea-ice.net/index.php/topic,382.0.html)

The details (in 1000 km2):


Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                    2.7                     0.1                    -5.1
               Kara Sea             Barents Sea           Greenland Sea
                    0.6                     0.1                    -6.1
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                    1.3                     0.0                    -3.2
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                  -19.7                     0.1                   -13.1
             Bering Sea          Sea of Okhotsk            Total Extent
                    0.0                     0.0                   -42.2

Area:
           Arctic Basin       East Siberian Sea              Laptev Sea
                  -12.7                     4.3                    -2.8
               Kara Sea             Barents Sea           Greenland Sea
                   -3.3                     0.0                    -4.7
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                    4.1                     0.0                    -8.7
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                  -29.7                    -5.3                   -15.7
             Bering Sea          Sea of Okhotsk              Total Area
                    0.0                     0.0                   -74.4

Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 06, 2013, 08:34:22 AM
Region of the day is the CAA. Only a few places are blocking the southern branch of the NW passage now. Nothing is flowing, eg the Nares Strait.

(attached image, log in to view)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 06, 2013, 08:41:09 AM
Color coded concentration map of the same region.

(attached as well, log in to see)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 07, 2013, 10:17:03 AM
Update 20130806.

Extent: -83k7 (+825k vs 2012)
Area: -41k1 (+666k vs 2012)

ESS and Chukchi are taking bad hits, not entirely unexpected.
 
You will find the updated graphs in the top post (https://forum.arctic-sea-ice.net/index.php/topic,382.0.html)

The details (in 1000 km2):


Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                    2.3                   -37.5                    -1.5
               Kara Sea             Barents Sea           Greenland Sea
                    1.9                     0.9                   -12.3
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -4.7                     0.0                     1.9
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   -9.5                     5.9                   -31.1
             Bering Sea          Sea of Okhotsk            Total Extent
                    0.0                     0.0                   -83.7

Area:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   18.2                     5.8                    -9.0
               Kara Sea             Barents Sea           Greenland Sea
                  -11.2                     0.5                     0.3
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -3.2                     0.0                    -1.0
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   -4.0                   -21.1                   -16.4
             Bering Sea          Sea of Okhotsk              Total Area
                    0.0                     0.0                   -41.1

Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 07, 2013, 10:23:37 AM
ESS and Chukchi are of course region of today.

(log in to see attached image)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 07, 2013, 10:38:53 AM
And the color coded concentration map of the region.

While the margins of the ice pack are loosing ice and concentration drops, in the interior purples have appeared where in the past few days the concentration was well below that. I expect this to return when water vapor and liquid water in clouds go down after the cyclone's passage.

(image attached, log in to see)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Pmt111500 on August 07, 2013, 12:33:48 PM
Couple of tries to overlay AMSR2 images 04082013 and 06082013, no idea what the scale on these would be, but the intention was to identify locations of greatest changes. I don't know how well I succeeded.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 08, 2013, 08:40:12 AM
Update 20130807.

Extent: -80k3 (+784k vs 2012)
Area: -1k4 (+710k vs 2012)

The extent in the ESS keeps declining big way, now in the company of Beaufort. In the CAB, sea ice area increased, for a real low September minimum it should decline big way by now.
 
You will find the updated graphs in the top post (https://forum.arctic-sea-ice.net/index.php/topic,382.0.html)

The details (in 1000 km2):


Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                    5.0                   -34.2                    -3.6
               Kara Sea             Barents Sea           Greenland Sea
                   -8.5                    -0.4                     1.1
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -1.1                     0.0                    -4.3
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   -5.3                   -26.7                    -2.5
             Bering Sea          Sea of Okhotsk            Total Extent
                    0.0                     0.0                   -80.3

Area:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   42.3                   -36.9                    -6.9
               Kara Sea             Barents Sea           Greenland Sea
                   -5.6                    -0.3                    11.1
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -1.1                     0.0                    -3.4
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   -9.6                     1.3                     7.7
             Bering Sea          Sea of Okhotsk              Total Area
                    0.0                     0.0                    -1.4

Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 08, 2013, 08:51:17 AM
The action is nearly all in Beaufort, Chukchi and ESS, therefore about the same region of the day. What will the cyclone do with the low concentration ice in the CAB?

(log in and see attached image)

Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 08, 2013, 09:00:51 AM
And the color coded concentration map of the same. Compare the interior of the ice, lots of yesterday's purples appear now (again) as low concentration ice.

(attached image is only visible when logged in)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 08, 2013, 09:11:46 AM
Extra, the "stubborn" ice in the Kara Sea that is blocking the North (East) Passage. Slowly the melt is making progress, concentration is dropping and the polynyas are growing.

(log in to see attached image)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 09, 2013, 08:23:43 AM
Update 20130808.

Extent: -136k4 (+596k vs 2012)
Area: -254k0 (+465k vs 2012)

After some rather dull days, the numbers today show that serious melt figures can still be produced. Huge extent declines in the CAA, ESS and Beaufort. Area declines are even bigger, with the CAB taking the largest bite. 
 
You will find the updated graphs in the top post (https://forum.arctic-sea-ice.net/index.php/topic,382.0.html)

The details (in 1000 km2):


Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                  -10.1                   -32.3                    -4.7
               Kara Sea             Barents Sea           Greenland Sea
                   -3.3                     0.5                    -6.5
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -2.8                     0.0                    -9.0
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                  -52.0                   -21.3                     5.2
             Bering Sea          Sea of Okhotsk            Total Extent
                    0.0                     0.0                  -136.4

Area:
           Arctic Basin       East Siberian Sea              Laptev Sea
                  -72.8                   -48.1                     1.6
               Kara Sea             Barents Sea           Greenland Sea
                    1.0                     0.4                   -14.9
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -5.5                     0.0                    -5.4
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                  -70.6                   -39.3                    -0.3
             Bering Sea          Sea of Okhotsk              Total Area
                    0.0                     0.0                  -254.0

Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 09, 2013, 08:44:53 AM
Region of the day is the Canadian Archipelago. The NW passage looks now almost passable by the southern route, it is worked on har it seems. Further some fjords in the Ellesmere are showing sudden melting, this could well be (it is even likely) and artifact. Contamination from the nearby land on the microwave brightness makes the measurement uncertain.
The PII iceberg in the Nares Strait can be seen as a bright spot in the low concentration ice field.

(log in to see attached image)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 09, 2013, 08:49:46 AM
Color coded concentration map of the same region.

(this image is attached as well, log in to see)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 09, 2013, 08:58:44 AM
As extra, the ESS corner that we showed the last two days again. The polynya's in the CAB are growing. At the lower right the pole hole, with a small polynya stiil on the edge.

(log in to see all this)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Artful Dodger on August 09, 2013, 11:09:55 AM
Further some fjords in the Ellesmere are showing sudden melting, this could well be (it is even likely) and artifact. Contamination from the nearby land on the microwave brightness makes the measurement uncertain.
Hi Wipneus,

As always, thanks for the outstanding work with the AMSR2 data. Gracias!

I think the ice-out in the Ellesmere fjords is real, based on the MODIS visible imagery for Aug 8, 2013. The green tint in the open water confirms the presence of an algal bloom, which is a sure sign of above freezing water temps.  8)

The following image is attached from this lance MODIS source (http://rapidfire.sci.gsfc.nasa.gov/imagery/subsets/?subset=Arctic_r03c03.2013220.aqua.500m).
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 09, 2013, 12:12:11 PM
Further some fjords in the Ellesmere are showing sudden melting, this could well be (it is even likely) and artifact. Contamination from the nearby land on the microwave brightness makes the measurement uncertain.
Hi Wipneus,

As always, thanks for the outstanding work with the AMSR2 data. Gracias!

I think the ice-out in the Ellesmere fjords is real, based on the MODIS visible imagery for Aug 8, 2013. The green tint in the open water confirms the presence of an algal bloom, which is a sure sign of above freezing water temps.  8)

The following image is attached from this lance MODIS source (http://rapidfire.sci.gsfc.nasa.gov/imagery/subsets/?subset=Arctic_r03c03.2013220.aqua.500m).

Yes, I saw that too. I probably should rephrase it to, "somehow today we do not see the false ice caused by spillover from the nearby land".
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Bob Wallace on August 09, 2013, 07:42:22 PM
As extra, the ESS corner that we showed the last two days again. The polynya's in the CAB are growing. At the lower right the pole hole, with a small polynya stiil on the edge.

(log in to see all this)

What might be really helpful is to show earlier/latest images side by side.  It might be necessary to crop off some of the less interesting parts to fit them on the page.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 10, 2013, 08:20:18 AM
Update 20130809.

Extent: -61k9 (+742k vs 2012)
Area: -75k7 (+615k vs 2012)

Beaufort had a strong decline, followed by ESS, Chukchi and Kara. The CAB's extent did not change much, but its area fell considerably.
 
You will find the updated graphs in the top post (https://forum.arctic-sea-ice.net/index.php/topic,382.0.html)

The details (in 1000 km2):


Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                    2.2                   -15.1                    -4.6
               Kara Sea             Barents Sea           Greenland Sea
                  -10.3                    -1.1                     6.4
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                    4.1                     0.0                    -1.2
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   -6.6                   -25.5                   -10.1
             Bering Sea          Sea of Okhotsk            Total Extent
                    0.0                     0.0                   -61.9

Area:
           Arctic Basin       East Siberian Sea              Laptev Sea
                  -73.7                     9.0                     3.3
               Kara Sea             Barents Sea           Greenland Sea
                   -5.7                    -0.8                     2.8
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                    4.6                     0.0                    -2.0
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                    6.4                   -13.4                    -6.2
             Bering Sea          Sea of Okhotsk              Total Area
                    0.0                     0.0                   -75.7
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 10, 2013, 08:50:27 AM
Region of the day is the Atlantic sector of the CAB. This is if I'm not mistaken where the cyclone lies now. Little polynya's near the pole hole keep appearing in spite of the moisture and clouds that hinder the  89GHz microwave channels that the hi res concentration maps are based on.

(log in to see attached image)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 10, 2013, 08:56:15 AM
Color coded concentration map of the same region.

(log in to see)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 11, 2013, 08:29:07 AM
Update 20130810.

Extent: -55k2 (+729k vs 2012)
Area: -75k6 (+697k vs 2012)

Beaufort had the biggest loss, followed at distance by ESS, Laptev and Kara. In extent the CAB has only a marginal decline and does not look like it is going to make the huge drop that happened in 2012. In area however, it is making that drop. CAB extent is now 4.15 Mm2, area is 3.70 Mm2, a compacting potential of 450k.
 
You will find the updated graphs in the top post (https://forum.arctic-sea-ice.net/index.php/topic,382.0.html)

The details (in 1000 km2):


Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   -4.2                   -10.1                    -9.2
               Kara Sea             Barents Sea           Greenland Sea
                   -9.1                     0.2                     0.5
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                    0.0                     0.0                    -5.2
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                    8.5                   -23.7                    -2.9
             Bering Sea          Sea of Okhotsk            Total Extent
                    0.0                     0.0                   -55.2

Area:
           Arctic Basin       East Siberian Sea              Laptev Sea
                  -28.2                    -0.7                   -18.4
               Kara Sea             Barents Sea           Greenland Sea
                  -11.5                     0.1                    -4.8
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                    0.0                     0.0                    -3.3
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   -7.1                    -3.2                     1.7
             Bering Sea          Sea of Okhotsk              Total Area
                    0.0                     0.0                   -75.6

Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 11, 2013, 08:43:01 AM
No compaction on the Atlantic section of the CAB. More polynya's are appearing than before in this season. The polynya near the edge of the pole hole is getting company.

(;log in to see attached image)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 11, 2013, 08:49:41 AM
And the color coded concentration map of the same region.

(also attached, log in to see)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: iceman on August 11, 2013, 03:46:41 PM
The HYCOM map of Ice Speed and Drift (if it is in fact a nowcast) shows movement that would cause some dispersion in this region, and greater compaction on the opposite side of the low.
    If the Laptev Bite opens up in the next few weeks, the swathe of relatively thick ice N and E of Severnaya Zemlya will detach.  Another candidate for detachment is the thick patch NW of Wrangel Island, though this doesn't seem imminent based on forecast wind direction.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 12, 2013, 08:17:36 AM
Update 20130811.

Extent: -65.3 (+792k vs 2012)
Area: -35.2 (+785k vs 2012)

For extent I can sum this up simply as CAA, ESS and Laptev. For area, the CAB (again) looses area while staying about level in extent.
 
You will find the updated graphs in the top post (https://forum.arctic-sea-ice.net/index.php/topic,382.0.html)

The details (in 1000 km2):


Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                    2.1                   -15.7                   -18.6
               Kara Sea             Barents Sea           Greenland Sea
                   -7.1                     0.0                    -4.5
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -5.7                     0.0                    -0.5
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                  -22.0                     5.1                     1.6
             Bering Sea          Sea of Okhotsk            Total Extent
                    0.0                     0.0                   -65.3

Area:
           Arctic Basin       East Siberian Sea              Laptev Sea
                  -15.0                    -7.6                    -6.6
               Kara Sea             Barents Sea           Greenland Sea
                   -8.6                     0.0                    -2.0
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -4.3                     0.0                    -0.5
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   -1.5                     4.1                     6.8
             Bering Sea          Sea of Okhotsk              Total Area
                    0.0                     0.0                   -35.2

Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 12, 2013, 08:31:31 AM
Region of the day is the Siberian section of the CAB with peripherals. There is broad melting from west to east and enough movement (polynya's popping and plopping) in the low concentration interior of the CAB. The North (East) passage is still in the works.

(image attached, log in to see)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 12, 2013, 08:41:10 AM
And the color coded concentration map of the region.

(log in to see that map)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 13, 2013, 08:18:47 AM
Update 20130812.

Extent: +18k0 (+1046k vs 2012)
Area: -10k5 (+860k vs 2012)

An uptick in extent makes the gap with 2012 over 1Meg.  The increase today is caused in the Beaufort, there is a slight northern wind but if that is enough explanation? The ESS is the only region with a large extent loss. CAB continues to loose area without much change in extent.

 
You will find the updated graphs in the top post (https://forum.arctic-sea-ice.net/index.php/topic,382.0.html)

The details (in 1000 km2):


Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   -3.6                   -18.3                    -1.5
               Kara Sea             Barents Sea           Greenland Sea
                   -2.8                    -0.1                     9.0
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -4.0                     0.0                    -3.0
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                    8.1                    37.9                    -3.8
             Bering Sea          Sea of Okhotsk            Total Extent
                    0.0                     0.0                    18.0

Area:
           Arctic Basin       East Siberian Sea              Laptev Sea
                  -22.8                   -10.8                    -3.6
               Kara Sea             Barents Sea           Greenland Sea
                   -2.2                     0.0                     6.6
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -2.8                     0.0                    -1.2
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   28.1                     0.3                    -2.1
             Bering Sea          Sea of Okhotsk              Total Area
                    0.0                     0.0                   -10.5

Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 13, 2013, 08:33:01 AM
Beaufort is the region of the day, showing a rather large extent increase with a level area. As the image shows, the increase happens in a low concentration area. Perhaps the northern winds have caused some melt pool freeze: melt pools affect the ASI algorithm just as all algorithms.

(image attached, log in to view)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 13, 2013, 08:38:52 AM
And the color coded concentration map for the Beaufort.

(log in to see)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 13, 2013, 08:46:33 AM
The ESS is not only loosing ice from the ice edge inward, polynyas in the interior are growing and expanding.

(login to see more)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Artful Dodger on August 13, 2013, 09:45:00 AM
Beaufort is the region of the day, showing a rather large extent increase with a level area. As the image shows, the increase happens in a low concentration area. Perhaps the northern winds have caused some melt pool freeze: melt pools affect the ASI algorithm just as all algorithms.
Hi Wipneus,

I think there is a possibility that the change in sea ice concentration in the Beaufort sea on Aug 12/2013 is an artifact of clouds obscuring the sensor.

Do you have the ability to overlay your SIC charts with MODIS bands 3-6-7 imagery? It'd be informative to see if the area of newly reported sea ice extent >15% aligns with the band of cloud from the tile r05c02 (http://rapidfire.sci.gsfc.nasa.gov/imagery/subsets/?subset=Arctic_r05c02.2013224.terra.367.1km) image.  8)

At any rate, we'll know in a few more hours, as that tile fills in for Aug 13/2013 (http://rapidfire.sci.gsfc.nasa.gov/imagery/subsets/?subset=Arctic_r05c02.2013225.terra.367.1km). Hopefully the cloud moves on.  ;)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 13, 2013, 11:41:20 AM
Beaufort is the region of the day, showing a rather large extent increase with a level area. As the image shows, the increase happens in a low concentration area. Perhaps the northern winds have caused some melt pool freeze: melt pools affect the ASI algorithm just as all algorithms.
Hi Wipneus,

I think there is a possibility that the change in sea ice concentration in the Beaufort sea on Aug 12/2013 is an artifact of clouds obscuring the sensor.


I think so too (that it is possible), although the effect may be caused by water vapor that comes with the clouds.

IJIS and NSIDC, not using the 89GHz channels, have less problems with clouds and vapor. IJIS reports a "normal" extent decline today. For NSIDC we can have a look at the regional split when it publishes its concentration data.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 14, 2013, 08:23:07 AM
Update 20130813.

Extent: -111k7 (+1075k vs 2012)
Area: -30k7 (+887k vs 2012)

Whatever caused the Beaufort bump yesterday, it is over with a huge drop in extent for that region. The CAB reverses the trend of the last few days, now we see a (moderate) extent drop and a bigger area rise, nothing to indicate in these numbers that the Big Drop is near. ESS declines further, today even the Greenland sea must be mentioned for a big decline. I haven't noticed any increased transport through the Fram Strait in contrast with expectations from some cyclone watchers.

 
You will find the updated graphs in the top post (https://forum.arctic-sea-ice.net/index.php/topic,382.0.html)

The details (in 1000 km2):


Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                  -13.8                   -18.3                     3.7
               Kara Sea             Barents Sea           Greenland Sea
                   -4.9                     0.2                   -21.9
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                    0.4                     0.0                    -0.6
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   -9.6                   -43.6                    -3.1
             Bering Sea          Sea of Okhotsk            Total Extent
                    0.0                     0.0                  -111.7

Area:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   26.7                    -2.2                    -5.0
               Kara Sea             Barents Sea           Greenland Sea
                    0.9                     0.1                   -19.0
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                    1.5                     0.0                     1.6
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                  -29.8                    -1.3                    -4.3
             Bering Sea          Sea of Okhotsk              Total Area
                    0.0                     0.0                   -30.7

Title: Re: Home brew AMSR2 extent & area calculation
Post by: Artful Dodger on August 14, 2013, 08:27:56 AM
It's cloud illusions I recall...  ;)

Joni Mitchell - Both Sides Now (With Lyrics) (http://www.youtube.com/watch?v=v9j_j-cUwKc#)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 14, 2013, 08:45:14 AM
Region of the day is the Canadian Archipelago. The NW passage, southern route, can now open any day. Only a small 30% concentration ice field in the Parry channel is blocking it up.
In the Nares Strait most ice is melting in situ. The PII-2012 iceberg is now separated and seems to have moved, if that is that possible ?????

(image attached, log in to see)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 14, 2013, 08:53:02 AM
Color coded concentration map of the same region.

(need to be logged in to see)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: TerryM on August 14, 2013, 09:34:46 AM
Wipneus
I can't see anything through the clouds but winds are low at Han Island and only 14m/s at Littleton Island. Tide is at it's weak point so I can't imagine that PII2012-A-1 is on the move.
Terry


Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 14, 2013, 09:42:37 AM
I think I can see it on NASA world view,  the true color view. See if I can make a reasonable image.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 14, 2013, 09:54:44 AM
Attached are the screen shots. Do you agree?
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Jim Hunt on August 14, 2013, 12:34:36 PM
I have double checked Wipneus, and I agree with you. It hasn't merely rotated a little, it's moved quite a distance. I now await today's Worldview image (http://earthdata.nasa.gov/labs/worldview/index.html?map=-702621.190435,-1143884.349154,-341149.190435,-902220.349154&products=baselayers,MODIS_Aqua_CorrectedReflectance_TrueColor~overlays,arctic_graticule_3413,arctic_coastlines_3413&time=2013-08-14&switch=arctic) with much interest!
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Yuha on August 14, 2013, 12:42:58 PM
A small piece is still stuck at the same place but the rest of it is now loose:
https://forum.arctic-sea-ice.net/index.php/topic,176.msg12426.html#msg12426 (https://forum.arctic-sea-ice.net/index.php/topic,176.msg12426.html#msg12426)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: TerryM on August 14, 2013, 03:38:51 PM
Wipneus


Our boy is on the move - wonderful catch!


I'll be following along on the Nares thread.
Terry
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 15, 2013, 08:22:39 AM
Update 20130814.

Extent: -2k2 (+1142k vs 2012)
Area: +9k3 (+1030k vs 2012)

It is soo quit up there. Kara is continuing its decline, CAA has a large uptick in area.
 
You will find the updated graphs in the top post (https://forum.arctic-sea-ice.net/index.php/topic,382.0.html)

The details (in 1000 km2):


Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   -4.0                    -0.8                    -2.5
               Kara Sea             Barents Sea           Greenland Sea
                  -10.8                     0.1                     9.9
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -0.1                     0.0                    -3.2
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                    6.9                     2.6                    -0.4
             Bering Sea          Sea of Okhotsk            Total Extent
                    0.0                     0.0                    -2.2

Area:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   -4.1                     2.0                    -1.4
               Kara Sea             Barents Sea           Greenland Sea
                  -12.0                     0.0                    14.0
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -0.3                     0.0                    -3.5
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   26.9                    -9.6                    -2.7
             Bering Sea          Sea of Okhotsk              Total Area
                    0.0                     0.0                     9.3

Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 15, 2013, 08:39:58 AM
Most of the melting is in the ice margin  of the CAB behind Severnaya Zemlya and Fransz Josef land, and the Kara sea of course. In the low concentration ice in the interior ever larger polynyas extent, but also close.

(log in to see attached image)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 15, 2013, 08:44:48 AM
And the color code concentration map of that region.

(log in to see)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 15, 2013, 10:53:38 AM
Extra close-up of Severnaya Zemlya. Nobody said "torch" here, but looking at the ice, warm winds are coming from Russia. It also looks like the North (East) passage might open first around the islands, and not along the continent. If that is possible.

(attached image, log in to see)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 16, 2013, 08:25:27 AM
Update 20130815.

Extent: -36k1 (+1199k vs 2012)
Area: -82k6 (+1017k vs 2012)

CAA has a very big drop today, in extent but especially in area. CAA has had some large swings lately, so it may not mean as big at it appears. Also the CAB has a large extent loss, compared with the last few days. Beaufort has a big uptick, as the remainder of the ice is all of low concentration that is to be expected: near the cut off of 15% a small concentration change has a large influence on the calculated extent.
 
You will find the updated graphs in the top post (https://forum.arctic-sea-ice.net/index.php/topic,382.0.html)

The details (in 1000 km2):


Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                  -20.1                    -6.8                    -8.8
               Kara Sea             Barents Sea           Greenland Sea
                    2.7                    -0.2                     4.9
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                    1.3                     0.0                    -0.8
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                  -33.1                    26.5                    -1.8
             Bering Sea          Sea of Okhotsk            Total Extent
                    0.0                     0.0                   -36.1

Area:
           Arctic Basin       East Siberian Sea              Laptev Sea
                  -18.6                   -14.2                    -8.8
               Kara Sea             Barents Sea           Greenland Sea
                    4.7                    -0.1                     0.7
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                    0.8                     0.0                    -0.1
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                  -60.0                    19.5                    -6.6
             Bering Sea          Sea of Okhotsk              Total Area
                    0.0                     0.0                   -82.6

Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 16, 2013, 08:40:02 AM
The Canadian Archipelago is today's region and I think we can declare the NW passage (southern route) open, at least for ice watchers.

(see this after logging in)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 16, 2013, 08:51:04 AM
And the color coded concentration map of the region. I took the "raw" version this time where the coastal phantom ice has not been removed. This makes sure the passage is not opened by my ice-clean-up algorithm.

(attached, log in to see)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 17, 2013, 08:29:21 AM
Waiting for the sea ice concentration data from Uni Hamburg....
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Frivolousz21 on August 17, 2013, 09:31:45 AM
with the big HP setting up I think there is a good chance we see you're his-red home brew have some big polyannas.

Hopefully Jaxa is ready to supplement AMSR2 data for 85N.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 18, 2013, 08:20:21 AM
Waiting for the sea ice concentration data from Uni Hamburg....

Nothing has changed so far, still waiting..
Title: Re: Home brew AMSR2 extent & area calculation
Post by: LarsBoelen on August 18, 2013, 06:13:15 PM
...and so the question is, what are TPTB witholding? What do they know that they do not want us to see? Is the Bilderberg group meeting in secret to come up with an explanation.

Did Santa drown? If they don't show us the pictures, we will row there ourselves to check!
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Jim Hunt on August 18, 2013, 06:38:31 PM
What are TPTB witholding? Did Santa drown? If they don't show us the pictures, we will row there ourselves to check!

No need to row Lars. Nothing for the 16th still, but most of the 17th now seems to be available. Lots more blue than on the 15th it seems:

Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 18, 2013, 07:20:17 PM
Update for 20130817.

As Jim showed, the data for 20130816 is missing completely and only some is there for 20130817. My program fills in the missing parts for 20130817, but the data should be looked upon with some caution.

The following changes are for TWO days:

Extent: -138k0 (+1090k vs 2012)
Area: -42k7 (+934k vs 2012)

You will find the updated graphs in the top post (https://forum.arctic-sea-ice.net/index.php/topic,382.0.html)

The details (in 1000 km2):


Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                  -67.3                   -19.8                     2.7
               Kara Sea             Barents Sea           Greenland Sea
                   -3.8                     0.0                     0.8
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -2.0                     0.0                    -7.3
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                  -49.2                     6.4                     1.5
             Bering Sea          Sea of Okhotsk            Total Extent
                    0.0                     0.0                  -138.0

Area:
           Arctic Basin       East Siberian Sea              Laptev Sea
                  -28.0                   -11.2                     6.9
               Kara Sea             Barents Sea           Greenland Sea
                    1.0                     0.0                    12.2
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -1.3                     0.0                    -3.7
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                  -20.7                     1.8                     0.4
             Bering Sea          Sea of Okhotsk              Total Area
                    0.0                     0.0                   -42.7
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 18, 2013, 07:28:58 PM
The Atlantic section of the CAB seems to be finally doing what was anticipated for weeks now and a huge polynya has formed.
NE passage is still not open.

(log in to see attached image)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 18, 2013, 07:30:36 PM
And the color coded concentration map.

(log in to see)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 19, 2013, 08:21:19 AM
Update 20130818.

Extent: +36k3 (+1245k vs 2012)
Area: +151k0 (+1186k vs 2012)

Big upticks, especially area. And it is mostly the CAB, Greenland sea has an uptick, hardly an indication that Fram transport is restarting.

 
You will find the updated graphs in the top post (https://forum.arctic-sea-ice.net/index.php/topic,382.0.html)

The details (in 1000 km2):


Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   10.6                    -1.9                     2.1
               Kara Sea             Barents Sea           Greenland Sea
                   -0.7                     0.3                    15.4
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -1.7                     0.0                     0.0
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                    6.2                     2.1                     4.0
             Bering Sea          Sea of Okhotsk            Total Extent
                    0.0                     0.0                    36.3

Area:
           Arctic Basin       East Siberian Sea              Laptev Sea
                  120.1                   -17.3                     5.5
               Kara Sea             Barents Sea           Greenland Sea
                   -3.1                     0.2                    11.0
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -1.1                     0.0                    -0.2
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   16.4                    17.8                     1.6
             Bering Sea          Sea of Okhotsk              Total Area
                    0.0                     0.0                   151.0

Title: Re: Home brew AMSR2 extent & area calculation
Post by: Frivolousz21 on August 19, 2013, 08:26:15 AM
What level of the atmosphere is the most cloud contamination.

It clears out a bit and we see how bad it is.  It clouds up or fog or something and the concentration goes up a ton.



(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FamDvFb9.jpg&hash=78e6a282307c557e46056972649fc47e)


(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2F5l7DpBT.jpg&hash=6c06a15b10e29063cfab583799e5a0fc)

Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 19, 2013, 08:32:28 AM
For thge region of the day, we go to the ESS and Laptev section. Activity is on the edges, a mixture of reds and blues giving only little nett change.

(log in to see attached image)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 19, 2013, 08:35:32 AM
And the color coded concentration map.

(also attached etc)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Frivolousz21 on August 19, 2013, 08:39:12 AM
According to the 6.25km Bremen AMSR2 we have seen no drop in extent and have gained extent.  Over the last 7-10 days.



(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FSphtXuU.png%3F1&hash=f53d9d6015c1e521280e193f6a3192b1)


Maybe it's the phantom ice in the SOO?  There is no way ice extent has gone up over the last week or even stayed even.  There is no where around the ice pack that would indicate that at all.


(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2F3xLg8YM.gif&hash=63332ad7c222bf37d51acd17ebb1a7cc)

Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 19, 2013, 08:55:45 AM
Quote
Maybe it's the phantom ice in the SOO?

There is an opposite phantom in the Atlantic, near st.Lawrence. Clearly their weather filters failed here.
Does it matter for extent/area? Maybe, maybe not. Depends on how they compute their extent and area.
In my AMSR2 calc these effects are filtered out.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 19, 2013, 09:01:21 AM
As an extra, the section between the NP and Greenland/Ellesmere.
A-Team on the ASIB is asking question about the two small areas with low concentration.
And is there such a big crack at the north coast of Greenland???
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 19, 2013, 09:04:26 AM
BTW, I am off for a small vacation with probably no internet. There will be no updates in the coming two days. Next update on Thursday if all goes well.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 19, 2013, 12:58:40 PM
I forgot to mention that all my source data for the 16th and 17th have been recovered and processed. Thank you guys for doing this in the weekend!
Title: Re: Home brew AMSR2 extent & area calculation
Post by: TerryM on August 19, 2013, 08:04:48 PM
Wipneus
Have a great couple of days away from the screen. I don't comment much on this thread but follow your graphs and calculations religiously.
If anyone deserves a little time off for good behavior it is you.
Terry
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Artful Dodger on August 20, 2013, 12:10:46 AM
If anyone deserves a little time off for good behavior it is you.
Ssh. Is he gone?  ::)
Epic Mickey OST: The Sorcerer's Apprentice (http://www.youtube.com/watch?v=ojCdXy2-yzA#)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 22, 2013, 08:30:25 AM
Update 20130821  :)

Because there was no report all numbers in this post are over the last three day. Divide by three to get the mean differences.

Extent: -169k7 (+1274k vs 2012)
Area: -114k9 (+1210k vs 2012)

Activity is mostly in the CAB. Not enough to clear the backlog with 2012, but a 400k until minimum should be possible. The ESS has some melt, but it has plenty of ice left where in 2012 it was now ice-free. Likewise, laptev and Beaufort seem to have stopped declining. Kara has enough melt to expect opening of the NE passage.
 
You will find the updated graphs in the top post (https://forum.arctic-sea-ice.net/index.php/topic,382.0.html)

The details (in 1000 km2):


Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                  -76.3                   -26.3                    -9.7
               Kara Sea             Barents Sea           Greenland Sea
                  -15.5                    -0.4                   -18.3
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                    6.7                     0.0                    -0.3
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                  -20.1                     3.6                   -13.1
             Bering Sea          Sea of Okhotsk            Total Extent
                    0.0                     0.0                  -169.7

Area:
           Arctic Basin       East Siberian Sea              Laptev Sea
                  -12.5                   -34.5                   -16.2
               Kara Sea             Barents Sea           Greenland Sea
                  -16.7                    -0.3                   -22.8
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                    3.8                     0.0                    -0.2
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                  -21.8                    15.7                    -9.5
             Bering Sea          Sea of Okhotsk              Total Area
                    0.0                     0.0                  -114.9
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 22, 2013, 08:51:02 AM
Also the extent-delta maps are over three days, just today. Here is the Atlantic section with the large polynya still staying and even growing. There is melt, compaction from the edge of the ice pack. The NE passage could open in days, either around the islands or near the continental coast.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 22, 2013, 08:59:00 AM
And the color coded concentration map (of 20130821). The pole hole is purple and quite invisible: no low concentration ice near the pole.

(attached image, log in to see)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Frivolousz21 on August 22, 2013, 09:39:28 AM
The clouds have prevented the true extent of the damage. 

Lots of ice bout to become open water

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FP3N8G2K.jpg%3F1&hash=d3b7b58838c72a81cf0562f616b1c127)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: danp on August 22, 2013, 05:16:59 PM
I mentioned over at http://neven1.typepad.com/blog/2013/08/asi-2013-update-7-cold-and-cloudy.html?cid=6a0133f03a1e37970b0192acb0cff5970d#comment-6a0133f03a1e37970b0192acb0cff5970d (http://neven1.typepad.com/blog/2013/08/asi-2013-update-7-cold-and-cloudy.html?cid=6a0133f03a1e37970b0192acb0cff5970d#comment-6a0133f03a1e37970b0192acb0cff5970d)
that I'm at a beta version on a new method for compositing any time length of MODIS images to select cloud-free scenes.  Here's a crop from the most recent 8 days, which have been cloudy enough to still challenge my algorithm:

(click to see full size, about 1700 pix across)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: werther on August 23, 2013, 12:38:27 AM
Dan P., hi,

I took the liberty to fit your collage in my CAD grid:

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi1036.photobucket.com%2Falbums%2Fa446%2Fhanver1%2FArctic%2520ice%25202013%2FArcticgridwithcollagelarge_zpsa05d0739.jpg&hash=5256202e76ce26c536eeed0550de9812)

I’m not sure yet what to do. Any digitized analysis consumes a lot of time. And I haven’t even finished my “grand” Greenland ice/snowline comparison 2009-2012 yet…

It seems best to wait until refreeze has started and begin analyzing what this season figures in October. It is tempting to start from your hard “cloud-clearing” work. At first glance, there are some limitations… like the ice boundary. As you chose cloudfree app. 100x100 km blocks from differing dates, the positions get “ jittered” (if I use that A-Team term in the right way?). Also, the resolution is less than the app. 4 Mb/16,8 Mpix MODIS tiles I copy.

Nevertheless, on this frame you’ll see my fat red line for the “uncompromized” 28 August mesh-pack on the left. The Pole is in a low concentration zone, tentatively positioned in a rather ‘wet’ inter-floe rubble pixel. Santa has his herd of reindeer scattered over a lot of small particles!

The high concentration zone lies about 40 km into the direction of Ellesmere Island. The “mesh-pack” boundary is way further, at 225 km from the Pole.
Last year, even at minimum, it stretched some 100 km from the Pole in the direction of Siberia…

The high concentration zone , about 180 km broad, is where the mesh-pack constantly disintegrates and feeds the debris in the immense, almost 2 mkm2 measuring splinter zone.
All that is left of the once majestic MYI summer ice pack is now a mere 500 km broad swath up to Ellesmere.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: danp on August 23, 2013, 01:04:42 AM
Hi Werther,

I was hoping a long-time ice-watcher like you would find this presentation useful.  I have considered processing all the way to the top MODIS resolutions (250m, compared with my 500m), so I will take that as a positive vote.  It would take a good deal longer and processing time is a bit long right now, but I haven't optimized much for that yet.  As far as my main constraint (download bandwidth) I already am downloading the appropriate data to do so; it is only channels 1 & 2 that have the top resolution, and the top resolution data (for all 37 channels!) is there in the swath downloads, so I could do what NASA does and resample the lower-resolution channels to match. 

I agree the blocked nature of the presentation means neighboring tiles can have discontinuities in ice position.  The typical dispersion between tiles in an 8-day composite might be about 4 days, and when I'm manually clear-image hunting I often wind up comparing MODIS images from that far apart anyway, so I'm already resigned to that resolving those kinds of time discontinuities when they are presented obviously.  In any case it is that is far less objectionable than the pixel-by-pixel smearing that NASA's composites have.  Of course I could easily go the other direction and process with larger tile sizes for a more coherent picture, but at a sacrifice of clearness, since I wouldn't be able to remove as many clouds.  NASA's ordinary rapid-response mosaics aren't trying to remove clouds, so they have a lot fewer objectionable seams (except at the pole) since their effective block size is usually pretty large.

It may well be that there are different optimal choices for different cloud conditions and compositing time lengths, but I do want to settle on something so I can start back-processing data from this year and previous years.

In any case this product is very much in an "alpha" or "beta" version, so any comments you have are appreciated! 
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Mari on August 23, 2013, 05:53:46 AM
danp,
I have been watching and studying for several months here and am venturing my first post to tell you that I am really excited about your composite project. I would love to see it at 250. I began studying sea ice last fall while enrolled as an undergrad painting major. I was getting a lot of flack for painting a landscape (boring, already been done...), so I decided for my next series I'd take my references from satellite and ariel images. My studio space was always open and it ended up that it was where most other students first learned anything about the arctic. I taped up a lot of print outs on what was happening then and it got a lot of interest. It is also pretty cool when the images are 4 feet across. When people see what the arctic looks like, they really are amazed. That's an opportunity then to begin to begin to educate them about it. I have since graduated and do not have studio space, but as soon as I can I will be back to painting sea ice again. Meanwhile I have gained such an education from reading the forum and following up with study. Many thanks to Espen and all of you.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 23, 2013, 08:28:43 AM
Extent: -53k7 (+1284k vs 2012)
Area: -91k0 (+1136k vs 2012)

The melt is continuing mostly in the CAB and ESS. Area decline in the CAB is even bigger, probably a "rebound" from the slow last few days.

Added to the extent, area and compaction graphs are the calculated values from Jaxa's AMSR2 concentration data. These (level 3) data are available in a 10km polar stergraphic grid. Jaxa uses a modified Bootstrap sea ice concentration algorithm, so it is interesting to compare with the ASI algorithm used by Uni Hamburg.
 
You will find the updated graphs in the top post (https://forum.arctic-sea-ice.net/index.php/topic,382.0.html)

The details (in 1000 km2):


Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                  -23.6                   -14.8                    -8.3
               Kara Sea             Barents Sea           Greenland Sea
                   -2.9                     0.0                    -1.8
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                    1.3                     0.0                    -1.5
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   -7.6                    -1.9                     7.3
             Bering Sea          Sea of Okhotsk            Total Extent
                    0.0                     0.0                   -53.7

Area:
           Arctic Basin       East Siberian Sea              Laptev Sea
                  -70.9                    -8.1                    -4.9
               Kara Sea             Barents Sea           Greenland Sea
                   -2.9                     0.0                    -3.9
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                    0.2                     0.0                    -1.6
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   -9.1                     1.7                     8.3
             Bering Sea          Sea of Okhotsk              Total Area
                    0.0                     0.0                   -91.0

Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 23, 2013, 08:41:33 AM
I keep looking at the Atlantic section. The polynya seems have moved to the east.

(image attached, log in to see)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 23, 2013, 08:42:46 AM
And the color coded concentration map.

(log in to see)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Artful Dodger on August 23, 2013, 09:34:22 AM
I have considered processing all the way to the top MODIS resolutions
<snip>
my main constraint (download bandwidth)
Hi Dan, great work!

Couldn't you use the 4 km 3-6-7 daily data to select the 250 m data to download? Then you'd only be downloading large files that you will actually use.

Thanks again for these outstanding derivatives.  :D
Title: Re: Home brew AMSR2 extent & area calculation
Post by: danp on August 23, 2013, 04:58:20 PM
Thanks Artful Dodger!

Couldn't you use the 4 km 3-6-7 daily data to select the 250 m data to download? Then you'd only be downloading large files that you will actually use.


I've thought of doing something like that, although my clear-swath algorithm requires a lot more data than just the 3-6-7.  In general the best data series for my purposes has turned out to be the level-2 MOD09 swaths.  These include *all* MODIS channels at their top resolutions, and there's no subsampled version.  The reason I chose this series was that the extra processing that the NASA land team does beyond the 1B files to remove haze, correct for sun angle and atmospheric reflection, and calculate absolute surface reflectance, was quite effective and beyond my ability to reproduce without tremendous work.  Even though those efforts aren't all well-optimized for the Arctic, they're a major help since the sun angle is always so low.

I've needed to use all of this good-quality data to assess my algorithm's selection abilities, as well for as a couple of other so-far unsuccessful projects.  Once everything about the method of producing this data is settled, I can reassess the ongoing downloads required, but for now it's an easy if inconvenient task.  I suppose I should have said the true bottleneck is my programming time :)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 24, 2013, 08:17:40 AM
Update 20130823.

Extent: -28k0 (+1241k vs 2012)
Area: +18k3 (+1154k vs 2012)

Slowing down, most of the little activity is CAB.
As a reminder, on the graphs you can follow the Bootstrap Jaxa AMSR2 extent and area. The calculation (from Jaxa L3 data) now includes both ascending and descending swaths. Not unlike the Windsat data, but much much smoother, without any averaging (AFAIK).

 
You will find the updated graphs in the top post (https://forum.arctic-sea-ice.net/index.php/topic,382.0.html)

The details (in 1000 km2):


Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                  -14.1                    -9.1                    -5.2
               Kara Sea             Barents Sea           Greenland Sea
                   -4.5                     0.0                    10.1
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -9.4                     0.0                     0.5
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   -0.8                     7.5                    -3.2
             Bering Sea          Sea of Okhotsk            Total Extent
                    0.0                     0.0                   -28.0

Area:
           Arctic Basin       East Siberian Sea              Laptev Sea
                    3.3                     3.8                    -2.8
               Kara Sea             Barents Sea           Greenland Sea
                   -3.5                     0.0                    13.8
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -6.3                     0.0                     1.1
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                    1.8                    12.7                    -5.5
             Bering Sea          Sea of Okhotsk              Total Area
                    0.0                     0.0                    18.3

Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 24, 2013, 08:26:27 AM
Still looking at the polar polynya's and watching it grow.

(attached image, log in to see)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 24, 2013, 08:27:45 AM
And the color coded concentration map.

(log in etc.)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 25, 2013, 08:21:56 AM
Today's update from Uni Hamburg - three hours earlier than usual - contains no data.

Hopefully it gets fixed soon.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 26, 2013, 08:07:45 AM
Update 20130825.

Extent: -29k3 (+1343k vs 2012)
Area: -64k7 (+1115k vs 2012)

An early update, data 20130824 was updated as well. The CAB is continuing its decline, today especially in area. The ice in the ESS is on the increase, other regions are relatively quit.
 
You will find the updated graphs in the top post (https://forum.arctic-sea-ice.net/index.php/topic,382.0.html)

The details (in 1000 km2):


Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                  -37.2                    12.7                   -11.1
               Kara Sea             Barents Sea           Greenland Sea
                    0.7                    -0.3                     7.8
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                    1.6                     0.0                    -0.7
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                    7.1                    -0.4                    -9.6
             Bering Sea          Sea of Okhotsk            Total Extent
                    0.0                     0.0                   -29.3

Area:
           Arctic Basin       East Siberian Sea              Laptev Sea
                  -89.6                    17.4                    -7.8
               Kara Sea             Barents Sea           Greenland Sea
                    0.7                    -0.2                    17.4
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                    1.2                     0.0                    -0.2
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   14.5                   -13.2                    -5.0
             Bering Sea          Sea of Okhotsk              Total Area
                    0.0                     0.0                   -64.7

Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 26, 2013, 08:18:55 AM
Today a large region of the day, the Siberian section of the CAB and large part of the Atlantic section. The polar polynya continues to grow. The ice edges are giving way on the Laptev/Kara side,  but grow on the ESS side. There is very little ice blocking the NE passage now.

(log in to see attached message)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 26, 2013, 08:20:43 AM
And the color coded concentration map.

(attached as well, log in)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: TerryM on August 26, 2013, 09:03:00 AM
Wipneus
I know this has been asked in the past, but do you think there is any chance that we'll see two separate ice packs this year. Winter is fast approaching so I suppose I'm relieved that this pattern wasn't in place 3 weeks ago when the sun was a little higher over the horizon.
At the moment it seems we're in a race with the inexorable chill that winter will bring.
Terry
Title: Re: Home brew AMSR2 extent & area calculation
Post by: jdallen on August 26, 2013, 09:19:38 AM
I think for all intents and purposes, we have at least three, as even though the are no separated by obvious open water, they are physically disconnected in ways the Mesh pack isn't. I wonder what effect this may have on ridging, and possible circulation?
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 26, 2013, 09:26:46 AM
Terry, you are giving my own thoughts words. I can only add that CAB extent declined in 2012 until late in September, if repeated then some 400-500k loss is still in the pipe line. 400k is also the difference between CAB-area and CAB-extent.

(https://sites.google.com/site/arctischepinguin/home/amsr2/grf/amsr2-extent-regional.png)
Title: Can you generate a map showing the seven-day change?
Post by: paulklem on August 26, 2013, 05:50:21 PM
The change over the last week in red/blue, could be interesting. The open areas are both growing and moving, so there should be a red rim, and on the other side of open water areas, a blue rim.

TIA.
Title: Re: Can you generate a map showing the seven-day change?
Post by: Wipneus on August 26, 2013, 07:07:17 PM
The change over the last week in red/blue, could be interesting. The open areas are both growing and moving, so there should be a red rim, and on the other side of open water areas, a blue rim.

TIA.

We have seen that pattern already this week. Here is the difference with a week ago.

(log in etc)
Title: Thanks. Very interesting image.
Post by: paulklem on August 26, 2013, 07:31:42 PM
The big polynya grew significantly, and doesn't have much of blue edge, indicating that side of the polynya melted out as the pack moved.  Also Looks like 80-100 km of ice edge retreat on the Barents sea side. This next two weeks should be very interesting.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Shared Humanity on August 26, 2013, 07:55:39 PM
Is the lack of blue in the low concentration areas in the CAB evidence of very little compaction?
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Bob Wallace on August 26, 2013, 08:01:39 PM
Seems like a one week comparison would be more useful than a one day comparison.  (Looking at your recent image post.)

Reserve the one day comparison for times at which something unusually strong might happen
Title: Re: Home brew AMSR2 extent & area calculation
Post by: jdallen on August 26, 2013, 08:39:45 PM
Is the lack of blue in the low concentration areas in the CAB evidence of very little compaction?

More like the practical impossibility of sorting out the myriad of small changes manually, I think...
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 27, 2013, 08:17:50 AM
Update 20130826.

Extent: -10k9 (+1375k vs 2012)
Area: -21k5 (+1196k vs 2012)

CAB has a bit slower day, especially in extent. Most of the decline to day in CAA, folowed by Laptev and ESS.


 
You will find the updated graphs in the top post (https://forum.arctic-sea-ice.net/index.php/topic,382.0.html)

The details (in 1000 km2):


Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   -7.3                    -7.7                    -9.0
               Kara Sea             Barents Sea           Greenland Sea
                    1.9                     0.1                    15.1
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                    5.4                     0.0                     0.3
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                  -14.6                     7.6                    -2.5
             Bering Sea          Sea of Okhotsk            Total Extent
                    0.0                     0.0                   -10.9

Area:
           Arctic Basin       East Siberian Sea              Laptev Sea
                  -18.2                    -8.5                    -7.6
               Kara Sea             Barents Sea           Greenland Sea
                   -0.4                     0.1                    10.9
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                    3.1                     0.0                     0.1
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   -9.5                     8.9                    -0.2
             Bering Sea          Sea of Okhotsk              Total Area
                    0.0                     0.0                   -21.5

Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 27, 2013, 08:38:25 AM
As this thread is partly following the day-to-day development of the arctic sea ice coverage during the 2013 melt season, here I zoom in on the daily change of the Polar Polynya: it is still growing.
It is now up to 50 pixels wide: more than 150km.

(log in to see attached image)

Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 27, 2013, 08:54:56 AM
And because it is high time we look elsewhere as well, here is the situation in the east. Here it is more a mix of reds and blues->little net change. A large ice island, separated from the pack is about to disappear.

(images attached, log in to see them)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 27, 2013, 09:22:00 AM
Seems like a one week comparison would be more useful than a one day comparison.  (Looking at your recent image post.)

Reserve the one day comparison for times at which something unusually strong might happen

Bob,
A two-week comparison is part of Neven's two weekly overview on ASIB.
The daily comparison are part of the daily numbers, I would not like to see that change.

Anyway, when the season is over (first October), I intend to stop for some reflection,  rehauls of  some algorithms and software rewrites. The goal for 2014 is some automated way of presenting near-real-time regional area and extent from as many sources as I can possibly find.
The best way to present them is part of that and suggestions are very welcome.


Title: Re: Home brew AMSR2 extent & area calculation
Post by: TeaPotty on August 27, 2013, 02:26:55 PM
The goal for 2014 is some automated way of presenting near-real-time regional area and extent from as many sources as I can possibly find.
The best way to present them is part of that and suggestions are very welcome.

That sounds great Wipneus   :D
Title: Re: Home brew AMSR2 extent & area calculation
Post by: helorime on August 27, 2013, 03:49:57 PM
I must say that if I am awake late enough, or wake up in the middle of the night, I immediately go to this forum to see if Wipneus's home brew calculations and maps are up.  They are great!  Good work, and I will look forward to enhanced ones next year.   :)

note:  I tend to go back and edit my typos if I see them, randomly.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Neven on August 27, 2013, 08:34:23 PM
I will also try to give your work more of the attention it deserves, Wipneus. Hopefully I have more time and an idea how to use your stuff by then. Or maybe we can think up something together.

This thread is my favourite on the forum.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: LarsBoelen on August 27, 2013, 10:18:32 PM
Wipneus,

What astonishes me is this. The detailed color coded maps appear to be almost binairy : ice is either purple or red, or open water (blue). So it seems that once the ice concentration comes below 85% it crashes down to 30% and then dissolves. You would expect large amounts of 60-50-40% ice, but that category seems almost missing. Is this an artifact of your moddeling, or is there a physical cause for this behaviour?

Lars
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Richard Rathbone on August 28, 2013, 07:41:14 AM
Wipneus,

What astonishes me is this. The detailed color coded maps appear to be almost binairy : ice is either purple or red, or open water (blue). So it seems that once the ice concentration comes below 85% it crashes down to 30% and then dissolves. You would expect large amounts of 60-50-40% ice, but that category seems almost missing. Is this an artifact of your moddeling, or is there a physical cause for this behaviour?

Lars

I don't see a lot at 30% either.

One reason to expect not a lot of change then a crash, is that the ice is fairly uniform in thickness.   As it melts it thins, but the area doesn't change much until the thickness is close to zero, and then it doesn't take much more melting for it all to go.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 28, 2013, 08:02:24 AM
Update 20130827.

Extent: -36k2 (+1347k vs 2012)
Area: -43k4 (+1228k vs 2012)

CAB, ESS and Laptev cause the decline in extent. The CAB is the only one that is declining in area as well.
 
You will find the updated graphs in the top post (https://forum.arctic-sea-ice.net/index.php/topic,382.0.html)

The details (in 1000 km2):


Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                  -16.5                   -13.7                   -13.8
               Kara Sea             Barents Sea           Greenland Sea
                   -0.7                     0.3                    -0.3
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                    1.4                     0.0                    -1.8
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                    4.4                     0.9                     3.7
             Bering Sea          Sea of Okhotsk            Total Extent
                    0.0                     0.0                   -36.2

Area:
           Arctic Basin       East Siberian Sea              Laptev Sea
                  -39.4                    -0.3                    -9.0
               Kara Sea             Barents Sea           Greenland Sea
                    1.3                     0.3                    -1.3
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                    1.6                     0.0                    -1.2
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                    5.6                    -3.8                     2.9
             Bering Sea          Sea of Okhotsk              Total Area
                    0.0                     0.0                   -43.4

Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 28, 2013, 08:30:53 AM
Take a day off from watching the polar polynya (it is unchanged today), focus on Laptev and the remnants of the Kara sea ice. The SE winds cause retreat of the ice edge over a long stretch. The NE   route seems to be passable via the Vilkitsky Strait, although on the surface considerable ice is reported (https://forum.arctic-sea-ice.net/index.php/topic,549.0.html (https://forum.arctic-sea-ice.net/index.php/topic,549.0.html))

(image is attached, log in to see)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 28, 2013, 08:37:50 AM
And the color coded concentration map of the region.

(log in etc.)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 28, 2013, 08:48:20 AM
Wipneus,

What astonishes me is this. The detailed color coded maps appear to be almost binairy : ice is either purple or red, or open water (blue). So it seems that once the ice concentration comes below 85% it crashes down to 30% and then dissolves. You would expect large amounts of 60-50-40% ice, but that category seems almost missing. Is this an artifact of your moddeling, or is there a physical cause for this behaviour?

Lars, there is no modelling from me involved here. All that is done here is coloring the pixels by the ice concentration (as calculated by the people at Hamburg University).

And yes, good spotting. It is part of the reason that I choose this scale with such uniform changing with concentration. Compare for instance with Uni Bremen's map.

Nice when people are paying attention.

And no, I don't have a good answer. Keep in mind that the Artist Sea Ice (ASI) algorithm is specially sensitive to water (vapor and liquid cloud) in the atmosphere, compared with other calculations. Clouds seem to increase the purples somewhat is my impression.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Frivolousz21 on August 28, 2013, 09:17:39 AM

AMSR2-Hamburg-3.125km-Enhanced
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FwUb5qbB.jpg%3F3&hash=9a11f3b087f797c297a207ad716c70a9)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: pearscot on August 28, 2013, 04:37:53 PM
Wow, that picture really shows a lot (assuming it's pretty accurate).  I know we are well above 2012 and won't touch that, but the ice really seems to be quite strained.  I wonder if the large and broken flow will fill up quickly once the refreeze begins shortly.  Either way, it's impressive to see the ice sheet almost ripped in two.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: wanderer on August 28, 2013, 04:56:19 PM
I know it's pretty late in the melt season, but is it possible that it could break in two?
The difference to last week seems huge!
Title: Re: Home brew AMSR2 extent & area calculation
Post by: werther on August 28, 2013, 06:01:55 PM
Hi Wanderer,

I find the metaphor you chose, "break in two", rather funny. What comes to my mind is more like "shattered into pieces" over 40% of its extent.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: wanderer on August 28, 2013, 07:13:55 PM
Sure, I ment "two parts of shattered pieces"  ;-)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: dbostrom on August 29, 2013, 02:31:35 AM
The sea ice diaspora is something new, isn't it?
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Vergent on August 29, 2013, 06:28:17 AM

AMSR2-Hamburg-3.125km-Enhanced
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FwUb5qbB.jpg%3F3&hash=9a11f3b087f797c297a207ad716c70a9)

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2F1ow9krc.png&hash=16ec796d317653f08d243bd89c033ecc)

Vergent
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 29, 2013, 08:11:06 AM
Update 20130828.

Extent: -43k2 (+1338k vs 2012)
Area: -37k2 (+1206k vs 2012)

The ice CAB keeps declining strongly, in 2012 the decline in area had slowed down by this date (compaction did cause continuing decline of extent). Laptev, yesterday region of the day, continues the decline and Beaufort, long time no significant changes, records a lower ice cover.
 
You will find the updated graphs in the top post (https://forum.arctic-sea-ice.net/index.php/topic,382.0.html)

The details (in 1000 km2):


Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                  -28.6                     2.5                   -10.3
               Kara Sea             Barents Sea           Greenland Sea
                   -4.7                    -0.1                    -0.9
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -2.7                     0.0                     0.9
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   10.7                   -13.0                     3.0
             Bering Sea          Sea of Okhotsk            Total Extent
                   -0.1                     0.0                   -43.2

Area:
           Arctic Basin       East Siberian Sea              Laptev Sea
                  -30.0                     4.0                   -10.5
               Kara Sea             Barents Sea           Greenland Sea
                   -4.6                    -0.1                     1.4
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -2.0                     0.0                     0.8
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   10.2                    -8.1                     1.7
             Bering Sea          Sea of Okhotsk              Total Area
                    0.0                     0.0                   -37.2

Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 29, 2013, 08:21:04 AM
The Atlantic section is where CAB is loosing extent, all along the Kara, Barents and Greenland sea edges. The Polar Polynya is both getting smaller as it moves north.

(log in to see attached image)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 29, 2013, 08:22:29 AM
And the color coded concentration map.

(log in etc.)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 30, 2013, 08:02:13 AM
Update 20130829.

Extent: -44k7 (+1374k vs 2012)
Area: +88k6 (+1373k vs 2012)

A HUGE increase in CAB area, freezing? snowfall?, clouds? Nothing similar visible in other regions, Laptev continues the decline, and also CAB extent has a moderate decline.

 
You will find the updated graphs in the top post (https://forum.arctic-sea-ice.net/index.php/topic,382.0.html)

The details (in 1000 km2):


Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                  -13.5                    -2.9                   -18.0
               Kara Sea             Barents Sea           Greenland Sea
                   -0.1                     0.1                    -0.2
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -0.2                     0.0                     0.4
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                    2.7                    -7.0                    -6.0
             Bering Sea          Sea of Okhotsk            Total Extent
                    0.0                     0.0                   -44.7

Area:
           Arctic Basin       East Siberian Sea              Laptev Sea
                  109.6                     1.8                   -15.6
               Kara Sea             Barents Sea           Greenland Sea
                    2.1                     0.1                    -4.7
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                    0.3                     0.0                     0.4
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   -2.2                     0.4                    -3.7
             Bering Sea          Sea of Okhotsk              Total Area
                    0.0                     0.0                    88.6

Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 30, 2013, 08:15:50 AM
This the section of the CAB where the actions is. The Polar Polynya has shrunk considerably, further the red and blues are balancing with reds dominant in the Pacific section. Plenty of melt still on the fringes, especially Laptev.

(attached image are for those that logged in)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 30, 2013, 08:22:01 AM
And the color coded concentration map.

(log in etc)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Richard Rathbone on August 30, 2013, 08:24:50 AM
I suspect your pole hole calculation is liable to reporting big swings in area from small rearrangements in that near pole polynya. I could see the concentration in there bouncing around by 10% with no actual area change, just the polynya shifting slightly. How much area is 10% of the pole hole?
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Lennart van der Linde on August 30, 2013, 08:36:24 AM
"A HUGE increase in CAB area, freezing? snowfall?, clouds?"

Or maybe (also) compaction?
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 30, 2013, 09:19:22 AM
I suspect your pole hole calculation is liable to reporting big swings in area from small rearrangements in that near pole polynya. I could see the concentration in there bouncing around by 10% with no actual area change, just the polynya shifting slightly. How much area is 10% of the pole hole?

Richard: the pole hole is 56 pixels across, about 25000 km2.

Attached a blow-up of the pole hole, and the "ring" from which I calculate average area.

Note that extent in the pole hole is assumed to be 100%. I did not reckon with the possibility of polynya's so near the pole this season!
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 30, 2013, 09:21:53 AM
"A HUGE increase in CAB area, freezing? snowfall?, clouds?"

Or maybe (also) compaction?

Compaction should lower extent and leave area unchanged (or lower less than extent).
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Lennart van der Linde on August 30, 2013, 09:31:15 AM
How about compaction possibly pushing areas below 15% concentration above that level? Or is that not relevant in your/this calculation? I'm not very technical, so forgive me if this not such a smart question :)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Vergent on August 30, 2013, 09:47:10 AM
wipneus,

refreeze in the CAB is not new news. at this time of year. The issue is not the parallel melt. The issue is the serial melt. The actual MYI will be the surviving ice from all areas. They will not melt out at the same time. The summation of the regional graph minimums is the surviving MYI, not the summation of the least summation of the total current ice. The cab will freeze before the peripheral melts. The issue is the minimum. Last year the  interior was refreezing while the exterior was still thawing. I think think the actual minimum is not simultaneous,it is serial.

Vergent
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 30, 2013, 09:49:50 AM
How about compaction possibly pushing areas below 15% concentration above that level? Or is that not relevant in your/this calculation? I'm not very technical, so forgive me if this not such a smart question :)

Compacting ice in a gridcell from 14.999% to 15.001% would increase the area in this cell from 0->15%. The cell's extent at the same time goes from 0%->100%.

So from this effect you would expect the extent to make large swings, not reflected in area. We have seen this this year when Hudson melted out and in Beaufort. The NSIDC numbers are plagued by noise from low concentration fake ice swinging around the 15% cutoff.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 30, 2013, 10:20:23 AM
Vergent,

I probably was not clear. It is not unexpected to see signs of refreezing at this time. I am surprised by the large decrease yesterday and the today's huge increase.
Or do you have an explanation why refreezing does not start gradually but must begin with a bang?
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Vergent on August 30, 2013, 10:26:00 AM
Okay,

The difference between serial melt and parallel melt is the difference between the time of month for the different minimums on the CT graphics. They do not happen at the same times. So, in the fall, The CAB is refreezing, big time, but the Siberian arctic shelf is melting. So what is the net result? It depends on what result You Want  If you want a low number, Pick the serial melt, you get it. You want a big number, pick the parallel, you get it. Okay, choose your side. Now open the winners box. Did you win?

Vergent
Title: Re: Home brew AMSR2 extent & area calculation
Post by: slow wing on August 30, 2013, 11:55:37 AM
Wipneus,

   On looking at MODIS Worldview, there appears to be a thin skin of new ice now over much of the exposed water near the Pole and on the Pacific side. When zoomed right in, little cracks that are even darker can be seen on the already dark regions between the floes: polynya within polynya! So that appears to show that the regions between the floes are mostly thin ice rather than completely exposed water.

This region is where some blue patches appear in your difference map, indicating ice where there was none before.

 So maybe that provides some explanation for increased area but not increased extent: new thin ice on areas that already had floes and so the cells were already above the 15% threshold you use in the extent calculation.

Does that explanation hang together given the observations and understanding of the processes that people have?
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Richard Rathbone on August 30, 2013, 12:34:45 PM
Throw in a bit of compaction (the extent has actually dropped) and that works.

Wipneus,

That's only a possible bounce of 2-4 (I'm not sure I'm picking the right shades off the scales for it) from the polynya moving yesterday and I doubt you'll ever be more than 10 out from a polynya in the area biassing the assumed concentration for the pole. If you are going to revise anything, I'd revise the extent calculation to be based on extent in the surrounding ring too. A big melt season and you could end up with 0 concentration and 100% extent in that hole.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 30, 2013, 01:45:08 PM
If you are going to revise anything, I'd revise the extent calculation to be based on extent in the surrounding ring too.

Of course, but that can wait until the season is completely over. There are several other similar things that I'd like to do.

Quote

A big melt season and you could end up with 0 concentration and 100% extent in that hole.

If average concentration goes now below 15%, the extent of the hole will drop from 100% to 0%. Something I expect to handle better by next year.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 31, 2013, 08:13:57 AM
Update 20130830.

Extent: -27k8 (NA vs 2012)
Area: +43k3 (NA vs 2012)

(no available data in 2012)

CAB sea ice area keeps increasing strongly but holds down the net extent. Melting is continuing in the CAA and Laptev.
Jaxa's AMSR2 L3 sea ice concentration data  for 20130829 is now in, the increase in CAB area is moderate: +16k5, compared with +109k6 for UH AMSR2. It seems the algorithms differ here. It is all in the graphs.
 
You will find the updated graphs in the top post (https://forum.arctic-sea-ice.net/index.php/topic,382.0.html)

The details (in 1000 km2):


Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                    5.2                     4.1                   -12.9
               Kara Sea             Barents Sea           Greenland Sea
                    2.1                     0.0                     1.7
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                    0.9                     0.0                    -1.5
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                  -18.9                    -1.2                    -7.3
             Bering Sea          Sea of Okhotsk            Total Extent
                    0.0                     0.0                   -27.8

Area:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   81.0                     3.3                   -12.0
               Kara Sea             Barents Sea           Greenland Sea
                   -0.1                    -0.1                    -8.4
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                    1.6                     0.0                    -1.4
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                  -14.7                    -1.8                    -3.9
             Bering Sea          Sea of Okhotsk              Total Area
                    0.0                     0.0                    43.3

Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 31, 2013, 08:34:37 AM
Not much changed in the CAB, we can have a look again at the situation in the CAA. Sometime ago, the southern route of the NW passage was "open" (by satellite microwave sensors) fro a short while. Ice have been moving around, and the straits got blocked again. Looking at the ice in the Parry channel, it looks as some of the ice was pulled in from the north.

(log in to see attached image)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 31, 2013, 08:38:57 AM
And the color coded concentration map.

(log in etc)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 31, 2013, 08:54:56 AM
And an (attached) animation.

Title: Re: Home brew AMSR2 extent & area calculation
Post by: Richard Rathbone on August 31, 2013, 09:04:10 AM
Looking at the graphs, it seems JAXA normally has a slightly lower concentration than UH, but that UH is prone to occasional low concentration episodes. The past couple of days look like the upswing at the end of one of those dips. Some of the UH dips coincide with CT melt pond blips so are probably caused by that, but I don't have any idea what the one just ending would have been due to. 
Title: Re: Home brew AMSR2 extent & area calculation
Post by: TerryM on August 31, 2013, 09:13:25 AM
Watching the pole with MODIS & WorldView it seems as though whenever the clouds blow away another area is revealed as predominantly open water. Is it possible that much of our CAB figures are based on fog and clouds?
Terry
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Neven on August 31, 2013, 09:17:05 AM
And an (attached) animation.

Interesting to see some MYI transport into the CAA, even though this year doesn't come close to previous melting seasons.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Frivolousz21 on August 31, 2013, 10:10:44 AM
Terry, Clouds effect the channel 89, 91, and 85GHZ more than the lower channels I believe.

But I think atmosphere effects those channels more than the higher ones.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: johnm33 on August 31, 2013, 10:48:10 AM
Looking at the animation, where one would expect logjams of MYI there are none. Instead it's possible to see it as warm water entering from the north at depth unable to pass through, building up, and melting the ice from below.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on August 31, 2013, 04:31:16 PM
Perhaps the following graph helps. These large swing are visible only in the CAB, so lets plot this for the different sea ice concentrations that I calculated area from.

The uptick in area occurs only in the UH products, it may well revert downwards again.

There are other interesting differences between the different algorithms:

- The June "cliff" hardly visible in Jaxa Bootstrap;
- A July "depression" only visible in NSIDC's NASA TEAM (and therefore in CT area);
- the exaggerated loss of NSIDC (thus CT) was already well known.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on September 01, 2013, 08:04:48 AM
Update 20130831.

Extent: -3k5 (+1333k vs 2012)
Area: -8k7 (+1369k vs 2012)

Net the melt has come to a halt. On regional scale ESS and Laptev continue to decline, but on the other side the CAA and Beaufort increased.  At least the largeincrease in CAB area has stopped, and reversed a little bit.

 
You will find the updated graphs in the top post (https://forum.arctic-sea-ice.net/index.php/topic,382.0.html)

The details (in 1000 km2):


Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   -2.4                    -8.4                   -10.7
               Kara Sea             Barents Sea           Greenland Sea
                   -2.2                     0.1                    -0.2
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                    0.7                     0.0                    -2.4
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   12.1                     7.9                     2.1
             Bering Sea          Sea of Okhotsk            Total Extent
                    0.0                     0.0                    -3.5

Area:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   -9.9                    -4.3                    -7.8
               Kara Sea             Barents Sea           Greenland Sea
                   -3.5                     0.1                    -1.6
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                    0.5                     0.0                    -1.2
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   10.1                     7.5                     1.5
             Bering Sea          Sea of Okhotsk              Total Area
                    0.0                     0.0                    -8.7

Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on September 01, 2013, 08:23:55 AM
The Polar Polynya that was shrinking seriously a few days ago, seem to hold on even grows a bit, while moving westward.

(image attached, log in to see)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on September 01, 2013, 08:26:05 AM
About the same area, now as color coded concentration map.

(log in to see)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Frivolousz21 on September 01, 2013, 09:25:48 AM
Euro is a bone crusher

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2F3kh4Hbu.gif&hash=af2875d4459e8c4397fccc8924265354)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: jdallen on September 01, 2013, 09:37:02 AM
That looks like another serious blow, looking at the gradient.  Doubt it will do much more than grind up the ice more.  Might shove a slug out the Fram.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Frivolousz21 on September 01, 2013, 09:46:40 AM
It will cause big compaction in the Chukchi-Laptev regions.

It's about as bad as it can be for this time of year.

Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on September 02, 2013, 03:35:03 PM
Update 20130901.

Extent: -7k4 (+1293k vs 2012)
Area: -14k9 (+1394k vs 2012)

Same situation as yesterday: overall slow with some melt on the Siberian side (ESS, Laptev, Kara) and some increase in the CAA and Beaufort. The CAB has loses area, but no net extent loss.
 
You will find the updated graphs in the top post (https://forum.arctic-sea-ice.net/index.php/topic,382.0.html)

The details (in 1000 km2):


Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   -0.6                   -10.0                    -6.8
               Kara Sea             Barents Sea           Greenland Sea
                   -3.3                     0.2                     3.2
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -5.1                     0.0                    -0.5
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   12.6                     4.8                    -1.8
             Bering Sea          Sea of Okhotsk            Total Extent
                    0.0                     0.0                    -7.4

Area:
           Arctic Basin       East Siberian Sea              Laptev Sea
                  -22.7                     0.7                    -5.5
               Kara Sea             Barents Sea           Greenland Sea
                   -2.9                     0.1                    14.4
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -3.7                     0.0                    -0.3
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                    5.0                     1.3                    -1.2
             Bering Sea          Sea of Okhotsk              Total Area
                    0.0                     0.0                   -14.9

Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on September 02, 2013, 03:49:18 PM
Region of the day are the Svernya Zemly islands. It seems to sail the NE passage now, least ice will be found going around the islands. The continental coast seems to be blocked right now.

(attached image, log in to see)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on September 03, 2013, 04:58:57 PM
Update 20130902.

Extent: -48k7 (+1341k vs 2012)
Area: -7k1 (+1445k vs 2012)

Decreases in extent of CAB, CAA and ESS. CAB area on the contrary increased.

UPDATE: there is a triangular part missing (filled in by my program with values from yesterday). There maybe an update later tonight. See:
https://sites.google.com/site/apamsr2/home/pngcby32/Arc_20130902_res3.125_pyres.nc.png (https://sites.google.com/site/apamsr2/home/pngcby32/Arc_20130902_res3.125_pyres.nc.png)

 
You will find the updated graphs in the top post (https://forum.arctic-sea-ice.net/index.php/topic,382.0.html)

The details (in 1000 km2):


Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                  -18.1                    -8.3                    -3.0
               Kara Sea             Barents Sea           Greenland Sea
                   -3.1                    -0.6                    -6.6
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                    6.2                     0.0                     0.2
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                  -14.3                     1.1                    -2.1
             Bering Sea          Sea of Okhotsk            Total Extent
                    0.0                     0.0                   -48.7

Area:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   20.1                    -0.2                     1.0
               Kara Sea             Barents Sea           Greenland Sea
                   -1.3                    -0.4                   -23.0
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                    4.9                     0.0                     0.5
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                  -11.7                     2.7                     0.4
             Bering Sea          Sea of Okhotsk              Total Area
                    0.0                     0.0                    -7.1
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on September 03, 2013, 05:11:32 PM
Looking at the area of the Polar Polynya that is, somewhat surprisingly, growing. Is the Barents finally going to bite?

(log in to see atached image)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on September 03, 2013, 05:31:30 PM
And the color coded concentration map.

(log in etc)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on September 04, 2013, 08:00:06 AM
Update 20130903.

Extent: -66k3 (+1382k vs 2012)
Area: -62k1 (+1450k vs 2012)

Todays numbers don't show much signs of refreeze yet. The decline continues in the CAB and the Siberian seas. The CAA is a bit of a "swing region", but the strong declines in both extent and area are remarkable.
 
You will find the updated graphs in the top post (https://forum.arctic-sea-ice.net/index.php/topic,382.0.html)

The details (in 1000 km2):


Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                  -10.6                   -19.5                    -8.5
               Kara Sea             Barents Sea           Greenland Sea
                   -4.2                     0.0                     0.2
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                    6.4                     0.0                    -1.4
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                  -26.9                     1.9                    -3.9
             Bering Sea          Sea of Okhotsk            Total Extent
                    0.0                     0.0                   -66.3

Area:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   -5.0                   -20.5                   -10.5
               Kara Sea             Barents Sea           Greenland Sea
                   -6.5                     0.0                     3.5
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                    1.7                     0.0                    -0.9
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                  -25.5                     2.9                    -1.4
             Bering Sea          Sea of Okhotsk              Total Area
                    0.0                     0.0                   -62.1

Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on September 04, 2013, 08:14:12 AM
Region of the day is East Siberian Sea section. Ice is decreasing strongly, but only the fringe regions. The interior is quite especially compared with the Barents Bite.

(attached image can be seen when logged in)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on September 04, 2013, 08:24:58 AM
Here is the color coded map of the region.

(log in etc)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: jdallen on September 04, 2013, 08:47:44 AM
Region of the day is East Siberian Sea section. Ice is decreasing strongly, but only the fringe regions. The interior is quite especially compared with the Barents Bite.

Jim Hunt posted an interesting image of the Barent's side over on the blog. It is looking like the "slush" we were seeing may be melting out partially as we both anticipated. leaving isolated larger rounded floes behind.

The appearance yesterday north and slightly east of Svalbard is very striking:

http://lance-modis.eosdis.nasa.gov/imagery/subsets/?subset=Arctic_r03c04.2013246.terra.250m&vectors=coast (http://lance-modis.eosdis.nasa.gov/imagery/subsets/?subset=Arctic_r03c04.2013246.terra.250m&vectors=coast)

If you look at the area that is connecting with the huge polyna, you can see wispy banks of small floes on the southern edge, a feature which is reasonably consistent down towards the main pack.  If you examine the main pack proper, even there, you will see that there are areas which opened up, and which even now resemble what the 'bite' area looked like a couple of weeks ago.

Interesting melt season indeed.  It may be cold enough, but visually looking at it, it doesn't seem to be inclined to refreeze *yet*.  Can't seem to make up its mind, m'thinks.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on September 05, 2013, 07:32:03 AM
Update 20130904.

Extent: -25k8 (+1431k vs 2012)
Area: +16k4 (+1534k vs 2012)

The melt is slower than ever with most of it on the Siberian side. Yet none of the regions is showing an extent increase.

 
You will find the updated graphs in the top post (https://forum.arctic-sea-ice.net/index.php/topic,382.0.html)

The details (in 1000 km2):


Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                    1.3                    -7.1                    -2.0
               Kara Sea             Barents Sea           Greenland Sea
                   -7.3                     0.0                    -1.0
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -6.4                     0.0                    -1.1
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   -0.3                    -2.6                     0.6
             Bering Sea          Sea of Okhotsk            Total Extent
                    0.1                     0.0                   -25.8

Area:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   13.6                    -9.7                    -1.3
               Kara Sea             Barents Sea           Greenland Sea
                   -7.2                     0.0                     6.9
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -3.2                     0.0                    -0.6
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                    8.0                     8.4                     1.3
             Bering Sea          Sea of Okhotsk              Total Area
                    0.1                     0.0                    16.4

Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on September 05, 2013, 07:59:30 AM
The Polar Polynya has shrunk, yet the ice in the "Barentsz Bite" seem still to be falling apart.

(images attached, log in to see)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on September 06, 2013, 07:10:06 AM
Update 20130905.

Extent: -16k4 (+1422k vs 2012)
Area: -25k8 (+1514k vs 2012)

If not for the Greenland sea, the numbers would have hardly moved.
 
You will find the updated graphs in the top post (https://forum.arctic-sea-ice.net/index.php/topic,382.0.html)

The details (in 1000 km2):


Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                    0.7                    -5.8                    -0.8
               Kara Sea             Barents Sea           Greenland Sea
                    0.7                     0.0                   -15.9
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -1.6                     0.0                    -0.3
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                    4.0                     0.7                     2.0
             Bering Sea          Sea of Okhotsk            Total Extent
                    0.0                     0.0                   -16.4

Area:
           Arctic Basin       East Siberian Sea              Laptev Sea
                    7.1                    -4.0                    -0.6
               Kara Sea             Barents Sea           Greenland Sea
                   -0.6                     0.0                   -19.1
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -0.3                     0.0                     0.0
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   -2.0                    -7.5                     1.3
             Bering Sea          Sea of Okhotsk              Total Area
                    0.0                     0.0                   -25.8

Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on September 06, 2013, 07:19:59 AM
Highlight of the day is the Greenland sea (with sea ice). Today there are more reds than blues, I think it has to do with better atmospheric conditions (less clouds and vapor) making the ice edges sharper.

(image attached, log in to see)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on September 06, 2013, 07:26:48 AM
And the color coded concentration map.

(log in etc)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Alistair on September 06, 2013, 08:33:56 AM
Update 20130905.
If not for the Greenland sea, the numbers would have hardly moved.
 

In the past week the Greenland Sea has had a late season influx of ice from the CAB which I assume has then put it in contact with the last of the warmth to melt it.

Prior to this past week it seems that hardly any ice has flowed into the Fram for almost a month?
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on September 06, 2013, 09:12:42 AM
May be the animation helps.
I expect the Fram transport and Greenland sea extent to increase anytime soon. But visually I cannot be sure that anything has changed yet.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: LarsBoelen on September 06, 2013, 03:31:05 PM
Did everyone see the dinosaur fall of the cliff  :)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on September 06, 2013, 03:58:07 PM
Did everyone see the dinosaur fall of the cliff  :)

Looks like a Chinese style dragon to me.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: seattlerocks on September 06, 2013, 07:23:37 PM
Day 26?
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on September 07, 2013, 06:55:00 AM
                   -7.4                    -1.4                  1454.4
Update 20130906.

Extent: -26k2 (+1396k vs 2012)
Area: -17k0 (+1454k vs 2012)

Greenland Sea continues the decline that I noticed yesterday. The CAB extent went down and that of CAA increased.
 
You will find the updated graphs in the top post (https://forum.arctic-sea-ice.net/index.php/topic,382.0.html)

The details (in 1000 km2):


Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                  -14.6                    -5.1                    -2.1
               Kara Sea             Barents Sea           Greenland Sea
                    5.0                    -0.1                   -20.3
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -1.0                     0.0                     0.0
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   10.9                     0.1                     1.1
             Bering Sea          Sea of Okhotsk            Total Extent
                   -0.2                     0.0                   -26.2

Area:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   -2.2                    -3.7                    -1.7
               Kara Sea             Barents Sea           Greenland Sea
                    6.2                    -0.1                   -17.4
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -1.0                     0.0                     0.0
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   -0.6                     3.0                     0.6
             Bering Sea          Sea of Okhotsk              Total Area
                   -0.1                     0.0                   -17.0

Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on September 07, 2013, 07:07:30 AM
Area of the Barentsz / Kara "Bite". Strong winds from the south melt/compact and drive the ice. I would expect the polynya to be compacted away.

(image attached log in to see)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on September 07, 2013, 07:12:00 AM
And a color coded concentration map.

(attached, log in)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on September 08, 2013, 08:11:54 AM
Update 20130907.

Extent: -24k9 (+1437k vs 2012)
Area: -25k3 (+1404k vs 2012)

CAB decreased considerable, both in extent and area.
 
You will find the updated graphs in the top post (https://forum.arctic-sea-ice.net/index.php/topic,382.0.html)

The details (in 1000 km2):


Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                  -24.8                    -4.6                    -4.2
               Kara Sea             Barents Sea           Greenland Sea
                   -1.9                    -0.1                    11.4
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -1.2                     0.0                     0.0
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                    5.1                    -4.4                    -0.1
             Bering Sea          Sea of Okhotsk            Total Extent
                    0.0                     0.0                   -24.9

Area:
           Arctic Basin       East Siberian Sea              Laptev Sea
                  -38.6                    -5.1                    -2.9
               Kara Sea             Barents Sea           Greenland Sea
                    0.4                    -0.1                     9.8
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -1.2                     0.0                     0.0
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   11.8                    -1.4                     1.9
             Bering Sea          Sea of Okhotsk              Total Area
                    0.0                     0.0                   -25.3

Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on September 08, 2013, 08:39:33 AM
Just because, here is the delta over the first September week with the most intense melting. The Polar Polynya has grown, more smaller polynya's are born and the ice edge retreated considerably.

Today's color coded concentration map is included, both images can be seen if you are logged in.
Title: Polynya is moving toward the NP
Post by: paulklem on September 09, 2013, 05:49:23 AM
The polynya now is less than 200 km from the NP, and likely only 100-150km from combining with the area of broken ice pack around the NP. Weather is turning colder, but the prevailing winds will continue to push water from east into the pack and toward the pole. The current forecast shows a moderate LP cell will briefly push ice toward the Fram, but then as a HP cell sits over the areas in the CAB toward the East Siberian, the wind will again push into the pack.

Over the next weeK: Will the polynya compact away? Will the area around the NP refreeze before the two weak areas in the pack combine? Or will the edge of the pack recede enough to combine with the polynya, and keep shifting toward the NP? Conservatively we should expect not a lot of change from the current status, until refreezing really takes over.

But the pack is especially mobile, and shifting a lot right now (at the end of the melt season). The movement over the last couple of weeks has been striking. Even out along 90W and 85N, there are some big cracks in the pack continuing to open up and widening (as can be seen in the satellite images).

The melt this year has certainly been interesting, and the season is going to end that way.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on September 09, 2013, 07:09:13 AM
Update 20130908.

Extent: -13k7 (+1420k vs 2012)
Area: -11k1 (+1430k vs 2012)

The CAB continues to decline. The highly variable Greenland Sea went up and the equally variable CAA went down.
 
You will find the updated graphs in the top post (https://forum.arctic-sea-ice.net/index.php/topic,382.0.html)

The details (in 1000 km2):


Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                  -15.3                    -3.6                    -2.3
               Kara Sea             Barents Sea           Greenland Sea
                   -0.3                     0.5                    20.3
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                    4.9                     0.0                     1.5
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                  -13.3                    -3.3                    -2.7
             Bering Sea          Sea of Okhotsk            Total Extent
                    0.0                     0.0                   -13.7

Area:
           Arctic Basin       East Siberian Sea              Laptev Sea
                  -20.0                    -4.0                    -1.2
               Kara Sea             Barents Sea           Greenland Sea
                   -0.7                     0.3                    23.0
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                    4.5                     0.0                     1.0
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                  -12.3                     0.4                    -2.2
             Bering Sea          Sea of Okhotsk              Total Area
                    0.0                     0.0                   -11.1

Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on September 09, 2013, 07:22:39 AM
As Paul noticed, the Polar Polynya is moving closer to the NP. Today it moved especially fast as seen on the 1 day difference map.

(images attached, visible when logged in)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on September 09, 2013, 07:50:07 AM
A look at NE Greenland. I still don't see much increase of the Fram Strait transport. The ice fasted on Belgica Bank looks shattered.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: LarsBoelen on September 09, 2013, 12:49:46 PM
Wipneus,

I've been tracking that region since on august 14th the fast ice broke loose and crumbled. I tracked a 30x60 km chunk that drifted east at about 5 km/day. Would be interesting to compare this years "throughput" with other years: is this one of the resons so much thick ice is left his year? And if so, what does the lack of Fram Straight transport mean for North Atlantic climate?
http://youtu.be/j-Y3xKY-Nh8 (http://youtu.be/j-Y3xKY-Nh8)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on September 09, 2013, 03:08:19 PM
Would be interesting to compare this years "throughput" with other years:

For Uni Hamburgs AMSR2 3.125km analysis, we have to wait when/if they will make data for 2012 available. In the mean time there are maps from Bremen University.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fwww.iup.uni-bremen.de%3A8084%2Famsr2data%2Fasi_daygrid_swath%2Fn3125%2F2012%2Fsep%2FGreenlandSea%2Fasi-AMSR2-n3125-20120908_visual.png&hash=97a42d232bf40e09bd5503f1f9759731)

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fwww.iup.uni-bremen.de%3A8084%2Famsr2data%2Fasi_daygrid_swath%2Fn3125%2F2013%2Fsep%2FGreenlandSea%2Fasi-AMSR2-n3125-20130908_visual.png&hash=922d6e7f2795824c628f90f268524965)

There is no doubt that the reduced Fram export  has contributed to the higher amount of total Arctic sea ice in 2013 and the low amount in the Greenland Sea.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: LarsBoelen on September 09, 2013, 03:40:41 PM
Thanks Wipneus,

Yes, that's what i meant.

What is immediately evident from these two pictures is the much worse condition of the ice above 80N, above 82N there are even holes in the ice (polynea they are called i believe). If winds turns favorable for export to restart that would mean very portable ice, and lots of surface area for the wind to grasp on to. That in turn would lead to a rapid "regrowth" of the Greenland sea, but much slower regrowth in the arctic basin north of Greenland. It seems that this interesting summer is going to be followed by an even more interesting autumn.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: LarsBoelen on September 09, 2013, 03:48:39 PM
And what is this area of luke warm water across the Greenland Sea? No wonder the ice melts so quickly? The spot SW of Spitsbergen is 10 degrees warmer than normal? Did an underwater volcano erupt there?

LOL, look at this
(wattsupwiththat) /2013/08/02/hot-times-near-svalbard-volcanic-range-discovered/[/url]
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Vergent on September 09, 2013, 05:50:27 PM
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fstatic.guim.co.uk%2Fsys-images%2FGuardian%2FPix%2Fpictures%2F2013%2F9%2F9%2F1378692793547%2FArcticEscalator450.gif&hash=b54f07043a797f483fca74033e1f8684)

http://www.theguardian.com/environment/climate-consensus-97-per-cent/2013/sep/09/climate-change-arctic-sea-ice-delusions (http://www.theguardian.com/environment/climate-consensus-97-per-cent/2013/sep/09/climate-change-arctic-sea-ice-delusions)

Vergent
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Anne on September 09, 2013, 06:14:45 PM
That article was good, Vergent. There has been a lot of this "ice cover grew by 60%" delusion, not just in the Torygraph and the Daily Fail. There's a complete failure to understand what extent is, let alone the regression to the mean. Sorry, I'm feeling a bit ranty right now, having seen more idiot comments about the growth Antarctica sea ice. These people just want to believe what makes them feel comfortable and superior, and I won't derail this thread any longer. Grrr.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: johnm33 on September 09, 2013, 10:08:22 PM
LarsB I've been looking at that area trying to figure out whats occurring for 2 years. Look at the zoomable bathymetric  over at arcticio and there seems to be a waterfall dropping off the shelf thereabouts which I'm assuming [until someone comes up with a better idea] creates  vortices which interfere with one another and thus expose the warmer layers of AW below.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: helorime on September 09, 2013, 10:11:37 PM
Looking at today's polar MODIS:  Cloud cover is down a bit at the pole compared to the last fer days and it really looks like the Polar Polynya has not only moved substantially closer to the pole as Wipneus has noted and shown, but that it has really opened up to the Barentsz byte.

http://rapidfire.sci.gsfc.nasa.gov/imagery/subsets/?mosaic=Arctic.2013252.terra.1km (http://rapidfire.sci.gsfc.nasa.gov/imagery/subsets/?mosaic=Arctic.2013252.terra.1km)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: jdallen on September 10, 2013, 05:12:35 AM
And what is this area of luke warm water across the Greenland Sea? No wonder the ice melts so quickly? The spot SW of Spitsbergen is 10 degrees warmer than normal? Did an underwater volcano erupt there?

LOL, look at this...

Not. Even. Close.

The amount of heat required to raise the temps off Greenland dwarfs the output of that range. I think the long exposure of sea surface there may have some interesting long term effects.  Lost fast ice will be replaced by ~ 2m thick FYI, which may lead to faster break up next spring. This presumes it will freeze over; weather may interfere, transporting weak ice out before it has a chance to get established. It will be interesting to watch.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on September 10, 2013, 08:05:27 AM
Update 20130909.

Extent: -58k6 (+1305k vs 2012)
Area: -83k6 (+1361k vs 2012)

Large declines for the time of year. The CAB, CAA and Greenland Sea substantially. All other regions contribute.
 
You will find the updated graphs in the top post (https://forum.arctic-sea-ice.net/index.php/topic,382.0.html)

The details (in 1000 km2):


Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                  -10.7                    -4.8                    -3.5
               Kara Sea             Barents Sea           Greenland Sea
                   -6.1                     0.0                    -9.5
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -1.1                     0.0                    -1.6
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                  -16.2                    -2.0                    -3.1
             Bering Sea          Sea of Okhotsk            Total Extent
                    0.0                     0.0                   -58.6

Area:
           Arctic Basin       East Siberian Sea              Laptev Sea
                  -40.7                    -3.0                    -1.8
               Kara Sea             Barents Sea           Greenland Sea
                   -6.7                     0.1                   -16.2
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -1.7                     0.0                    -1.0
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   -9.7                     0.6                    -3.4
             Bering Sea          Sea of Okhotsk              Total Area
                    0.0                     0.0                   -83.6

Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on September 10, 2013, 08:27:59 AM
The area of the Polar Polynya and Bartentsz is still the most interesting region. The movement of the polynya is still strongly polewards and the smaller ones are growing.
For orientation, the cross marks the North Pole. The width of the Polar Polynya is about 125km.

(images attached, to see them you should log in) 
Title: Re: Home brew AMSR2 extent & area calculation
Post by: jdallen on September 10, 2013, 05:09:36 PM
I wonder, if the clouds which previously slowed the melt, are now moderating in the other direction, and extending it?

This kind of drop may also illustrate the weaken nature of the ice.  We have area, we have extent, but lower volume and even less coherence in the pack.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on September 10, 2013, 06:10:40 PM
2012 did continue the decline till mid September (say the 16th). It is a bit of speculation whether  2013 will continue longer:

The most simplistic explanation is that since there is so much more extent and area, there is more room for melt also at lower latitudes.
That does not explain the continuing strong melt in the Atlantic section of the CAB, there is compared with 2012 much less ice present.
A third factor is the Greenland Sea, at the same time last year it was past the seasonal minimum. Now area and extent are far lower and only jump a bit up and down since beginning of August.

Here is a map with the extent differences 2012-2013 as seen by AMSR2, processed by Jaxa.
(https://sites.google.com/site/arctischepinguin/home/asib/tmpjaxa.png)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: jdallen on September 10, 2013, 06:52:54 PM
2012 did continue the decline till mid September (say the 16th). It is a bit of speculation whether  2013 will continue longer:

The most simplistic explanation is that since there is so much more extent and area, there is more room for melt also at lower latitudes.
That does not explain the continuing strong melt in the Atlantic section of the CAB, there is compared with 2012 much less ice present.
A third factor is the Greenland Sea, at the same time last year it was past the seasonal minimum. Now area and extent are far lower and only jump a bit up and down since beginning of August.

Here is a map with the extent differences 2012-2013 as seen by AMSR2, processed by Jaxa. ...

I wish we had better data on water temps and currents.  A fundamental problem with buoys is, they are sitting on ice, and stop giving us data when it's gone :-\

Inflow of Atlantic water is the only source I can think of for the heat required to produce 80K (!) drops so late. There is a lot of heat in the Barents, which was open all season. I am open to other suggestions.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Bob Wallace on September 10, 2013, 08:35:32 PM
Quote
The most simplistic explanation is that since there is so much more extent and area, there is more room for melt also at lower latitudes.

Yes, look at your regional graphs and when refreeze started last year in those lower latitude regions.  They reached zero earlier and then sat flat for weeks.  Unless the water is considerably colder there this year or winter comes early one would assume melting to continue. 

The ESS doesn't start showing new ice until the second week of October.  The CAA the first week of October.  The Beaufort mid-October.

My question of the moment is whether we'll see early extent increases in the CAB or will it be fill-in freezing early and growth later.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on September 11, 2013, 07:04:24 AM
Update 20130910.

Extent: +7k3 (+1303k vs 2012)
Area: +24k6 (+1273k vs 2012)

Despite a small net uptick the distance with 2012 is less than it has been for a week.
Today the small decline of the CAB was offset by sea ice increases in the Greenland Sea and CAA.   

You will find the updated graphs in the top post (https://forum.arctic-sea-ice.net/index.php/topic,382.0.html)

The details (in 1000 km2):


Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                  -13.4                    -0.6                    -1.2
               Kara Sea             Barents Sea           Greenland Sea
                   -2.1                    -0.3                    10.6
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                    4.4                     0.0                     0.0
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                    9.0                     2.3                    -1.4
             Bering Sea          Sea of Okhotsk            Total Extent
                    0.0                     0.0                     7.3

Area:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   -2.8                    -1.1                    -0.6
               Kara Sea             Barents Sea           Greenland Sea
                   -1.5                    -0.2                    15.5
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                    4.0                     0.0                     0.0
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                    8.3                     3.6                    -0.4
             Bering Sea          Sea of Okhotsk              Total Area
                    0.0                     0.0                    24.6

Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on September 11, 2013, 07:29:39 AM
Images of Barentsz Bite area. The Polar Polynya is shrinking, while the smaller ones are growing. The ice separating them from open ocean is now in places no more than 25km wide, the "pixel" size in NSIDC and CT images.

(log in to see the images)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on September 12, 2013, 06:55:34 AM
Update 20130911.

Extent: +6k7 (+1358k vs 2012)
Area: +36k9 (+1354k vs 2012)

So we are near the start of the freezing season. A very big area increase in the CAB is an indication. An increase of extent in the Greenland sea is another factor. In other regions melt continues slowly.

 
You will find the updated graphs in the top post (https://forum.arctic-sea-ice.net/index.php/topic,382.0.html)

The details (in 1000 km2):


Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                    9.6                    -6.6                    -0.2
               Kara Sea             Barents Sea           Greenland Sea
                   -5.8                     0.0                    16.8
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                    3.4                     0.0                     0.4
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   -4.3                    -5.9                    -0.7
             Bering Sea          Sea of Okhotsk            Total Extent
                    0.0                     0.0                     6.7

Area:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   39.8                    -6.3                     0.2
               Kara Sea             Barents Sea           Greenland Sea
                   -3.2                     0.0                    14.7
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                    2.4                     0.0                     0.3
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   -5.8                    -4.6                    -0.6
             Bering Sea          Sea of Okhotsk              Total Area
                    0.0                     0.0                    36.9

Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on September 12, 2013, 07:27:16 AM
Because we are at, or very near at, minimum ice, here is an overview of the remaining pack.

In the Barents Bite section, ice increasing and the polynya closing. Apart from that, melting is occurring along the ice edge from the Beaufort to the Laptev Sea. The Parry Channle in the Canadian Archipelago is clearing. Finally there is no indication that the Fram Starit export is taking up.

(log in to see attached image)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on September 12, 2013, 08:17:16 AM
I have been looking at this patch of low concentration ice, situated halfway Svalbard and the NP.
It developed in the beginning of August and has not moved or changed appearance much since.

(image grey levels slightly enhanced)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Neven on September 12, 2013, 11:28:18 AM
Yet another hole that hasn't had the time to fully develop.  :)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: jdallen on September 12, 2013, 06:47:53 PM
Yet another hole that hasn't had the time to fully develop.  :)
Remove the May/June pause (~3 weeks of slow melt) and it all (the weak, dispersed areas) disappears. Slow spring did save the ice, along with increased cloud cover overall, seems.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on September 13, 2013, 06:24:33 AM
Update 20130912.

Extent: -3k5 (+1416k vs 2012)
Area: +39k2 (+1453k vs 2012)

The big increase in CAB area shows the freezing season is near. A small decline of the CAB extent is still possible. All other changes are small.

 
You will find the updated graphs in the top post (https://forum.arctic-sea-ice.net/index.php/topic,382.0.html)

The details (in 1000 km2):


Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   -5.3                    -1.1                     0.1
               Kara Sea             Barents Sea           Greenland Sea
                   -1.0                    -0.1                     4.7
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -5.9                     0.0                     1.5
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   10.1                    -5.7                    -1.0
             Bering Sea          Sea of Okhotsk            Total Extent
                    0.2                     0.0                    -3.5

Area:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   35.8                     2.1                    -0.1
               Kara Sea             Barents Sea           Greenland Sea
                   -0.5                    -0.1                     2.6
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -3.6                     0.0                     1.2
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                    7.4                    -4.7                    -1.0
             Bering Sea          Sea of Okhotsk              Total Area
                    0.1                     0.0                    39.2

Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on September 13, 2013, 06:42:57 AM
The Polar Polynya has closed, probably frozen over. The ice edge north of Svalbard-Frans Josef lLand is still retreating.

(images attached)


Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on September 14, 2013, 08:04:37 AM
Update 20130913.

Extent: +27k5 (+1395k vs 2012)
Area: +24k8 (+1435k vs 2012)

Large uptick for the CAA today, which may be reversed tomorrow. The rise in the Greenland Sea could be a trend, it has been increasing for a week now. The CAB still shows declines.
 
You will find the updated graphs in the top post (https://forum.arctic-sea-ice.net/index.php/topic,382.0.html)

The details (in 1000 km2):


Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   -5.9                     2.8                    -0.7
               Kara Sea             Barents Sea           Greenland Sea
                    4.6                     0.1                     7.6
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                    1.6                     0.0                    -1.1
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   21.0                    -1.6                    -0.7
             Bering Sea          Sea of Okhotsk            Total Extent
                   -0.1                     0.0                    27.5

Area:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   -5.8                     4.7                    -0.5
               Kara Sea             Barents Sea           Greenland Sea
                    3.8                     0.1                    11.4
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                    1.4                     0.0                    -0.9
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   14.7                    -3.3                    -0.8
             Bering Sea          Sea of Okhotsk              Total Area
                    0.0                     0.0                    24.8

Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on September 14, 2013, 08:21:36 AM
A small cyclone causes the ice edge to retreat on the Laptev side and to advance to the Kara seas. The NE passage is wide open, around Severnaya Zemlya islands.

(image is attached, log in to see)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on September 14, 2013, 09:01:48 AM
Here is a Greenland Sea animation of the last week, actually I don't see much evidence of an increase of the Fram transport. Some larger digital artifacts (squares bigger than the 3.125km pixel size) shows that the Arstist Sea Ice (ASI) algorithm has some trouble on the ice edge here.


Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on September 14, 2013, 09:07:34 AM
For comparison, a week in June.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: jdallen on September 14, 2013, 10:30:47 AM
Here is a Greenland Sea animation of the last week, actually I don't see much evidence of an increase of the Fram transport. Some larger digital artifacts (squares bigger than the 3.125km pixel size) shows that the Arstist Sea Ice (ASI) algorithm has some trouble on the ice edge here.

I agree - certainly doesn't look like much movement at all out of the Fram.

Intuition/what I'm seeing suggests a refreeze; however, from what I've seen elsewhere regarding weather, neither the air or sea surface temps are low enough to support that.  I wonder what's going on?
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on September 14, 2013, 11:25:33 AM
Here is a Greenland Sea animation of the last week, actually I don't see much evidence of an increase of the Fram transport. Some larger digital artifacts (squares bigger than the 3.125km pixel size) shows that the Arstist Sea Ice (ASI) algorithm has some trouble on the ice edge here.

I agree - certainly doesn't look like much movement at all out of the Fram.

Intuition/what I'm seeing suggests a refreeze; however, from what I've seen elsewhere regarding weather, neither the air or sea surface temps are low enough to support that.  I wonder what's going on?

There is a 980mbar cyclone before the east coast, I think this causes the following to be applicable:

Quote
3.1. Weather Filters
   One disadvantage of the 89 GHz channels is the pro-
nounced influence of atmospheric cloud liquid water and
water vapor on the brightness temperatures. Especially cy-
clones over open water can reduce the polarization differ-
ence to values similarly small as those of sea ice. Therefore
effective filters are necessary to remove spurious ice concen-
tration in open water areas. The weather filtering process
consists of three steps. All of them use the lower frequency
channels with lower spatial resolution. This does not lead to
a lower resolution of the marginal ice zone [Kaleschke et al.,
2001] but it may cause pixels along the ice edge to show too
high ice concentrations due to missing weather filters. If this
is the case the resolution of the ice edge is determined by
the resolution of the weather filter.


Spreen, G., L. Kaleschke, G. Heygster (2008), "Sea Ice Remote Sensing Using AMSR-E 89
GHz Channels", J. Geophys. Res., 113, C02S03, doi:10.1029/2005JC003384.

So, water vapor and liquid water in clouds (associated with weather fronts) cannot be compensated in the hi resolution over the very fragmented ice cover (it is all edge actually)  of the Greenland Sea.
Wait for the clouds to clear, and the ice concentration should drop.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Richard Rathbone on September 14, 2013, 01:45:01 PM
I'd have thought that clear skies now would mean lower temperatures and more ice forming.

I assume you are talking about a measurement artefact going away, but it might be difficult to spot that against the actual refreeze I'd expect from clearer skies.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on September 14, 2013, 02:07:46 PM
Richard, if you look ate the regional graphs refreeze is not to be expected before October in all regions except the CAB and perhaps the CAA.
The Greenland Sea is a region where melt will dominate most of the year. The Fram Strait transport is most important there.

(https://sites.google.com/site/arctischepinguin/home/amsr2/grf/amsr2-area-regional.png)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Richard Rathbone on September 14, 2013, 08:55:10 PM
I don't think 2012 is a good guide to the timing of regional refreezes this year. Refreeze will start earlier than 2012 in regions that melted out in 2012 and haven't melted out this year. Fram Transport gives the Greenland Sea its own pattern, but seas like the Beaufort are going to start refreezing much earlier, because the ice edge is still in them and hasn't got to freeze its way back out of the CAB first. Or to put it another way, the ocean at the CAB/Beaufort boundary has had ice sitting on top of it stopping whatever sun there has been from heating the water up, and the heat that didn't get in, doesn't have to get out before it starts refreezing.

There's still scope for the wind to push the edge around for a while, but the minimum is about now, and that means new ice is starting to appear around the pack edge in whatever seas the edge is in now.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on September 15, 2013, 08:21:41 AM
Update 20130914.

Extent: +1k2 (+1482k vs 2012)
Area: -5k2 (+1455k vs 2012)

Minimal net changes, but the regional numbers of the CAB, CAA and Greenland Sea say otherwise. The CAA extent and area increase, while that of the CAB and  the Greenland Sea declines.
 
You will find the updated graphs in the top post (https://forum.arctic-sea-ice.net/index.php/topic,382.0.html)

The details (in 1000 km2):


Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                  -19.1                     2.0                     0.0
               Kara Sea             Barents Sea           Greenland Sea
                    3.5                    -0.1                    -8.7
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                    1.6                     0.0                    -0.6
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   22.9                    -0.9                     0.8
             Bering Sea          Sea of Okhotsk            Total Extent
                   -0.1                     0.0                     1.2

Area:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   -8.1                    -0.7                    -0.1
               Kara Sea             Barents Sea           Greenland Sea
                    2.8                    -0.1                   -19.1
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                    0.6                     0.0                    -0.5
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   16.1                     3.3                     0.6
             Bering Sea          Sea of Okhotsk              Total Area
                   -0.1                     0.0                    -5.2

Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on September 15, 2013, 09:14:04 AM
The far side (seen from where I live, the Netherlands) has not been the subject of the region of the day. There has been a slow net decline, a mixture of "reds" and "blues". Looking at today's delta map, a movement for Canada -> Siberia can be seen. The crack above Prince Patrick Island underlines that.

(log in to see the image)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on September 15, 2013, 09:26:14 AM
And an animation of the cracks above the Canadian Archiplago. As I see it, a great mass of the CAB ice is moving suddenly in NW direction. For weeks the ice movement was south, into the channels between the islands.

(click on the image if there is no animation)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on September 15, 2013, 09:35:36 AM
I don't think 2012 is a good guide to the timing of regional refreezes this year. Refreeze will start earlier than 2012 in regions that melted out in 2012 and haven't melted out this year.

Richard, if I expected a duplication of 2012, I would have said "mid October". Anyway, the Greenland Sea dropped today from 101k to 81k with the cyclone loosing intensity but the area still under thick clouds.

Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on September 16, 2013, 08:14:02 AM
Update 20130915.

Extent: -14k1 (+1421k vs 2012)
Area: +5k4 (+1428k vs 2012)

Melt continues as the CAB figures show. The Greenland Sea extent and area decline as expected due to better weather conditions. Opposite are CAA and Baffin, some channels are filling up with ice drift from the CAB, including the Nares Strait (which is part of the Baffin region). 
 
You will find the updated graphs in the top post (https://forum.arctic-sea-ice.net/index.php/topic,382.0.html)

The details (in 1000 km2):


Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                  -16.7                    -2.2                    -0.3
               Kara Sea             Barents Sea           Greenland Sea
                   -6.7                     0.2                   -14.1
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                    8.5                     0.0                    -0.1
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   12.8                     2.9                     1.7
             Bering Sea          Sea of Okhotsk            Total Extent
                    0.1                     0.0                   -14.1

Area:
           Arctic Basin       East Siberian Sea              Laptev Sea
                    0.5                    -2.5                    -0.3
               Kara Sea             Barents Sea           Greenland Sea
                   -7.3                     0.2                    -5.5
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                    6.1                     0.0                    -0.1
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   10.0                     2.4                     1.8
             Bering Sea          Sea of Okhotsk              Total Area
                    0.1                     0.0                     5.4

Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on September 16, 2013, 08:37:58 AM
Yesterday I showed the "far" side of the pack, now the opportunity for the "near" or Atlantic side.

Melt along the edge all over.

(image attached log in to see)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Richard Rathbone on September 16, 2013, 02:52:45 PM
I don't think 2012 is a good guide to the timing of regional refreezes this year. Refreeze will start earlier than 2012 in regions that melted out in 2012 and haven't melted out this year.

Richard, if I expected a duplication of 2012, I would have said "mid October". Anyway, the Greenland Sea dropped today from 101k to 81k with the cyclone loosing intensity but the area still under thick clouds.

Clearly I am not understanding what you think your graphs show.

All I am trying to say is that there are competing effects going on and that its dangerous to draw any inference from a daily change correlating with one effect without also checking that it doesn't correlate against other effects that are in play. In particular I am claiming that refreeze is in play now and disputing that 2012 is a good analogue for when refreeze comes into play.

As for whether refreeze is in play in the Greenland Sea now, Greenland itself is refreezing exceptionally fast this September (its above the 2 standard deviation region on the surface mass balance plot http://beta.dmi.dk/en/groenland/maalinger/greenland-ice-sheet-surface-mass-budget/ (http://beta.dmi.dk/en/groenland/maalinger/greenland-ice-sheet-surface-mass-budget/)). W and S coasts are still showing mass balance reduction but NE is accumulating. Ice going south to melt is the dominant process, but I don't think you can rule out freezing in the part closest to NE Greenland.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: jdallen on September 16, 2013, 07:21:24 PM
@Richard R - refreeze north of the Fram - maybe.  South of the Fram neither SSTs nor 2 meter temps are low enough yet. They are barely low enough across the top of the island.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on September 17, 2013, 07:09:06 AM
Update 20130916.

Extent: -9k8 (+1428k vs 2012)
Area: -23k4 (+1432k vs 2012)

A net decline day again. In the Beaufort the ice increased and more ice is entering the Baffin region, but the CAB continued its decline and the CAA and Greenland Sea recovered from the previous increases.

 
You will find the updated graphs in the top post (https://forum.arctic-sea-ice.net/index.php/topic,382.0.html)

The details (in 1000 km2):


Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                  -15.7                    -5.8                     0.2
               Kara Sea             Barents Sea           Greenland Sea
                    0.7                     0.1                    -5.4
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                    6.4                     0.0                     0.3
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   -7.5                    14.5                     2.6
             Bering Sea          Sea of Okhotsk            Total Extent
                   -0.1                     0.0                    -9.8

Area:
           Arctic Basin       East Siberian Sea              Laptev Sea
                  -12.3                    -7.8                     0.1
               Kara Sea             Barents Sea           Greenland Sea
                    1.2                     0.1                   -11.2
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                    3.0                     0.0                     0.2
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   -8.5                     9.7                     2.2
             Bering Sea          Sea of Okhotsk              Total Area
                   -0.1                     0.0                   -23.4

Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on September 17, 2013, 07:31:49 AM
So how about the minimum? Since in the daily report I normally note the changes that is not easy to follow. Here are the absolute numbers last ten days:

YYYYMMDD Total.Extent Total.Area
20130907     4.693800   4.344824
20130908     4.680139   4.333682
20130909     4.621491   4.250043
20130910     4.628799   4.274677
20130911     4.635514   4.311544
20130912     4.631994   4.350772
20130913     4.659530   4.375571
20130914     4.660765   4.370364
20130915     4.646696   4.375721
20130916     4.636934   4.352362


So the minimum was on Sep 9. Yet the extent is only about 15k above that, so extent could stiil be lower.

So has the refreeze started? I think you can argue it has not. Most of the increases have come from the disappearance of melt pools (affecting mostly CAB area) and the peripheral regions. These can be shown are affected by increasing bad weather and ice transport.

Further, refreeze should be shown first in the CAB (as it contains the NP). For these reasons I prefer (and I argued this in this thread before) to look at the CAB extent.
These are the numbers for the CAB:

YYYYMMDD Arctic.Basin.extent Arctic.Basin.area
 20130907            3.795692          3.593694
 20130908            3.780346          3.573741
 20130909            3.769694          3.533063
 20130910            3.756253          3.530225
 20130911            3.765868          3.570044
 20130912            3.760546          3.605888
 20130913            3.754614          3.600090
 20130914            3.735482          3.591955
 20130915            3.718788          3.592422
 20130916            3.703126          3.580083


Area was minimum at Sep 10 (50k below current) but extent is now at its lowest.

Remember that near real time regional extent was not available before (since nobody bothered to do the calcs).

In my definition, refreeze cannot be said to have started yet.
 
Title: Re: Home brew AMSR2 extent & area calculation
Post by: TerryM on September 17, 2013, 08:22:25 AM
Wipneus

"[size=78%]Most of the increases have come from the disappearance of melt pools"[/size][/i]
Wouldn't melt pond freezing be showing as area increase as opposed to extent? I'm in agreement that refreeze hasn't started yet, at least in any meaningful way, but I am confused about melt ponds at this time of year as well as their freezing leading to higher extent figures.
Terry
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on September 17, 2013, 09:09:56 AM
Terry, sorry I was so short. I had to catch a train. Which has terrible wifi btw.

It is an assumption that area decline in the CAB is mostly caused by freezing melt pools. If there are arguments otherwise, I'd like to hear them.

The compactness is nearly back to winter levels, all methods except the Crysosphere Today  derived CAPIE index. Since meltpools must (by physics) lower compactness, these should be minimal by now. See the compactness graphic if in doubt.   
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Peter Ellis on September 17, 2013, 06:33:29 PM
I think this is falling into a semantic trap - some people are taking "refreeze" as starting when the melt ponds freeze over, while others are taking it to be when the sea between adjacent ice floes starts to freeze over. Both definitions are defensible, and the refreeze has started by the former metric but likely not yet by the latter.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on September 18, 2013, 06:05:23 AM
Update 20130917.

Extent: +10k2 (+1418k vs 2012)
Area: +12k2 (+1432k vs 2012)

Add another melt day for the CAB, most other regions are quiet or have slight increases.
 
You will find the updated graphs in the top post (https://forum.arctic-sea-ice.net/index.php/topic,382.0.html)

The details (in 1000 km2):


Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                  -12.2                     2.6                     0.3
               Kara Sea             Barents Sea           Greenland Sea
                    1.6                    -0.2                     8.8
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -4.1                     0.0                    -0.6
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                    5.5                     7.2                     1.3
             Bering Sea          Sea of Okhotsk            Total Extent
                    0.0                     0.0                    10.2

Area:
           Arctic Basin       East Siberian Sea              Laptev Sea
                  -19.0                     0.6                     0.2
               Kara Sea             Barents Sea           Greenland Sea
                    2.2                    -0.2                    13.4
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -1.4                     0.0                    -0.3
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   11.1                     4.9                     0.7
             Bering Sea          Sea of Okhotsk              Total Area
                    0.0                     0.0                    12.2

Title: Re: Home brew AMSR2 extent & area calculation
Post by: Bob Wallace on September 18, 2013, 06:08:32 AM
CAB - melting or outsourcing?

CA and GS are up just a bit more than the CAB is down.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on September 18, 2013, 07:14:29 AM
I cannot see a region interesting enough to single out. Therefore a changed extent ice map for the 8 days after the total minimum extent (20130909).
Things to notice:
 CAB Polynya mostly gone   :(
 ice seriously increases in CAA and the Nares Strait (region Baffin);
 ice gets a little more south in the Greenland Sea (I don't think that is significant);
 There is a huge widening of the gap between Banks Island and the ice pack;
 Ice edge advancing in the Beaufort;
 The resisting ice field in the ESS is moving west;
 Ice retreating from the edges of the Laptev, Kara and Barentsz section;

The image is attached, log in to see.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on September 18, 2013, 07:32:49 AM
CAB - melting or outsourcing?


Yes Bob, that is the question, to which the easy answer is of course "both". I have been trying to collect some fact in the previous weeks. There is probably some freezing as well: just north of the Canadian Islands, some cracks developed last week.  The wide crack above Prince Patrick did not close, but is now filled with low concentration ice. Such cracks can close again and lower extent without any melting or "outsourcing".

Quote

CA and GS are up just a bit more than the CAB is down.

Yes but the changes are so small that there is not so much meaning there.
At the same time last year, CAB extent increased 63k according to my Jaxa calculations. According to the official Jaxa/IJIS V2 numbers, Sep 17 2012 scored its first positive century (+106k).

Just underlining 2013 is a remarkable year, at least it is not 2012.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Frivolousz21 on September 18, 2013, 09:44:16 AM
I doubt we could even walk on the "new" CAA ice.


Passive Microwave during the Summer when it's much warmer misses ice much thicker and more widespread than what is going on in the CAA.

Give me a break.  The models show much warmer air moving in soon.  Above freezing air with a strong Southerly flow.  We will probably see all of that new ice vanish.


(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi174.photobucket.com%2Falbums%2Fw109%2Ffrivolousz21%2Ffrivolousz21024%2F4c2b5676-5d50-4d2c-805e-7bd1d428ca8c_zps868c16ad.jpg%3Ft%3D1379479577&hash=5e6ed34039ef56cab6a55c95f0a02b9c)


(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2F%5Burl%3Dhttp%3A%2F%2Fi174.photobucket.com%2Falbums%2Fw109%2Ffrivolousz21%2Ffrivolousz21024%2FArcticseaiecjaxa_zpsfbfedab8.jpg%5Dhttp%3A%2F%2Fi174.photobucket.com%2Falbums%2Fw109%2Ffrivolousz21%2Ffrivolousz21024%2FArcticseaiecjaxa_zpsfbfedab8.jpg%5B%2Furl%5D&hash=dd6893636b03fa1b1acddb41835aa0bb)



Title: Re: Home brew AMSR2 extent & area calculation
Post by: jdallen on September 18, 2013, 09:42:31 PM
I doubt we could even walk on the "new" CAA ice.


Passive Microwave during the Summer when it's much warmer misses ice much thicker and more widespread than what is going on in the CAA.

Give me a break.  The models show much warmer air moving in soon.  Above freezing air with a strong Southerly flow.  We will probably see all of that new ice vanish.


I'm at least partly with Friv on this.  There looks to be a lot of energy still being dumped into low clouds which implies to me sea surfaces which are more rather than less open.  Add to that, that the temps still look marginal for ice formation, there may be other explanations for the uptic.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on September 19, 2013, 06:19:52 AM
Update 20130918.

Extent: +39k3 (+1494k vs 2012)
Area: +43k1 (+1516k vs 2012)

CAA and Greenland Sea have rather big increases, smaller for the Beaufort. Among this the CAB still manages a small decline, reaching another new CAB extent minimum.
 
You will find the updated graphs in the top post (https://forum.arctic-sea-ice.net/index.php/topic,382.0.html)

The details (in 1000 km2):


Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   -4.8                    -1.1                    -0.6
               Kara Sea             Barents Sea           Greenland Sea
                    2.2                     0.3                    12.6
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                    2.5                     0.0                     0.0
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   19.6                     6.4                     2.2
             Bering Sea          Sea of Okhotsk            Total Extent
                    0.0                     0.0                    39.3

Area:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   -3.9                    -0.4                    -0.4
               Kara Sea             Barents Sea           Greenland Sea
                    0.0                     0.2                    24.1
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                    2.4                     0.0                     0.0
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   13.8                     5.1                     2.3
             Bering Sea          Sea of Okhotsk              Total Area
                    0.0                     0.0                    43.1

Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on September 19, 2013, 06:35:34 AM
The Polar Polynya opened again, with some in what is known as the Barents Bite.

(log in to see attached images)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on September 20, 2013, 07:52:24 AM
Update 20130919.

Extent: +39k6 (+1474k vs 2012)
Area: +11k4 (+1483k vs 2012)

Ice is increasing in most regions, including the CAB which may be past its minimum now.
 
You will find the updated graphs in the top post (https://forum.arctic-sea-ice.net/index.php/topic,382.0.html)

The details (in 1000 km2):


Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                    8.8                    -2.9                     0.8
               Kara Sea             Barents Sea           Greenland Sea
                   -2.6                    -0.2                     7.2
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                    0.1                     0.0                    -0.1
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   22.6                     1.3                     4.3
             Bering Sea          Sea of Okhotsk            Total Extent
                    0.0                     0.0                    39.6

Area:
           Arctic Basin       East Siberian Sea              Laptev Sea
                    4.4                    -7.9                     0.4
               Kara Sea             Barents Sea           Greenland Sea
                   -3.7                    -0.1                    -1.3
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -1.4                     0.0                    -0.1
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   18.4                     0.0                     2.6
             Bering Sea          Sea of Okhotsk              Total Area
                    0.0                     0.0                    11.4

Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on September 20, 2013, 08:04:29 AM
With ice now increasing everywhere, the East Siberian Sea has the largest slice of ice that is disappearing. Looking at the changes image shows that the ice is actually moving (by winds) west.

(log in to see attached image)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on September 21, 2013, 07:57:34 AM
Update 20130920.

Extent: +34k9 (+1498k vs 2012)
Area: +64k3 (+1524k vs 2012)

Extent increased especially in the CAA. The CAA seems to be filling up weeks ahead of last year. That is not visible in the other regions yet. Today the ESS and CAB had smaller extent growth, in other regions it is quiet.

 
You will find the updated graphs in the top post (https://forum.arctic-sea-ice.net/index.php/topic,382.0.html)

The details (in 1000 km2):


Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                    5.2                     9.6                    -0.5
               Kara Sea             Barents Sea           Greenland Sea
                   -1.8                     0.1                    -2.9
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                    2.0                     0.0                    -0.1
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   14.9                     4.5                     4.0
             Bering Sea          Sea of Okhotsk            Total Extent
                    0.0                     0.0                    34.9

Area:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   22.1                     8.6                    -0.2
               Kara Sea             Barents Sea           Greenland Sea
                    0.4                     0.1                     3.0
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                    2.0                     0.0                     0.0
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   19.2                     4.8                     4.3
             Bering Sea          Sea of Okhotsk              Total Area
                    0.0                     0.0                    64.3

Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on September 21, 2013, 08:08:37 AM
The Beaufort did not melt out this year as it did in 2012. In the last week the ice has not changed much in total. But the changes map of the last week shows that the ice edge advanced in the west but in the eastern corner the gap between Banks island and the ice increased big way.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: jdallen on September 21, 2013, 08:42:32 AM
The Beaufort did not melt out this year as it did in 2012. In the last week the ice has not changed much in total. But the changes map of the last week shows that the ice edge advanced in the west but in the eastern corner the gap between Banks island and the ice increased big way.

At this point, a bowl of ice cubes sloshing around.  It will be interesting to see how long it takes for the ice to recover some coherence.  Might be good to try to identify some identifiable patterns to track movement later on in the season.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on September 22, 2013, 08:37:03 AM
Update 20130921.

Extent: +61.5 (+1512k vs 2012)
Area: +89.8 (+1565k vs 2012)

Big refreeze in the ESS today. The CAA continues to increase.
 
You will find the updated graphs in the top post (https://forum.arctic-sea-ice.net/index.php/topic,382.0.html)

The details (in 1000 km2):


Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                    5.2                    36.5                     0.2
               Kara Sea             Barents Sea           Greenland Sea
                    0.2                     0.1                    -9.2
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                    2.8                     0.0                     0.5
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   18.9                     1.3                     4.6
             Bering Sea          Sea of Okhotsk            Total Extent
                    0.1                     0.0                    61.5

Area:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   41.7                    43.0                     0.2
               Kara Sea             Barents Sea           Greenland Sea
                    0.4                     0.1                   -14.2
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                    3.5                     0.0                     0.3
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   10.5                     0.8                     3.5
             Bering Sea          Sea of Okhotsk              Total Area
                    0.1                     0.0                    89.8

Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on September 22, 2013, 08:47:33 AM
The ice edge in the East Siberian Sea is expanding everywhere.

Image attached: log in to see.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on September 23, 2013, 06:55:10 AM
Update 20130922.

Extent: +13k4 (+1442k vs 2012)
Area: -5k8 (+1467k vs 2012)

The growth in the ESS continues. Also the CAB extent did have a big increase. Declines in the CAA and Beaufort moderate the total increase.
 
You will find the updated graphs in the top post (https://forum.arctic-sea-ice.net/index.php/topic,382.0.html)

The details (in 1000 km2):


Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   19.5                    27.4                    -0.6
               Kara Sea             Barents Sea           Greenland Sea
                   -5.2                    -0.5                    -2.5
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                    2.9                     0.0                     0.6
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                  -20.3                    -9.5                     1.9
             Bering Sea          Sea of Okhotsk            Total Extent
                   -0.1                     0.0                    13.4

Area:
           Arctic Basin       East Siberian Sea              Laptev Sea
                    4.7                    20.3                    -0.4
               Kara Sea             Barents Sea           Greenland Sea
                   -2.5                    -0.3                    -0.7
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                    2.8                     0.0                     0.5
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                  -22.1                   -10.0                     2.0
             Bering Sea          Sea of Okhotsk              Total Area
                   -0.1                     0.0                    -5.8

Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on September 23, 2013, 07:12:26 AM
Autumn equinox 2013: ice increase on the Siberian side and declines in Beaufort, CAA and towards the Atlantic. The area of the Barents Bite is still clearly visible.

(attached, must log in to see)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on September 24, 2013, 11:05:27 AM
Update 20130923.

Extent: +28k4 (+1431k vs 2012)
Area: +25k7 (+1434k vs 2012)

Continuing the pattern of the day before: sea ice increased in the ESS and the CAB. A decline is noted in the CAA.
 
You will find the updated graphs in the top post (https://forum.arctic-sea-ice.net/index.php/topic,382.0.html)

The details (in 1000 km2):


Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   13.8                    16.0                    -0.1
               Kara Sea             Barents Sea           Greenland Sea
                    0.4                     0.0                    -2.1
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                    3.8                     0.0                     2.3
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                  -12.3                     4.6                     2.0
             Bering Sea          Sea of Okhotsk            Total Extent
                    0.0                     0.0                    28.4

Area:
           Arctic Basin       East Siberian Sea              Laptev Sea
                    5.9                     5.5                     0.0
               Kara Sea             Barents Sea           Greenland Sea
                    0.5                     0.0                   -17.8
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                    7.4                     0.0                     1.8
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                    7.6                    11.4                     3.4
             Bering Sea          Sea of Okhotsk              Total Area
                    0.0                     0.0                    25.7

Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on September 24, 2013, 11:18:22 AM
The edge of the ice pack is expanding along the Laptev and Kara sections of the CAB. But the concentration along that edge is quite low. Sign of divergence? May the movement reverse when the wind do the same?

(log in to see the attached images)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: jdallen on September 24, 2013, 05:39:47 PM
The edge of the ice pack is expanding along the Laptev and Kara sections of the CAB. But the concentration along that edge is quite low. Sign of divergence? May the movement reverse when the wind do the same?

(log in to see the attached images)

I have a hard time believing that is refreeze. Koeln shows temps across the region between 0 to minus 3C. Even at the low end, that's not enough for more than nilas. If there is any wind driven roughness, it's not even cold enough for that.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Jim Hunt on September 24, 2013, 06:20:20 PM
I have a hard time believing that is refreeze.

It doesn't look like "refreeze" to me either. See some recent Arctic art from my blue period for a visual impression of what's going on:

http://GreatWhiteCon.info/2013/09/central-arctic-art/ (http://GreatWhiteCon.info/2013/09/central-arctic-art/)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: jdallen on September 24, 2013, 06:46:58 PM
I have a hard time believing that is refreeze.

It doesn't look like "refreeze" to me either. See some recent Arctic art from my blue period for a visual impression of what's going on:


I remember that image... Very nice.  It looks like the "slush" we've talked about most of the season spreading out even more thinly. The ice equivalent of sea foam rafts one sees frequently just beyond the surf.

Edit: considering the apparent thickness and density of that stuff, and how we watched it melt out of areas like the Chukchi and Barents, another half a degree warmer water,  or slightly higher salinity, and that stuff would all melt out, possibly even now.  It affirms for me just how close by the "bullet" - serious melt out - passed by us this season.  How long will we stay lucky?
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on September 25, 2013, 06:58:23 AM
Update 20130924.

Extent: +58k0 (+1474k vs 2012)
Area: +63k7 (+1491k vs 2012)

The big increases are the ESS and the CAB, other regions are quiet or decline slightly (CAA).
 
You will find the updated graphs in the top post (https://forum.arctic-sea-ice.net/index.php/topic,382.0.html)

The details (in 1000 km2):


Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   29.6                    32.4                     0.8
               Kara Sea             Barents Sea           Greenland Sea
                    1.9                     0.0                    -4.4
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                    2.8                     0.0                     1.0
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   -5.4                    -0.4                    -0.3
             Bering Sea          Sea of Okhotsk            Total Extent
                    0.0                     0.0                    58.0

Area:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   35.3                    35.0                     0.5
               Kara Sea             Barents Sea           Greenland Sea
                    1.1                     0.0                     4.2
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                    1.9                     0.0                     0.7
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   -8.2                    -6.1                    -0.9
             Bering Sea          Sea of Okhotsk              Total Area
                    0.0                     0.0                    63.7

Title: Re: Home brew AMSR2 extent & area calculation
Post by: Bob Wallace on September 25, 2013, 06:59:53 AM
Quote
How long will we stay lucky?

2016 +/- 3


Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on September 25, 2013, 07:30:11 AM
Wind and wind-direction play a major role in the ice development at the moment. There is a broad wind field from the Canadian islands to Siberia. This causes the ice pack to move off the islands leaving crakcs with low concentration ice and open water above Prince Patrick Island. The existing gap above Banks keeps widening.

(log in to see attached image)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on September 26, 2013, 07:00:36 AM
Update 20130925.

Extent: +79k4 (+1524k vs 2012)
Area: +70k5 (+1493k vs 2012)

Continuing steep increase in the ESS and CAB, quiet elsewhere.
 
You will find the updated graphs in the top post (https://forum.arctic-sea-ice.net/index.php/topic,382.0.html)

The details (in 1000 km2):


Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   29.5                    46.9                     0.2
               Kara Sea             Barents Sea           Greenland Sea
                    3.4                     0.0                     1.6
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                    0.5                     0.0                    -1.7
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                    7.9                    -4.0                    -4.7
             Bering Sea          Sea of Okhotsk            Total Extent
                    0.0                     0.0                    79.4

Area:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   36.7                    34.4                     0.1
               Kara Sea             Barents Sea           Greenland Sea
                    0.9                     0.0                     0.9
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -0.1                     0.0                    -1.1
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                    9.2                    -7.0                    -3.6
             Bering Sea          Sea of Okhotsk              Total Area
                    0.0                     0.0                    70.5

Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on September 26, 2013, 07:35:09 AM
A small cyclone lies over the Chukchi Sea, causing the ice edge retreat facing Barrow and expanding further to the west. A number of parallel leads are developing. In the ESS, the ice is appearing on the shores of Novaya Sibir one of the New Siberian Islands.

(log in to see attached image)

 
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on September 27, 2013, 07:27:38 AM
Update 20130926.

Extent: +32k8 (+1518k vs 2012)
Area: +47k9 (+1507k vs 2012)

More of the same: significant CAB and ESS increases, small changes in the other regions.
I have been expecting and watching for some time for an increase in the Greenland Sea. Little is happening there yet.
 
You will find the updated graphs in the top post (https://forum.arctic-sea-ice.net/index.php/topic,382.0.html)

The details (in 1000 km2):


Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   31.6                    15.1                     1.2
               Kara Sea             Barents Sea           Greenland Sea
                   -0.1                     0.0                    -2.7
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                    2.6                     0.0                     0.3
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   -7.1                    -4.4                    -3.5
             Bering Sea          Sea of Okhotsk            Total Extent
                    0.0                     0.0                    32.8

Area:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   45.7                    22.4                     1.0
               Kara Sea             Barents Sea           Greenland Sea
                   -0.6                     0.0                   -12.2
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                    3.9                     0.0                     0.4
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   -3.0                    -6.6                    -3.0
             Bering Sea          Sea of Okhotsk              Total Area
                    0.0                     0.0                    47.9

Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on September 27, 2013, 07:45:38 AM
When winds came from the north we observed ice from the CAB to enter the channels and strait of the Canadian Archipelago. Now the winds are from the south and cracks between the CAB and the CAA  develop and widen. The McClure Strait has not looked so navigable this season.

(image is attached, log in to see)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on September 27, 2013, 07:53:59 AM
Too many interesting details today. How about these cracks/leads in the East Siberian Sea?

(log in etc)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: jdallen on September 27, 2013, 08:35:54 AM
Too many interesting details today. How about these cracks/leads in the East Siberian Sea?

(log in etc)

"Leads" implies splits in mostly contiguous stretches of ice.  In the region highlighted, I believe that is in rather short supply  ;D

More like gaps in flotsam rafts being opened up by the movement of waves.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Jim Hunt on September 27, 2013, 09:56:23 AM
It's a bit cloudy this morning, but a visual impression of some of those "leads" courtesy of Aqua/Worldview (https://earthdata.nasa.gov/labs/worldview/?map=-504672,961920,-95840,1227904&products=baselayers,MODIS_Aqua_CorrectedReflectance_TrueColor~overlays,arctic_graticule_3413,arctic_coastlines_3413&time=2013-09-27&switch=arctic):

Title: Re: Home brew AMSR2 extent & area calculation
Post by: jdallen on September 27, 2013, 07:27:55 PM
It's a bit cloudy this morning, but a visual impression of some of those "leads"

Looks like a few actually qualify for the definition. 

I continue to be fascinated by the low altitude cloud trains, which seem to be a signatuture feature of this season. They continue to be a moderating factor I suspect, which may reduce the initial strength of the refreeze as much as it retarded the summer melt.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Shared Humanity on September 27, 2013, 09:04:18 PM
I have only been here through 2 seasons but doesn't it seem we are dealing with a level of ice pack mobility never before seen? The winds seem to be pushing the ice all over the place.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on September 28, 2013, 07:58:55 AM
No regular update from the Uni Hamburg source yet. Waiting ...
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Jim Hunt on September 28, 2013, 06:03:25 PM
The winds seem to be pushing the ice all over the place.

Whilst we wait to see what AMSR2 reveals, here's Terra's view today (https://earthdata.nasa.gov/labs/worldview/?map=-528327.970008,1008564.599641,-139975.970008,1274548.599641&products=baselayers,MODIS_Terra_CorrectedReflectance_TrueColor~overlays,arctic_graticule_3413,arctic_coastlines_3413&time=2013-09-28&switch=arctic). The same vicinity as yesterday, and still some thin clouds masking the movement of the ice:

Title: Re: Home brew AMSR2 extent & area calculation
Post by: Jim Hunt on September 29, 2013, 03:26:29 PM
Is it just me, or is ftp-projects.zmaw.de down completely at the moment?
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on September 29, 2013, 04:04:43 PM
Is it just me, or is ftp-projects.zmaw.de down completely at the moment?

I cannot connect either.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Jim Hunt on September 30, 2013, 11:10:23 PM
It's up and running again now. Nothing for the 28th at present, but the 29th is there.

P.S. Having now downloaded the 29th, there is no ice to be seen!
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on October 01, 2013, 07:40:59 AM
Update 20130930.

Extent: +272.4 (NA vs 2012)
Area: +190.4 (NA vs 2012)

Since data for Sep28/29 is missing all changes are from Sep27,  three days difference.

Huge increases, and possible a first century this season. Most of the growth In the ESS, Laptev and CAB.

 
You will find the updated graphs in the top post (https://forum.arctic-sea-ice.net/index.php/topic,382.0.html)

The details (in 1000 km2):


Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   57.7                    84.8                    49.5
               Kara Sea             Barents Sea           Greenland Sea
                   21.0                     0.1                    -3.6
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                    1.7                     0.0                    -1.6
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   15.7                    21.8                    25.2
             Bering Sea          Sea of Okhotsk            Total Extent
                    0.0                     0.0                   272.4

Area:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   65.7                    51.4                    32.2
               Kara Sea             Barents Sea           Greenland Sea
                   11.8                     0.1                     1.0
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -2.2                     0.0                    -1.3
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                    5.0                    17.5                     9.1
             Bering Sea          Sea of Okhotsk              Total Area
                    0.0                     0.0                   190.4



[Update: new data for Sep 27, 28 and 29 was put on the server today. So much changed, that I need to put the correct data below. Still everything is over the last three days.]

Extent: +192k9 (+1651k vs 2012)
Area: +159k9 (+1555k vs 2012)

Huge increases, and possible a first century this season. Most of the growth In the ESS, Laptev and CAB.

You will find the updated graphs in the top post (https://forum.arctic-sea-ice.net/index.php/topic,382.0.html)

The details (in 1000 km2):


Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   47.7                    78.3                    35.0
               Kara Sea             Barents Sea           Greenland Sea
                   15.6                     0.0                   -11.4
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -1.4                     0.0                    -1.7
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                    0.3                    15.4                    15.2
             Bering Sea          Sea of Okhotsk            Total Extent
                    0.0                     0.0                   192.9

Area:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   62.1                    49.4                    26.6
               Kara Sea             Barents Sea           Greenland Sea
                    9.9                     0.0                    -2.4
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -3.8                     0.0                    -1.4
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   -1.9                    15.3                     6.1
             Bering Sea          Sea of Okhotsk              Total Area
                    0.0                     0.0                   159.9

Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on October 01, 2013, 07:59:33 AM
This section with the ESS and Laptev Sea show a mix of wind driven diversion and refreeze. Low pressure north of the New Siberian Islands cause winds drive most of the ice movements.
Ice growth along the shores and in the direction of Chukchi looks like freezing.

(The graphic represents a 3 day change. It can only be seen when logged in)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: jdallen on October 01, 2013, 08:36:48 AM
This section with the ESS and Laptev Sea show a mix of wind driven diversion and refreeze. Low pressure north of the New Siberian Islands cause winds drive most of the ice movements.
Ice growth along the shores and in the direction of Chukchi looks like freezing.

(The graphic represents a 3 day change. It can only be seen when logged in)

I agree with you as regards the pack, but I still think the coastal air temperatures are too high for a refreeze there.  The only way I could see it if you had fresh water ice being swept out of river estuaries.  Even then, I think the interior temperatures are still far too high.

Add this to it:

http://polar.ncep.noaa.gov/sst/ophi/color_sst_NPS_ophi0.png (http://polar.ncep.noaa.gov/sst/ophi/color_sst_NPS_ophi0.png)

... which suggests that the water is still far to warm as well.  I think the satellites are being fooled by atmospheric moisture.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on October 01, 2013, 09:04:04 AM
... which suggests that the water is still far to warm as well.  I think the satellites are being fooled by atmospheric moisture.

Thanks, I am not 100% convinced either. But the "coastal ice" is also visible on Jaxa's ice concentration calculation. That is other sensors and other algorithms, less sensitive to water vapor.

If somebody can have a look at the visible spectrum (MODIS) images?
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on October 01, 2013, 09:51:02 AM
It is October, summer is definitely over. I think it is time to stop the daily detailed report. Less frequent observations will of course continue, as well as daily updates of the graphs.

This will give room to make changes to the processing that would have been too disruptive to do in the melting season:
- I am not happy with some aspects of the pole hole handling (must handle polar polynya) , the coastal ice removal (a bit too aggressive) and the phantom ice removal (too aggressive sometimes);
-a software rewrite needed for cleaning, performance and maintainability. Most likely this will involve Python;
-research will have to be done to create homogeneous time series by adding available SSMI/SSMIS/AMSR-E data to that from the AMSR2;
-I really have to do some work on the web pages;
-some more ideas, to vague now to mention.

As always, I am open to all suggestions and wishes for improvements that make this effort more useful.

Alexander Beitsch from Uni Hamburg wrote to me that he intends to reprocess the whole AMSR2 series, with new improvements. Thanks to Alexander for waiting until the melting season is over, but also for data that I think has already showed to be of great quality and of awesome beautiful resolution.

Anyway watch this space for reports on development of things.

Thanks for watching until now and all the supportive comments.
 
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Jim Hunt on October 01, 2013, 10:09:26 AM
If somebody can have a look at the visible spectrum (MODIS) images?

It's all rather cloudy, but I can't see any ice near the coast. Worldview does reveal (https://earthdata.nasa.gov/labs/worldview/?map=-1437944.970573,1241277.656858,-946424.970573,1514941.656858&products=baselayers,MODIS_Terra_CorrectedReflectance_Bands721~overlays,arctic_graticule_3413,arctic_coastlines_3413&time=2013-10-01&switch=arctic) this view of the fresh ice extending out towards Wrangel Island:

Title: Re: Home brew AMSR2 extent & area calculation
Post by: Jim Hunt on October 01, 2013, 10:18:50 AM
Maybe there's a hint of something here?
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Tor Bejnar on October 01, 2013, 05:02:44 PM
Quote
I am not happy with some aspects of the pole hole handling (must handle polar polynya)
Wipneus,
Might MODIS get incorporated into a Pole Hole fix somehow?  When the NP is cloud-free, good SIA/SIE numbers can be obtained for the Pole Hole.  Subsequent cloudy days can have NP ice extrapolated using "last known MODIS SIA/SIE" and changing Pole Hole rim SIA/SIE. 

After a couple of weeks without new NP MODIS data, a system using MODIS might be no better than one using only Pole Hole rim data.  An algorithm could be written to account for this.

One problem with this approach may be that clear NP weather (high pressure likely) will support melt or spreading while subsequent cloudy weather (low pressure likely) will support compaction.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on October 01, 2013, 06:21:33 PM

Might MODIS get incorporated into a Pole Hole fix somehow? 


I was not aiming that high yet. For the moment I am satisfied with a calculation that lets the extent and area of the pole hole go from 100% to 0% with the ice around the pole hole going from 100% to ice-free.

In comparison, NSIDC and Jaxa both assume the pole hole extent to be 100%. If the whole Arctic becomes ice-free, there is still ice in the pole hole. In my current calculation, area is fine but extent will jump from 100% to zero when the calculated concentration becomes less than 15%.

Comparing with ice free MODIS images is definitely interesting. 
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Bob Wallace on October 01, 2013, 06:57:52 PM
Quote
I think it is time to stop the daily detailed report.

I agree, less frequent updates will be fine for now.

Thanks so much for your work.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: jdallen on October 01, 2013, 07:07:25 PM
Maybe there's a hint of something here?

Zooming in, Looks like low level cloudiness to me.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on October 01, 2013, 07:22:14 PM
New data for Sep 27, 28 and 29 was put on the server today. So much changed that I updated the report for 20130930. No longer any possibility for century increases.

Actually here are the daily extent changes for Sep 27-30 (1000 km2):
 49.9 79.5 33.8 79.6

and area:
 72.2 87.2 32.5 40.2
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Lennart van der Linde on October 01, 2013, 07:30:45 PM
Wipneus, thanks for all the great work!
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Neven on October 01, 2013, 08:43:11 PM
Quote
I think it is time to stop the daily detailed report.

I agree, less frequent updates will be fine for now.

Thanks so much for your work.

Yes, thanks a lot, Wipneus!
Title: Re: Home brew AMSR2 extent & area calculation
Post by: ChrisReynolds on October 01, 2013, 09:02:07 PM
Yep, thanks and well done Wipneus.

From my work on PIOMAS gridded data I appreciate how much hard work you've done on this, perhaps more than most.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Jim Hunt on October 01, 2013, 09:37:00 PM
A vote of thanks from me too. Three cheers for Wipneus!

I don't know if this has been mentioned elsewhere, but I've just discovered that your name has been taken in vain by both the BBC and the Polar Science Center!

BBC article incorrectly attributes predictions of imminent sea ice loss to University of Washington (http://psc.apl.washington.edu/wordpress/bbc-article-incorrectly-attributes-predictions-of-sea-ice-loss-to-universtiy-of-washington/)

Quote
This analysis extrapolates PIOMAS ice volume data to arrive at a date when sea ice might first disappear. This extrapolation represents the analysis and judgement of the unidentified poster of the graph.
 
The Arctic Sea Ice Blog  provides an interesting discussion on the sourcing of the extrapolation
Title: Re: Home brew AMSR2 extent & area calculation
Post by: johnm33 on October 02, 2013, 12:24:35 AM
Great work Wipneus much appreciated thank you.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on October 02, 2013, 08:25:34 AM
Thank you people for all the kind words.

I wouldn't do this if I did not enjoy it. Even refreezing can give some nice pictures.

(attached animation can be seen when logged in. Click on it if it does not "animate")
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Lennart van der Linde on October 02, 2013, 04:37:37 PM
Is that Bobby? Where's Kuifje (Tintin)?
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Jim Hunt on October 02, 2013, 04:47:10 PM
Perhaps appropriately in all the circumstances, he was called Snowy (http://en.wikipedia.org/wiki/Snowy_%28character%29) during my childhood here in South West England.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: TeaPotty on October 03, 2013, 02:45:10 AM
Wipneus, I have learned so much from reading your posts  ;D
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on October 03, 2013, 09:11:56 AM
Waiting for the first century and then you get this:

Extent: -40k9 (+1531k vs 2012)
Area: -33k6 (+1430k vs 2012)


It is along the ice edge and in the CAA. I did not check, but the winds must have changed.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Espen on October 03, 2013, 09:29:56 AM
I believe the polar bears in Svalbard must be starving, and there is no sea ice in sight?
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on October 03, 2013, 11:15:10 AM
No, and the ice edge is not moving to Svalbard at all. The Fram Strait transport is minimal.

(animation attached, log in and click if it does not "animate")
Title: Re: Home brew AMSR2 extent & area calculation
Post by: LarsBoelen on October 03, 2013, 11:13:28 PM
Thanks for all your work on this thread this summer, I appreciate how much work it is as I tried to do a daily update of my melt-movie.

I wonder, Wipneus, if climate-historians will pinpoint 2013 as "the year Fram Straight export stopped".
I'm way to new to this subject to substantiate this, but from "movies" i've seen of other years, I can't remember such a complete shutdown of the export.

Time to start reading on the impact on weather systems of sea ice on the east coast of Greenland.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on October 04, 2013, 07:51:23 AM
Lars, Greenland Sea ice area has been low, even lower, before (http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/recent365.anom.region.5.html)

So I expect the low 2013 Fram Strait transport is not unique.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Jim Hunt on October 04, 2013, 02:07:20 PM
Zooming in, Looks like low level cloudiness to me.

There's a much clearer view (https://earthdata.nasa.gov/labs/worldview/?map=-1195744,1840755.213657,-730080,2081907.213657&products=baselayers,MODIS_Terra_CorrectedReflectance_Bands367~overlays,arctic_graticule_3413,arctic_coastlines_3413&time=2013-10-04&switch=arctic) today, and zooming in it now looks like newly nascent ice to me!

P.S. I can't see your latest animation Wipneus?
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on October 04, 2013, 02:53:57 PM
P.S. I can't see your latest animation Wipneus?

Oops, it did not get attached. Unfortunately I can not fix this right now, it will have to wait until tomorrow late.

Sorry about that.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: ChrisReynolds on October 04, 2013, 06:22:46 PM
I believe the polar bears in Svalbard must be starving, and there is no sea ice in sight?

Heartbreaking indeed, poor monsters.  :'(
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Laurent on October 04, 2013, 09:41:35 PM
Here is a real monster !
Deadly giant hornets kill 42 people in China 1500 injured (http://www.youtube.com/watch?v=FPQuth6jk68#)
Well...monster...it is a bit to much...poor bears !
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on October 05, 2013, 03:50:15 PM
Let me try that again.

In this animation winds have turned from north to south three times, creating a crack with open water north of the Canadian Archipelago.

(after logging in click on the image to make it animate)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on October 05, 2013, 03:52:42 PM
First century of 2013/2014 season:

Extent: +122k6 (+1675k vs 2012)
Area: +81k2 (+1477k vs 2012)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on October 08, 2013, 08:49:47 AM
Refreezing continues with century/day speed. The epicenter is still the East Siberian Sea where the ice advances from the the Arctic central pack as well as from the coast.
Today, southern winds are blowing the coastal ice away from the shore but cannot prevent continuing freezing from the "edge".

(log in to see attached image)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on October 11, 2013, 09:06:21 AM
Extent is now more than 2Meg over 2012:


Extent: +159k1 (+2028k vs 2012)
Area: +179k8 (+1854k vs 2012)


Fram Strait transport is still low, but that may change soon as some concentric cracks in the ice pack to the north show.

(need to log in, click on the image for an animation)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Phil. on October 12, 2013, 07:17:28 AM
Extent is now more than 2Meg over 2012:


Extent: +159k1 (+2028k vs 2012)
Area: +179k8 (+1854k vs 2012)


Fram Strait transport is still low, but that may change soon as some concentric cracks in the ice pack to the north show.

(need to log in, click on the image for an animation)

I notice that the Pole cams have finally started to drift south after being stubbornly stuck at 84ºN for a while.  Perhaps they're finally going to emerge from the Strait.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on October 12, 2013, 09:14:44 AM
Changes in 1 week, Oct 04 to Oct 11:

Extent: +912k2 (+2086k vs 2012)
Area: +943k4 (+1918k vs 2012)

The map shows freezing from the CAB outward, except to the Beaufort.

(log in to see attached image)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on October 14, 2013, 11:54:10 AM
Lots of ice on the move in this part of the Canadian Archipelago.

(login and click to see attached image)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Shared Humanity on October 14, 2013, 04:43:29 PM
Lots of ice on the move in this part of the Canadian Archipelago.

(login and click to see attached image)

I cannot shake the feeling that we have transitioned to a new phase state in the Arctic. This new state is characterized by dramatic sea ice mobility. With less MYI, land fast ice and mass, the sea ice is much more reactive to weather in the arctic.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on October 16, 2013, 09:35:33 AM
The East Siberian Sea has an almost 100% ice cover by extent, Laptev will follow very soon. It is mostly new ice of course with lots of mobility.

(login and click on the picture to see the animation)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on October 25, 2013, 06:56:30 AM
Baffin Bay is starting to fill seriously with sea ice. In the center of the animation the parked remnants of PII iceberg are visible. Also watch the "whirl pool" at the entrance of Parry Channel.

(log in and click on attached image to animate)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: ggelsrinc on October 25, 2013, 09:03:18 AM
Baffin Bay is starting to fill seriously with sea ice. In the center of the animation the parked remnants of PII iceberg are visible. Also watch the "whirl pool" at the entrance of Parry Channel.

(log in and click on attached image to animate)

I see a problem in what I perceive as those CAA flow rates in that animation. The fast flows at Nares are to be expected, but contrary to some people, I've suspected the last of the ASI will exist in the CAA, AB and not north of Greenland near it's coast, where Fram and Nares can take it, based on my analysis of recent ocean currents. I remember being told by people who lived in Canada about the conditions of MYI in the CAA. In my mind's eye, MYI can only exist within a certain neighborhood and ASI going south of CAA is either doomed or lucky enough to get stuck for awhile clogging the pipes that will remove it. I would hope the pipes would be clogged at this late of a time in the year, regardless of weather and the Arctic not be losing any MYI. It's not something easy to replace it. 

This is only the second year I've examined the refreeze in some detail, but last year I remember the gyre direction taking MYI away from CAA. I still can't find that Navy Arctic data to get a better picture. I guess paying a University a few pennies to do cheap work for the government is just too costly. <grumble>

Wipneus, is the export of ASI I'm seeing normal to the Arctic at this time of year in that area?   
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on October 25, 2013, 09:41:37 AM
Quote
Wipneus, is the export of ASI I'm seeing normal to the Arctic at this time of year in that area? 

The ice is still very mobile, and the influence of the winds can be observed everywhere. So I don't think this is unusual, especially in recent years.
The resolution and quality of the AMSR2 makes this much easier to follow, unfortunately it is not so easy to compare with previous years.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Andreas T on October 25, 2013, 12:15:16 PM
wipneus, some features in the animation seem to disappear and reappear, is that a result of changing ice reflectivity / thickness or problems caused by cloudcover? I also noticed that on the animation you posted in the Nares Strait thread where visibility of PII was much reduced in some frames.   It is of course great to see these animations and it would be foolish to expect the kind of resolution of clear sky visisble or IR images, but I am trying to learn how to "read" what I see.
Thank you very much for the work you do!
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Jim Hunt on October 25, 2013, 02:03:01 PM
The ice is still very mobile, and the influence of the winds can be observed everywhere.

Certainly not easy to compare with previous years, but ice mass balance buoy 2013C (http://batchgeo.com/map/imb-2013c) has been very mobile recently. It now seems to be whizzing around in "the 'whirl pool' at the entrance of Parry Channel":
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on October 26, 2013, 08:20:56 AM
wipneus, some features in the animation seem to disappear and reappear, is that a result of changing ice reflectivity / thickness or problems caused by cloudcover? I also noticed that on the animation you posted in the Nares Strait thread where visibility of PII was much reduced in some frames.   It is of course great to see these animations and it would be foolish to expect the kind of resolution of clear sky visisble or IR images, but I am trying to learn how to "read" what I see.
Thank you very much for the work you do!

Change reflectivity by emissivity, as these instruments measure thermal microwave emission of ice and water. Fortunately in the microwave bands used by the ASI algorithm, the emissivity is not very variable (which is not so true for other algorithms).

Liquid water in cloud and water vapor certainly influence the results. There is another factor affecting the PII iceberg(s), that is movement. The satellite makes multiple passes over the iceberg each day, and I presume the final pixels are an average of these passes. When the iceberg is moving sufficiently fast, the apparent brightness is reduced.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: ggelsrinc on October 26, 2013, 11:25:25 AM
wipneus, some features in the animation seem to disappear and reappear, is that a result of changing ice reflectivity / thickness or problems caused by cloudcover? I also noticed that on the animation you posted in the Nares Strait thread where visibility of PII was much reduced in some frames.   It is of course great to see these animations and it would be foolish to expect the kind of resolution of clear sky visisble or IR images, but I am trying to learn how to "read" what I see.
Thank you very much for the work you do!

Change reflectivity by emissivity, as these instruments measure thermal microwave emission of ice and water. Fortunately in the microwave bands used by the ASI algorithm, the emissivity is not very variable (which is not so true for other algorithms).

Liquid water in cloud and water vapor certainly influence the results. There is another factor affecting the PII iceberg(s), that is movement. The satellite makes multiple passes over the iceberg each day, and I presume the final pixels are an average of these passes. When the iceberg is moving sufficiently fast, the apparent brightness is reduced.

I tried to find information on salinity of ASI following the fragmentation event, with limited success. Do you or does anyone having knowledge, know of studies to measure the tensile stress of ASI, or just sea ice in general? Concept:

http://en.wikipedia.org/wiki/Tensile_strength (http://en.wikipedia.org/wiki/Tensile_strength)

Atlas was complaining about his back hurting again today and he wants to know.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Jim Hunt on October 26, 2013, 12:19:52 PM
Do you or does anyone having knowledge, know of studies to measure the tensile stress of ASI, or just sea ice in general? Concept:

The conventional wisdom is that you should be looking here first:

http://en.wikipedia.org/wiki/Rheology (http://en.wikipedia.org/wiki/Rheology)

I have a little book on this sort of stuff - "Drift, Deformation, and Fracture of Sea Ice: A Perspective Across Scales (http://www.amazon.co.uk/Drift-Deformation-Fracture-Sea-SpringerBriefs/dp/9400762011)" by Jerome Weiss

It includes many references, the vast majority of which I haven't read! If you can be a bit more specific maybe I can suggest something? Part of the concluding chapter says:

Quote
Brittle rheology implies a strongly non-linear response of sea ice to mechanical forcing, with the consequence of reinforcing the intermittency and spatial localization, and modifying the scaling properties.

together with:

Quote
The failure strength of the ice cover depends linearly on its thickness. consequently a thinner ice cover will break up and crumble more easily for the same wind/current mechanical forcing.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Andreas T on October 26, 2013, 08:47:18 PM
Thank you, Wipneus, could you point me (and others) to a place to read up on AMSR2?
This, I guess, reinforces your point about mobility of the ice:
 http://ocean.dmi.dk/arctic/images/MODIS/MorrisJessup/201310260353.NOAA.jpg (http://ocean.dmi.dk/arctic/images/MODIS/MorrisJessup/201310260353.NOAA.jpg) in conjunction with Ice Speed and Drift from the graphs page (what is the name under which I should refer to it? CICE? ARC? HYCOM? not sure how to link). I interpret that as older ice from north of Greenland heading for the Fram Strait drain, increasing extent now but will be figuring as a volume loss in 2014.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: ggelsrinc on October 26, 2013, 10:40:21 PM
Do you or does anyone having knowledge, know of studies to measure the tensile stress of ASI, or just sea ice in general? Concept:

The conventional wisdom is that you should be looking here first:

http://en.wikipedia.org/wiki/Rheology (http://en.wikipedia.org/wiki/Rheology)

I have a little book on this sort of stuff - "Drift, Deformation, and Fracture of Sea Ice: A Perspective Across Scales (http://www.amazon.co.uk/Drift-Deformation-Fracture-Sea-SpringerBriefs/dp/9400762011)" by Jerome Weiss

It includes many references, the vast majority of which I haven't read! If you can be a bit more specific maybe I can suggest something? Part of the concluding chapter says:

Quote
Brittle rheology implies a strongly non-linear response of sea ice to mechanical forcing, with the consequence of reinforcing the intermittency and spatial localization, and modifying the scaling properties.

together with:

Quote
The failure strength of the ice cover depends linearly on its thickness. consequently a thinner ice cover will break up and crumble more easily for the same wind/current mechanical forcing.

I have a solid background in rheology, including working on the development of the world's most sensitive rheometer, many years ago. It is true that materials like ice and glass have fluid properties, but they also have properties like tensile strength that can be measured like solids. My experience in that field is somewhat limited to metals.

Using the word stress instead of strength was a poor choice and was confusing.

In simple English, has testing of sea ice been accomplished to determine it's strength under various conditions of formation? My reasons for wondering about such details is trying to assess how sea ice will handle the changes it's future will subject it to.

Various governments have an interest in an ice free Arctic, but I don't share their concerns. I'm more concerned about the canary being removed from the coal mine and blocking it's entrance.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Andreas T on October 27, 2013, 03:01:57 AM

looking at http://ocean.dmi.dk/arctic/images/MODIS/Joekelbugt/201310250624.NOAA.jpg (http://ocean.dmi.dk/arctic/images/MODIS/Joekelbugt/201310250624.NOAA.jpg) it seems that the mobility of the ice has more to do with the rheology of solid / liquid two phase flow with variable grain size in two dimensions. Strength of the ice probably has an influence on size of floes, but most ice will not be uniform with frozen over leads and ridges. Only a good model which incorporates a lot of parameters which are based on previous conditions of the ice would be able to describe that.
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2F&hash=35d7d5d7526c9897dfb55501e320295a)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: ggelsrinc on October 27, 2013, 04:56:05 AM

looking at http://ocean.dmi.dk/arctic/images/MODIS/Joekelbugt/201310250624.NOAA.jpg (http://ocean.dmi.dk/arctic/images/MODIS/Joekelbugt/201310250624.NOAA.jpg) it seems that the mobility of the ice has more to do with the rheology of solid / liquid two phase flow with variable grain size in two dimensions. Strength of the ice probably has an influence on size of floes, but most ice will not be uniform with frozen over leads and ridges. Only a good model which incorporates a lot of parameters which are based on previous conditions of the ice would be able to describe that.
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2F&hash=35d7d5d7526c9897dfb55501e320295a)

and?

I wasn't looking for information on present sea ice floes and wanted information on sea ice tensile strength to form the basics of an understanding on how sea ice will respond to future weather conditions and make judgments about whether good or bad conditions are present during it's formation.

If I wanted to look at the materials of sea ice in these similar terms, I'd be looking at relative viscosity and not rheology, though the subjects are related to the point of being all inclusive, if someone has that perspective.

I seriously doubt if anything other than a government lab has investigated the sea ice based on tensile strength, because there isn't a profit motive involved in such research. My guess is such research was done in the past by our Navies putting nuclear submarines under that Arctic sea ice and other useful pre-satellite ASI information is archived as well.   
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Jim Hunt on October 27, 2013, 04:14:10 PM
We seem to be drifting further and further from AMSR2, but....

Andreas - I think the acronym you are looking for is ACNFS (Arctic Cap Nowcast/Forecast System). Is this the sort of image you were looking for? I've grabbed the GIF and attached it here since the direct links to the drift archives don't seem to be updating properly. The ones for thickness (http://www7320.nrlssc.navy.mil/hycomARC/navo/arc_list_arcticictn.html) seem be utilising some sort of time machine!

ggelsrinc - I'm no expert in these matters, but the emphasis in the past seems to have been on compression rather than tension. Does this paper from Weiss help at all?

"Sea ice rheology from in-situ, satellite and laboratory observations: Fracture and friction (http://www-lgge.obs.ujf-grenoble.fr/~weiss/publi/sea%20ice%20rheology.pdf)"
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Andreas T on October 27, 2013, 06:41:55 PM
Thank you, Jim, this conversation should definitely move into a seperate thread, I feel. Can the moderators do this, or do we need to stop and start again elsewhere?
 Tracking motion and moveability of the ice over the coming months seems worthwhile to me especially when considering the fragmented state of some of the ice which has survived the summer. The article talks about the behaviour of "perennial ice", looking at the ice age maps there are scattered crumbs of multiyear ice. I read the whiter specks in the IR images such as http://ocean.dmi.dk/arctic/images/MODIS/MorrisJessup/201310270342.NOAA.jpg (http://ocean.dmi.dk/arctic/images/MODIS/MorrisJessup/201310270342.NOAA.jpg)as such fragments with colder surfaces, is that correct? (you see I have taken your advice)
 In that state (before winter increases thickness of the "infill" substantially) it looks to me like the "granular plastic" material mentioned in the text you linked. Lots more to say but not here?
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Jim Hunt on October 28, 2013, 12:09:10 PM
This conversation should definitely move into a seperate thread, I feel.

I'm not sure if the moderators can move stuff or not. In the meantime I've started a new thread in which to continue (and if necessary restate) the conversation. Here it is:

"Drift, Deformation and Fracture of Sea Ice (http://forum.arctic-sea-ice.net/index.php/topic,624.0.html)"
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on October 31, 2013, 12:49:01 PM
A Fram export animation based Uni Hamburgs AMSR2 3.125 km ice concentration data.

Export is well on its way (but ice extent in the Greenland Sea is still behind 2012). Watch the vortices where the ice is moving south. More north, the edge between the ice pack and the Ocean is quite sharp, resembling a fluid surface held by gravity.

(click on attached image if it does not "animate")
Title: Re: Home brew AMSR2 extent & area calculation
Post by: jdallen on November 01, 2013, 09:18:45 AM
Thank you muchly for the image, Wipneus!

I'm betting part of the reason behind the sharp delineation may be northward-moving warm water that's still a couple of degrees above freezing.  That would tear apart the ice we see (probably much not more than a meter thick) at the rate of 5-10 CM/day.  If the flow doesn't have much of an E-W component to its movement, that might tend support the boundary we see, along with other factors like surface wind and current.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Andreas T on November 01, 2013, 09:54:13 PM
I am not sure how to interpret these patterns, but they do look wind driven to me.
source http://ocean.dmi.dk/arctic/nord.uk.php (http://ocean.dmi.dk/arctic/nord.uk.php)
The ice nearer the edge is moving southwards at a higher rate than that nearer the coast. That itself with faster movement further south could result in a thinning of the region near the edge, thereby stopping floes drifting towards the east.
That is the sort of thing I hope to discuss on Jim's new thread
"Drift, Deformation and Fracture of Sea Ice (http://forum.arctic-sea-ice.net/index.php/topic,624.0.html)"
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on November 03, 2013, 09:31:36 AM
Kara sea is where most of the ice increase has been in the past two weeks. It is also the region where the growth is more earlier than other regions, compared with the timeline in 2012.
The animation shows most of the growth is "in situ", but the northern winds that bring the cold also transport ice from the central pack.

(click on attached image if it does not "animate")
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Bob Wallace on November 03, 2013, 08:15:18 PM
Was PIOMAS volume data for September released - did I miss it?

Title: Re: Home brew AMSR2 extent & area calculation
Post by: Jim Hunt on November 03, 2013, 09:33:53 PM
Was PIOMAS volume data for September released - did I miss it?

You didn't miss a thing Bob. The Arctic Sea Ice Volume Anomaly (http://psc.apl.washington.edu/wordpress/research/projects/arctic-sea-ice-volume-anomaly/) page still says:

Quote
September Update Delayed:  Required data not available due to US Government shutdown.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Bob Wallace on November 03, 2013, 09:39:23 PM
Thanks.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Jim Hunt on November 05, 2013, 02:45:31 AM
Try my link again Bob. PIOMAS now seems to be back in action, and the September numbers are available at long last.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on November 08, 2013, 09:56:44 AM
The growth of sea ice seems to have "paused". In the last couple of days the ice most regions either retreated or at least stooped increasing. Only Baffin and Hudson kept increasing.

Attached image shows the "retreat" is mostly on the Atlantic side, particularly in the Kara sea.

(log in to see attached image)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on November 12, 2013, 09:05:19 AM
The filling of the Baffin Bay continues steadily. What surprised me in this animation is that the transport from the Nares Strait continues strongly. I have no idea when the blockade is supposed to start.

(click on the image if there is no animation)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: ggelsrinc on November 12, 2013, 11:43:20 AM
The filling of the Baffin Bay continues steadily. What surprised me in this animation is that the transport from the Nares Strait continues strongly. I have no idea when the blockade is supposed to start.

(click on the image if there is no animation)

Wipneus, I'm not trying to take your thread off topic, but I've been watching that and other similar areas for years, thinking what would it take to plug up those ASI transport leaks around this time of year. Your animation has inspired me again to speak my mind.

If I had the cooperation of two of my childhood heros, Dudley Do-Right and Hans Christian Andersen (and I mean no disrespect for the fine people of Canada and Denmark by my sloppy use of metaphor), I'd make an ice bridge to plug up that ASI transport. Cooperation with the Inuit people living in that area also needs to be considered.

The concept is simple enough, if nature can make an ice bridge, why can't we do it, but some of the methods I've considered are strange? I've pondered, is it possible to "borrow" a piece of Petermann glacier or some of the old Ellesmere ice shelf, rig it with sail and move it to plug up those ASI leaks? Is it possible to "weld" ice together using liquid nitrogen? What base of operation should we use, well Camp Century, of course?!

Now, I only put that in a question form to illustrate how your animations make people think of things as a function of time, when before it was static, lifeless data. There are better places to discuss these and other ideas, but I just wanted to say thanks again for your efforts and accomplishments. Even a humble warrior such as yourself is worthy of our praise. 
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Neven on November 12, 2013, 07:14:00 PM
The filling of the Baffin Bay continues steadily. What surprised me in this animation is that the transport from the Nares Strait continues strongly. I have no idea when the blockade is supposed to start.

Me neither. I'm sure Andreas Münchow does.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Andreas T on November 12, 2013, 10:45:39 PM
Wouldn't the answer to that question have to be found at the northern end of the strait?
here http://ocean.dmi.dk/arctic/images/MODIS/Lincoln/201311081308.NOAA.jpg
 (http://ocean.dmi.dk/arctic/images/MODIS/Lincoln/201311081308.NOAA.jpg) is a clear sky view from Friday.
If Andreas Münchow does comment on this, I would like to ask him whether his measurements of tides in Nares Strait http://icyseas.org/2013/10/24/ruins-of-fort-conger-in-the-high-arctic/ (http://icyseas.org/2013/10/24/ruins-of-fort-conger-in-the-high-arctic/) suggest a role of tidal movement in breaking ice at the northern entrance?
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Andreas Muenchow on November 13, 2013, 01:16:13 AM
The filling of the Baffin Bay continues steadily. What surprised me in this animation is that the transport from the Nares Strait continues strongly. I have no idea when the blockade is supposed to start.

Me neither. I'm sure Andreas Münchow does.

Fun discussion and animations ;-)

The ice-bridge or ice-arch across Smith Sound separating Nares Strait from Baffin Bay forms generally somewhere between November and February of each year. Last year it was extremely early, because Petermann's 200-m thick, grounded ice island partially anchored the bridge. There were years in the 2006-2009 timeframe (I'd have to look up the numbers and dates) when no ice-arch formed in Smith Sound.

It appears to me, that the Smith Sound ice-arch is always preceeded by an ice-arch at the northern entrance to Nares Strait in the Lincoln Sea. That one appears to be forming right now, as thermal (MODIS) imagery shows the concentric rings of thinner (warmer) ice before it all compacts into a solid ice-plug. It showed most dramatic in 2009 when only the northern end was plugged and ice was thin and mobile all winter. [I have posted a complete 2000-present set of daily Nares Strait thermal MODIS imagery, if someone wants to dig in.]

Tidal currents are weak (less than 1/2 kts amplitude) in the north, however, they are much larger in the south of Nares Strait (more than 1 kts), so the southern ice-arch (or ice-plug) forms preferentially near neap-tide. And yes, tensile strength of the ice has something to do with, too, but tensile strength is temperature dependent and a group of floes has different tensile properties than does an individual piece of ice (I know nothing of ice and rheology, so take this with a grain of salt). The ice in Nares Strait is always a melange of vastly different types of ice and, I believe, the fraction of thicker multi-year to thinner first-year to thinner-yet new ice may matter also in when and how this melange congeal into a solid mass that blocks all ice motion for months.

Gothic cathedrals and their stability characteristics come to mind, e.g., http://icyseas.org/2012/06/11/ice-arches-and-gothic-cathedrals/ (http://icyseas.org/2012/06/11/ice-arches-and-gothic-cathedrals/)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on November 21, 2013, 09:34:38 AM
Werther (https://forum.arctic-sea-ice.net/index.php/topic,92.msg17093.html#msg17093) pointed yesterday to the region North of Svalbard/Frantsa Yosefa. High (anomalous) temperatures IIRRC. Indeed there is an impressive darkening in the Ice concentration to be seen. If I didn't know better, I's suggest surface melting there.
Ice is continuing exported through the Fram.

(click on the attached image for an animation)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: jdallen on November 21, 2013, 06:10:44 PM
Werther pointed yesterday to the region North of Svalbard/Frantsa Yosefa. High (anomalous) temperatures IIRRC. Indeed there is an impressive darkening in the Ice concentration to be seen. If I didn't know better, I's suggest surface melting there.
Ice is continuing exported through the Fram.

(click on the attached image for an animation)

That... Is just SO wrong...

But it makes sense anecdotally when looking at atmospheric flow and surface temps.  The cold pole(s) are currently about 10-15 degrees south - in the CAA.  I was about to add Siberia, but temps there seem anomalously high as well.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on December 06, 2013, 08:55:15 AM
Baffin Bay, Nares Strait animation. The ice-arch can be seen forming and collapsing again. The north of Baffing Bay gets surprisingly ice free, even a remnant of PII iceberg can be seen by the keen observers.

(click on attached image if it does not animate)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on December 19, 2013, 07:08:27 AM
Nares Strait transport continues...
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on December 19, 2013, 07:21:54 AM
Hudson Bay has reached near 100% extent. The time is about normal as far as I know.

(click on the attached image if there is no animation)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: jdallen on December 20, 2013, 01:37:31 AM
Is it imagination on my part, or is the steady flow through Nares Strait anomalous? 

Seems like the Baffin refreeze is slow as well.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on December 21, 2013, 08:53:30 AM
Hudson bay is full, and as a consequence the increase of the Arctic Sea Ice has entered a "pause". A pause that happens about every year at this stage in the progression of the ice cover.

Most activity has since been in the Barentsz and the Bering Seas. They are opposite: the extent in the Barentsz  is a bit ahead than in 2012, but has been retreating these days. Even the ice North of Svalbard that was approaching the islands has been driven north.
In the Bering Sea, the ice has been slow this season, but it seems to be making up a bit.

(attached image can be seen only when logged in, click on it for a full view)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: jdallen on December 21, 2013, 09:11:41 AM
@wipneus - looks like a very bad year for polar bears on Svalbard...
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on December 26, 2013, 09:53:19 AM
The Gulf of st. Lawrence has not been discussed much, if at all, in this thread. If it was, it was often the false ice reported by the different instruments and algorithms. The lower resolution SSMIS sensors in combination with the NASA Team algorithm employed by the best known NSIDC sea ice data series are affected most by this problem.

But now increasing ice extent and area are even seen in the much higher resolution images from the AMSR2 instrument from Jaxa, either using their Bootstrap algorithm (10km resolution) or the ARTIST Sea Ice (ASI) algorithm with resolutions down to 3.125km.
There are still differences:

NSIDC SSMIS NASA Team 25km: ~70k extent
Uni Hamburg AMSR2 ASIv6 3.125km: ~14k extent
Jaxa AMSR2 Bootstrap 10km: ~21k extent

The attached image (click on it for the full view) shows the AMSR2 3.125 image with MODIS Terra close-ups over the st. Lawrence river created with the NASA Worldview tool. In the false color images ice and clouds are separated well. In the highest resolution ice floes can be seen, so this is not false ice as far as I can tell.
 
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on December 31, 2013, 01:50:50 PM
Two animations of the Nares Strait. The first one at the beginning of 2013 shows the blocking arch in the Smith Sound firmly in place. The second is the current situation: no arch established and ice transport continues.

 
Title: Re: Home brew AMSR2 extent & area calculation
Post by: jdallen on December 31, 2013, 07:03:47 PM
Wipneus - nicely done!  This strikes me as a major state change in the system.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Neven on December 31, 2013, 10:08:23 PM
jdallen, I don't think it's as big as that, as Nares has remained open all winter in previous years as well (can't remember which ones though).
Title: Re: Home brew AMSR2 extent & area calculation
Post by: TerryM on December 31, 2013, 10:49:04 PM
Believe Nares was last open all year in 2009 (just before the huge 2010 volume drop). Last season PII2012 plugged things up well past the normal dates for opening & we had a positive volume spike.
While Nares Strait doesn't have a large outflow I do think that it's positioning means that when even a small amount of MYI takes this route it weakens the rest of the Lincoln Sea ice allowing far more mobility when melt commences.
If the ice-bridge does not form I'd venture a guess that PIOMAS numbers will come in low for 2014.
Terry



Title: Re: Home brew AMSR2 extent & area calculation
Post by: TerryM on December 31, 2013, 11:16:49 PM
From Dr. Munchow's blog:
http://icyseas.org/2012/06/19/nares-strait-ice-bridge-and-arctic-ice-thickness-change/ (http://icyseas.org/2012/06/19/nares-strait-ice-bridge-and-arctic-ice-thickness-change/)



"I processed and archived maps of [/size]Nares Strait satellite images (http://muenchow.cms.udel.edu/MODIS/)[/font][/color][/size] to guide 2003-2012 analyses of how air, water, and ice change from day to day. Ice arches formed as expected during the 2003/04, 2004/05, and 2005/06 winters lasting for about 180-230 days each year. In 2006/07 no ice arch formed, ice streamed freely southward all year, and this certainly contributed to the 2007 record low ice cover. In 2007/08 the arch was in place for only 65 days. In 2009/10, 2010/11, and now 2011/12 ice cover appear normal as the arches formed in December and lasted until July."[/color][/size][/color]
Title: Re: Home brew AMSR2 extent & area calculation
Post by: ralphw on January 02, 2014, 02:01:23 PM
To clarify your last post

"I processed and archived maps of Nares Strait satellite images to guide 2003-2012 analyses of how air, water, and ice change from day to day. Ice arches formed as expected during the 2003/04, 2004/05, and 2005/06 winters lasting for about 180-230 days each year. In 2006/07 no ice arch formed, ice streamed freely southward all year, and this certainly contributed to the 2007 record low ice cover. In 2007/08 the arch was in place for only 65 days. In 2009/10, 2010/11, and now 2011/12 ice cover appear normal as the arches formed in December and lasted until July."
Title: Re: Home brew AMSR2 extent & area calculation
Post by: TerryM on January 02, 2014, 02:33:23 PM
RalphW


Thanks so much for straightening that out. No idea why my posts sometimes get eaten up that way.
Terry
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on January 03, 2014, 07:31:12 AM
No update for 2014 yet from Uni Hamburg...

Graphs are still maintained, see the top post (https://forum.arctic-sea-ice.net/index.php/topic,382.0.html)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Jim Hunt on January 06, 2014, 07:08:06 PM
No update for 2014 yet from Uni Hamburg...

The updates have started again. 1st and 5th are currently available.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on January 07, 2014, 08:01:20 AM

The updates have started again. 1st and 5th are currently available.

Indeed: days 2, 3, 4 and 6 make the set complet now. Also IARC-IJIS has begun updating (version 2).

So we can have a look at a possible day record low now.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: crandles on January 07, 2014, 11:29:53 AM

So we can have a look at a possible day record low now.

01,06,14126244,13689257,13116894,-9999,13571020,13152013,12887212,12815784,12844393,12852098,12850810,12766882,12606948,12834052,12582524,12545921

is first lowest for quite some time.

Area however is higher than all of last 8 years.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on January 09, 2014, 07:58:19 AM
My calculation joins that of IARC-Jaxa:

2014-2013 diff in: Total.Extent Total.Area

     20140106   0.11961720  0.2401091
     20140107   0.06502912  0.2042370
     20140108  -0.07332161  0.0239202

NSIDC and my calculation from UH SSMIS calculated sea ice concentration still are above 2013.

Hudson, Baffin and st. Lawrence are causing today's dip.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on January 09, 2014, 08:07:00 AM
An irregular update of the Nares Strait animations.

Still no ice arch in the Smith sound. However, at the beginning of Nares, Robeson Channel, an arch has held for a couple of days now.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Andreas T on January 09, 2014, 09:24:02 PM
the IR image on DMI shows this is due to a large floe wedged in the channel
http://ocean.dmi.dk/arctic/images/MODIS/Lincoln/201401031302.NOAA.jpg (http://ocean.dmi.dk/arctic/images/MODIS/Lincoln/201401031302.NOAA.jpg)
http://ocean.dmi.dk/arctic/images/MODIS/Lincoln/201401091336.NOAA.jpg (http://ocean.dmi.dk/arctic/images/MODIS/Lincoln/201401091336.NOAA.jpg)
the floe seen on the 3rd broke into smaller pieces but seems strong enough to hold, with thinner ice forming behind it.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on January 11, 2014, 09:24:32 AM
Thanks Andreas. The "arch" is still in place:

Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on January 11, 2014, 09:46:44 AM
Time for a look at the Fram Strait. The transport has a "hiatus", causing the Greenland Sea Ice Extent to drop (see the regional graphs).
The ice to the north Svalbard seems to be reluctant to come any closer to the islands. This in contrast with the side facing the Barentsz Sea. Looking at the animations I can't help to think thatwinds are not enough explanation and currents are involved the West Spitsbergen Current (http://en.wikipedia.org/wiki/West_Spitsbergen_Current)

(Click on attached image to "animate")
Title: Re: Home brew AMSR2 extent & area calculation
Post by: jdallen on January 11, 2014, 10:26:54 AM
Time for a look at the Fram Strait. The transport has a "hiatus", causing the Greenland Sea Ice Extent to drop (see the regional graphs).
The ice to the north Svalbard seems to be reluctant to come any closer to the islands. This in contrast with the side facing the Barentsz Sea. Looking at the animations I can't help to think thatwinds are not enough explanation and currents....

Concur. If you look at the SSTs, west of Svalbard has consistently been 3-8C above zero. I think there is an upwelling of warmer water. I don't think ice *can* form there...
Title: Re: Home brew AMSR2 extent & area calculation
Post by: werther on January 11, 2014, 12:24:56 PM
Interesting graph, Wipneus...
The remnants of the 'Barentsz Bite' still show (like on ASCAT). There's not enough volume/growth to fill up N of Svalbard....? Occurred several years since 2000....
And the West Spitsbergen Drift continues N of Svalbard, counterclockwise along the continental slope (getting more Atlantic water in all the time).
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Shared Humanity on January 11, 2014, 05:46:37 PM
From that animation, transport through the Fram has slowed down but there looks to be a great deal of melting going on as well. Is this unusual for this time of year?
Title: Re: Home brew AMSR2 extent & area calculation
Post by: johnm33 on January 11, 2014, 08:56:35 PM
My 2c's Looks like the warm water flushing nares may have eroded a channel around to fram, if it continues the ice will thin and slam shut, then it open up nares again.
The new portal from Espen [thanks] has an ice temp link which shows up the warmer ice over by barrow and mackenzie +.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on January 13, 2014, 08:07:14 AM
From that animation, transport through the Fram has slowed down but there looks to be a great deal of melting going on as well. Is this unusual for this time of year?

I think there is both melting and freezing in the Greenland Sea. The fact that slowdown of the Fram transport causes lesser ice cover, probably shows that melting is dominant.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on January 13, 2014, 08:15:04 AM
Neven has a blog post (http://neven1.typepad.com/blog/2014/01/cracks-and-the-mobility-of-ice-in-the-beaufort.html), re-blogged from Chris Reynold's dosbat (http://dosbat.blogspot.com/) about the ice movement in the Beaufort.

Time for an animation. Cracks are vaguely visible, but give an idea of considerable ice movements. These are currently stopped as the anti-cyclone has gone.

(click on image to animate)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on January 18, 2014, 10:58:45 AM
Nares: entrance is still blocked. An arch has formed in the Smith Sound, and held now for a couple of days. It is a bit north of last years arch though, no idea if there are more stable configurations.

 
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Andreas T on January 18, 2014, 10:17:48 PM
Wipneus, I am intrigued by the changes in brightness ( in your post of the 13th ) of the landfast ice between some islands of the canadian archipelago. The same can be seen in the landfast ice on the north coast of Greenland (your animation of the11th). Striking is that  other ice nearby does not show these fluctuations with fairly sharp delineation. What makes this ice different? It probably has been deformed less, a look at the DMI satellite images (Greenland) shows that some of that ice is over two years old but not all, so maybe thickness is not what distiguishes it?
What else could affect its appearance in the imagery. Snow cover?
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on January 19, 2014, 10:28:41 AM
Wipneus, I am intrigued by the changes in brightness ( in your post of the 13th ) of the landfast ice between some islands of the canadian archipelago. The same can be seen in the landfast ice on the north coast of Greenland (your animation of the11th). Striking is that  other ice nearby does not show these fluctuations with fairly sharp delineation. What makes this ice different? It probably has been deformed less, a look at the DMI satellite images (Greenland) shows that some of that ice is over two years old but not all, so maybe thickness is not what distiguishes it?
What else could affect its appearance in the imagery. Snow cover?

Andreas,

At first, in these animations I exaggerate the concentration differences by applying a gamma correction. Sometimes a bit more aggressive, to make the differences and the movements more visible. In other words the differences are there, but not as big as you may think.

Second these ice concentration data are based on calculations that try to minimize the influence of the type of ice and snow cover. The ARTIST Sea Ice (ASI) algorithm is particularly good in this, due to the higher frequency microwave band that it uses (89 GHz). The downside is that water vapor in the atmosphere is a disturbing factor, I often see that high pressure over the ice gives lower concentrations.

Summarized, these animations are good to see ice movement, development of cracks, gaps and ice edges. For the surface conditions we should look at other microwave bands, Those are available but I lack the time at the moment to have a good look at them.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Andreas T on January 19, 2014, 09:06:10 PM
Thank you for that information which helps to 'read' those animations, and once more, I appreciate very much the time and effort you put into letting us see things more clearly.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on February 02, 2014, 09:52:22 AM
Two week animation of Fram Strait sea ice concentration. Two weeks of near zero transport of voluminous ice.

(click on attached image to "animate")
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on February 18, 2014, 07:53:56 AM
Watch how the ice is retreating from Svalbard, Frans Josef Lands and the Barentsz sector.
The Fram Strait transport is slowly taking up again.

(assuming you clicked the attached animation)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: jdallen on February 18, 2014, 08:30:30 AM
Watch how the ice is retreating from Svalbard, Frans Josef Lands and the Barentsz sector.
The Fram Strait transport is slowly taking up again.

(assuming you clicked the attached animation)

Astonishingly, I see melt as well as compaction, if you look at the ice immediately to the east of Svalbard at the start of the animation.  Not a lot, but significant in context, I think.

I notice also that Fram export was still active during the time of the animation, if not that high.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Neven on February 18, 2014, 09:31:28 AM
Wow, spectacular.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: wanderer on February 18, 2014, 10:09:08 AM
Svalbard:
"Last 30 days: Average temperature was -1.2 °C, 14.8 °C above the normal."

Crazy!
http://www.yr.no/place/Norway/Svalbard/Longyearbyen/statistics.html (http://www.yr.no/place/Norway/Svalbard/Longyearbyen/statistics.html)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: LarsBoelen on February 18, 2014, 10:23:53 AM
Wow that is spectacular, is this a flow of "hot" Atlantic water doing this? The path to the pole seams weak already, it'll be interesting to sea what spring is going to bring if this continues.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: werther on February 18, 2014, 10:56:54 AM
Thanks Wipneus,

Reading Neven, Wanderer, Lars... yes, there's nothing even remotely close to the impact of invading warmth in mid Feb since at least '97.
I checked 11-15 Feb anomaly on NCEP/NCAR on that. It seems to be related to the latest SSW flash, the split cold poles on 500Mb and the SLP pattern. There is no extreme cold on 850Mb over the Arctic Basin, allowing the concentrated influx of warmth from the S to get to a mean +8C anomaly over the whole 7.3 Mkm2 Basin.
I'll check Ascat metop again to find out if the 'Barentsz Bite', that has remained visible all winter, is showing signs of weakening. Wipneus' animation does...

Lars, that Atlantic water is at work on a constant basis. I think it allows the Barentsz Sea to perform 'Atlantic' for at least the latest 10 years. It progressively strengthens the ice-free zone N of Svalbard (prolonged near surface flow of the West Spitzbergen current). The present temp anomaly  is an atmospheric phenomenon though.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: werther on February 18, 2014, 11:32:34 AM
Here’s a detail from ASCAT 17 Feb:

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi1036.photobucket.com%2Falbums%2Fa446%2Fhanver1%2FArctic%2520Ice%25202014%2FASCATday17022014_zps5d020c10.jpg&hash=e37652fed076c6c347abfca375d23ee8)

The ice front is now 380 km N of Nordaustlandet/Svalbard, at its farthest. Through compaction it shows up as a white rim. North of that rim is the mark of last summers’ Barentsz Bite, showing less reflective, young ice with older splinter floes. Less reflective probably from lesser snow cover, snow less dry because of the close to zero temps.
The main pack to the Pole is more reflective through thickness/dry snow cover. The weakness on a band through the Pole, dating from last summer, still visible.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Shared Humanity on February 18, 2014, 02:04:34 PM
Svalbard:
"Last 30 days: Average temperature was -1.2 °C, 14.8 °C above the normal."

Crazy!
http://www.yr.no/place/Norway/Svalbard/Longyearbyen/statistics.html (http://www.yr.no/place/Norway/Svalbard/Longyearbyen/statistics.html)

Looking at this chart, it seems there was a similarly anomalous warm period last February as well. While not as warm, it still deviated sharply from historical averages. What did January of 2013 look like?
Title: Re: Home brew AMSR2 extent & area calculation
Post by: werther on February 18, 2014, 02:29:45 PM
Hi SH,

Sure, there were several anomalous temp periods in Longyearbyen winter '12-'13. But those were more local than the one we're seeing this Feb.

For Jan 2013, IIRC there was an enduring warm anomaly up to +8dC in the central Arctic Basin, due to a 'warm high' induced by the main SSW event late Dec-early Jan.
Feb was very cold. That's why there's a good chance that 'winter power' will be less this year.

But lets just wait a little; ECMWF does project a restauration of the 'cold pole' over the CAB after 20 Feb. Although that can hardly be severe, because there's not that much cold (and another bite, diluting what's left, will be heading for the US...).
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Buddy on February 18, 2014, 02:33:29 PM
Here's two charts that show the "average temperature above the 80th parallel" for both 2014 (so far) and 2013 (full year).  The difference between 2014 and 2013 for the first 50 days of the year is DRAMATIC.   Look at the 2nd and 3rd graphics on this link:

https://www.blogger.com/blogger.g?blogID=3668502585335462792#editor/target=post;postID=3138607357704998522;onPublishedMenu=allposts;onClosedMenu=allposts;postNum=12;src=link (https://www.blogger.com/blogger.g?blogID=3668502585335462792#editor/target=post;postID=3138607357704998522;onPublishedMenu=allposts;onClosedMenu=allposts;postNum=12;src=link)



Title: Re: Home brew AMSR2 extent & area calculation
Post by: werther on February 18, 2014, 03:48:48 PM
I can't open that link without signing in, Buddy.

But I have a general idea of what your graphs show.
NCEP/NCAR also presents a major difference for the first six weeks of 2014 compared to last year. Over the whole Arctic Basin (I mean the CAB with its peripheral seas, but without the CAA and Barentsz) the average anomaly was between +1/+2 dC in '13. It is about +5dC now.
This extends well into the Bering Sea, Baffin Bay and the Barentsz Sea too.

The only 'compensation' was the colder than usual autumn refreeze.

Just the S. Laptev and Kara Seas had some decent freezing. But looking on MODIS r05c05, just available by the first spring sunlight, ice quality in the Laptev doesn't look great. You'll see lots of wide cracks, barely refrozen, between the usual polynia N of the Lena delta, Tiksi and Great Lyakhovsky Island.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Buddy on February 18, 2014, 04:04:43 PM
Werther:

Going to be an interesting year for weather.....THAT is for sure (and already HAS BEEN for January and February).  You "scientific ice watcher guys" are going to have your hands full this year (unfortunately).

With the SST and air temps much higher than normal (and forecast to stay that way for the next week)......that isn't going to help.

In my mind I keep "fast forwarding" to about 3 years from now when I believe MOST of the Arctic ice sheet will melt out.  More heat absorption can't be good:(

And now the SST anomaly along the east coast of the US has been ramping up over the past several weeks....and all that warmer than usual water is being pumped UP to Greenland and the Arctic......and over to our friends in Britain (just what they need).

Makes a "bean counter" wish he was "science geek" instead...:)



 

Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on February 21, 2014, 07:42:46 AM
A sharp increase in extent in the last two days. Most of this is in the Barentsz sector. Beyond the pack with near 100% concentration, a field with low (near 60-70% according to Uni Hamburgs calculation) concentration has formed.

The ice north of Svalbard also shows a large area extending to the pole with lower concentration, 75-85%.

Some of the boundaries are quite sharp.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: werther on February 21, 2014, 08:04:26 AM
Remarkable, Wipneus!
Yesterday I thought the SIE gain was concentrated mostly in the Bering Sea. But indeed, the Barentsz Sea is kicking in... +150K in two days!
BTW it fits with the ECMWF prognosis for a 'cold pole' restauration over the Arctic Basin.
A low level high is shutting off influx from the S.
AAMOF, winds are supportive for growth on a lot of fringes. Bering, Baffin and Barentsz... a threefold B dash for a late season maximum!
Title: Re: Home brew AMSR2 extent & area calculation
Post by: jdallen on February 21, 2014, 09:58:13 AM
A sharp increase in extent in the last two days. Most of this is in the Barentsz sector. Beyond the pack with near 100% concentration, a field with low (near 60-70% according to Uni Hamburgs calculation) concentration has formed.

The ice north of Svalbard also shows a large area extending to the pole with lower concentration, 75-85%.

Some of the boundaries are quite sharp.

That is really, really disturbing to look at.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Shared Humanity on February 21, 2014, 04:44:06 PM
Wipneus.......that image seems to suggest both compaction and early melt or, more likely, weak winter freeze on the Atlantic side. The 100% concentration on the Atlantic side of FJ and lower concentration on the CAB side has to be due to compaction. Similarly the thin barrier of 100% concentration that borders the lower concentrations over the pole suggest the same thing.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: jdallen on February 21, 2014, 07:00:04 PM
Wipneus.......that image seems to suggest both compaction and early melt or, more likely, weak winter freeze on the Atlantic side. The 100% concentration on the Atlantic side of FJ and lower concentration on the CAB side has to be due to compaction. Similarly the thin barrier of 100% concentration that borders the lower concentrations over the pole suggest the same thing.

Good analysis (as usual), Shared Humanity.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on February 26, 2014, 09:25:08 AM
Gulf of St. Lawrence is most southern of the 14 regions. The ice cover is probably at or just past maximum winter extent. Most of the ice has concentration well below 100%, a clear ice pack is not to be seen with the "blues" and "reds" scattered all over the place.

Title: Re: Home brew AMSR2 extent & area calculation
Post by: jdallen on February 26, 2014, 09:34:27 PM
Gulf of St. Lawrence is most southern of the 14 regions. The ice cover is probably at or just past maximum winter extent. Most of the ice has concentration well below 100%, a clear ice pack is not to be seen with the "blues" and "reds" scattered all over the place.

The Gulf of St. Lawrence also makes up a big slug of the extent which in total numbers is keeping 2014 from falling to the lowest maximum extent and area on record.  I think drops in area/extent there may explain the retreat we've seen in numbers over the last few days.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on February 27, 2014, 09:31:54 AM
Yes, but also the Baffin, Barents, Bering and Okhotsk regions are very volatile at the moment. Today it is the Sea of Okhotsk with the largest delta, far larger than the net change (1000 km2):

Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   -5.6                     0.0                     0.4
               Kara Sea             Barents Sea           Greenland Sea
                   -4.8                   -14.0                     4.3
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                  -10.4                    -2.1                     0.1
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                    0.2                    -0.1                     2.7
             Bering Sea          Sea of Okhotsk            Total Extent
                   -8.6                    40.6                     2.7



Title: Re: Home brew AMSR2 extent & area calculation
Post by: jdallen on February 27, 2014, 11:25:42 PM
Yes, but also the Baffin, Barents, Bering and Okhotsk regions are very volatile at the moment. Today it is the Sea of Okhotsk with the largest delta, far larger than the net change (1000 km2):

You are as usual, faultlessly accurate.  The key take away for the entire season seems to revolve around the word "Volatile".
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on March 02, 2014, 10:22:24 AM
Two animations for the Laptev Sea, to compare 2013 with 2014. Movements of the ice are bigger in 2014, and the lower (darker) concentration is noticeable.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on March 08, 2014, 10:28:46 AM
Today's  dip is mostly by the ice in the Sea of Okhotsk, with a bit of help from far away Barents Sea.

The Okhotsk region is very volatile at the moment, in a few days all those reds could be ice again.

 
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on March 09, 2014, 08:17:10 AM
Total drop in extent today (20140308) : -158k8.

Of that the Sea of Okhotsk takes the lions share, -112k7. A century break for a region is remarkable, even in the middle of summer, but in March?

The Barents Sea corner is also "under a torch", so to speak. Attached is the difference map.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: werther on March 09, 2014, 09:29:29 AM
Thanks for the visualization, Wipneus.
As predicted by ECMWF, strong Southern influx on the Barentsz side. Now starting to be visible on MODIS too. The ice stacks up on the S side of the Frantsa Yosefa Islands, Ushakov etc. In the wake on the N side open sea is emerging (with little indication of new ice formation, it was just a few dC below zero there last week).
Yesterday had a strong storm in the Okhotsk.
There's a lot to say for the extent max being 6 March, although winds change.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Rubikscube on March 09, 2014, 01:42:44 PM
There's a lot to say for the extent max being 6 March, although winds change.

Agreed. It seems like there is a pattern change going on as the constant southerly flow that have been feeding the atlantic arctic with warm air is going to be cut of for some time, and cold will also be digging in over Bering. A late spring rebound should not be ruled out. Though, I'm getting increasingly worried about what will happen to the russian snow pack this spring if the warmth starts flowing in to Russia instead of the Arctic.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: werther on March 09, 2014, 11:39:27 PM
Rubikscube, yes, ECMWF sure shows a changing pattern. But it also shows there's just not enough cold over the Arctic to really have a lasting impact.
Meanwhile, MODIS reveals more and more, FI this 'slaughterhouse' N of Frantsa Yosefa:

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi1036.photobucket.com%2Falbums%2Fa446%2Fhanver1%2FArctic%2520Ice%25202014%2FLMr03c04day6809032014_zpse1b5b93e.jpg&hash=f99afb5816eebda2aeca7916fe0e8810)

The 'wake' is about 100 km deep, to the S a 100 km of piled left-overs from the Barentsz Sea.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: jdallen on March 10, 2014, 07:33:31 AM
Rubikscube, yes, ECMWF sure shows a changing pattern. But it also shows there's just not enough cold over the Arctic to really have a lasting impact.

Very much so.  I think even more crucial is,  "Sunrise" is well above 80N now. So I believe the rapidly increasing energy budget of the region will be unfavorable for shedding heat fast enough to permit anything beyond surface freezing. 

Meanwhile, MODIS reveals more and more, FI this 'slaughterhouse' N of Frantsa Yosefa:
...
The 'wake' is about 100 km deep, to the S a 100 km of piled left-overs from the Barentsz Sea.

It may be very small compared to the energy which will start being delivered after the equinox, but those regions of open water are now *already* picking heat from sunlight which otherwise should have been reflected back out. 

It will be significant in as much as this isn't just "leads" being opened up on a small scale, but rather thousands of KM2 of ocean being directly exposed as light is increasing, rather than decreasing.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Andreas T on March 10, 2014, 08:01:13 PM
don't forget that at shallow angles water reflects.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: icefest on March 10, 2014, 09:26:54 PM
Does water or ice reflect more light/heat at shallow angles?

If the water has a significant amount of chop/waves, would it reflect less?
Title: Re: Home brew AMSR2 extent & area calculation
Post by: jdallen on March 10, 2014, 10:42:34 PM
Does water or ice reflect more light/heat at shallow angles?

If the water has a significant amount of chop/waves, would it reflect less?

Ice has higher albedo, and so would reflect more.  Even at shallow angles, absorption of sunlight would provide notably more energy than it would striking ice.  There is a question of whether ice would prevent more heat loss, but in the end, even freezing, the ice produced at this stage will be quite thin, most likely well under a meter  in thickness.  There just isn't enough time for the heat to be lost.

Title: Re: Home brew AMSR2 extent & area calculation
Post by: Phil. on March 10, 2014, 11:07:56 PM
don't forget that at shallow angles water reflects.

Only one polarization. 
This is the result for air/water:
http://tinyurl.com/mykxfr7 (http://tinyurl.com/mykxfr7)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Andreas T on March 11, 2014, 11:40:50 PM
http://weather1.pme.gov.sa/applied-studies/majala9.pdf (http://weather1.pme.gov.sa/applied-studies/majala9.pdf)
has measurements showing high reflectivity (>0.9) at low sun angles. Waves reduce this strongly. I don't claim that open water is no different from ice but it seems that early in the year the difference can be significantly less than what it is later.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: icefest on March 12, 2014, 02:11:33 AM
I found something:

"When the surface of water is disturbed by wave action, reflection increases by about 20% at low angles of incident light (ca. 5°) to approximately a 10%  increase at higher angles (5-15°). The difference is small at angles of incidence greater than 15° from the horizontal."

If I understand this correctly that means that the current 'holes' are less of a worry for early heat absorption.

From here: http://books.google.com.au/books?id=y9dvhm_pB58C&pg=PA53&lpg=PA53&dq=%22when+the+surface+of+water+is+disturbed+by+wave+action%22&source=bl&ots=5Jfbz0fkNK&sig=_RIPkJW7LMKjkWpqLcvbxqMt28w&hl=en&sa=X&ei=QbMfU6awIsOKlQXJuIGICQ&ved=0CCkQ6AEwAA#v=onepage&q=%22when%20the%20surface%20of%20water%20is%20disturbed%20by%20wave%20action%22&f=false (http://books.google.com.au/books?id=y9dvhm_pB58C&pg=PA53&lpg=PA53&dq=%22when+the+surface+of+water+is+disturbed+by+wave+action%22&source=bl&ots=5Jfbz0fkNK&sig=_RIPkJW7LMKjkWpqLcvbxqMt28w&hl=en&sa=X&ei=QbMfU6awIsOKlQXJuIGICQ&ved=0CCkQ6AEwAA#v=onepage&q=%22when%20the%20surface%20of%20water%20is%20disturbed%20by%20wave%20action%22&f=false)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: werther on March 12, 2014, 08:48:26 AM
Hi Icefest,

For me, the early absorption of the sun's energy in these open waters isn't the worrying part ( we discussed that before on the blog, it starts to be a major contributor in May).
It's the indication that the West Spitsbergen current, aided by the right winds, is now capable of keeping a part, about 100K, of the CAB perennially icefree.

DMI reports a stunning amount of red, positive anomalies, around and N of Svalbard. On its mean SST graph +1dC surface water is indicated,
That's at 81dN, right where the Atlantic Water is entering/starting the Arctic Boundary Current.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on March 12, 2014, 08:52:08 AM
When the "torch" (https://forum.arctic-sea-ice.net/index.php/topic,382.msg21526.html#msg21526) changes to a "freeze ray"
Title: Re: Home brew AMSR2 extent & area calculation
Post by: werther on March 12, 2014, 08:55:49 AM
Yes Wipneus,
That's the Northeaster coming in yesterday.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Andreas T on March 12, 2014, 09:02:14 AM
Icefest, in the quoted paragraph, angles are measured from horizontalvertical (sorry), so waves at the moment reduce reflection. You can relate this to observations most people will have made when being on a boat. A low sun glistens on the sea surface, a high sun doesn't even if you look down at the sea surface at the angle where you would expect reflection. Of course the big difference between ice and water which makes comparison difficult without measurement from all angles (hemispherical reflection) is that the water surface (and a smooth,clear ice surface) reflects strongly in one direction, nothing elsewhere, whereas a snowsurface reflects (scatters) strongly in all directions, some more so than others.
How significant this is, is not easy to quantify, waves clearly play a role, I just brought this up because I don't expect much warming from a sun which has low intensity in W/m2 because of its low incidence and is reflected at maybe 50%.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Chuck Yokota on March 12, 2014, 02:28:17 PM
I don't know how significant it is, but Rayleigh scattering can scatter up to 1/4 of the solar flux (making the sky blue).  This diffuse sky radiation would, I would think, have an advantage over low angle direct sunlight in penetrating the ocean surface.  Does anyone have any data on this?
Title: Re: Home brew AMSR2 extent & area calculation
Post by: crandles on March 12, 2014, 02:43:26 PM
I don't know how significant it is, but Rayleigh scattering can scatter up to 1/4 of the solar flux (making the sky blue).  This diffuse sky radiation would, I would think, have an advantage over low angle direct sunlight in penetrating the ocean surface.  Does anyone have any data on this?

Can provide this diagram:

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fupload.wikimedia.org%2Fwikipedia%2Fcommons%2F7%2F7c%2FAtmospheric_Transmission.png&hash=4364e32455d3bf4f3b3431d3898d507f)

which probably doesn't help that much.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Phil. on March 12, 2014, 03:58:59 PM
I don't know how significant it is, but Rayleigh scattering can scatter up to 1/4 of the solar flux (making the sky blue).  This diffuse sky radiation would, I would think, have an advantage over low angle direct sunlight in penetrating the ocean surface.  Does anyone have any data on this?

Yes diffuse light will increase absorption, hence some light clouds, mist will significantly increase scattering over bigger angles and have an even bigger effect.  Between 25% (blue) and 5% (red) of direct light is Rayleigh scattered.  The scattering isn't uniform in angle the scattered intensity at right angles is about half the maximum value near direct forward and back scattering.  As I pointed out earlier polarization has an effect, this is why sunglasses cut the glare, at about 30º to the horizon all of the p-polarized light is absorbed, the 'glare' is all s-polarized.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Andreas T on March 12, 2014, 10:42:57 PM
Chuck, http://weather1.pme.gov.sa/applied-studies/majala9.pdf (http://weather1.pme.gov.sa/applied-studies/majala9.pdf) covers this, showing albedo of the water surface for different sunangles and different atmospheric transmittance, i.e. more or less diffuse light.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: epiphyte on March 13, 2014, 04:05:48 AM
@crandles... probably this should qualify as a "silly question" - if so, apologies - but going by the diagram you posted above, most of the atmospheric absorption of reflected energy is due to co2 ( in the near IR) and water vapor ( in the far IR). Is it the case that the 100% long-wavelength absorption shown in the diagram is independent of temperature/humidity, or does some proportion of this energy escape back into space when the air is too cold to harbor much water vapor?

The reason I ask is that I'm wondering if arctic far-IR absorption increasing with air temperature (especially close to 0 degrees C) ,  is a positive-feedback mechanism that comes into play with the presence of early melt-season open water?
Title: Re: Home brew AMSR2 extent & area calculation
Post by: crandles on March 13, 2014, 02:41:53 PM
@crandles... probably this should qualify as a "silly question" - if so, apologies - but going by the diagram you posted above, most of the atmospheric absorption of reflected energy is due to co2 ( in the near IR) and water vapor ( in the far IR). Is it the case that the 100% long-wavelength absorption shown in the diagram is independent of temperature/humidity, or does some proportion of this energy escape back into space when the air is too cold to harbor much water vapor?

The reason I ask is that I'm wondering if arctic far-IR absorption increasing with air temperature (especially close to 0 degrees C) ,  is a positive-feedback mechanism that comes into play with the presence of early melt-season open water?

I think reflected energy is the same wavelength as incoming. So I assume 'reflected' in the first sentence quoted is just a mistake and you are really talking of Earth radiating heat in infra-red.

 I am not certain of the meaning of the pink, black and blue curves but assume these are something like radiation from earth at temperatures appropriate to equator, 45 degrees N or S and pole (maybe tropics, mid latitudes and Arctic/Antarctic circles).

Water vapour absorbs at near and far infra-red wavelengths. The window between these is partly covered by CO2 absorption. The window will be slightly larger for the poles because the atmosphere can hold less water vapour at polar temperature causing less widening of absorption bands with concentration of water vapour. There is also more outgoing radiation at the wavelengths covered by CO2 absorption in the window because Earth is colder at the poles as shown by black versus pink curve.

I am a bit unsure of even the above let alone speculating further.

I assume that virtually all radiation from earth escaping to space will be in or near the window. Is it fully 100% absorbed at longer wavelengths? From surface I would expect it is as near as makes no difference fully 100% absorbed. However, I would think that there must mbe some height from which some small part escapes - this will then be atmosphere emitting to space rather than re-absorption by atmospheredirect from earth. The distribution between wavelengths will then depend on atmosphere temperature rather than surface temperature so where atmosphere is warmer with temperature inversion there may be less radiation at those longer wavelengths. I expect this would only be a small effect near the top of the atmosphere for radiation emission.

There are bound to be others far more expert on this than me.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Andreas T on March 13, 2014, 06:45:23 PM
Crandles is right to be cautious about speculating what changed temperatures in the arctic would do to outgoing radiation. Ray Pierrehumbert always points out that what matters for earth's heat budget is top of atmosphere radiation. For different wavelengths that will come from various depths in the atmosphere, even the surface in the windows if the sky is clear. The AVHRR images on the DMI Greenland I have been watching for the first time this winter show increased infrared into space for low clouds. Of course that is only part of the spectrum, but clearly a snow covered surface will drop to a very low temperature and radiate less according to that temperature, the same surface will stay warmer under a cloudy sky, but the clouds, which result from warmer more humid air also radiate outwards and if warmer than the cloudless surface radiate more. The curves shown in the graph (for 210 to 310K) are clearly standardized to a fixed height, absolute intensity is lower for lower temperature. These clouds of course would cool through this and precipitate unless they are maintained by some advection I guess. That is why people build models for this stuff, trying to factor in all these complexities.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: epiphyte on March 14, 2014, 06:10:02 AM
Wow. I'm tempted to just say "Right then, it's complicated. Get that." and retire into the shadows after all that... but just can't resist wondering if the increased radiation to space under cloudy conditions is due to incoming light which was absorbed by those same clouds, and then partially re-radiated as IR, or from IR which was radiated from the ground, absorbed by the clouds, and then re-radiated to space.

In either case the cloudless, low-humidity alternative (at least when it is cold and ice is present) would seem to be that much of the energy coming in gets reflected, or alternatively absorbed and then radiated, directly,  from the high-albedo ice?

Complexities aside - is there a possible rule-of-thumb here... I.e. "The simpler the path that incoming solar energy has back to space, the less will be retained by the overall system"?
Title: Re: Home brew AMSR2 extent & area calculation
Post by: crandles on March 14, 2014, 12:41:29 PM
Complexities aside - is there a possible rule-of-thumb here... I.e. "The simpler the path that incoming solar energy has back to space, the less will be retained by the overall system"?

I have wondered if it is reasonably correct to say that

The more complex the path that outgoing radiation takes to get to space, the longer the heat is retained in the system and the higher the surface temperature. So if on average heat is radiated and absorbed say 32 times before it reaches the effective radiating height to be emitted to space while in a pre-industrial climate it only took on average 30 radiations to reach the effective radiating height this might give a sense of how much effect we are having on the atmosphere.

However, experts seem to stress the increase in the effective radiating height.

I don't quite follow why that is stressed rather than average number of times heat is radiated. It seems to me that effective radiating height understates the effect if average radiation distance / height gain is declining due to a more opaque atmosphere. Perhaps it is complicated by the average height gained by heat via convection rather than by radiation.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Chuck Yokota on March 14, 2014, 03:32:11 PM
It is not the length of time it takes the infrared energy to get to the top of the atmosphere and escape, but the fact that the energy is absorbed and then re-emitted non-directionally, as likely downward as upward.  This means that in order to get enough energy up to the top of the atmosphere, the surface and lower part of the atmosphere have to heat up (using the downward-emitted energy) to produce enough infrared energy that the part of it that is emitted from the top of the atmosphere balances the incoming solar energy.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on March 19, 2014, 07:21:06 AM
Time for an update of the Fram/Barents section. Transport through the Fram is quite active.
The broken sea ice around Svalbard and Frans Jozef land is very movable and some spectacular cracks are appearing in what looked like the consolidated ice pack.

(click the image for an animation)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: epiphyte on March 19, 2014, 08:06:52 AM
So this is what a record March increase in extent looks like...

In the words of Bilbo Baggins :
... Sort of thin - Stretched - like butter scraped over too much bread.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: sofouuk on March 19, 2014, 02:54:31 PM
lol
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Shared Humanity on March 19, 2014, 03:52:15 PM
Time for an update of the Fram/Barents section. Transport through the Fram is quite active.
The broken sea ice around Svalbard and Frans Jozef land is very movable and some spectacular cracks are appearing in what looked like the consolidated ice pack.

(click the image for an animation)

It sure looks like the transport of ice is not simply through the Fram. The ice also appears to be moving rapidly towards the Atlantic both south and north of Frans Jozef.

Given the fragile state of the Atlantic side of the CAB, if a persistent high were to set up over a cold Greenland, could we see this kind of ice transport through the summer? With the current water temperature anomalies in the Barents and Greenland Seas, this ice would meet a quick demise.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: jdallen on March 19, 2014, 05:53:29 PM
Time for an update of the Fram/Barents section. Transport through the Fram is quite active.
The broken sea ice around Svalbard and Frans Jozef land is very movable and some spectacular cracks are appearing in what looked like the consolidated ice pack.

(click the image for an animation)

It sure looks like the transport of ice is not simply through the Fram. The ice also appears to be moving rapidly towards the Atlantic both south and north of Frans Jozef.

Given the fragile state of the Atlantic side of the CAB, if a persistent high were to set up over a cold Greenland, could we see this kind of ice transport through the summer? With the current water temperature anomalies in the Barents and Greenland Seas, this ice would meet a quick demise.

I concur with SH. This could be a very significant change in behavior, and a direct consequence of the increased fracturing of the pack.  Combine the movement with the massive increases in heat content of the Barents, and we now have a new ice grinder.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on March 22, 2014, 08:45:43 AM
Animation of Laptev/Kara. Mobility of the ice is great, even the "stubborn" ice in Kara in 2013 showing big cracks now.

(click image for animation)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: jdallen on March 23, 2014, 05:44:38 AM
That looks bad. Note the lowconcentration as well.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on March 24, 2014, 08:05:17 AM
Melting season start with a fat century drop in extent ( -112k for the "home brew extent" ).

The decline is in the lowest latitude regions (Okhotsk and St Lawrence), other regions: not much change.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on March 27, 2014, 07:43:08 AM
Small overall increase today (+6k), with the St.Lawrence the leader (+26k).

Title: Re: Home brew AMSR2 extent & area calculation
Post by: Yuha on March 27, 2014, 07:53:03 PM
Small overall increase today (+6k), with the St.Lawrence the leader (+26k).

Some of the reported new ice in St. Lawrence appears to be true but some of it is clearly false.
There was a thick cloud cover in the area on the 26th.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on March 31, 2014, 08:10:22 AM
Time for a look at the Fram Strait. Transport of sea ice looks strong. The source of the sea ice is not just from the central Arctic, but also from the north of Greenland now. This would imply an increase in export of thick multi-year ice.

Ice has not been so near north Svalbard for a while.  The ice in the Barents Sea is extending still, the cover is probably thin ( I will have a look at SMOS soon) and could vanish as quickly as it came.

(click image for an animation)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Shared Humanity on March 31, 2014, 05:35:02 PM
I have only been visiting here for a couple of years but does that ice along the northeast coast of Greenland look more fragile than usual?
Title: Re: Home brew AMSR2 extent & area calculation
Post by: jdallen on March 31, 2014, 05:37:32 PM
I have only been visiting here for a couple of years but does that ice along the northeast coast of Greenland look more fragile than usual?
It has become more fragile. There is considerably less land fast ice than two years ago.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on April 11, 2014, 01:24:46 PM
The last two weeks in the Laptev and Kara sectors. Maybe not that unusual, but the ice is very mobile: sloshing to an fro. Further to the North Pole, the ice seems to have decided not to wait and is taking the Transpolar Drift Express.

(click that picture, I hope it animates)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Jim Hunt on April 11, 2014, 01:33:07 PM
Maybe not that unusual, but the ice is very mobile: sloshing to an fro.

See also the current DMI ice temperature map:

http://GreatWhiteCon.info/resources/arctic-sea-ice-graphs/#DmiTemp (http://GreatWhiteCon.info/resources/arctic-sea-ice-graphs/#DmiTemp)

I hope that page is OK with you Wipneus? Please let me know ASAP if you spot any obvious errors or omissions!
Title: Re: Home brew AMSR2 extent & area calculation
Post by: lanevn on April 11, 2014, 03:46:50 PM
Can you say where to get AMSR2 map for any day. I can find only for last day, and the day before last.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Jim Hunt on April 11, 2014, 04:23:05 PM
Can you say where to get AMSR2 map for any day.

The University of Hamburg flavour are all available via FTP from: ftp://ftp-projects.zmaw.de/seaice/AMSR2/
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on April 11, 2014, 04:23:59 PM
You can find the images created by the people of the University of Hamburg here:

ftp://ftp-projects.zmaw.de/seaice/AMSR2/3.125km/ (ftp://ftp-projects.zmaw.de/seaice/AMSR2/3.125km/)

some people like the images that I create (from the NETCDF data files from Uni Hamburg). These (last 5 months or so) are here:

https://sites.google.com/site/apamsr2/home/pngcby32 (https://sites.google.com/site/apamsr2/home/pngcby32)

(reason could be that my files are a lot smaller)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: lanevn on April 11, 2014, 11:50:19 PM
Thanks
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on April 12, 2014, 09:23:04 AM
A big crack develops through the East Siberian Sea, a (first) sign that the ice may not be that solid here as it appeared to be.

(must click for an animation)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: BornFromTheVoid on April 12, 2014, 10:35:25 AM
Nice work Wipneus. I suspect that crack is in response to the storm that moved over the New Siberian Islands over the last 36 hours.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: werther on April 12, 2014, 10:40:55 AM
Morning all!
Thanks Wipneus. Yes BFTV, it was driven open from Pevek Bay to Kotelnyi Island in about two days, today up to 40 km wide, total surface around 25K. Doesn't refreeze much up to this moment. Must have an influence on CT SIA soon.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on April 15, 2014, 07:49:46 AM
Time for an updated animation of the Greenland Sea sector. The ice in the Fram Strait continues to move south.
The icepack in the Central Basin seems to make a 90 degrees turn: cracks that run more or less east-west in the beginning are south-north oriented in the last two frames/

(click the picture for that animation)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: werther on April 15, 2014, 01:18:13 PM
Thanks again, Wipneus!
Must have an influence on CT SIA soon.
Funny, it does.... CT SIA has gone down about 400K in four days. Impressive performance, that Low!
Title: Re: Home brew AMSR2 extent & area calculation
Post by: werther on April 15, 2014, 08:58:40 PM
A detail 100x130 km in the East Siberian Sea, 15 April:

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi1036.photobucket.com%2Falbums%2Fa446%2Fhanver1%2FArctic%2520Ice%25202014%2FDetailEastSibSea15052014small_zps526ef0e0.jpg&hash=98bab71b14435022a957604e19aa1741)

This enhances what a potent Low can do to the ice in mid April.

The initial stress lead (drawn in red lines) that opened the 11th has lost its shape. The tearing force of wind and tide cracked the adjacent ice. That goes for the pack ice on the left, which is splintering up like it did summer 12 and 13. The fast ice gives in too, breaking in 60 km wide swaths.

This is straight in ‘old’ ice that made it through last summer. The thin arm has been recognizable on ASCAT all winter. It doesn’t look to have gained much strength, nor thickness.
It makes me wonder, what role did this winters’ snowpack play on the ice? The members of Expedition Hope mentioned the snow cover, too (even though they’re 2100 km further on the ice).

Winter power wasn’t great. PIOMAS confirmed on volume. Where‘s this going this season?
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on April 18, 2014, 08:56:26 AM
A spectacular decrease today:

Update 20140417.

Extent: -171.3 (-297k vs 2013)
Area: -285.8 (-428k vs 2013)

The usual regions are Okhotsk, Bering and St.Lawrence. Today they get help from Baffin, Greenland Sea and Barents. Especially the ice in the Barents Sea and near New Foundland looks ready for a quick disappearance.

The details (in 1000 km2):


Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                    4.1                     0.7                    -0.5
               Kara Sea             Barents Sea           Greenland Sea
                    0.2                   -25.0                   -16.8
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                  -54.5                   -12.3                   -25.4
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   -0.5                     0.1                    -2.0
             Bering Sea          Sea of Okhotsk            Total Extent
                  -13.3                   -26.2                  -171.3

Area:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   -3.0                    -8.5                   -12.0
               Kara Sea             Barents Sea           Greenland Sea
                   -4.3                   -30.8                   -22.5
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                 -113.4                   -13.9                   -33.0
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                    1.0                     0.5                    -5.3
             Bering Sea          Sea of Okhotsk              Total Area
                  -12.9                   -27.8                  -285.8


Title: Re: Home brew AMSR2 extent & area calculation
Post by: jdallen on April 18, 2014, 10:00:05 AM
That's stunning, Wipneus, even if most of the activity is peripheral.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on April 19, 2014, 08:15:02 AM
Another day in the Arctic, another day with un-seasonal massive sea ice losses:

Update 20140418.

Extent: -167.6 (-424k vs 2013)
Area: -213.5 (-613k vs 2013)

As observed yesterday the decrease is strong in Barents and Baffin regions.

Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   -2.6                    -1.0                    -8.4
               Kara Sea             Barents Sea           Greenland Sea
                  -11.0                   -63.5                    -1.5
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                  -45.2                    -0.7                    -9.0
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                    0.7                     0.7                    -2.0
             Bering Sea          Sea of Okhotsk            Total Extent
                   -2.7                   -21.6                  -167.6

Area:
           Arctic Basin       East Siberian Sea              Laptev Sea
                  -30.8                    -1.5                   -18.2
               Kara Sea             Barents Sea           Greenland Sea
                  -17.2                   -86.5                    10.1
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                  -45.9                     0.6                    -8.6
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                    8.7                     1.4                    -0.6
             Bering Sea          Sea of Okhotsk              Total Area
                   -4.6                   -20.5                  -213.5

Title: Re: Home brew AMSR2 extent & area calculation
Post by: jdallen on April 19, 2014, 08:57:03 AM
Another day in the Arctic, another day with un-seasonal massive sea ice losses:

Update 20140418.

Extent: -167.6 (-424k vs 2013)
Area: -213.5 (-613k vs 2013)


Looks like my "toboggan" has definitely dropped off the edge of the cliff...

Title: Re: Home brew AMSR2 extent & area calculation
Post by: Shared Humanity on April 19, 2014, 02:51:22 PM
Given the dramatic drops are occurring in peripheral areas, is it possible we could see significant reductions in these drops over the next several weeks as these peripheral lose their ability to drive such rapid ice loss?
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on April 19, 2014, 04:20:40 PM
Given the dramatic drops are occurring in peripheral areas, is it possible we could see significant reductions in these drops over the next several weeks as these peripheral lose their ability to drive such rapid ice loss?

That is what I think too. If you look at the spaghetti of the Jaxa/IJIS graph you see that all lines come close together in the mid of May. The extent at that time signifies little, 2012 is medium and 2004 is one of the lowest, yet in September 2004 has one of the highest ice covers of the bunch and 2012 ...

So unless 2014 is seriously outside of that bottle neck in May, that is probably the time when the real differences only start to become clear.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fwww.ijis.iarc.uaf.edu%2Fseaice%2Fextent%2FSea_Ice_Extent_v2_prev.png&hash=404a0f810ba3a2323c0da8b37e70e5c4)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: crandles on April 19, 2014, 04:29:29 PM
Given the dramatic drops are occurring in peripheral areas, is it possible we could see significant reductions in these drops over the next several weeks as these peripheral lose their ability to drive such rapid ice loss?

It is possible of course but my impression is of large movement of ice into Barents meaning that some places must be being left thin which will start to melt out earlier than usual. Despite the large movement the ice in Barents look sparse and thin suggesting water has been warm enought to melt a lot of ice.

Similarly not much ice in Bering and Chukchi looks well broken up.

Without modis images for last year perhaps my memory is not good enough?

Yes the mid May lines are usually closer together and maybe that will happen again.

-285k then -212k. Wow! Sounds like CT could get near low edge of 2007 for the time of year.
(IJIS only needs to lose 48k in 3 days (though 2004 was lower than 2007).)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on April 19, 2014, 04:34:08 PM

-285k then -212k. Wow! Sounds like CT could get near low edge of 2007 for the time of year.
(IJIS only needs to lose 48k in 3 days (though 2004 was lower than 2007).)

My estimates for CT changes in the coming days (reported on Sat,Sun,Mon):

-49.7 -211.1 -191.4
Title: Re: Home brew AMSR2 extent & area calculation
Post by: crandles on April 19, 2014, 05:06:13 PM

-285k then -212k. Wow! Sounds like CT could get near low edge of 2007 for the time of year.
(IJIS only needs to lose 48k in 3 days (though 2004 was lower than 2007).)

My estimates for CT changes in the coming days (reported on Sat,Sun,Mon):

-49.7 -211.1 -191.4

 12.603 -49.7-211.1-191.4 = 12.151

CT day 109 in 2007 = 12.133
just 18k above 2007 seems to agree with my earlier "could get near" :)

(it is a lot nearer than the current day 106 values of 12.603 vs 2007's 12.267 a 336k difference)

Thanks for the numbers Wipneus.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on April 20, 2014, 09:13:21 AM
The decline continues with a somewhat more believable but still big stride:

Extent: -90.5 (-502k vs 2013)
Area: -142.7 (-773k vs 2013)

The Barents region is still on the decline and is accompanied today by Kara.
As can be seen on the attached animation (you must click for that) the remaining sea ice in the Barents Sea is "not much soup" (Dutch expression, you get the meaning), it may be gone soon depending on the mercy of the weather. The Fram is exporting ice that looks like it is sourced from north of Greenland: probably multi year ice.
 
Title: Re: Home brew AMSR2 extent & area calculation
Post by: jdallen on April 20, 2014, 09:18:35 AM
Judging from models, pretty much everything going out the Fram is MYI right now.  Not much new ice left on this side of the basin to export.

Anecdotally, I'd put the export at about 10K KM2/day.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: ghoti on April 20, 2014, 06:34:14 PM
The newly placed 2014D buoy is heading for the Fram at a good clip so far. We'll see how long it takes to get there.

http://imb.crrel.usace.army.mil/2014D.htm (http://imb.crrel.usace.army.mil/2014D.htm)

Title: Re: Home brew AMSR2 extent & area calculation
Post by: Jim Hunt on April 20, 2014, 08:32:35 PM
The newly placed 2014D buoy is heading for the Fram at a good clip so far. We'll see how long it takes to get there.

I'm not stalking you ghoti, I promise! See also http://GreatWhiteCon.info/resources/ice-mass-balance-buoys/winter-201314-imbs/#2014D (http://GreatWhiteCon.info/resources/ice-mass-balance-buoys/winter-201314-imbs/#2014D) which reveals:
Title: Re: Home brew AMSR2 extent & area calculation
Post by: ghoti on April 21, 2014, 01:45:38 AM
I actually posted that to prod you into showing your buoy tracking!  :D
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on April 22, 2014, 08:21:44 AM
Bad ice in the Barents Sea, and the ice up to the pole does not look much healthier.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on April 23, 2014, 08:06:44 AM
Extent and area are bouncing a bit back from the cliff drop in the past days. Exceptions are the ESS and Laptev Sea. This is why:

(click and the pic will animate)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: icefest on April 23, 2014, 08:19:33 AM
That fast ice isn't looking to flash either.

Is the higher absorption due to water pooling on top, or due to decreased thickness leading to increased translucency?
Title: Re: Home brew AMSR2 extent & area calculation
Post by: werther on April 23, 2014, 08:33:28 AM
Morning Icefest,
I've been looking at the Laptev fast ice a lot spring '12, '13 and now. Ever since I noticed a 'scintillation' on the ice which could possibly be a sign of methane releases and their mark on the ice. This year no sign of these marks can be seen.
It could be a sign of a thicker than usual snow cover. In that case, the greys on Wipneus' graph might indicate the snow pack getting wetter. The same for the yellows on the UniBremen map.

This fits with temperature records, showing +2 and +4 dC in Tiksi for 20-21 April.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: icefest on April 23, 2014, 12:41:19 PM
Thank you Werther.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on April 26, 2014, 09:44:59 AM
Ice is on the move everywhere.

(click the pic to animate)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: jdallen on April 26, 2014, 10:23:01 AM
Ice is on the move everywhere.

Wow... Isn't it unusual for the Amundsen Gulf to break up like that this early? Doesn't an ice bridge normally form at the exit to the Beaufort?  Seems like conditions have blown right past that stage.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: jdallen on April 26, 2014, 07:29:56 PM
Unusual but not extraordinary. Pity so much of lance Modis is missing.

Same dates, approximately.
2009 - solid
http://lance-modis.eosdis.nasa.gov/imagery/subsets/?subset=Arctic_r05c02.2009115.terra (http://lance-modis.eosdis.nasa.gov/imagery/subsets/?subset=Arctic_r05c02.2009115.terra)
2010, not so much...
http://lance-modis.eosdis.nasa.gov/imagery/subsets/?subset=Arctic_r05c02.2010115.terra (http://lance-modis.eosdis.nasa.gov/imagery/subsets/?subset=Arctic_r05c02.2010115.terra)
Today:
http://lance-modis.eosdis.nasa.gov/imagery/subsets/?subset=Arctic_r05c02.2014115.terra (http://lance-modis.eosdis.nasa.gov/imagery/subsets/?subset=Arctic_r05c02.2014115.terra)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: ChasingIce on April 27, 2014, 12:59:09 AM
extraordinary weather has extraordinary results for ice. 
Title: Re: Home brew AMSR2 extent & area calculation
Post by: jdallen on April 27, 2014, 01:48:41 AM
extraordinary weather has extraordinary results for ice.

Indeed.  The Bering has already mostly disintegrated into a slush of nilas and disconnected floes.

http://lance-modis.eosdis.nasa.gov/imagery/subsets/?subset=Arctic_r06c03.2014115.terra.250m (http://lance-modis.eosdis.nasa.gov/imagery/subsets/?subset=Arctic_r06c03.2014115.terra.250m)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Yuha on April 27, 2014, 01:00:48 PM
It seems that the Amundsen Gulf never properly froze up this winter.
See for example these MODIS Terra images from Feb. 19 and Mar. 15.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on May 01, 2014, 08:32:18 AM
Update 20140430.

Net extent decreased a little, with area a larger increase. We are still in early spring where freezing conditions exist in the North (so leads get covered with thin ice) and melting in the peripheral regions.
Today's images show two regions where you may speak of a "torch".


Extent: -7.3 (+52k vs 2013)
Area: +73.9 (+115k vs 2013)

The details (in 1000 km2):

Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   -1.6                     2.2                    -2.0
               Kara Sea             Barents Sea           Greenland Sea
                    0.6                     5.9                    -3.0
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                  -20.0                    -0.8                     2.0
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   -0.7                     6.3                    10.3
             Bering Sea          Sea of Okhotsk            Total Extent
                  -10.8                     4.2                    -7.3

Area:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   15.8                    -2.4                   -18.6
               Kara Sea             Barents Sea           Greenland Sea
                   -1.6                    -0.3                    -0.6
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -0.1                    -0.6                    22.3
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                    2.2                    13.0                    15.5
             Bering Sea          Sea of Okhotsk              Total Area
                   24.0                     5.4                    73.9

Title: Re: Home brew AMSR2 extent & area calculation
Post by: Pmt111500 on May 01, 2014, 09:47:39 AM
Noting that your (Wipneus) graph on PIOMAS volume loss has exposure on http://www.dailykos.com/story/2014/05/01/1296055/-Climate-Change (http://www.dailykos.com/story/2014/05/01/1296055/-Climate-Change)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Frivolousz21 on May 01, 2014, 12:19:16 PM
The Bering is getting smacked.

The Beaufort gets totally back smacked next.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Shared Humanity on May 01, 2014, 04:08:53 PM
Wipneus.....Doesn't that view suggest the Bering is seeing more drift than melt?
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on May 01, 2014, 07:01:21 PM
Wipneus.....Doesn't that view suggest the Bering is seeing more drift than melt?

Indeed, the drift shows southern winds that in this time of year will enhance the seasonal melt.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on May 02, 2014, 08:24:12 AM
Update 20140501.

As Shared Humanity observed yesterday drift is dominating over melt, yet the net figures are negative in the peripheral regions. As images I show the Bering Sea because the pattern is exactly the same as yesterday. Further Barents as an extreme example of lots of ice movements from which you can read the direction of the wind and a small negative total result in extent and area.


Extent: -85.6 (+23k vs 2013)
Area: -52.2 (+148k vs 2013)


The details (in 1000 km2):


Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   -5.3                     0.7                    -4.1
               Kara Sea             Barents Sea           Greenland Sea
                   -1.2                   -10.9                    -2.7
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -8.3                    -0.6                     1.2
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   -2.5                     1.3                    -1.1
             Bering Sea          Sea of Okhotsk            Total Extent
                  -46.0                    -6.3                   -85.6

Area:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   27.2                    22.8                    -9.0
               Kara Sea             Barents Sea           Greenland Sea
                  -13.8                   -14.9                     3.4
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                  -17.6                    -1.6                    10.0
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   -6.8                     7.3                    -2.7
             Bering Sea          Sea of Okhotsk              Total Area
                  -48.9                    -7.6                   -52.2

Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on May 03, 2014, 08:28:26 AM
The march to Fram Strait continues although some ice seems to take a wrong turn and go east of Svalbard.

(click the picture to animate)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: crandles on May 03, 2014, 01:54:43 PM
The march to Fram Strait continues although some ice seems to take a wrong turn and go east of Svalbard.

Yes it is MYI north of Greenland heading for Fram and lots of ice also pushed past Franz Josef. Barents has gained 200k since just before mid March. This will melt out as always but I think the important observation is where is it coming from? I think that Laptev and ESS are being caused to have very thin ice near coasts which will rapidly melt and get albedo feedback going.

Compare Laptev in
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fwww7320.nrlssc.navy.mil%2FhycomARC%2Fnavo%2Farcticict%2Fnowcast%2Fict2014050218_2014050300_039_arcticict.001.gif&hash=5f23ffd8dadb3d3502df64d3c7f61c1f)
vs
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fwww7320.nrlssc.navy.mil%2FhycomARC%2Fnavo%2Farcticict%2Fnowcast%2Fict2013050218_2013050300_035_arcticict.001.gif&hash=4939561c217c6e0ea29a536ff7d5f6ee)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on May 04, 2014, 08:54:12 AM
In this animation of the last two weeks in Kara the ice mobility is obvious. As the winds have constantly blown from the NE quadrant, the ice has been confined in the Kara region. I can only imagine what happens when a warm southerly will blow.

(click on the picture for the animation)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Wipneus on May 06, 2014, 09:19:46 AM
The big crack in the East Siberian Sea is still there, it seems to separate the mobile ice in the Central  Arctic (and other) regions from a big piece of steady (some cracks are visible near the edge though) landfast ice in the ESS and the Laptev Sea.

(must click the picture to start animation)
Title: Re: Home brew AMSR2 extent & area calculation
Post by: werther on May 06, 2014, 09:36:10 AM
Interesting, Wipneus.
The fastice seems to be limited to the 30 m deepness line on the broad continental shelf. Maybe the Arctic Boundary Current has no effective room to get on the shelf further south?
But it does pass south of Wrangel.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: jdallen on May 06, 2014, 09:46:25 AM
Interesting, Wipneus.
The fastice seems to be limited to the 30 m deepness line on the broad continental shelf. Maybe the Arctic Boundary Current has no effective room to get on the shelf further south?
But it does pass south of Wrangel.

I suspect currents are playing more of a role than they have previously.  With the system closer to threshold, those inputs will start having more visible influence.
Title: Re: Home brew AMSR2 extent & area calculation
Post by: Shared Humanity on May 06, 2014, 02:18:09 PM
Interesting, Wipneus.
The fastice seems to be limited to the 30 m deepness line on the broad continental shelf. Maybe the Arctic Boundary Current has no effective room to get on the shelf further south?
But it does pass south of Wrangel.

I suspect currents are playing more of a role than they have previously.  With the system closer to threshold, those inputs will s