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gerontocrat

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Re: 2020 Sea ice area and extent data
« Reply #1300 on: August 18, 2020, 09:32:34 PM »
NSIDC Graphs...The Russian Shore

As the melting season draws to a close, attention switches from the leading indicator - Area, to the lagging indicator - Extent, as that is what goes into the record books.

The Kara & the Laptev seas are pretty much kaput.

There is some ice left in the ESS. Will it totally melt out?
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Lord M Vader

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Re: 2020 Sea ice area and extent data
« Reply #1301 on: August 18, 2020, 10:08:15 PM »
This might be of interesting: it seems like NSIDC has revised the 2019 minima upward. This revision means that the 2019 seasonal minima nominally was the fourth lowest behind 2012, 2007 and 2016.
M'lud,

??Are you referring to the graph in ..
Central Arctic Sea - approximates to North of 80

because that is for the Central Arctic Sea only.

Gerontocrat: No, I mean the data that you see at NSIDC Charctic Sea Ice. Look at https://nsidc.org/arcticseaicenews/charctic-interactive-sea-ice-graph/. Now, compare with the number NSIDC did present after last years minimum. http://nsidc.org/arcticseaicenews/2019/09/

The preliminary minima was 4,15 Mn km2 but when you look at the Charctic Sea Ice number this value has been raised to 4,19 Mn km2. While it, according to what NSIDC has written earlier, still is a statistical tie with 2007 and 2016 it is nominally the fourth lowest.

Juan C. García

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Re: 2020 Sea ice area and extent data
« Reply #1302 on: August 19, 2020, 12:36:52 AM »
Gerontocrat: No, I mean the data that you see at NSIDC Charctic Sea Ice. Look at https://nsidc.org/arcticseaicenews/charctic-interactive-sea-ice-graph/. Now, compare with the number NSIDC did present after last years minimum. http://nsidc.org/arcticseaicenews/2019/09/

The preliminary minima was 4,15 Mn km2 but when you look at the Charctic Sea Ice number this value has been raised to 4,19 Mn km2. While it, according to what NSIDC has written earlier, still is a statistical tie with 2007 and 2016 it is nominally the fourth lowest.

You are right, Lord M Vader.
And I think it's not the first time that happens.
Look at 2016:

5 day NSIDC extent crept upward by 2k yesterday, so the likely minimum will be 4.137 million km2 from September 10th.

Quote
On September 10, Arctic sea ice extent stood at 4.14 million square kilometers (1.60 million square miles).
http://nsidc.org/arcticseaicenews/2016/09/

On the original daily values, it seems that the minimun NSIDC 5 day-trailing average of 2016 and 2019 were lower than 2007.
« Last Edit: August 19, 2020, 01:04:10 AM by Juan C. García »
Which is the best answer to Sep-2012 ASI lost (compared to 1979-2000)?
50% [NSIDC Extent] or
73% [PIOMAS Volume]

Volume is harder to measure than extent, but 3-dimensional space is real, 2D's hide ~50% thickness gone.
-> IPCC/NSIDC trends [based on extent] underestimate the real speed of ASI lost.

Juan C. García

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Re: 2020 Sea ice area and extent data
« Reply #1303 on: August 19, 2020, 01:26:03 AM »
Which is the best answer to Sep-2012 ASI lost (compared to 1979-2000)?
50% [NSIDC Extent] or
73% [PIOMAS Volume]

Volume is harder to measure than extent, but 3-dimensional space is real, 2D's hide ~50% thickness gone.
-> IPCC/NSIDC trends [based on extent] underestimate the real speed of ASI lost.

Juan C. García

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Re: 2020 Sea ice area and extent data
« Reply #1304 on: August 19, 2020, 05:32:57 AM »
[ADS NIPR VISHOP (JAXA)] Arctic Sea Ice Extent.

August 18th, 2020:
     4,680,152 km2, a century drop of -101,451 km2.
     2020 is 3rd lowest on record.
     Highlighted 2020 & the 4 years with a daily lowest min in Sept. (2012, 2019, 2016 & 2007).
     In the graph are today's 10 lowest years.
     Source: https://ads.nipr.ac.jp/vishop/#/extent
« Last Edit: August 19, 2020, 05:44:01 AM by Juan C. García »
Which is the best answer to Sep-2012 ASI lost (compared to 1979-2000)?
50% [NSIDC Extent] or
73% [PIOMAS Volume]

Volume is harder to measure than extent, but 3-dimensional space is real, 2D's hide ~50% thickness gone.
-> IPCC/NSIDC trends [based on extent] underestimate the real speed of ASI lost.

gerontocrat

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Re: 2020 Sea ice area and extent data
« Reply #1305 on: August 19, 2020, 10:17:02 AM »
JAXA ARCTIC SEA ICE EXTENT:  4,680,152 KM2 as at 18-Aug-2020

- Extent loss on this day 101k, 48 k more than the average loss on this day (of the last 10 years) of 53k,
- Extent loss from maximum on this date is 9,767 k, 676 k, 7.4% more than the 10 year average of 9,092 k.
- Extent is at position #3 in the satellite record
- Extent is  0 k LESS than 2019,
- Extent is  336 k LESS than 2016,
- Extent is  374 k MORE than 2012
- Extent is  315 k LESS than 2007
_____________________________________________
On average 91.4% of melting from maximum to minimum done, and 27 days to minimum

Projections. (Table JAXA-Arc1)

Average remaining melt (of the last 10 years) would produce a minimum in Sept 2020 of 3.82 million km2, 0.64 million km2 above the 2012 minimum of 3.18 million km2.

For a record low, remaining melt needs to be  74.9% or more above average.
For the 2020 minimum to be above the 2019 minimum of 3.96 million km2,  remaining melt needs to be  16.2% or more below the previous 10 years average remaining melt.
_____________________________________
What a difference 5 days of above average sea ice extent losses, including 2 century breaks, makes. Suddenly a 2nd lowest minimum by a decent margin looks very possible.
How long will this end-of-season gallop last?
How vulnerable is all that low concentration ice?
Will the ice edge breach the 85 North barrier?
How much oomph is left in the ocean heat collected this year?


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N.B. Click once on an image to make it full-size
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gerontocrat

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Re: 2020 Sea ice area and extent data
« Reply #1306 on: August 19, 2020, 10:25:07 AM »
JAXA Arctic Data.. a bit more

The plume of projections using previous years' remaining melt still shows a range of minima outcomes of over half a million km2.

I attach the table of this day's extent compared with previous years' minima. Still a way to go for 2nd place.
"Para a Causa do Povo a Luta Continua!"
"And that's all I'm going to say about that". Forrest Gump
"Damn, I wanted to see what happened next" (Epitaph)

glennbuck

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Re: 2020 Sea ice area and extent data
« Reply #1307 on: August 19, 2020, 02:36:12 PM »
NSIDC Daily Area: August 18

Arctic Sea ice area: 2,966,377 million km^2.

Change from yesterday: 38,948 km^2

August 18, daily Area and Extent 2020 below.


(2020) Area daily: 2.966                            Extent daily : 4.930       

NSIDC: September daily area minimum     NSIDC: September daily extent minimum

(2012) 2.241                                             : 3.340  <<  Sep  16
(2016) 2.477                                             : 4.145         Sep   7               
(2011) 2.940                                             : 4.333         Sep   8
(2019) 2.960                                             : 4.166         Sep 18
(2017) 3.020                                             : 4.635         Sep 13
(2007) 3.050                                             : 4.155         Sep 18
(2008) 3.120                                             : 4.586         Sep 19
(2015) 3.160                                             : 4.387         Sep   8
(2018) 3.270                                             : 4.630         Sep 21
« Last Edit: August 20, 2020, 12:44:23 AM by glennbuck »

gerontocrat

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Re: 2020 Sea ice area and extent data
« Reply #1308 on: August 19, 2020, 03:27:29 PM »
NSIDC Total Area as at 18-Aug-2020 (5 day trailing average) 3,038,985 KM2         
         
Total Area         
 3,038,985    km2      
-593,536    km2   <   2010's average.
-74,950    km2   <   2019
-1,430,563    km2   <   2000's average.
         
Total Change   -28    k   loss
Peripheral Seas   -2    k   loss
Central Seas___   -25    k   loss
         
Peripheral Seas         
Okhotsk______    0    k   gain
Bering _______   -0    k   loss
Hudson Bay___   -1    k   loss
Baffin  Bay____   -1    k   loss
St Lawrence___    -    k   loss
Greenland____   -0    k   loss
Barents ______   -0    k   loss
         
Central Arctic  Ocean Seas         
Chukchi______   -11    k   loss
Beaufort_____   -5    k   loss
CAA_________   -3    k   loss
East Siberian__   -6    k   loss
Central Arctic_    3    k   gain
Laptev_______   -1    k   loss
Kara_________   -2    k   loss
         
Sea ice area loss on this day 28 k, 22 k less than the 2010's average loss of 50 k         
         
- 2020 area is at position #2 in the satellite record.         
- 2020 Area is 594 k less than the 2010's average         
- 2020 Area is 1,431 k less than the 2000's average         
- 2020 Area is 244 k less than 2016         
- 2020 Area is 75 k less than 2019          
- 2020 Area is 108 k more than 2012         
___________________________________________         
NSIDC Total EXTENT as at 18-Aug-2020 (5 day trailing average) 5,044,210 KM2         
         
NSIDC Sea ice EXTENT loss on this day 90 k, 31 k more than the 2010's average loss of 59k         
         
- 2020 EXTENT is at position #3 in the satellite record.         
- 2020 EXTENT is 407 k less than the 2010's average         
- 2020 EXTENT is 1,427 k less than the 2000's average         
- 2020 EXTENT is 263 k less than 2016         
- 2020 EXTENT is 168 k more than 2019          
- 2020 EXTENT is 427 k more than 2012

_____________________________________
Area losses continue to decline, daily extent loss only 27k. Is this a trend or is it just because the NSIDC low-res sensor cannot process well the multiplicity of small open water patches in, for example, the Beaufort and ESS as shown in the high-res AMSR2 images? The next few days will tell us.         
___________________________________________         
Note: Click once on each image to see it full-size         
"Para a Causa do Povo a Luta Continua!"
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"Damn, I wanted to see what happened next" (Epitaph)

gerontocrat

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Re: 2020 Sea ice area and extent data
« Reply #1309 on: August 19, 2020, 06:32:03 PM »
NSIDC has done a mid-August update. https://nsidc.org/arcticseaicenews/

It includes a projection of the 2020 minimum extent - tends to just above 4 million km2.

Given JAXA data tends to be a bit lower, it corresponds well to a projection for JAXA extent of a bit under 4 million km2.

« Last Edit: August 19, 2020, 06:38:19 PM by gerontocrat »
"Para a Causa do Povo a Luta Continua!"
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Alphabet Hotel

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Re: 2020 Sea ice area and extent data
« Reply #1310 on: August 19, 2020, 10:42:48 PM »
NSIDC daily extent

7-day average:  (4930 − 5579) / 7  =  −93
14-day average: (4930 − 5783) / 14  =  −61

2020-08-04  5.783
2020-08-05  5.860    +77
2020-08-06  5.812    −48
2020-08-07  5.760    −52
2020-08-08  5.645  −115
2020-08-09  5.549    −96
2020-08-10  5.595    +46
2020-08-11  5.579    −16
2020-08-12  5.484    −95
2020-08-13  5.383  −101
2020-08-14  5.137  −246
2020-08-15  5.200    +63
2020-08-16  5.069  −131
2020-08-17  4.957  −112
2020-08-18  4.930    −27

Tor Bejnar

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Re: 2020 Sea ice area and extent data
« Reply #1311 on: August 20, 2020, 12:25:30 AM »
https://sites.google.com/view/pettitclimategraphs
The graph at the link (scroll down to 'Extent') shows the 'days until below 5.0 m' lasted 16 days and we're 2 days into 'days until below 4.0 m'
Arctic ice is healthy for children and other living things.

Juan C. García

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Re: 2020 Sea ice area and extent data
« Reply #1312 on: August 20, 2020, 05:31:41 AM »
[ADS NIPR VISHOP (JAXA)] Arctic Sea Ice Extent.

August 19th, 2020:
     4,559,264 km2, a century drop of -120,888 km2.
     2020 is 3rd lowest on record.
     Highlighted 2020 & the 4 years with a daily lowest min in Sept. (2012, 2019, 2016 & 2007).
     In the graph are today's 10 lowest years.
     Source: https://ads.nipr.ac.jp/vishop/#/extent
« Last Edit: August 20, 2020, 05:42:13 AM by Juan C. García »
Which is the best answer to Sep-2012 ASI lost (compared to 1979-2000)?
50% [NSIDC Extent] or
73% [PIOMAS Volume]

Volume is harder to measure than extent, but 3-dimensional space is real, 2D's hide ~50% thickness gone.
-> IPCC/NSIDC trends [based on extent] underestimate the real speed of ASI lost.

Lord M Vader

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Re: 2020 Sea ice area and extent data
« Reply #1313 on: August 20, 2020, 06:27:58 AM »
Only 560K left until we go below 4Mn.....

Rodius

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Re: 2020 Sea ice area and extent data
« Reply #1314 on: August 20, 2020, 06:31:16 AM »
Only 560K left until we go below 4Mn.....

Or 5 or 6 days at this rate.
Surely that wont happen though.....

Alison

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Re: 2020 Sea ice area and extent data
« Reply #1315 on: August 20, 2020, 06:59:40 AM »
Good chance of going second, though :)

gerontocrat

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Re: 2020 Sea ice area and extent data
« Reply #1316 on: August 20, 2020, 08:33:44 AM »
JAXA ARCTIC SEA ICE EXTENT:  4,559,264 KM2 as at 19-Aug-2020

- Extent loss on this day 121k, 73 k more than the average loss on this day (of the last 10 years) of 48k,
- Extent loss from maximum on this date is 9,888 k, 749 k, 8.2% more than the 10 year average of 9,140 k.
- Extent is at position #3 in the satellite record
- Extent is  24 k MORE than 2019,
- Extent is  412 k LESS than 2016,
- Extent is  333 k MORE than 2012
- Extent is  389 k LESS than 2007
_____________________________________________
On average 91.8% of melting from maximum to minimum done, and 26 days to minimum

Projections. (Table JAXA-Arc1)

Average remaining melt (of the last 10 years) would produce a minimum in Sept 2020 of 3.75 million km2, 0.57 million km2 above the 2012 minimum of 3.18 million km2.

For a record low, remaining melt needs to be  70.3% or more above average.
For the 2020 minimum to be above the 2019 minimum of 3.96 million km2,  remaining melt needs to be  26.1% or more below the previous 10 years average remaining melt.
____________________________________________
Once again, a few days very high extent losses make a 2nd lowest extent minimum more likely than not, and by a significant amount below 2019.
And a quick look at today's Univ Bremen AMSR2 images reinforces that.

______________________________
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gerontocrat

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Re: 2020 Sea ice area and extent data
« Reply #1317 on: August 20, 2020, 08:40:00 AM »
JAXA data - a bit more.

The table attached shows extent on this day is already the 10th lowest minimum in the satellite record.

The plume of projections is now firmly below 4 milliom km2 again.
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Neven

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Re: 2020 Sea ice area and extent data
« Reply #1318 on: August 20, 2020, 09:58:58 AM »
2020 has recorded 28 century breaks in the JAXA AMSR-2 dataset so far, and is now in second place (2007 had 27 CBs in total). 2012 stil holds the record with 41 CBs, but this also had to do with the use of WindSat data in the transition period between AMSR-E and AMSR2.
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gerontocrat

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Re: 2020 Sea ice area and extent data
« Reply #1319 on: August 20, 2020, 03:17:19 PM »
NSIDC Total Area as at 19-Aug-2020 (5 day trailing average) 3,014,006 KM2         
         
Total Area         
 3,014,006    km2      
-572,218    km2   <   2010's average.
-88,515    km2   <   2019
-1,425,245    km2   <   2000's average.
         
Total Change   -25    k   loss
Peripheral Seas   -3    k   loss
Central Seas___   -22    k   loss
         
Peripheral Seas         
Okhotsk______    0    k   gain
Bering _______    0    k   gain
Hudson Bay___   -0    k   loss
Baffin  Bay____   -1    k   loss
St Lawrence___    -    k   loss
Greenland____   -2    k   loss
Barents ______   -0    k   loss
         
Central Arctic  Ocean Seas         
Chukchi______   -10    k   loss
Beaufort_____   -3    k   loss
CAA_________   -0    k   loss
East Siberian__   -7    k   loss
Central Arctic_   -1    k   loss
Laptev_______   -0    k   loss
Kara_________   -1    k   loss
         
Sea ice area loss on this day 25 k, 21 k less than the 2010's average loss of 46 k         
         
- 2020 area is at position #2 in the satellite record.         
- 2020 Area is 572 k less than the 2010's average         
- 2020 Area is 1,425 k less than the 2000's average         
- 2020 Area is 201 k less than 2016         
- 2020 Area is 89 k less than 2019          
- 2020 Area is 129 k more than 2012         
___________________________________________         
NSIDC Total EXTENT as at 19-Aug-2020 (5 day trailing average) 4,979,881 KM2         
         
NSIDC Sea ice EXTENT loss on this day 64 k, 10 k more than the 2010's average loss of 54k         
         
- 2020 EXTENT is at position #3 in the satellite record.         
- 2020 EXTENT is 417 k less than the 2010's average         
- 2020 EXTENT is 1,430 k less than the 2000's average         
- 2020 EXTENT is 265 k less than 2016         
- 2020 EXTENT is 143 k more than 2019          
- 2020 EXTENT is 426 k more than 2012

____________________________________________
Area losses continue to decline. Daily extent loss up to 64k and above average, but well below the JAXA extent loss. Is this a trend or is it still just because the NSIDC low-res sensor cannot process well the multiplicity of small open water patches in, for example, the Beaufort and ESS as shown in the high-res AMSR2 images (and the PolarStern pictures from the North Pole)? Intriguing, n'est-ce pas?            
___________________________________________         
Note: Click once on each image to see it full-size         
"Para a Causa do Povo a Luta Continua!"
"And that's all I'm going to say about that". Forrest Gump
"Damn, I wanted to see what happened next" (Epitaph)

Alphabet Hotel

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Re: 2020 Sea ice area and extent data
« Reply #1320 on: August 20, 2020, 05:44:04 PM »
NSIDC daily extent

7-day average:  (4816 − 5484) / 7  =  −95
14-day average: (4816 − 5860) / 14  =  −75

2020-08-05  5.860
2020-08-06  5.812    −48
2020-08-07  5.760    −52
2020-08-08  5.645  −115
2020-08-09  5.549    −96
2020-08-10  5.595    +46
2020-08-11  5.579    −16
2020-08-12  5.484    −95
2020-08-13  5.383  −101
2020-08-14  5.137  −246
2020-08-15  5.200    +63
2020-08-16  5.069  −131
2020-08-17  4.957  −112
2020-08-18  4.930    −27
2020-08-19  4.816  −114

gerontocrat

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Re: 2020 Sea ice area and extent data
« Reply #1321 on: August 20, 2020, 06:03:45 PM »
And now for something completely different....

NSIDC has published their mask file as a txt file. So I dragged it into my spreadsheet file and played with it. It is simply an array 304 x 448, each box for a pixel with the code for the sea in it.

From that one can get a map simply by copying the whole lot into Paint and reducing the size.-
See attachments 0 & 1.

Then I told the spreadsheet to pull out the number of pixels for each sea and calculate the area using 25 x 25 = 625 km2 as the multiplier. That, of course does not produce an accurate result as the pixel size varies as the array is applied to a curved surface.

But it does show that back in 2007, when Meier et al made the mask, they were assuming the possibility of a much greater area of ice at maximum -especially in the Okhotsk, Bering, St Lawrence, Baffin, Greenland & Barents Seas.

see attachment 2.

Fascinating stuff.
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glennbuck

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Re: 2020 Sea ice area and extent data
« Reply #1322 on: August 20, 2020, 06:13:24 PM »
NSIDC Daily Area: August 19

Arctic Sea ice area: 2,950,099 million km^2.

Change from yesterday: 16,278 km^2

August 19, 2020 daily Area and Extent below.

Daily Sea ice Area moves into the 4th place record today at 2.950 with 30 or less days to daily minimum, ahead of 2019 Area daily minimum, 18th September at 2.960

(2020) NSIDC: Area daily: 2.950               NSIDC: Extent daily: 4.816       

NSIDC: September daily area minimum     NSIDC: September daily extent minimum

(2012) 2.241                                             : 3.340  <<  Sep  16
(2016) 2.477                                             : 4.145         Sep   7               
(2011) 2.940                                             : 4.333         Sep   8
(2019) 2.960                                             : 4.166         Sep 18
(2017) 3.020                                             : 4.635         Sep 13
(2007) 3.050                                             : 4.155         Sep 18
(2008) 3.120                                             : 4.586         Sep 19
(2015) 3.160                                             : 4.387         Sep   8
(2018) 3.270                                             : 4.630         Sep 21
« Last Edit: August 21, 2020, 06:43:25 AM by glennbuck »

Stephan

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Re: 2020 Sea ice area and extent data
« Reply #1323 on: August 20, 2020, 08:51:41 PM »
If the decrease rate of Chukchi of the last week continues for two more days Chukchi Sea will be ice-free.
It is too late just to be concerned about Climate Change

Juan C. García

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Re: 2020 Sea ice area and extent data
« Reply #1324 on: August 21, 2020, 05:32:50 AM »
[ADS NIPR VISHOP (JAXA)] Arctic Sea Ice Extent.

August 20th, 2020:
     4,484,792 km2, a drop of -74,472 km2.
     2020 is now 2nd lowest on record.
     Highlighted 2020 & the 4 years with a daily lowest min in Sept. (2012, 2019, 2016 & 2007).
     In the graph are today's 10 lowest years.
     Source: https://ads.nipr.ac.jp/vishop/#/extent
« Last Edit: August 21, 2020, 05:43:40 AM by Juan C. García »
Which is the best answer to Sep-2012 ASI lost (compared to 1979-2000)?
50% [NSIDC Extent] or
73% [PIOMAS Volume]

Volume is harder to measure than extent, but 3-dimensional space is real, 2D's hide ~50% thickness gone.
-> IPCC/NSIDC trends [based on extent] underestimate the real speed of ASI lost.

gerontocrat

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Re: 2020 Sea ice area and extent data
« Reply #1325 on: August 21, 2020, 11:15:53 AM »
JAXA ARCTIC SEA ICE EXTENT:  4,484,792 KM2 as at 20-Aug-2020

- Extent loss on this day 74k, 27 k more than the average loss on this day (of the last 10 years) of 47k,
- Extent loss from maximum on this date is 9,963 k, 776 k, 8.4% more than the 10 year average of 9,187 k.
- Extent is at position #2 in the satellite record
- Extent is  23 k LESS than 2019,
- Extent is  438 k LESS than 2016,
- Extent is  341 k MORE than 2012
- Extent is  393 k LESS than 2007
_____________________________________________
On average 92.3% of melting from maximum to minimum done, and 25 days to minimum

Projections. (Table JAXA-Arc1)

Average remaining melt (of the last 10 years) would produce a minimum in Sept 2020 of 3.72 million km2, 0.54 million km2 above the 2012 minimum of 3.18 million km2.

For a record low, remaining melt needs to be  71.1% or more above average.

For the 2020 minimum to be above the 2019 minimum of 3.96 million km2,  remaining melt needs to be  31.3% or more below the previous 10 years average remaining melt.

Remaining melt in all years back to 2007 would give a 2020 minimum below 2019 but above 2020, i.e. 2nd lowest.
______________________________
N.B. Click once on an image to make it full-size
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gerontocrat

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Re: 2020 Sea ice area and extent data
« Reply #1326 on: August 21, 2020, 11:25:16 AM »
JAXA Extent... a bit more

I attach the table comparing this day's extent with previous years' minima to supplement Juan's table.
2020 is currently 9th lowest.
Tomorrow it is very likely to be 7th lowest.
Not long after it will be 5th lowest - and after that...?

I also attach the plume of projections of the minimum from previous years' extent losses.
Still a big range.

I also attach the history of extent losses for this season. It looks likely that the 10 days or so of very low extent losses in late July and early August kyboshed the chances of a 2020 record low minimum.

« Last Edit: August 21, 2020, 03:17:50 PM by gerontocrat »
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Re: 2020 Sea ice area and extent data
« Reply #1327 on: August 21, 2020, 02:07:44 PM »
NSIDC Daily Area: August 20

Arctic Sea ice area: 2,917,005 million km^2.

Change from yesterday: 33,094 km^2

August 20, 2020 daily Area and Extent below.

Daily Sea ice Area moves into the 3rd place record today, 2.917 with 30 or less days to daily minimum, ahead of 2011 Area daily minimum, 8th September at 2.940

(2020) NSIDC: Area daily: 2.917               NSIDC: Extent daily: 4.704       

NSIDC: September daily area minimum     NSIDC: September daily extent minimum

(2012) 2.241                                             : 3.340  <<  Sep  16
(2016) 2.477                                             : 4.145         Sep   7               
(2011) 2.940                                             : 4.333         Sep   8
(2019) 2.960                                             : 4.166         Sep 18
(2017) 3.020                                             : 4.635         Sep 13
(2007) 3.050                                             : 4.155         Sep 18
(2008) 3.120                                             : 4.586         Sep 19
(2015) 3.160                                             : 4.387         Sep   8
(2018) 3.270                                             : 4.630         Sep 21
« Last Edit: August 21, 2020, 07:53:51 PM by glennbuck »

gerontocrat

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Re: 2020 Sea ice area and extent data
« Reply #1328 on: August 21, 2020, 03:23:59 PM »
NSIDC Total Area as at 20-Aug-2020 (5 day trailing average) 2,982,441 KM2         
         
Total Area         
 2,982,441    km2      
-565,587    km2   <   2010's average.
-109,389    km2   <   2019
-1,432,073    km2   <   2000's average.
         
Total Change   -32    k   loss
Peripheral Seas   -4    k   loss
Central Seas___   -27    k   loss
         
Peripheral Seas         
Okhotsk______    0    k   gain
Bering _______    0    k   gain
Hudson Bay___   -3    k   loss
Baffin  Bay____   -1    k   loss
St Lawrence___    -    k   loss
Greenland____   -1    k   loss
Barents ______   -0    k   loss
         
Central Arctic  Ocean Seas         
Chukchi______   -9    k   loss
Beaufort_____   -3    k   loss
CAA_________   -4    k   loss
East Siberian__   -8    k   loss
Central Arctic_   -3    k   loss
Laptev_______    0    k   gain
Kara_________   -2    k   loss
         
Sea ice area loss on this day 32 k, 6 k less than the 2010's average loss of 38 k         
         
- 2020 area is at position #2 in the satellite record.         
- 2020 Area is 566 k less than the 2010's average         
- 2020 Area is 1,432 k less than the 2000's average         
- 2020 Area is 192 k less than 2016         
- 2020 Area is 109 k less than 2019          
- 2020 Area is 131 k more than 2012         
___________________________________________         
NSIDC Total EXTENT as at 20-Aug-2020 (5 day trailing average) 4,880,673 KM2         
         
NSIDC Sea ice EXTENT loss on this day 99 k, 47 k more than the 2010's average loss of 52k         
         
- 2020 EXTENT is at position #3 in the satellite record.         
- 2020 EXTENT is 464 k less than the 2010's average         
- 2020 EXTENT is 1,465 k less than the 2000's average         
- 2020 EXTENT is 292 k less than 2016         
- 2020 EXTENT is 73 k more than 2019          
- 2020 EXTENT is 400 k more than 2012

___________________________________________
To maintain such high extent losses is not usual at this point in the melting season.
Area losses gradually ticking up again.      
   
___________________________________________         
Note: Click once on each image to see it full-size         
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gerontocrat

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Re: 2020 Sea ice area and extent data
« Reply #1329 on: August 21, 2020, 03:35:46 PM »
NSIDC - Central Arctic Sea
Both extent and area are currently lowest in the satellite record for the 20th August.
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gerontocrat

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Re: 2020 Sea ice area and extent data
« Reply #1330 on: August 21, 2020, 03:55:08 PM »
NSIDC - some more graphs

The Chukchi sea ice collapsed in a heap quite specatcularly.

Large parts of the Beaufort could do likewise (looking at the AMSR2 Bremen image)- but it's getting a bit late in the day for it all to go.


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Alphabet Hotel

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Re: 2020 Sea ice area and extent data
« Reply #1331 on: August 21, 2020, 04:12:53 PM »
NSIDC daily extent

7-day average:  (4704 − 5383) / 7  =  −97
14-day average: (4704 − 5812) / 14  =  −79

2020-08-06  5.812
2020-08-07  5.760    −52
2020-08-08  5.645  −115
2020-08-09  5.549    −96
2020-08-10  5.595    +46
2020-08-11  5.579    −16
2020-08-12  5.484    −95
2020-08-13  5.383  −101
2020-08-14  5.137  −246
2020-08-15  5.200    +63
2020-08-16  5.069  −131
2020-08-17  4.957  −112
2020-08-18  4.930    −27
2020-08-19  4.816  −114
2020-08-20  4.704  −112

Juan C. García

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Re: 2020 Sea ice area and extent data
« Reply #1332 on: August 22, 2020, 05:34:54 AM »
[ADS NIPR VISHOP (JAXA)] Arctic Sea Ice Extent.

August 21st, 2020:
     4,385,823 km2, an almost century break of -98,969 km2.
     2020 is 2nd lowest on record.
     Highlighted 2020 & the 4 years with a daily lowest min in Sept. (2012, 2019, 2016 & 2007).
     In the graph are today's 10 lowest years.
     Source: https://ads.nipr.ac.jp/vishop/#/extent
« Last Edit: August 22, 2020, 05:44:33 AM by Juan C. García »
Which is the best answer to Sep-2012 ASI lost (compared to 1979-2000)?
50% [NSIDC Extent] or
73% [PIOMAS Volume]

Volume is harder to measure than extent, but 3-dimensional space is real, 2D's hide ~50% thickness gone.
-> IPCC/NSIDC trends [based on extent] underestimate the real speed of ASI lost.

gerontocrat

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Re: 2020 Sea ice area and extent data
« Reply #1333 on: August 22, 2020, 11:55:41 AM »
JAXA ARCTIC SEA ICE EXTENT:  4,385,823 KM2 as at 21-Aug-2020

- Extent loss on this day 99k, 56 k more than the average loss on this day (of the last 10 years) of 43k,
- Extent loss from maximum on this date is 10,062 k, 832 k, 9.0% more than the 10 year average of 9,230 k.
- Extent is at position #2 in the satellite record
- Extent is  85 k LESS than 2019,
- Extent is  509 k LESS than 2016,
- Extent is  313 k MORE than 2012
- Extent is  420 k LESS than 2007
_____________________________________________
On average 92.8% of melting from maximum to minimum done, and 24 days to minimum

Projections. (Table JAXA-Arc1)

Average remaining melt (of the last 10 years) would produce a minimum in Sept 2020 of 3.67 million km2, 0.49 million km2 above the 2012 minimum of 3.18 million km2.

For a record low, remaining melt needs to be  67.7% or more above average.
For the 2020 minimum to be above the 2019 minimum of 3.96 million km2, remaining melt needs to be  40.9% or more below the previous 10 years average remaining melt.

There is a significant area of very low concentration ice remaining, and on average still just over 3 weeks of the melting season to go.

______________________________
N.B. Click once on an image to make it full-size
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gerontocrat

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Re: 2020 Sea ice area and extent data
« Reply #1334 on: August 22, 2020, 12:01:49 PM »
JAXA Data - supplementary info.

I attach the table comparing this day's extent with previous years' minima to supplement Juan's table.
2020 is currently 7th lowest.
Not so long before it is 5th lowest.
And then.......

I also attach the plume of projections of the minimum from previous years' extent losses. 3.5 million km2 suddenly looking more possible.
Still a big range.


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glennbuck

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Re: 2020 Sea ice area and extent data
« Reply #1335 on: August 22, 2020, 02:46:36 PM »
NSIDC Daily Area: August 21

Arctic Sea ice area: 2,835,222 million km^2.

Change from yesterday: 81,783 km^2

August 21, 2020 daily Area and Extent below.


(2020) NSIDC: Area daily: 2.835               NSIDC: Extent daily: 4.630       

NSIDC: September daily area minimum     NSIDC: September daily extent minimum

(2012) 2.241                                             : 3.340  <<  Sep  16
(2016) 2.477                                             : 4.145         Sep   7               
(2011) 2.940                                             : 4.333         Sep   8
(2019) 2.960                                             : 4.166         Sep 18
(2017) 3.020                                             : 4.635         Sep 13
(2007) 3.050                                             : 4.155         Sep 18
(2008) 3.120                                             : 4.586         Sep 19
(2015) 3.160                                             : 4.387         Sep   8
(2018) 3.270                                             : 4.630         Sep 21
« Last Edit: August 22, 2020, 08:06:09 PM by glennbuck »

Alphabet Hotel

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Re: 2020 Sea ice area and extent data
« Reply #1336 on: August 22, 2020, 03:06:54 PM »
NSIDC daily extent

7-day average:  (4630 − 5137) / 7  =  −72
14-day average: (4630 − 5760) / 14  =  −81

2020-08-07  5.760
2020-08-08  5.645  −115
2020-08-09  5.549    −96
2020-08-10  5.595    +46
2020-08-11  5.579    −16
2020-08-12  5.484    −95
2020-08-13  5.383  −101
2020-08-14  5.137  −246
2020-08-15  5.200    +63
2020-08-16  5.069  −131
2020-08-17  4.957  −112
2020-08-18  4.930    −27
2020-08-19  4.816  −114
2020-08-20  4.704  −112
2020-08-21  4.630    −74
« Last Edit: August 22, 2020, 04:35:39 PM by Alphabet Hotel »

gerontocrat

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Re: 2020 Sea ice area and extent data
« Reply #1337 on: August 22, 2020, 03:09:03 PM »
NSIDC Total Area as at 21-Aug-2020 (5 day trailing average) 2,943,940 KM2         
         
Total Area         
 2,943,940    km2      
-570,245    km2   <   2010's average.
-144,822    km2   <   2019
-1,449,614    km2   <   2000's average.
         
Total Change   -39    k   loss
Peripheral Seas   -5    k   loss
Central Seas___   -33    k   loss
         
Peripheral Seas         
Okhotsk______    0    k   gain
Bering _______   -0    k   loss
Hudson Bay___   -3    k   loss
Baffin  Bay____    0    k   gain
St Lawrence___    -    k   loss
Greenland____   -3    k   loss
Barents ______   -0    k   loss
         
Central Arctic  Ocean Seas         
Chukchi______   -5    k   loss
Beaufort_____   -1    k   loss
CAA_________   -4    k   loss
East Siberian__   -9    k   loss
Central Arctic_   -15    k   loss
Laptev_______    0    k   gain
Kara_________   -0    k   loss
         
Sea ice area loss on this day 39 k, 5 k more than the 2010's average loss of 34 k         
         
- 2020 area is at position #2 in the satellite record.         
- 2020 Area is 570 k less than the 2010's average         
- 2020 Area is 1,450 k less than the 2000's average         
- 2020 Area is 206 k less than 2016         
- 2020 Area is 145 k less than 2019          
- 2020 Area is 131 k more than 2012         
___________________________________________         
NSIDC Total EXTENT as at 21-Aug-2020 (5 day trailing average) 4,792,391 KM2         
         
NSIDC Sea ice EXTENT loss on this day 88 k, 39 k more than the 2010's average loss of 49k         
         
- 2020 EXTENT is at position #3 in the satellite record.         
- 2020 EXTENT is 504 k less than the 2010's average         
- 2020 EXTENT is 1,496 k less than the 2000's average         
- 2020 EXTENT is 335 k less than 2016         
- 2020 EXTENT is 16 k more than 2019          
- 2020 EXTENT is 381 k more than 2012
         
___________________________________________         
Note: Click once on each image to see it full-size         
"Para a Causa do Povo a Luta Continua!"
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gerontocrat

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Re: 2020 Sea ice area and extent data
« Reply #1338 on: August 22, 2020, 03:25:52 PM »
NSIDC - Some graphs.

Peripheral Seas Area - very low entirely due to Greenland Sea area, itself very much a function of currently low ice imports from the Fram Strait.

High Arctic Seas Area- 2nd lowest, Central Arctic at lowest but Beaufort Sea Area still high.
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gerontocrat

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Re: 2020 Sea ice area and extent data
« Reply #1339 on: August 22, 2020, 03:32:17 PM »
NSIDC - Some more graphs

Final outcome for the minimum may depend very much on the Central Arctic & the Beaufort seas.

Central Arctic - area losses have resumed, extent losses staying high.

Beaufort - area losses have slowed, extent losses are high but total extent way above 2010's average.
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Re: 2020 Sea ice area and extent data
« Reply #1340 on: August 23, 2020, 05:31:13 AM »
[ADS NIPR VISHOP (JAXA)] Arctic Sea Ice Extent.

August 22nd, 2020:
     4,317,485 km2, a drop of -68,338 km2.
     2020 is 2nd lowest on record.
     Highlighted 2020 & the 4 years with a daily lowest min in Sept. (2012, 2019, 2016 & 2007).
     In the graph are today's 10 lowest years.
     Source: https://ads.nipr.ac.jp/vishop/#/extent
« Last Edit: August 24, 2020, 05:46:47 AM by Juan C. García »
Which is the best answer to Sep-2012 ASI lost (compared to 1979-2000)?
50% [NSIDC Extent] or
73% [PIOMAS Volume]

Volume is harder to measure than extent, but 3-dimensional space is real, 2D's hide ~50% thickness gone.
-> IPCC/NSIDC trends [based on extent] underestimate the real speed of ASI lost.

gerontocrat

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Re: 2020 Sea ice area and extent data
« Reply #1341 on: August 23, 2020, 12:36:44 PM »
JAXA ARCTIC SEA ICE EXTENT:  4,317,485 KM2 as at 22-Aug-2020

- Extent loss on this day 68k, 15 k more than the average loss on this day (of the last 10 years) of 53k,
- Extent loss from maximum on this date is 10,130 k, 847 k, 9.1% more than the 10 year average of 9,283 k.
- Extent is at position #2 in the satellite record
- Extent is  125 k LESS than 2019,
- Extent is  546 k LESS than 2016,
- Extent is  307 k MORE than 2012
- Extent is  422 k LESS than 2007
_____________________________________________
On average 93.3% of melting from maximum to minimum done, and 23 days to minimum

Projections. (Table JAXA-Arc1)

Average remaining melt (of the last 10 years) would produce a minimum in Sept 2020 of 3.65 million km2, 0.47 million km2 above the 2012 minimum of 3.18 million km2.

For a record low, remaining melt needs to be  70.8% or more above average.
For the 2020 minimum to be above the 2019 minimum of 3.96 million km2, remaining melt needs to be  46.5% or more below the previous 10 years average remaining melt.

The range of outcomes of  the previous 10 years remaining melt is from 3.47 to 3.84 million km2..as the season winds down the range decreases.

Although the last 2 days of daily extent losses have declined, they are still well in excess of average for the time of year.
______________________________
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gerontocrat

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Re: 2020 Sea ice area and extent data
« Reply #1342 on: August 23, 2020, 12:41:54 PM »
JAXA Extent - a bit more.

Minima
table attached - extent poised for another step towards the bottom of the table.

Plume of projections attached - another nudge downwards.
"Para a Causa do Povo a Luta Continua!"
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glennbuck

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Re: 2020 Sea ice area and extent data
« Reply #1343 on: August 23, 2020, 02:46:07 PM »
NSIDC Daily Area: August 22

Arctic Sea ice area: 2,777,140 million km^2.

Change from yesterday: 58,082 km^2

August 22, 2020 daily Area and Extent below.


(2020) NSIDC: Area daily: 2.777               NSIDC: Extent daily: 4.577       

NSIDC: September daily area minimum     NSIDC: September daily extent minimum

(2012) 2.241                                             : 3.340  <<  Sep  16
(2016) 2.477                                             : 4.145         Sep   7               
(2011) 2.940                                             : 4.333         Sep   8
(2019) 2.960                                             : 4.166         Sep 18
(2017) 3.020                                             : 4.635         Sep 13
(2007) 3.050                                             : 4.155         Sep 18
(2008) 3.120                                             : 4.586         Sep 19
(2015) 3.160                                             : 4.387         Sep   8
(2018) 3.270                                             : 4.630         Sep 21
« Last Edit: August 25, 2020, 12:53:11 AM by glennbuck »

gerontocrat

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Re: 2020 Sea ice area and extent data
« Reply #1344 on: August 23, 2020, 04:04:53 PM »
NSIDC Total Area as at 22-Aug-2020 (5 day trailing average) 2,898,253 KM2         
         
Total Area         
 2,898,253    km2      
-584,783    km2   <   2010's average.
-181,123    km2   <   2019
-1,479,346    km2   <   2000's average.
         
Total Change   -46    k   loss
Peripheral Seas   -2    k   loss
Central Seas___   -43    k   loss
         
Peripheral Seas         
Okhotsk______    0    k   gain
Bering _______    0    k   gain
Hudson Bay___   -0    k   loss
Baffin  Bay____    1    k   gain
St Lawrence___    -    k   loss
Greenland____   -3    k   loss
Barents ______    0    k   gain
         
Central Arctic  Ocean Seas         
Chukchi______   -4    k   loss
Beaufort_____    0    k   gain
CAA_________   -5    k   loss
East Siberian__   -7    k   loss
Central Arctic_   -30    k   loss
Laptev_______   -0    k   loss
Kara_________    3    k   gain
         
Sea ice area loss on this day 46 k, 15 k more than the 2010's average loss of 31 k         
         
- 2020 area is at position #2 in the satellite record.         
- 2020 Area is 585 k less than the 2010's average         
- 2020 Area is 1,479 k less than the 2000's average         
- 2020 Area is 235 k less than 2016         
- 2020 Area is 181 k less than 2019          
- 2020 Area is 133 k more than 2012         
___________________________________________         
NSIDC Total EXTENT as at 22-Aug-2020 (5 day trailing average) 4,715,451 KM2         
         
NSIDC Sea ice EXTENT loss on this day 77 k, 23 k more than the 2010's average loss of 54k         
         
- 2020 EXTENT is at position #2 in the satellite record.         
- 2020 EXTENT is 526 k less than the 2010's average         
- 2020 EXTENT is 1,520 k less than the 2000's average         
- 2020 EXTENT is 380 k less than 2016         
- 2020 EXTENT is 18 k less than 2019          
- 2020 EXTENT is 370 k more than 2012

____________________________________________
Extent and area losses not that high, but above average for this date.         
___________________________________________         
Note: Click once on each image to see it full-size         
"Para a Causa do Povo a Luta Continua!"
"And that's all I'm going to say about that". Forrest Gump
"Damn, I wanted to see what happened next" (Epitaph)

Alphabet Hotel

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Re: 2020 Sea ice area and extent data
« Reply #1345 on: August 23, 2020, 04:25:19 PM »
NSIDC daily extent

7-day average:  (4577 − 5200) / 7  =  −89
14-day average: (4577 − 5645) / 14  =  −76

2020-08-08  5.645
2020-08-09  5.549    −96
2020-08-10  5.595    +46
2020-08-11  5.579    −16
2020-08-12  5.484    −95
2020-08-13  5.383  −101
2020-08-14  5.137  −246
2020-08-15  5.200    +63
2020-08-16  5.069  −131
2020-08-17  4.957  −112
2020-08-18  4.930    −27
2020-08-19  4.816  −114
2020-08-20  4.704  −112
2020-08-21  4.630    −74
2020-08-22  4.577    −53

gerontocrat

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Re: 2020 Sea ice area and extent data
« Reply #1346 on: August 23, 2020, 05:17:06 PM »
NSIDC Graphs

Once again Central Arctic Sea area and extent losses continue to be high.

Beaufort Sea area losses have stalled, while although extent losses continue, extent is some 250,000 km2 above the 2010's average for this day. Will we see a sudden melt of that large area of 50% concentration ice shown in the Bremen false colour image (as happened in the Chukchi)? Or will it be just a bit too chilly?

"Para a Causa do Povo a Luta Continua!"
"And that's all I'm going to say about that". Forrest Gump
"Damn, I wanted to see what happened next" (Epitaph)

Stephan

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Re: 2020 Sea ice area and extent data
« Reply #1347 on: August 23, 2020, 05:22:43 PM »
Another daily loss of Chukchi Sea Ice Area like yesterday - and the ice area will become negative...
It is too late just to be concerned about Climate Change

ArcticMelt2

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Re: 2020 Sea ice area and extent data
« Reply #1348 on: August 23, 2020, 08:29:14 PM »
Another daily loss of Chukchi Sea Ice Area like yesterday - and the ice area will become negative...

Chukchi Sea has come out on top.

https://twitter.com/AlaskaWx/status/1297566066688712706

Quote
Chukchi Sea ice extent now lowest in the satellite era for this point in autumn (@NSIDC  data) with near record rapid #seaice loss (Aug 2012 slightly greater). Big diffs btwn multi-sensor @NWSAlaska  analyses & passive microwave common in Aug

« Last Edit: August 23, 2020, 08:48:07 PM by ArcticMelt2 »

be cause

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Re: 2020 Sea ice area and extent data
« Reply #1349 on: August 24, 2020, 01:26:46 AM »
  Hi Gerontocrat .. regarding the graphs . As we remarked earlier in the year , early losses in Kara seem to portend larger losses later in the CAB . 2020 is currently @ 150k sqkm ahead of both '12 and '16 , so that correlation continues .
  On closer examination . I realized the current year line ends @ 3.5 days ago .. is that because it is a trailing average ?
  btw .. Thanks for everything you bring to the Forum .. b.c.
2007 + 5 = 2012 + 4 = 2016 + 3 = 2019 + 2 = 2021 + 1 =  ' if only we could have seen it coming ' ...