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gerontocrat

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Re: 2018 sea ice area and extent data
« Reply #1300 on: August 04, 2018, 09:58:10 AM »
JAXA ARCTIC EXTENT 6,204,054 km2(August 3, 2018)

Just to add to Juan's post....
- Extent loss in the last 3 days was about the average or a bit below for this time of year,
- Extent is now 79 k km2  (1.3%) below the 2010's average extent on this date,
- and just 24 k (0.4%) above 2017,
- Extent loss to date is now 420k 293 310k km2 (3.9 %) below the 2008-2017 average, with 80.3 % of the average melting season done.

Resulting minimum from average remaining melt is  4.24 million km2, (excluding 2012 from the average gives 4.32 million km2). Range of results from last ten years remaining melt is 3.47 to 4.58 million km2. For a minimum at 2nd lowest remaining melt needs to be about 9% above average, for a new record low 40%.

That 2017 feeling fades yet but still lingers on - extent losses are not still yet enough to catch up on the slow melt to date and NSIDC Area losses have slowed significantly. There is, on average, just under 20 % (40 days) of further extent loss to go. Could the melting season last a bit longer than that - Yes.  On the other hand, could extent loss sharply reduce? Yes.

As a result of these persistent higher than average extent loss, a September minimum down one bin in the range of 4.25 to 4.75 million km2, and perhaps even another bin lower, now looks increasingly possible or even likely. But that is still possibly 0.5 0.4 0.3 million km2 above 2nd place and about 0.8 million km2 above the 2012 outlier.

ps: I won't be making a vote on the minimum until the last moment. Breathlessly awaiting PIOMAS volume for July.
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Thawing Thunder

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Re: 2018 sea ice area and extent data
« Reply #1301 on: August 04, 2018, 01:36:01 PM »
I won't be making a vote on the minimum until the last moment. Breathlessly awaiting PIOMAS volume for July.
I suppose the June volume data didn't clarify much your doubts, Gero. To me at least it seems we're still sticking in a highly volatile, contradictory and uncertain season.
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gerontocrat

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Re: 2018 sea ice area and extent data
« Reply #1302 on: August 04, 2018, 02:36:25 PM »
NSIDC Total Area as at 3 August (5 day trailing average) =  4,593,103 km2
This is 208  241 251 k above the 2010-2017 average area


Quote
Posted by: Thawing Thunder
« on: Today at 01:36:01 PM » Insert Quote
Quote
Quote from: gerontocrat on Today at 09:58:10 AM
I won't be making a vote on the minimum until the last moment. Breathlessly awaiting PIOMAS volume for July.
I suppose the June volume data didn't clarify much your doubts, Gero. To me at least it seems we're still sticking in a highly volatile, contradictory and uncertain season.

Too right, confusion reigns - up, down, sideways.
Area loss 3 Aug                                        57k,
Extent loss  2 Aug (5 day average)             91k,
Extent GAIN 2 Aug (daily) 14k, loss 3 Aug 115k

Total Area loss 57 K, Central Seas loss 47 k, Periphery loss 8 k, Other Seas loss 2 k  
Analysis of individual seas.

Pacific Side
- The Bering Sea - finished,
- Chukchi Sea loss 4 k, area is now well below the 2010's average,
Atlantic Side
- Baffin Sea loss 3 k, area 49k - less than 5% of 1980's average maximum,
- Greenland Sea loss 4 k,
- Barents Sea - finished,
- The Kara Sea area loss 4 k, area is now at 46 k, 5% of 1980's average maximum.
- The Laptev Sea area loss 5 k.
CAB
- Beaufort Sea loss 21 k,
- The Central Arctic Sea LOSS 13 k,
- The Canadian Archipelago loss 0 k,
- East Siberian Sea loss 0 k .
Other seas
- St Lawrence -finished,
- Hudson Bay area loss 2 k, Area now 63 k and just about at average.
- The Okhotsk Sea - finished.

On average, this is when daily area loss declines sharply  This area loss of 57 k is 10 k below this day's 2010's average. The  5 day trailing average extent loss in contrast averaged over 100k per day for the last five  days (5 day average eliminates most of the ups and downs of daily extent measures and the monthly adjustments). But daily extent rose by 14k on the 2nd August but fell by 115k on the 3 August. Extent losses are still catching up with area losses again.

Qu1. The question is - will above average area losses follow the big NSIDC daily extent losses ? Not on July 31 or August 1 & 2 & 3, that's for sure.

Qu2. How low will Greenland Sea Ice Area go ? If export of ice down the FRAM strait is finished for this season (see Wipneus fram strait animation on PIOMAS August thread) and that warmth keeps drifting up from the Atlantic (that blocking high from Western Europe across the Atlantic is liable to stay there for some time) then....
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Juan C. García

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Re: 2018 sea ice area and extent data
« Reply #1303 on: August 05, 2018, 05:53:01 AM »
[ADS-NIPR-JAXA] ASI Extent.

August 4th, 2018: 6,156,200 km2, a drop of -47,854 km2.
2018 is the fifth lowest on record.
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.

Steven

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Re: 2018 sea ice area and extent data
« Reply #1304 on: August 05, 2018, 01:57:59 PM »
NSIDC sea ice area is currently 8th lowest for the date:


gerontocrat

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Re: 2018 sea ice area and extent data
« Reply #1305 on: August 05, 2018, 08:28:11 PM »
JAXA ARCTIC EXTENT 6,156,200 km2(August 4, 2018)

Posts will be erratic for a few days - things happening.

Just to add to Juan's post....
- Extent loss in the last 4 days was about the average or a bit below for this time of year,
- Extent is now 48 k km2  (0.8%) below the 2010's average extent on this date,
- and 114 k (1.8%) above 2017 (which had a late burst of melt before an even later series of low extent losses) ,
- Extent loss to date is now 420k 293 310 334 km2 (4.1 %) below the 2008-2017 average, with 81.0 % of the average melting season done.

Resulting minimum from average remaining melt is  4.26 million km2, (excluding 2012 from the average gives 4.34 million km2). Range of results from last ten years remaining melt is 3.55 to 4.59 million km2. For a minimum at 2nd lowest remaining melt needs to be about 10% above average, for a new record low 40%.

That 2017 feeling returns - extent losses are not catching up on the slow melt to date and NSIDC Area losses have slowed significantly. There is, on average, under 20 % (39 days) of further extent loss to go. Could the melting season last a bit longer than that - Yes.  On the other hand, could extent loss sharply reduce? Yes.

As a result of these persistent higher than average extent loss, a September minimum down one bin in the range of 4.25 to 4.75 million km2, and perhaps even another bin lower, now looks increasingly possible or even likely. But that is still possibly 0.5 0.4 0.3 million km2 above 2nd place and about 0.8 million km2 above the 2012 outlier.

ps: I won't be making a vote on the minimum until the last moment. Breathlessly awaited PIOMAS volume for July - tells me vote for the 210's average minimum, but I wait.
"Para a Causa do Povo a Luta Continua!"
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gerontocrat

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Re: 2018 sea ice area and extent data
« Reply #1306 on: August 05, 2018, 09:31:56 PM »
NSIDC Total Area as at 3 August (5 day trailing average) =  4,537,926  km2
This is 208  241 251 255 k above the 2010-2017 average area


Total Area loss 55 K, Central Seas loss 48 k, Periphery loss 7 k, Other Seas loss 0 k  
Analysis of individual seas.

Pacific Side
- The Bering Sea - finished,
- Chukchi Sea loss 2 k, area is a still a bit below the 2010's average,
Atlantic Side
- Baffin Sea loss 2 k, area 47k - less than 5% of 1980's average maximum,
- Greenland Sea loss 4 k,
- Barents Sea - finished,
- The Kara Sea area loss 2 k, area is now at 44 k, just under 5% of 1980's average maximum.
- The Laptev Sea area loss 6 k.
CAB
- Beaufort Sea GAIN 1 k,
- The Central Arctic Sea LOSS 35 k,
- The Canadian Archipelago loss 3 k,
- East Siberian Sea loss 0 k .
Other seas
- St Lawrence -finished,
- Hudson Bay area loss 0 k, Area now 63 k andand being stubborn - it's that little enclosed bay right in the north that I always forget about that is retaining ice cover,
- The Okhotsk Sea - finished.

On average, this is when daily area loss declines sharply  This area loss of 57 k is circa 5k below this day's 2010's average.

Qu1. The question is - will above average area losses return in the last 40 days or so of the season ? Not on July 31 to August 4, that's for sure.

Qu2. How low will Greenland Sea Ice Area go ? If not for the complete oddity that was 2002, the Greenland sea would have been at a record low for 158 days out of the 217 days of the year to date.
« Last Edit: August 05, 2018, 10:21:29 PM by gerontocrat »
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Tor Bejnar

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Re: 2018 sea ice area and extent data
« Reply #1307 on: August 05, 2018, 10:06:52 PM »
...
Total Area loss 555 K, ...
So, the first 5 century drop.  It's new math:  47+8 = 555
 :o ;D :-\

(Usually I send a PM for such typos, but I've got to run...)
Arctic ice is healthy for children and other living things.

gerontocrat

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Re: 2018 sea ice area and extent data
« Reply #1308 on: August 05, 2018, 10:48:31 PM »
...
Total Area loss 555 K, ...
So, the first 5 century drop.  It's new math:  47+8 = 555
 :o ;D :-\

(Usually I send a PM for such typos, but I've got to run...)
Better to do it in public, my eyesight is crap, I forget to put on my glasses, and I often don't notice my messages.

Wait till you get to my age, which is a secret only known to the Kremlin.
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Hautbois

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Re: 2018 sea ice area and extent data
« Reply #1309 on: August 05, 2018, 10:55:39 PM »
Time to break out 2018's Arctic minimum running back chart (named after the way it will wiggle through a crowd of dots in a few weeks' time).

magnamentis

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Re: 2018 sea ice area and extent data
« Reply #1310 on: August 05, 2018, 11:05:30 PM »
Better to do it in public, my eyesight is crap, I forget to put on my glasses, and I often don't notice my messages.

Wait till you get to my age, which is a secret only known to the Kremlin.

i hear you, which is why i started to have glasses in each room not having to run after them all the times LOL

eyesight is definitely where my/our age is showing relentlessly ;)
« Last Edit: August 06, 2018, 01:38:57 AM by magnamentis »

gerontocrat

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Re: 2018 sea ice area and extent data
« Reply #1311 on: August 05, 2018, 11:24:42 PM »
Time to break out 2018's Arctic minimum running back chart (named after the way it will wiggle through a crowd of dots in a few weeks' time).

i hear you, which is why i started to have glasses in each room not having to run after them all the times LOL

eyesight is definitely where my/our age is showing relentlessly ;)
magnamentis - you picked up the wrong post to quote. That's cheered me up.
"Para a Causa do Povo a Luta Continua!"
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magnamentis

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Re: 2018 sea ice area and extent data
« Reply #1312 on: August 06, 2018, 01:38:02 AM »
Better to do it in public, my eyesight is crap, I forget to put on my glasses, and I often don't notice my messages.

Wait till you get to my age, which is a secret only known to the Kremlin.

i hear you, which is why i started to have glasses in each room not having to run after them all the times LOL

eyesight is definitely where my/our age is showing relentlessly ;)
magnamentis - you picked up the wrong post to quote. That's cheered me up.

and that was with glasses LOL, gonna try to correct it, thanks for saving me ;)

having fun is healty, hence it was worth it  8)

Juan C. García

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Re: 2018 sea ice area and extent data
« Reply #1313 on: August 06, 2018, 05:49:54 AM »
[ADS-NIPR-JAXA] ASI Extent.

August 5th, 2018: 6,073,982 km2, a drop of -82,218 km2.
2018 is the fifth lowest on record.
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.

Shared Humanity

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Re: 2018 sea ice area and extent data
« Reply #1314 on: August 06, 2018, 03:09:55 PM »
Looking at that chart, we cannot entirely rule out a 2nd place finish.

Juan C. García

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Re: 2018 sea ice area and extent data
« Reply #1315 on: August 06, 2018, 11:22:26 PM »
On this table, we can see the drops that 2018 should have to match any of the lowest years by Aug 15th.

So, the questions could be like this one: Does 2018 will have a daily average drop greater than 87K km2, so it will become the third lowest on record by August 15th?

Let's wait and see.   8)
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.

Shared Humanity

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Re: 2018 sea ice area and extent data
« Reply #1316 on: August 06, 2018, 11:42:13 PM »
I think not likely. What I am interested in is whether the end of the melt season be later than normal.

Juan C. García

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Re: 2018 sea ice area and extent data
« Reply #1317 on: August 07, 2018, 05:50:05 AM »
[ADS-NIPR-JAXA] ASI Extent.

August 6th, 2018: 5,967,526 km2, a century drop of -106,456 km2.
2018 is the fifth lowest on record.
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.

oren

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Re: 2018 sea ice area and extent data
« Reply #1318 on: August 07, 2018, 05:57:43 AM »
It's certainly not giving up.

Stephan

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Re: 2018 sea ice area and extent data
« Reply #1319 on: August 07, 2018, 08:16:41 AM »
I have updated the extent anomaly graph.
July 2018 is 0,07 mio. km² above the long-term linear trend. The deviation has a little bit decreased in comparison to June 2018. I wonder whether the century drops end of July and beginning of August will further lead to a smaller deviation from the long-term linear trend in August.
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gerontocrat

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Re: 2018 sea ice area and extent data
« Reply #1320 on: August 07, 2018, 08:24:51 AM »
JAXA ARCTIC EXTENT 5,967,526 km2(August 6, 2018)

take an enforced day off... and look what happens EDIT : do the stuff at 7.30 a.m. BST while still asleep and typos abound.

Just to add to Juan's post....
- Extent loss in the last 2 days was well below above the average  for this time of year,
- Extent is now 97 k km2  (1.8 %) below the 2010's average extent on this date,
- and 58 k (1.0%) above 2017 (which had a late burst of melt at this time before an even later series of low extent losses) ,
- Extent loss to date is now 300 km2 (3.6 %) below the 2008-2017 average, with 82.2 % of the average melting season done.

Resulting minimum from average remaining melt is  4.23 million km2, (excluding 2012 from the average gives 4.29 million km2 - a reducing difference). Range of results from last ten years remaining melt is 3.65 to 4.53 million km2 - also a narrowing range. For a minimum at 2nd lowest remaining melt needs to be about 9% above average, for a new record low 33%.

That 2017 feeling diminishes- even though extent losses are not catching up on the slow melt to date and NSIDC Area losses have slowed significantly. There is, on average, well under 20 % (37 days) of further extent loss to go. Could the melting season last a bit longer than that - Yes.  On the other hand, could extent loss sharply reduce? Yes.

As a result of these persistent higher than average extent loss, a September minimum down yet another bin in the range of 4.00 to 4.50 million km2, and perhaps even another bin lower, now looks increasingly possible or even likely. But that is still possibly 0.5 0.4 0.3 0.2 million km2 above 2nd place and about 0.8 million km2 above the 2012 outlier.

ps: I won't be making a vote on the minimum until the last moment - Saturday.  5 days is a long time in this story.
« Last Edit: August 07, 2018, 11:59:30 AM by gerontocrat »
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uniquorn

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Re: 2018 sea ice area and extent data
« Reply #1321 on: August 07, 2018, 01:03:06 PM »
Quote
ps: I won't be making a vote on the minimum until the last moment - Saturday.  5 days is a long time in this story.
Gerontocrat, do you think the average of 2016 and 2017(together) would be helpful to make a decision?

gerontocrat

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Re: 2018 sea ice area and extent data
« Reply #1322 on: August 07, 2018, 03:09:58 PM »
Quote
ps: I won't be making a vote on the minimum until the last moment - Saturday.  5 days is a long time in this story.
Gerontocrat, do you think the average of 2016 and 2017(together) would be helpful to make a decision?
Nope. I am thinking of a trip to Wales to consult the Druids and their Runes, or to Rome for a look at some entrails of chicken at the Temple of the Vestal Virgins, or maybe to Mystic Meg and her Tarot cards.

A bit more seriously, at this point in time so close to the end of the season, the melting season thread (at least those posts refraining from hyperbole), regarding outlooks on the weather, SST's, the condition of the ice and so on, may be the only guide as to whether or not to adjust a simple average of the last 10 years down (or up).
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gerontocrat

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Re: 2018 sea ice area and extent data
« Reply #1323 on: August 07, 2018, 03:34:41 PM »
NSIDC Total Area as at 6 August (5 day trailing average) =  4,409,94  km2
This is down 12k in the last 2 days (from 255) to 243 k above the 2010-2017 average area

 
Total Area loss 69 K - 5 Aug, 59 K - 6 Aug,

Central Seas loss 63 K - 5 Aug, 51 K - 6 Aug,
Periphery loss  loss 5 K - 5 Aug  4 K - 6 Aug,
Other Seas loss  loss 1 K - 5 Aug, 4 K - 6 Aug.

Analysis of individual seas.
Pacific Side
- The Bering Sea - finished,
- Chukchi Sea loss 4 k, area is a still a bit below the 2010's average,
Atlantic Side
- Baffin Sea loss 3 k, area 41k - well less than 5% of 1980's average maximum,
- Greenland Sea loss 0 k, loss slowing right down,
- Barents Sea - finished,
- The Kara Sea area loss 3 k, area is now at 38 k, well under 5% of 1980's average maximum.
- The Laptev Sea area loss 9 k - impressive.
CAB
- Beaufort Sea loss 7 k,
- The Central Arctic Sea LOSS 23 k,
- The Canadian Archipelago loss 7 k,
- East Siberian Sea gain 1 k .
Other seas
- St Lawrence -finished,
- Hudson Bay area loss 4 k, Area now 57 k, being stubborn but now less than 5% of 1980's average maximum- it's that little enclosed bay right in the north that I always forget about that is retaining ice cover,
- The Okhotsk Sea - finished.

On average, this is when daily area loss declines sharply  The area losses of 69 and 59 k of the last 2 days is below this day's 2010's average.

Qu1. The question is - will above average area losses return in the last 35 days or so of the season ?

Qu2. How low will Greenland Sea Ice Area go ? If not for the complete oddity that was 2002, the Greenland sea would have been at a record low for 158 days out of the 217 days of the year to date. But in the last 2 days losses almost stopped.
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Juan C. García

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Re: 2018 sea ice area and extent data
« Reply #1324 on: August 07, 2018, 04:31:07 PM »
NSIDC Total Area as at 3 August (5 day trailing average) =  4,537,926  km2

NSIDC Total Area as at 6 August (5 day trailing average) =  4,409,94  km2
This is down 12k in the last 2 days (from 255) to 243 k above the 2010-2017 average area



Hi gerontocrat.
4,537,926 km2 - 4,409,940 km2 = 127,986 km2 = 127.9K km2.
Not 12k...

Am I correct?
Thanks for all your work. Just a drop of 12k seems too little to be real.

PS: There are 3 days between the quotes and I don´t follow the NSIDC área (only in your posts), so I could be wrong...
« Last Edit: August 07, 2018, 04:46:04 PM 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.

Downpuppy

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Re: 2018 sea ice area and extent data
« Reply #1325 on: August 07, 2018, 04:46:09 PM »
Juan;
The 2018 drop is 128k, while the average was 116k. Hence, 12k closer to average.

Juan C. García

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Re: 2018 sea ice area and extent data
« Reply #1326 on: August 07, 2018, 06:15:12 PM »
Juan;
The 2018 drop is 128k, while the average was 116k. Hence, 12k closer to average.


Thanks!  :)
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.

Neven

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Re: 2018 sea ice area and extent data
« Reply #1327 on: August 07, 2018, 11:45:58 PM »
Compactness almost highest in the 2005-2018 period, but I don't expect it to follow 2014:
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gerontocrat

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Re: 2018 sea ice area and extent data
« Reply #1328 on: August 08, 2018, 12:28:13 AM »
NSIDC Total Area as at 3 August (5 day trailing average) =  4,537,926  km2

NSIDC Total Area as at 6 August (5 day trailing average) =  4,409,94  km2
This is down 12k in the last 2 days (from 255) to 243 k above the 2010-2017 average area


Sorry - Bad wording - 2 days loss slightly above average meant that the 2018 total area that was 255 k above 2017 total area went down by 12k to 243 k above total 2017 area, i.e. not referring to actual area loss. Will revise the wording tomorrow.


Hi gerontocrat.
4,537,926 km2 - 4,409,940 km2 = 127,986 km2 = 127.9K km2.
Not 12k...

Am I correct?
Thanks for all your work. Just a drop of 12k seems too little to be real.

PS: There are 3 days between the quotes and I don´t follow the NSIDC área (only in your posts), so I could be wrong...
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Juan C. García

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Re: 2018 sea ice area and extent data
« Reply #1329 on: August 08, 2018, 05:29:49 AM »
Compactness almost highest in the 2005-2018 period, but I don't expect it to follow 2014:


I can't understand how the compactness is that high and at the same time, I see on Bremen a huge area that could melt in the near future. And I am specially concern if a cyclone develops on the Arctic. It does not have to be as the GAC 2012, just strong enough and in the right place: the ESS and Laptev.
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: 2018 sea ice area and extent data
« Reply #1330 on: August 08, 2018, 05:48:29 AM »
[ADS-NIPR-JAXA] ASI Extent.

August 7th, 2018: 5,885,720 km2, a drop of -81,806 km2.
2018 is the fifth lowest on record.
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.

Wherestheice

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Re: 2018 sea ice area and extent data
« Reply #1331 on: August 08, 2018, 07:04:45 AM »
Compactness almost highest in the 2005-2018 period, but I don't expect it to follow 2014:


I can't understand how the compactness is that high and at the same time, I see on Bremen a huge area that could melt in the near future. And I am specially concern if a cyclone develops on the Arctic. It does not have to be as the GAC 2012, just strong enough and in the right place: the ESS and Laptev.

Perhaps the compactness is so great in the CAB, it "steals the show".
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Re: 2018 sea ice area and extent data
« Reply #1332 on: August 08, 2018, 08:03:16 AM »
The compactness mystery has something to do with the differences between NSIDC and AMSR2 due to differences in sensors and algorithms. AMSR2 compactness is more middle-of-the-road, while NSIDC and is rather high. Wipneus as usual comes to the rescue. Click images for better resolution. Bookmark the links.

https://sites.google.com/site/arctischepinguin/home/amsr2/grf/amsr2-compact-compare.png?attredirects=0

https://sites.google.com/site/arctischepinguin/home/amsr2/grf/amsr2-area-all-cmpare.png?attredirects=0

https://sites.google.com/site/arctischepinguin/home/amsr2/grf/amsr2-extent-all-cmpare.png
« Last Edit: August 08, 2018, 08:09:26 AM by oren »

gerontocrat

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Re: 2018 sea ice area and extent data
« Reply #1333 on: August 08, 2018, 09:17:48 AM »
JAXA ARCTIC EXTENT 5,967,526 km2(August 6, 2018)

Just to add to Juan's post....
- Extent loss in the last 3 days was above the average  for this time of year,
- Extent is now 102 k km2  (1.7 %) below the 2010's average extent on this date,
- and 81 k (1.1%) above 2017 (which had a late burst of melt at this time before an even later series of low extent losses) ,
- Extent loss to date is now 291 km2 (3.5 %) below the 2008-2017 average, with 83.3 % of the average melting season done.

Resulting minimum from average remaining melt is  4.22 million km2, (excluding 2012 from the average gives 4.28 million km2 - a reducing difference). Range of results from last ten years remaining melt is 3.69 to 4.55 million km2 - also a narrowing range. For a minimum at 2nd lowest remaining melt needs to be about 9% above average,for a new record low 33%. Note: ERROR in calculation used in previous posts.

For a new record low remaining melt would need to be 2.71 million km2 as opposed to the average remaining melt of 1.67 million km2, i.e 1.04 million (62.5%) above the average. Not feasible.

That 2017 feeling diminishes- even though extent losses are only slowly catching up on the slow melt to date and NSIDC Area losses have slowed significantly. There is, on average, just 16.7% (36 days) of further extent loss to go. Could the melting season last a bit longer than that - Yes.  On the other hand, could extent loss sharply reduce? Yes.

As a result of these persistent higher than average extent loss, a September minimum down yet another bin in the range of 4.00 to 4.50 million km2, and perhaps even another bin lower, now looks increasingly likely. But that is still possibly 0.5 0.4 0.3 0.2 million km2 above 2nd place and about 0.8 million km2 above the 2012 outlier.

ps: I won't be making a vote on the minimum until the last moment - Saturday.  5 days is a long time in this story.
[/quote]
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gerontocrat

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Re: 2018 sea ice area and extent data
« Reply #1334 on: August 08, 2018, 02:39:47 PM »
NSIDC Total Area as at 6 August (5 day trailing average) =  4,363,048  km2
This is now 250 k above the 2010-2017 average total area


Total Area loss 47K ,

Central Seas loss 37k
Periphery loss  loss 4k,
Other Seas loss  loss 5k.

Analysis of individual seas.
Pacific Side
- The Bering Sea - finished,
- Chukchi Sea loss 5 k, area is a still a bit below the 2010's average,
Atlantic Side
- Baffin Sea loss 4 k, area 37 k - well less than 5% of 1980's average maximum,
- Greenland Sea gain 1 k, loss stalled,
- Barents Sea - finished,
- The Kara Sea area loss 5 k, area is now at 32 k, well under 5% of 1980's average maximum.
- The Laptev Sea area loss 12 k - very impressive.
CAB
- Beaufort Sea loss 6 k,
- The Central Arctic Sea gain 3 k,
- The Canadian Archipelago loss 9 k,
- East Siberian Sea loss 3 k .
Other seas
- St Lawrence -finished,
- Hudson Bay area loss 5 k, Area now 52 k, less than 5% of 1980's average maximum- almost done,
- The Okhotsk Sea - finished.

On average, this is when daily area loss declines sharply  The area loss of 47 k  is below this day's 2010's average by 5k. In contrast extent loss was nearly 90k.

Qu1. The question is - will above average area losses return in the last 35 days or so of the season ?

Qu2. How low will Greenland Sea Ice Area go ? If not for the complete oddity that was 2002, the Greenland sea would have been at a record low for 158 days out of the 217 days of the year to date. But in the last 3 days losses have stopped.

Kara Area graph attached. Today was the first day that Kara Sea area is lowest for the day in the satellite record. If another 15k of area loss occurs then that would be an all-time record low - 30+ days to do it in.
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gerontocrat

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Re: 2018 sea ice area and extent data
« Reply #1335 on: August 08, 2018, 10:04:29 PM »
A last thought for the day.

Perhaps by starting as the base the 1980's average maximum sea ice area for each sea, it could be considered that when sea ice area for a sea is less than 15% of that maximum, the sea has so little ice as to become basically irrelevant as far as the remainder of the melt season is concerned..

Using that measure, as of 7 August all the Arctic Seas have no significance for the rest of the melt season except for the Beaufort, The Eastern Siberian, The Canadian Archipelago and the Central Arctic.

Why 15% ? Why not, given that by then the sea is 85% open ocean.

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Juan C. García

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Re: 2018 sea ice area and extent data
« Reply #1336 on: August 09, 2018, 05:47:58 AM »
[ADS-NIPR-JAXA] ASI Extent.

August 8th, 2018: 5,824,414 km2, a drop of -61,306 km2.
2018 is the fifth lowest on record.
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: 2018 sea ice area and extent data
« Reply #1337 on: August 09, 2018, 09:24:39 AM »
JAXA ARCTIC EXTENT 5,824,414 km2(August 8, 2018)

Just to add to Juan's post....
- Extent loss below the average  for this time of year by about 10k,
- Extent is now 71 k km2  (1.2 %) below the 2010's average extent on this date,
- and 156 k (1.7%) above 2017 (which had a late burst of melt at this time before an even later series of low extent losses) ,
- Extent loss to date is now 310 km2 (3.7 %) below the 2008-2017 average, with 84 % of the average melting season done.

Resulting minimum from average remaining melt is  4.24 million km2, (excluding 2012 from the average gives 4.29 million km2 - a reducing difference). Range of results from last ten years remaining melt is 3.81 to 4.63 million km2 - also a narrowing range. For a minimum at 2nd lowest remaining melt needs to be about 11% above average. For a new record low remaining melt would need to be 2.65 million km2 as opposed to the average remaining melt of 1.59 million km2, i.e 1.06 million (67 %) above the average. Not feasible.

That 2017 feeling diminishes- even though extent losses are only slowly catching up on the slow melt to date and NSIDC Area losses have slowed significantly. There is, on average, just 16% (35 days) of further extent loss to go. Could the melting season last a bit longer than that - Yes.  On the other hand, could extent loss sharply reduce? Yes.

As a result of these persistent higher than average extent loss, a September minimum down yet another bin in the range of 4.00 to 4.50 million km2, and perhaps even another bin lower, now looks increasingly likely. But that is still possibly 0.5 0.4 0.3 0.2 million km2 above 2nd place and about 0.8 million km2 above the 2012 outlier.

ps: I won't be making a vote on the minimum until the last moment - Saturday.  3 days is a long time in this story.
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gerontocrat

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Re: 2018 sea ice area and extent data
« Reply #1338 on: August 09, 2018, 02:11:02 PM »
NSIDC Total Area as at 8 August (5 day trailing average) =  4,317,755  km2
This is now 258 k above the 2010-2017 average total area


Total Area loss 45K ,

Central Seas loss 42k
Periphery loss  loss 3k,
Other Seas loss  loss 1k.

Analysis of individual seas.
Pacific Side
- The Bering Sea - finished,
- Chukchi Sea loss 3 k, area is a still a bit below the 2010's average,
Atlantic Side
- Baffin Sea loss 3 k, area 37 k - well less than 5% of 1980's average maximum,
- Greenland Sea  0 k, loss stalled,
- Barents Sea - finished,
- The Kara Sea area loss 4 k, area is now at 29 k, well under 5% of 1980's average maximum.
- The Laptev Sea area loss 10 k -  area 115k less than 15% of '80s maximum,impressive.
CAB
- Beaufort Sea loss 4 k,
- The Canadian Archipelago loss 11 k,
- East Siberian Sea loss 6 k .
- The Central Arctic Sea loss 4 k,

Other seas

- St Lawrence -finished,
- Hudson Bay area loss15 k, Area now 51 k, less than 5% of 1980's average maximum- almost done,
- The Okhotsk Sea - finished.

On average, this is when daily area loss declines sharply  The area loss of 45 k  is below this day's 2010's average by 8 k. In contrast extent loss was 80+k.

Qu1. The question is - will above average area losses return in the last 35 days or so of the season ? Not for several days so far.

Qu2. How low will Greenland Sea Ice Area go ? If not for the complete oddity that was 2002, the Greenland sea would have been at a record low for 158 days out of the 217 days of the year to date. But in the last 4 days losses have stopped.

Kara Area graph attached. Today was the 2nd day that Kara Sea area is lowest for the day in the satellite record. If another 12 k of area loss occurs then that would be an all-time record low - 30+ days to do it in.
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Juan C. García

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Re: 2018 sea ice area and extent data
« Reply #1339 on: August 10, 2018, 06:17:28 AM »
[ADS-NIPR-JAXA] has not updated the information.
Please someone else post the updated data, when you see it.

Thanks!

https://ads.nipr.ac.jp/vishop/#/extent
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.

etienne

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Re: 2018 sea ice area and extent data
« Reply #1340 on: August 10, 2018, 06:47:01 AM »
Today's Jaxa's value is 5'744'590, a drop of 79'824. Still in the fifth position.
---------------------------------
On the graph, for older values, when there was no data available, I used next day data.
« Last Edit: August 10, 2018, 07:23:45 AM by etienne »

gerontocrat

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Re: 2018 sea ice area and extent data
« Reply #1341 on: August 10, 2018, 10:02:41 AM »
JAXA ARCTIC EXTENT 5,744,590 km2(August 9, 2018)

Just to add to Juan's post that didn't happen and was filled by that rather good graph by etienne....
- Extent loss of 80 k above the average for this time of year by a bit less than 10k,
- Extent is now 71 k km2  (1.2 %) below the 2010's average extent on this date,
- and 155 k (2.7%) above 2017 (which had a late burst of melt up to this time before a later series of low extent losses) ,
- Extent loss to date is now 304 km2 (3.6 %) below the 2008-2017 average, with 85 % of the average melting season done.

Resulting minimum from average remaining melt is  4.23 million km2, (excluding 2012 from the average gives 4.27 million km2 - a reducing and not very significant difference). Range of results from last ten years remaining melt is 3.89 to 4.63 million km2 - also a narrowing range. For a minimum at 2nd lowest remaining melt needs to be about 11% above average. For a new record low remaining melt would need to be 2.57 million km2 as opposed to the average remaining melt of 1.51 million km2, i.e 1.06 million (70 %) above the average. Not feasible.

Of interest (?) is that in 2012 melt from this point was just 0.4 million (23%) above the average.
That 2017 feeling diminishes- even though extent losses are only slowly catching up on the slow melt to date and NSIDC Area losses have slowed significantly. There is, on average, just 15% (34 days) of further extent loss to go. Could the melting season last a bit longer than that - Yes.  On the other hand, could extent loss sharply reduce? Yes.

As a result of these persistent higher than average extent loss, a September minimum in the range of 4.00 to 4.50 million km2 seems probable, and perhaps even another bin lower (3.75 to 4.25) looks possible. But that is still possibly 0.2 million km2 above 2nd place and about 0.8 million km2 above the 2012 outlier.

ps: I still won't be making a vote on the minimum until the last moment on Saturday.  3 days is a long time in this story. I think a browse through the melting season thread and a good look a the weather outlook might be a good idea. Any clue as to the chances of a late burst or a late slowdown in melt to modify the result using average remaining melt would be welcome.
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gerontocrat

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Re: 2018 sea ice area and extent data
« Reply #1342 on: August 10, 2018, 02:54:59 PM »
NSIDC Total Area as at 9 August (5 day trailing average) =   4,265,743 km2
This is now 263 k above the 2010-2017 average total area for this date

 
Total Area loss 52 K ,

Central Seas loss         49 k
Peripheral Seas loss ZERO k, signal re approaching end of melting season?
Other Seas loss             3 k.

Analysis of individual seas.
Pacific Side
- The Bering Sea - finished,
- Chukchi Sea loss 2 k, area is a still a bit below the 2010's average,
Atlantic Side
- Baffin Sea loss 2 k, area 35 k - well under 5% of 1980's average maximum,
- Greenland Sea  gain 1k, loss stalled or in reverse,
- Barents Sea - finished,
- The Kara Sea area loss 1 k, area is now at 28 k, well under 5% of 1980's average maximum.
- The Laptev Sea area loss 9 k -  area 106k, less than 15% of maximum.
CAB
- Beaufort Sea loss 7 k,
- The Canadian Archipelago loss 8 k,
- East Siberian Sea loss 4 k .
- The Central Arctic Sea loss 19 k,

Other seas

- St Lawrence -finished,
- Hudson Bay area loss 3 k, Area now 48 k, less than 5% of 1980's average maximum- almost done,
- The Okhotsk Sea - finished.

On average, this is when daily area loss declines sharply  The area loss of 51 k  is below this day's 2010's average by 5 k. In contrast extent loss (also 5-day trailing average)) was 75k.

Qu1. Will above average area losses return in the last 33 days or so of the season ? Not for several days so far.

Qu2. How low will Greenland Sea Ice Area go ? If not for the complete oddity that was 2002, the Greenland sea would have been at a record low for 158 days out of the 217 days of the year to date. But in the last 5 days losses have stopped and even seem small gains.
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gerontocrat

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Re: 2018 sea ice area and extent data
« Reply #1343 on: August 10, 2018, 03:11:06 PM »
At this late stage in the season, one's attention is drawn even more to the big beast of the Arctic Ocean- the 3.25 million km2 of the Central Arctic Sea.

One expects area loss to occur earlier than extent loss (the 15% rule and 625 km2 NSIDC grid resolution), but I did not expect to sea area loss far below the 2010's average while extent loss was so far above the 201's average.

Compaction? But the conventional wisdom has it that surface (2m) air temperatures in the arctic are rapidly cooled over ice covered sea, hence air temperatures North of 80 barely rise above 1 or 2 degrees celsius even in the brief Arctic summer. The more compact the ice (i.e. less open water), the greater the cooling effect. BUT in the last few days temperatures North of 80 have risen one or two degrees above normal (an unusual event in summer).
« Last Edit: August 10, 2018, 08:06:49 PM by gerontocrat »
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Re: 2018 sea ice area and extent data
« Reply #1344 on: August 10, 2018, 08:32:45 PM »
Maybe it is an issue of where the Central Arctic Seas boundaries are? It was cold enough until recently not to lose much area but it is more mobile so at a certain edge which is already broken up it is losing a lot of extent first?

(I am quite bad with the boundaries myself so i play the waiting game...see if it emerges in the bigger picture).
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Re: 2018 sea ice area and extent data
« Reply #1345 on: August 10, 2018, 09:56:44 PM »
I updated my 1 year trailing average extent graph using these nsidc data ftp://sidads.colorado.edu/DATASETS/NOAA/G02135/north/daily/data/
It was first posted in the wrong thread, it will be better here.

It is a little bit out of topic at this time of the year, but I find interesting that even if we don't break absolute records right now, on yearly average we are quite low, the record being for the time frame 2016 03 29 to 2017 03 28 at 10.11361.

Values are in 10^6 sq km.

Maybe it doesn't look like that, but the graph goes all the way to the 8th of August 2018.

gerontocrat

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Re: 2018 sea ice area and extent data
« Reply #1346 on: August 10, 2018, 10:24:31 PM »
Maybe it is an issue of where the Central Arctic Seas boundaries are? It was cold enough until recently not to lose much area but it is more mobile so at a certain edge which is already broken up it is losing a lot of extent first?

(I am quite bad with the boundaries myself so i play the waiting game...see if it emerges in the bigger picture).
Boundaries used by NSIDC attached - #11 is the Central Arctic
Also NSIDC Extent map as at 9 August
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Juan C. García

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Re: 2018 sea ice area and extent data
« Reply #1347 on: August 11, 2018, 05:49:08 AM »
Today's Jaxa's value is 5'744'590, a drop of 79'824. Still in the fifth position.

Thank you etienne!  :)

[ADS-NIPR-JAXA] ASI Extent.

August 10th, 2018: 5,666,808 km2, a drop of -77,782 km2.
2018 is the fifth lowest on record.
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: 2018 sea ice area and extent data
« Reply #1348 on: August 11, 2018, 10:30:59 AM »
JAXA ARCTIC EXTENT 5,666,808 km2(August 10, 2018)

Just to add to Juan's post
- Extent loss of 78 k is above the average for this date by about 5k,
- Extent is now 73 k km2  (1.3 %) below the 2010's average extent on this date,
- and 131 k (2.3%) above 2017 (which started a series of below average extent losses at this time) ,
- Extent loss to date is now 300 km2 (3.5 %) below the 2008-2017 average, with 85.6 % of the average melting season done.

Resulting minimum from average remaining melt is  4.23 million km2, (excluding 2012 from the average gives 4.26 million km2 - a reducing and insignificant difference). Range of results from last ten years remaining melt is 3.90 to 4.60 million km2 - also a narrowing range. For a minimum at 2nd lowest remaining melt needs to be about 11% above average. For a new record low remaining melt would need to be 2.49 million km2 as opposed to the average remaining melt of 1.44 million km2, i.e 1.05 million (73 %) above the average. Not feasible.

Of interest (?) is that in 2012 melt from this point was just 0.33 million (23%) above the average.
That 2017 feeling diminishes- even though extent losses are only slowly catching up on the slow melt to date and NSIDC Area losses have slowed significantly. There is, on average, just 14.4% (33 days) of further extent loss to go. Could the melting season last a bit longer than that - Yes.  On the other hand, could extent loss sharply reduce? Yes.

As a result of these persistent higher than average extent loss, a September minimum in the range of 4.00 to 4.50 million km2 seems probable, and perhaps even another bin lower (3.75 to 4.25) looks possible. But that is still possibly 0.2 million km2 above 2nd place and about 0.8 million km2 above the 2012 outlier.

ps: Sept minimum vote. A browse through the melting season thread suggests a warmer few days to come than last year. On the other hand compaction in the Central Arctic is high which might slow melting. My vote must be cast, oh dear.
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Re: 2018 sea ice area and extent data
« Reply #1349 on: August 11, 2018, 10:58:55 AM »
Compactness almost highest in the 2005-2018 period, but I don't expect it to follow 2014:

And it didn't follow 2014, but still relatively high:
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