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Author Topic: Global sea ice area and extent data  (Read 86211 times)

gerontocrat

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Re: Global sea ice area and extent data
« Reply #450 on: April 04, 2019, 08:29:07 AM »
JAXA Global Sea Ice Extent as at 3 April 2019 :-  17,577,832 km2

Global Sea Ice Extent on this day is 2nd lowest, above 2017.Average Antarctic gain + average Arctic loss on this day.

- extent gain on this day 58k,  5k less than the the average gain of 63 k on this day,
- extent gain from minimum to date is 1,330k, 1,540k (54%) less than the average gain of 2,870k,
-on average 31.8% of extent gain done and 215 days to maximum ( 4-Nov),

The Perils of Projections
- last 10 years average remaining extent gain would give a maximum of 23.73 million km2,  95k more than the record low max of 2016 and 2nd lowest in the satellite record. Tomorrow 2017 extent gain were very high, so there is a good chance that then 2019 will be lowest in the satellite record, even if only for one day.
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oren

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Re: Global sea ice area and extent data
« Reply #451 on: April 04, 2019, 02:23:29 PM »
In 6 weeks it went from 0.4M to 2M km2 below the 2010s average. System volatility is certainly increasing.

Stephan

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Re: Global sea ice area and extent data
« Reply #452 on: April 05, 2019, 07:56:22 AM »
A smaller increase (as Average) in Antarctic and a larger decrease (as average) in the Arctic today led to a new record low in global sea ice, as "announced" by several people here in this forum. Today it came true.

gerontocrat

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Re: Global sea ice area and extent data
« Reply #453 on: April 05, 2019, 12:58:33 PM »
JAXA Global Sea Ice Extent as at 3 April 2019 :-   17,592,526 km2

Continuing Antarctic extent gain at or a bit below average and Arctic extent loss continuing at above average,  has resulted in Global Sea Ice Extent on this day being lowest. Another line being written on a previously unused part of the graph paper.

- extent gain on this day 15k,  42k less than the the average gain of 57 k on this day,
- extent gain from minimum to date is 1,340k, 1,580k (54%) less than the average gain of 2,930k,
-on average 32.4% of extent gain done and 214 days to maximum ( 4-Nov),

The Perils of Projections
- last 10 years average remaining extent gain would give a maximum of 23.69 million km2,  53k more than the record low max of 2016 and 2nd lowest in the satellite record.
____________________________________________________________________________
From now on only occasional updates unless unusual stuff going on. But maybe unusual is the new normal.
"Para a Causa do Povo a Luta Continua!"
"And that's all I'm going to say about that". Forrest Gump
"Damn, I wanted to see what happened next" (Epitaph)

gerontocrat

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Re: Global sea ice area and extent data
« Reply #454 on: April 06, 2019, 08:55:43 AM »
JAXA Global Sea Ice Extent as at 5 April 2019 :- 17,670,997 km2

Until this day, continuing Antarctic extent gain at or a bit below average and Arctic extent loss continuing at above average,  has resulted in Global Sea Ice Extent on this day being lowest. Another line being written on a previously unused part of the graph paper.

- extent gain on this day 78k,  22k more than the the average gain of 56 k on this day,
- extent gain from minimum to date is 1,420k, 1,560k (52%) less than the average gain of 2,980k,
-on average 33.1% of extent gain done and 213 days to maximum ( 4-Nov),

The Perils of Projections
- last 10 years average remaining extent gain would give a maximum of 23.71 million km2,  75k more than the record low max of 2016 and 2nd lowest in the satellite record.
____________________________________________________________________________
From now on only occasional updates unless unusual stuff going on. But maybe unusual is the new normal.
"Para a Causa do Povo a Luta Continua!"
"And that's all I'm going to say about that". Forrest Gump
"Damn, I wanted to see what happened next" (Epitaph)

Stephan

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Re: Global sea ice area and extent data
« Reply #455 on: April 07, 2019, 08:52:21 AM »
I compared the actual JAXA extent value (April 6) of Arctic and Antarctic with the decadal averages of the 10s, 00s, 90s, and 80s and calculated the cumulative difference of 2019 (example: in the Arctic we are 20 days ahead compared to the 10s, in the Antarctic we are 11 days behind the 10s average, which sums up to 31 days, almost a month).
Compared to earlier decades this difference is even bigger:
April 6, 2019 vs. 00s: 42 days
April 6, 2019 vs. 90s: 50 days
April 6, 2019 vs. 80s: 59 days (almost two months)
So there is a big difference as there is less ice to melt in the Arctic this coming melting season (so less energy needed) and more ice to form in the Antarctic this coming freezing season (more freezing energy to be released). In addition you must also take the Albedo effect into account.

b_lumenkraft

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Re: Global sea ice area and extent data
« Reply #456 on: April 07, 2019, 10:15:40 AM »
I compared

You are having a way to look at the data in such a unique way, i'm always impressed. Compare on sir!

magnamentis

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Re: Global sea ice area and extent data
« Reply #457 on: April 07, 2019, 01:33:33 PM »
I compared the actual JAXA extent value (April 6) of Arctic and Antarctic with the decadal averages of the 10s, 00s, 90s, and 80s and calculated the cumulative difference of 2019 (example: in the Arctic we are 20 days ahead compared to the 10s, in the Antarctic we are 11 days behind the 10s average, which sums up to 31 days, almost a month).
Compared to earlier decades this difference is even bigger:
April 6, 2019 vs. 00s: 42 days
April 6, 2019 vs. 90s: 50 days
April 6, 2019 vs. 80s: 59 days (almost two months)
So there is a big difference as there is less ice to melt in the Arctic this coming melting season (so less energy needed) and more ice to form in the Antarctic this coming freezing season (more freezing energy to be released). In addition you must also take the Albedo effect into account.

a cumulation of time to express energy is interesting, nevertheless and even though i got your point and agree, those days are kind of overlapping (timewise) and hence should not be cumulated and used to express energy needed to melt or freeze.

if at all one could perhaps take an average between SH and NH to express an average of such kind but again, cumulation of those days are a bit abstract and can lead to misinterpretation.

to avoid such misunderstanding i repeat, i understand what you are trying to convey and i agree to your thoughts and often think about that the exact same way.

of course and as always, in case i'm to one who missed a point here, don't hesitate to enlighten me and/or elaborate further, the above just came to my mind while reading.

for the rest what others have said, generally interesting to read your various contributions  :)

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gerontocrat

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Re: Global sea ice area and extent data
« Reply #458 on: April 08, 2019, 12:13:12 PM »
JAXA Global Sea Ice Extent as at 7 April 2019 :- 17,820,478 km2

For two brief days (4-5 April) extent was lowest. But then high Antarctic gain outweighed above average Arctic loss, so extent is now 22k above 2017.

- extent gain on this day 90k,  13k more than the the average gain of 78 k on this day,
- extent gain from minimum to date is 1,420k, 1,560k (52%) less than the average gain of 2,980k,
-on average 34.7% of extent gain done and 211 days to maximum ( 4-Nov),

The Perils of Projections
- last 10 years average remaining extent gain would give a maximum of 23.71 million km2,  75k more than the record low max of 2016 and 2nd lowest in the satellite record.
____________________________________________________________________________
From now on only occasional updates unless unusual stuff going on. But maybe unusual is the new normal.
[/quote]
"Para a Causa do Povo a Luta Continua!"
"And that's all I'm going to say about that". Forrest Gump
"Damn, I wanted to see what happened next" (Epitaph)

gerontocrat

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Re: Global sea ice area and extent data
« Reply #459 on: April 13, 2019, 10:21:26 AM »
JAXA Global Sea Ice Extent as at 12 April 2019 :-  18,259,037 km2

In recent days extent gain has been at or a bit above average, so extent is now 125k above 2017.

- extent gain on this day 94k, 17k more than the the average gain of 77 k on this day,
- extent gain from minimum to date is 2.01 million km2, 1.53 million km2 (43%) less than the average gain of 2.54 milllion km2,
-on average 39.2% of extent gain done and 206 days to maximum ( 4-Nov),

The Perils of Projections
- last 10 years average remaining extent gain would give a maximum of 23.74 million km2,  108k more than the record low max of 2016 and 2nd lowest in the satellite record.
____________________________________________________________________________
From now on only occasional updates unless unusual stuff going on. But maybe unusual is the new normal.
"Para a Causa do Povo a Luta Continua!"
"And that's all I'm going to say about that". Forrest Gump
"Damn, I wanted to see what happened next" (Epitaph)

Killian

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Re: Global sea ice area and extent data
« Reply #460 on: April 14, 2019, 12:13:03 PM »
Re: Historic ASI Extent, Daily Records
(Don't know if this is the best place to post this, so if not, please move.)

I was looking at recent years' new records being in mind of my Aug 2015 prediction of new record ASI lows or near record lows for 2016-17 period (two years follwing an El Nino.) 2016 was the second lowest, as we all know. However, it also had extensive new records in the spring and fall months. since 2015, I've always wondered if these numbers of total record days might have some sort of important or useful data embedded, but have never checked.

Today I was poking around and got curious how often new daily records are set year-on-year. Using JAXA's interactive chart I got a rather startling surprise. Using 1979 as the baseline, every single year has had a least a few daily record lows. Every. Year.

That, to me, is unexpected. I just never thought about it, but see it as making the overall trend more robust than it seems just from the yearly low trend.

How many years set new yearly lows using '79 as the baseline (though it seems likely to have been lower than '78)?

'84 (5 yrs)
'85 (1 yr)
'90 (5 yrs)
'95 (5 yrs)
'99 (4 yrs)
'02 (3 yrs)
'05 (3 yrs)
'07 (2 yrs)
'12 (5 yrs)

Currently six years since the last new low. Interestingly, the shorter periods of new lows was indicative of stability, with relatively small changes giving us new lows with the downward trend. then '07 and '12 changed things a lot, with '12 clearly being really anomalous. Of course, both those last years had the dipole set up blowing ice out Fram Strait.

Short version: We consistently had new ASI summer lows since we started tracking this.