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Author Topic: Home brew AMSR2 extent & area calculation  (Read 883776 times)

Wipneus

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Re: Home brew AMSR2 extent & area calculation
« Reply #50 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

Wipneus

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Re: Home brew AMSR2 extent & area calculation
« Reply #51 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.
« Last Edit: July 01, 2013, 09:24:39 AM by Wipneus »

Artful Dodger

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Re: Home brew AMSR2 extent & area calculation
« Reply #52 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)
Cheers!
Lodger

Wipneus

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Re: Home brew AMSR2 extent & area calculation
« Reply #53 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.

Wipneus

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Re: Home brew AMSR2 extent & area calculation
« Reply #54 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

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/

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.

Wipneus

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Re: Home brew AMSR2 extent & area calculation
« Reply #55 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

####

jdallen

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Re: Home brew AMSR2 extent & area calculation
« Reply #56 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.
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Re: Home brew AMSR2 extent & area calculation
« Reply #57 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

Wipneus

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Re: Home brew AMSR2 extent & area calculation
« Reply #58 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)

Wipneus

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Re: Home brew AMSR2 extent & area calculation
« Reply #59 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




wanderer

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Re: Home brew AMSR2 extent & area calculation
« Reply #60 on: July 02, 2013, 10:41:34 AM »
Wow, great work!

When will PIOMAS update?
Can't wait to see the new Volume update!

Artful Dodger

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Re: Home brew AMSR2 extent & area calculation
« Reply #61 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?

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Cheers!
Lodger

Artful Dodger

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Re: Home brew AMSR2 extent & area calculation
« Reply #62 on: July 02, 2013, 11:46:25 AM »
Introducing the regional graphs.

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.
Cheers!
Lodger

Richard Rathbone

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Re: Home brew AMSR2 extent & area calculation
« Reply #63 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?

Pmt111500

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Re: Home brew AMSR2 extent & area calculation
« Reply #64 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.
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Wipneus

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Re: Home brew AMSR2 extent & area calculation
« Reply #65 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?


dbostrom

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Re: Home brew AMSR2 extent & area calculation
« Reply #66 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?

dree12

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Re: Home brew AMSR2 extent & area calculation
« Reply #67 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?

LarsBoelen

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Re: Home brew AMSR2 extent & area calculation
« Reply #68 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!

Wipneus

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Re: Home brew AMSR2 extent & area calculation
« Reply #69 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

Wipneus

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Re: Home brew AMSR2 extent & area calculation
« Reply #70 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

Wipneus

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Re: Home brew AMSR2 extent & area calculation
« Reply #71 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.

Wipneus

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Re: Home brew AMSR2 extent & area calculation
« Reply #72 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.

Bob Wallace

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Re: Home brew AMSR2 extent & area calculation
« Reply #73 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.

Wipneus

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Re: Home brew AMSR2 extent & area calculation
« Reply #74 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

Wipneus

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Re: Home brew AMSR2 extent & area calculation
« Reply #75 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.

dbostrom

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Re: Home brew AMSR2 extent & area calculation
« Reply #76 on: July 03, 2013, 07:57:03 AM »
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.

Wipneus

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Re: Home brew AMSR2 extent & area calculation
« Reply #77 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.

Wipneus

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Re: Home brew AMSR2 extent & area calculation
« Reply #78 on: July 03, 2013, 08:07:53 AM »
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.

Wipneus

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Re: Home brew AMSR2 extent & area calculation
« Reply #79 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


dbostrom

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Re: Home brew AMSR2 extent & area calculation
« Reply #80 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.

Wipneus

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Re: Home brew AMSR2 extent & area calculation
« Reply #81 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)

Neven

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Re: Home brew AMSR2 extent & area calculation
« Reply #82 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?
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Artful Dodger

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Re: Home brew AMSR2 extent & area calculation
« Reply #83 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)
Cheers!
Lodger

Wipneus

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Re: Home brew AMSR2 extent & area calculation
« Reply #84 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.

Frivolousz21

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Re: Home brew AMSR2 extent & area calculation
« Reply #85 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. 
I got a nickname for all my guns
a Desert Eagle that I call Big Pun
a two shot that I call Tupac
and a dirty pistol that love to crew hop
my TEC 9 Imma call T-Pain
my 3-8 snub Imma call Lil Wayne
machine gun named Missy so loud
it go e-e-e-e-ow e-e-e-e-e-e-blaow

Wipneus

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Re: Home brew AMSR2 extent & area calculation
« Reply #86 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


Wipneus

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Re: Home brew AMSR2 extent & area calculation
« Reply #87 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)


Wipneus

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Re: Home brew AMSR2 extent & area calculation
« Reply #88 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.

Peter Ellis

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Re: Home brew AMSR2 extent & area calculation
« Reply #89 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.

Wipneus

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Re: Home brew AMSR2 extent & area calculation
« Reply #90 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.

slow wing

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Re: Home brew AMSR2 extent & area calculation
« Reply #91 on: July 03, 2013, 01:29:55 PM »
Thank you for doing this, Wipneus. It is informative and fascinating.

Wipneus

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Re: Home brew AMSR2 extent & area calculation
« Reply #92 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

Wipneus

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Re: Home brew AMSR2 extent & area calculation
« Reply #93 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)


jdallen

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Re: Home brew AMSR2 extent & area calculation
« Reply #94 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?
This space for Rent.

Wipneus

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Re: Home brew AMSR2 extent & area calculation
« Reply #95 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 )

jdallen

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Re: Home brew AMSR2 extent & area calculation
« Reply #96 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?
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Wipneus

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Re: Home brew AMSR2 extent & area calculation
« Reply #97 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.)


crandles

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Re: Home brew AMSR2 extent & area calculation
« Reply #98 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)

Wipneus

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Re: Home brew AMSR2 extent & area calculation
« Reply #99 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