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Paddy

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Re: Sea Ice Extent around Antarctica
« Reply #400 on: February 03, 2017, 10:50:19 AM »
Only about 3 weeks untll the minimum now, based on previous years.

Wipneus

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Re: Sea Ice Extent around Antarctica
« Reply #401 on: February 03, 2017, 02:12:23 PM »
SH NSIDC extent: -46k
SH NSIDC area: -34k

2017 extent minimum is now 5th lowest  (unchanged)
2017 area minimum is now 21st lowest  (was #24)

Extent
1 1997-02-27 2.264152
2 1993-02-19 2.280783
3 2011-02-22 2.318847
4 1984-02-27 2.381731
5 2017-02-02 2.428219
6 2006-02-20 2.486597
Area
1 1993-02-26 1.248163
2 1984-02-27 1.509585
3 1996-02-25 1.535481
4 2000-02-18 1.561033
5 2006-03-04 1.565059
6 1999-02-26 1.577058
7 1981-03-03 1.588790
8 1997-02-19 1.589288
9 1985-02-19 1.635733
10 1992-02-23 1.641926
11 1980-02-27 1.646186
12 2002-02-20 1.649281
13 1998-02-26 1.650298
14 2011-02-26 1.677629
15 1988-02-24 1.691611
16 1982-02-17 1.713860
17 2016-02-17 1.729589
18 1983-02-25 1.738279
19 1986-02-27 1.763319
20 1987-02-24 1.781372
21 2017-02-02 1.781591
22 2009-02-22 1.794061
23 1991-02-25 1.797485
24 2005-02-25 1.798750


In daily values 2017 extent is lowest, and area second lowest.

Buddy

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Re: Sea Ice Extent around Antarctica
« Reply #402 on: February 03, 2017, 02:19:00 PM »
Quote
Extent
1 1997-02-27 2.264152
2 1993-02-19 2.280783
3 2011-02-22 2.318847
4 1984-02-27 2.381731
5 2017-02-02 2.428219
6 2006-02-20 2.486597
Area
1 1993-02-26 1.248163
2 1984-02-27 1.509585
3 1996-02-25 1.535481

That 1993 Area sure looks like a "tough nut to crack". 
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Lord M Vader

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Re: Sea Ice Extent around Antarctica
« Reply #403 on: February 03, 2017, 10:32:50 PM »
With about 2 weeks until minimum I have identified five minor areas which will be be crucial for the final outcome. See attached figure. Courtesy: University of Bremen.

While the sea ice in the Ross Sea is exceptionally low and Weddell Sea very low it's fascinating to see the sea ice extent in East Antarctica run about normal or even somewhat above normal. To me, it seems like the remaining sea ice in East Antarctica is more or less completely void of melting momentum. The ice in Somov Sea have been very resilient so far and I wonder if it's going to melt any more significantly until refreezing starts.

Finally, the 5-day forecast from CCI_Reanalyzer indicates very warm days ahead for West Antarctica while cooler than normal conditions is foreseen for East Antarctica. See attached figure. Courtesy: CCI_Reanalyzer

Neven

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Re: Sea Ice Extent around Antarctica
« Reply #404 on: February 03, 2017, 11:15:19 PM »
Maybe a stupid question, but why doesn't the sea ice in the Weddell Sea melt out more? Is it because it is more or less enclosed, unlike the rest of the sea ice around Antarctica?
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Tigertown

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Re: Sea Ice Extent around Antarctica
« Reply #405 on: February 03, 2017, 11:28:04 PM »
Maybe a stupid question, but why doesn't the sea ice in the Weddell Sea melt out more? Is it because it is more or less enclosed, unlike the rest of the sea ice around Antarctica?
I'm thinking the Peninsula blocks both water currents and because of elevation, at the very least alters wind patterns. Just a guess.

oren

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Re: Sea Ice Extent around Antarctica
« Reply #406 on: February 03, 2017, 11:36:06 PM »
Maybe a stupid question, but why doesn't the sea ice in the Weddell Sea melt out more? Is it because it is more or less enclosed, unlike the rest of the sea ice around Antarctica?
I'm thinking the Peninsula blocks both water currents and because of elevation, at the very least alters wind patterns. Just a guess.
My layman understanding is the same, plus the wind pattern around Antarctica is clockwise, hence the east side of the peninsula is protected.

magnamentis

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Re: Sea Ice Extent around Antarctica
« Reply #407 on: February 04, 2017, 12:12:49 AM »
Maybe a stupid question, but why doesn't the sea ice in the Weddell Sea melt out more? Is it because it is more or less enclosed, unlike the rest of the sea ice around Antarctica?
I'm thinking the Peninsula blocks both water currents and because of elevation, at the very least alters wind patterns. Just a guess.
My layman understanding is the same, plus the wind pattern around Antarctica is clockwise, hence the east side of the peninsula is protected.

my 2 cents are that the wind over the peninsula turns into some kind of foehn winds that would make them even slightly warmer ( but not really warm of course )

the main reason might be the assult of the heavy seas on the western side which is missing on the eastern (lee) side. Lee not only as far as the winds are concerned but especially the ocean currents with their wave action and the swells.

so i agree that the eastern side is potected, hence in "Lee" but that the ocean has the greater impact on the western side than the winds have. there must be foehn winds if a wind comes over an elevation and drops down to sea-level (or any lower level) on the other side, that's the case every where in the world where wind currents flow over a mountain ridge, whatever the names are (chenook foehn, mistral, tramontana and the likes.
« Last Edit: February 04, 2017, 11:55:48 AM by magnamentis »

Tigertown

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Re: Sea Ice Extent around Antarctica
« Reply #408 on: February 04, 2017, 05:30:42 AM »
For Feb. 3rd JAXA has posted 2,382,580 km2 for SIE around Antarctica.

Neven

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Re: Sea Ice Extent around Antarctica
« Reply #409 on: February 04, 2017, 10:57:22 AM »
Thanks for the answers. I guessed as much. If area was so low at the min in 1993, I guess something would have happened there, right? Given that there is so little ice elsewhere. Maybe some extreme katabatic winds - that MM mentions - coming down from those mountains pushing the ice outwards?
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Lord M Vader

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Re: Sea Ice Extent around Antarctica
« Reply #410 on: February 04, 2017, 01:39:33 PM »
Just a lousy 2K drop today to 2,426 Mn km2.... 5-day average down to 2,463 Mn km2. We are still 4th lowest on record.

Wipneus

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Re: Sea Ice Extent around Antarctica
« Reply #411 on: February 04, 2017, 02:37:18 PM »
SH NSIDC extent: -1.8k
SH NSIDC area: -12.1k

2017 extent minimum is now 5th lowest  (unchanged)
2017 area minimum is now 20st lowest  (was #21)

Extent
1 1997-02-27 2.264152
2 1993-02-19 2.280783
3 2011-02-22 2.318847
4 1984-02-27 2.381731
5 2017-02-03 2.426406
Area
1 1993-02-26 1.248163
2 1984-02-27 1.509585
3 1996-02-25 1.535481
4 2000-02-18 1.561033
5 2006-03-04 1.565059
6 1999-02-26 1.577058
7 1981-03-03 1.588790
8 1997-02-19 1.589288
9 1985-02-19 1.635733
10 1992-02-23 1.641926
11 1980-02-27 1.646186
12 2002-02-20 1.649281
13 1998-02-26 1.650298
14 2011-02-26 1.677629
15 1988-02-24 1.691611
16 1982-02-17 1.713860
17 2016-02-17 1.729589
18 1983-02-25 1.738279
19 1986-02-27 1.763319
20 2017-02-03 1.769445
21 1987-02-24 1.781372


In daily values 2017 extent is still lowest, and area still second lowest.

johnm33

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Re: Sea Ice Extent around Antarctica
« Reply #412 on: February 04, 2017, 03:16:58 PM »
Just to add to Nevens ans. This image shows the amphidromic points around which the tides rotate, clockwise in the SH, so rotating into and within the Weddel sea. There's limited movement at those foci, so I'm guessing any water entering is going to use up it's melting potential on the eastern side, generating fresher water so as it moves out on the western side it's easier to refreeze. Plus you have the stability of the point within the sea inhibiting breakup.

From http://www.esr.org/documents/padman/robertson_etal_98/robertson_etal_98.pdf where there are more images including bathymetry.

Tigertown

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Re: Sea Ice Extent around Antarctica
« Reply #413 on: February 05, 2017, 10:22:52 AM »
For Feb. 4th JAXA has posted 2,373,021 km2 for SIE around Antarctica.

Down by 9,559 km2.

Lord M Vader

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Re: Sea Ice Extent around Antarctica
« Reply #414 on: February 05, 2017, 01:59:17 PM »
And for Feb. 4, NSIDC is reporting another lousy 8K drop to 2,418 Mn km2. At least another 10 days are ahead until we reach the date when the earliest minimum occurred (Feb. 15). And time is starting to run out now to make a new record low minimum to occur. The last 6 days have seen a drop of "only" 94K according to NSIDC data.

Wipneus

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Re: Sea Ice Extent around Antarctica
« Reply #415 on: February 05, 2017, 02:24:07 PM »
The remaining ice holds bravely:

SH NSIDC extent: -8.0k
SH NSIDC area: -10.5k

Still it means the drop in area means one place lost in the annual minimum ranking. Area is now #19, while extent stays at #5.
Extent
1 1997-02-27 2.264152
2 1993-02-19 2.280783
3 2011-02-22 2.318847
4 1984-02-27 2.381731
5 2017-02-04 2.418404
Area
1 1993-02-26 1.248163
2 1984-02-27 1.509585
3 1996-02-25 1.535481
4 2000-02-18 1.561033
5 2006-03-04 1.565059
6 1999-02-26 1.577058
7 1981-03-03 1.588790
8 1997-02-19 1.589288
9 1985-02-19 1.635733
10 1992-02-23 1.641926
11 1980-02-27 1.646186
12 2002-02-20 1.649281
13 1998-02-26 1.650298
14 2011-02-26 1.677629
15 1988-02-24 1.691611
16 1982-02-17 1.713860
17 2016-02-17 1.729589
18 1983-02-25 1.738279
19 2017-02-04 1.758907
20 1986-02-27 1.763319


In daily values 2017 extent is still lowest, and area still second lowest:
extent SH
2007-02-04 3.101119
1988-02-04 3.080869
1985-02-04 3.036704
2016-02-04 2.963989
1984-02-04 2.962201
1997-02-04 2.825638
2006-02-04 2.784496
2011-02-04 2.769953
1993-02-04 2.761674
2017-02-04 2.418404
area SH
1999-02-04 2.001531
1982-02-04 1.992335
1984-02-04 1.983035
2016-02-04 1.980406
1981-02-04 1.962684
1997-02-04 1.910146
2006-02-04 1.889583
2000-02-04 1.828389
2017-02-04 1.758907
1993-02-04 1.556669



oren

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Re: Sea Ice Extent around Antarctica
« Reply #416 on: February 05, 2017, 03:54:55 PM »
And for Feb. 4, NSIDC is reporting another lousy 8K drop to 2,418 Mn km2. At least another 10 days are ahead until we reach the date when the earliest minimum occurred (Feb. 15). And time is starting to run out now to make a new record low minimum to occur. The last 6 days have seen a drop of "only" 94K according to NSIDC data.
Ever since I published my statistical prediction it's been stalling  ::)

Paddy

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Re: Sea Ice Extent around Antarctica
« Reply #417 on: February 05, 2017, 06:04:36 PM »
Just as when I was saying "it's about to start slowing down" the next few days after that saw good large drops. Easy to trip up on predictions.
« Last Edit: February 06, 2017, 10:32:54 AM by Paddy »

Tigertown

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Re: Sea Ice Extent around Antarctica
« Reply #418 on: February 06, 2017, 05:46:34 AM »
For Feb. 5th JAXA has posted 2,356,536 km2 for SIE around Antarctica.

Down by 16,485 km2.


Wipneus

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Re: Sea Ice Extent around Antarctica
« Reply #419 on: February 06, 2017, 02:06:04 PM »
NSIDC area makes a recovery! (0.3k or half a pixel worth of sea ice).

SH NSIDC extent: -20.0k
SH NSIDC area: +0.3k

Neither extent or area makes any change in the rankings today, so same as yesterday.

iceman

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Re: Sea Ice Extent around Antarctica
« Reply #420 on: February 06, 2017, 04:44:49 PM »
With about 2 weeks until minimum I have identified five minor areas which will be be crucial for the final outcome. See attached figure. Courtesy: University of Bremen.
   ....

With a stationary low off the coast and a deeper low approaching, it looks like #2 and #3 (and eastwards) will be significant contributors to extent loss between now and the minimum.
    courtesy: ClimateReanalyzer.org

Paddy

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Re: Sea Ice Extent around Antarctica
« Reply #421 on: February 06, 2017, 07:44:47 PM »
I'd agree with the areas 2&3 (Belliingshausen sea) forecast for a drop, especially as there's been a recent rise there that's likely to be dispersal under current conditions.

Tigertown

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Re: Sea Ice Extent around Antarctica
« Reply #422 on: February 07, 2017, 05:55:51 AM »
Jaxa dropped only a little today (5th) and landed at 2,353,285 km2.

Since it has leveled off so, I do not intend to post everyday, short of big changes on a given date or accumulated over several days. If someone else feels inclined to post JAXA SIE, fine. If not, I will do so as called for.

Darvince

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Re: Sea Ice Extent around Antarctica
« Reply #423 on: February 07, 2017, 06:37:10 AM »
Nullschool shows that the losses may accelerate again over the coming days, perhaps peaking around the 10th, as the main driver of Antarctic sea ice change is wind patterns:

https://earth.nullschool.net/#2017/02/10/0600Z/wind/surface/level/orthographic=-265.39,-83.88,762

Wipneus

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Re: Sea Ice Extent around Antarctica
« Reply #424 on: February 07, 2017, 02:02:26 PM »
SH NSIDC extent: -12.9k
SH NSIDC area: -31.8k

2017 extent minumum stays at place 5 (but is now only less than 4 k from #4)
Area skips 2 and is now at place 17.

Extent
1 1997-02-27 2.264152
2 1993-02-19 2.280783
3 2011-02-22 2.318847
4 1984-02-27 2.381731
5 2017-02-06 2.385412

Area
1 1993-02-26 1.248163
2 1984-02-27 1.509585
3 1996-02-25 1.535481
4 2000-02-18 1.561033
5 2006-03-04 1.565059
6 1999-02-26 1.577058
7 1981-03-03 1.588790
8 1997-02-19 1.589288
9 1985-02-19 1.635733
10 1992-02-23 1.641926
11 1980-02-27 1.646186
12 2002-02-20 1.649281
13 1998-02-26 1.650298
14 2011-02-26 1.677629
15 1988-02-24 1.691611
16 1982-02-17 1.713860
17 2017-02-06 1.727467
18 2016-02-17 1.729589
19 1983-02-25 1.738279




DrTskoul

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Re: Sea Ice Extent around Antarctica
« Reply #425 on: February 07, 2017, 02:04:08 PM »
A horse race to the finish line....

Pavel

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Re: Sea Ice Extent around Antarctica
« Reply #426 on: February 07, 2017, 09:11:34 PM »
The melting momentum is strong in the Weddel sea. Wind pushes ice pack outward of the coast and polynya opens along the penisula

iamlsd

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Re: Sea Ice Extent around Antarctica
« Reply #427 on: February 08, 2017, 01:09:15 PM »
Thought I'd have a shot at this:

Jaxa Sea Ice Extent for 7/02/2017 is up a little at 2,355,011 km2.

Hope I'm sourcing this correctly from https://ads.nipr.ac.jp/vishop/#/extent

Lord M Vader

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Re: Sea Ice Extent around Antarctica
« Reply #428 on: February 08, 2017, 01:41:45 PM »
Oooops! An decent uptick of 43K today to 2,428 Mn km2! And the 5-day average is the same as yesterday, 2,411 Mn km2. And only about a week left before refreezing will be very imminent. Will we end up with a surprising no new record low extent for 2017? What an anticlimax that would be! We are currently ONLY 164K above the 1997 record low minimum!

Tigertown

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Re: Sea Ice Extent around Antarctica
« Reply #429 on: February 08, 2017, 01:50:15 PM »
Oooops! An decent uptick of 43K today to 2,428 Mn km2! And the 5-day average is the same as yesterday, 2,411 Mn km2. And only about a week left before refreezing will be very imminent. Will we end up with a surprising no new record low extent for 2017? What an anticlimax that would be! We are currently ONLY 164K above the 1997 record low minimum!

It is kind of like all the excess energy has shifted to the Arctic again. At least, at the surface.

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Re: Sea Ice Extent around Antarctica
« Reply #430 on: February 08, 2017, 02:18:46 PM »
SH NSIDC extent: +42.4k
SH NSIDC area: +7.6k

Annual minimums did not change obviously.
In the daily rankings 2017 area lost one place and is now #3 after 1993 and 2000:

area SH
2016-02-07 1.943511
1996-02-07 1.918787
1985-02-07 1.895955
1999-02-07 1.870074
1981-02-07 1.816876
2006-02-07 1.813437
1997-02-07 1.804732
2017-02-07 1.735088
2000-02-07 1.712887
1993-02-07 1.469682

Pavel

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Re: Sea Ice Extent around Antarctica
« Reply #431 on: February 08, 2017, 03:30:07 PM »
Ice pack is spreading in the Weddell sea, this pattern will continue in several days. Well, really +-100k of extent is not big deal. The more important is how high will be SSTs and what will happen thereby in the freezing season

iceman

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Re: Sea Ice Extent around Antarctica
« Reply #432 on: February 08, 2017, 03:34:39 PM »
Has anyone seen graphs or calculations for insolation this Antarctic summer?  Beyond the absolute extent anomaly, the missing ice is mostly at higher latitudes, and locations where ice exceeds the median edge are relatively lower-latitude.  This would have a modest multiplier effect on insolation anomaly, assuming near-normal cloud conditions around the solstice.

Antarctic sea ice extent February 5, 2017
Credit: National Snow and Ice Data Center

Tigertown

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Re: Sea Ice Extent around Antarctica
« Reply #433 on: February 09, 2017, 05:25:43 AM »
For Feb. 8th JAXA has posted 2,321,526 km2 for SIE around Antarctica.

Lord M Vader

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Re: Sea Ice Extent around Antarctica
« Reply #434 on: February 09, 2017, 07:39:23 AM »
From Bremens pic today, it seems like refreezing has begun at East Antarctica. The end is coming closer and I won't be surprised if we are going to see a record early minimum date this year.

Paddy

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Re: Sea Ice Extent around Antarctica
« Reply #435 on: February 09, 2017, 08:47:10 AM »
I'd still predict there may be a little more melting to come this next week, in Belliinghausen anyway, based on the forecast temperatures and fragility of what's there.

5 day temperature anomaly forecast from climatereanalyzer.org:



(And the high winds forecast for the same sea from the same source)
« Last Edit: February 10, 2017, 11:05:25 AM by Paddy »

Wipneus

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Re: Sea Ice Extent around Antarctica
« Reply #436 on: February 09, 2017, 02:31:57 PM »
SH NSIDC extent: -14.2k
SH NSIDC area: -18.5k

No changes in the annual minimum rankings.

In the daily rankings extent is #1 lowest, area is at #2 (skipped 2000 again).

crandles

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Re: Sea Ice Extent around Antarctica
« Reply #437 on: February 09, 2017, 03:17:26 PM »
4960,1997,02,19,577584000,2251372

10038,2011,02,22,1019606400,2315254

12212,2017,02,08,1207785600,2321526

ADS/JAXA/IJIS
statistical tie for 2nd lowest year (probably even for lowest?)

70k above record lowest and fall of 34k in last day.   ... so ~3 days to record low..... or 35k in previous 5 days so perhaps ~10 days to record low... or maybe minimum is past before record is reached....


steve s

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Re: Sea Ice Extent around Antarctica
« Reply #438 on: February 09, 2017, 07:37:42 PM »
Whether a new low or not, the number of square kilometers of multi-year sea ice has been drastically reduced; the remaining multi-year sea ice possibly drastically thinned; the surface waters warmed in preparation for the next freeze. Next year will probably be another low year.

The refreeze will start further south on average than most other years, so it might start early, although the warm waters probably mean at a slower than usual rate of progress.

oren

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Re: Sea Ice Extent around Antarctica
« Reply #439 on: February 09, 2017, 11:20:57 PM »
So I've done some number crunching using NSIDC data for Jan 26 as current date. 1997 vs 2017.
Looking at each region separately:
bham: now 504k, was 462k on 1997 same date. Fell to 182k at 1997 minimum, declining 280k
wedd: now 1149k, was 1299k on 1997 same date. Fell to 1184k at 1997 minimum, declining 115k
indo: now 277k, was 287k on 1997 same date. Fell to 124k at 1997 minimum, declining 163k
wpac: now 641k, was 569k on 1997 same date. Fell to 426k at 1997 minimum, declining 144k
ross: now 132k, was 661k on 1997 same date. Fell to 348k at 1997 minimum, declining 313k

Using the following guesswork:
bham declines 280k to minimum, same as 1997 though it currently has more ice
wedd declines 120k to minimum, or 220k *
indo declines 163k to minimum, same as 1997
wpac declines 144k to minimum, same as 1997 though it currently has more ice
ross declines 30k to minimum, or 100k **
*** The above can be improved for wedd and ross by checking each year's decline to its own minimum date, instead of using Feb 27 for all. The above can be improved for all regions by looking at other similar years and averaging their declines to minimum instead of just using 1997.

The bottom line gives us the following NSIDC SIE minimum based on regional extrapolation:
Low decline scenario - 737k, down to 1,965k
High decline scenario – 907k, down to 1,795k
Midpoint decline – 822k, down to 1,880k

Following this statistical guesswork, I think <2m has a much higher probability than >2m.
So I've decided to revisit my analysis and find out where it failed.
From Jan 26 to Feb 8:
bham: fell 58k, while 1997 fell by 157k. Average loss for this period is ~120k.
wedd: fell 77k, while 1997 fell by 157k. Average loss for this period is ~140k
indo: fell 75k, while 1997 fell by 104k. Average loss for this period is ~84k.
wpac: fell 24k, while 1997 fell by 107k. Average loss for this period is ~68k.
ross: fell 56k, as expected considering its starting point.
All areas fall within historical variance but on the low side, while 1997 consistently took the high side.
Bottom line, I've made serious statistical errors, using an above average year as a guide, and disregarding the very high variability in antarctic numbers (being used to the arctic). In addition, 2017 somehow produced below-average numbers in all areas for this period, so the prediction was doomed anyway...

georged

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Re: Sea Ice Extent around Antarctica
« Reply #440 on: February 10, 2017, 05:19:17 AM »
So I've done some number crunching using NSIDC data for Jan 26 as current date. 1997 vs 2017.
Looking at each region separately:
bham: now 504k, was 462k on 1997 same date. Fell to 182k at 1997 minimum, declining 280k
wedd: now 1149k, was 1299k on 1997 same date. Fell to 1184k at 1997 minimum, declining 115k
indo: now 277k, was 287k on 1997 same date. Fell to 124k at 1997 minimum, declining 163k
wpac: now 641k, was 569k on 1997 same date. Fell to 426k at 1997 minimum, declining 144k
ross: now 132k, was 661k on 1997 same date. Fell to 348k at 1997 minimum, declining 313k

Using the following guesswork:
bham declines 280k to minimum, same as 1997 though it currently has more ice
wedd declines 120k to minimum, or 220k *
indo declines 163k to minimum, same as 1997
wpac declines 144k to minimum, same as 1997 though it currently has more ice
ross declines 30k to minimum, or 100k **
*** The above can be improved for wedd and ross by checking each year's decline to its own minimum date, instead of using Feb 27 for all. The above can be improved for all regions by looking at other similar years and averaging their declines to minimum instead of just using 1997.

The bottom line gives us the following NSIDC SIE minimum based on regional extrapolation:
Low decline scenario - 737k, down to 1,965k
High decline scenario – 907k, down to 1,795k
Midpoint decline – 822k, down to 1,880k

Following this statistical guesswork, I think <2m has a much higher probability than >2m.
So I've decided to revisit my analysis and find out where it failed.
From Jan 26 to Feb 8:
bham: fell 58k, while 1997 fell by 157k. Average loss for this period is ~120k.
wedd: fell 77k, while 1997 fell by 157k. Average loss for this period is ~140k
indo: fell 75k, while 1997 fell by 104k. Average loss for this period is ~84k.
wpac: fell 24k, while 1997 fell by 107k. Average loss for this period is ~68k.
ross: fell 56k, as expected considering its starting point.
All areas fall within historical variance but on the low side, while 1997 consistently took the high side.
Bottom line, I've made serious statistical errors, using an above average year as a guide, and disregarding the very high variability in antarctic numbers (being used to the arctic). In addition, 2017 somehow produced below-average numbers in all areas for this period, so the prediction was doomed anyway...

'Predicting is hard, especially about the future.'

Tigertown

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Re: Sea Ice Extent around Antarctica
« Reply #441 on: February 10, 2017, 05:28:40 AM »
Hold the press!
New number posted by JAXA for SIE around Antarctica is 2,279,405 km2....

Pavel

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Re: Sea Ice Extent around Antarctica
« Reply #442 on: February 10, 2017, 07:37:22 AM »
NSIDC's grid is bigger and it shows polynyas as 100% SIE. Since ice packs drift toward the coast both in East and West,NSIDC's extent may significantly drop

Wipneus

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Re: Sea Ice Extent around Antarctica
« Reply #443 on: February 10, 2017, 03:11:14 PM »
SH NSIDC extent: -51.6k
SH NSIDC area: -53.8k

In the annual minimum rankings, one place advanced in extent and three in area:

Extent
1 1997-02-27 2.264152
2 1993-02-19 2.280783
3 2011-02-22 2.318847
4 2017-02-09 2.362004
5 1984-02-27 2.381731

Area
1 1993-02-26 1.248163
2 1984-02-27 1.509585
3 1996-02-25 1.535481
4 2000-02-18 1.561033
5 2006-03-04 1.565059
6 1999-02-26 1.577058
7 1981-03-03 1.588790
8 1997-02-19 1.589288
9 1985-02-19 1.635733
10 1992-02-23 1.641926
11 1980-02-27 1.646186
12 2002-02-20 1.649281
13 1998-02-26 1.650298
14 2017-02-09 1.662847
15 2011-02-26 1.677629
16 1988-02-24 1.691611
17 1982-02-17 1.713860


No changes in the daily rankings.

iceman

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Re: Sea Ice Extent around Antarctica
« Reply #444 on: February 10, 2017, 03:20:18 PM »
   ....
The refreeze will start further south on average than most other years, so it might start early, although the warm waters probably mean at a slower than usual rate of progress.

I'll guess an extent minimum on the 17th, following an uptick around the 13th and a couple days' decline under these conditions:

Tigertown

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Re: Sea Ice Extent around Antarctica
« Reply #445 on: February 11, 2017, 05:32:27 AM »
For Feb. 10th JAXA has posted 2,255,361 km2 for SIE around Antarctica.

magnamentis

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Re: Sea Ice Extent around Antarctica
« Reply #446 on: February 11, 2017, 11:34:34 AM »
For Feb. 10th JAXA has posted 2,255,361 km2 for SIE around Antarctica.

http://forum.arctic-sea-ice.net/index.php/topic,230.msg102758.html#msg102758

worth to cross-link, espen obviously thought it's worth a mention in his arctic thread :-)

Lord M Vader

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Re: Sea Ice Extent around Antarctica
« Reply #447 on: February 11, 2017, 02:22:44 PM »
Big drop down to 2,309 Mn km2. We are, from Wipneus numbers, now on third place behind 1997 and 1993. "Only" about 45K to get an al time low daily minimum (NSIDC numbers).

Wipneus

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Re: Sea Ice Extent around Antarctica
« Reply #448 on: February 11, 2017, 03:04:52 PM »
Indeed, drops everywhere except Ross Sea and Weddel Sea regions. The numbers are:

SH "NSIDC extent": -53.1k
SH "NSIDC area": -56.5k

In the minimum rankings, 2017 extent is now in third place (from four) . A similar drop will be enough to set a record all time (satellite era) low.
"NSIDC area" is now nine ( from 14):


Extent
1 1997-02-27 2.264152
2 1993-02-19 2.280783
3 2017-02-10 2.308883
4 2011-02-22 2.318847

Area
1 1993-02-26 1.248163
2 1984-02-27 1.509585
3 1996-02-25 1.535481
4 2000-02-18 1.561033
5 2006-03-04 1.565059
6 1999-02-26 1.577058
7 1981-03-03 1.588790
8 1997-02-19 1.589288
9 2017-02-10 1.606338
10 1985-02-19 1.635733
11 1992-02-23 1.641926
12 1980-02-27 1.646186
13 2002-02-20 1.649281
14 1998-02-26 1.650298



The daily rankings are:

extent SH
2007-02-10 2.902966
1981-02-10 2.878055
1985-02-10 2.794707
2016-02-10 2.752291
1984-02-10 2.726681
2006-02-10 2.640735
2011-02-10 2.574753
1997-02-10 2.487675
1993-02-10 2.462680
2017-02-10 2.308883
area SH
1999-02-10 1.833285
1985-02-10 1.825640
1982-02-10 1.825003
1981-02-10 1.778675
1984-02-10 1.775469
1997-02-10 1.750999
2006-02-10 1.695252
2000-02-10 1.691211
2017-02-10 1.606338
1993-02-10 1.386590

Lord M Vader

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Re: Sea Ice Extent around Antarctica
« Reply #449 on: February 11, 2017, 10:52:29 PM »
Interstingly, University of Bremen ranks 2017 behind 1993. And from their time series, 2017 will most likely not beat 1993. 1997 is not represented in their graphs so we can't know how if 2017 is ahead or behind that year.

If a record low is going to be possible, that big blob of weak ice in Amundsen Sea needs to a big hit the next couple of days! Earliest date for the freezing onset is February 15 (1994) while the latest date is March 6 (1986).