Home brew AMSR2 extent & area calculation

[Wipneus]

Since the last time I showed an animation of the Canadian Archipelago the ice in the Parry Channel has become mobile. As some of it is moving into (and clogging) the southern channels) open water is appearing. Interestingly (and different from last year) is that no ice is is replenished from the northern channels: most of that ice looks still frozen stiff but breakdown is in progress there as well.
Nares transport is absent as well due to unfavorable winds.

[Wipneus]

Update 20140827.

Extent: -0k8 (-15k vs 2013, +1366k vs 2012)
Area: -26k3 (+26k vs 2013, +1268k vs 2012)

The totals made only small changes, but regionally they are a bit bigger. The CAB and the ESS make the largest changes:  CAB declines especially in area (-61k) but ESS increases also especially in area (+28k).
 
You will find the updated graphs in the top post

The details (in 1000 km²):


Extent:
   Central Arctic Basin       East Siberian Sea              Laptev Sea
                  -15.0                    15.1                    -0.3
               Kara Sea             Barents Sea           Greenland Sea
                   -6.6                    -0.1                     1.3
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -2.1                     0.0                     0.3
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                    7.3                    -0.4                    -0.1
             Bering Sea          Sea of Okhotsk            Total Extent
                   -0.1                     0.0                    -0.8

Area:
   Central Arctic Basin       East Siberian Sea              Laptev Sea
                  -60.8                    27.9                    -0.1
               Kara Sea             Barents Sea           Greenland Sea
                   -9.6                     8.4                     5.0
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -1.4                     0.0                     0.3
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   -4.5                     8.2                     0.6
             Bering Sea          Sea of Okhotsk              Total Area
                    0.0                     0.0                   -26.3

[Wipneus]

Selecting a region of the day to highlight often starts with looking at the wind map of earth.nullschool.net and look at interesting winds, strong an preferably from the lower latitudes.
Today the southerly winds over Chukchi hit the ice pack at the Beaufort border enlarging the open water there. At the same time in the north and the west of Chukchi the winds are weak from the north but the effect of growing ice extent can be seen.

[Wipneus]

Update 20140828.

Extent: -29k9 (-2k vs 2013, +1416k vs 2012)
Area: -18k1 (+45k vs 2013, +1329k vs 2012)

There seems to be a race going where 2013 and 2014 have been so close together for the last few weeks that any of the years may "win", whatever that means.  Today Kara declines both in extent and area, yet the NE passages (including the one around Severnaya Zemlya) have blocked further. The CAB saw a big increase in area, while the ESS declined significantly.
 
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                     0.5                    -0.1
               Kara Sea             Barents Sea           Greenland Sea
                  -12.5                    -1.2                    -7.6
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                    0.2                     0.0                     0.0
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   -6.8                    -3.1                     0.3
             Bering Sea          Sea of Okhotsk            Total Extent
                    0.0                     0.0                   -29.9

Area:
   Central Arctic Basin       East Siberian Sea              Laptev Sea
                   32.1                   -19.7                    -0.1
               Kara Sea             Barents Sea           Greenland Sea
                  -11.7                     0.3                    -9.1
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                    0.0                     0.0                     0.5
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   -5.9                    -3.2                    -1.3
             Bering Sea          Sea of Okhotsk              Total Area
                    0.0                     0.0                   -18.1

[Wipneus]

Region of the day is the East Siberian Sea. Ice is moving with the western winds, but taht has little or no effect on the total extent.

[Wipneus]

Update 20140829.

Extent: -42k2 (+1k vs 2013, NAk vs 2012)
Area: -11k7 (-56k vs 2013, NAk vs 2012)

Area and extent declines today in CAA, Greenland and Barents Sea. The area increased in the ESS and the CAB.
 
You will find the updated graphs in the top post

The details (in 1000 km²):


Extent:
   Central Arctic Basin       East Siberian Sea              Laptev Sea
                    2.9                     4.0                    -1.2
               Kara Sea             Barents Sea           Greenland Sea
                   -1.1                   -10.7                   -16.4
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                    0.7                     0.0                     0.7
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                  -20.0                     0.0                    -1.1
             Bering Sea          Sea of Okhotsk            Total Extent
                    0.0                     0.0                   -42.2

Area:
   Central Arctic Basin       East Siberian Sea              Laptev Sea
                   15.3                    20.6                    -0.9
               Kara Sea             Barents Sea           Greenland Sea
                    1.4                   -15.9                   -15.2
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                    0.4                     0.0                     0.6
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                  -15.5                    -2.0                    -0.4
             Bering Sea          Sea of Okhotsk              Total Area
                    0.0                     0.0                   -11.7

[Wipneus]

Image of the day is the Canadian Archipelago. Over the Parry Channel the winds are south, narrowing the open water there. The reverse is true in the south, in the south the open water gets a bit bigger. There is a lot of "reds": disappearing false coastal ice visible, note that this is mostly filtered in my calculations and should not affect the area and extent numbers too much.

[gciriani]

Hello Wipneus,
What's the difference between your calculated daily change and the one coming from IJIS/JAXA? I understand that you use the same sensor, so I thought the numbers should be the same, or correlate in some shape and form. For today, Espen reports "down 25,829 km2 from previous you report", while you report -42k2.

[Wipneus]

Hello Wipneus,
What's the difference between your calculated daily change and the one coming from IJIS/JAXA? I understand that you use the same sensor, so I thought the numbers should be the same, or correlate in some shape and form. For today, Espen reports "down 25,829 km2 from previous you report", while you report -42k2.

gciriani,

I am using sea ice concentration data as calculated by the University of Hamburg. They use the microwave brightness data measured by the AMSR2 instrument on the GCOM-W satellite.

IJIS/Jaxa retrieves data from the same AMSR2 instrument, but uses other microwave bands (frequencies) and other algorithms (the calculations differ). Also the resolution differ: 3.125 km for the Uni Hamburg data, 10 km for the Jaxa data which has some influence particularly in extent.

Jaxa also produces sea ice concentration data, from which I calculate extent and area. I don't publish this data, but the results are included in the daily updated graphs in the top post.

Here I show area and extent. As you can see area from UH data and that of Jaxa track each other quite well, but there are interesting (unexplained) short time differences. Extent from UH data is consistently below the extent calculated from Jaxa data. Main reason is probably the difference in resolution.

[Wipneus]

Update 20140830.

Extent: -43k1 (-15k vs 2013, +1322k vs 2012)
Area: -77k0 (-176k vs 2013, +1201k vs 2012)

Extent and area totals are now both below 2013. Area is declining most, CAB is biggest as usual but with help from CAA and the ESS.  Extent changes are smaller, the CAA and CAB decline most.
 
You will find the updated graphs in the top post

The details (in 1000 km²):


Extent:
   Central Arctic Basin       East Siberian Sea              Laptev Sea
                  -13.3                     6.9                     0.0
               Kara Sea             Barents Sea           Greenland Sea
                    3.6                    -2.2                   -11.6
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                    1.1                     0.0                     0.6
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                  -19.4                    -8.3                    -0.4
             Bering Sea          Sea of Okhotsk            Total Extent
                    0.0                     0.0                   -43.1

Area:
   Central Arctic Basin       East Siberian Sea              Laptev Sea
                  -36.8                   -10.7                    -0.1
               Kara Sea             Barents Sea           Greenland Sea
                    2.5                    -1.7                    -8.2
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                    1.0                     0.0                     0.5
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                  -12.8                   -10.9                     0.1
             Bering Sea          Sea of Okhotsk              Total Area
                    0.0                     0.0                   -77.0

[Wipneus]

Here is the Beaufort region. The open water (that is partly over Chukchi and CAB) keeps expanding with now two cyclones over the section.

[Wipneus]

Continues from my previous post:

The area drop is even more remarkable considering the distance to the 2013 minima:

area 20140830  area 20130909 

4.291292           4.250043

So only 41k to go to "win" the race with 2013, could be realized tomorrow.


The extent numbers are:

extent 20140830  extent 20130909

4.857811               4.62149

Stilll 236k to go, that race is still open.

[gciriani]

As you can see area from UH data and that of Jaxa track each other quite well, but there are interesting (unexplained) short time differences. Extent from UH data is consistently below the extent calculated from Jaxa data.

Thanks Wipneus for the explanation to a newbie like me. It helps a lot! I'm interested in calculating the correlation between your (Uni Hamburg) daily total Extent change and JAXA's Extent daily change. Is it possible to get your numbers for the past several months in a file somewhere, rather than reading them from each individual post? Thanks for your time.

[Jim Hunt]

Is it possible to get your numbers for the past several months in a file somewhere, rather than reading them from each individual post? Thanks for your time.

Take a look at: https://sites.google.com/site/arctischepinguin/home/amsr2/data

[gciriani]

Take a look at: https://sites.google.com/site/arctischepinguin/home/amsr2/data

Thanks. I haven't used this data base yet, but only ran a correlation between Wipneus August numbers and JAXA. I obtain the best correlation when I correlate Wipneus changes with JAXA changes 4 days ahead. It may be a coincidence, because if one hunts for something one finds correlation even by pure chance where there is none. However, I thought it's interesting enough. Part of it is the delay introduced by the two-day average of JAXA. But there may be a physical explanation also in the way ice breaks up and expands from 3.125 km sectors to 10 km sectors. See graph attached.

[Wipneus]

Update 20140831.

Extent: -1.4 (-13k vs 2013, +1288k vs 2012)
Area: -23.1 (-190k vs 2013, +1218k vs 2012)

No "winner" yet: total area is now 4.268 Mm², about 18k above the 2013 minimum.
Total extent changed little, a drop in the CAB is compensated by an increase in the ESS.
 Same with area, but there the decline in the CAB is much bigger.

 
You will find the updated graphs in the top post

The details (in 1000 km²):


Extent:
   Central Arctic Basin       East Siberian Sea              Laptev Sea
                  -12.7                    19.6                     0.1
               Kara Sea             Barents Sea           Greenland Sea
                   -6.7                     0.5                     2.3
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                    0.3                     0.0                    -2.0
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   -3.1                     1.3                    -1.0
             Bering Sea          Sea of Okhotsk            Total Extent
                    0.0                     0.0                    -1.4

Area:
   Central Arctic Basin       East Siberian Sea              Laptev Sea
                  -34.3                    20.5                    -0.1
               Kara Sea             Barents Sea           Greenland Sea
                   -5.0                    -2.1                     2.3
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                    0.2                     0.0                    -1.6
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   -2.9                     0.4                    -0.5
             Bering Sea          Sea of Okhotsk              Total Area
                    0.0                     0.0                   -23.1

[Wipneus]

Region of the day is Kara. Almost all melted out by now, the little ice there is makes the NE Passage (proper by Vilkitsky Stratit) difficult (my assumption).

[Wipneus]

Take a look at: https://sites.google.com/site/arctischepinguin/home/amsr2/data

Thanks. I haven't used this data base yet, but only ran a correlation between Wipneus August numbers and JAXA. I obtain the best correlation when I correlate Wipneus changes with JAXA changes 4 days ahead. It may be a coincidence, because if one hunts for something one finds correlation even by pure chance where there is none. However, I thought it's interesting enough. Part of it is the delay introduced by the two-day average of JAXA. But there may be a physical explanation also in the way ice breaks up and expands from 3.125 km sectors to 10 km sectors. See graph attached.

gciriani, here is the cross-correlation function (as calculated by the ccf() function in R) between changes in IJIS extent and my Uni Hamburg extent. Maximum correlation is a lag of zero, so my conclusion was/is that the real lag is less than a day.

[gciriani]

... the cross-correlation function (as calculated by the ccf() function in R) between changes in IJIS extent and my Uni Hamburg extent. Maximum correlation is a lag of zero, so my conclusion was/is that the real lag is less than a day.

Wipneus, thanks for the graph. Yes, indeed. I ran the numbers for the past (almost) full year (20130916-20140830) and the correlation is highest for zero days lag. However, if done for the latest month (August), for some reason it's highest for 3 days. It might be a statistical fluke.

[iceman]

Region of the day is Kara. Almost all melted out by now, the little ice there is makes the NE Passage (proper by Vilkitsky Stratit) difficult (my assumption).

Looks like with a fairly high pressure gradient over the next two days, easterly winds will blow the remaining ice clear of the strait.
      The same winds will narrow, and then perhaps close, the gap of open water north and east of Severnaya Zemlya.  I hadn't expected it to stay open this long.

[Wipneus]

Update 20140901.

Extent: -0k9 (-6k vs 2013, +1384k vs 2012)
Area: -8k7 (-184k vs 2013, +1268k vs 2012)

Area is now 4.2594 Mm², only 9k4 above the 2013 minimum.

Total area and extent declines are small, regionally the CAB goes down and the ESS up, changes elsewhere are small.
 
You will find the updated graphs in the top post

The details (in 1000 km²):


Extent:
   Central Arctic Basin       East Siberian Sea              Laptev Sea
                  -13.0                    13.9                     0.1
               Kara Sea             Barents Sea           Greenland Sea
                    1.6                     0.9                     8.8
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -1.6                     0.0                    -1.0
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                    4.9                   -13.6                    -2.0
             Bering Sea          Sea of Okhotsk            Total Extent
                    0.0                     0.0                    -0.9

Area:
   Central Arctic Basin       East Siberian Sea              Laptev Sea
                  -22.1                    18.2                     0.0
               Kara Sea             Barents Sea           Greenland Sea
                   -2.1                    -0.8                     6.0
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -1.1                     0.0                    -0.8
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                    3.6                    -8.9                    -0.9
             Bering Sea          Sea of Okhotsk              Total Area
                    0.0                     0.0                    -8.7

[Wipneus]

The Laptev open water has not grown much over the past few days, actually it shrank. The unfavorable winds are likely the main cause.

[Wipneus]

It is high time for an update of the Fram Strait animation. As you can see there is little or no export, neither the Fram or the Victoria Channel.

(needs a click to animate)

[Wipneus]

For fun: this is 2013:

[gciriani]

Update 20140901.
...
You will find the updated graphs in the top post...

Wipneus, or whoever is knowledgeable: the top post shows JAXA data for the individual regions. Where is it possible to find JAXA's individual regions' numbers please?

[Wipneus]

Update 20140901.
...
You will find the updated graphs in the top post...

Wipneus, or whoever is knowledgeable: the top post shows JAXA data for the individual regions. Where is it possible to find JAXA's individual regions' numbers please?

Not anything in near real time. I will put my calculations up some time this week.

BTW, my input data come directly from Jaxa servers. There are differences with IJIS/Jaxa extent.

[Bruce]

It is high time for an update of the Fram Strait animation. As you can see there is little or no export, neither the Fram or the Victoria Channel.

Seems like a fair bit through the Victoria. It backs up and changes direction at some point, but the beginning and end of the animation show pretty strong flow.

The Fram, on the other hand, seems like it has been pretty dead for most of the summer. Probably plays some part in this year's relatively high extent.

[Sonia]

It is high time for an update of the Fram Strait animation. ...

This animation nicely shows a rather large ice floe passing through the Victoria, just off Franz Josef Land.  This floe has taken much of the summer to edge closer and finally pass through the channel.  It has stayed mostly intact up until now, but today's MODIS images are hinting that it might be breaking up.  I expect it to go "poof" soon.

[Wipneus]

Update 20140902.

Extent: +3k8 (+33k vs 2013, +1495k vs 2012)
Area: -22k6 (-189k vs 2013, +1313k vs 2012)

It is final, area is now 4.237 Mm², "beating" the 2013 minimum (reached on 20130909) by -13k.

Extent is not that far, upticks in CAA and Greenland Sea caused a small increase in total extent. By area the CAB and ESS still throw in enough declines to go below that minimum.
 
You will find the updated graphs in the top post

The details (in 1000 km²):


Extent:
   Central Arctic Basin       East Siberian Sea              Laptev Sea
                   -6.8                    -9.5                     0.4
               Kara Sea             Barents Sea           Greenland Sea
                    0.2                     2.2                    13.9
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -0.1                     0.0                     0.1
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                    8.2                    -2.9                    -1.7
             Bering Sea          Sea of Okhotsk            Total Extent
                    0.0                     0.0                     3.8

Area:
   Central Arctic Basin       East Siberian Sea              Laptev Sea
                  -17.7                   -29.2                     0.7
               Kara Sea             Barents Sea           Greenland Sea
                    1.3                    -3.8                    16.9
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                    0.1                     0.0                     0.1
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   11.1                    -1.1                    -0.9
             Bering Sea          Sea of Okhotsk              Total Area
                    0.0                     0.0                   -22.6

[Wipneus]

A fairly big cyclone is stirring up the Chukchi Sea.

[Wipneus]

Update 20140903.

Extent: -4k5 (+68k vs 2013, +1525k vs 2012)
Area: -20k9 (-181k vs 2013, +1338k vs 2012)

Total extent change is small, the decline in the CAB is offset by an increase in the CAA. Total area change is mostly caused by a decline in the CAB.
 
You will find the updated graphs in the top post

The details (in 1000 km²):


Extent:
   Central Arctic Basin       East Siberian Sea              Laptev Sea
                  -23.4                    -7.7                     0.1
               Kara Sea             Barents Sea           Greenland Sea
                   -0.3                     4.1                     5.6
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                    1.4                     0.0                    -0.2
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   21.2                    -5.7                     0.2
             Bering Sea          Sea of Okhotsk            Total Extent
                    0.0                     0.0                    -4.5

Area:
   Central Arctic Basin       East Siberian Sea              Laptev Sea
                  -36.1                     3.9                     0.2
               Kara Sea             Barents Sea           Greenland Sea
                    4.3                     6.6                    -1.2
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                    1.0                     0.0                    -0.1
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                    8.8                    -8.6                     0.2
             Bering Sea          Sea of Okhotsk              Total Area
                    0.0                     0.0                   -20.9

[Wipneus]

The ESS changes today are small, but the as the hi-res AMSR2 image shows there is lot of change on the small scale.

[gciriani]

...where is it possible to find JAXA's individual regions' numbers please?

...I will put my calculations up some time this week.
... There are differences with IJIS/Jaxa extent.

I'm also dying to see the chart for 2013, comparing regional extent of UH vs JAXA. Is there an archive at ArctischePenguin? I noticed an interesting behavior in how JAXA extent changes follow UH extent changes, and I wanted to see if this happened last year too.

[Wipneus]

Update 20140904.

Extent: -40.2 (+53k vs 2013, +1492k vs 2012)
Area: -39.2 (-236k vs 2013, +1304k vs 2012)

Area is now -73k compared with the 2013 minimum on 20130909.
Extent is 4.81456 Mm², still +193k from the 2013 minimum (4.62149 Mm² on 20130909)

Today's totasl area decline is dominated by the CAA, while smaller extent drops in Kara, CAB and CAA make a very similar total in extent change.
 
You will find the updated graphs in the top post

The details (in 1000 km²):


Extent:
   Central Arctic Basin       East Siberian Sea              Laptev Sea
                  -11.1                    -2.0                    -0.5
               Kara Sea             Barents Sea           Greenland Sea
                  -13.9                     0.2                    -7.3
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                    0.4                     0.0                     0.0
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   -9.6                     4.1                    -0.5
             Bering Sea          Sea of Okhotsk            Total Extent
                    0.0                     0.0                   -40.2

Area:
   Central Arctic Basin       East Siberian Sea              Laptev Sea
                   -2.6                    -2.8                    -0.4
               Kara Sea             Barents Sea           Greenland Sea
                   -9.9                     4.5                    -5.9
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                    0.1                     0.0                     0.0
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                  -27.3                     5.5                    -0.3
             Bering Sea          Sea of Okhotsk              Total Area
                    0.0                     0.0                   -39.2

[Wipneus]

A cyclone over the north of the Canadian Archipelago is trying to mobilize the ice there and gives the ice in the Parry Channel a heavy beating. The crack between the Central Basin and the "channel ice" has opened again.

[Wipneus]

An animation shows that the ice in the northern channels is still solid, thus preventing ice from the central pack filling the Parry Channel.

[Wipneus]

Update 20140901.
...
You will find the updated graphs in the top post...

Wipneus, or whoever is knowledgeable: the top post shows JAXA data for the individual regions. Where is it possible to find JAXA's individual regions' numbers please?

Not anything in near real time. I will put my calculations up some time this week.

BTW, my input data come directly from Jaxa servers. There are differences with IJIS/Jaxa extent.

I upload my Jaxa calculations now to the same place ( https://sites.google.com/site/arctischepinguin/home/amsr2/data ) as above.

[gciriani]

I upload my Jaxa calculations now to the same place ( https://sites.google.com/site/arctischepinguin/home/amsr2/data ) as above.

Thanks Wipneus! I thought I didn't need further explanation, but I do. From previous posts, I thought IJIS numbers, those downloaded from UAF.edu were an average of the last two days, and that your numbers were the daily numbers without averaging. However, I see that total extent for the last two days 9/2-3 in your txt file are 5.196482 + 5.160827, which averages to 5.178655; but the IJIS number for 9/3 is 5179456, which is 801 km2 above. Could you please clarify?

[crandles]

I think the 15% test is applied to all data in a 48 hour period.

(Not 15% test for 24 hours period to arrive at daily number then average two daily numbers.)

[gciriani]

I think the 15% test is applied to all data in a 48 hour period.

Oh, I see. Do you know if the 15% is performed on the average of the 48-hour period, or if it is an inclusive OR, an AND or some other combination?

[crandles]

I think the 15% test is applied to all data in a 48 hour period.

Oh, I see. Do you know if the 15% is performed on the average of the 48-hour period, or if it is an inclusive OR, an AND or some other combination?

Not sure I understand the question so I probably don't know. AFAICS whether you perform 15% on total of several observations over 48 hours or on average of those observations doesn't make any difference. I think it is one 15% test on all the observations in a 48 hour period rather than one test on 1st 24 hour period and 1 test on last 24 hour period.

I believe the monthly NSIDC average works by testing whether there is coverage of 15% of all the observations in the month.
i.e just one 15% test on sum/average of all the observations in the month (not daily 15% tests).

I don't see any logic in "an inclusive OR, an AND or some other combination". But maybe I am just not following.

[Wipneus]

Update 20140905.

Extent: -65k9 (+4k vs 2013, +1426k vs 2012)
Area: +28k9 (-181k vs 2013, +1290k vs 2012)

A relatively big decline in extent, most in the CAB, ESS and CAA. The same CAB, drives the uptick in area, in spite of the decline in the ESS.
 
You will find the updated graphs in the top post

The details (in 1000 km²):


Extent:
   Central Arctic Basin       East Siberian Sea              Laptev Sea
                  -19.4                   -21.0                    -0.3
               Kara Sea             Barents Sea           Greenland Sea
                   -6.1                    -3.2                     3.4
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -0.3                     0.0                     0.0
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                  -24.5                     5.8                    -0.3
             Bering Sea          Sea of Okhotsk            Total Extent
                    0.0                     0.0                   -65.9

Area:
   Central Arctic Basin       East Siberian Sea              Laptev Sea
                   45.2                   -23.4                    -0.2
               Kara Sea             Barents Sea           Greenland Sea
                   -5.0                    -1.4                     4.6
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                    0.0                     0.0                     0.0
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   -6.7                    15.9                    -0.2
             Bering Sea          Sea of Okhotsk              Total Area
                    0.0                     0.0                    28.9

[Wipneus]

The Arctic is full of larger and smaller cyclones. Two of the smaller one are visible in this image of the Greenland Sea, one north and one south of the Fram Strait.

[Wipneus]

I upload my Jaxa calculations now to the same place ( https://sites.google.com/site/arctischepinguin/home/amsr2/data ) as above.

Thanks Wipneus! I thought I didn't need further explanation, but I do. From previous posts, I thought IJIS numbers, those downloaded from UAF.edu were an average of the last two days, and that your numbers were the daily numbers without averaging. However, I see that total extent for the last two days 9/2-3 in your txt file are 5.196482 + 5.160827, which averages to 5.178655; but the IJIS number for 9/3 is 5179456, which is 801 km2 above. Could you please clarify?

gciriani, best that I can do explain what I calculate: download the L3 ice concentration data of the date from Jaxa and a straightforward calculation ( with a cut-off of 15%) of area and extent over the 14 well know regions. There is user documentation on the Jaxa site, but I haven't read anything about averaging. The results are exceptionally smooth though, so perhaps...

The IJIS Jaxa calculation does differ, but hardly any details. I don't know if they are using the same L3 data, don't know about what is included ( I suspect everything including lake ice), don't know if there is additional filtering.

It looks like there is a 12 hour difference between the two (using the cross correlation function as before).

[Wipneus]

Update 20140906.

Extent: -61k2 (-31k vs 2013, +1430k vs 2012)
Area: -80k2 (-245k vs 2013, +1185k vs 2012)

Extent is now 4.6874 Mm², about 65k above the 2013 minimum (reached on 20130909).

Big drops both in extent and area, no doubt due to the presence of a number of cyclones with large wind fields. Continental air is blown in over the ESS that takes the largest hit, with the adjacent sector of the CAB.
 
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                   -39.7                    -0.1
               Kara Sea             Barents Sea           Greenland Sea
                   -5.5                     4.5                     2.1
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                    1.9                     0.0                     0.0
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                  -12.3                     2.0                    -0.2
             Bering Sea          Sea of Okhotsk            Total Extent
                    0.0                     0.0                   -61.2

Area:
   Central Arctic Basin       East Siberian Sea              Laptev Sea
                  -32.2                   -22.8                    -0.3
               Kara Sea             Barents Sea           Greenland Sea
                   -2.0                     7.8                    -2.6
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                    1.0                     0.0                     0.0
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                  -13.0                   -16.0                     0.0
             Bering Sea          Sea of Okhotsk              Total Area
                    0.0                     0.0                   -80.2

[Wipneus]

The East Siberian Sea Section is where most of the melt is.

[Wipneus]

In this 14 day animation the advection causing increase of ESS ice cover followed by a period of decrease can be seen. Melting takes place over the whole period.

[Wipneus]

Update 20140907.

Extent: +24.3 (+18k vs 2013, +1451k vs 2012)
Area: +117.4 (-102k vs 2013, +1339k vs 2012)

Increases, especially area, may make an end to an end of season spurt. Extent has not been below the 2013 minimum yet and is currently about +90k above.
Regionally it is the CAB and ESS ice that grows, the same regions that caused the decline of the last few 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
                   20.1                    15.7                    -1.0
               Kara Sea             Barents Sea           Greenland Sea
                   -3.5                     5.5                   -10.0
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -0.6                     0.0                     0.0
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   -3.4                     1.9                    -0.5
             Bering Sea          Sea of Okhotsk            Total Extent
                    0.0                     0.0                    24.3

Area:
   Central Arctic Basin       East Siberian Sea              Laptev Sea
                   81.2                    32.2                    -0.5
               Kara Sea             Barents Sea           Greenland Sea
                   -1.8                     6.4                    -6.4
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -1.2                     0.0                     0.0
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   -0.5                     8.1                    -0.2
             Bering Sea          Sea of Okhotsk              Total Area
                    0.0                     0.0                   117.4

[Wipneus]

The Laptev open water, aka "Laptev Bite", did shrink a bit today. It is all winds and currents of course.

[Lord M Vader]

Wipneus: how close are we to see the Northwest Passage (Amundsens Route) open up temporarily this year? Looks like there still is a small possibilty for the ice to open up given its appearance on Hamburg charts..  Or maybe not...

Another thing I'm wondering about is how the ice west of Severanya Zemlya will act now when it finally has been separated from land area...

Another thing that is interesting is how the ice around Svalbard and Frans Josefs land will behave if the strong cyclones forecasted to come in about 5-7 days... (According to 12 z EURO)

Viddaloo: here is the link: http://old.ecmwf.int/products/forecasts/d/charts/medium/deterministic