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Messages - gerontocrat

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1
Permafrost / Re: Arctic Methane Release
« on: January 16, 2019, 06:03:24 PM »

Methane Calthrates at the bottom of the ocean should remain stable due to the sheer pressure and the difficulty of warming the bottom depths. It is an overblown concern that has been studied and largely disproven.

studied and largely disproven.

At the bottom of the ocean - yes, most methane degraded on the way to the surface
In shallow seas with slow methane escape. Yes, most methane degraded on the way to the surface.

Abrupt release in shallow seas (e.g. a goodly part of the ESAS is below 10 metres depth) - No. Shakhova etc have observed such emissions.
Longer and earlier open water seasons will allow increased insolation and warm water intrusion. This may accelerate warming of ocean bottom permafrost and the clathrate lid on free methane under pressure underneath.

Are current emissions sufficient to make a major impact on global methane ppb? No(t yet).
Can this risk be casually dismissed - no.
Is this risk disproven ? No. We don't really know what lies beneath in this vast area of the ocean.

Are current emissions sufficient to make a major impact on methane ppb? No(t yet).
As of today the subject belongs in the known unknown basket, IM(notvery)HO.

2
Antarctica / Re: January Poll 2019: JAXA Antarctic minimum
« on: January 16, 2019, 02:53:08 PM »
I bet the Antarctic Sea Ice Extent will just keep above 2 M km² (e.g. 2.08 M km²) but not go below it. According to the slower than average decline in the last week and the compactness of the remaining sea ice I wouldn't bet for the 1.875-2.125 M bin, so I chose the one above it (like Paddy did).
For those wondering about how much further melt will happen, attached is a graph of sea ice concentration derived from https://sites.google.com/site/arctischepinguin/home/sea-ice-extent-area/data

And postings by Tealight highlighted that the key is the Weddell sea so here is that graph as well

3
Antarctica / Re: Sea Ice Extent around Antarctica
« on: January 14, 2019, 11:46:39 AM »
JAXA ANTARCTIC Sea Ice Extent : 3,840,057 km2(January 13, 2019)

Extent loss of 84k , 58 k less than the average for this day.

Extent is lowest in the satellite record for this day, 110 k less than 2017 on this day, and 539 k km2 below 2018. Extent loss from maximum is 732k km2 (5.4%) greater than the 10 year average so far, with on average 84.4% of extent loss for the season done and on average 37 days to minimum.

The average remaining melt from this day to minimum would produce a minimum of 1.34 million km2,  810k km2 less than the record low in 2016-17.  Most of the remaining ice is at high concentration. With low concentration ice mostly gone the remaining solid ice close to the coast will likely continue to slow melt down further to a crawl.

Nevertheless, a record low minimum, the first below 2 million km2, is still my guess for the 2019 minimum, continuing the loss of Antarctic sea ice over the last three years (currently 3.8 million km2 less than the record high in 2014-15). However, the drop in daily extent losses has reduced confidence in that prediction.

All models have limitations. The first table attached shows that remaining melt in one of the previous years would result in an extent minimum of less than zero, an impossibility. Nevertheless, that is useful in that it shows how much extent this year is below that of the years to 2015.

Being still in the Austral summer, low extent and area means with insolation high, albedo warming potential in the Antarctic is also high and well above average.  This effect is gradually declining as 47 days of the highest insolation have now passed, and will quickly decline come February.

- see Tealight graphs at https://sites.google.com/site/cryospherecomputing/awp/antarctic-graphs

4
Arctic sea ice / Re: 2019 sea ice area and extent data
« on: January 14, 2019, 11:10:33 AM »
JAXA ARCTIC EXTENT 12,803,930 km2(January 13, 2019)

- Extent gain 37k, 3k more than average gain on this day.
- Extent is 4th lowest in the satellite record,
- Freezing to date from minimum is 147 k (1.8%) below the 10 year average extent gain,
- On average (last 10 years) 85.3 % of the increase in extent from min to max is done.

The outcome from using the 10 year average extent gain from now is a maximum of 14.18 million km2 (300k > 2018).

GFS indicates that overall the Arctic temperature varies from +1 to -1 degrees for the next week or more. This disguises the highly variable +ve and -ve anomalies at various times over the various regions of the Arctic. e.g. the Bering Sea looks like it will have strong +ve temp anomalies for some of the time interspersed with days of strong -ve anomalies.
______________________________________________________________________
ps: *The 2010's average figure I use in the attached table excludes 2019. I exclude 2019 (from all JAXA and NSIDC tables and graphs) so that the difference of the current year with the 2010's decade to date average is not modified by the current year data.
______________________________________________________________________

5
Arctic sea ice / Re: 2019 sea ice area and extent data
« on: January 13, 2019, 05:04:12 PM »
NSIDC Total Area as at 12 January 2019 (5 day trailing average) =  11,860,854 km2

Total Area         
 11,860,854    km2      
 229,478    km2   >    2010's average.
 473,845    k   >   2018
-233,106    k   <    2000's average.
         
Total Gain    17    k   
Peripheral Seas    10    k   gain
Central Seas__    3    k   gain
Other Seas___    4    k   gain
         
Peripheral Seas         
Bering _______    9    k   gain
Baffin  Bay____    7    k   gain
Greenland____   -1    k   loss
Barents ______   -5    k   loss
         
CAB Seas         
Beaufort_____   -0    k   loss
CAA_________    0    k   gain
East Siberian__   -4    k   loss
Central Arctic_   -4    k   loss
         
Kara_________    11    k   gain
Laptev_______    0    k   gain
Chukchi______   -0    k   loss
         
Other Seas         
Okhotsk______    6    k   gain
St Lawrence___   -0    k   loss
Hudson Bay___   -2    k   loss
Area gain 17k, 16 k below average for the day.

Other stuff

GFS indicates that overall the Arctic temperature varies from zero to -2 degrees for the next week or more. This disguises the highly variable +ve and -ve anomalies at various times over the various regions of the Arctic. e.g. the Bering Sea looks like it will have strong +ve temp anomalies for some of the time interspersed with days of strong -ve anomalies.

6
Arctic sea ice / Re: 2018 sea ice area and extent data
« on: January 12, 2019, 07:38:03 PM »
And here are the graphs for the total of the 14 Arctic Seas as provided by NSIDC.

Analysis - gradual movement towards ice-free.

7
Arctic sea ice / Re: 2018 sea ice area and extent data
« on: January 12, 2019, 06:49:48 PM »
GROUP 5 - "Non-Arctic Seas" - St Lawrence & Okhotsk (1.9 million Km2)
Longer-term trends


Ice-Free days. The measure I use for this is the number of days sea ice area is less than n% of the 1980's sea ice extent maximum, where n is <5% (= 95% or more ice-free), <15% (which for an NSIDC pixel = zero), and <50% (more than 50% means more ice than not).

The number of ice-free days on all the measures for the Okhotsk and for the 15% and 50% measures for the St Lawrence varies muchly from year to year. inserting a trend line makes it clear that there is an upward trend in ice-free days.

In contrast, the 5% (95 % ice free) measure for the St Lawrence is very stable from year to year. The reason for this difference from the 15% and 50% measure is a total mystery to me.

8
Arctic sea ice / Re: Global sea ice area and extent data
« on: January 10, 2019, 06:22:50 AM »
JAXA Global Sea Ice Extent as at 9 January 2019  17,027,437 km2

The continuing gradual reduction in daily Antarctic sea ice loss combined average to above average Arctic sea ice gain has resulted in Global Sea Ice Extent becoming 2nd lowest on the 4th Jan, and back to 1st lowest on the 5th by just 87k km2.

On average 37 days to minimum, with 78% of extent loss done, with an outcome from average remaining extent loss of a possible minimum of around 15 million km2, some 0.5 million km2 below the previous record low. BUT looking at the results from the previous 2 years, a more likely scenario, suggests a definite very low result, and maybe a 50-50 chance of a record low.

9
Arctic sea ice / Re: Global sea ice area and extent data
« on: January 09, 2019, 04:48:54 PM »
[ADS NIPR VISHOP (JAXA)] Global Sea Ice Extent.

January 8th, 2019:
     17,056,375 km2, a drop of -137,992 km2.
     2019 is the lowest on record.


We miss you Gerontocrat. Hope everything is fine!  ;)
Hi, Juan.

Computer & Mobile phone died.
Sticking plaster and soothing words applied.
Data rescue underway. (Amazingly, back-up system seems to have worked).

With luck back in action tomorrow.

What to do when this clapped out old laptop finally dies is a question I am avoiding.

10
Arctic sea ice / Re: 2019 sea ice area and extent data
« on: January 06, 2019, 02:43:47 PM »
NSIDC Total Area as at 5 January 2019 (5 day trailing average) =  11,590,404 km2

Total Area         
 11,590,404    km2      
 213,893    km2   >    2010's average.
 351,651    k   >   2018
-232,824    k   <    2000's average.
         
Total Gain    119    k   
Peripheral Seas    45    k   gain
Central Seas__    45    k   gain
Other Seas___    29    k   gain
         
Peripheral Seas         
Bering _______    14    k   gain
Baffin  Bay____    17    k   gain
Greenland____    3    k   gain
Barents ______    10    k   gain
         
CAB Seas         
Beaufort_____    1    k   gain
CAA_________    2    k   gain
East Siberian__    3    k   gain
Central Arctic_    8    k   gain
         
Kara_________    23    k   gain
Laptev_______    7    k   gain
Chukchi______   -0    k   loss
         
Other Seas         
Okhotsk______    17    k   gain
St Lawrence___    3    k   gain
Hudson Bay___    10    k   gain
Area gain of 119 k is above average by 78k on this day. That's a lot
Area is:
- 352k greater than 2018,
- 214k greater than the 2010's average,
- 233k less than the 2000's average.

Other stuff

GFS indicates that overall the Arctic temperature anomaly drops from +2 to zero by next Monday and perhaps averaging around -2 degrees to the 15th. . That is cold.

11
Arctic sea ice / Re: 2019 sea ice area and extent data
« on: January 06, 2019, 09:54:17 AM »
JAXA ARCTIC EXTENT 12,625,578 km2(January 5, 2019)

- Extent gain 35k, 9k below average (last 10 years) for the day.
- Extent is 8th lowest in the satellite record,
- Freezing to date from minimum is 41 k (0.5%) above the 10 year average extent gain,
- On average (last 10 years) 81.6 % of the increase in extent from min to max is done.

An extra line in the table attached based on average extent increase in the last 5 years has been added. This is because extent gain in 2012-13 was so large (rebound from record low minimum) that it distorts the average. The outcome from using the 10 year average extent gain from now is a maximum of 14.37 million km2 (490k > 2018).  Using the previous 5 years's average extent gain, the resulting maximum is 14.24 million km2, (360k > 2018).

GFS indicates that overall the Arctic temperature anomaly drops from +2 to zero by next Monday and perhaps averaging around -2 degrees to the 15th.
______________________________________________________________________
ps: *The 2010's average figure I use in the attached table excludes 2019. I exclude 2019 (from all JAXA and NSIDC tables and graphs) so that the difference of the current year with the 2010's decade to date average is not modified by the current year data.
______________________________________________________________________

12
Arctic sea ice / Re: 2019 sea ice area and extent data
« on: January 05, 2019, 11:08:43 AM »
JAXA ARCTIC EXTENT 12,590,152 km2(January 4, 2019)

- Extent gain 66k, 27k above average (last 10 years) for the day.
- Extent is 8th lowest in the satellite record,
- Freezing to date from minimum is 48 k (0.6%) above the 10 year average extent gain,
- On average (last 10 years) 81.2 % of the increase in extent from min to max is done.

An extra line in the table attached based on average extent increase in the last 5 years has been added. This is because extent gain in 2012-13 was so large (rebound from record low minimum) that it distorts the average. The outcome from using the 10 year average extent gain from now is a maximum of 14.38 million km2 (500k > 2018).  Using the previous 5 years's average extent gain, the resulting maximum is 14.24 million km2, (360k > 2018).

GFS indicates that overall the Arctic temperature anomaly drops from +3.5 to zero by next Monday and perhaps to -3.5 degrees by the 15th.
______________________________________________________________________
ps: *The 2010's average figure I use in the attached table excludes 2019. I exclude 2019 (from all JAXA and NSIDC tables and graphs) so that the difference of the current year with the 2010's decade to date average is not modified by the current year data.
______________________________________________________________________

13
Antarctica / Re: Sea Ice Extent around Antarctica
« on: January 04, 2019, 10:57:08 AM »
Here is a look at Sea Ice concentration in the record low year of 2017 and 2019 courtesy of University of Bremen.

As Tealight commented some time ago - the final minimum may well depend on the Weddell Sea - looking a bit more vulnerable this year.

14
Arctic sea ice / Re: 2018 sea ice area and extent data
« on: January 03, 2019, 09:56:02 PM »
The "pacific gateway" - the Bering and Chukchi Seas in 2018 - trends since 1979

The measure I used for this is the number of days sea ice area is less than n% of the 1980's sea ice extent maximum, where n is <5% (= 95% or more ice-free), <15% (which for an NSIDC pixel = zero), and <50% (more than 50% means more ice than not).

The three graphs attached show that in both seas there is a clear upward trend, but less pronounced for the <50% measure. Of note is that the Chukchi was never 95% ice-free until 2007.

15
Arctic sea ice / Re: 2018 sea ice area and extent data
« on: January 03, 2019, 07:55:30 PM »
A look at groups of seas.
First - The "pacific gateway" - the Bering and Chukchi Seas in 2018

The Bering Sea melted early and froze late. But then the December freeze was well above average. At the end of the year both extent and area were close to the March 2018 maximum. This is a reversal of recent year trends. Many of us were thinking that maybe the Bering had become a basically maritime climate sea that occasionally had some ice in it.

Apart from the late Feb to early March dip (the SSW event?)The Chukchi melt was pretty much average until late September. Then the melt season extended  to the second week in October followed by a rapid freeze.

The next post will look at long-term trends in these seas

16
Antarctica / Re: Sea Ice Extent around Antarctica
« on: January 03, 2019, 11:56:37 AM »
JAXA ANTARCTIC Sea Ice Extent - 5,115,518 km2(January 2, 2019)

Extent loss of 148k , 28 k less than the average for this day.

Extent is lowest in the satellite record for this day, 108 k less than 2016 on this day, and 1.075 million km2 below 2017. Extent loss from maximum is 1.138 million km2 (9.6%) greater than average so far, with on average 73.9% of extent loss for the season done and on average 48 days to minimum.

The average remaining melt from this day to minimum would produce a minimum of 0.94 million km2, 1.21 million km2 less than the record low in 2016-17.  A reducing proportion of the remaining ice is at low concentration. With that low concentration ice mostly gone the remaining solid ice close to the coast will likely slow melt down further to a crawl. Nevertheless, a record low minimum, the first below 2 million km2, is still my guess for the 2019 minimum, continuing the loss of Antarctic sea ice over the last three years.

All models have limitations. The first table attached shows that remaining melt in two of the previous years would result in an extent minimum of less than zero, an impossibility. Nevertheless, that is useful in that it shows how much extent this year is below that of the years to 2015.

Being in the Austral summer, low extent and area means with insolation high, albedo warming potential in the Antarctic is also high and well above average. - see Tealight graphs at https://sites.google.com/site/cryospherecomputing/awp/antarctic-graphs

17
Arctic sea ice / Re: 2019 sea ice area and extent data
« on: January 03, 2019, 11:08:25 AM »
JAXA ARCTIC EXTENT 12,454,828 km2(January 2, 2019)

- Extent gain 168k, 133k above average (last 10 years) for the day, the 5th day of very high and extremely high gains.
- Extent is 6th lowest in the satellite record,
- Freezing to date from minimum is just 2 k (0%) above the 10 year average extent gain,
- On average (last 10 years) 80.3 % of the increase in extent from min to max is done.

An extra line in the table attached based on average extent increase in the last 5 years has been added. This is because extent gain in 2012-13 was so large (rebound from record low minimum) that it distorts the average. The outcome from using the 10 year average extent gain from now is a maximum of 14.33 million km2 (450k > 2017).  Using the previous 5 years's average extent gain, the resulting maximum is 14.20 million km2, (320k > 2017).

GFS indicates that overall the Arctic temperature anomaly drop from +4.5 and to zero by next Monday and stay below zero for a few days after that. However, cold and warm pulses continue travelling up the Atlantic Front to north of Novaya Zemla.
______________________________________________________________________
ps: *The 2010's average figure I use in the attached table excludes 2018. I exclude 2018 (from all JAXA and NSIDC tables and graphs) so that the difference of the current year with the 2010's decade to date average is not modified by the current year data.
______________________________________________________________________

18
Arctic sea ice / Re: 2018 sea ice area and extent data
« on: January 02, 2019, 10:42:20 PM »
2018 has been 'n gone.
What happened?

An occasional series of graphs commences.

Attached are the total arctic area and extent graphs for 2018. They do show the low max last March and the slow freeze in late sept /oct. They also conceal the great variation in individual Arctic Seas.

19
Consequences / Re: Water wars
« on: January 02, 2019, 09:05:23 PM »
Jordan and the Middle East.

The Dead Sea is dropping by about 1.2 metres a year, mostly due to the over extraction of water from the River Jordan (often now just a series of muddy puddles) and over extraction from aquifers in Jordan and by its neighbours. Just another indication of  the perennial problem of water demand greater than water supply that plagues all of the Middle East.

When I was there in 2003 and 2004 there was a lot of discussion about how much was down to bad agriculture. Instead of crops suitable for semi-desert, (e.g. olives) - banana plantations everywhere.  But these estates were owned by powerful families - nothing could or can be done.

I produced a business plan for the water and waste water for the Northern Governorates of Jordan. Much of the plan was about reducing water losses, thereby delaying the inevitable. But agriculture use was inviolate. As part of the research for the plan I also looked at water resources and water use in the entire region - Iraq, Israel, Syria, part of Turkey, Saudi Arabia. It was not good.

The only surprise about Jordan now going for the DISI aquifer water is that it has taken so long.
Other Middle East countries increasingly rely on desalination - but that can only take you so far, and even reverse osmosis is not cheap in cost or energy. News from Iran on water and agriculture is not good. In a few years demand for oil and gas will reduce as the water resources gap yawns wider and wider. The only question is - when. Climate change? Just nudges things along a bit quicker. There is a horrible inevitability about it all.


20
Arctic sea ice / Re: 2019 sea ice area and extent data
« on: January 02, 2019, 03:11:51 PM »
NSIDC Total Area as at 1 January 2019 (5 day trailing average) = 11,113,007 km2

Total Area         
 11,113,007    km2      
-69,723    km2   <    2010's average.
 215,003    k   >   2017
-499,530    k   <    2000's average.
         
Total Gain    89    k   
Peripheral Seas    45    k   gain
Central Seas__    18    k   gain
Other Seas___    26    k   gain
         
Peripheral Seas         
Bering _______    9    k   gain
Baffin  Bay____    16    k   gain
Greenland____    10    k   gain
Barents ______    11    k   gain
         
CAB Seas         
Beaufort_____    4    k   gain
CAA_________   -1    k   loss
East Siberian__   -1    k   loss
Central Arctic_    10    k   gain
         
Kara_________    7    k   gain
Laptev_______   -1    k   loss
Chukchi______    1    k   gain
         
Other Seas         
Okhotsk______    8    k   gain
St Lawrence___    3    k   gain
Hudson Bay___    15    k   gain
Area gain of 89 k is below average by 28k on this day.
Area is:
- 215k greater than 2017,
- 70k less than the 2010's average,
- 500k less than the 2000's average.

Area gain switched from back to above average to low.

Other stuff
GFS indicates that overall the Arctic temperature anomaly drop from +4.5 and to zero by next Monday and stay below zero for a few days after that. However, cold and warm pulses continue travelling up the Atlantic Front to north of Novaya Zemla.

Regional variations suggest that while the main Arctic freezes solid and the Bering quickly increases in ice area and extent, the Atlantic Front may still resist icing up part of the time.

21
Antarctica / Re: Sea Ice Extent around Antarctica
« on: January 01, 2019, 03:24:12 PM »
Thanks Sleepy - I've saved that.
Two opposing forces
- increased cold fresh water from increased melt of the AIS and shelves,
- increased ocean warmth (e.g. Tealight's AWP graphs) and atmospheric warmth.
and
- Loads more energy and water vapour in the system.
- so increased mass from loads more snowfall, and loads more melt at the surface and below.

The sleeping giant of Antarctica awakes?

meanwhile.....

JAXA ANTARCTIC Sea Ice Extent - 5,423,435 km2(December 31, 2018)

Extent loss of 194k , 13 k more than the average for this day. The loss is again more than that on this day in 2016, the year of the record low minimum.

Extent is lowest in the satellite record for this day, 134 k less than 2016 on this day, and 1.065 million km2 below 2017. Extent loss from maximum is 1.108 million km2 (10.3%) greater than average so far, with on average 71.7% of extent loss for the season done and on average 50 days to minimum.

The average remaining melt from this day to minimum would produce a minimum of 0.89 million km2, 1.26 million km2 less than the record low in 2016-17.(Note that a minor correction to the spreadsheet made -change of year glitch).  A reducing proportion of the remaining ice is at low concentration. With that low concentration ice mostly gone the remaining solid ice close to the coast will likely slow melt down further to a crawl. Nevertheless, a record low minimum, the first below 2 million km2, is still my guess for the 2019 minimum, continuing the loss of Antarctic sea ice over the last three years.

All models have limitations. The first table attached shows that remaining melt in two of the previous years would result in an extent minimum of less than zero, an impossibility. Nevertheless, that is useful in that it shows how much extent this year is below that of the years to 2015.

Being in the Austral summer, low extent and area means with insolation high, albedo warming potential in the Antarctic is also high and well above average. - see Tealight graphs at https://sites.google.com/site/cryospherecomputing/awp/antarctic-graphs
 

22
Arctic sea ice / Re: Poll: year-end JAXA extent ranking
« on: January 01, 2019, 12:53:36 PM »
31st Dec 2018 extent was at position No 3 -  12,164,925 km2.

It would have been 2nd but for extent gain of 293 k in the last 3 days, twice the average.

23
Arctic sea ice / Re: 2018 sea ice area and extent data
« on: December 31, 2018, 02:37:28 PM »
NSIDC Total Area as at 30 December (5 day trailing average) = 10,969,557 km2

Total Area         
 10,969,557    km2      
-94,823    km2   <    2010's average.
 168,884    k   >   2017
-549,994    k   <    2000's average.
         
Total Gain    42    k   
Peripheral Seas    24    k   gain
Central Seas__    0    k   gain
Other Seas___    18    k   gain
         
Peripheral Seas         
Bering _______    10    k   gain
Baffin  Bay____    6    k   gain
Greenland____    3    k   gain
Barents ______    5    k   gain
         
CAB Seas         
Beaufort_____   -2    k   loss
CAA_________   -2    k   loss
East Siberian__   -5    k   loss
Central Arctic_    7    k   gain
         
Kara_________   -1    k   loss
Laptev_______   -3    k   loss
Chukchi______    4    k   gain
         
Other Seas         
Okhotsk______    5    k   gain
St Lawrence___    0    k   gain
Hudson Bay___    12    k   gain
Area gain of 42 k is below average by 16k on this day.
Area is:
- 169k greater than 2017,
- 95k less than the 2010's average,
- 550k less than the 2000's average.

Area gain switched from well above average to low in the last 6 days, mostly due to area losses in the Baffin, Kara and Laptev seas, which are now about over..

Other stuff
GFS indicates that overall the Arctic temperature anomaly will be between +3.5 and +4 for the next 3 days and reduce to zero by a few days after that. However, cold and warm pulses continue travelling up the Atlantic Front to north of Novaya Zemla.

Regional variations suggest that while the main Arctic freezes solid and the Bering quickly increases in ice area and extent, the Atlantic Front may still resist icing up.
[/quote]

25
Arctic sea ice / Re: 2018 sea ice area and extent data
« on: December 28, 2018, 02:10:23 PM »
NSIDC Total Area as at 27 December (5 day trailing average) =   10,884,652 km2

I did not expect to see a -ve daily area gain - even if only 136 km2
Total Area         
 10,884,652    km2      
-15,932    km2   <    2010's average.
 219,598    k   >   2017
-516,244    k   <    2000's average.
         
Total Gain   -0    k   
Peripheral Seas    6    k   gain
Central Seas__   -23    k   loss
Other Seas___    17    k   gain
         
Peripheral Seas         
Bering _______    6    k   gain
Baffin  Bay____   -11    k   loss
Greenland____    7    k   gain
Barents ______    5    k   gain
         
CAB Seas         
Beaufort_____   -6    k   loss
CAA_________   -0    k   loss
East Siberian__   -1    k   loss
Central Arctic_    7    k   gain
         
Kara_________   -15    k   loss
Laptev_______   -6    k   loss
Chukchi______   -1    k   loss
         
Other Seas         
Okhotsk______    7    k   gain
St Lawrence___   -1    k   loss
Hudson Bay___    11    k   gain
Area gain of 0 k is below average by 35k on this day.
Area is:
- 220k greater than 2017,
- 16k less than the 2010's average,
- 516k less than the 2000's average.

Area gain switched from well above average to zero in the last 3 days, mostly due to area losses in the Kara and Laptev seas.

Other stuff
GFS indicates that overall the Arctic temperature anomaly will be between +1.5 and +3 for the next week or so.

Regional variations suggest that while the main Arctic freezes solid and the Bering quickly increases in ice area and extent, the Atlantic Front may still resist icing up.

26
Antarctica / Re: Sea Ice Extent around Antarctica
« on: December 28, 2018, 09:57:11 AM »

I think the main limitation of the model is not separating the Antarctic sea ice into its constituent regions.

In the Antarctic, due to having a continent in the middle, the interaction between the various regions in summer is minimal to nonexistent. So it pays off looking at the various regions as separate entities. Such an analysis (I am using AMSR2 area but I expect other metrics to behave similarly) reveals the fact that this year is leading mostly in the Ross Sea sector - the same one that went to almost zero in the past two winters (Feb 2018 and Feb 2017). The Ross Sea is what generates the negative result, as its normal losses are simply higher than the current extent. This is obviously not going to happen, and although an early and complete melt-out of the Ross Sea may have some serious implications, a record sea ice minimum is not necessarily one of them.
In the largest and most difficult to melt sector, the Weddel Sea, this year follows the previous two years to the letter and can reasonably be expected to bottom at the same low level by mid-Feb 2019.
All in all, I'm not sure if the expectation of a new record is justified, though it's certainly possible. At least one sector will have to break past limitations for that to happen.

I wish that Antarctic Sea Ice extent and area was easily downloadable from somewhere as .csv or excel files as for the Arctic extent and area from JAXA and NSIDC. Is it?

You may well be right about the resistance of the Weddell Sea - as was also pointed out by Tealight. BUT - the attached image suggests that the Weddell Sea Ice is looking a bit more vulnerable than it did in 2016. So I am sticking with my guess at a likely minimum below 2 million km2, but nowhere near that produced by the spreadsheet. After all that only needs a minimum of 150 k less than in 2016-17.

There is one question for which I have not seen a good answer. Why has this sudden loss of Antarctic Sea ice over the last 3 years happened?

27
Antarctica / Re: Sea Ice Extent around Antarctica
« on: December 28, 2018, 09:44:11 AM »
JAXA ANTARCTIC Sea Ice Extent - 6,065,577 km2(December 27, 2018)

Extent loss of 194k , 18k less than average on this day. The first time below average for a long time. However, the loss is more than that on this day in 2016 and 2017, the years of record low minima.

Extent is 2nd lowest, at a reducing 77 k greater than 2016 on this day, and 1,068 million km2 below 2017. Extent loss from maximum is 1.352 million km2 (12.6%) greater than average so far, with on average 67.3% of extent loss for the season done and on average 54 days to minimum.

The average remaining melt from this day to minimum would produce a minimum of 0.86 million km2,  1.29 million km2 less than the record low in 2016-17. A good proportion of the remaining ice is at low concentration compared with 2016 (see next post) adding to the chances of a record low extent. However, when that low concentration ice is gone the solid land fast ice on the coast will likely slow down further melt to a crawl. Nevertheless, a record low minimum, the first below 2 million km2, is still my guess for the 2019 minimum, continuing the loss of Antarctic sea ice over the last three years.

All models have limitations. The first table attached shows that remaining melt in three of the previous years would result in an extent minimum of less than zero, an impossibility. Nevertheless, that is useful in that it shows how much extent this year is below that of the years to 2015.

Being in the Austral summer, low extent and area means with insolation high, albedo warming potential in the Antarctic is also high and well above average.

- see Tealight graphs at https://sites.google.com/site/cryospherecomputing/awp/antarctic-graphs

28
Arctic sea ice / Re: 2018 sea ice area and extent data
« on: December 28, 2018, 08:40:33 AM »
JAXA ARCTIC EXTENT 11,846,140 km2(December 27, 2018)

- Extent gain 3k, 50k below average (last 10 years) for the day,
- Extent is 3rd lowest in the satellite record,
- Freezing to date from minimum is 350 k (4.5%) below the 10 year average extent gain,
- On average (last 10 years) 77.7 % of the increase in extent from min to max is done.

An extra line in the table attached based on average extent increase in the last 5 years has been added. This is because extent gain in 2012-13 was so large (rebound from record low minimum) that it distorts the average. The outcome from using the 10 year average extent gain from now is a maximum of 13.98 million km2 (100k > 2017).  Using the previous 5 years's average extent gain, the resulting maximum is 13.81 million km2, (70k < 2017).

Extent gain from minimum on this day greatly below average. On average (last 10 years) three quarters of extent gain from min to max is now done with on average 74 days to maximum.

GFS indicates that overall the Arctic temperature anomaly will be between +1.5 and +3 for the next week or so.
______________________________________________________________________
ps: *The 2010's average figure I use in the attached table excludes 2018. I exclude 2018 (from all JAXA and NSIDC tables and graphs) so that the difference of the current year with the 2010's decade to date average is not modified by the current year data.
______________________________________________________________________
[/quote]

29
Antarctica / Re: Sea Ice Extent around Antarctica
« on: December 27, 2018, 09:02:36 AM »
The first image shows the vulnerability of the remaining ice to melt compared with 2016.

The second is a gif showing the melt over the last few days.

30
Consequences / Re: Pathogens and their impacts
« on: December 26, 2018, 03:34:53 PM »
I sent an e-mail to NIPR about the JAXA data. I got a nice reply.
(https://forum.arctic-sea-ice.net/index.php/topic,2223.msg185174.html#msg185174)

So I have sent them a thankyou email and mentioned how this forum uses and values the sea ice data from the NIPR / JAXA organisation. I also gave them the link to this forum.

Trouble is, if they use it what might they see on the unread posts page and what might they read if following the obvious link? Conspiracy theories from the lunatic asylum. Bloody embarassing.

and that's all I'm going to say about that


31
Arctic sea ice / Re: 2018 sea ice area and extent data
« on: December 26, 2018, 10:33:26 AM »
JAXA SIE data for December 16 and 17 has been revised.
Aha!

32
Antarctica / Re: Sea Ice Extent around Antarctica
« on: December 25, 2018, 10:51:58 AM »
JAXA ANTARCTIC Sea Ice Extent - 6,775,143 km2(December 24, 2018)

continues to drop like a rock.

Merry Xmas

33
Antarctica / Re: Sea Ice Extent around Antarctica
« on: December 24, 2018, 09:19:40 AM »
JAXA ANTARCTIC Sea Ice Extent - 7,078,498 km2(December 23, 2018)

Extent loss of 326k , 118k greater than average on this day.

Extent is 2nd lowest, though still at (a quickly reducing) 377 k greater than 2016 on this day, but 755 k below 2017. Extent loss from maximum is 1.23 million km2 (12.6%) greater than average so far, with on average 61.6% of extent loss for the season done and 58 days to minimum (compared with  last 10 years average).

A record low minimum is a real possibility, making 3 years in a row, and the first below 2 million km2. Indeed,  the average remaining melt from this day to minimum would produce a minimum of 0.97 million km2, nearly 1.2 million km2 less than the record low in 2016-17. This result is hard to believe.

All models have limitations. The first table attached shows that remaining melt in two of the previous years would result in an extent minimum of less than zero, an impossibility. Nevertheless, that is useful in that it shows how much extent this year is below that of the years to 2015.

Most of the remaining ice is at low concentration, adding to the chances of a record low extent. Being in the Austral summer, low extent and area means with insolation high, albedo warming potential in the Antarctic is also high and well above average.

- see Tealight graphs at https://sites.google.com/site/cryospherecomputing/awp/antarctic-graphs

34
Antarctica / Re: Sea Ice Extent around Antarctica
« on: December 23, 2018, 01:32:29 PM »
JAXA ANTARCTIC Sea Ice Extent - 7,404,381 km2(December 22, 2018)

Extent loss of 289k , 66k greater than average on this day.

Extent is 2nd lowest, though still at (a quickly reducing) 0.52 million km2 greater than 2016 on this day, but  598 k below 2017. Extent loss from maximum is 1.12 million km2 (11.7%) greater than average so far, with on average 60.3% of extent loss for the season done and 59 days to minimum (compared with  last 10 years average).

A record low minimum is a real possibility, making 3 years in a row, and the first below 2 million km2. Indeed,  the average remaining melt from this day to minimum would produce a minimum of 1.09 million km2, 1 million km2 less than the record low in 2016-17. This result is hard to believe.

All models have limitations. The first table attached shows that remaining melt in two of the previous years would result in an extent minimum of less than zero, an impossibility. Nevertheless, that is useful in that it shows how much extent this year is below that of the years to 2015.

Most of the remaining ice is at low concentration, adding to the chances of a record low extent. Being in the Austral summer, low extent and area means with insolation high, albedo warming potential in the Antarctic is also high and well above average.

- see Tealight graphs at https://sites.google.com/site/cryospherecomputing/awp/antarctic-graphs

35
Science / Re: Solar cycle
« on: December 21, 2018, 10:33:59 AM »
'Tis the solstice.

Winter Solstice 2018 will be at 22:23 hrs Greenwich mean Time (GMT) on Friday, 21 December.

This is the solar cycle that interests me most, apart from the butterfly wings image of the sunspot cycles.

Imagine it is pre-history, and you do not know if this year the sun will start to rise higher in the sky again. Perhaps this time it will get lower and lower in the sky until......


36
Policy and solutions / Re: Oil and Gas Issues
« on: December 17, 2018, 08:57:06 AM »
A bit of hopeful news for a change.
 
https://www.theguardian.com/commentisfree/2018/dec/16/divestment-fossil-fuel-industry-trillions-dollars-investments-carbon

At last, divestment is hitting the fossil fuel industry where it hurts
Bill McKibben

Quote
Trillions of dollars of investments are being taken out of carbon-intensive companies. Governments must now take notice

......we have marked the 1,000th divestment in what has become by far the largest anti-corporate campaign of its kind. The latest to sell their shares – major French and Australian pension funds, and Brandeis University in Massachusetts – bring the total size of portfolios and endowments in the campaign to just under $8 trillion (£6.4tn).....

.....since the fossil fuel sector has badly underperformed on the market over recent years, moving money into other investments has dramatically increased returns. Pity, for instance, the New York state comptroller Thomas DeNapoli – unlike his New York City counterpart, he refused to divest, and the cost has been about $17,000 per pensioner.......

At first we thought our biggest effect would be to rob fossil fuel companies of their social licence. Since their political lobbying power is above all what prevents governments taking serious action on global warming, that would have been worth the fight........As time went on it became clear that divestment was also squeezing the industry.......Indeed, just a few weeks ago analysts at that radical collective Goldman Sachs said the “divestment movement has been a key driver of the coal sector’s 60% de-rating over the past five years”.

Now the contagion seems to be spreading to the oil and gas sector, where Shell announced earlier this year that divestment should be considered a “material risk” to its business. That’s how oil companies across the world are treating it – in the US, petroleum producers have set up a website designed to discredit divestment...

37
Antarctica / Re: Sea Ice Extent around Antarctica
« on: December 16, 2018, 05:18:49 PM »
And the result can be seen in Tealight's Albedo graphs at https://sites.google.com/site/cryospherecomputing/awp/antarctic-graphs

Note how daily AWP is nearly at 2016 levels even though extent is still 1.5 million km2 above 2016 levels. Cumulative AWP is well behind 2016 due to the slow start of the Antarctic melting season.

The last graph shows where the melting is happening - and where it is not.

38
Antarctica / Re: Sea Ice Extent around Antarctica
« on: December 16, 2018, 12:23:21 PM »
JAXA ANTARCTIC Sea Ice Extent - 9,816,575 km2(December 14, 2018)

Extent loss of 273k , 60k greater than average on this day.

Extent is 2nd lowest, though still 1.50 million km2 greater than 2016 on this day, and just 12 k below 2017. Extent loss from maximum is 519k (6.4%) greater than average so far, with on average 50.6% of extent loss for the season done and just 66 days to minimum (compared with  last 10 years average).

A record low minimum is a real possibility, making 3 years in a row, and the first below 2 million km2. So much for increased Antarctic Ice Sheet melt causing increased sea ice extent.

Being at the beginning of the Austral summer, low extent and area means once again with insolation high, albedo warming potential in the Antarctic is also high and well above average.

- see Tealight graphs at https://sites.google.com/site/cryospherecomputing/awp/antarctic-graphs
[/quote]

39
Arctic sea ice / Re: What's new in the Arctic ?
« on: December 14, 2018, 01:13:26 PM »
A new article in the Scientific American is quite good, covering a lot of what has been happening in the Arctic:

The article is from April 1st.

Jennifer Francis in American Scientist is quite the American Alarmist.

First of all, it's Scientific American. Second, if you think that a scientist who tries to make sense of the consequences that rapid Arctic sea ice loss will inevitably have, nay, is already having, is 'alarmist', you're in the wrong forum.
She is one of a rare species, a damn good scientist willing to challenge conventional wisdom, and a damn good communicator.

40
Arctic sea ice / Re: 2018 sea ice area and extent data
« on: December 12, 2018, 02:37:03 PM »
Quote from my last post
Quote
Increase in area gain still mainly driven by Hudson Bay (+35k on this day) and Chukchi (+25k). But this is self-limiting as at this rate of gain Hudson Bay Bay will be full-up ice in less than 5 days, and the Chukchi a few days after.

Hudson Extent is almost at maximum, just 2 days to go?
Chukchi Extent just 100k below maximum - 4 days to go?

(In the freezing season, area gain tends to be a lagging indicator of the re-freeze)

41
Arctic sea ice / Re: 2018 sea ice area and extent data
« on: December 11, 2018, 02:31:08 PM »
NSIDC Total Area as at 10 December (5 day trailing average) = 9,969,673 km2
Total Area         
 9,969,673    km2      
 65,050    km2   >    2010's average.
 376,092    k   >   2017
-388,039    k   <    2000's average.

Total Gain    92    k   
Peripheral Seas    28    k   gain
Central Seas__    18    k   gain
Other Seas___    46    k   gain
         
Peripheral Seas         
Bering _______    3    k   gain
Baffin  Bay____    13    k   gain
Greenland____    13    k   gain
Barents ______   -2    k   loss
         
CAB Seas         
Beaufort_____    4    k   gain
CAA_________   -4    k   loss
East Siberian__    5    k   gain
Central Arctic_   -4    k   loss
         
Kara_________   -8    k   loss
Laptev_______   -1    k   loss
Chukchi______    26    k   gain
         
Other Seas         
Okhotsk______   -1    k   loss
St Lawrence___    1    k   gain
Hudson Bay___    46    k   gain
Area gain above average (by 15k) and increasing day by day.
Area now retreating from the approach to the 2000's average, and close to 2010's average.
This is in line with recent very slow gains (and even extent loss) in daily extent (both JAXA and NSIDC data) which is now changing to increasing extent gain.

Other stuff
GFS indicates that overall the Arctic is at a temperature anomaly of around +3.5 to +4 celsius  for the next four days then quickly goes down to about +1. BUT, the strong +ve anomalies on the Atlantic Front persist . In contrast, small -ve anomalies in the Bering and Okhotsk for the next few days.

GFS still saying another pulse of warmer air moving West to East across N. America greatly reducing extreme cold in Central and NE Canada over the next few days or even longer.
Okhotsk, Bering and Chukchi areas are well below zero, and no major pulses of warmth on the horizon. Result is showing in the Chukchi area gains, but not yet elsewhere.

As fierce +ve temp anomaly over the Atlantic front looks like continuing for a good few days more, either losses on the Atlantic front will continue, or gains will be low, until the weather pattern changes. Kara Sea area loss lower on this day at 8 k. Also Central Arctic Sea losses continuing, but also reducing.

Increase in area gain still mainly driven by Hudson Bay (+46k on this day) and Chukchi (+26k). But this is self-limiting as at this rate of gain Hudson Bay Bay will be full-up ice in less than 5 days, and the Chukchi a few days after.

42
Antarctica / Re: What's new in Antarctica ?
« on: December 11, 2018, 12:12:52 PM »
Bronselaer et al. report on effect of increase ice melt from AIS on climate:

"Meltwater causes a reduction  in global atmospheric warming, delaying the realization of 1.5 °C and 2 °C warming by more than ten years; it drives a northward shift of the ITCZ, which results in reduced drying over Northern Hemisphere landmasses and enhanced drying in the Southern Hemisphere; and  it causes a large (up to 31%) increase in Antarctic sea-ice formation
sidd

All the scientists say increased melt from the AIS will cause / is causing an increase in Antarctic sea ice extent. Up to 2014 the data supported this. Since then the data does not. I posted this on the Antarctic Sea Ice extent thread. At this moment in time the sea ice in Antarctic is falling to bits.

Quote from: AbruptSLR

Quote
This defined layering of temperatures is exactly what is happening now around the Antarctic.

"The reason for the layering is that global warming in parts of Antarctica is causing land-based ice to melt, adding massive amounts of freshwater to the ocean surface," said ARC Centre of Excellence for Climate System Science researcher Prof Matthew England an author of the paper.
"At the same time as the surface is cooling, the deeper ocean is warming, which has already accelerated the decline of glaciers on Pine Island and Totten. It appears global warming is replicating conditions that, in the past, triggered significant shifts in the stability of the Antarctic ice sheet.""

There is a consistent narrative -

AGW is causing land-based ice to melt faster, adding massive additional amounts of freshwater to the ocean surface.

You would think that cold surface water (also low salinity with a higher freezing temperature) would encourage sea ice freeze as winter approaches and discourage sea ice melt as summer commences. Since 1979 up to recently, there has been a slow but measurable increase in Antarctic sea ice extent (maximum extent in 2014). Hypothesis confirmed ?

BUT since then the opposite. Antarctic sea ice extent is in decline, not just at max and min but during the melt season. Temporary aberration? Or is something  extra going on?


ps :Found this post from Jim Pettit on an old Antarctic Thread

https://forum.arctic-sea-ice.net/index.php/topic,178.msg2754.html#msg2754

Quote
New paper explains the recent growth of Antarctic sea ice.
« on: March 31, 2013, 10:20:40 PM »

Nature Geoscience published a new study online today that I found very interesting. It sheds some more light on the reasons behind the seemingly paradoxical growth of Antarctic sea ice (Important role for ocean warming and increased ice-shelf melt in Antarctic sea-ice expansion) From the abstract:

"Changes in sea ice significantly modulate climate change because of its high reflective and strong insulating nature. In contrast to Arctic sea ice, sea ice surrounding Antarctica has expanded, with record extent in 2010. This ice expansion has previously been attributed to dynamical atmospheric changes that induce atmospheric cooling. Here we show that accelerated basal melting of Antarctic ice shelves is likely to have contributed significantly to sea-ice expansion. Specifically, we present observations indicating that melt water from Antarctica’s ice shelves accumulates in a cool and fresh surface layer that shields the surface ocean from the warmer deeper waters that are melting the ice shelves. Simulating these processes in a coupled climate model we find that cool and fresh surface water from ice-shelf melt indeed leads to expanding sea ice in austral autumn and winter. This powerful negative feedback counteracts Southern Hemispheric atmospheric warming. Although changes in atmospheric dynamics most likely govern regional sea-ice trends, our analyses indicate that the overall sea-ice trend is dominated by increased ice-shelf melt. We suggest that cool sea surface temperatures around Antarctica could offset projected snowfall increases in Antarctica, with implications for estimates of future sea-level rise.

43
Antarctica / Re: Sea Ice Extent around Antarctica
« on: December 11, 2018, 11:48:11 AM »
Antarctic Sea Ice Area & Compaction went into freefall in early December. Sea Ice Area is now just above 2016. Judging from the compaction graph, the extent cliff should soon follow and be at least as impressive as the area cliff.

Tealight's prediction continues to be spot on

JAXA ANTARCTIC Sea Ice Extent - 10,981,865 km2(December 10, 2018)

A drop of 338k , 107k greater than average on this day. Though not a rarity at this time of year, 2 days above 300k in a row is more uncommon. Extent is 3rd lowest, though still 1.6 million km2 greater than 2016 on this day, but only 135k above 2017. Extent loss from maximum is very close to average so far, with on average 78.6% of extent loss for the season done and just 71 days to minimum.

A record low minimum is a real possibility.

Being at the beginning of the Austral summer, low extent and area means once again with insolation high, albedo warming potential in the Antarctic is also high and well above average. Will this acceleration in extent and area loss still continue ?

44
Arctic sea ice / Re: Poll: year-end JAXA extent ranking
« on: December 11, 2018, 11:19:09 AM »
With 21 days to go, this is what Dec 31 extent is looking like at the moment, based on previous years' extent gains.

45
Arctic sea ice / Re: 2018 sea ice area and extent data
« on: December 11, 2018, 11:15:02 AM »
JAXA ARCTIC EXTENT 11,073,503 km2(December 10, 2018)

- Extent gain at 110 k is  average gain (2008-2017) for this day,
- Extent is 3rd lowest in the satellite record, see Juan's post above for details (and attached table).
- Freezing to date from minimum is 219 k (3.2%) LESS than the 10 year average extent gain,
- On average (last 10 years) 68.6 % of the increase in extent from min to max is done.

An extra line in the table based on average extent increase in the last 5 years has been added. This is because extent gain in 2012-13 was so large (rebound from record low minimum) that it distorts the average. The outcome from using the 10 year average extent gain from now is a maximum of 14.11 million km2 (230k > 2017).  Using the previous 5 years's average extent gain, the resulting maximum is 13.97 million km2, (80k > 2017).

Extent gain from minimum on this day a little below average. On average (last 10 years)  over 2/3rds of extent gain from min to max is now done with on average 91 days to maximum.

GFS indicates that overall the Arctic is at a temperature anomaly of around +3.5 to +4 celsius  for the next four days then quickly goes down to about +1. BUT, the strong +ve anomalies on the Atlantic Front persist . In contrast, small -ve anomalies in the Bering and Okhotsk for the next few days.
______________________________________________________________________
ps: *The 2010's average figure I use in the attached table excludes 2018. I exclude 2018 (from all JAXA and NSIDC tables and graphs) so that the difference of the current year with the 2010's decade to date average is not modified by the current year data.
______________________________________________________________________

46
Arctic sea ice / Re: 2018 sea ice area and extent data
« on: December 10, 2018, 01:54:51 PM »
Gerontocrat, I take the GFS forecasts from here
It shows anomalies of about 1.5-2 K, with tendency of getting lower.

I only look as far as 5 days ahead. GFS does say after that the anomaly gets much lower, to below +1.5. But GFS tends to be very wobbly that far out. Many contributors to this forum have warned about looking at any of the forecast models beyond 5 days. Chaos theory was invented(?) developed(?) by meteorologists.

47
Arctic sea ice / Re: 2018 sea ice area and extent data
« on: December 10, 2018, 09:40:59 AM »
JAXA ARCTIC EXTENT 10,963,122 km2(December 9, 2018)

- Extent gain at 82 k is 7 k below the average gain (2008-2017) on this day,
- Extent is 3rd lowest in the satellite record, see Juan's post above for details (and attached table).
- Freezing to date from minimum is 219 k (3.2%) LESS than the 10 year average extent gain,
- On average (last 10 years) 67.5 % of the increase in extent from min to max is done.

An extra line in the table based on average extent increase in the last 5 years has been added. This is because extent gain in 2012-13 was so large (rebound from record low minimum) that it distorts the average. The outcome from using the 10 year average extent gain from now is a maximum of 14.11 million km2 (230k > 2017).  Using the previous 5 years's average extent gain, the resulting maximum is 13.96 million km2, (80k > 2017).

Extent gain from minimum on this day a little below average. Is the period of well below average gain ending as the freeze takes hold in the peripheral seas?

On average (last 10 years) just over 2/3rds of extent gain from min to max is now done with on average 92 days to maximum.

GFS indicates that overall the Arctic is at a temperature anomaly of around +3.5 to +4 celsius  for the next few days.
______________________________________________________________________
ps: *The 2010's average figure I use in the attached table excludes 2018. I exclude 2018 (from all JAXA and NSIDC tables and graphs) so that the difference of the current year with the 2010's decade to date average is not modified by the current year data.
______________________________________________________________________
[/quote]

48
Arctic sea ice / Re: The 2018/2019 freezing season
« on: December 09, 2018, 09:15:54 AM »
December 3-8.
With the Kara continuing to be blown back, seemingly the same wind regime has been pushing Chukchi ice into growth mode, and CAB ice into Fram export, thus achieving slightly above average growth.
I repeat my prediction that once the Kara process revereses, as it evntually will, we will see oversized extent gains - at least for a few days.
"With the Kara continuing to be blown back". If it was only wind causing the ice front to retreat, surely one would see greater compaction. Looking at Aluminium's gif, there are signs of reduced compaction. Perhaps ocean heat transport is also having an effect (i.e. some of the extent loss is actually melt) ?

Mind you, that still means when the weather pattern changes there will be rapid extent gains. That weather pattern still looks like hanging on for a few more days.

49
Arctic sea ice / Re: When will the Arctic Go Ice Free?
« on: December 08, 2018, 09:04:15 PM »
Maybe the "stall" is a statistical construct. Or maybe (a heresy to say on this site it seems) after the periphery melt out relatively quickly, the Central Arctic has different characteristics and will be a much harder nut to crack. In my opinion the "stall" is due to that the "easy" ice is gone and it is more difficult to melt the central parts. That is why you can not extrapolate from the past few years. The Central Arctic will be gone for (almost) sure but it is hard to model when in my view. Let me attach a picture how I see this whole process...

There is a new paper that I think supports your contention. Basically it says that increased ocean heat transport (OHT) affects the Arctic seas over the continental shelves while it is the atmosphere that drives SIE in  the central arctic (over the deep ocean). (I can't access the full paper)

https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2018JC014525
The role of ocean heat transport in rapid sea ice declines in the Community Earth System Model Large Ensemble
Quote
Abstract
Many climate models, including the the Community Earth System Model Large Ensemble (CESM‐LE), predict future rapid sea ice declines in the Arctic linked with anomalous northward Ocean Heat Transport (OHT). Using CESM‐LE, we find that the partitioning of the poleward OHT between the different Arctic gates (Barents Sea Opening (BSO), Bering Strait and Fram Strait) is key to this link with the rapid declines. 64 of the 79 rapid declines in CESM‐LE are correlated with the anomalous OHT through one of the gates. Rapid declines that happen earlier in the simulations when the sea ice covers the continental shelves are correlated with anomalous OHT. The interaction between OHT and sea ice happens mainly over continental shelves since most rapid declines are correlated with the BSO or Bering Strait OHTs and only a few with the Fram Strait OHT (often also correlated with BSO or Bering Strait OHTs). In most rapid rapid declines not correlated with OHT, the September Sea Ice Extent (SIE) prior to the decline is smaller than the area covered by the deep basins. Those are associated with surface heat flux since the ice‐atmosphere heat fluxes are more strongly correlated with the sea ice concentrations over the deep basins than the ice‐ocean heat fluxes. Our results suggest that OHTs are causing rapid sea ice declines when the SIE is large enough to cover the continental shelves and that the atmosphere is the main driver when the initial SIE is located only over the deep basins.

Plain Language Summary
A significant decrease in the minimum sea ice extent has been observed since the beginning of the satellite era in the late seventies. Several climate models simulate drastically different future evolution of the minimum sea ice extent. In this study, we use output diagnostics from the Community Earth System Model Large Ensemble to verify if the pathway of ocean heat transport entering the Arctic has an impact on the presence or absence of rapid sea ice declines. We find that the interaction between ocean heat transport and sea ice happens mainly over the shallow continental shelves. There, ocean heat transport can contribute to the melting of the sea ice. This melting is afterward enhance by positive feedbacks, such as the ice‐albedo feedback, and can lead to a rapid decline of the Arctic sea ice cover. In the central Arctic, the sea ice is more sensitive to atmospheric heat than to ocean heat.

50
Arctic sea ice / Re: 2018 sea ice area and extent data
« on: December 08, 2018, 02:28:42 PM »
An image to show why I think that for the next few days area gain on the Atlantic Front will be low or even -ve.

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