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Richard Rathbone

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Re: Home brew AMSR2 extent & area calculation
« Reply #1400 on: January 01, 2015, 08:02:07 PM »
Thanks for these updates over the past year Wipneus.

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Re: Home brew AMSR2 extent & area calculation
« Reply #1401 on: January 02, 2015, 04:50:21 PM »
Thanks for these updates over the past year Wipneus.

Thanks from me  as  well. I visit this thread daily.

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Re: Home brew AMSR2 extent & area calculation
« Reply #1402 on: January 08, 2015, 08:13:38 AM »
Update 20150107.
Changes from 20141231.

Extent: +130.0 (+7k vs 2014, +126k vs 2013)
Area: +97.2 (-29k vs 2014, +203k vs 2013)

Another week with slow increase (17 k/day) of Arctic sea ice brings us close to the level of previous years. Regionally there are big differences as is illustrated on the attached changes map. Most of the ice growth is in the Baffin/New Foundland and the Okhotsk regions, while ice declined in the Greenland, Barents and Bering regions. Winds are favoring this development, most notable are the southerly winds of Pacific origin  over the Bering, Chukchi and the East Siberian Seas. Cold is transported from West Siberia over the Laptev and Kara Seas.

 
You will find the updated graphs in the top post

The details (in 1000 km2):


Extent:
   Central Arctic Basin       East Siberian Sea              Laptev Sea
                   -9.0                    -2.8                    -4.1
               Kara Sea             Barents Sea           Greenland Sea
                    2.2                   -59.1                   -40.8
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                  164.7                     1.3                    69.3
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                    1.7                     2.9                    -4.8
             Bering Sea          Sea of Okhotsk            Total Extent
                  -55.6                    64.2                   130.0

Area:
   Central Arctic Basin       East Siberian Sea              Laptev Sea
                  -34.0                   -17.5                   -12.5
               Kara Sea             Barents Sea           Greenland Sea
                    8.2                   -84.0                   -40.4
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                  137.0                     0.5                   138.1
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                    4.4                    12.0                   -10.8
             Bering Sea          Sea of Okhotsk              Total Area
                  -68.0                    64.1                    97.2


Wipneus

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Re: Home brew AMSR2 extent & area calculation
« Reply #1403 on: January 08, 2015, 08:33:50 AM »
A big decline of the ice in the Barents Sea caused by persistent low pressure south of Svalbard. The familiar open water North of the islands widens again.

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Re: Home brew AMSR2 extent & area calculation
« Reply #1404 on: January 11, 2015, 09:31:05 AM »
The sea ice in the East Siberian Sea is mostly still mobile except very near the coast and bhind the New Siberian Islands. A year ago most of this ice was solid and kept together long into the melting season.

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Re: Home brew AMSR2 extent & area calculation
« Reply #1405 on: January 12, 2015, 08:35:03 AM »
A look at the Fram Strait shows that the transport has temporary stopped. Eastern winds caused by rising air pressure over Svalbard cause compaction of the ice in place.

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Re: Home brew AMSR2 extent & area calculation
« Reply #1406 on: January 14, 2015, 07:37:19 AM »
Sequence of North Greenland. The cracking caused by some weak polar lows is surprising, perhaps it is more a reaction to the absence of strong northerly flow. The extent of the collapsing Nares Strait arch (in the Lincoln Sea) can be appreciated.

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Re: Home brew AMSR2 extent & area calculation
« Reply #1407 on: January 14, 2015, 02:00:41 PM »
Wipneus,

Thanks for sharing your resources and talents on tracking ice. From your observations and the IR imagery, it seems the sea ice is more unstable and moving this year - despite the lack of Fram discharge. It seems that the subsurface ocean temps and winds is having an impact on ice formation and stability across the Arctic basin.

A4R

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Re: Home brew AMSR2 extent & area calculation
« Reply #1408 on: January 14, 2015, 03:19:56 PM »
A couple from yesterday's Wokingham Weather sat images;

Beaufort    http://www.woksat.info/etcxa13/xa13-1450-g-arc.html

and Lincoln   http://www.woksat.info/etcxa13/xa13-1310-h-grn-n.html
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Re: Home brew AMSR2 extent & area calculation
« Reply #1409 on: January 14, 2015, 05:37:45 PM »
A couple from yesterday's Wokingham Weather sat images;

Beaufort    http://www.woksat.info/etcxa13/xa13-1450-g-arc.html

and Lincoln   http://www.woksat.info/etcxa13/xa13-1310-h-grn-n.html

Great images, Gray Wolf, and ditto A4R.

Here's the Beaufort for the same date in 2012, same satellite.

http://www.woksat.info/etcua15/ua15-1416-d-arc.html
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Re: Home brew AMSR2 extent & area calculation
« Reply #1410 on: January 14, 2015, 07:02:10 PM »
Wipneus,

Thanks for sharing your resources and talents on tracking ice. From your observations and the IR imagery, it seems the sea ice is more unstable and moving this year - despite the lack of Fram discharge. It seems that the subsurface ocean temps and winds is having an impact on ice formation and stability across the Arctic basin.

A4R

A4R, I started to look more closely at the ice movements when the Uni Hamburg made their fantastic hi resolution sea ice concentration data (based on Jaxa's superb AMSR2 microwave measurements) available.
This is the start of the third year with that data. In between the ice has always been remarkably mobile.
At least we can say that despite the increase in volume most of the ice at the moment is not less mobile than in the two years before. Exception may be the East Siberian Sea where the ice is more mobile now and perhaps the Canadian Archipelago core that looks very solid frozen at the moment.

Attached is what happened to the ice in the Beaufort nearly two years ago.

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Re: Home brew AMSR2 extent & area calculation
« Reply #1411 on: January 15, 2015, 07:18:11 AM »
Update 20150114.
Changes from 20150107.

Extent: +239.4 (+38k vs 2014, +57k vs 2013, +80k vs 2012)
Area: +203.5 (+90k vs 2014, +185k vs 2013, +202k vs 2012)

At first the week started with very slow or nil ice changes, but the increase has picked up to near century daily changes. Ice area and extent figures are now at levels comparable with 2012, 2013 and 2014. The weekly average was about 35k/day. Reason is that the conditions for ice compaction - southerly winds in the Pacific, Baffin and Barents regions - are much reduced so the "normal" freezing in those regions did resume. Noteworthy is the stall in Fram Strait export, the winds blew mostly from the east causing compacting of the ice in the Greenland Sea.
 
You will find the updated graphs in the top post

The details (in 1000 km2):


Extent:
   Central Arctic Basin       East Siberian Sea              Laptev Sea
                   -9.8                     2.2                     3.7
               Kara Sea             Barents Sea           Greenland Sea
                    2.1                   118.8                   -48.6
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                  104.9                    28.2                   -13.5
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                    6.3                     0.0                    -2.2
             Bering Sea          Sea of Okhotsk            Total Extent
                   66.7                   -19.2                   239.4

Area:
   Central Arctic Basin       East Siberian Sea              Laptev Sea
                   18.1                    12.9                    11.2
               Kara Sea             Barents Sea           Greenland Sea
                    4.4                   105.3                   -44.6
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   99.7                    15.9                   -26.3
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                    0.2                    -1.0                     3.0
             Bering Sea          Sea of Okhotsk              Total Area
                   52.7                   -48.1                   203.5


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Re: Home brew AMSR2 extent & area calculation
« Reply #1412 on: January 15, 2015, 07:26:25 AM »
Winds are transporting cold continental air into the Arctic over the Laptev region. This has been a constant part of the Arctic weather patterns for weeks now. In the attached animation some of the working of the resulting ice engine can be seen, the lateral ice growth of the thin ice is of course invisible. The mobility in the Laptev Sea is comparable with last year.

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Re: Home brew AMSR2 extent & area calculation
« Reply #1413 on: January 22, 2015, 07:39:46 AM »
Update 20150121.
Changes from 20150114.



Extent: +323.9 (-1k vs 2014, -11k vs 2013, +17k vs 2012)
Area: +368.2 (+34k vs 2014, +113k vs 2013, +125k vs 2012)

This week the ice extent and area increased vigorously at first and then slowed, giving an average increase of about 50k/day. The total sea ice extent and area numbers are comparable with the last three years.
Regionally the growth was shared by most "ice edge regions". That is the Bering and Okhotsk regions on the Pacific side and Baffin, Greenland Sea and Barents Sea regions facing the Atlantic. Winds blowing away from the Arctic help the ice expanding. Cold air (though less cold than previously this winter) enters the Arctic from the Eurasian continent.
 
You will find the updated graphs in the top post

The details (in 1000 km2):


Extent:
   Central Arctic Basin       East Siberian Sea              Laptev Sea
                   14.4                     0.7                     0.5
               Kara Sea             Barents Sea           Greenland Sea
                   -4.7                    42.9                    65.2
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   30.1                     1.8                    14.1
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   -1.7                     0.0                     3.0
             Bering Sea          Sea of Okhotsk            Total Extent
                   83.3                    74.4                   323.9

Area:
   Central Arctic Basin       East Siberian Sea              Laptev Sea
                   26.4                     4.9                     5.2
               Kara Sea             Barents Sea           Greenland Sea
                  -11.9                    61.3                    54.4
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   35.3                    -1.5                    30.0
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                    2.0                     0.1                     8.3
             Bering Sea          Sea of Okhotsk              Total Area
                   88.0                    65.8                   368.2


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Re: Home brew AMSR2 extent & area calculation
« Reply #1414 on: January 22, 2015, 07:50:45 AM »
A ten day animation of the Beaufort region, as usual contrast enhanced to bring out the movements of the ice. There is a clear movement of ice moving along the Alaskan coast to Chukchi.
Source of this ice seems not to be the thick multi year ice packed against the  Canadian Archipelago, but more from the north. Thus the ice making a kind of u-turn.

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Re: Home brew AMSR2 extent & area calculation
« Reply #1415 on: January 29, 2015, 07:43:17 AM »
Update 20150128.
Changes from 20150121.

Extent: +174.5 (-27k vs 2014, -131k vs 2013, -94k vs 2012)
Area: +219.6 (+107k vs 2014, -12k vs 2013, +60k vs 2012)

Refreezing slowed down to about 25k/day. Most of this is on the Pacific side, winds mostly from the north caused the Bering and Okhotsk regions to surge. The Atlantic "front" was overall quiet, ice in the Greenland sea was compacted due to winds from the east.

No Polar Portal image this week, they have stopped updating.
 
You will find the updated graphs in the top post

The details (in 1000 km2):


Extent:
   Central Arctic Basin       East Siberian Sea              Laptev Sea
                  -27.2                     0.0                     0.3
               Kara Sea             Barents Sea           Greenland Sea
                    5.0                   -12.9                   -62.0
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   12.7                    15.6                     2.8
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                    1.7                     0.0                     4.9
             Bering Sea          Sea of Okhotsk            Total Extent
                  134.9                    98.7                   174.5

Area:
   Central Arctic Basin       East Siberian Sea              Laptev Sea
                  -42.9                    -0.1                     0.1
               Kara Sea             Barents Sea           Greenland Sea
                    8.0                   -14.3                   -45.5
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   17.9                    11.9                     0.6
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                    0.3                    -1.0                    17.6
             Bering Sea          Sea of Okhotsk              Total Area
                  122.1                   144.8                   219.6


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Re: Home brew AMSR2 extent & area calculation
« Reply #1416 on: January 29, 2015, 07:51:41 AM »
Animation of the St.Lawrence region. You can see that the ASI algorithm, used by the Uni Hamburg sea ice concentration calculation, has some day to day difficulty with the active winter weather.  There are some false ice flashes and sudden increases in concentration. Most of the ice is real though, what cannot be always said with other sea ice concentration products.

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Re: Home brew AMSR2 extent & area calculation
« Reply #1417 on: February 05, 2015, 08:22:49 AM »
Update 20150204.
Changes from 20150128.

Extent: +248.7 (+95k vs 2014, -18k vs 2013, +241k vs 2012)
Area: +156.0 (+246k vs 2014, -89k vs 2013, +293k vs 2012)

Extent and area had a small dip in the middle of last week, but increased on average by about  35k/day (extent) and 20k/day (area). Levels are below 2013 but above those in 2012 and 2014 but the differences are small and probably not significant. Increases where all on the Atlantic side, the Barents region is responsible for most of the increase, but also the St. Lawrence, Baffin and Greenland Sea regions did increase. On the Pacific side the Bering and Sea of Okhotsk regions saw declines. Looking at the PolarPortal map, wind and temperatures seem to be causing this pattern with a relatively cold pole above Kara and a warm spot near the Bering Strait.

You will find the updated graphs in the top post

The details (in 1000 km2):


Extent:
   Central Arctic Basin       East Siberian Sea              Laptev Sea
                    5.0                     0.0                    -0.1
               Kara Sea             Barents Sea           Greenland Sea
                   -0.4                   140.1                    54.7
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   44.5                    62.2                     0.1
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                    0.3                     0.0                    -1.7
             Bering Sea          Sea of Okhotsk            Total Extent
                  -31.3                   -24.5                   248.7

Area:
   Central Arctic Basin       East Siberian Sea              Laptev Sea
                   17.7                    -3.4                    -3.1
               Kara Sea             Barents Sea           Greenland Sea
                    6.0                   125.9                    46.7
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   56.1                    66.4                     3.1
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   -2.5                    -3.9                   -12.6
             Bering Sea          Sea of Okhotsk              Total Area
                  -61.7                   -78.6                   156.0


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Re: Home brew AMSR2 extent & area calculation
« Reply #1418 on: February 05, 2015, 08:28:11 AM »
The ice in the Sea of Okhotsk is mobile moving with the winds that are blowing mostly from the north.

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Re: Home brew AMSR2 extent & area calculation
« Reply #1419 on: February 07, 2015, 04:11:08 PM »
Slow expanding sea ice in the Barents Sea suddenly reverses by southern winds blowing with speeds upto 60km/h.

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Re: Home brew AMSR2 extent & area calculation
« Reply #1420 on: February 07, 2015, 09:12:22 PM »
These animations suggest that we will see quite a low maximum extent  and area this year. The two areas that  can provide significant increases both  appear to contain thin highly  mobile ice. The Northern Pacific has been exceptionally warm for the last 8 months and was significantly warmer than any year in the past decade in January.  Based on this latest animation of the Barents  the ice appears highly mobile but we can't expect an  equally  rapid expansion of the ice back to the areas it has just been cleared out  of. 
Toto, I've a feeling we're not in Kansas anymore

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Re: Home brew AMSR2 extent & area calculation
« Reply #1421 on: February 08, 2015, 12:01:36 PM »
Continuing eastward, strong, cold continental winds stir the ice in the East Siberian and Laptev Seas. There is far more mobile ice in the ESS compared to last year.

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Re: Home brew AMSR2 extent & area calculation
« Reply #1422 on: February 12, 2015, 08:47:32 AM »
Update 20150211.
Changes from 20150204.

Extent: +94.4 (+344k vs 2014, -121k vs 2013, +125k vs 2012)
Area: -88.6 (+335k vs 2014, -213k vs 2013, +208k vs 2012)

Extent increase slowed down. Area actually decreased with the same  rate, about 13k/day. Again the winds explain most of the changes (together with ongoing freezing in places). Biggest change is a decline in the Barents Sea, smaller increases in the Bering and Sea of Okhotsk regions as well as the Baffin and Gulf of St. Lawrence on the Atlantic side. The anomaly in area decline is mostly found in the Central Arctic, winds from the Eurasian blow to the Canadian Islands, leaving some open water in the east and presumably thickening by compacting and ridging in the west.
 
You will find the updated graphs in the top post

The details (in 1000 km2):


Extent:
   Central Arctic Basin       East Siberian Sea              Laptev Sea
                   -8.5                     0.0                   -13.9
               Kara Sea             Barents Sea           Greenland Sea
                  -20.0                  -124.8                    67.8
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   44.2                    65.6                    -0.3
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                    1.5                     0.0                     1.2
             Bering Sea          Sea of Okhotsk            Total Extent
                   86.7                    -5.2                    94.4

Area:
   Central Arctic Basin       East Siberian Sea              Laptev Sea
                  -62.6                     3.4                   -31.1
               Kara Sea             Barents Sea           Greenland Sea
                  -50.1                  -131.5                    29.7
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   42.8                    39.0                     1.7
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                    3.3                     1.1                     8.4
             Bering Sea          Sea of Okhotsk              Total Area
                   10.9                    46.5                   -88.6


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Re: Home brew AMSR2 extent & area calculation
« Reply #1423 on: February 12, 2015, 08:59:48 AM »
Animation of the Bering Sea region, compared with 2013. The influence of the northern winds is clearly visible: the small amount of ice extends and drops in concentration.

(click to animate)

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Re: Home brew AMSR2 extent & area calculation
« Reply #1424 on: February 12, 2015, 05:24:13 PM »
Animation of the Bering Sea region, compared with 2013. The influence of the northern winds is clearly visible: the small amount of ice extends and drops in concentration.

(click to animate)

Wow.

It actually looks to be melting as it is swept away from the coast.  I think the Bering is still just to warm to permit ice growth.  You can see further evidence of this if you look at the Aleutians.  In 2013 there is obvious fast ice along the north sides of most of the chain.  This year, there is none.

So here is a question:  What will the effect on the season be if, as it appears possible, there is no further growth of the Bering pack, and it melts out by late April/early May?... or even earlier!
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Re: Home brew AMSR2 extent & area calculation
« Reply #1425 on: February 16, 2015, 08:35:43 AM »
The race to Fram Strait.

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Re: Home brew AMSR2 extent & area calculation
« Reply #1426 on: February 16, 2015, 11:13:08 AM »
Well Fram has certainly been running 'within normal parameters' since mid december? Should this behaviour persist into melt season then we will see a very different outcome in Sept than the last couple of years. We also seem to have shed all the 'retained ice' we saved over those two years leaving the Atlantic side pretty much all FY ice now?
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Re: Home brew AMSR2 extent & area calculation
« Reply #1427 on: February 19, 2015, 08:19:51 AM »
Update 20150218.
Changes from 20150211.

Extent: -33.9 (+140k vs 2014, -400k vs 2013, -122k vs 2012)
Area: +106.5 (+289k vs 2014, -454k vs 2013, +66k vs 2012)

Ice growth started slow this week followed by declines in the last three days. Over seven days total extent dropped a little and area increased by a moderate amount. Regionally the declines where on all regions on the Atlantic side with marginal ice. The ice in the Pacific regions, Bering and Sea of Okhotsk, actually increased. Finally century declines at the end of the freezing season are not unique in the "home brew" sea ice series. Compare the current decline, now at -184k in three days, with that in 2014 when extent declined -323k in three days (March 6-9).
 
You will find the updated graphs in the top post

The details (in 1000 km2):


Extent:
   Central Arctic Basin       East Siberian Sea              Laptev Sea
                  -15.2                     0.0                     7.1
               Kara Sea             Barents Sea           Greenland Sea
                    2.3                   -24.6                    -1.0
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                  -18.5                   -39.7                     4.5
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   -3.7                    -0.7                     0.0
             Bering Sea          Sea of Okhotsk            Total Extent
                   38.9                    17.0                   -33.9

Area:
   Central Arctic Basin       East Siberian Sea              Laptev Sea
                   -8.3                    -0.7                    16.1
               Kara Sea             Barents Sea           Greenland Sea
                    2.1                   -14.1                     2.4
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                  -20.0                   -20.2                     1.8
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                  -12.0                    -1.2                     1.4
             Bering Sea          Sea of Okhotsk              Total Area
                  136.9                    22.2                   106.5


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Re: Home brew AMSR2 extent & area calculation
« Reply #1428 on: February 19, 2015, 08:32:26 AM »
A sequence of the Laptev Sea. Peculiar darkening of the landfast ice can be seen. Last year it was suggested due to river water or smoke from forest fires. For that it is far too early now.

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Re: Home brew AMSR2 extent & area calculation
« Reply #1429 on: February 20, 2015, 08:59:22 AM »
Ice in the Beaufort was tightly locked in place by northern winds. Now the winds have turned, the cracks re-appear, nothing like the Great Cracking Event in 2013 yet.

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Re: Home brew AMSR2 extent & area calculation
« Reply #1430 on: February 26, 2015, 07:29:48 AM »
Update 20150225.
Changes from 20150218.

Extent: +66.0 (-46k vs 2014, -508k vs 2013, -213k vs 2012)
Area: -5.3 (-3k vs 2014, -621k vs 2013, -58k vs 2012)

A moderate increase in total extent, while total area is almost unchanged, cause the 2015 levels to be the lowest in the last four years. Winter freezing power is low with relatively mild temperatures over most of the Arctic, so most of the regional changes are due to the local wind fields. The ice in the Bering Sea declined strongly while in some regions on the Atlantic side, St.Lawrence, Baffin and  Greenland Sea regions, the sea ice increased.

 
You will find the updated graphs in the top post

The details (in 1000 km2):


Extent:
   Central Arctic Basin       East Siberian Sea              Laptev Sea
                   39.2                    -0.4                     3.0
               Kara Sea             Barents Sea           Greenland Sea
                    0.5                    -2.4                    11.1
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   31.6                    49.2                    -0.9
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   -0.4                    -0.9                    -5.6
             Bering Sea          Sea of Okhotsk            Total Extent
                  -75.1                    17.0                    66.0

Area:
   Central Arctic Basin       East Siberian Sea              Laptev Sea
                   62.9                    -9.1                     7.2
               Kara Sea             Barents Sea           Greenland Sea
                   -6.1                    -3.2                    27.3
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   29.8                    32.2                    -5.3
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                  -18.6                    -6.9                   -22.5
             Bering Sea          Sea of Okhotsk              Total Area
                  -81.2                   -11.6                    -5.3

conv

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Re: Home brew AMSR2 extent & area calculation
« Reply #1431 on: February 26, 2015, 07:35:05 AM »
Local winds currently favor Fram Strait export.

(click the picture to animate)

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Re: Home brew AMSR2 extent & area calculation
« Reply #1432 on: February 27, 2015, 04:19:34 PM »
What's with the IJIS website?

http://www.ijis.iarc.uaf.edu/en/home/seaice_extent.htm

Have they set up a new website for reporting extent?  I usually visit this site daily.

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Re: Home brew AMSR2 extent & area calculation
« Reply #1433 on: February 27, 2015, 06:00:38 PM »
What's with the IJIS website?

http://www.ijis.iarc.uaf.edu/en/home/seaice_extent.htm

Have they set up a new website for reporting extent?  I usually visit this site daily.


In case anyone's looking: The new URL for daily IJIS extent update CSVs.

(And yes, we were down 2659 kmĀ² yesterday.)

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Re: Home brew AMSR2 extent & area calculation
« Reply #1435 on: February 27, 2015, 11:40:37 PM »
Local winds currently favor Fram Strait export.

Some brisk southerly winds along the Greenland coast forecast for early March.  The ice will be marching double-time for a few days in your next animation.

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Re: Home brew AMSR2 extent & area calculation
« Reply #1436 on: March 05, 2015, 08:23:07 AM »
Update 20150304.
Changes from 20150225.

Extent: -147.5 (-203k vs 2014, -597k vs 2013, -863k vs 2012)
Area: -113.0 (+32k vs 2014, -668k vs 2013, -760k vs 2012)

Both extent and area declined this week, on average about -20k/day. Regionally most of the declines were in the Barents, Bering and Greenland Seas. This brings total extent well below the previous years, but area is still a bit above 2014. The current maximum extent was reached at Feb 15 (16 for area), levels are now -250k (-360k for area) below this preliminary figures. That is not a gap that cannot be bridged, last year there was a week increase of over +500k  (Mar 9-16 2014), 2012 saw a similar jump. The winds have to cooperate of course, otherwise 2015 melting season will start with an extreme early (and low) maximum.
 
You will find the updated graphs in the top post

The details (in 1000 km2):


Extent:
   Central Arctic Basin       East Siberian Sea              Laptev Sea
                  -26.5                     0.4                     0.5
               Kara Sea             Barents Sea           Greenland Sea
                    5.2                   -99.7                   -36.1
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   35.1                    10.2                     0.0
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                    2.8                     0.6                     5.6
             Bering Sea          Sea of Okhotsk            Total Extent
                  -81.9                    36.5                  -147.5

Area:
   Central Arctic Basin       East Siberian Sea              Laptev Sea
                  -26.5                     6.0                     4.7
               Kara Sea             Barents Sea           Greenland Sea
                  -16.4                   -90.5                   -38.1
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   26.0                    17.0                     2.2
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   14.6                    -7.4                    14.9
             Bering Sea          Sea of Okhotsk              Total Area
                  -64.8                    45.2                  -113.0

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Re: Home brew AMSR2 extent & area calculation
« Reply #1437 on: March 05, 2015, 08:28:18 AM »
The Bering Sea region has seen an extremely variable ice cover. This week the ice declined, and you can see in the animation where some of the ice went: through the Strait towards Chukchi.

Click to start the animation.

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Re: Home brew AMSR2 extent & area calculation
« Reply #1438 on: March 05, 2015, 09:19:37 AM »
Would I be reading too much into thinking that could mean we could be getting a lot of under melt from the amount of warm water also being pushed into the Chukchi? Including in that the ice would be very salty ice and all that implies?
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Re: Home brew AMSR2 extent & area calculation
« Reply #1439 on: March 05, 2015, 04:49:50 PM »
Would I be reading too much into thinking that could mean we could be getting a lot of under melt from the amount of warm water also being pushed into the Chukchi? Including in that the ice would be very salty ice and all that implies?
To early I think, but the ice would be saline, and as such more vulnerable at lower temperature.
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Re: Home brew AMSR2 extent & area calculation
« Reply #1440 on: March 07, 2015, 09:07:21 AM »
Lots of ice moving in and around the Barents Sea. The compaction has contributed about 200k to the current decline.

(click to start the animation)

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Re: Home brew AMSR2 extent & area calculation
« Reply #1441 on: March 07, 2015, 11:26:30 AM »
One of the minor regions is the Baltic Sea. The ice extent is in 2015 (and 2014 too) much less than in 2013. Currently I do not include it in the total extent, its contribution would be about 120k max in 2013.


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Re: Home brew AMSR2 extent & area calculation
« Reply #1442 on: March 07, 2015, 06:11:15 PM »
@wipneus: the Baltic saw its record low in winter 2007-2008 with just 49,000 km2. From what I can see that is still more than the current situation, but I can't find any numbers for this winter (anyone?). It's only observation.

The average winter ice extent is 204,000 km2, from a total of 420,000 km2 that the Baltic is.

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Re: Home brew AMSR2 extent & area calculation
« Reply #1443 on: March 07, 2015, 06:51:36 PM »
@wipneus: the Baltic saw its record low in winter 2007-2008 with just 49,000 km2. From what I can see that is still more than the current situation, but I can't find any numbers for this winter (anyone?). It's only observation.

The average winter ice extent is 204,000 km2, from a total of 420,000 km2 that the Baltic is.

Hi majava,

From the sea ice concentration product that is used in this thread, Uni Hamburgs ASI AMSR2 3.125km product, I measure currently 10.7k extent and 7.9k area.

The numbers that you are referring to are probably based on the NSIDC NASA Team sea ice concentration. Using that I get 69.4k for extent and 24.4k for area.

NSIDC has a hard time measuring accurately here, with such a big coast/area ratio. I think the UH AMSR2 based data is the more accurate one.

My data you can find here:

https://sites.google.com/site/arctischepinguin/home/sea-ice-extent-area/data

the relevant files are:

nsidc_nt_nrt_detail.txt and nsidc_nt_final_detail.txt.gz for NSIDC based
uh_am2_arc.txt for the UH AMSR2 based one.

balt.e and balt.a are the columns to use.

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Re: Home brew AMSR2 extent & area calculation
« Reply #1444 on: March 07, 2015, 07:01:16 PM »
thanks, wipneus! 8)

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Re: Home brew AMSR2 extent & area calculation
« Reply #1445 on: March 11, 2015, 11:01:35 AM »
Winds are blowing into the Arctic from Siberia again, like it did most of the past winter facilitating ice growth. Now with somewhat milder temps, refreezing may not happen so quick. A crack has opened from Laptev tot the East Siberian Sea separating the land fast ice from the pack.

(click to animate)

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Re: Home brew AMSR2 extent & area calculation
« Reply #1446 on: March 11, 2015, 11:09:58 AM »
it is just me or is the ice pack more mobile than usual for this time of year?

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Re: Home brew AMSR2 extent & area calculation
« Reply #1447 on: March 11, 2015, 11:44:13 AM »
The ice in the pack appears to me just as mobile as the last two years, although it is rather compact. The amount of land fast ice is less than in 2014 especially in the ESS.

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Re: Home brew AMSR2 extent & area calculation
« Reply #1448 on: March 11, 2015, 11:54:39 AM »
It is not an  illusion. Heard an illustration that would fit. If you have a room stuff with popcorn and blow a fan it will hardly move. Empty half way and it will bounce around a lot. Not only is the area getting small the ice is getting more and more broken up into smaller pieces. It also is getting lighter because it is a lot thinner (although you do come across compacted ice over 30m thick more like icebergs) and because it is becoming young it is more saline therefore rides higher. All this means that the ice gets pushed around more and more.
Added to it is that because you have more open water that is becoming warmer you are getting far more storms that are becoming far stronger.
In other years because of the direction storms have taken the ice has stayed more in the Arctic. This year since Jan it seems that every storm has been pushing the ice out of the Arctic and therefore you are seeing much more evidence of how fast that ice can move now.
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Re: Home brew AMSR2 extent & area calculation
« Reply #1449 on: March 11, 2015, 02:52:11 PM »
Winds are blowing into the Arctic from Siberia again, like it did most of the past winter facilitating ice growth. Now with somewhat milder temps, refreezing may not happen so quick. A crack has opened from Laptev tot the East Siberian Sea separating the land fast ice from the pack.

(click to animate)
A quick visit to climate Reanalizer reveals that airflow is just below or close zero C. No more refreeze, I think.
This space for Rent.