Antarctic Sea Ice Extent and Area

[Stephan]

Have we already seen the 2021 maximum JAXA Antarctic Sea Ice Extent on August 30 (18.72 M km²)? Probably yes.

I evaluated the JAXA data to find out whether an increase from Sep 15 until the individual maximum* has been higher than 0.30 M km² (→ maximum will be reached later), between 0.26 and 0.30 M km² (→ undecided) or below 0.26 M km² (→ we are already in the melting season). I grouped the results into several decades (the numbers give the number of years for which each individual result is applicable).

                      > 0.30 M km²    0.26-0.30 M km²  < 0.26 M km²
1979-1989            1                       0                         10
1990-1999            1                       0                           9
2000-2009            3                       0                           7
2010-2020            2                       0                           9
sum                      7 (17%)            0 (0%)                 35 (83%)

* For the years in which the maximum has already passed I evaluated against the increase from today until the second maximum (1979, 1982, 1985, 1992, 1994, 2002, 2004, 2008, 2010, 2016, 2017)

[gerontocrat]

JAXA ANTARCTIC SEA ICE EXTENT:  18,437,159 KM2 as at 15-Sep-2021

- Extent loss on this day 94k, 111 k less than the average gain on this day (of the last 10 years) of 17k,
- Extent gain from minimum on this date is 15.65 million km2, 0.09 million km2, -(0.5%) less than the 10 year average of 15.73 million km2.
- Extent is 16th lowest, 28th highest, in the 43 year satellite record of which 6 lower values are in the years before 2000

- Extent is  276 k MORE than 2015
- Extent is  509 k MORE than 2017
- Extent is  592 k LESS than 2006
- Extent is  424 k LESS than 2020
- Extent is  135 k LESS than the 1980's Average
- Extent is  142 k LESS than the 2010's Average

- On average  98.5% of ice gain from minimum to maximum done, and 7 days to maximum

Projections. (Table JAXA-Ant1)

Sea ice extent is falling like a stone when it should be increasing.
Extent has changed from 25th lowest to 16th lowest in the last 3 days.

Stephan's analysis shows it is likely that the maximum was reached on the 30th August at 18.72 million km2. This is 10 days earlier than the earliest date this century and 3 weeks earlier than the average date of the last 10 years.
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Click on image  for full-size

[gerontocrat]

JAXA Extent data - 365 day Trailing Average

In the last 25 days the 365 average has switched from a gain of 1,000 km2 per day to a reduction of 1,000 km2 per day. This is simply due to sea ice extent in 2021 at first growing slowly and then recently reducing, while in 2020 sea ice extent increased. On the 21 Aug 2021 extent was more than 300k above that of 2020, by 15th September 2021 extent is more than 400k km2 less than 2020.

[Stephan]

Have we already seen the 2021 maximum JAXA Antarctic Sea Ice Extent on August 30 (18.72 M km²)? Almost certain.

I evaluated the JAXA data to find out whether an increase from Sep 16 until the individual maximum* has been higher than 0.36 M km² (→ maximum will be reached later), between 0.32 and 0.36 M km² (→ undecided) or below 0.32 M km² (→ we are already in the melting season). I grouped the results into several decades (the numbers give the number of years for which each individual result is applicable).

                      > 0.36 M km²    0.32-0.36 M km²  < 0.32 M km²
1979-1989            0                       0                         11
1990-1999            0                       1                           9
2000-2009            2                       0                           8
2010-2020            1                       1                           9
sum                      3 (7%)              2 (5%)                 37 (88%)

* For the years in which the maximum has already passed I evaluated against the increase from today until the second maximum (1979, 1982, 1985, 1992, 1994, 1998, 2002, 2004, 2008, 2010, 2016, 2017)

[gerontocrat]

JAXA ANTARCTIC SEA ICE EXTENT:  18,376,207 KM2 as at 16-Sep-2021

- Extent loss on this day 61k, 78 k less than the average gain on this day (of the last 10 years) of 17k,
- Extent gain from minimum on this date is 15.59 million km2, 0.16 million km2, -(1.0%) less than the 10 year average of 15.75 million km2.
- Extent is 16th lowest, 28th highest, in the 43 year satellite record of which 6 lower values are in the years before 2000

- Extent is  227 k MORE than 2015
- Extent is  462 k MORE than 2017
- Extent is  672 k LESS than 2006
- Extent is  443 k LESS than 2020
- Extent is  220 k LESS than the 1980's Average
- Extent is  218 k LESS than the 2010's Average

- On average  98.1% of ice gain from minimum to maximum done, and 6 days to maximum

Projections. (Table JAXA-Ant1)

Sea ice extent continues falling like a stone when it should be increasing.
Extent has changed from 25th lowest to 16th lowest in the last 3 days.

Stephan's analysis now shows it is very likely that the maximum was reached on the 30th August at 18.72 million km2. This day's data adds to that likelihood. This maximum is 10 days earlier than the earliest date this century and 3 weeks earlier than the average date of the last 10 years.
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Click on image  for full-size

[HapHazard]

Interesting. My memory banks are often faulty, but: does not the Antarctic ice trend kinda do the inverse of what the Arctic does, over the last 30 years or so? Forgive me for posting this offhand remark here; just got home from a 14 hour shift, I'm already on my 2nd beer, and I didn't see an Antarctic chatter thread.

Thanks as always for the work you folks do, at any rate.

Signed, a constant reader & faulty rememberer.

[Stephan]

Another loss of 0.03 M km²

Have we already seen the 2021 maximum JAXA Antarctic Sea Ice Extent on August 30 (18.72 M km²)? Almost certain.

I evaluated the JAXA data to find out whether an increase from Sep 17 until the individual maximum* has been higher than 0.39 M km² (→ maximum will be reached later), between 0.35 and 0.39 M km² (→ undecided) or below 0.35 M km² (→ we are already in the melting season). I grouped the results into several decades (the numbers give the number of years for which each individual result is applicable).

                      > 0.39 M km²    0.35-0.39 M km²  < 0.35 M km²
1979-1989            0                       0                         11
1990-1999            0                       1                           9
2000-2009            1                       1                           8
2010-2020            1                       0                         10
sum                      2 (5%)              2 (5%)                 38 (90%)

* For the years in which the maximum has already passed I evaluated against the increase from today until the second maximum (1979, 1982, 1985, 1987, 1992, 1993, 1994, 1998, 2002, 2004, 2008, 2010, 2016, 2017)

[gerontocrat]

Interesting. My memory banks are often faulty, but: does not the Antarctic ice trend kinda do the inverse of what the Arctic does, over the last 30 years or so?

There is a tiny upwards linear trend of just under 2k per year in the September sea ice extent maximum  (see attached). BUT the R2 value is 0.003 - so it is basically meaningless.

In some years the reduction in the maximum coincides with a low Arctic sea ice minimum and Global sea ice extent crashes to a low. In other years the opposite happens increasing the Global sea ice, and in some years the trends work in opposite directions.

The 365 day trailing average graph shows that in recent years the ups and downs of Antarctic sea ice have become greater; this to me suggests greater instability in the complex systen that governs the waxing and waning of sea ice. But that is my speculation.

[gerontocrat]

JAXA ANTARCTIC SEA ICE EXTENT:  18,345,144 KM2 as at 17-Sep-2021

- Extent loss on this day 31k, 35 k less than the average gain on this day (of the last 10 years) of 4k,
- Extent gain from minimum on this date is 15.56 million km2, 0.20 million km2, -(1.3%) less than the 10 year average of 15.76 million km2.
- Extent is 17th lowest, 27th highest, in the 43 year satellite record of which 7 lower values are in the years before 2000

- Extent is  168 k MORE than 2015
- Extent is  498 k MORE than 2017
- Extent is  756 k LESS than 2006
- Extent is  422 k LESS than 2020
- Extent is  259 k LESS than the 1980's Average
- Extent is  256 k LESS than the 2010's Average

- On average  98.0% of ice gain from minimum to maximum done, and 5 days to maximum

Projections. (Table JAXA-Ant1)

Stephan's analysis now shows it is just about certain that the maximum was reached on the 30th August at 18.72 million km2. This day's data adds to that likelihood. This maximum is 10 days earlier than the earliest date this century and 3 weeks earlier than the average date of the last 10 years.

One more day of losses and I will take the plunge
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Click on image  for full-size

[Stephan]

An increase of 0.04 M km² has slightly reduced the probability.

Have we already seen the 2021 maximum JAXA Antarctic Sea Ice Extent on August 30 (18.72 M km²)? Almost certain.

I evaluated the JAXA data to find out whether an increase from Sep 18 until the individual maximum* has been higher than 0.35 M km² (→ maximum will be reached later), between 0.31 and 0.35 M km² (→ undecided) or below 0.31 M km² (→ we are already in the melting season). I grouped the results into several decades (the numbers give the number of years for which each individual result is applicable).

                      > 0.35 M km²    0.31-0.35 M km²  < 0.31 M km²
1979-1989            0                       0                         11
1990-1999            1                       2                           7
2000-2009            1                       0                           9
2010-2020            2                       0                           9
sum                      4 (10%)            2 (5%)                 36 (85%)

* For the years in which the maximum has already passed I evaluated against the increase from today until the second maximum (1979, 1981, 1982, 1985, 1986, 1987, 1992, 1993, 1994, 1998, 2002, 2004, 2008, 2010, 2011, 2016, 2017)

[gerontocrat]

JAXA ANTARCTIC SEA ICE EXTENT:  18,388,955 KM2 as at 18-Sep-2021

- Extent gain on this day 44k, 39 k more than the average gain on this day (of the last 10 years) of 5k,
- Extent gain from minimum on this date is 15.60 million km2, 0.16 million km2, -(1.0%) less than the 10 year average of 15.76 million km2.
- Extent is 17th lowest, 27th highest, in the 43 year satellite record of which 7 lower values are in the years before 2000

- Extent is  207 k MORE than 2015
- Extent is  575 k MORE than 2017
- Extent is  757 k LESS than 2006
- Extent is  379 k LESS than 2020
- Extent is  219 k LESS than the 1980's Average
- Extent is  215 k LESS than the 2010's Average

- On average  98.2% of ice gain from minimum to maximum done, and 5 days to maximum

Projections. (Table JAXA-Ant1)

Average remaining freeze (of the last 10 years) would produce a maximum in Sept 2021 of 18.72 million km2, 0.65 million km2 above the 2017 record low maximum of 18.06 million km2.
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Was the large sea ice extent increase on this day a blip, or will there be another large end of season wobble in an upward direction?
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Click on image  for full-size

[gerontocrat]

NSIDC ANTARCTIC SEA ICE AREA:  14,154,162 KM2 as at 18-Sep-2021

- Area loss on this day 142k, 162 k less than the average gain on this day (of the last 10 years) of 20k,
- Area gain from minimum on this date is 12.62 million km2, 0.18 million km2, 1.4%, less than the 10 year average of 12.80 million km2.
- Area is 8th lowest in the satellite record of which 2 lower values are in the years before 2000

- Area is  41 k LESS than 2015
- Area is  310 k MORE than 2017
- Area is  1,137 k LESS than 2006
- Area is  968 k LESS than 2020
- Area is  366 k LESS than the 1980's Average

- On average  96.8% of ice gain from minimum to maximum done, and 6 days to maximum

Projections. (Table NSIDC-Area1)

Average remaining freeze (of the last 10 years) would produce a maximum in Sept 2020 of 15.16 million km2, 1.00 million km2 above the 2017 record low maximum of 14.16 million km2.
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NSIDC Sea Ice Area has collapsed to an even higher degree than has sea ice extent. Since the 29th August, sea ice area has declined by 1 million km2.

It is now highly likely, almost certain, that the 2021 sea ice area maximum ocurred on the 29th August at 15.16 million km2. This is 32nd lowest, 12th highest in the 43 year satellite record, and 3 weeks earlier than the average date of maximum in the last 10 years.

Note how the 1 million km2 of sea ice area losses in a period of usual sea ice gain has switched this to 8th lowest, 36th highest on this day.
___________________________________________________________
Click on image  for full-size, then for the maxima table click maximise for a full view

[Stephan]

Another loss of 0.04 M km²

Have we already seen the 2021 maximum JAXA Antarctic Sea Ice Extent on August 30 (18.72 M km²)? Almost certain.

I evaluated the JAXA data to find out whether an increase from Sep 19 until the individual maximum* has been higher than 0.39 M km² (→ maximum will be reached later), between 0.35 and 0.39 M km² (→ undecided) or below 0.35 M km² (→ we are already in the melting season). I grouped the results into several decades (the numbers give the number of years for which each individual result is applicable).

                      > 0.39 M km²    0.35-0.39 M km²  < 0.35 M km²
1979-1989            0                       0                         11
1990-1999            1                       0                           9
2000-2009            0                       1                           9
2010-2020            1                       0                         10
sum                      2 (5%)              1 (2%)                 39 (93%)

* For the years in which the maximum has already passed I evaluated against the increase from today until the second maximum (1979, 1981, 1982, 1985, 1986, 1987, 1992, 1993, 1994, 1995, 1998, 2002, 2004, 2008, 2010, 2011, 2016, 2017)

[gerontocrat]

JAXA ANTARCTIC SEA ICE EXTENT:  18,353,322 KM2 as at 19-Sep-2021

- Extent loss on this day 36k, 30 k less than the average loss on this day (of the last 10 years) of 6k,
- Extent gain from minimum on this date is 15.57 million km2, 0.19 million km2, -(1.2%) less than the 10 year average of 15.75 million km2.
- Extent is 14th lowest, 30th highest, in the 43 year satellite record of which 5 lower values are in the years before 2000

- Extent is  166 k MORE than 2015
- Extent is  570 k MORE than 2017
- Extent is  782 k LESS than 2006
- Extent is  403 k LESS than 2020
- Extent is  255 k LESS than the 1980's Average
- Extent is  236 k LESS than the 2010's Average

- On average  98.0% of ice gain from minimum to maximum done, and 4 days to maximum

Projections. (Table JAXA-Ant1)

Average remaining freeze (of the last 10 years) would produce a maximum in Sept 2021 of 18.72 million km2, 0.65 million km2 above the 2017 record low maximum of 18.06 million km2.
___________________________________________________________
Click on image  for full-size

[gerontocrat]

Another loss of 0.04 M km²

Have we already seen the 2021 maximum JAXA Antarctic Sea Ice Extent on August 30 (18.72 M km²)? Almost certain.

I evaluated the JAXA data to find out whether an increase from Sep 19 until the individual maximum* has been higher than 0.39 M km² (→ maximum will be reached later), between 0.35 and 0.39 M km² (→ undecided) or below 0.35 M km² (→ we are already in the melting season). I grouped the results into several decades (the numbers give the number of years for which each individual result is applicable).

                      > 0.39 M km²    0.35-0.39 M km²  < 0.35 M km²
1979-1989            0                       0                         11
1990-1999            1                       0                           9
2000-2009            0                       1                           9
2010-2020            1                       0                         10
sum                      2 (5%)              1 (2%)                 39 (93%)

* For the years in which the maximum has already passed I evaluated against the increase from today until the second maximum (1979, 1981, 1982, 1985, 1986, 1987, 1992, 1993, 1994, 1995, 1998, 2002, 2004, 2008, 2010, 2011, 2016, 2017)

The attached plume graph makes it obvious that calling the Antarctic sea ice 2021 maximum is long overdue if it was not for what happened in 2015. In that year there was a late extreme burst of sea ice extent gains from 26th September to the 1st October of 0.67 million km2 - stunning.

The Antarctic sea ice is a graveyard for forecasts and projections as this writer knows to his cost.

[oren]

Looking at what happened to area it is impossible to get extent back up to the maximum, IMHO.

[Stephan]

Another loss of 0.02 M km²

Have we already seen the 2021 maximum JAXA Antarctic Sea Ice Extent on August 30 (18.72 M km²)? Almost certain.

I evaluated the JAXA data to find out whether an increase from Sep 20 until the individual maximum* has been higher than 0.41 M km² (→ maximum will be reached later), between 0.37 and 0.41 M km² (→ undecided) or below 0.37 M km² (→ we are already in the melting season). I grouped the results into several decades (the numbers give the number of years for which each individual result is applicable).

                      > 0.41 M km²    0.37-0.41 M km²  < 0.37 M km²
1979-1989            0                       0                         11
1990-1999            0                       1                           9
2000-2009            0                       0                         10
2010-2020            1                       0                         10
sum                      1 (2%)              1 (2%)                 40 (96%)

* For the years in which the maximum has already passed I evaluated against the increase from today until the second maximum (1979, 1981, 1982, 1983, 1985, 1986, 1987, 1992, 1993, 1994, 1995, 1998, 2002, 2004, 2008, 2010, 2011, 2014, 2016, 2017)

[gerontocrat]

JAXA ANTARCTIC SEA ICE EXTENT:  18,328,455 KM2 as at 20-Sep-2021

- Extent loss on this day 25k, 48 k less than the average gain on this day (of the last 10 years) of 23k,
- Extent gain from minimum on this date is 15.54 million km2, 0.24 million km2, -(1.5%) less than the 10 year average of 15.78 million km2.
- Extent is 13th lowest, 31th highest, in the 43 year satellite record of which 5 lower values are in the years before 2000

- Extent is  99 k MORE than 2015
- Extent is  582 k MORE than 2017
- Extent is  848 k LESS than 2006
- Extent is  398 k LESS than 2020
- Extent is  267 k LESS than the 1980's Average
- Extent is  283 k LESS than the 2010's Average

- On average  97.9% of ice gain from minimum to maximum done, and 3 days to maximum

Projections. (Table JAXA-Ant1)

The maximum for 2021 is 18.72 million km2 on the 30th August, 0.65 million km2 above the 2017 record low maximum of 18.06 million km2, 23rd highest, 21st lowest in the 43 years satellite record.

This very average result conceals that this maximum, being on the 30th August, was 10 days earlier than the earliest date of the last 10 years, and 3 weeks earlier than the average of the last 10 years.

Since the 30th August, Antarctic sea ice extent has declined by 388k km2, compared with the 10 year average gain of 307k in that period of 30 Aug to 20 Sept. 
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Click on image  for full-size
To see the maxima table properly, also click maximise

[gerontocrat]

JAXA ANTARCTIC SEA ICE EXTENT:  18,339,507 KM2 as at 21-Sep-2021

- Extent gain on this day 11k, 7 k more than the average gain on this day (of the last 10 years) of 4k,

- Extent is 13th lowest, 31st highest, in the 43 year satellite record of which 5 lower values are in the years before 2000

- Extent is  124 k MORE than 2015
- Extent is  628 k MORE than 2017
- Extent is  860 k LESS than 2006
- Extent is  354 k LESS than 2020
- Extent is  222 k LESS than the 1980's Average
- Extent is  283 k LESS than the 2010's Average

Projections. (Table JAXA-Ant1)

Average remaining melt (of the last 10 years) would produce a minimum in Feb 2021 of 2.57 million km2, 0.43 million km2 above the 2017 record low minimum of 2.15 million km2.
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Click on image to enlarge

[gerontocrat]

JAXA ANTARCTIC SEA ICE EXTENT:  18,361,495 KM2 as at 22-Sep-2021

- Extent gain on this day 22k, 12 k more than the average gain on this day (of the last 10 years) of 10k,
- Extent loss from maximum on this date is 0.36 million km2, 0.16 million km2, (81%) more than the 10 year average of 0.20 million km2.
- Extent is 13th lowest, 31th highest, in the 43 year satellite record of which 5 lower values are in the years before 2000

- Extent is  178 k MORE than 2015
- Extent is  647 k MORE than 2017
- Extent is  834 k LESS than 2006
- Extent is  353 k LESS than 2020
- Extent is  176 k LESS than the 1980's Average
- Extent is  278 k LESS than the 2010's Average

- On average 1.2% of ice loss  from maximum to minimum done, and 152 days to minimum

Projections. (Table JAXA-Ant1)

Average remaining melt (of the last 10 years) would produce a minimum in Feb 2021 of 2.58 million km2, 0.43 million km2 above the 2017 record low minimum of 2.15 million km2.
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Click on image to enlarge

[gerontocrat]

JAXA ANTARCTIC SEA ICE EXTENT:  18,359,756 KM2 as at 23-Sep-2021

- Extent loss on this day 2k, 11 k less than the average loss on this day (of the last 10 years) of 13k,
- Extent loss from maximum on this date is 0.36 million km2, 0.14 million km2, (68%) more than the 10 year average of 0.21 million km2.
- Extent is 14th lowest, 30th highest, in the 43 year satellite record of which 6 lower values are in the years before 2000

- Extent is  216 k MORE than 2015
- Extent is  672 k MORE than 2017
- Extent is  821 k LESS than 2006
- Extent is  430 k LESS than 2020
- Extent is  151 k LESS than the 1980's Average
- Extent is  263 k LESS than the 2010's Average

- On average 1.3% of ice loss  from maximum to minimum done, and 151 days to minimum

Projections. (Table JAXA-Ant1) This table is not yet valid as some years are not past the maximum

Average remaining melt (of the last 10 years) would produce a minimum in Feb 2021 of 2.59 million km2, 0.44 million km2 above the 2017 record low minimum of 2.15 million km2.
_______________________________________________________________
Click on image to enlarge

[gerontocrat]

JAXA ANTARCTIC SEA ICE EXTENT:  18,338,459 KM2 as at 24-Sep-2021

- Extent loss on this day 21k, 7 k less than the average loss on this day (of the last 10 years) of 28k,
- Extent loss from maximum on this date is 0.38 million km2, 0.14 million km2, (57%) more than the 10 year average of 0.24 million km2.
- Extent is 15th lowest, 29th highest, in the 43 year satellite record of which 7 lower values are in the years before 2000

- Extent is  275 k MORE than 2015
- Extent is  730 k MORE than 2017
- Extent is  861 k LESS than 2006
- Extent is  464 k LESS than 2020
- Extent is  149 k LESS than the 1980's Average
- Extent is  257 k LESS than the 2010's Average

- On average 1.5% of ice loss  from maximum to minimum done, and 150 days to minimum

Projections. (Table JAXA-Ant1) This table is not yet valid as some years are not past the maximum

Average remaining melt (of the last 10 years) would produce a minimum in Feb 2021 of 2.60 million km2, 0.45 million km2 above the 2017 record low minimum of 2.15 million km2.
_______________________________________________________________
Click on image to enlarge

[gerontocrat]

JAXA ANTARCTIC SEA ICE EXTENT:  18,301,377 KM2 as at 25-Sep-2021

- Extent loss on this day 37k, 30 k less than the average loss on this day (of the last 10 years) of 7k,
- Extent loss from maximum on this date is 0.42 million km2, 0.17 million km2, (68%) more than the 10 year average of 0.25 million km2.
- Extent is 14th lowest, 30th highest, in the 43 year satellite record of which 6 lower values are in the years before 2000

- Extent is  258 k MORE than 2015
- Extent is  726 k MORE than 2017
- Extent is  890 k LESS than 2006
- Extent is  554 k LESS than 2020
- Extent is  164 k LESS than the 1980's Average
- Extent is  287 k LESS than the 2010's Average

- On average 1.5% of ice loss  from maximum to minimum done, and 149 days to minimum

Projections. (Table JAXA-Ant1) This table is not yet valid as some years are not past the maximum

Average remaining melt (of the last 10 years) would produce a minimum in Feb 2021 of 2.57 million km2, 0.42 million km2 above the 2017 record low minimum of 2.15 million km2.
_______________________________________________________________
Click on image to enlarge

[gerontocrat]

JAXA ANTARCTIC SEA ICE EXTENT:  18,223,347 KM2 as at 26-Sep-2021

- Extent loss on this day 78k, 101 k less than the average gain on this day (of the last 10 years) of 23k,
- Extent loss from maximum on this date is 0.49 million km2, 0.27 million km2, (117%) more than the 10 year average of 0.23 million km2.
- Extent is 11th lowest, 33rd highest, in the 43 year satellite record of which 4 lower values are in the years before 2000

- Extent is  90 k MORE than 2015
- Extent is  589 k MORE than 2017
- Extent is  928 k LESS than 2006
- Extent is  633 k LESS than 2020
- Extent is  223 k LESS than the 1980's Average
- Extent is  385 k LESS than the 2010's Average

- On average 1.4% of ice loss  from maximum to minimum done, and 148 days to minimum

Projections. (Table JAXA-Ant1) This table is not yet valid as some years are not past the maximum

Average remaining melt (of the last 10 years) would produce a minimum in Feb 2021 of 2.47 million km2, 0.32 million km2 above the 2017 record low minimum of 2.15 million km2.
_______________________________________________________________
In the last 30 days, sea ice extent has moved from 38th lowest to 11th lowest in the satellite record
_______________________________________________________________
Click on image to enlarge

[gerontocrat]

JAXA ANTARCTIC SEA ICE EXTENT:  18,119,684 KM2 as at 27-Sep-2021

- Extent loss on this day 104k, 130 k less than the average gain on this day (of the last 10 years) of 26k,
- Extent loss from maximum on this date is 0.60 million km2, 0.39 million km2, (189%) more than the 10 year average of 0.21 million km2.
- Extent is 9th lowest, 35th highest, in the 43 year satellite record of which 3 lower values are in the years before 2000

- Extent is  206 k LESS than 2015
- Extent is  490 k MORE than 2017
- Extent is  963 k LESS than 2006
- Extent is  719 k LESS than 2020
- Extent is  317 k LESS than the 1980's Average
- Extent is  509 k LESS than the 2010's Average

- On average 1.3% of ice loss  from maximum to minimum done, and 147 days to minimum

Projections. (Table JAXA-Ant1)

Average remaining melt (of the last 10 years) would produce a minimum in Feb 2021 of 2.35 million km2, 0.20 million km2 above the 2017 record low minimum of 2.15 million km2.
_______________________________________________________________
On this day extent moved up from 11th lowest to 9th lowest in the satellite record
_______________________________________________________________
Click on image to enlarge

[gerontocrat]

The last month has seen an even more dramatic change in NSIDC Antarctic sea ice area

NSIDC ANTARCTIC SEA ICE AREA:  13,894,768 KM2 as at 27-Sep-2021

- Area loss on this day  72k, 55 k more than the average loss on this day (of the last 10 years) of 17k,
- AREA loss from maximum on this date is 1.26 million km2, 0.96 million km2, (311%) more than the 10 year average of 0.31 million km2.
- AREA is at position #4 in the satellite record of which 1 lower values are in the years before 2000

- AREA is  329 k LESS than 2015
- AREA is  049 k MORE than 2017
- AREA is  1,115 k LESS than 2006
- AREA is  1,379 k LESS than 2020
- AREA is  479 k LESS than the 1980's Average

- On average 2.4% of ice loss  from maximum to minimum done, and 147 days to minimum

Projections. (Table JAXA-Ant1)

Average remaining melt (of the last 10 years) would produce a minimum in Feb 2021 of 1.16 million km2, 0.35 million km2 below the 2017 record low minimum of 2.15 million km2.
_______________________________________________________________
One month ago sea ice area was 42nd lowest, 2nd highest in the 43 year satellite record. On this day it is 4th lowest, 38th highest in that satellite record
_______________________________________________________________
Click on image to enlarge

[Stephan]

What the hell is going on down there? Is a dramatic melting - as observed in 2016 - on its way, without an El Niño present?

[gerontocrat]

What the hell is going on down there? Is a dramatic melting - as observed in 2016 - on its way, without an El Niño present?

I have read papers on why extent shot up in 2014-15, on why extent collapsed  in 2016, on why extent shot up again after 2016, and even a paper talking about multi-decadal oscillations.

But I have never read a paper that gives a coherent convincing story of why maximum and minimum extent and especially 365 day average extent is getting more and more erratic as the years go by.

My guess is that meltwater hosing in very warm years promotes sea ice growth while at the same time warmth is creeping polewards. If both of these are getting more intense over time but with inter-annual variations, then sea ice extent, especially at the maximum could get more erratic.  In other words, the system has become increasingly unstable as it is in permanent transition.

Proof? I wish.....sigh

[I’M IN LOVE WITH A RAGER]

Is there any sort of similarity between the data we have seen regarding Antarctic ice extent and area over the last 10-15 years and the data from the decade or two at the start of the destabilization and terminal decline of the ASI from its old equilibrium? Or was that pre-satellite era/too poorly captured to make a viable comparison? If such a correlation exists, maybe it would lend more support to your hypothesis, gerontocrat

[gerontocrat]

Is there any sort of similarity between the data we have seen regarding Antarctic ice extent and area over the last 10-15 years and the data from the decade or two at the start of the destabilization and terminal decline of the ASI from its old equilibrium? Or was that pre-satellite era/too poorly captured to make a viable comparison? If such a correlation exists, maybe it would lend more support to your hypothesis, gerontocrat

Was the ASI ever really in equilibirium? Mind you, I am too lazy & old to look.

Not enough evidence to call it a hypothesis - only a speculation.

[gerontocrat]

JAXA ANTARCTIC SEA ICE EXTENT:  18,087,539 KM2 as at 28-Sep-2021

- Extent loss on this day 32k, 44 k less than the average gain on this day (of the last 10 years) of 12k,
- Extent loss from maximum on this date is 0.63 million km2, 0.43 million km2, (223%) more than the 10 year average of 0.19 million km2.
- Extent is 9th lowest, 35th highest, in the 43 year satellite record of which 3 lower values are in the years before 2000

- Extent is  421 k LESS than 2015
- Extent is  405 k MORE than 2017
- Extent is  977 k LESS than 2006
- Extent is  719 k LESS than 2020
- Extent is  336 k LESS than the 1980's Average
- Extent is  553 k LESS than the 2010's Average

- On average 1.2% of ice loss  from maximum to minimum done, and 146 days to minimum

Projections. (Table JAXA-Ant1)

Average remaining melt (of the last 10 years) would produce a minimum in Feb 2021 of 2.30 million km2, 0.15 million km2 above the 2017 record low minimum of 2.15 million km2.
_______________________________________________________________
Click on image to enlarge

[gerontocrat]

JAXA ANTARCTIC SEA ICE EXTENT:  18,041,074 KM2 as at 29-Sep-2021

- Extent loss on this day 46k, 42 k more than the average loss on this day (of the last 10 years) of 4k,
- Extent loss from maximum on this date is 0.68 million km2, 0.49 million km2, (258%) more than the 10 year average of 0.19 million km2.
- Extent is 8th lowest, 36th highest, in the 43 year satellite record of which 3 lower values are in the years before 2000

- Extent is  597 k LESS than 2015
- Extent is  335 k MORE than 2017
- Extent is  1,005 k LESS than 2006
- Extent is  707 k LESS than 2020
- Extent is  375 k LESS than the 1980's Average
- Extent is  606 k LESS than the 2010's Average

- On average 1.2% of ice loss  from maximum to minimum done, and 145 days to minimum

Projections. (Table JAXA-Ant1)

Average remaining melt (of the last 10 years) would produce a minimum in Feb 2021 of 2.25 million km2, 0.10 million km2 above the 2017 record low minimum of 2.15 million km2.
_______________________________________________________________
Click on image to enlarge

[gerontocrat]

JAXA ANTARCTIC SEA ICE EXTENT:  18,007,289 KM2 as at 30-Sep-2021

- Extent loss on this day 34k, 30 k more than the average loss on this day (of the last 10 years) of 4k,
- Extent loss from maximum on this date is 0.71 million km2, 0.52 million km2, (280%) more than the 10 year average of 0.19 million km2.
- Extent is 9th lowest, 35th highest, in the 43 year satellite record of which 4 lower values are in the years before 2000

- Extent is  674 k LESS than 2015
- Extent is  274 k MORE than 2017
- Extent is  1,027 k LESS than 2006
- Extent is  711 k LESS than 2020
- Extent is  406 k LESS than the 1980's Average
- Extent is  642 k LESS than the 2010's Average

- On average 1.2% of ice loss  from maximum to minimum done, and 144 days to minimum

Projections. (Table JAXA-Ant1)

Average remaining melt (of the last 10 years) would produce a minimum in Feb 2021 of 2.21 million km2, 0.07 million km2 above the 2017 record low minimum of 2.15 million km2.
_______________________________________________________________
Click on image to enlarge

[gerontocrat]

from JAXA Data - a bit more

The daily sea ice extent maximum maximum occurred at the end of August some 3 weeks earlier than the average, and was followed by relatively high sea ice extent losses. This has reversed the upward trend of 2020 and up to August 21.

The September monthly average sea ice extent graph is attached. The average was 18.4 million km2, 0.12 million km2 below the long-term linear trend and 19th lowest in the 43 year satellite record, compared with 27th lowest in 2020.

I also attach the sea ice extent 365 day trailing average table and graph. 2021 daily extent switched from well above that of 2020 to well below this month, so the 365 day average has begun to fall, at an ever-increasing rate during the month.

On this day, the 365 day average of 11.78 million km2 is still 125k km2 above the long-term linear trend and 1.30 million km2 above the record low minimum on the 5 Oct 2017.

click images to enlarge

[gerontocrat]

NSIDC Antarctic Sea Ice Area (5 day trailing Average)

I attach the same format graphs as in the post above, that tell the same basic story

It's very late (according to my bio-clock) as no figures.

click images to enlarge

[gerontocrat]

JAXA ANTARCTIC SEA ICE EXTENT:  18,017,536 KM2 as at 01-Oct-2021

- Extent gain on this day 10k, 21 k less than the average loss on this day (of the last 10 years) of 11k,
- Extent loss from maximum on this date is 0.70 million km2, 0.50 million km2, (255%) more than the 10 year average of 0.20 million km2.
- Extent is 9th lowest, 35th highest, in the 43 year satellite record of which 4 lower values are in the years before 2000

- Extent is  682 k LESS than 2015
- Extent is  299 k MORE than 2017
- Extent is  982 k LESS than 2006
- Extent is  668 k LESS than 2020
- Extent is  404 k LESS than the 1980's Average
- Extent is  621 k LESS than the 2010's Average

- On average 1.2% of ice loss  from maximum to minimum done, and 143 days to minimum

Projections. (Table JAXA-Ant1)

Average remaining melt (of the last 10 years) would produce a minimum in Feb 2021 of 2.23 million km2, 0.09 million km2 above the 2017 record low minimum of 2.15 million km2.
_______________________________________________________________
Click on image to enlarge

[gerontocrat]

JAXA ANTARCTIC SEA ICE EXTENT:  18,056,348 KM2 as at 02-Oct-2021

- Extent gain on this day 39k, 64 k less than the average loss on this day (of the last 10 years) of 25k,
- Extent loss from maximum on this date is 0.66 million km2, 0.44 million km2, (202%) more than the 10 year average of 0.22 million km2.
- Extent is 9th lowest, 35th highest, in the 43 year satellite record of which 4 lower values are in the years before 2000

- Extent is  655 k LESS than 2015
- Extent is  331 k MORE than 2017
- Extent is  922 k LESS than 2006
- Extent is  635 k LESS than 2020
- Extent is  362 k LESS than the 1980's Average
- Extent is  561 k LESS than the 2010's Average

- On average 1.4% of ice loss  from maximum to minimum done, and 142 days to minimum

Projections. (Table JAXA-Ant1)

Average remaining melt (of the last 10 years) would produce a minimum in Feb 2021 of 2.29 million km2, 0.15 million km2 above the 2017 record low minimum of 2.15 million km2.
_______________________________________________________________
Sea ice extent loss has stalled - a blip, or.....
_______________________________________________________________
Click on image to enlarge

[gerontocrat]

JAXA ANTARCTIC SEA ICE EXTENT:  18,052,369 KM2 as at 03-Oct-2021

- Extent loss on this day 4k, 7 k less than the average loss on this day (of the last 10 years) of 11k,
- Extent loss from maximum on this date is 0.66 million km2, 0.44 million km2, (192%) more than the 10 year average of 0.23 million km2.
- Extent is 10th lowest, 34th highest, in the 43 year satellite record of which 4 lower values are in the years before 2000

- Extent is  658 k LESS than 2015
- Extent is  283 k MORE than 2017
- Extent is  946 k LESS than 2006
- Extent is  667 k LESS than 2020
- Extent is  353 k LESS than the 1980's Average
- Extent is  556 k LESS than the 2010's Average

- On average 1.4% of ice loss  from maximum to minimum done, and 141 days to minimum

Projections. (Table JAXA-Ant1)

Average remaining melt (of the last 10 years) would produce a minimum in Feb 2021 of 2.30 million km2, 0.15 million km2 above the 2017 record low minimum of 2.15 million km2.
_______________________________________________________________
Click on image to enlarge

[gerontocrat]

JAXA ANTARCTIC SEA ICE EXTENT:  18,046,377 KM2 as at 04-Oct-2021

- Extent loss on this day 6k, 15 k less than the average loss on this day (of the last 10 years) of 21k,
- Extent loss from maximum on this date is 0.67 million km2, 0.43 million km2, (177%) more than the 10 year average of 0.24 million km2.
- Extent is 9th lowest, 35th highest, in the 43 year satellite record of which 3 lower values are in the years before 2000

- Extent is  634 k LESS than 2015
- Extent is  222 k MORE than 2017
- Extent is  1,012 k LESS than 2006
- Extent is  644 k LESS than 2020
- Extent is  340 k LESS than the 1980's Average
- Extent is  547 k LESS than the 2010's Average

- On average 1.5% of ice loss  from maximum to minimum done, and 140 days to minimum

Projections. (Table JAXA-Ant1)

Average remaining melt (of the last 10 years) would produce a minimum in Feb 2021 of 2.31 million km2, 0.16 million km2 above the 2017 record low minimum of 2.15 million km2.
_______________________________________________________________
Sea ice extent continues to dither
_______________________________________________________________
Click on image to enlarge

[gerontocrat]

JAXA ANTARCTIC SEA ICE EXTENT:  18,009,382 KM2 as at 05-Oct-2021

- Extent loss on this day 37k, 40 k more than the average gain on this day (of the last 10 years) of 3k,
- Extent loss from maximum on this date is 0.71 million km2, 0.47 million km2, (200%) more than the 10 year average of 0.24 million km2.
- Extent is 9th lowest, 35th highest, in the 43 year satellite record of which 3 lower values are in the years before 2000

- Extent is  652 k LESS than 2015
- Extent is  063 k MORE than 2017
- Extent is  1,066 k LESS than 2006
- Extent is  644 k LESS than 2020
- Extent is  344 k LESS than the 1980's Average
- Extent is  590 k LESS than the 2010's Average

- On average 1.5% of ice loss  from maximum to minimum done, and 139 days to minimum

Projections. (Table JAXA-Ant1)

Average remaining melt (of the last 10 years) would produce a minimum in Feb 2021 of 2.27 million km2, 0.12 million km2 above the 2017 record low minimum of 2.15 million km2.
_______________________________________________________________
Click on image to enlarge

[gerontocrat]

JAXA ANTARCTIC SEA ICE EXTENT:  17,907,014 KM2 as at 06-Oct-2021

- Extent loss on this day 102k, 98 k more than the average loss on this day (of the last 10 years) of 4k,
- Extent loss from maximum on this date is 0.81 million km2, 0.57 million km2, (239%) more than the 10 year average of 0.24 million km2.
- Extent is 3rd lowest, 41th highest, in the 43 year satellite record of which 1 lower values are in the years before 2000 (1986)

- Extent is  761 k LESS than 2015
- Extent is  058 k LESS than 2017
- Extent is  1,119 k LESS than 2006
- Extent is  739 k LESS than 2020
- Extent is  409 k LESS than the 1980's Average
- Extent is  689 k LESS than the 2010's Average

- On average 1.5% of ice loss  from maximum to minimum done, and 138 days to minimum

Projections. (Table JAXA-Ant1)

Average remaining melt (of the last 10 years) would produce a minimum in Feb 2021 of 2.17 million km2, 0.02 million km2 above the 2017 record low minimum of 2.15 million km2.
_______________________________________________________________
A century sea ice extent loss on this day send total extent from 9th lowest to 3rd lowest in the 43 year satellite record. This event started at the end of August with extent 38th lowest.
_______________________________________________________________
Click on image to enlarge

[gerontocrat]

JAXA ANTARCTIC SEA ICE EXTENT:  17,841,063 KM2 as at 07-Oct-2021

- Extent loss on this day 66k, 37 k more than the average loss on this day (of the last 10 years) of 29k,
- Extent loss from maximum on this date is 0.88 million km2, 0.61 million km2, (229%) more than the 10 year average of 0.27 million km2.
- Extent is 3th lowest, 41th highest, in the 43 year satellite record of which 1 lower values are in the years before 2000

- Extent is  823 k LESS than 2015
- Extent is  150 k LESS than 2017
- Extent is  1,152 k LESS than 2006
- Extent is  786 k LESS than 2020
- Extent is  441 k LESS than the 1980's Average
- Extent is  728 k LESS than the 2010's Average

- On average 1.7% of ice loss  from maximum to minimum done, and 137 days to minimum

Projections. (Table JAXA-Ant1)

Average remaining melt (of the last 10 years) would produce a minimum in Feb 2022 of 2.13 million km2, 0.02 million km2 below the 2017 record low minimum of 2.15 million km2.
_______________________________________________________________
Click on image to enlarge

[kassy]

a minimum in Feb 2021

Bit more to automate or fix.

[gerontocrat]

JAXA ANTARCTIC SEA ICE EXTENT:  17,839,577 KM2 as at 08-Oct-2021

- Extent loss on this day 1k, 34 k less than the average loss on this day (of the last 10 years) of 35k,
- Extent loss from maximum on this date is 0.88 million km2, 0.58 million km2, (192%) more than the 10 year average of 0.30 million km2.
- Extent is 6th lowest, 38th highest, in the 43 year satellite record of which 3 lower values are in the years before 2000

- Extent is  815 k LESS than 2015
- Extent is  155 k LESS than 2017
- Extent is  1,127 k LESS than 2006
- Extent is  762 k LESS than 2020
- Extent is  422 k LESS than the 1980's Average
- Extent is  695 k LESS than the 2010's Average

- On average 1.9% of ice loss  from maximum to minimum done, and 136 days to minimum

Projections. (Table JAXA-Ant1)

Average remaining melt (of the last 10 years) would produce a minimum in Feb 2022  of 2.16 million km2, 0.01 million km2 above the 2017 record low minimum of 2.15 million km2.
_______________________________________________________________
Click on image to enlarge

[Altai]

The second figure shows an increase in extent. Is anything wrong?

[gerontocrat]

The second figure shows an increase in extent. Is anything wrong?

Mea Culpa

Well spotted

For some unknown reason the graph picked up the data for 6 October. A gremlin for 8 October only. I must have been too slick with amending the spreadsheet at some time or other.

Ho hum.

[gerontocrat]

NSIDC ANTARCTIC SEA ICE AREA  (5 day trailing average):  13,454,120 KM2 as at 08-Oct-2021

- Area loss on this day  41k, 20 k more than the average loss on this day (of the last 10 years) of 21k,
- AREA loss from maximum on this date is 1.70 million km2, 1.25 million km2, (275%) more than the 10 year average of 0.45 million km2.
- AREA is 1st lowest in the satellite record

- AREA is  1,111 k LESS than 2015
- AREA is  192 k LESS than 2017
- AREA is  1,712 k LESS than 2006
- AREA is  1,471 k LESS than 2020
- AREA is  812 k LESS than the 1980's Average

- On average 3.5% of ice loss  from maximum to minimum done, and 136 days to minimum

Projections. (Table JAXA-Ant1)

Average remaining melt (of the last 10 years) would produce a minimum in Feb 2021 of 0.76 million km2, 0.75 million km2 below the 2017 record low minimum of 2.15 million km2.
_______________________________________________________________
The projection above should be taken as an additional indicator of the oddness of this years melt season to date (rather than as an expectation of the minimum), to which can be added that Antarctic sea ice area has been lowest in the satellite record for the last 3 days after being at 2nd highest at the end of August.

_______________________________________________________________
Click on image to enlarge

[gerontocrat]

JAXA ANTARCTIC SEA ICE EXTENT:  17,832,851 KM2 as at 09-Oct-2021

- Extent loss on this day 7k, 20 k less than the average loss on this day (of the last 10 years) of 27k,
- Extent loss from maximum on this date is 0.88 million km2, 0.56 million km2, (173%) more than the 10 year average of 0.32 million km2.
- Extent is 6th lowest, 38th highest, in the 43 year satellite record of which 3 lower values are in the years before 2000

- Extent is  790 k LESS than 2015
- Extent is  161 k LESS than 2017
- Extent is  1,117 k LESS than 2006
- Extent is  741 k LESS than 2020
- Extent is  424 k LESS than the 1980's Average
- Extent is  679 k LESS than the 2010's Average

- On average 2.0% of ice loss  from maximum to minimum done, and 135 days to minimum

Projections. (Table JAXA-Ant1)

Average remaining melt (of the last 10 years) would produce a minimum in Feb 2022  of 2.18 million km2, 0.03 million km2 above the 2017 record low minimum of 2.15 million km2.
_______________________________________________________________
Click on image to enlarge

[gerontocrat]

JAXA ANTARCTIC SEA ICE EXTENT:  17,813,436 KM2 as at 10-Oct-2021

- Extent loss on this day 19k, 9 k less than the average loss on this day (of the last 10 years) of 28k,
- Extent loss from maximum on this date is 0.90 million km2, 0.56 million km2, (160%) more than the 10 year average of 0.35 million km2.
- Extent is 6th lowest, 38th highest, in the 43 year satellite record of which 3 lower values are in the years before 2000

- Extent is  721 k LESS than 2015
- Extent is  183 k LESS than 2017
- Extent is  1,077 k LESS than 2006
- Extent is  697 k LESS than 2020
- Extent is  428 k LESS than the 1980's Average
- Extent is  675 k LESS than the 2010's Average

- On average 2.2% of ice loss  from maximum to minimum done, and 134 days to minimum

Projections. (Table JAXA-Ant1)

Average remaining melt (of the last 10 years) would produce a minimum in Feb 2022  of 2.18 million km2, 0.03 million km2 above the 2017 record low minimum of 2.15 million km2.
_______________________________________________________________
Click on image to enlarge

[gerontocrat]

JAXA ANTARCTIC SEA ICE EXTENT:  17,769,048 KM2 as at 11-Oct-2021

- Extent loss on this day 44k, 1 k more than the average loss on this day (of the last 10 years) of 43k,
- Extent loss from maximum on this date is 0.95 million km2, 0.56 million km2, (147%) more than the 10 year average of 0.38 million km2.
- Extent is 4th lowest, 40th highest, in the 43 year satellite record of which 2 lower values are in the years before 2000

- Extent is  699 k LESS than 2015
- Extent is  180 k LESS than 2017
- Extent is  1,026 k LESS than 2006
- Extent is  654 k LESS than 2020
- Extent is  453 k LESS than the 1980's Average
- Extent is  682 k LESS than the 2010's Average

- On average 2.4% of ice loss  from maximum to minimum done, and 133 days to minimum

Projections. (Table JAXA-Ant1)

Average remaining melt (of the last 10 years) would produce a minimum in Feb 2022  of 2.17 million km2, 0.03 million km2 above the 2017 record low minimum of 2.15 million km2.

_______________________________________________________________
Click on image to enlarge