Home brew AMSR2 extent & area calculation

[Wipneus]

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

[Wipneus]

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)

[Wipneus]

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)

 

[Wipneus]

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

[Wipneus]

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)

[Wipneus]

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

[ChrisReynolds]

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

[Wipneus]

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

Thanks, I am busy reading about the differences between the different algorithms. This surely looks interesting.

[Wipneus]

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)

[Wipneus]

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

[Wipneus]

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)

[seaice.de]

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):

[Wipneus]

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

[Wipneus]

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)

[Wipneus]

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

[Wipneus]

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)

[Wipneus]

NE Greenland: did I miss Espen's announcement that that big broken off fast ice, is now broken in three pieces?

(log in etc):

[Wipneus]

Animation NE Greenland & Fram Sea Ice

(for those that have logged in)

[Wipneus]

Confirmation on Modis that BigBerg is no more.

(yes, need to log in)

[Neven]

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?

[Wipneus]

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.

[Artful Dodger]

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. 

[Wipneus]

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.

[ivica]

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.

[Wipneus]

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.

[ivica]

"Fiber" which connect us with the beach there works, just checked 

[Wipneus]

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)

[Wipneus]

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

[helorime]

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

[Wipneus]

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

[Wipneus]

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)

[AartBluestoke]

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?

[Wipneus]

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.

[Richard Rathbone]

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.

[Bob Wallace]

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.

[Wipneus]

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

[Wipneus]

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)

[Wipneus]

Region of the day is Greenland sea. Will it be ice free this year?

(log in to see)

[Neven]

More topics are being opened lately, and so I think it's time I stickify this one.

[Vergent]

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

[danp]

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

(overview of the whole image, along with a subset at full resolution:)

[jdallen]

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.

[Artful Dodger]

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?

[Wipneus]

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

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

[Wipneus]

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)

[Vergent]

Hi Verge,

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

Lodger,

It reminds me of this.



Verge

[Artful Dodger]

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. 

[Wipneus]

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:

[jdallen]

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.

[Wipneus]

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.