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Author Topic: Sea Ice Extent around Antarctica  (Read 139289 times)

Wipneus

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Re: Sea Ice Extent around Antarctica
« Reply #750 on: October 27, 2017, 08:29:06 AM »
Updating NSIDC NT extent and area: the way down has not really been found yet.

Unfortunately posting any graph gives:

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Wipneus

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Re: Sea Ice Extent around Antarctica
« Reply #751 on: October 27, 2017, 03:13:51 PM »
Well, today both graphs seem to be accepted. Same comment: no on the way down yet.

steve s

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Re: Sea Ice Extent around Antarctica
« Reply #752 on: October 27, 2017, 11:24:53 PM »
Is there any time series tracking ice thickness or volume?

gerontocrat

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Re: Sea Ice Extent around Antarctica
« Reply #753 on: October 28, 2017, 02:58:20 PM »
Is there any time series tracking ice thickness or volume?
I have not found one. Perhaps 'tis because most Antarctic sea ice is First year, i.e. melts every year.

JAXA DATA

So far the story this year (to 27th October) is of very low extent loss since maximum, being 0.61 million km2 as opposed to the 10 year average of 1.19 million km2. This is the opposite of 2016, which had an extent loss of 1.8 million km2 by this date.
Only 2008-09 had a lower extent loss (0.47 million km2) at this date.
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gerontocrat

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Re: Sea Ice Extent around Antarctica
« Reply #754 on: October 31, 2017, 03:36:47 PM »
Has the Antarctic melting season got properly underway at last?
We are almost at the point when 2016 melting went doo-lally. What will happen this year?
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gerontocrat

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Re: Sea Ice Extent around Antarctica
« Reply #755 on: November 05, 2017, 03:20:17 PM »
JAXA DATA

the Antarctic melting season HAS got properly underway at last, but whether it will match 2016 is very much an open question.
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gerontocrat

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Re: Sea Ice Extent around Antarctica
« Reply #756 on: November 06, 2017, 12:49:13 PM »
JAXA DATA

On this date one year ago Antarctic sea ice extent became the lowest in the satellite record. At the moment this is not being repeated.

On 6th October 2017 extent exceeded 2016 extent by 51,815 km2. That difference has increased to 707,854 km2 (4.4%). (5th November extent is 16,696,169 km2).
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Wipneus

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Re: Sea Ice Extent around Antarctica
« Reply #757 on: November 06, 2017, 04:45:09 PM »
Update of the NSIDC NT extent and area graphs. The way down has been found, area is among the lowest years again.

Pavel

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Re: Sea Ice Extent around Antarctica
« Reply #758 on: November 10, 2017, 08:40:56 AM »
Hycom thickness product is now available for Antarctica

gerontocrat

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Re: Sea Ice Extent around Antarctica
« Reply #759 on: November 10, 2017, 01:28:35 PM »
Hycom thickness product is now available for Antarctica
Gosh - that is rather good - thick ice and strong northward drift  along Larsen C and then North East out of the Weddel Sea? Due to Weddell Sea Gyre posted by AbruptSLR?
Meanwhile:-
JAXA DATA

Average extent loss per day 125K km2 for the last 6 days. But not as much as 2016.

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gerontocrat

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Re: Sea Ice Extent around Antarctica
« Reply #760 on: November 14, 2017, 02:10:23 PM »
JAXA DATA

Antarctic sea ice extent continues to decline at well above average but below that of 2016. The table below shows the variation compared with the previous 3 years. Extent at  15,510,324 km2 is some 270,000 less than the low year of 2002, but to put this in perspective, this is about 2 days average extent loss at this time of year.
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Wipneus

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Re: Sea Ice Extent around Antarctica
« Reply #761 on: November 14, 2017, 05:03:59 PM »
Updating the NSIDC NT extent and area graphs. Both are second lowest for the day of year (but far above 2016 still).

gerontocrat

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Re: Sea Ice Extent around Antarctica
« Reply #762 on: November 20, 2017, 03:32:58 PM »
JAXA DATA as at 19 Nov 2017

Extent loss is still proceeding at well above average, but less than in 2016, which was just under 1.1 million km2 less at this date.
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Re: Sea Ice Extent around Antarctica
« Reply #763 on: November 20, 2017, 03:44:41 PM »
Tough to catch up to 2016's very early start.  But angle of descent is now equal to or even slightly greater than 2016.  PDS (pretty damn steep)....😳
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gerontocrat

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Re: Sea Ice Extent around Antarctica
« Reply #764 on: November 23, 2017, 01:26:15 PM »
JAXA DATA Antarctic Sea Ice Extent as at 22 Nov 2017.

Extent loss continues above average. The table below suggests a very low extent minimum is possible. However, on average extent loss is only 22% complete.

Note also (Jaxa image below) that the large polynya in the Weddell Sea is about to disappear. Will it reappear in the 2018 freezing season?
« Last Edit: November 23, 2017, 01:32:24 PM by gerontocrat »
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prokaryotes

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Re: Sea Ice Extent around Antarctica
« Reply #765 on: November 25, 2017, 06:29:12 PM »
So the last couple of years, sea ice progressively gets worse. What could this mean for glaciers? Are we seeing the beginning of a ramp up of ice retreat in Antarctica?

gerontocrat

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Re: Sea Ice Extent around Antarctica
« Reply #766 on: December 02, 2017, 03:45:04 PM »
So the last couple of years, sea ice progressively gets worse. What could this mean for glaciers? Are we seeing the beginning of a ramp up of ice retreat in Antarctica?
JAXA DATA as at 30 Nov

With sea ice extent loss only about 30 percent done the outcome is anybody's guess. Hence the fascination. However, we are at maximum insolation in the southern hemisphere, so with extent at 2nd or 3rd lowest some additional warming of surface water is possible - BUT on the other hand apparently this additional open water may also allow upwelling of warmer water from depth to the surface thus reducing melt of the ice shelves and glaciers from underneath.
« Last Edit: December 02, 2017, 03:50:05 PM by gerontocrat »
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gerontocrat

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Re: Sea Ice Extent around Antarctica
« Reply #767 on: December 03, 2017, 02:12:14 PM »
Image is from NSIDC at 2 Dec.

Weddell sea polynya about to become open sea.
Most of lower than average extent confined to eastern part of Weddell Sea.
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AbruptSLR

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Re: Sea Ice Extent around Antarctica
« Reply #768 on: December 04, 2017, 01:21:33 AM »
Image is from NSIDC at 2 Dec.

Weddell sea polynya about to become open sea.
Most of lower than average extent confined to eastern part of Weddell Sea.

I note that the indicated Antarctic sea ice extent pattern would not be surprising if recent (in the past few years) ice mass loss from Greenland were causing a cold spot in the North Atlantic to cause the MOC to convey more ocean heat to the Weddell Sea region due to the bipolar seesaw mechanism.
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gerontocrat

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Re: Sea Ice Extent around Antarctica
« Reply #769 on: December 07, 2017, 03:27:38 PM »
JAXA DATA as at 6 Dec 2017

On average just under 40% of extent loss is done (compared with 66% of arctic sea ice gain done).
The table below indicates that if history was a judge (!?) another very low minimum is on the cards.

However the graph below shows how individual years can vary and do vary wildly from the average.

The image from NSIDC also shows the disintegration of the sea ice as maximum melt gets underway, and that extent loss above average  is still mainly confined to the Eastern half of the Weddell Sea.

NOTE:- NSIDC seems to have moved the daily images to http://nsidc.org/arcticseaicenews/2012/05/daily-image/

strange but true.
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Paddy

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Re: Sea Ice Extent around Antarctica
« Reply #770 on: December 11, 2017, 08:49:21 AM »
What was the JAXA 2017 minimum? I'm looking at doing another poll.