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Re: Home brew AMSR2 extent & area calculation
« Reply #1100 on: August 01, 2014, 04:25:58 PM »
Thanks for these daily updates and animations. This melt season continues to fascinate me.  It looks as if the CAB is launching a strong defense as ice in the peripheral seas moves into the CAB. This trend has been in place for some time. SIA in the CAB is hanging in there.

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Re: Home brew AMSR2 extent & area calculation
« Reply #1101 on: August 02, 2014, 07:53:46 AM »
Update 20140801.

Extent: -46k2 (+118k vs 2013, +610k vs 2012)
Area: -108k9 (+347k vs 2013, +809k vs 2012)

Strong area decline reduces the big lag with 2013. The area drop takes place in the CAA, ESS and CAB. Only in the CAA the extent drops similarly. In the Greenland Sea the sea ice is increasing, both area and extent.

You will find the updated graphs in the top post

The details (in 1000 km2):


Extent:
   Central Arctic Basin       East Siberian Sea              Laptev Sea
                   -0.5                   -11.5                    -1.6
               Kara Sea             Barents Sea           Greenland Sea
                   -7.3                    -5.4                    21.6
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -6.9                     0.0                     8.2
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                  -23.5                   -12.3                    -5.5
             Bering Sea          Sea of Okhotsk            Total Extent
                   -0.7                    -0.8                   -46.2

Area:
   Central Arctic Basin       East Siberian Sea              Laptev Sea
                  -32.4                   -36.8                    -2.3
               Kara Sea             Barents Sea           Greenland Sea
                    5.8                    -6.3                    20.8
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -5.3                     0.0                    -0.6
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                  -39.3                    -5.7                    -5.5
             Bering Sea          Sea of Okhotsk              Total Area
                   -0.6                    -0.7                  -108.9


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Re: Home brew AMSR2 extent & area calculation
« Reply #1102 on: August 02, 2014, 08:17:08 AM »
Region of today is the Canadian Archipelago. There is plenty of darkening ( caused by melt) in the central channels. A few "arches" seems to indicate some om the ice is breaking away from the solid pack.

 

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Re: Home brew AMSR2 extent & area calculation
« Reply #1103 on: August 02, 2014, 08:29:00 AM »
An animation of the Kara region. In a steady decline leaves less and less ice to block the North (East) passage.

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Re: Home brew AMSR2 extent & area calculation
« Reply #1104 on: August 02, 2014, 01:41:27 PM »
Yes, it looks like winds will soon clear a passage north and east of Severnaya Zemlya: likely a narrow window in both breadth and time.
     As for the NWP, the eastern part will continue to melt out over the next several days, but shippers might need to make do with following in the wake of the small sloop Gjøa from 1905.
« Last Edit: August 02, 2014, 02:07:00 PM by iceman »

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Re: Home brew AMSR2 extent & area calculation
« Reply #1105 on: August 03, 2014, 08:35:20 AM »
Update 20140802.

Extent: -72k3 (+126k vs 2013, +643k vs 2012)
Area: -121k0 (+254k vs 2013, +787k vs 2012)

Declines in extent and area continue, but regionally there are differences. By extent the largest changes are In the Kara and ESS seas. By area look at CAB, Beaufort, Chukchi and CAA.
 
You will find the updated graphs in the top post

The details (in 1000 km2):


Extent:
   Central Arctic Basin       East Siberian Sea              Laptev Sea
                   -5.1                   -16.4                    -4.1
               Kara Sea             Barents Sea           Greenland Sea
                  -24.7                     3.9                   -13.6
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -4.0                     0.0                    -6.1
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   -3.4                    -6.0                     7.1
             Bering Sea          Sea of Okhotsk            Total Extent
                    0.0                     0.0                   -72.3

Area:
   Central Arctic Basin       East Siberian Sea              Laptev Sea
                  -49.6                    -8.5                    -3.9
               Kara Sea             Barents Sea           Greenland Sea
                    2.2                     9.8                   -15.2
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -2.3                     0.0                     0.7
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                  -15.6                   -22.9                   -15.7
             Bering Sea          Sea of Okhotsk              Total Area
                    0.0                     0.0                  -121.0


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Re: Home brew AMSR2 extent & area calculation
« Reply #1106 on: August 03, 2014, 08:47:00 AM »
Despite the 2014 hiatus appears to be shorter than in 2013, it is still 2013 that leads the melt. Maybe it is interesting to see the regional differences.

In the following it is clear that only Laptev and Beaufort 2014 is leading, in most of the other regions 2013 had clearly less ice. The ESS is an exception: by extent there was less ice on August 2 2014, but area (the concentration) is far higher.

The details (in 1000 km2):

#### EXTENT ASMR2 3.125 km DAYS 20140802 - 20130802 ####

   Central Arctic Basin       East Siberian Sea              Laptev Sea
                  131.4                   -18.1                  -157.0
               Kara Sea             Barents Sea           Greenland Sea
                   28.1                    52.4                    79.8
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                  -13.5                     0.0                     5.3
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   10.6                   -63.7                    70.7
             Bering Sea          Sea of Okhotsk            Total Extent
                    0.0                     0.0                   126.0

#### AREA ASMR2 3.125 km DAYS 20140802 - 20130802 ####

   Central Arctic Basin       East Siberian Sea              Laptev Sea
                  207.3                    93.8                  -138.2
               Kara Sea             Barents Sea           Greenland Sea
                    9.1                    41.9                    48.4
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -8.5                     0.0                     1.4
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   13.7                   -87.2                    72.2
             Bering Sea          Sea of Okhotsk              Total Area
                    0.0                     0.0                   253.9

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Re: Home brew AMSR2 extent & area calculation
« Reply #1107 on: August 03, 2014, 08:57:02 AM »
Region of the day is the ESS. Progress in melting is going on at a steady but not very fast rate.

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Re: Home brew AMSR2 extent & area calculation
« Reply #1108 on: August 04, 2014, 08:46:35 AM »
Update 20140803.

Extent: -90k0 (+105k vs 2013, +755k vs 2012)
Area: -83k8 (+210k vs 2013, +759k vs 2012)

Strong melt from Chukchi, via ESS and Laptev to the Kara Sea's. The Beaufort has an uptick, especially area.

(internet is extremely flaky today, images may take a while to post. On to the next try to post this)
 
You will find the updated graphs in the top post

The details (in 1000 km2):


Extent:
   Central Arctic Basin       East Siberian Sea              Laptev Sea
                   -6.2                   -29.4                   -10.0
               Kara Sea             Barents Sea           Greenland Sea
                   -9.9                     3.3                    -9.7
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -1.6                     0.0                    -2.8
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                  -16.3                     7.2                   -14.5
             Bering Sea          Sea of Okhotsk            Total Extent
                    0.0                     0.0                   -90.0

Area:
   Central Arctic Basin       East Siberian Sea              Laptev Sea
                   10.7                   -23.6                    -6.7
               Kara Sea             Barents Sea           Greenland Sea
                  -20.1                     1.4                   -15.9
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -1.0                     0.0                    -6.7
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                  -12.2                    21.7                   -31.4
             Bering Sea          Sea of Okhotsk              Total Area
                    0.0                     0.0                   -83.8


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Re: Home brew AMSR2 extent & area calculation
« Reply #1109 on: August 04, 2014, 09:08:53 AM »
Chukchi was image of the day just three days ago, now again as the polynya are now getting wider and wider.
I'd say it has to do with the winds that diverge the ice: to the west in Chukchi and to he east in the Beaufort.

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Re: Home brew AMSR2 extent & area calculation
« Reply #1110 on: August 05, 2014, 07:21:11 AM »
Update 20140804.

Extent: -68k1 (+78k vs 2013, +784k vs 2012)
Area: -119k8 (+149k vs 2013, +787k vs 2012)

Extent declines fast in the ESS, changes in other regions are much smaller. Area is also dropping fast in the ESS but also the CAB and Beaufort.
 
You will find the updated graphs in the top post

The details (in 1000 km2):


Extent:
   Central Arctic Basin       East Siberian Sea              Laptev Sea
                   -9.4                   -26.6                    -2.7
               Kara Sea             Barents Sea           Greenland Sea
                   -4.7                     4.1                    -4.3
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -2.0                     0.0                   -10.6
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   -3.9                     0.4                    -8.5
             Bering Sea          Sea of Okhotsk            Total Extent
                    0.0                     0.0                   -68.1

Area:
   Central Arctic Basin       East Siberian Sea              Laptev Sea
                  -48.5                   -34.6                    -1.8
               Kara Sea             Barents Sea           Greenland Sea
                   -2.2                     1.6                    -3.8
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -2.2                     0.0                    -4.7
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                    9.1                   -23.4                    -9.5
             Bering Sea          Sea of Okhotsk              Total Area
                    0.0                     0.0                  -119.8


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Re: Home brew AMSR2 extent & area calculation
« Reply #1111 on: August 05, 2014, 07:40:57 AM »
The ice in the Kara sea keeps declining. A lot of ice is still blocking the Vilkitskiy Strait as part of the Northern Sea Route to open. More ice than last year when eventually the strait opened for a few days only.

 

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Re: Home brew AMSR2 extent & area calculation
« Reply #1112 on: August 06, 2014, 07:43:20 AM »
Update 20140805.

Extent: -25k6 (+95k vs 2013, +1004k vs 2012)
Area: -35k4 (+188k vs 2013, +895k vs 2012)

Slow decline increases the lag with 2012 extent to one million. It is the ESS that is dropping extent and especially area. The Beaufort had a noticable increase in area.
 
You will find the updated graphs in the top post

The details (in 1000 km2):


Extent:
   Central Arctic Basin       East Siberian Sea              Laptev Sea
                   -1.6                   -17.1                    -0.8
               Kara Sea             Barents Sea           Greenland Sea
                   -6.8                     3.4                     5.5
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                    0.2                     0.0                    -4.3
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                  -12.4                     7.2                     1.0
             Bering Sea          Sea of Okhotsk            Total Extent
                    0.0                     0.0                   -25.6

Area:
   Central Arctic Basin       East Siberian Sea              Laptev Sea
                    9.0                   -50.6                    -1.8
               Kara Sea             Barents Sea           Greenland Sea
                   -8.7                     2.8                     2.4
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                    0.8                     0.0                     0.2
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                  -27.6                    34.9                     3.1
             Bering Sea          Sea of Okhotsk              Total Area
                    0.0                     0.0                   -35.4


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Re: Home brew AMSR2 extent & area calculation
« Reply #1113 on: August 06, 2014, 08:31:32 AM »
Images from the Canadian Archipelago today. The ice in the central part of the Parry Channel still looks solid, PIOMAS July data shows 0.5 m thicker ice than in 2013. Changes can go fast at this time of year. The crack just above the islands has opened again.

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Re: Home brew AMSR2 extent & area calculation
« Reply #1114 on: August 06, 2014, 08:42:16 AM »
The following animation shows that some ice is going for the exit called Fram Strait. More ice is taking the exit to the Barents Sea through the "Victoria Channel".

(clicking will start the animation)


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Re: Home brew AMSR2 extent & area calculation
« Reply #1115 on: August 06, 2014, 05:04:23 PM »
I suddenly have an irresistible urge to look at home brew DMI numbers. Have you by any chance been able to look into this over the last few months?

http://forum.arctic-sea-ice.net/index.php/topic,782.msg22214.html#msg22214
Reality is merely an illusion, albeit a very persistent one - Albert Einstein

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Re: Home brew AMSR2 extent & area calculation
« Reply #1116 on: August 06, 2014, 06:35:45 PM »
I suddenly have an irresistible urge to look at home brew DMI numbers. Have you by any chance been able to look into this over the last few months?

http://forum.arctic-sea-ice.net/index.php/topic,782.msg22214.html#msg22214

Actually I had a look a few days back. The problem is that ice concentration data is not available near the coast. Near the coast means something like less than 50km or so. That leaves very little ice in the Canadian Archipelago, and makes any comparison with other data hard. Elsewhere (NSIDC iirc) it is complained that properties of the algorithm that is used are not well known.

The "new extent graph" is not based on ice concentration but on ice type. Ice type is given as "no ice", "first year ice", "multi year ice", and "indeterminate". It uses SSMIS and radar data. I could not find an indication for the suitability of this data for the graph, nowhere the 15% cut-off is mentioned and I did not find why they think this data is suitable in the coastal zones. I am a bit doubtful about the DMI new extent graph, it looks different from other extent graphs.

For completeness there is an ice edge data set. Here the cut-off between open water and open ice seems to be 35%, very not standard.

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Re: Home brew AMSR2 extent & area calculation
« Reply #1117 on: August 06, 2014, 06:50:32 PM »
Re: DMI's interpretation of the OSI-SAF data

I am aware of it, and intend to use it as well at some time. If I remember correctly it is on a 10x10km grid. Grid cell area of such  a grid is a nut that I have already cracked, when the time comes you need it contact me.

Yes of course, I will start a thread for follow ups.

I think I do now need it, so please can I take you up on your most generous offer?


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Re: Home brew AMSR2 extent & area calculation
« Reply #1118 on: August 06, 2014, 07:09:40 PM »
I think I do now need it, so please can I take you up on your most generous offer?

Sure, I will put something together tomorrow.

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Re: Home brew AMSR2 extent & area calculation
« Reply #1119 on: August 06, 2014, 07:22:04 PM »
Many thanks Wipneus! Maybe we should revert the conversation to the Developers Corner?

http://forum.arctic-sea-ice.net/index.php/topic,782.0.html
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Re: Home brew AMSR2 extent & area calculation
« Reply #1120 on: August 07, 2014, 08:03:35 AM »
There is no update from Uni Hamburg as yet. Waiting....

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Re: Home brew AMSR2 extent & area calculation
« Reply #1121 on: August 07, 2014, 01:46:55 PM »
More ice is taking the exit to the Barents Sea through the "Victoria Channel".
A little early to call yet, but it looks like some of the thicker ice north of Svalbard will loosen up and join the Victoria Channel parade next week.

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Re: Home brew AMSR2 extent & area calculation
« Reply #1122 on: August 07, 2014, 04:52:45 PM »
Update 20140806.

Extent: -38k4 (+140k vs 2013, +1005k vs 2012)
Area: -83k3 (+146k vs 2013, +857k vs 2012)

In extent the changes are small with the CAB declining most (-15k). Big area drops in the ESS and CAB (-57k and -39k).
 
You will find the updated graphs in the top post

The details (in 1000 km2):


Extent:
   Central Arctic Basin       East Siberian Sea              Laptev Sea
                  -14.5                   -11.1                    -0.3
               Kara Sea             Barents Sea           Greenland Sea
                   -1.9                     4.4                   -14.1
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                    1.1                     0.0                     2.5
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                    0.1                     0.5                    -5.2
             Bering Sea          Sea of Okhotsk            Total Extent
                    0.0                     0.0                   -38.4

Area:
   Central Arctic Basin       East Siberian Sea              Laptev Sea
                  -39.0                   -56.7                    -1.2
               Kara Sea             Barents Sea           Greenland Sea
                    1.4                     6.1                    -3.9
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                    0.9                     0.0                    -0.3
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                    1.8                    12.4                    -4.9
             Bering Sea          Sea of Okhotsk              Total Area
                    0.0                     0.0                   -83.3


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Re: Home brew AMSR2 extent & area calculation
« Reply #1123 on: August 07, 2014, 05:05:47 PM »
Image of the day is the Greenland  Sea section. Transport through Fram seems to be stopped again. A few polynya opened in the central pack on the right of some big (largest is some 80km long) ice float. A small divergence in the wind field seems to be all that is needed.

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Re: Home brew AMSR2 extent & area calculation
« Reply #1124 on: August 07, 2014, 05:11:32 PM »
Image of the day is the Greenland  Sea section. Transport through Fram seems to be stopped again. A few polynya opened in the central pack on the right of some big (largest is some 80km long) ice float. A small divergence in the wind field seems to be all that is needed.

Any chance you could show a difference image for the ESS?

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Re: Home brew AMSR2 extent & area calculation
« Reply #1125 on: August 07, 2014, 05:57:04 PM »
The delta is not so informative today. As an animation the decaying ice look spectacular. There are some  "poofs" to be seen, eg the ice sheet that get dislodged from Wrangel island.

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Re: Home brew AMSR2 extent & area calculation
« Reply #1126 on: August 07, 2014, 10:03:11 PM »
The delta is not so informative today. As an animation the decaying ice look spectacular. There are some  "poofs" to be seen, eg the ice sheet that get dislodged from Wrangel island.
Wow, that's a spectacular animation. And just a week or so of melt.

You can see why extent hasn't dropped that much while area has. But if we get another week or so of this weather, a very large area is going to go "poof" and extent will drop dramatically.

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Re: Home brew AMSR2 extent & area calculation
« Reply #1127 on: August 08, 2014, 08:08:31 AM »
Update 20140807.

Extent: -57k9 (+163k vs 2013, +895k vs 2012)
Area: -128k7 (+19k vs 2013, +738k vs 2012)

Century in area brings 2014 close with 2013. I doubt it will lead by tomorrow: 2013 had a whopping -254k on 20130808.  Regionally the area in Beaufort, ESS and CAB dropped big way.
In extent not much changed, the biggest changes were outside the basin: Greenland Sea and Hudson region (in the Foxe Basin).
 
You will find the updated graphs in the top post

The details (in 1000 km2):


Extent:
   Central Arctic Basin       East Siberian Sea              Laptev Sea
                  -10.9                     0.8                    -4.6
               Kara Sea             Barents Sea           Greenland Sea
                   -5.6                    -3.0                   -13.5
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -0.5                     0.0                   -15.6
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   -0.7                    -5.2                     0.8
             Bering Sea          Sea of Okhotsk            Total Extent
                    0.0                     0.0                   -57.9

Area:
   Central Arctic Basin       East Siberian Sea              Laptev Sea
                  -28.2                   -31.7                    -4.6
               Kara Sea             Barents Sea           Greenland Sea
                   -7.7                    -6.7                    -1.3
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -0.3                     0.0                   -11.9
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                    5.1                   -39.0                    -2.3
             Bering Sea          Sea of Okhotsk              Total Area
                    0.0                     0.0                  -128.7


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Re: Home brew AMSR2 extent & area calculation
« Reply #1128 on: August 08, 2014, 08:24:34 AM »
Image of the day combines the Chukchi and East Siberian Sea's. A large area of lower concentration ice is visible.  There is clearly potential for more extent decline here, but as we have seen this year in the Beaufort, as we have seen in 2013, it may just as well survive.

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Re: Home brew AMSR2 extent & area calculation
« Reply #1129 on: August 08, 2014, 02:15:41 PM »
2013 had a whopping -254k on 20130808.

Wow! Do you happen to know why?
The Permian–Triassic extinction event, a.k.a. the Great Dying, occurred about 250 million years ago and is the most severe known extinction event. Up to 96% of all marine species and 70% of terrestrial vertebrate species became extinct; it is also the only known mass extinction of insects.

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Re: Home brew AMSR2 extent & area calculation
« Reply #1130 on: August 08, 2014, 02:55:35 PM »
2013 had a whopping -254k on 20130808.

Wow! Do you happen to know why?

This is not an answer but it  ended a two week "hiatus"  with very big melts in Greenland, Beaufort, ESS and the CAB.

Here are my comments at the time.

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Re: Home brew AMSR2 extent & area calculation
« Reply #1131 on: August 08, 2014, 04:02:48 PM »
Thanks.
The Permian–Triassic extinction event, a.k.a. the Great Dying, occurred about 250 million years ago and is the most severe known extinction event. Up to 96% of all marine species and 70% of terrestrial vertebrate species became extinct; it is also the only known mass extinction of insects.

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Re: Home brew AMSR2 extent & area calculation
« Reply #1132 on: August 09, 2014, 08:12:57 AM »
Update 20140808.

Extent: -104k1 (+195k vs 2013, +999k vs 2012)
Area: -60k8 (+212k vs 2013, +903k vs 2012)

A big drop in extent in the Pacific sector brings a century today.  Chukchi (-36k) and the CAB (-32k) area mostly affected.  If the similar area declines are an indication, this may be followed by more declines in the next days.
 
You will find the updated graphs in the top post

The details (in 1000 km2):


Extent:
   Central Arctic Basin       East Siberian Sea              Laptev Sea
                  -32.2                     0.3                     0.6
               Kara Sea             Barents Sea           Greenland Sea
                   -0.7                     4.0                   -13.1
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -3.7                     0.0                    -5.1
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                  -15.5                    -3.0                   -35.5
             Bering Sea          Sea of Okhotsk            Total Extent
                    0.0                     0.0                  -104.1

Area:
   Central Arctic Basin       East Siberian Sea              Laptev Sea
                  -29.9                    11.5                    -1.6
               Kara Sea             Barents Sea           Greenland Sea
                    3.4                    14.5                   -12.2
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -2.8                     0.0                    -3.4
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                  -10.9                     0.8                   -30.2
             Bering Sea          Sea of Okhotsk              Total Area
                    0.0                     0.0                   -60.8


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Re: Home brew AMSR2 extent & area calculation
« Reply #1133 on: August 09, 2014, 08:20:40 AM »
Close-up of Chukchi Sea with a large increase of "open" (less then 15% ice) water.

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Re: Home brew AMSR2 extent & area calculation
« Reply #1134 on: August 09, 2014, 09:42:36 AM »
As a peculiar extra, the crack between the central ice pack and the Canadian islands and Greenland is getting visible end to end.

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Re: Home brew AMSR2 extent & area calculation
« Reply #1135 on: August 09, 2014, 01:10:31 PM »
As a peculiar extra, the crack between the central ice pack and the Canadian islands and Greenland is getting visible end to end.
This is indeed odd.  Haven't the winds been blowing generally toward the islands for most of the past week?

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Re: Home brew AMSR2 extent & area calculation
« Reply #1136 on: August 09, 2014, 03:28:08 PM »
Close-up of Chukchi Sea with a large increase of "open" (less then 15% ice) water.

Finally!
The Permian–Triassic extinction event, a.k.a. the Great Dying, occurred about 250 million years ago and is the most severe known extinction event. Up to 96% of all marine species and 70% of terrestrial vertebrate species became extinct; it is also the only known mass extinction of insects.

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Re: Home brew AMSR2 extent & area calculation
« Reply #1137 on: August 09, 2014, 03:41:28 PM »

As a peculiar extra, the crack between the central ice pack and the Canadian islands and Greenland is getting visible end to end.

So now the NW-passage can start to open up since the transport of thicker ice than FYI (there's no thick ice left anywhere) is temporarily stopped by whatever process. Could also be this is just an artefact of tidal movements in the ocean and a particularly fortuitous pass of the satellite.
Cooling the outside by heat pump.

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Re: Home brew AMSR2 extent & area calculation
« Reply #1138 on: August 10, 2014, 08:26:04 AM »
Update 20140809.

Extent: -68k4 (+188k vs 2013, +972k vs 2012)
Area: -88k6 (+199k vs 2013, +971k vs 2012)

Declines in Chukchi continues but the biggest are found in the ESS . The concentration (area) loss in the ESS is especially indicative that more losses can be expected.
 
You will find the updated graphs in the top post

The details (in 1000 km2):


Extent:
   Central Arctic Basin       East Siberian Sea              Laptev Sea
                    3.3                   -38.5                    -3.5
               Kara Sea             Barents Sea           Greenland Sea
                   -7.1                    -1.3                     6.2
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                    1.5                     0.0                     5.6
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                    0.8                   -10.6                   -24.8
             Bering Sea          Sea of Okhotsk            Total Extent
                    0.0                     0.0                   -68.4

Area:
   Central Arctic Basin       East Siberian Sea              Laptev Sea
                  -13.2                   -53.2                     0.5
               Kara Sea             Barents Sea           Greenland Sea
                   -0.2                     0.9                     1.0
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                    1.5                     0.0                     0.8
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   -2.3                   -13.6                   -10.7
             Bering Sea          Sea of Okhotsk              Total Area
                    0.0                     0.0                   -88.6


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Re: Home brew AMSR2 extent & area calculation
« Reply #1139 on: August 10, 2014, 08:35:04 AM »
Normally not much reason to look at the Barents Sea at this time of year. However there is more ice there than has been usual lately.
The reason is ice that exits through the "Victoria Channel" rather than taking the more usual Fram Strait route.

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Re: Home brew AMSR2 extent & area calculation
« Reply #1140 on: August 11, 2014, 07:47:02 AM »
Update 20140810.

Extent: -73.4 (+170k vs 2013, +1027k vs 2012)
Area: -22k2 (+252k vs 2013, +1073k vs 2012)

Today's declines bring the lag with 2012 to over 1 million. The extent drop in the ESS continues, in the CAB a bit slower and not much more. Area decline is much slower now, it is getting cold up there.
 
You will find the updated graphs in the top post

The details (in 1000 km2):


Extent:
   Central Arctic Basin       East Siberian Sea              Laptev Sea
                  -14.0                   -31.7                    -5.2
               Kara Sea             Barents Sea           Greenland Sea
                   -3.5                     1.1                    -0.8
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -0.9                     0.0                    -2.6
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   -7.6                    -4.8                    -3.5
             Bering Sea          Sea of Okhotsk            Total Extent
                    0.0                     0.0                   -73.4

Area:
   Central Arctic Basin       East Siberian Sea              Laptev Sea
                  -10.6                    -3.4                    -3.8
               Kara Sea             Barents Sea           Greenland Sea
                   -4.7                    -3.7                     3.3
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -0.9                     0.0                    -0.2
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   -5.5                     6.5                     0.6
             Bering Sea          Sea of Okhotsk              Total Area
                    0.0                     0.0                   -22.2


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Re: Home brew AMSR2 extent & area calculation
« Reply #1141 on: August 11, 2014, 08:01:37 AM »
Looking at winds that may bring some heat from  lower latitudes into the Arctic, there is some from Siberia, over Laptev blowing into Kara. As can be seen here, the Vilkitzki Strait is being blown open and if sustained the North East Passage (proper ) can be open any time now.

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Re: Home brew AMSR2 extent & area calculation
« Reply #1142 on: August 11, 2014, 09:02:53 AM »
One thing about the great mobility of the ice pack this year is that extent and area drops do not always occur where the melting takes place.
The Beaufort is a case in point. For months the ice pack has been and is still the worst in the Basin. Yet the declines of extent and area have stood still for a long time.

The sequence here shows how that can go, although there is continuous melt occurring ice from north of the Canadian Islands is transported into the Beaufort.

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Re: Home brew AMSR2 extent & area calculation
« Reply #1143 on: August 11, 2014, 01:14:32 PM »
Loss of MYI and volume

Precisely so. This from GOFS 3.1.

(Click to animate)
« Last Edit: August 12, 2014, 09:05:24 AM by Jim Hunt »
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Re: Home brew AMSR2 extent & area calculation
« Reply #1144 on: August 11, 2014, 04:08:21 PM »
Wow, that is an amazing image sequence Jim! If you look careful you can see the thick MYI being squeezed into the Canadian Archipello. That also explains why the CA does not melt this year.
Looks like we are going to be left with almost no ice thicker than 2-3 meters by the end of this summer.

Is there comparison material from 2012?

DavidR

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Re: Home brew AMSR2 extent & area calculation
« Reply #1145 on: August 12, 2014, 06:25:56 AM »
Loss of MYI and volume

Precisely so. This from GOFS 3.1.

At the very  end of this sequence we can see that  the last of the 'thick' ice between Svarlbard and the North pole has pretty well all disappeared into the Barents and melted away. On MODIS we can see that ice in the Barents appears to be moving south at about  20 km a day but the ice front is only  moving south at about 5 km a day so there is a lot  of melting going on there even as area and extent  increase. 

The fact that  the ice around the North Pole is now exceptionally thin for hundreds of kilometers in all directions suggests there are still more interesting times to  come before the end of the season.   
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jdallen

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Re: Home brew AMSR2 extent & area calculation
« Reply #1146 on: August 12, 2014, 07:23:39 AM »
The fact that  the ice around the North Pole is now exceptionally thin for hundreds of kilometers in all directions suggests there are still more interesting times to  come before the end of the season.
My two cents as an armchair amateur...

Thin, but I'd say not quite thin enough.  There will be a huge volume loss, but I'm fairly confident we won't see an "ice free" north pole.  The Laptev Dagger may come a bit close(r) but I don't think it will arrive.  Over all, I don't think the thin ice will permit the melt to get much past 2013.  Bad enough in itself, but I don't anticipate anything sudden and dramatic; the net balance of heat entering the system is going to start dropping off sharply fairly soon.  To get to 2007/2011/2012 levels, the heat needed won't be around, and I'm confident import via currents (North Atlantic drift) won't make up the short fall.

I don't think that outcome is necessarily good for the Arctic.  The remaining thin ice will actually tend to impede the refreeze, providing insulation and reducing heat loss from the ocean, without necessarily contributing greatly itself to the volume.

The huge areas of open water in the Laptev, Barents and ESS will also tend to inhibit the refreeze.  The extent in the Laptev in particular is so huge, I'm concerned winter storms may be able to create enough surf that heat will be brought up from depth which will cripple the creation of ice until quite late - possibly after December.  I will be watching the mass balance numbers next spring with great interest.
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Wipneus

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Re: Home brew AMSR2 extent & area calculation
« Reply #1147 on: August 12, 2014, 07:51:41 AM »
Update 20140811.

Extent: -108k5 (+127k vs 2013, +1155k vs 2012)
Area: -45k1 (+242k vs 2013, +1113k vs 2012)

A extent century today, caused by continuing declines in the Chukchi/CAB/ESS/Laptev section. Area changes less, with the ESS even a increase.
 
You will find the updated graphs in the top post

The details (in 1000 km2):


Extent:
   Central Arctic Basin       East Siberian Sea              Laptev Sea
                  -32.7                   -26.4                    -9.2
               Kara Sea             Barents Sea           Greenland Sea
                   -5.6                     2.9                    -5.9
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -2.7                     0.0                    -0.9
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                  -13.5                     0.5                   -14.8
             Bering Sea          Sea of Okhotsk            Total Extent
                    0.0                     0.0                  -108.5

Area:
   Central Arctic Basin       East Siberian Sea              Laptev Sea
                  -15.0                    10.2                    -6.2
               Kara Sea             Barents Sea           Greenland Sea
                   -7.2                    -5.0                    -3.3
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -2.4                     0.0                     1.6
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                  -16.0                     5.6                    -7.4
             Bering Sea          Sea of Okhotsk              Total Area
                    0.0                     0.0                   -45.1


Wipneus

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Re: Home brew AMSR2 extent & area calculation
« Reply #1148 on: August 12, 2014, 08:00:32 AM »
Warm air from lower latitude enters the Arctic over the Laptev (and nowhere else according to earth.nullschool). No wonder the Laptev bite is getting bigger and bigger.

DavidR

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Re: Home brew AMSR2 extent & area calculation
« Reply #1149 on: August 12, 2014, 11:20:00 AM »
The fact that  the ice around the North Pole is now exceptionally thin for hundreds of kilometers in all directions suggests there are still more interesting times to  come before the end of the season.

Thin, but I'd say not quite thin enough.  There will be a huge volume loss, but I'm fairly confident we won't see an "ice free" north pole. 

I wasn't thinking we'd go quite that far, but there is a lot of ice in the Barents and north of that  in the Arctic that  is currently moving south at  10-20 km a day.  Eyeballing it  suggests about 500K km^2 that was open water at this time last year is now covered with some ice. Once it  gets into the Barents it is melting out very quickly. This suggests to me that we could see a late minimum as this ice continues to melt  out in late September.  As for the rest of the arctic I'd think that the ice that has gone south will leave lots of polynas and low extent  on the Atlantic side.
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