Author Topic: Global sea ice area and extent data (Read 516479 times)

gerontocrat · « **Reply #650 on:** September 12, 2019, 09:13:38 AM »

JAXA Global Sea Ice Extent as at 11 September 2019 : 22,260,424 km2

The false minimum of late August / Early September is past. So this analysis reverts to looking at the late Oct / early Nov maximum

In the last week extent has dropped, after a period of 2 weeks when overall mostly very low Arctic extent losses and somewhat above Antarctic extent gains has meant that Global Sea Ice Extent did not reduce to the false minimum but increased. Now, when extent increase is the norm, extent is reducing. Confused?

- Global extent in 3rd place,
- extent 70 k above 2016, & 120 k above 2018.
- extent gain from the March minimum to date is 6.01 million km2, 0.37 million km2 (5.7%) less than the average gain of 6.38 million km2 by this day,
-on average 70.7% of extent gain done and 54 days to the maximum in early November.

The Perils of Projections

Average remaining extent gain in the last 10 years would result in a maximum of 24.91 million km2, 2nd lowest but still 1.27 million above the extraordinary 2016 year (of which the last 3 months Oct-Dec were the most extraordinary).
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This is an odd and immensely irritating time of year - why can't the ice be good and stay nice and close to the average daily changes?

gerontocrat · « **Reply #651 on:** September 15, 2019, 11:33:43 AM »

JAXA Global Sea Ice Extent as at 14 September 2019 : 22,219,733 km2

In the last week extent has dropped, even as "the norm" returns to extent increases to the November max.

- Global extent in 3rd place,
- extent 188 k above 2016, & 108 k above 2018.
- extent gain from the March minimum to date is 5.97 million km2, 0.42 million km2 (6.6%) less than the average gain of 6.39 million km2 by this day,
-on average 70.9% of extent gain done and 51 days to the average date of maximum in early November.

The Perils of Projections

Average remaining extent gain in the last 10 years would result in a maximum of 24.85 million km2, 2nd lowest but still 1.21 million above the extraordinary 2016 year (of which the last 3 months Oct-Dec were the most extraordinary).
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gerontocrat · « **Reply #652 on:** September 19, 2019, 04:43:04 PM »

JAXA Global Sea Ice Extent as at 18 September 2019 : 22,191,387 km2

In the last week extent has dropped, even as "the norm" returns to extent increases to the November max.

- On this day Global extent became lowest again, making 119 days in 2019 at lowest,
- extent 42 k below 2016, & 164 k below 2018.
- extent gain from the March minimum to date is 5.94 million km2, 0.54 million km2 (8.4%) less than the average gain of 6.48 million km2 by this day,
-on average 71.9% of extent gain done and 47 days to the average date of maximum in early November.

The Perils of Projections

Average remaining extent gain in the last 10 years would result in a maximum of 24.73 million km2, 2nd lowest but still 1.09 million above the extraordinary 2016 year (of which Oct-Nov were the most extraordinary).
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gerontocrat · « **Reply #653 on:** September 19, 2019, 05:04:45 PM »

JAXA Global Sea Ice Extent as at 18 September 2019 : 22,191,387 km2

A bit more...

I attach the graph for the entire year. Makes it obvious that 2019 was not a good year for the cryosphere

The Perils of Projections I also attach the plume of projections. In the last 10 years the remaining extent gain over the last 7 weeks or so to maximum gives a range of maxima between 23.5 and 25.5 million km2, a range of 2 million.

gerontocrat · « **Reply #654 on:** September 20, 2019, 12:02:53 PM »

JAXA Global Sea Ice Extent as at 18 September 2019 : 22,149,418 km2

Extent continues to drop, even as "the norm" returns to extent increases to the November max.

- On this day Global extent lowest again, making 120 days in 2019 at lowest,
- extent 157 k below 2016, & 274 k below 2018.
- extent gain from the March minimum to date is 5.90 million km2, 0.61 million km2 (9.3%) less than the average gain of 6.51 million km2 by this day,
-on average 72.1% of extent gain done and 46 days to the average date of maximum in early November.

The Perils of Projections

Average remaining extent gain in the last 10 years would result in a maximum of 24.66 million km2, 2nd lowest but still 1.03 million above the extraordinary 2016 year (of which Oct-Nov were the most extraordinary).
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gerontocrat · « **Reply #655 on:** September 25, 2019, 09:30:15 AM »

JAXA Global Sea Ice Extent as at 24 September 2019 : 22,497,025 km2

In the last week strong Arctic extent gains and Antarctic gains after the usual date of maximum. The result is large gains in Global Sea Ice extent.

- On this day Global extent 2nd lowest again, after 124 days at lowest in 2019 ,
- extent 185 k above 2017,
- extent gain from the March minimum to date is 6.25 million km2, 0.46 million km2 (6.8%) less than the average gain of 6.70 million km2 by this day,
-on average 74.3% of extent gain done and 41 days to the average date of maximum in early November.

The Perils of Projections

Average remaining extent gain in the last 10 years would result in a maximum of 24.82 million km2, 2nd lowest but 1.18 million above the extraordinary 2016 year (of which Oct-Nov were the most extraordinary).
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gerontocrat · « **Reply #656 on:** September 29, 2019, 01:18:49 PM »

JAXA Global Sea Ice Extent as at 28 September 2019 : 22,654,391 km2

Just several days of below average Arctic extent gains, and just one day (28 Sep) of Antarctic extent loss sees Global Extent back at lowest in the satellite record (by a smidgeon).

- On this day Global extent lowest again, 125 days at lowest in 2019 ,
- extent 25 k below 2017,
- extent gain from the March minimum to date is 6.41 million km2, 0.51 million km2 (7.4%) less than the average gain of 6.92 million km2 by this day,
-on average 76.7% of extent gain done and 37 days to the average date of maximum in early November.

The Perils of Projections

Average remaining extent gain in the last 10 years would result in a maximum of 24.76 million km2, 2nd lowest but 1.12 million above the extraordinary 2016 year (of which Oct-Nov were the most extraordinary).
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gerontocrat · « **Reply #657 on:** October 01, 2019, 01:56:07 PM »

JAXA Global Sea Ice Extent as at 28 September 2019 : 22,732,560 km2

Jaxa Global Extent stays at lowest in the satellite record (by a smidgeon).

- On this day Global extent lowest again, 126 days at lowest in 2019 ,
- extent 49 k below 2017,
- extent gain from the March minimum to date is 6.48 million km2, 0.53 million km2 (7.5%) less than the average gain of 7.01 million km2 by this day,
-on average 77.7% of extent gain done and 35 days to the average date of maximum in early November.

The Perils of Projections

Average remaining extent gain in the last 10 years would result in a maximum of 24.75 million km2, 2nd lowest but 1.11 million above the extraordinary 2016 year (of which Oct-Nov were the most extraordinary).
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gerontocrat · « **Reply #658 on:** October 01, 2019, 02:02:00 PM »

JAXA Global Sea Ice Extent as at 28 September 2019 : 22,732,560 km2

The Perils of Projections (continued)

The graph attached shows the 2+ million km2 spread of projected maxima for the last 30 days or so of Global Sea Ice extent remaining gain in the last 10 years.

Stephan · « **Reply #659 on:** October 05, 2019, 08:30:05 PM »

JAXA Global Sea Ice Extent
is still lowest on Oct 4, 2019
ranking list (values in M km²)
2019 22.75
2018 22.80
2012 22.97
2016 23.08
2017 23.10
2007 23.27
2008 23.55
2011 23.67
2010s ave 23.69
2015 23.86
2009 24.40

On the other end of the list you find the "early" years:
1980 27.23
1981 27.12
1988 27.09

gerontocrat · « **Reply #660 on:** October 06, 2019, 01:59:19 PM »

JAXA Global Sea Ice Extent as at 5 October 2019 : 22,779,042 km2

Despite Antarctic Sea Ice losses at a near standstill, well below average Arctic Sea Ice extent ~~loss~~ GAIN results in Jaxa Global Extent staying at lowest in the satellite record (by a smidgeon). That's for 132 days this year.

- extent 58 k below 2018, 251 k below 2012.
- extent gain from the March minimum to date is 6.53 million km2, 0.69 million km2 (9.5%) less than the average gain of 7.22 million km2 by this day,
-on average 80.0% of extent gain done and 30 days to the average date of maximum in early November.

The Perils of Projections

Average remaining extent gain in the last 10 years would result in a maximum of 24.59 million km2, 2nd lowest but 0.95 million above the extraordinary 2016 year (of which Oct-Nov were the most extraordinary).

If, a big if, Arctic re-freeze continues to be very slow, and Antarctic extent loss speeds up to average, 2019 will give 2016 a run for its money for the remaining 30 days to maximum.
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ps: Global Sea Ice Extent on my birthday was 3.8 million km2 less than the 1980's average. That is 15 times the area of the UK. That is a lot of open water where that used to be covered with ice.

gerontocrat · « **Reply #661 on:** October 09, 2019, 12:56:56 PM »

JAXA Global Sea Ice Extent as at 8 October 2019 : 22,839,582 km2

Despite Antarctic Sea Ice losses continuing at a near standstill, greatly below average Arctic Sea Ice extent gain results in Jaxa Global Extent staying at lowest in the satellite record (by an even smaller smidgeon). That's lowest for 135 days this year.

- extent 20 k below 2018, 105 k below 2012.
- extent gain from the March minimum to date is 6.59 million km2, 0.79 million km2 (10.8%) less than the average gain of 7.38 million km2 by this day,
-on average 81.8% of extent gain done and 27 days to the average date of maximum in early November.

The Perils of Projections

Average remaining extent gain in the last 10 years would result in a maximum of 24.48 million km2, 2nd lowest but 0.84 million above the extraordinary 2016 year (of which Oct-Nov were the most extraordinary).

If, a big if, Arctic re-freeze continues to be very slow, and Antarctic extent loss speeds up to average, 2019 will give 2016 a run for its money for the remaining 4 weeks to maximum.
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gerontocrat · « **Reply #662 on:** October 10, 2019, 11:46:23 AM »

JAXA Global Sea Ice Extent as at 8 October 2019 : 22,792,219 km2

An Antarctic Sea Ice loss above average and an Arctic Sea Ice extent loss results in Jaxa Global Extent staying at lowest in the satellite record by a greater amount. That's lowest for 136 days this year.

- extent loss 47k, 118k less than the average GAIN of 71 k.
- extent 74 k below 2018, 229k below 2016, 439 k below 2012.
- extent gain from the March minimum to date is 6.54 million km2, 0.91 million km2 (12.2%) less than the average gain of 7.46 million km2 by this day,
-on average 82.6% of extent gain done and 26 days to the average date of maximum in early November.

The Perils of Projections

Average remaining extent gain in the last 10 years would result in a maximum of 24.36 million km2, 2nd lowest but 0.72 million above the extraordinary 2016 year (of which Oct-Nov were the most extraordinary).

If, a big if, Arctic re-freeze continues to be very slow, and Antarctic extent loss speeds up to average, 2019 will give 2016 a run for its money for the remaining 4 weeks to maximum.

In any event, it is likely that 2019 data will continue to draw the line on the unused part of the graph paper for a week or two longer. (another hostage to fortune)
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GoSouthYoungins · « **Reply #663 on:** October 11, 2019, 08:19:54 AM »

winning

(I hate it when we aren't in first.)

gerontocrat · « **Reply #664 on:** October 14, 2019, 02:18:24 PM »

JAXA Glhttps://forum.arctic-sea-ice.net/Themes/smf-curve1/images/bbc/img.gifobal Sea Ice Extent as at 13 October 2019 : 23,017,011 km2

Antarctic Sea Ice has stalled in the last 3 days. But well below average Arctic Sea Ice extent gain results in Jaxa Global Extent staying at lowest in the satellite record. That's lowest for 140 days this year.

- extent gain in the last 4 days 225k, 20k less than the average gain of 245 k.
- extent 228 k below 2018, 158 k below 2016, 514 k below 2012.
- extent gain from the March minimum to date is 6.77 million km2, 0.93 million km2 (12.1%) less than the average gain of 7.70 million km2 by this day,
-on average 85.4% of extent gain done and 22 days to the average date of maximum in early November.

The Perils of Projections

Average remaining extent gain in the last 10 years would result in a maximum of 24.34 million km2, 2nd lowest but 0.70 million above the extraordinary 2016 year (of which Oct-Nov were the most extraordinary).

If, a big if, Arctic re-freeze continues to be very slow, and Antarctic extent loss speeds up to average, 2019 will give 2016 a run for its money for the remaining 4 weeks to maximum.

In any event, it is likely that 2019 data will continue to draw the line on the unused part of the graph paper for a few days more. (another hostage to fortune)
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gerontocrat · « **Reply #665 on:** October 18, 2019, 12:53:23 PM »

JAXA Global Sea Ice Extent as at 17 October 2019 : 23,212,444 km2

Antarctic Sea Ice loss in the last 4 days was below average overall, so despite well below average Arctic Sea Ice extent gain, Jaxa Global Extent on this day has surrendered 1st lowest to 2016. On this day 2019 Global extent a mere 20k, (0.1%) above 2016.

That's ended a run of lowest for 143 days this year.

- extent 311 k below 2018, 1,071 k below 2012, 1,661k below the 2010's average, 20 k above 2016,
- extent gain from the March minimum to date is 6.96 million km2, 1.07 million km2 (13.3%) less than the average gain of 8.03 million km2 by this day,
-on average 89.0% of extent gain done and 18 days to the average date of maximum in early November.

The Perils of Projections

Average remaining extent gain in the last 10 years would result in a maximum of 24.20 million km2, 2nd lowest but 0.57 million above the extraordinary 2016 year (of which Oct-Nov were the most extraordinary).

If, a big if, Arctic re-freeze returns to very much below average, and Antarctic extent loss speeds up to average, 2019 will give 2016 a run for its money for the remaining few days to maximum.
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gerontocrat · « **Reply #666 on:** October 22, 2019, 02:57:46 PM »

JAXA Global Sea Ice Extent as at 21 October 2019 : 23,501,941 km2

Antarctic Sea Ice loss in the last 4 days was above average overall, but at or above above average Arctic Sea Ice extent gain, ,means Jaxa Global Extent remains 2nd lowest to 2016.

- extent 185 k below 2018, 1,481 k below 2012, 1,689 k below the 2010's average, 63 k above 2016,
- extent gain from the March minimum to date is 7.25 million km2, 1.05 million km2 (13.1%) less than the average gain of 8.35 million km2 by this day,
-on average 92.5 % of extent gain done and just 14 days to the average date of maximum in early November.

The Perils of Projections

Average remaining extent gain in the last 10 years would result in a maximum of 24.18 million km2, 2nd lowest but 0.54 million above the extraordinary 2016 year (of which Oct-Nov were the most extraordinary).

If, a big if, Arctic re-freeze returns to very much below average, and Antarctic extent loss speeds up to average, 2019 will give 2016 a run for its money for the remaining few days to maximum.
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Aluminium · « **Reply #667 on:** October 23, 2019, 04:42:05 PM »

The lowest since 2016.

Stephan · « **Reply #668 on:** October 24, 2019, 10:43:20 PM »

I doubt that the Global Sea Ice (extent or area) anomaly will ever recover back to the normal (0 sigma) line.

GoSouthYoungins · « **Reply #669 on:** October 25, 2019, 04:13:35 PM »

Down, down it goes, where it stops, no one know.

We are currently about 10 days out from max anomaly. Very exciting. It will be close to 2016 but will it beat it?!? Fingers crossed.

gerontocrat · « **Reply #670 on:** October 26, 2019, 02:34:13 PM »

JAXA Global Sea Ice Extent as at 25 October 2019 : 23,789,958 km2

Antarctic Sea Ice loss in the last week was above average overall, but at or above or very much above average Arctic Sea Ice extent gain, means Jaxa Global Extent remains 2nd lowest, increasingly above 2016 extent.

- extent 282k below 2018, 1,412 k below 2012, 1,638 k below the 2010's average, 291 k above 2016,
- extent gain from the March minimum to date is 7.54 million km2, 1.04 million km2 (12.1%) less than the average gain of 8.58 million km2 by this day,
-on average 95.0 % of extent gain done and just 10 days to the average date of maximum in early November.

The Perils of Projections

Average remaining extent gain in the last 10 years would result in a maximum of 24.24 million km2, 2nd lowest but 0.60 million above the extraordinary 2016 year (of which Oct-Nov were the most extraordinary).

My bet is on 2016 remaining 1st lowest for some considerable time.
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Stephan · « **Reply #671 on:** October 26, 2019, 10:02:43 PM »

Except for the years 2013 and 2014 all other years of this decade are in the "top ten lowest" list...

gerontocrat · « **Reply #672 on:** October 28, 2019, 11:58:16 AM »

JAXA Global Sea Ice Extent as at 27 October 2019 : 24,127,262 km2

Antarctic Sea Ice loss in the last week was above average overall, but at or above and extremely above average Arctic Sea Ice extent gain, means Jaxa Global Extent remains 2nd lowest, increasingly above 2016 extent.

- extent 317 k below 2018, 1,064 k below 2012, 1,399 k below the 2010's average, 594 k above 2016,
- extent gain from the March minimum to date is 7.88 million km2, 0.82 million km2 (9.4%) less than the average gain of 8.70 million km2 by this day,
-on average 96.4 % of extent gain done and just 8 days to the average date of maximum in early November.

The Perils of Projections

Average remaining extent gain in the last 10 years would result in a maximum of 24.45 million km2, 2nd lowest but 0.81 million above the extraordinary 2016 year (of which Oct-Nov were the most extraordinary).

My bet is on 2016 remaining 1st lowest for some considerable time. Much (including date of maximum) depends on whether Arctic extent gains remain at such elevated levels.
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Stephan · « **Reply #673 on:** October 29, 2019, 10:34:28 PM »

Quote from: gerontocrat on October 28, 2019, 11:58:16 AM

Average remaining extent gain in the last 10 years would result in a maximum of 24.45 million km2, 2nd lowest but 0.81 million above the extraordinary 2016 year (of which Oct-Nov were the most extraordinary).

My bet is on 2016 remaining 1st lowest for some considerable time. Much (including date of maximum) depends on whether Arctic extent gains remain at such elevated levels.

2016 has already defended its outstanding #1 in global sea ice maximum as 2019 has passed it by.

gerontocrat · « **Reply #674 on:** October 30, 2019, 01:10:39 PM »

JAXA Global Sea Ice Extent as at 29 October 2019 : 24,326,153 km2

Antarctic Sea Ice loss in the last week continues above average overall, but above and extremely above average Arctic Sea Ice extent gain, means Jaxa Global Extent remains 2nd lowest, increasingly greatly above 2016 extent.

- extent 204 k below 2018, 913 k below 2012, 1,215 k below the 2010's average, 883 k above 2016,
- extent gain from the March minimum to date is 8.08 million km2, 0.67 million km2 (7.7%) less than the average gain of 8.75 million km2 by this day,
-on average 97.4 % of extent gain done and just 6 days to the average date of maximum in early November.

The Perils of Projections

Average remaining extent gain in the last 10 years would result in a maximum of 24.56 million km2, 2nd lowest but 0.92 million above the extraordinary 2016 year (of which Oct-Nov-Dec were the most extraordinary). My bet is on 2016 remaining 1st lowest for some considerable time.

The date of maximum depends very much on whether Arctic extent gains remain at such elevated levels. If yes, the maximum would be delayed (unless very high Antarctic sea ice loss)
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roger white · « **Reply #675 on:** October 31, 2019, 10:35:12 AM »

Just running over the latest global sea ice figures as we are close to the end of the freezing season (?) & also near the end of the 2010's decade.

Your decadal figures show:

Global sea ice extent loss ( averages 1980's-2010's) of 6%...or 1.5% loss per decade...( not evenly of course).

Do we have any idea of the shrinkage of expansion of global sea ice in other time frames - ie
1800's-1840's...1900's-1940's......etc to see if this kind of change is unusual?

gerontocrat · « **Reply #676 on:** November 01, 2019, 12:01:05 PM »

Quote from: roger white on October 31, 2019, 10:35:12 AM

Do we have any idea of the shrinkage of expansion of global sea ice in other time frames - ie
1800's-1840's...1900's-1940's......etc to see if this kind of change is unusual?

For the Arctic, maybe; for the Antarctic, probably not. When it comes to the cryosphere, Antarctica is the place we need to know about the most, and where we know the least.

gerontocrat · « **Reply #677 on:** November 01, 2019, 12:07:56 PM »

JAXA Global Sea Ice Extent as at 31 October 2019 : 24,512,836 km2

Antarctic Sea Ice loss in the last week continues above average overall, but above and extremely above average Arctic Sea Ice extent gains, means Jaxa Global Extent remains 2nd lowest, increasingly greatly above 2016 extent.

- extent 151 k below 2018, 884 k below 2012, 1,112 k below the 2010's average, 1,082 k above 2016,
- extent gain from the March minimum to date is 8.26 million km2, 0.57 million km2 (6.4%) less than the average gain of 8.83 million km2 by this day,
-on average 98.3 % of extent gain done and just 4 days to the average date of maximum in early November.

Still A Perilous Projection at this late date

Average remaining extent gain in the last 10 years would result in a maximum of 24.67 million km2, 2nd lowest but 1.03 million above the extraordinary 2016 year (of which Oct-Nov-Dec were the most extraordinary). My bet is on 2016 remaining 1st lowest for some considerable time.

The date of maximum depends very much on whether Arctic extent gains remain at such elevated levels. If yes, the maximum would be delayed (unless very high Antarctic sea ice loss)
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gerontocrat · « **Reply #678 on:** November 02, 2019, 01:20:59 PM »

JAXA Global Sea Ice Extent as at 1 November 2019 : 24,586,979 km2

Antarctic Sea Ice loss continues at above average, but very much above average Arctic Sea Ice extent gains means Jaxa Global Extent remains 2nd lowest, increasingly greatly above 2016 extent.

- extent 178 k below 2018, 833 k below 2012, 1,109 k below the 2010's average, 1,106 k above 2016,
- extent gain from the March minimum to date is 8.34 million km2, 0.56 million km2 (6.3%) less than the average gain of 8.90 million km2 by this day,
-on average 99.2 % of extent gain done and just 3 days to the average date of maximum on 4th November.

Still A Perilous Projection at this late date

Average remaining extent gain in the last 10 years would result in a maximum of 24.66 million km2, 2nd lowest but 1.02 million above the extraordinary 2016 year (of which Oct-Nov-Dec were the most extraordinary). My bet is that it is a racing certainty that 2016 remains lowest for some considerable time.

The date of maximum depends very much on whether Arctic extent gains remain at such elevated levels. If yes, the maximum will be delayed (unless very high Antarctic sea ice loss)
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gerontocrat · « **Reply #679 on:** November 03, 2019, 03:00:35 PM »

JAXA Global Sea Ice Extent as at 2 November 2019 : 24,600,328 km2

On this day Antarctic Sea Ice loss very much above average, and Arctic Sea Ice extent gain moderated but still above average . Jaxa Global Extent increased below average for a change.

- extent 285 k below 2018, 869 k below 2012, 1,127 k below the 2010's average, 1,030 k above 2016,
- extent gain from the March minimum to date is 8.35 million km2, 0.38 million km2 (6.5%) less than the average gain of 8.94 million km2 by this day,
-on average 99.6 % of extent gain done and just 2 days to the average date of maximum on 4th November.

Still A Perilous Projection at this late date

Average remaining extent gain in the last 10 years would result in a maximum of 24.63 million km2, 2nd lowest but 0.99 million km2 above the extraordinary 2016 year (of which Oct-Nov-Dec were the most extraordinary). My bet is that it is a racing certainty that 2016 remains lowest for some considerable time.

Note:- The projection table JAXA-AA1.png attached is not fairly useless as some years are already past the maximum.

The date of maximum depends very much on whether Arctic extent gains remain at elevated levels and /or Antarctic extent loss continues above average. The maximum could be delayed or could have happened on this day.
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gerontocrat · « **Reply #680 on:** November 04, 2019, 03:17:22 PM »

JAXA Global Sea Ice Extent as at 3 November 2019 : 24,589,070 km2

On this day Antarctic Sea Ice loss very much above average, and Arctic Sea Ice extent gain moderated (but still above average) resulted in a Global Sea Ice Extent LOSS .

- extent 377 k below 2018, 949 k below 2012, 1,149 k below the 2010's average, 960 k above 2016,
- extent gain from the March minimum to date is 8.34 million km2, 0.61 million km2 (6.8%) less than the average gain of 8.95 million km2 by this day,
-on average 99.8 % of extent gain done and just 1 days to the average date of maximum on 4th November.

Still A Perilous Projection at this late date

This day saw an extent loss, so the current maximum is 24.60 on 2nd November, 2nd lowest but 0.96 million km2 above the extraordinary 2016 year (of which Oct-Nov-Dec were the most extraordinary). My bet is that it is a racing certainty that 2016 remains lowest for some considerable time.

Note:- The projection table JAXA-AA1.png attached is now useless as most years are already past the maximum.

The date of maximum depends very much on whether Arctic extent gains remain at elevated levels and /or Antarctic extent loss continues above average. The maximum could be delayed or could have happened on 2nd November.
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gerontocrat · « **Reply #681 on:** November 05, 2019, 11:54:46 AM »

JAXA Global Sea Ice Extent as at 4 November 2019 : 24,546,935 km2

On this day Antarctic Sea Ice loss very much above average, and Arctic Sea Ice extent gain moderated (but still above average) resulted in a Global Sea Ice Extent LOSS for a second day.

Therefore it may well be that the maximum was 24.60 million km2 on the 2nd November

- extent 456 k below 2018, 978 k below 2012, 1,164 k below the 2010's average, 1,009 k above 2016,
- extent gain from the March minimum to date is 8.30 million km2, 0.63 million km2 (6.8%) less than the average gain of 8.93 million km2 by this day,
-on average 100% of extent gain done and ZERO days to the average date of maximum on 4th November.

Still A Perilous Projection at this late date

This day saw an extent loss, so the current maximum is 24.60 on 2nd November, 2nd lowest but 0.96 million km2 above the extraordinary 2016 year (of which Oct-Nov-Dec were the most extraordinary). My bet is that it is a racing certainty that 2016 remains lowest for some considerable time.

Note:- The projection table JAXA-AA1.png attached is now useless as most years are already past the maximum and there is a good chance the maximum is passed.

The date of maximum depends very much on whether Arctic extent gains remain at elevated levels and /or Antarctic extent loss continues above average. The maximum could be delayed or could have happened on 2nd November.
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[/quote]

Stephan · « **Reply #682 on:** November 05, 2019, 10:16:23 PM »

Has the maximum been reached?
An increase of 0.05 M km² or more is needed.
I analyzed all JAXA graphs from 1978-2018 to find out which of the past years showed an increase of global sea ice extent from Nov 04 on of more than 0.04 M km². Out of the 41 years that happened in 10 years. Other years declined from that date on, but showed a re-increase of more than 0.04 M km² somewhen later in November. Out of the 41 years that happened in 11 years. Based on that the chance is 21:41 (or roughly 50%) that we have already passed the annual maximum. I think this week will show whether this will come true.

gerontocrat · « **Reply #683 on:** November 06, 2019, 02:01:16 PM »

JAXA Global Sea Ice Extent as at 5 November 2019 : 24,442,455 km2

On this day Antarctic Sea Ice loss extremely above average, and Arctic Sea Ice extent gain moderated some more (but still above average) resulted in a Global Sea Ice Extent LOSS for a third day of more than a century.

Therefore it is probable that the maximum was 24.60 million km2 on the 2nd November, given that on this day extent i below the current maximum by 158k km2.

- extent 486 k below 2018, 1,128 k below 2012, 1,273 k below the 2010's average, 851 k above 2016,
-on average 100% of extent gain done and Minus 1 days to the average date of maximum on 4th November.

NOT a Perilous Projection at this late date

This day saw an extent loss, so the current maximum is 24.60 on 2nd November, 2nd lowest but 0.96 million km2 above the extraordinary 2016 year (of which Oct-Nov-Dec were the most extraordinary). My bet is that it is a racing certainty that 2016 remains lowest for some considerable time.

Note:- The projection table JAXA-AA1.png is attached for the last time, a new table for the 2020 minimum will appear soon(ish).

The date of maximum depends very much on whether Arctic extent gains remain at elevated levels and /or Antarctic extent loss continues above average. The maximum could be delayed or could have happened on 2nd November.
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gerontocrat · « **Reply #684 on:** November 07, 2019, 12:13:32 PM »

JAXA Global Sea Ice Extent as at 6 November 2019 : 24,442,455 km2

On this day Antarctic Sea Ice loss extremely above average, and Arctic Sea Ice extent gain moderated (but still above average) resulted in a Global Sea Ice Extent LOSS for a fourth day of above average.

Therefore it is more than probable that the maximum was 24.60 million km2 on the 2nd November, given that on this day extent is below the current maximum by 205k km2.

Note:- The projection table for the 2020 minimum will appear soon(ish).
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gerontocrat · « **Reply #685 on:** November 10, 2019, 01:10:41 PM »

JAXA Global Sea Ice Extent as at 9 November 2019 : 24,338,686
km2

The maximum was 24.60 million km2 on the 2nd November

Since that date
- Extent losses 0.26 million km2, 0.03 million km2 more than the average.
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gerontocrat · « **Reply #686 on:** November 11, 2019, 10:04:34 AM »

JAXA Global Sea Ice Extent as at 10 November 2019 : 24,225,279 lm2

The maximum was 24.60 million km2 on the 2nd November, and since that date..
- Extent losses 0.38 million km2, 0.12 million km2 (46%) more than the average.
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gerontocrat · « **Reply #687 on:** November 12, 2019, 06:55:11 AM »

JAXA Global Sea Ice Extent as at 10 November 2019 : 24,110,255 km2

- Extent losses from maximum 0.49 million km2, 0.18 million km2 (57%) more than the average of 0.31 million km2.
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Stephan · « **Reply #688 on:** November 15, 2019, 08:24:55 PM »

I compared the actual JAXA extent data with the averages from 1980s to 2010s.
Arctic sea ice extent of 2019 is 4 days behind schedule if compared with the 2010s average. In the Antarctic 2019 is ahead by 7 days, which sums up to 11 days of difference.
These differences are bigger in comparison with earlier decades:
2019 vs 2000s: 15 days Arctic, 8 days Antarctic = 23 days
2019 vs 1990s: 25 days Arctic, 8 days Antarctic = 33 days
2019 vs 1980s: 29 days Arctic, 9 days Antarctic = 38 days
This is a difference of more than a month!

Glen Koehler · « **Reply #689 on:** November 15, 2019, 11:15:37 PM »

Quote from: Stephan on November 15, 2019, 08:24:55 PM

I compared the actual JAXA extent data with the averages from 1980s to 2010s.
Arctic sea ice extent of 2019 is 4 days behind schedule if compared with the 2010s average. In the Antarctic 2019 is ahead by 7 days, which sums up to 11 days of difference.
These differences are bigger in comparison with earlier decades:
2019 vs 2000s: 15 days Arctic, 8 days Antarctic = 23 days
2019 vs 1990s: 25 days Arctic, 8 days Antarctic = 33 days
2019 vs 1980s: 29 days Arctic, 9 days Antarctic = 38 days
This is a difference of more than a month!

That is an interesting way to capture the trend Stephan. Perhaps we can compare the invidual decadal rates by subtracting each one from the previous decade. (I think but not sure this is kosher.)
Thus 1990s vs. 1980s: 5 more days
2000s vs. 1990s: 10 more days
2010s vs. 2000s: 23 more days
2020s vs. 2010s: 46 more?? more days (since there a doubling for each previous step)
Just a wild guess. There may be constraints on continued growth at a doubling every decade.

The Arctic-only version:
1990s vs. 1980s: 4 more days
2000s vs. 1990s: 10 more days
2010s vs. 2000s: 15 more days
2020s vs. 2010s: 20 more?? (since each prior step added about 5 days)

The Antarctic-only version:
1990s vs. 1980s: 1 more day
2000s vs. 1990s: 0 more days
2010s vs. 2000s: 8 more days
2020s vs. 2010s: 8 more?? (since previous step added 8 days)

At first glance, you might think that the big difference in the Arctic vs. Antarctic trends shows a problem with using this method. But I think it reflects an actual characteristic of the data. In the 1980s and 1990s, the Antarctic sea ice was not showing a trend from global warming.

I'm surprised that the Antarctic 2010s vs 2000s even showed an increase because I thought it was only in the last few years that Antarctic sea ice Extent was declining. (or am I completely misunderstanding the dates Stephan is citing for Antarctic sea ice?)

That possible rapid acceleration for the Arctic looks worrisome. Good thing we have smart and wise political leadership at the helm to steer us through what could be a time of difficult choices and profound but necessary changes to reduce the harm.
What... we don't have that? Uh oh.

Stephan · « **Reply #690 on:** November 16, 2019, 09:40:50 AM »

Just a small correction to your table:
"Thus 1990s vs. 1980s: 5 more days
2000s vs. 1990s: 10 more days
2010s vs. 2000s: 12 more days"
as the difference between 2019 / 2010s vs. 2019 / 2000s is 12 days larger.
Therefore the "doubling" each decade can't be confirmed.

Concerning Antarctic Sea Ice extent:
The increase from decade to decade, as it had been evaluated years ago is not valid for mid November. On Nov 15 the decadal averages are:
1980s: 16.11 M km²
1990s: 15.99 M km²
2000s: 16.06 M km²
2010s: 15.88 M km²
With daily changes of 0.10 to 0.18 M km² these differences are statistically negligible.

gerontocrat · « **Reply #691 on:** November 16, 2019, 04:50:43 PM »

JAXA Global Sea Ice Extent as at 15 November 2019 : 23,984,246 km2

- In 3 of the last 4 days extent loss well below average,
- Extent losses from maximum 0.62 million km2, 0.05 million km2 (10%) more than the average of 0.57 million km2.
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gerontocrat · « **Reply #692 on:** November 21, 2019, 11:50:56 AM »

JAXA GLOBAL SEA ICE EXTENT :- 23,790,35 km2（November 20, 2019）

- 2019 is 3rd lowest in the satellite record since 1979,
- Extent loss on this day 105 k, 32 k more than the last 10 years' average of 73 k,
- Extent loss to date 0.81 million km2, 0.12 million (13%) less than the 10 year average of 0.93 million km2 by this day.
- Extent is 2.15 million km2 greater than 2016 due to extremely low extent in both the Arctic and Antarctic at this time,
- 10.2 % of the average ice loss of the season done, with on average 86 days to the average minimum date of 13 Feb.

The Perils of Projections

Still extremely / ridiculously early to take this seriously. Average melt from this date would produce a minimum of 15.62 million km2, 0.07 million more than the record low in early 2018.
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gerontocrat · « **Reply #693 on:** November 24, 2019, 04:01:28 PM »

JAXA GLOBAL SEA ICE EXTENT :- 23,566,742 km2（November 23, 2019）

- 2019 is 3rd lowest in the satellite record since 1979,
- Extent loss on this day 76 k, 49 k more than the last 10 years' average of 26 k,
- Extent loss to date 1.03 million km2, 0.02 million (2%) less than the 10 year average of 1.05 million km2 by this day.
- Extent is 1.85 million km2 greater than 2016,
- 11.6 % of the average ice loss of the season done, with on average 83 days to the average minimum date of 13 Feb.

The Perils of Projections

Still extremely / ridiculously early to take this seriously. Average melt from this date would produce a minimum of 15.51 million km2, 0.04 million less than the record low in early 2018.
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Stephan · « **Reply #694 on:** November 28, 2019, 06:53:47 PM »

I compared the actual JAXA extent data with the averages from 1980s to 2010s.
Arctic sea ice extent of 2019 is 4 days behind schedule if compared with the 2010s average. In the Antarctic 2019 is ahead by 6 days, which sums up to 10 days of difference.
These differences are bigger in comparison with earlier decades:
2019 vs 2000s: 13 days Arctic, 5 days Antarctic = 18 days
2019 vs 1990s: 24 days Arctic, 5 days Antarctic = 29 days
2019 vs 1980s: 29 days Arctic, 6 days Antarctic = 35 days
This is a difference of more than a month!

gerontocrat · « **Reply #695 on:** November 29, 2019, 02:09:30 PM »

JAXA GLOBAL SEA ICE EXTENT :- 23,087,306 km2（November 28, 2019）

- 2019 is 2nd lowest in the satellite record since 1979,
- Extent loss on this day 39 k, 52 k less than the last 10 years' average of 91 k,
- Extent loss to date 1.51 million km2, 0.12 million (8.9 %) more than the 10 year average of 1.39 million km2 by this day.
- Extent is 1.51 million km2 greater than 2016,
- 15.2 % of the average ice loss of the season done, with on average 78 days to the average minimum date of 13 Feb.

The Perils of Projections

Still extremely / ridiculously early to take this seriously. Average melt from this date would produce a minimum of 15.37 million km2, 0.18 million less than the record low in early 2018.
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gerontocrat · « **Reply #696 on:** December 03, 2019, 12:01:43 PM »

JAXA GLOBAL SEA ICE EXTENT :- 22,695,082 km2（December 2, 2019）

- 2019 is 2nd lowest in the satellite record since 1979,
- Extent loss on this day 115 k, 1 k more than the last 10 years' average of 114 k,
- Extent loss to date 1.91 million km2, 0.11 million (6.0 %) more than the 10 year average of 1.80 million km2 by this day.
- Extent is 1.48 million km2 greater than 2016,
- 19.7 % of the average ice loss of the season done, with on average 74 days to the average minimum date of 13 Feb.

The Perils of Projections

Still extremely / ridiculously early to take this seriously. Average melt from this date would produce a minimum of 15.39 million km2, 0.16 million less than the record low in early 2018.
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gerontocrat · « **Reply #697 on:** December 04, 2019, 06:47:15 AM »

JAXA GLOBAL SEA ICE EXTENT :- 22,527,955 km2（December 3, 2019）

- 2019 is 2nd lowest in the satellite record since 1979,
- Extent loss on this day 167 k, 52 k more than the last 10 years' average of 115 k,
- Extent loss to date 2.07 million km2, 0.16 million (8.2 %) more than the 10 year average of 1.91 million km2 by this day.
- Extent is 1.53 million km2 greater than 2016,
- 21.0 % of the average ice loss of the season done, with on average 73 days to the average minimum date of 13 Feb.

The Perils of Projections

Still extremely early to take this seriously. Average melt from this date would produce a minimum of 15.33 million km2, 0.22 million less than the record low in early 2018.
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gerontocrat · « **Reply #698 on:** December 05, 2019, 10:58:57 AM »

JAXA GLOBAL SEA ICE EXTENT :- 22,420,949 km2（December 4, 2019）

- 2019 is 2nd lowest in the satellite record since 1979,
- Extent loss on this day 107 k, 25 k less than the last 10 years' average of 132 k,
- Extent loss to date 2.18 million km2, 0.13 million (6.5 %) more than the 10 year average of 2.05 million km2 by this day.
- Extent is 1.65 million km2 greater than 2016,
- 22.5 % of the average ice loss of the season done, with on average 72 days to the average minimum date of 13 Feb.

The Perils of Projections

Still extremely early to take this seriously. Average melt from this date would produce a minimum of 15.36 million km2, 0.19 million less than the record low in early 2018.
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gerontocrat · « **Reply #699 on:** December 09, 2019, 08:04:12 AM »

JAXA GLOBAL SEA ICE EXTENT :- 22,042,280 km2（December 8, 2019）

Above average Antarctic extent loss more than matched by extreme Arctic extent gains.

- 2019 is 2nd lowest in the satellite record since 1979,
- Extent loss on this day 110 k, 37 k less than the last 10 years' average of 147 k,
- Extent loss to date 2.56 million km2, 0.03 million (1.0 %) more than the 10 year average of 2.53 million km2 by this day.
- Extent is 1.82 million km2 greater than 2016,
- 27.8 % of the average ice loss of the season done, with on average 68 days to the average minimum date of 13 Feb.

The Perils of Projections

Still extremely early to take this seriously. Average melt from this date would produce a minimum of 15.47 million km2, 0.08 million less than the record low in early 2018.
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