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plinius

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Re: Home brew AMSR2 extent & area calculation
« Reply #1700 on: July 13, 2015, 04:33:50 PM »
Looks like it, though the region was anyway melting out:
http://ocean.dmi.dk/satellite/index.uk.php

See the temperatures over the past 3 days...


jdallen

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Re: Home brew AMSR2 extent & area calculation
« Reply #1701 on: July 13, 2015, 04:49:27 PM »
New siberian islands produce a general weakness in the ice, which usually propagates towards the  pole by the transarctic current. Depends a bit on the weather if and where it forms, but suppose it is mainly in years with strong transarctic drift during late winter/spring, and then the right wind patterns later on.
See e.g. here:
http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/ARCHIVE/20050824.jpg
It's optimal melting conditions for sure, combined with some drift; modest surface winds have been shoving the pack from the Northern Laptev towards exits to the Kara and Barents around Franz Josef and to a lesser degree towards the Fram
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Re: Home brew AMSR2 extent & area calculation
« Reply #1702 on: July 14, 2015, 08:24:21 AM »
The arch in the Nares Strait is caving in. This actually the Baffin Bay region, so when the export train starts running this will delay the already slow regional decline even more.

plinius

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Re: Home brew AMSR2 extent & area calculation
« Reply #1703 on: July 14, 2015, 12:59:56 PM »
It's optimal melting conditions for sure, combined with some drift; modest surface winds have been shoving the pack from the Northern Laptev towards exits to the Kara and Barents around Franz Josef and to a lesser degree towards the Fram

Fully agreed, but the main question was why this position is open frequently. Wind pattern/drift certainly plays a role, but after all the fact that it happens downwind from the New Siberian islands, which produce a trough in the ice thickness north of them if the transarctic drift is on, should not be neglected.

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Re: Home brew AMSR2 extent & area calculation
« Reply #1704 on: July 14, 2015, 10:36:54 PM »
New siberian islands produce a general weakness in the ice, which usually propagates towards the  pole by the transarctic current. Depends a bit on the weather if and where it forms, but suppose it is mainly in years with strong transarctic drift during late winter/spring, and then the right wind patterns later on.
See e.g. here:
http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/ARCHIVE/20050824.jpg
Maybe tidal flows?

plinius

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Re: Home brew AMSR2 extent & area calculation
« Reply #1705 on: July 14, 2015, 11:41:16 PM »
find that rather unlikely, because they should (if at all, I suspect it's marginal) lead to a compaction, though reduced rigidity may be a nice point. I thought more of a sea-side polynya/thinned zone, which is supported by the drift of the Siberian coast downstream of the East Siberian islands, which cannot "heal" in late winter.
Watch it open this February/March:
http://www7320.nrlssc.navy.mil/hycomARC/navo/arcticictn_nowcast_anim365d.gif


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Re: Home brew AMSR2 extent & area calculation
« Reply #1706 on: July 15, 2015, 02:53:55 PM »
The arch in the Nares Strait is caving in. This actually the Baffin Bay region, so when the export train starts running this will delay the already slow regional decline even more.

It is amazing to see how quickly the ice at the northern entrance to the strait reacts to the collapse of the arch.

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Re: Home brew AMSR2 extent & area calculation
« Reply #1707 on: July 16, 2015, 10:15:31 AM »
Update 20150715.
Changes from 20150708.

Extent: -710.6 (+316k vs 2014, +400k vs 2013, +693k vs 2012)
Area: -613.0 (-98k vs 2014, +87k vs 2013, +365k vs 2012)

The strong declines this week, about -100k/day for total extent slightly less for area, are similar to the past few years. The relative large amount of remaining ice in the Hudson and Baffin are not giving those numbers the expected boost yet. Considering all regions expect Hudson and Baffing makes 2015 approximately track 2013. Considering just the restricted Basin (CAB+Beaufort to Laptev) makes 2015 still staying quite close to 2012. Remember the new Basin-only graphs announced here.

Looking at the other regions, ESS and Laptev are loosing ice cover fast. The CAB does not show much extent decline, no big polynya, no regional "bites" yet.
Despite somewhat cooler temperatures, dropping below zero occasionally, total area in melting ( as shown in the ADS-NIPR Jaxa thickness/melting maps) increased. The same is true for the melting percentage, especially the Beaufort region.
Taken with the uncertainty in thickness, lack of ice export and mixed signals in the melting conditions I find it hard to predict what is to happen. Staying with 2012 will require at least a repeat of that exceptional melting season deep into August.
 
You will find the updated graphs in the top post

The details (in 1000 km2):


Extent:
   Central Arctic Basin       East Siberian Sea              Laptev Sea
                  -15.3                  -163.0                  -136.3
               Kara Sea             Barents Sea           Greenland Sea
                  -28.7                    -9.1                   -57.3
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                  -76.7                    -0.2                  -105.6
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                  -62.5                   -23.3                   -31.7
             Bering Sea          Sea of Okhotsk            Total Extent
                   -1.2                     0.1                  -710.6

Area:
   Central Arctic Basin       East Siberian Sea              Laptev Sea
                   68.0                  -161.8                  -133.2
               Kara Sea             Barents Sea           Greenland Sea
                  -26.2                    -8.2                   -47.1
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                  -67.1                    -0.1                  -128.5
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                  -73.7                   -22.8                   -11.3
             Bering Sea          Sea of Okhotsk              Total Area
                   -1.0                     0.1                  -613.0

Wipneus

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Re: Home brew AMSR2 extent & area calculation
« Reply #1708 on: July 16, 2015, 10:37:57 AM »
In this sequence of the Beaufort and Chukchi regions, some developing polynya can be observed. Some of the larger floes that venture into te open water beyond the ice edge can be seen melting (and some smaller ones going poof). On the side of Chukchi the ice looks mushy, in 250m res MODIS it shows that the size of the floes are just much smaller.

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Re: Home brew AMSR2 extent & area calculation
« Reply #1709 on: July 17, 2015, 08:02:31 AM »
Solid declines today (seen also by Jaxa). Some of it is caused by the late melting in Hudson and Baffin, some of it the Kara Sea Ice. Here the NE passage has "opened". There will probably still some sub 15% ice, there remains enough ice to re-block the passage and the passage thought Laptev will still stay blocked for a while anyway.

slow wing

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Re: Home brew AMSR2 extent & area calculation
« Reply #1710 on: July 17, 2015, 11:56:19 AM »
These high resolution .gifs are superb, thanks Wipneus.


That ice in the Chukchi Sea looks on its last legs.

The ice in the Beaufort is still in larger chunks, but they  are small enough and with enough gaps that they will be continually swept over areas of open water and that can't be good for them!

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Re: Home brew AMSR2 extent & area calculation
« Reply #1711 on: July 18, 2015, 08:46:35 AM »
The Canadian Archipelago, compared with 2013. It seems the southern NW passage is as slow as the nearby Hudson and Baffin regions. Seen by the breakup of ice in the M'Clure Strait the main passage is well ahead.

jdallen

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Re: Home brew AMSR2 extent & area calculation
« Reply #1712 on: July 18, 2015, 09:02:41 AM »
The Canadian Archipelago, compared with 2013. It seems the southern NW passage is as slow as the nearby Hudson and Baffin regions. Seen by the breakup of ice in the M'Clure Strait the main passage is well ahead.
It's a lot more  broken up than appears at first glance, Wipneus:

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Re: Home brew AMSR2 extent & area calculation
« Reply #1713 on: July 18, 2015, 12:47:29 PM »
The Canadian Archipelago, compared with 2013. It seems the southern NW passage is as slow as the nearby Hudson and Baffin regions. Seen by the breakup of ice in the M'Clure Strait the main passage is well ahead.
It's a lot more  broken up than appears at first glance, Wipneus:

I'd say it is visibile enough, part of the main northern passage and quite early.

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Re: Home brew AMSR2 extent & area calculation
« Reply #1714 on: July 18, 2015, 01:15:24 PM »
As noticed before, here and elsewhere, there is an unusual amount of ice still present in the Hudson and Baffin Bay's. Some of it is disappearing  fast now (increasing the daily decline numbers).
It looks like some stubborn ice on the coasts of Baffin and in the Foxe Basin (north of the Hudson Bay) will hold out for a while.

I am experimenting with the colors in the daily delta map. There are pinkish and bluish colors added where concentration changes over 7%, positive or negative. Red and darker blue indicate where concentration crosses the 15% cut off.

iceman

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Re: Home brew AMSR2 extent & area calculation
« Reply #1715 on: July 18, 2015, 05:49:58 PM »
....  There will probably still some sub 15% ice, there remains enough ice to re-block the passage and the passage thought Laptev will still stay blocked for a while anyway.

A route through Laptev could open up earlier than expected, if the lobe of ice in the southern part of the sea gets cut off from the main pack. My guess is the Northwest Passage and Northern Sea Route will open within a few days of each other: late July and early August.

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Re: Home brew AMSR2 extent & area calculation
« Reply #1716 on: July 19, 2015, 03:27:48 AM »
The Canadian Archipelago, compared with 2013. It seems the southern NW passage is as slow as the nearby Hudson and Baffin regions. Seen by the breakup of ice in the M'Clure Strait the main passage is well ahead.

However, the area north of the CAA looks a lot worse in '15 than in '13.
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Re: Home brew AMSR2 extent & area calculation
« Reply #1717 on: July 21, 2015, 01:22:54 PM »
Hudson Bay Cliff:

jdallen

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Re: Home brew AMSR2 extent & area calculation
« Reply #1718 on: July 21, 2015, 05:51:38 PM »
Hudson Bay Cliff:
Wow! Very dramatic images, but no surprise at all here.
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Re: Home brew AMSR2 extent & area calculation
« Reply #1719 on: July 23, 2015, 08:57:02 AM »
Update 20150722.
Changes from 20150715.

Extent: -934.6 (-227k vs 2014, +50k vs 2013, +246k vs 2012)
Area: -883.8 (-429k vs 2014, -291k vs 2013, +99k vs 2012)

Strong declines amounting to about -130k/day for both total area and extent. All regions contribute, specially the Hudson and ESS. If there is one region that is slow it would be Baffin that has plenty of unusual ice for the date.

The numbers take 2015 well past 2014 that had turned to moderate melt rates for the rest of the season by this time. 2013 went shallow about this date so we will see about that next week.
Total extent is still above 2012, but no more than the excess ice extent in Baffin and Hudson. Leaving those out, with similar extents, total area is now lower than in 2012 by about -150k.

Melting area, as shown in the Jaxa AMSR2 thickness/melting maps, is still high, higher than 2014 but not much over 2013. The  2013 melting fell back quickly in the last week of July, so it will be interesting to see how long 2015 will hold.

Temperatures (ECMWF) were well above freezing over the Central Arctic, but dropping below zero more and more on the Pacific side. Until now I do not see much of that in the area figures.

2013 and 2014 will be most likely be beaten in the race for the lowest minimum. To stay in competition with 2012, 2015 will have to repeat some of the remarkable(!) persistence of 2012 the melt rates. How likely that is should become clear in the coming weeks.   
 
You will find the updated graphs in the top post

The details (in 1000 km2):


Extent:
   Central Arctic Basin       East Siberian Sea              Laptev Sea
                  -46.8                  -177.1                  -112.5
               Kara Sea             Barents Sea           Greenland Sea
                  -91.1                   -15.7                   -24.4
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                  -92.2                     0.1                  -212.0
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                  -77.7                   -45.7                   -40.1
             Bering Sea          Sea of Okhotsk            Total Extent
                    0.9                     0.0                  -934.6

Area:
   Central Arctic Basin       East Siberian Sea              Laptev Sea
                  -95.4                  -150.7                   -83.2
               Kara Sea             Barents Sea           Greenland Sea
                  -71.4                   -13.6                     2.3
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                  -89.0                     0.1                  -131.2
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                 -125.4                  -102.4                   -24.4
             Bering Sea          Sea of Okhotsk              Total Area
                    0.7                    -0.1                  -883.8

« Last Edit: July 23, 2015, 09:18:29 AM by Wipneus »

Wipneus

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Re: Home brew AMSR2 extent & area calculation
« Reply #1720 on: July 23, 2015, 09:14:37 AM »
Not much ice dares to enter the Fram Strait.

(it takes a click to start)

seaicesailor

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Re: Home brew AMSR2 extent & area calculation
« Reply #1721 on: July 23, 2015, 11:14:57 AM »
Wipneus, may I make a question about the Chukchi sea ice edge? Indeed, is that edge still within Chukchi sea or is it already part of the Arctic central basin? I see a lot of red in the edge retreat but it doesn't seem as large extent loss in the number for Chukchi sea.

Puzzling for me :)

Thank you.


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Re: Home brew AMSR2 extent & area calculation
« Reply #1722 on: July 23, 2015, 11:38:03 AM »
sailor, does it help if I show you the regions mask (coming from Cryosphere Today website) that I use?

Nick_Naylor

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Re: Home brew AMSR2 extent & area calculation
« Reply #1723 on: July 23, 2015, 12:34:32 PM »
Wipneus, do you have access to a numerical version of Cryosphere Today's mask? I have only been able to find an image file (and I have no idea how to translate that into numbers).

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Re: Home brew AMSR2 extent & area calculation
« Reply #1724 on: July 23, 2015, 12:37:50 PM »
Eyeballing, it looks like the small northernmost "red spots" near the Chukchi are inside the CAB but the main extent front is just at the boundary.
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Re: Home brew AMSR2 extent & area calculation
« Reply #1725 on: July 23, 2015, 12:46:26 PM »
Quote
Not much ice dares to enter the Fram Strait.

Looks as though the Pacific side of the Arctic is due to cool down in several days.  Will be interesting to see if winds and ocean currents can nudge some flow out the Fram Strait.  The sea surface temp is certainly warm enough to do some damage....



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Re: Home brew AMSR2 extent & area calculation
« Reply #1726 on: July 23, 2015, 12:53:03 PM »
Wipneus, do you have access to a numerical version of Cryosphere Today's mask? I have only been able to find an image file (and I have no idea how to translate that into numbers).

Nick, image files are numerical files and I use them as such. In the programming languages that I use (Python and R) you can just read such a file to get an array with data that can be used in calculations.

Very convenient for me: the files are small from the built-in lossless compression, just say "display" to the file to see if it is not upside down, you can edit them programmatically or with an image editor (the Gimp).

Nick_Naylor

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Re: Home brew AMSR2 extent & area calculation
« Reply #1727 on: July 23, 2015, 01:10:58 PM »
Thanks for the explanation. Looks like an excuse to pick up some Python or R skills.

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Re: Home brew AMSR2 extent & area calculation
« Reply #1728 on: July 23, 2015, 02:55:13 PM »
sailor, does it help if I show you the regions mask (coming from Cryosphere Today website) that I use?

yes thx

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Re: Home brew AMSR2 extent & area calculation
« Reply #1729 on: July 24, 2015, 09:43:14 AM »
This section of the Arctic - located over the  ESS and Laptev regions - is currently declining fastest (after Hudson hit bottom). Both melting and transport can be seen.  Some ice in the ESS is transported into Laptev, one explanation why the extent in the ESS is dropping twice as fast as in the Laptev region.

(click req'd to animate)

seaicesailor

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Re: Home brew AMSR2 extent & area calculation
« Reply #1730 on: July 24, 2015, 10:22:09 AM »
Eyeballing, it looks like the small northernmost "red spots" near the Chukchi are inside the CAB but the main extent front is just at the boundary.

I think so too

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Re: Home brew AMSR2 extent & area calculation
« Reply #1731 on: July 24, 2015, 12:41:56 PM »
This section of the Arctic - located over the  ESS and Laptev regions - is currently declining fastest ....


This is the first image I've seen that shows the Laptev Lobe is now fully detached.  Largest ice detachment in main basin since GAC 2012?

EDIT: I meant within the confines of the Arctic Ocean, not the CAB proper.
« Last Edit: July 24, 2015, 03:10:59 PM by iceman »

seaicesailor

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Re: Home brew AMSR2 extent & area calculation
« Reply #1732 on: July 24, 2015, 01:28:25 PM »
This section of the Arctic - located over the  ESS and Laptev regions - is currently declining fastest ....


This is the first image I've seen that shows the Laptev Lobe is now fully detached.  Largest ice detachment in main basin since GAC 2012?

And the Northern route is unofficially open

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Re: Home brew AMSR2 extent & area calculation
« Reply #1733 on: July 24, 2015, 01:49:48 PM »
These .gifs are great, thanks Wipneus!

I hadn't appreciated how much processing is required until I started looking at EOSDIS and saw how much of the ice view is typically blocked by clouds.

This one of perhaps the most active region is particularly interesting viewing.

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Re: Home brew AMSR2 extent & area calculation
« Reply #1734 on: July 24, 2015, 03:50:22 PM »
   ....
And the Northern route is unofficially open

This coming week it will be a close call whether the passage remains open between Severnaya Zemlya and the Taymyr Peninsula.  Winds are blowing ice from western Laptev into the open water there, but above-normal temps will melt some of it.
    Maybe a few bunker-fuel burning ships will thread the gap in the meantime.

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Re: Home brew AMSR2 extent & area calculation
« Reply #1735 on: July 24, 2015, 06:38:47 PM »
On the latest map there is still some low concentration ice blocking the passage. I think you should wait for a path with zero ice before calling it open.

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Re: Home brew AMSR2 extent & area calculation
« Reply #1736 on: July 24, 2015, 08:19:55 PM »
On the latest map there is still some low concentration ice blocking the passage. I think you should wait for a path with zero ice before calling it open.

Also I think the route south of New Siberian Islands has large areas with water 6 ft deep at most. If you are traveling by ship rather than boat/yacht with a draft of over 6ft you probably want or need to stay north of New Siberian Islands and that doesn't look so clear.

(I gather that from ship's perspective 30% concentration will look impenetrable. Not sure if dark blue 18% might look nagivable but 74% of light pink won't be.)

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Re: Home brew AMSR2 extent & area calculation
« Reply #1737 on: July 24, 2015, 09:58:34 PM »
I think it is about 6m deep; not 6ft.

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Re: Home brew AMSR2 extent & area calculation
« Reply #1738 on: July 24, 2015, 10:33:29 PM »
the ever reliable Wikipedia says the NSR goes through the sannikov strait, through the middle of the island group

https://en.m.wikipedia.org/wiki/Northern_Sea_Route

dmarcus

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Re: Home brew AMSR2 extent & area calculation
« Reply #1739 on: July 25, 2015, 05:00:04 AM »
A more detailed map of the NSR:

http://www.fni.no/insrop/nsrmap.jpg

Jim Hunt

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Re: Home brew AMSR2 extent & area calculation
« Reply #1740 on: July 25, 2015, 11:33:11 AM »
I just posted a Sentinel image on the NSR thread!
"The evil that is in the world always comes from ignorance, and good intentions may do as much harm as malevolence, if they lack understanding." Albert Camus, The Plague

Wipneus

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Re: Home brew AMSR2 extent & area calculation
« Reply #1741 on: July 28, 2015, 11:34:57 AM »
I posted an animation of the Beaufort nearly two weeks ago- http://forum.arctic-sea-ice.net/index.php/topic,382.msg56893.html#msg56893

Here is the sequel, big floes on the outside of the pack keep getting smaller and eventually disintegration. More inside the pack it is only the smaller floes that can seen visibly melting. Some ice is supplied from the M'Clure Strait.

seaicesailor

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Re: Home brew AMSR2 extent & area calculation
« Reply #1742 on: July 28, 2015, 05:17:12 PM »
I posted an animation of the Beaufort nearly two weeks ago- http://forum.arctic-sea-ice.net/index.php/topic,382.msg56893.html#msg56893

Here is the sequel, big floes on the outside of the pack keep getting smaller and eventually disintegration. More inside the pack it is only the smaller floes that can seen visibly melting. Some ice is supplied from the M'Clure Strait.

Nice

epiphyte

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Re: Home brew AMSR2 extent & area calculation
« Reply #1743 on: July 28, 2015, 05:36:27 PM »
That sudden darkening of the big floes (and not just those closest to the coast) in the last frame is very telling. They may still have the same area - but they're essentially gone.

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Re: Home brew AMSR2 extent & area calculation
« Reply #1744 on: July 28, 2015, 05:47:23 PM »
That sudden darkening of the big floes (and not just those closest to the coast) in the last frame is very telling. They may still have the same area - but they're essentially gone.

There are several reasons that can cause day-to-day darkening (and lightening of course) unrelated to the immediate disintegration of the floes. Temperature is one, temperatures are hovering up an below zero causing dry surfaces to get whet an back. There is a little arctic low right over the area causing swings in vapour and liquid water in clouds causing some trouble for the weather filters.


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Re: Home brew AMSR2 extent & area calculation
« Reply #1745 on: July 29, 2015, 07:47:39 AM »
Wipneus, I have a stupid question.

Do you know why there is quite a big gap between the extent from UH AMSR2 3.125 and L3 JAXA AMSR2 10 km since early June (in your extent graph on page 1)?
Before that time the trends were pretty close.
Has this something to do with the greater resolution of UH AMSR2 3.125 and the fact that the ice disperses as the melt progresses (if that is even true)?

Many thanks

Wipneus

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Re: Home brew AMSR2 extent & area calculation
« Reply #1746 on: July 29, 2015, 08:44:36 AM »
Wipneus, I have a stupid question.

Do you know why there is quite a big gap between the extent from UH AMSR2 3.125 and L3 JAXA AMSR2 10 km since early June (in your extent graph on page 1)?
Before that time the trends were pretty close.
Has this something to do with the greater resolution of UH AMSR2 3.125 and the fact that the ice disperses as the melt progresses (if that is even true)?

Many thanks

Well spotted, not a stupid question at all. It has to do the way Jaxa calculates ice concentration from the AMSR2 microwave measurements, in short the "algorithm".
Jaxa uses an algorithm called Bootstrap, designed by J. Comiso from NASA's Goddard Space Flight Centre. A modification, I think special to Jaxa's calculation, adjusts some parameters during the melting season that compensates for some (but not all) effects due to melting ice surfaces.
That parameter change is fixed on 1st June and ends on 15th October.

The effect of this is I think what you are seeing, the same was visible in 2014.

Resolution has the effect you describe, it is just not as visible in the graphs due to the more gradual increasing effect during the season.

The Jaxa algorithm is described in a document "Descriptions of GCOM-W1 AMSR2
Level 1R and Level 2 Algorithms" available on the GCOM-W1 website https://gcom-w1.jaxa.jp/ (free registration required).

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Re: Home brew AMSR2 extent & area calculation
« Reply #1747 on: July 30, 2015, 09:01:07 AM »
Introducing two more graphs: extent and area of the restricted arctic basin (CAB+Beaufort+Chukchi+ESS+Laptev) for years 2012, 2013, 2014 and 2015.

This calculated  from three sea ice concentration data sets ( UH ASI AMSR2, Jaxa AMSR2 and NSIDC)

Greens are Jaxa, blue's are UH ASI AMSR2, reds are NSIDC), they are shifted u/d (and so have different y-axis's) for clarity.

The UH ASI line for 2012 is taken from the SSMIS data set. This data seems quite reasonably comparative to the AMSR2 data set but it adds another uncertainty so be extra careful here.



LINK



LINK

I think the graphs speak for themselves...

Wipneus

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Re: Home brew AMSR2 extent & area calculation
« Reply #1748 on: July 30, 2015, 09:21:42 AM »
Update 20150729.
Changes from 20150722.

Extent: -567.9 (-284k vs 2014, -133k vs 2013, +372k vs 2012)
Area: -605.9 (-591k vs 2014, -360k vs 2013, +20k vs 2012)

This week the total sea ice extent and area declined on average by about -80k/day, a substantial slow down compared with last week's -130k/day. Compared with previous years the decline was larger in 2012 and lower in 2014.
Regionally it the regions on the east, from ESS to Barents, where the numbers dropped fasted. The decline in the Barents Sea, nearly ice-free, is now eating into the CAB, making it join the party.
On the other end of the scale the drops in the Beaufort ice cover (and the remaining ice in Chukchi)  nearly stalled, both area and extent. Atmospheric temperatures below zero seem to show in the numbers.
Hudson and Baffin regions still have anomalous (compared with recent history) ice that will probably go before the minimum is reached, amounting to about 180k. One way to look at the remaining weeks of the melting season is to look just at the regions in the arctic basin. That is what I did in these graphs:
https://sites.google.com/site/arctischepinguin/home/amsr2/grf/basin-extent-multiprod.png
https://sites.google.com/site/arctischepinguin/home/amsr2/grf/basin-area-multiprod.png
(I see that wanderer just posted these again)
In these graphs 2015 seems to be tracking 2012, leaving 2013 and 2014 behind. See also that most of the ice is lost in what remains of this melting season, at least in the previous three years. That requires declines in August greater than in July.
So will the declines in the Basin take up? Will the Beaufort hiatus continue and will the strong melt from the Kara/Barents section continue into the CAB?
The season stays interesting until the end.
 
You will find the updated graphs in the top post

The details (in 1000 km2):


Extent:
   Central Arctic Basin       East Siberian Sea              Laptev Sea
                  -96.9                  -115.8                  -111.3
               Kara Sea             Barents Sea           Greenland Sea
                  -53.0                   -19.1                   -35.3
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                  -41.7                     0.0                   -44.7
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                  -43.6                    -8.7                     1.9
             Bering Sea          Sea of Okhotsk            Total Extent
                   -0.7                     0.8                  -567.9

Area:
   Central Arctic Basin       East Siberian Sea              Laptev Sea
                 -185.6                  -140.2                  -105.4
               Kara Sea             Barents Sea           Greenland Sea
                  -38.4                   -16.3                   -22.7
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                  -39.1                     0.0                   -35.0
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                  -22.0                    11.7                   -12.9
             Bering Sea          Sea of Okhotsk              Total Area
                   -0.6                     0.5                  -605.9

« Last Edit: July 30, 2015, 09:27:33 AM by Wipneus »

seaicesailor

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Re: Home brew AMSR2 extent & area calculation
« Reply #1749 on: July 30, 2015, 09:31:28 AM »

One note: Beaufort has been getting some import of MYI from CAB for the past days. Thar explains why increase in area.