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Buddy

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Re: Sea Ice Extent around Antarctica
« Reply #550 on: March 05, 2017, 04:08:34 PM »
Having the earliest top on record in August....and the latest bottom on record some time this month.....is NOT a good combo.😥I
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Thomas Barlow

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Re: Sea Ice Extent around Antarctica
« Reply #551 on: March 05, 2017, 04:19:19 PM »
Was Friday a double-whammy record for the Antarctic ?
Lowest sea-ice extent on record, and also the latest autumn rebound on record.
(black line = 1991 – previous record latest rebound. )

Buddy

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Re: Sea Ice Extent around Antarctica
« Reply #552 on: March 05, 2017, 05:04:24 PM »
One other thing to note about "bottoms" in general....both the Arctic AND Antarctic.....is that at some point.....maybe within 5 years....those bottoms will "broaden".  And they will broaden because they will BOTH start earlier AND end later.  And as we "run out of ice".....that "flat bottom" HAS to occur.

What will Joe Bastardi say then?  Inquiring minds want to know...  Poor little Joe... :o
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Lord M Vader

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Re: Sea Ice Extent around Antarctica
« Reply #553 on: March 05, 2017, 05:53:01 PM »
Thomas Barlow: No, there was an even later rebound in 1986 when the official minimum date was March 6. The second latest rebound was March 3 back in 2003. This years minimum is very likely a tie with second latest rebound behind 1986. Since March 1 the daily gain have been almost 70K and nothing indicate that there will be any loss the next few days in the SIE around Antarctica.

The most interesting question now is how quick the refreezing will be and if we are going to see any significant polar amplification given the very long period with open waters around Antarctica which has allowed heat to penetrate down into the sea.
 

magnamentis

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Re: Sea Ice Extent around Antarctica
« Reply #554 on: March 05, 2017, 06:07:47 PM »
One other thing to note about "bottoms" in general....both the Arctic AND Antarctic.....is that at some point.....maybe within 5 years....those bottoms will "broaden".  And they will broaden because they will BOTH start earlier AND end later.  And as we "run out of ice".....that "flat bottom" HAS to occur.

What will Joe Bastardi say then?  Inquiring minds want to know...  Poor little Joe... :o

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Thomas Barlow

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Re: Sea Ice Extent around Antarctica
« Reply #555 on: March 05, 2017, 08:43:29 PM »
Thomas Barlow: No, there was an even later rebound in 1986 when the official minimum date was March 6. The second latest rebound was March 3 back in 2003...The most interesting question now is how quick the refreezing will be and if we are going to see any significant polar amplification given the very long period with open waters around Antarctica which has allowed heat to penetrate down into the sea.

Ok. Good.
Thanks.
I thought we were in uncharted territory for a minute there.

« Last Edit: March 05, 2017, 08:48:44 PM by Thomas Barlow »

Wipneus

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Re: Sea Ice Extent around Antarctica
« Reply #556 on: March 06, 2017, 11:10:56 AM »
Small gains in the sea ice concentration data from Uni Bremen.

Regional Antarctic Sea Ice Extent and Area calculated from Uni Bremen ASI AMSR2 concentration data
See ub_am2_3.125_ant.txt for more details
Date: 2017-03-05 12:00  Values in 1000 km^2

Extent (value, one day change):
Bellingshausen&Amundsen Seas                   Weddel Sea
                230.7   +4.8                1247.9   +5.4
                Indian Ocean           West Pacific Ocean
                137.3   +2.3                 431.9   +4.1
                    Ross Sea                        Total
                121.4  +11.2                2169.3  +27.7

Area (value, one day change):
Bellingshausen&Amundsen Seas                   Weddel Sea
                185.9   +4.7                1108.5  -11.9
                Indian Ocean           West Pacific Ocean
                109.7   +0.1                 363.8   +3.5
                    Ross Sea                        Total
                 89.0  +15.8                1856.9  +12.2

crandles

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Re: Sea Ice Extent around Antarctica
« Reply #557 on: March 06, 2017, 12:38:17 PM »
JAXA:
12232,2017,02,28,1209513600,2151409
12233,2017,03,01,1209600000,2147345
12234,2017,03,02,1209686400,2149610
12235,2017,03,03,1209772800,2159375
12236,2017,03,04,1209859200,2168927
12237,2017,03,05,1209945600,2187029

only 40k above minimum but given: how late in season, usual smoothness of SH and 4 consecutive days of gains, I think we can call the minimum was 1st March.

Wipneus

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Re: Sea Ice Extent around Antarctica
« Reply #558 on: March 06, 2017, 02:25:29 PM »
Yes, NSIDC SIC says basically the same. Out of the minimum, but as long as the gains are this slow, extent stays well below the rest of the "pack".

Regional Antarctic Sea Ice Extent and Area calculated from NSIDC NASA Team concentration data
Date: 2017-03-05 12:00  Values in 1000 km^2

Extent (value, one day change, anomaly):
Bellingshausen&Amundsen Seas                   Weddel Sea
        220.1   -6.2  -246.2        1245.4  +18.8   -40.3
                Indian Ocean           West Pacific Ocean
        106.8   +3.1   -92.7         500.3   +9.1  +118.8
                    Ross Sea                        Total
         87.1   -5.9  -810.6        2159.7  +18.9 -1071.0

Area (value, one day change, anomaly):
Bellingshausen&Amundsen Seas                   Weddel Sea
        128.7  +10.3  -139.4        1004.8   +7.3   +21.9
                Indian Ocean           West Pacific Ocean
         53.8   +2.9   -42.4         297.2  +11.2   +77.3
                    Ross Sea                        Total
         32.8   -0.6  -470.4        1517.4  +31.2  -552.9



Bill Fothergill

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Re: Sea Ice Extent around Antarctica
« Reply #559 on: March 07, 2017, 01:32:06 AM »
Here are two "cut-down" versions of NSIDC's rolling 5-day Charctic for the Antarctic sea ice extent with data up to the 5th March. The first concentrates on the next 5 or 6 weeks, whilst the second looks at the period from late May until mid November. (By which time, 2016 had already firmly moved into "lowest value for the date".)

There's a few things that one can pull out (starting with the first attachment)...

1) After its "moment in the sun", 1997 (dark green) starts to fade into the pack. (And stays near the median for the rest of the year.)

2) 1993 (orange) has "lowest ever value for the date" until the 11th of March. However, over the following two weeks, it grows with extreme rapidity until it gets very close to the median value. (And stays around the median for the remainder of the year.)

3) Although 2016 (reddish) initially rises rapidly, such that it exceeds the median by around the 22nd March, it subsequently drops pretty low from mid-September onward. (That means there is a distinct possibility that the rolling annual average will plummet over the next few months.)

4) 2006 (purplish) has "lowest ever value for the date" between the 12th and 23rd of March, but ends up being outside the highest interdecile range by mid-August.

5) 1980 (yellow) then has the "lowest ever value for the date" until almost the end of May.

6) Looking at the second chart (end of May until mid November), for most of this period, 1980 continues to share "bottom billing", along with 1986 and 2002. (A few years briefly interrupt this three-way hegemony, but there's little to be gained by adding the additional "clutter".) However, by November 5th, 2016 moves into uncharted territory.
(Which is where we've been ever since.)

Wipneus

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Re: Sea Ice Extent around Antarctica
« Reply #560 on: March 07, 2017, 08:06:39 AM »
Not much freezing in the Uni Bremen AMSR2 sea ice concentration.

Regional Antarctic Sea Ice Extent and Area calculated from Uni Bremen ASI AMSR2 concentration data
See ub_am2_3.125_ant.txt for more details
Date: 2017-03-06 12:00  Values in 1000 km^2

Extent (value, one day change):
Bellingshausen&Amundsen Seas                   Weddel Sea
                238.8   +7.3                1242.7   -7.2
                Indian Ocean           West Pacific Ocean
                139.7   +1.3                 442.0   +8.6
                    Ross Sea                        Total
                111.0  -11.3                2174.3   -1.4

Area (value, one day change):
Bellingshausen&Amundsen Seas                   Weddel Sea
                191.3   +4.8                1088.9  -21.2
                Indian Ocean           West Pacific Ocean
                109.1   -1.5                 364.6   -0.5
                    Ross Sea                        Total
                 79.2  -10.4                1833.0  -28.7

Wipneus

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Re: Sea Ice Extent around Antarctica
« Reply #561 on: March 07, 2017, 01:59:45 PM »
NSIDC agrees.

Regional Antarctic Sea Ice Extent and Area calculated from NSIDC NASA Team concentration data
Date: 2017-03-06 12:00  Values in 1000 km^2

Extent (value, one day change, anomaly):
Bellingshausen&Amundsen Seas                   Weddel Sea
        231.0  +10.8  -239.1        1249.9   +4.5   -49.3
                Indian Ocean           West Pacific Ocean
        102.5   -4.3   -95.3         504.6   +4.3  +118.1
                    Ross Sea                        Total
         74.8  -12.3  -844.1        2162.7   +3.1 -1109.7

Area (value, one day change, anomaly):
Bellingshausen&Amundsen Seas                   Weddel Sea
        118.4  -10.2  -150.6        1019.1  +14.2   +29.4
                Indian Ocean           West Pacific Ocean
         53.3   -0.6   -43.3         295.3   -1.9   +72.3
                    Ross Sea                        Total
         28.5   -4.4  -491.4        1514.6   -2.8  -583.5

Darvince

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Re: Sea Ice Extent around Antarctica
« Reply #562 on: March 07, 2017, 10:28:15 PM »
JAXA, on the other hand, has started moving up more rapidly:


DrTskoul

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Re: Sea Ice Extent around Antarctica
« Reply #563 on: March 07, 2017, 10:44:57 PM »
 :o :o
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Wipneus

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Re: Sea Ice Extent around Antarctica
« Reply #564 on: March 08, 2017, 08:18:00 AM »
A small drop in extent according to Bremen AMSR2 sea ice concentration.

Regional Antarctic Sea Ice Extent and Area calculated from Uni Bremen ASI AMSR2 concentration data
See ub_am2_3.125_ant.txt for more details
Date: 2017-03-07 12:00  Values in 1000 km^2

Extent (value, one day change):
Bellingshausen&Amundsen Seas                   Weddel Sea
                238.4   -1.5                1276.3  +31.2
                Indian Ocean           West Pacific Ocean
                134.6   -6.5                 420.6  -23.1
                    Ross Sea                        Total
                104.4   -7.4                2174.3   -7.2

Area (value, one day change):
Bellingshausen&Amundsen Seas                   Weddel Sea
                192.5   +0.6                1126.5  +35.6
                Indian Ocean           West Pacific Ocean
                105.5   -4.6                 360.0   -6.0
                    Ross Sea                        Total
                 72.4   -7.3                1857.0  +18.3

Darvince

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Re: Sea Ice Extent around Antarctica
« Reply #565 on: March 08, 2017, 09:16:21 AM »
What is JAXA seeing? They record a 47,514 km2 increase for yesterday.

2017-03-07: 2245025
2017-03-06: 2197511

Wipneus

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Re: Sea Ice Extent around Antarctica
« Reply #566 on: March 08, 2017, 03:30:44 PM »
Refreezing according to NSIDC sea ice concentration was slow in the latest data.

Regional Antarctic Sea Ice Extent and Area calculated from NSIDC NASA Team concentration data
Date: 2017-03-07 12:00  Values in 1000 km^2

Extent (value, one day change, anomaly):
Bellingshausen&Amundsen Seas                   Weddel Sea
        207.0  -24.0  -274.0        1292.4  +42.5   -13.0
                Indian Ocean           West Pacific Ocean
        112.2   +9.7   -91.3         471.1  -33.5   +76.4
                    Ross Sea                        Total
         82.6   +7.8  -864.0        2165.3   +2.5 -1166.0

Area (value, one day change, anomaly):
Bellingshausen&Amundsen Seas                   Weddel Sea
        100.9  -17.6  -172.9        1051.5  +32.4   +56.4
                Indian Ocean           West Pacific Ocean
         56.8   +3.5   -42.7         278.7  -16.6   +51.2
                    Ross Sea                        Total
         32.8   +4.3  -510.4        1520.5   +6.0  -618.5

Wipneus

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Re: Sea Ice Extent around Antarctica
« Reply #567 on: March 09, 2017, 07:17:18 AM »
Bremen AMSR2 sea ice concentration shows solid increases for the first time.

Regional Antarctic Sea Ice Extent and Area calculated from Uni Bremen ASI AMSR2 concentration data
See ub_am2_3.125_ant.txt for more details
Date: 2017-03-08 12:00  Values in 1000 km^2

Extent (value, one day change):
Bellingshausen&Amundsen Seas                   Weddel Sea
                242.1   +2.2                1338.6  +61.1
                Indian Ocean           West Pacific Ocean
                137.7   +2.2                 446.5  +23.8
                    Ross Sea                        Total
                106.3   +1.1                2271.2  +90.5

Area (value, one day change):
Bellingshausen&Amundsen Seas                   Weddel Sea
                194.8   +1.5                1201.5  +74.2
                Indian Ocean           West Pacific Ocean
                107.2   +1.2                 371.4   +9.7
                    Ross Sea                        Total
                 70.8   -2.2                1945.8  +84.3

Lord M Vader

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Re: Sea Ice Extent around Antarctica
« Reply #568 on: March 09, 2017, 08:14:27 AM »
Your numbers confirmed my analyze after eyeballing todays SIE map, Wipneus. Weddell Sea is showing significant visible refreezing on the map. This should continue over the next couple of days as the forecast calls for continously cold or very cold weather in the southeast part of Weddell Sea. Overall, cold weather is foreseen to dominate over the next 5 days over most of Antarctica. The exception is the area from Ross Sea to Bellingshausen Sea where warmer than normal temperatures will prevail which should limit the ice growth there. Once these warm anomalies will be replaced by cold air from the interior of Antarctica we should see a rapid or very rapid ice growth.

Pavel

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Re: Sea Ice Extent around Antarctica
« Reply #569 on: March 09, 2017, 08:24:42 AM »
Anyway the ice-free Ross sea is a bad thing for the freezing season. It's usually one of the first area to start to refreeze and to export it's ice pack further. No ice yet, low albedo, extra heat have been (and still) accumulated, MYI has gone, there are no ice to be exported

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Re: Sea Ice Extent around Antarctica
« Reply #570 on: March 09, 2017, 01:58:14 PM »
And NSIDC more or less confirms:

Regional Antarctic Sea Ice Extent and Area calculated from NSIDC NASA Team concentration data
Date: 2017-03-08 12:00  Values in 1000 km^2

Extent (value, one day change, anomaly):
Bellingshausen&Amundsen Seas                   Weddel Sea
        211.6   +4.6  -277.8        1308.9  +16.5    -4.5
                Indian Ocean           West Pacific Ocean
        114.7   +2.5   -98.5         514.7  +43.6  +109.9
                    Ross Sea                        Total
        104.1  +21.5  -871.9        2253.9  +88.7 -1142.8

Area (value, one day change, anomaly):
Bellingshausen&Amundsen Seas                   Weddel Sea
        104.4   +3.6  -174.4        1078.7  +27.2   +77.3
                Indian Ocean           West Pacific Ocean
         58.5   +1.7   -44.6         302.9  +24.2   +70.1
                    Ross Sea                        Total
         38.3   +5.6  -529.5        1582.8  +62.2  -601.2

gerontocrat

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Re: Sea Ice Extent around Antarctica
« Reply #571 on: March 13, 2017, 02:53:31 PM »
Refreezing somewhat slower than last year. Jaxa extent measurement now over 1 million km2 less than 2016. SST anomalies still high north of antarctic circle but air temps below average. Early days but worth watching refreezing season.

bairgon

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Re: Sea Ice Extent around Antarctica
« Reply #572 on: March 13, 2017, 03:08:35 PM »
4 days out on Nullschool - 17th March - there is a fairly strong and warm northerly blowing on the Weddell Sea. This lasts for about a day and might cause some compaction of the spreading ice at the periphery, lowering the area.

https://earth.nullschool.net/#2017/03/17/2100Z/wind/surface/level/overlay=temp/orthographic=-6.32,-83.08,1203/loc=-53.832,-63.919

AbruptSLR

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Re: Sea Ice Extent around Antarctica
« Reply #573 on: March 14, 2017, 06:09:46 PM »
The linked reference discusses the tempo of changes in the hemispheric differences in sea ice distribution under different paleo radiative forcing conditions:

Jung-Eun Lee, Aaron Shen, Baylor Fox-Kemper & Yi Ming (27 January 2017), "Hemispheric sea ice distribution sets the glacial tempo", Geophysical Research Letters, DOI: 10.1002/2016GL071307

http://onlinelibrary.wiley.com/doi/10.1002/2016GL071307/full

Abstract: "The proxy record of global temperature shows that the dominant periodicity of the glacial cycle shifts from 40 kyr (obliquity) to 100 kyr (eccentricity) about a million years ago. Using climate model simulations, here we show that the pace of the glacial cycle depends on the pattern of hemispheric sea ice growth. In a cold climate the sea ice grows asymmetrically between two hemispheres under changes to Earth's orbital precession, because sea ice growth potential outside of the Arctic Circle is limited. This difference in hemispheric sea ice growth leads to an asymmetry in absorbed solar energy for the two hemispheres, particularly when eccentricity is high, even if the annual average insolation is similar. In a warmer climate, the hemispheric asymmetry of the sea ice decreases as mean Arctic and Antarctic sea ice decreases, diminishing the precession and eccentricity signals and explaining the dominant obliquity signal (40 kyr) before the mid-Pleistocene transition."
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Bill Fothergill

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Re: Sea Ice Extent around Antarctica
« Reply #574 on: March 14, 2017, 07:22:29 PM »
The linked reference discusses the tempo of changes in the hemispheric differences in sea ice distribution under different paleo radiative forcing conditions:
...
Abstract: "The proxy record of global temperature shows that the dominant periodicity of the glacial cycle shifts from 40 kyr (obliquity) to 100 kyr (eccentricity) about a million years ago.
...

When I read the above, it sounded vaguely familiar. (Everything is vague to me these days :()

The wiki entry on the Quaternary Glaciation contains the following text...
"... During the Quaternary Period, the total volume of land ice, sea level, and global temperature has fluctuated initially on 41,000- and more recently on 100,000-year time scales, as evidenced most clearly by ice cores for the past 800,000 years and marine sediment cores for the earlier period ..."

https://en.wikipedia.org/wiki/Quaternary_glaciation

Nice to see some agreement.

Bill Fothergill

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Re: Sea Ice Extent around Antarctica
« Reply #575 on: March 14, 2017, 08:22:06 PM »
Here's what things look like using ADS/Vishop (ver 2).

As usual, it's zoomed and filtered so that just the relevant low-ball years are displayed.

One thing perhaps worth noting is the gap between the extent on 13th March this year and that recorded last year - currently sitting at around -1.1 million sq kms. It doesn't take an Einstein to realise that, as long as the gap stays roughly similar, the rolling 365-day average will drop by ~ 3k sq kms each day.

The current (13 Mar 2017) rolling 365-day average using the ADS data stands at ~11.002 million sq kms, and should therefore drop below 11 million tomorrow.

There are some data drops which require infill and the measurement periodicity alters, but, if my technique was at all reasonable [  :-\ ] the previous low for this metric was 11.090 million sq kms. This was clocked up around early August 1980.

NB Using the NSIDC figures for Antarctic extent, the current rolling 365-day value is ~11.027 million sq kms, still some way above the equivalent value of 10.969 million sq kms recorded for early August 1980. Should the gap between this year and last year remain much the same, it will take about ~ 20 days to reach this record low value.


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Re: Sea Ice Extent around Antarctica
« Reply #576 on: March 17, 2017, 07:12:22 AM »
From the Arctic 2017 melting season thread:

Antarctic Sea Ice is doing what the Arctic sea ice did this last fall and winter.

https://seaice.uni-bremen.de/data/amsr2/today/extent_s_running_mean_amsr2_regular.png

Those northerly winds are starting to blow on Weddell:

17th March - there is a fairly strong and warm northerly blowing on the Weddell Sea.

Wipneus, any chance of daily updates on area for each region again?


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Re: Sea Ice Extent around Antarctica
« Reply #578 on: March 17, 2017, 10:05:20 AM »
A small observation:-
On March 16 2017 jaxa measurement says antarctic sea ice 1/3 rd less than on March 16 2017. Difference currently increasing every day.

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Re: Sea Ice Extent around Antarctica
« Reply #579 on: March 17, 2017, 11:14:23 AM »
Antarctic Uni Hamburg data is here:

Thanks for the links. I had browsed the start page and site map for your site but couldn't find links to this data.

It appears that the Ross sea, and to a lesser extent the Weddel sea are the main reason for the slow growth.

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Re: Sea Ice Extent around Antarctica
« Reply #580 on: March 17, 2017, 02:30:51 PM »
A small observation:-
On March 16 2017 jaxa measurement says antarctic sea ice 1/3 rd less than on March 16 2017. Difference currently increasing every day.


A)  Good observation
B)  That is HUGE....not small. ;)

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Re: Sea Ice Extent around Antarctica
« Reply #581 on: March 17, 2017, 03:31:20 PM »
perhaps those should be 2 different dates ? .. gerontocrat / Buddy ? Perhaps 2014 was the comparison ?

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Re: Sea Ice Extent around Antarctica
« Reply #582 on: March 17, 2017, 03:51:01 PM »
perhaps those should be 2 different dates ? .. gerontocrat / Buddy ? Perhaps 2014 was the comparison ?

1)  I think he meant 2016 (last year).  Sloppy of ME not to catch that. Good catch by you. ;D

2)  Difference is actually 30% (but 30% vs 33% is immaterial).

What I was READING was 2017 compared to 2016.  And a 30% or 33% difference is a BIG DEAL.  I "believe" that is what he meant...

2.56 = 2017
3.68 = 2016
1.12 = Difference....which is 30% less than 2016....





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Bill Fothergill

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Re: Sea Ice Extent around Antarctica
« Reply #583 on: March 17, 2017, 05:08:28 PM »
A small observation:-
On March 16 2017 jaxa measurement says antarctic sea ice 1/3 rd less than on March 16 2017 [2016]. Difference currently increasing every day.

If you look further up the page at #559, point No 3, you'll get a foretaste of how that might progress...

"3) Although 2016 (reddish) initially rises rapidly, such that it exceeds the median by around the 22nd March, it subsequently drops pretty low from mid-September onward. (That means there is a distinct possibility that the rolling annual average will plummet over the next few months.)"

Although that related to NSIDC figures, the IJIS/JAXA/ADS numbers are pretty similar. By the 24th March, the 2016 figures had already reached and exceeded all of the 3 decadal averages.

There is a bit more on the IJIS/JAXA/ADS numbers at #575.

Given the extreme variability demonstrated by the Antarctic in the past, I'm still adopting a "wait and see" viewpoint.

Meanwhile, in a place quite literally poles apart from the Arctic, things are moving in the opposite direction - in every sense...
...
I think it's too early to say if this is purely down to specific weather conditions, or whether the sea ice in the Antarctic is starting to respond to climate change in an analogous fashion to its boreal cousin. However, a watching brief is definitely in order.

However, there is some evidence to suggest that a switch in the Interdecadal Pacific Oscillation has kicked in. See here...

https://www.carbonbrief.org/pacific-ocean-behind-recent-antarctic-sea-ice-growth-study-says

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Re: Sea Ice Extent around Antarctica
« Reply #584 on: March 17, 2017, 06:49:14 PM »
can someone cut and paste that article? my browser will not open it because it considers the server insecure.

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Re: Sea Ice Extent around Antarctica
« Reply #585 on: March 17, 2017, 06:57:47 PM »
I suggest that you read what NSIDC has in their FAQ about Antarctica: http://nsidc.org/arcticseaicenews/faq/#wintertimeantarctic

I think their explanation fits fairly well to explain the exceptionally low SIE we have seen this season, and I agree with Bill, we have to wait and see what happens in the coming years given the very large yearly variability.


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Re: Sea Ice Extent around Antarctica
« Reply #586 on: March 17, 2017, 10:48:55 PM »
...we have to wait and see what happens in the coming years given the very large yearly variability.
And given Hansen's feedback of melting glaciers resulting in increased sea ice around Antarctica. Should the WAIS mass loss continue to accelerate, there will be a large input of fresh cold water into the southern ocean. Very different from the Arctic, continent in the middle vs. ocean in the middle.

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Re: Sea Ice Extent around Antarctica
« Reply #587 on: March 18, 2017, 12:24:13 AM »
Should the WAIS mass loss continue to accelerate, there will be a large input of fresh cold water into the southern ocean. Very different from the Arctic, continent in the middle vs. ocean in the middle.

Yes. We also have increased strength of Westerlies resulting in increased Coriolis deflection, which obviously causes spreading in an equator-ward direction. In addition to that, the good old Clausius-Clapeyron relationship means that, thanks to the warming South Pacific, there will be a higher atmospheric moisture content, which in turn will lead to enhanced precipitation (snow and rain); both of these forms contribute to a temporary increase in sea ice area/extent.

... we have to wait and see what happens in the coming years given the very large yearly variability.

Possibly the best example I can think of to back up that statement comes from the NSIDC monthly figures for Antarctic sea ice area. The year 2006 still has the lowest value for March in that dataset - at least for the next few weeks. However, by August, it had grown to 2nd highest - although that month has since been equalled once, and beaten 3 times. September 2006 was actually, although briefly, the highest for that month, and has been surpassed on 4 occasions. October 2006 also had the "highest for that month" status, but now trails in the wake of 2013 & 2014.

Bizarrely, by December, 2006 had moved to 8th lowest area, and has only slipped one place since then.

That is why neither LMV or myself are getting carried away at the moment by developments down there.

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Re: Sea Ice Extent around Antarctica
« Reply #588 on: March 18, 2017, 07:44:49 AM »
And NSIDC more or less confirms:

Regional Antarctic Sea Ice Extent and Area calculated from NSIDC NASA Team concentration data
Date: 2017-03-08 12:00  Values in 1000 km^2

Extent (value, one day change, anomaly):
Bellingshausen&Amundsen Seas                   Weddel Sea
        211.6   +4.6  -277.8        1308.9  +16.5    -4.5
                Indian Ocean           West Pacific Ocean
        114.7   +2.5   -98.5         514.7  +43.6  +109.9
                    Ross Sea                        Total
        104.1  +21.5  -871.9        2253.9  +88.7 -1142.8

Area (value, one day change, anomaly):
Bellingshausen&Amundsen Seas                   Weddel Sea
        104.4   +3.6  -174.4        1078.7  +27.2   +77.3
                Indian Ocean           West Pacific Ocean
         58.5   +1.7   -44.6         302.9  +24.2   +70.1
                    Ross Sea                        Total
         38.3   +5.6  -529.5        1582.8  +62.2  -601.2


Thanks for these updates during the season.

Does anyone have the 2017 NSIDC/JAXA final lows (area, extent) and their comparison to the top ten previous years?

gerontocrat

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Re: Sea Ice Extent around Antarctica
« Reply #589 on: March 18, 2017, 01:41:45 PM »
Hullo Georged,

The only data I have is Jaxa's .CSV files on daily measures of Arctic and Antarctic sea ice extent. They are easily downloaded - I use Jaxa's version 1 as I find it easier to use for the very simple things I do (environmental arithmetic as opposed to real maths). The address is https://ads.nipr.ac.jp/vishop.ver1/vishop-extent.html?N

So I simply observe that Antarctic sea ice has been several standard deviations below the average in the satellite record  for some time. Methinks I was taught by my statistics tutor that the greater that deviation then the less likely it is that the observations were random chance. Which is why I still think keeping an eye on what's going on down south is of value.

But what were the causes of such massive variations from the "norm" ?
And what has been the effect on sea ice shelves exposed to open ocean in a way they have not been for a good many years?

And isn't it strange that we find that we know least about that which we find we need to know most? (Antarctica, the Oceans)

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Re: Sea Ice Extent around Antarctica
« Reply #590 on: March 18, 2017, 06:42:49 PM »
Today the 2017 NSIDC Antarctic area becomes lowest for the day.  1993 that was lowest at minimum by a wide margin is now #nine or so.

extent SH
1986-03-17 3.720040
1985-03-17 3.665129
1984-03-17 3.632114
2011-03-17 3.498813
1992-03-17 3.449271
1997-03-17 3.399628
1981-03-17 3.374994
1980-03-17 3.312352
2006-03-17 3.085380
2017-03-17 2.663219
area SH
1992-03-17 2.359388
1993-03-17 2.357730
1986-03-17 2.322920
1984-03-17 2.318267
2011-03-17 2.286173
1997-03-17 2.212859
1981-03-17 2.149549
1980-03-17 2.143683
2006-03-17 1.867773
2017-03-17 1.817864



Lord M Vader

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Re: Sea Ice Extent around Antarctica
« Reply #591 on: March 18, 2017, 09:50:36 PM »
The most interesting thing right now is how much impact the sun have had on the SSTs around the continent given the exceptionally low levels of SIE that have prevailed since the middle of November last year. The SIE maximum around Antarctica should most likely be quite normal by late summer/early fall but we might have a long period with SIE much below average.

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Re: Sea Ice Extent around Antarctica
« Reply #592 on: March 19, 2017, 06:44:41 PM »
The most interesting thing right now is how much impact the sun have had on the SSTs around the continent given the exceptionally low levels of SIE that have prevailed since the middle of November last year. The SIE maximum around Antarctica should most likely be quite normal by late summer/early fall but we might have a long period with SIE much below average.

since antarctica is not surrounded by land i predict that in the not so far future the austral winter numbers in antarctic sea-ice extent will drop significantly while in the arctic it will take some more time until the basin won't be more or less filled with ice.

last but not least land and ice-masses together keep that part cold in winter while warmer oceans will have their inmpact in the south rather directly.

this is not meant to happen under all circumstances already now (but it could) while i'm quite sure that the described scenario is not too far ahead if at all :-)
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Re: Sea Ice Extent around Antarctica
« Reply #593 on: March 21, 2017, 09:45:37 PM »
The most interesting thing right now is how much impact the sun have had on the SSTs around the continent given the exceptionally low levels of SIE that have prevailed since the middle of November last year. The SIE maximum around Antarctica should most likely be quite normal by late summer/early fall but we might have a long period with SIE much below average.
Sea temperatures from 60S -> 75S have been much warmer over the past two months than during the past decade. I expect this to continue to inhibit SIE growth leading to a near record low maximum this year.  My  early  prediction is that all four significant records for extent will fall this year, both the maximums and minimums for Arctic and Antarctic. This would be an effect of the significant rise in SSTs accompanying the recent El Nino

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Re: Sea Ice Extent around Antarctica
« Reply #594 on: March 23, 2017, 12:24:22 PM »
The re-freezing of Antarctica continues to impress by its slow pace. The current (March 22 Jaxa) measurement of extent of 3,038,106 sq km is now 1.3 million km2 less than the 1980s average (1980s being the lowest decade). This is an increased difference of 0.4 million compared with 20 days ago (the 2017 minimum).
As DavidR pointed out, SST anomalies as far north as 60 S currently point to this continuing (caveat: all other things being equal). So on a risk analysis approach given the available data, I can see no reason for this year's maximum not to be very low (even though the variability from year to year in Antarctica is extreme, meaning all predictions have a low probability of accuracy ?).

But, given the accumulated expertise gathered within ASIF, what do I know ?

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Re: Sea Ice Extent around Antarctica
« Reply #595 on: March 23, 2017, 03:13:11 PM »
The re-freezing of Antarctica continues to impress by its slow pace.

Not surprising.  It is.....of course.....hard to discern "intermediate trends" from "short term trends"....but the long term trend is certainly in place.  Right now.....warmish waters around Antarctica, especially in the Pacific.

 
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Re: Sea Ice Extent around Antarctica
« Reply #596 on: March 23, 2017, 05:08:22 PM »
Wipneus: NSIDC reported a 39K DROP in SIE for March 22. Do you, or anyone else here, know whether this is unheard of or at least unusual?

Which area contributed to the small decline?

//LMV

Bill Fothergill

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Re: Sea Ice Extent around Antarctica
« Reply #597 on: March 23, 2017, 06:37:54 PM »
Wipneus: NSIDC reported a 39K DROP in SIE for March 22. Do you, or anyone else here, know whether this is unheard of or at least unusual?

I think drops in (NSIDC) Antarctic extent during March have been recorded on 58 occasions. The arithmetic average of these drops is -28k, and the largest was -169k way back in 1979.

Between the 10th and 31st March, there have only been drops on 22 occasions.

Between them, April and May have seen 25 such drops. These averaged -22k, with the largest, -79k, happening in May 1986.

HOWEVER, those numbers need to be qualified by the fact that daily recording didn't start until September 1987. Therefore, those two "big" drops were actually two-day drops. On the other hand, the total number of days showing a drop would likely be somewhat higher.

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Re: Sea Ice Extent around Antarctica
« Reply #598 on: March 23, 2017, 06:53:59 PM »
Wipneus: NSIDC reported a 39K DROP in SIE for March 22. Do you, or anyone else here, know whether this is unheard of or at least unusual?

Which area contributed to the small decline?

//LMV

Regional Antarctic Sea Ice Extent and Area calculated from NSIDC NASA Team concentration data
Date: 2017-03-22 12:00  Values in 1000 km^2

Extent (value, one day change, anomaly):
Bellingshausen&Amundsen Seas                   Weddel Sea
        192.1   -2.5  -402.2        1550.5   -7.6   -49.4
                Indian Ocean           West Pacific Ocean
        192.4  -14.7  -138.4         593.3  -33.9   +72.0
                    Ross Sea                        Total
        415.3  +19.7 -1010.6        2943.6  -38.9 -1528.6

Area (value, one day change, anomaly):
Bellingshausen&Amundsen Seas                   Weddel Sea
         99.1   +0.7  -253.8        1155.8  -21.8   -73.2
                Indian Ocean           West Pacific Ocean
         78.0   -2.6   -95.1         355.0   -7.7   +54.1
                    Ross Sea                        Total
        208.6  +14.3  -762.5        1896.6  -17.1 -1130.7


This is actually the contents of:
https://sites.google.com/site/arctischepinguin/home/sea-ice-extent-area/data/nsidc_ant_nt_nrt_summary.txt

This is auto-updated daily.

If you need the regional data for other dates than the last the look here:
https://sites.google.com/site/arctischepinguin/home/sea-ice-extent-area/data/nsidc_ant_nt_detail.txt

Auto-updated as well.

Buddy

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Re: Sea Ice Extent around Antarctica
« Reply #599 on: March 24, 2017, 02:00:17 PM »
I am probably EQUALLY interested to see what the Antarctic MAXIMUM will be this coming August/Sept.....as I am to see what this September's Arctic MINIMUM will be.

The slowly warming oceans are clearly having an effect on both.  Another Antarctic record low MAXIMUM would be a very bad message indeed.  And if we head into another El Nino later this year...that would certainly not be good news.

I continue to watch Wip's total sea ice area map with intense interest.  Basic physics at work I'm afraid.



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