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Tigertown

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Re: Sea Ice Extent around Antarctica
« Reply #700 on: September 02, 2017, 10:40:06 AM »
Antarctica SIE right now reminds me of a staggering ole' drunk trying to stay on his feet.
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gerontocrat

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Re: Sea Ice Extent around Antarctica
« Reply #701 on: September 02, 2017, 02:11:42 PM »
Antarctic sea ice extent (JAXA data) reached a maximum of 17.640 million km2 on 25th August. 7 days later it is 125,000 km2 less at 17.515 million km2. In this period the average gain is 250,000 km2.
However, there are often big ups and downs in September, so a surprise may be in store either way, especially given average date of maximum is more like around the 20th September. If 25th August ends up as the date of maximum (2016 was on 29th August) - good heavens.

So, like a fool I will prognosticate a maximum extent of less than 18 million km2.

« Last Edit: September 02, 2017, 02:21:56 PM by gerontocrat »
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Tigertown

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Re: Sea Ice Extent around Antarctica
« Reply #702 on: September 03, 2017, 04:02:06 PM »
NSIDC SIE for Antarctica has really leveled off or stalled. JAXA is similar, but they have not updated for 9-2-2017 yet.
"....and the appointed time came for God to bring to ruin those ruining the earth." Revelation 11:18.

steve s

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Re: Sea Ice Extent around Antarctica
« Reply #703 on: September 03, 2017, 06:35:20 PM »
Looks to me like the sea ice extent took a step downward in August 2016, and stayed down thereafter. An energy distribution change of some kind. What other event or events may be time correlated?

I wrote 'may' because the other events may be earlier or later due to transmission effects and the cause may be a separate matter, but the step nature of the shift is clear. The shift is as interesting a phenomenon as it is frightening.   

Tigertown

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Re: Sea Ice Extent around Antarctica
« Reply #704 on: September 03, 2017, 07:08:49 PM »
Looks to me like the sea ice extent took a step downward in August 2016, and stayed down thereafter. An energy distribution change of some kind. What other event or events may be time correlated?

I wrote 'may' because the other events may be earlier or later due to transmission effects and the cause may be a separate matter, but the step nature of the shift is clear. The shift is as interesting a phenomenon as it is frightening.
Do you mean to say September 2016?
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steve s

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Re: Sea Ice Extent around Antarctica
« Reply #705 on: September 03, 2017, 07:43:04 PM »
Oops I was misreading where months begin in your graph. The change began around or just after the beginning of September 2016 and took 10 days to 2 weeks to complete, as I now read the graph.

gerontocrat

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Re: Sea Ice Extent around Antarctica
« Reply #706 on: September 04, 2017, 11:12:23 AM »
JAXA DATA

What an end of season at both ends of the earth.
Table 1 shows some possible outcomes, including August 25th as the maximum
On 5th Nov 2016 sea ice extent became the lowest in the satellite record, and stayed that way for over 150 days. Since then, apart from a few days at 4th lowest, extent has been 3rd, 2nd or 1st lowest. We are in the third year of significant decline. (see Table 2)

In 2016 extent dropped suddenly after 29th August - (see graph). Will 2017 follow this pattern?
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gerontocrat

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Re: Sea Ice Extent around Antarctica
« Reply #707 on: September 06, 2017, 11:12:11 AM »
With 3 days increase in extent, 5th September a wopping 189,000 km2, The maximum extent to date is now 17.72 km2, i.e. 25th August is NOT the date of maximum.
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AbruptSLR

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Re: Sea Ice Extent around Antarctica
« Reply #708 on: September 07, 2017, 05:39:40 PM »
I have the feeling that with continued climate change we had better get used to 'perfect storm' occurrences, as they will soon be common place events:

Title: "Record-low 2016 Antarctic sea ice due to 'perfect storm' of tropical, polar conditions"

http://www.spacedaily.com/reports/Record_low_2016_Antarctic_sea_ice_due_to_perfect_storm_of_tropical_polar_conditions_999.html
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steve s

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Re: Sea Ice Extent around Antarctica
« Reply #709 on: September 07, 2017, 07:23:30 PM »
Last year's sea ice extent a perfect storm of coincidences? Then why does this year seem so similar? I find it much easier to imagine a single driver than the squared product of low probabilities.

Buddy

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Re: Sea Ice Extent around Antarctica
« Reply #710 on: September 07, 2017, 09:53:20 PM »
Steve S.....absolutely right.  This is just the continuation of the basic physics in play.  And as temperatures continue to rise....along with sea levels....the science deniers will continue to mislead and lie.

FOX News has been lying about global warming for over 20 years.....and they were the biggest supporter of SCROTUS.

Donnie Trump, FOX, Bastardi, Hannity, Rick Scott, Mike Pence, Mitch McConell, Paul Ryan, Marco Rubio, etc.....

But to get back to your point.....I look for a continuation of the drop in global ice, and an acceleration of it...
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AbruptSLR

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Re: Sea Ice Extent around Antarctica
« Reply #711 on: September 08, 2017, 05:18:32 PM »
Obviously, the data presented in the linked article was taken before the Antarctic sea ice extent began to retreat last year:

Katlein, C., Hendricks, S., and Key, J.: Brief communication: Increasing shortwave absorption over the Arctic Ocean is not balanced by trends in the Antarctic, The Cryosphere, 11, 2111-2116, https://doi.org/10.5194/tc-11-2111-2017, 2017.

https://www.the-cryosphere.net/11/2111/2017/?utm_content=bufferf747e&utm_medium=social&utm_source=twitter.com&utm_campaign=buffer

Abstract. On the basis of a new, consistent, long-term observational satellite dataset we show that, despite the observed increase of sea ice extent in the Antarctic, absorption of solar shortwave radiation in the Southern Ocean poleward of 60° latitude is not decreasing. The observations hence show that the small increase in Antarctic sea ice extent does not compensate for the combined effect of retreating Arctic sea ice and changes in cloud cover, which both result in a total increase in solar shortwave energy deposited into the polar oceans.
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steve s

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Re: Sea Ice Extent around Antarctica
« Reply #712 on: September 08, 2017, 07:37:23 PM »
Not a surprising finding, ASLR; but there seems to have been a stair-step shift in sea ice extent, not the gradual change that article suggests. The cause of that step-wise shift begs explanation. We do not know whether the shift might repeat or the reason for its scale. Without gradualism, we are blinder than we knew.
« Last Edit: September 09, 2017, 06:12:20 PM by steve s »

gerontocrat

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Re: Sea Ice Extent around Antarctica
« Reply #713 on: September 09, 2017, 01:06:34 PM »
JAXA extent is now 17.85 million km2, i.e. increasing. Will the max be below 2016? If yes, then it will be three consecutive lower maxima from 2014.

I also attach an image from cci-reanalyzer of the 5 day max temp forecast, as it shows very well how those beautiful near perfect circles of temperature gradients are being disrupted as warmth returns.
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Re: Sea Ice Extent around Antarctica
« Reply #714 on: September 12, 2017, 07:11:57 PM »
It is still possible that 2017 will record lowest maximum extent and/or lowest maximum area.
But it is getting close, and the latest maximums were reached 3rd of October 1988.

Here are the year with lowest maximums:

SH Extent

35 2008-09-03 18.297985
36 1989-09-23 18.274455
37 2002-09-09 18.116289
38 1986-09-18 18.026832
39 2017-09-11 17.969850

SH Area

35 1979-09-05 14.515589
36 2016-08-28 14.493985
37 1984-09-04 14.493378
38 1986-09-18 14.177269
39 2017-09-08 14.104656

gerontocrat

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Re: Sea Ice Extent around Antarctica
« Reply #715 on: September 14, 2017, 12:47:42 PM »
JAXA Data
Extent on 13th Sept is 18.03 million km2.

On 12th September extent exceeded 2016 extent for the first time. Extent on 13th September  is now 0.2 million km2 greater than 2016 on that date.
On the other hand it still looks more likely that the 2017 maximum will be less than the 2016  maximum of 18.5 million on 29th August (see table).

For me the next two key events are
 - the maximum extent c.f. 2016,
- November 5th - on that date 2016 extent became the lowest in the satellite record. Will 2017 be the same?
"Para a Causa do Povo a Luta Continua!"
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Adam Ash

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Re: Sea Ice Extent around Antarctica
« Reply #716 on: September 14, 2017, 01:28:20 PM »
I have just re-read Hansen et al Ice melt, sea level rise and superstorms (2015).  Expansion of sea ice around Antartica is entirely in line with impacts of increased forcing due to CO2 et al.  The resulting increase in ice melt at both ends of the planet will lower sea surface temperatures there for a while, as well as reducing or stopping the major Meridional Overturning Circulations which screws heat distribution.  Then the increased atmospheric energy gradients (especially the much warmer equatorial regions) create storms of increasingly-unimaginable intensity. 
If we get a 'minimum maximum' around Antarctic this year I think it will be a blessing, but that's not what the forecast for the next few decades/centuries looks like, until ice melt slows again.

gerontocrat

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Re: Sea Ice Extent around Antarctica
« Reply #717 on: September 15, 2017, 03:06:43 PM »
The question for me is more immediate. Will 2017 continue the decline in extent started in 2014 or will it (as often happens) just merge into the pack?
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Tigertown

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Re: Sea Ice Extent around Antarctica
« Reply #718 on: September 15, 2017, 05:59:05 PM »
The question for me is more immediate. Will 2017 continue the decline in extent started in 2014 or will it (as often happens) just merge into the pack?
I think we will find out over the next two weeks where this season is going.
"....and the appointed time came for God to bring to ruin those ruining the earth." Revelation 11:18.

Wipneus

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Re: Sea Ice Extent around Antarctica
« Reply #719 on: September 15, 2017, 06:10:35 PM »
Detailed graphs of extent and area calculated from NSIDC NT sea ice concentration attached. I highlighted the 1986 curve as well: lowest extent and area minimum until this year...
Click for a bigger picture.
« Last Edit: September 15, 2017, 06:17:02 PM by Wipneus »

gerontocrat

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Re: Sea Ice Extent around Antarctica
« Reply #720 on: September 18, 2017, 03:00:57 PM »
JAXA DATA
Sea ice extent now only 50,000 km2 above 2016, and at its lowest since 10 days ago.
More likely that the 18.062 million km2 extent on 12th September will be the maximum extent.
But wobbles in extent often persist until end of September before significant melt occurs.
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Pavel

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Re: Sea Ice Extent around Antarctica
« Reply #721 on: September 18, 2017, 09:50:35 PM »
A polynya have been opening in Atlantic side. The animation from 12 to 17 September. Also cold anomalies forecasted in the Ross sea

gerontocrat

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Re: Sea Ice Extent around Antarctica
« Reply #722 on: September 20, 2017, 02:00:00 PM »
JAXA DATA
Sea ice extent now 100,000 km2 below 2016, and at its lowest since 12 days ago.
Even more likely that the 18.062 million km2 extent on 12th September will be the maximum extent.
But wobbles in extent often persist until end of September before significant melt occurs.
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gerontocrat

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Re: Sea Ice Extent around Antarctica
« Reply #723 on: September 22, 2017, 01:07:41 PM »
JAXA DATA
Extent continues to steadily decline. If it was not for the large late increase in 2015, methinks the maximum extent was definitely reached on 12 September at 18.062 million km2.
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Lord M Vader

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Re: Sea Ice Extent around Antarctica
« Reply #724 on: September 25, 2017, 07:31:51 PM »
Extent drops continues. The 5-day average from NSIDC might end up being the second lowest on record trailing 1986. However, the daily maximum might be the lowest on record with a razor thin margin of 4000 km2. Let's see how fast the extent numbers drop! :)

gerontocrat

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Re: Sea Ice Extent around Antarctica
« Reply #725 on: September 26, 2017, 03:31:23 PM »
JAXA DATA (Usually follows NSIDC very closely)
The continued decline in extent, despite -ve or neutral temp and SST anomalies, would make one think the 12 September extent of 18.062 million km2 was definitely the maximum, given that the date of maximum has passed for all years but one - 2015. Extent shot up from now to 2nd October. (see table). 2017 could do the same.

One might also think that 2017-2018 would continue to be a record or near record-low in daily extent. However, the previous record low maximum years of 1986 and 2002 flattered to deceive, extent gently moving into the pack as the melt season progressed. In contrast, the graph below shows how in early November 2016, extent dropped like a stone to the lowest in the satellie record and stayed there until April 2017.

The Antarctic is unpredictable.


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Wipneus

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Re: Sea Ice Extent around Antarctica
« Reply #726 on: September 26, 2017, 06:50:33 PM »
Update of the NSIDC graphs. Provisional maximums of area and extent are still record low, but new maximums cannot be ruled out yet (IMO).

gerontocrat

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Re: Sea Ice Extent around Antarctica
« Reply #727 on: September 27, 2017, 01:44:55 PM »
An interesting article as it makes clear that the priority is to assist the Antarctic Tourism industry.

https://www.theguardian.com/world/2017/sep/26/antarctic-sea-ice-levels-hit-record-low-but-experts-are-not-sure-why

Antarctic sea ice levels hit record low, but experts are not sure why

"Unpredictable nature of Antarctic sea ice levels the focus at conference of meteorology experts in Australia this week.

Better mapping and predicting these changes to aid polar shipping is the goal of the International Ice Charting Working Group Tasmanian meeting.

Unpredictable sea ice levels are creating headaches for an increasing number of tourist and research boats visiting the Antarctic.

The working group estimates about 50 cruise vessels took almost 35,000 tourists to the Antarctic last year."
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Re: Sea Ice Extent around Antarctica
« Reply #728 on: September 28, 2017, 03:00:55 PM »
An interesting article as it makes clear that the priority is to assist the Antarctic Tourism industry.

https://www.theguardian.com/world/2017/sep/26/antarctic-sea-ice-levels-hit-record-low-but-experts-are-not-sure-why

Antarctic sea ice levels hit record low, but experts are not sure why

"Unpredictable nature of Antarctic sea ice levels the focus at conference of meteorology experts in Australia this week.

Better mapping and predicting these changes to aid polar shipping is the goal of the International Ice Charting Working Group Tasmanian meeting.

Unpredictable sea ice levels are creating headaches for an increasing number of tourist and research boats visiting the Antarctic.

The working group estimates about 50 cruise vessels took almost 35,000 tourists to the Antarctic last year."

The sea ice levels have always been unpredictable.  Similar to the weather.

Gray-Wolf

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Re: Sea Ice Extent around Antarctica
« Reply #729 on: September 28, 2017, 10:33:29 PM »
I tend to think that we see periods of excessive growth when certain 'natural cycles' combine and less so under other forcings?

I think we have also been treated too, this past 40 years, a 'novel forcing' from the Ozone impacting the polar atmosphere?

We appear to now be in the 'less ice set up of Pacific 'cycles' and some repair of the Ozone?

On top of all that we have the warming that has been 'locked out' of Antarctica (over the period where naturals and ozone hole worked to expand Sea Ice?) that now appears to be working back into the Continent?

I think we have a few years of this low finish, high loss, high calving environment ahead?

I just hope we don't trip over any tipping points, esp around the Peninsula, if we do see a more 'arctic' version of Antarctica in terms of melt rates and sea ice cover?
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gerontocrat

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Re: Sea Ice Extent around Antarctica
« Reply #730 on: October 04, 2017, 11:37:18 AM »
JAXA DATA
The melting season is underway (although this year the sea ice extent has increased a bit in the last few days despite that polynya in the Weddell Sea that apparently indicates up-welling of major ocean heat from the depths ).

So I've been having a look at extent loss from max to min over the satellite record.

The main result is how small the variation from the average melt has been over the years. A maximum of +5% in 2005-06 and a minimum of -3% in 2007-08.

Whoops - error in table corrected

The second result is that the average melt in the last 10 years would result in a new record minimum extent in Feb/Mar 2018.

BUT I make no prediction - merely present the past for your edification.
« Last Edit: October 04, 2017, 11:48:21 AM by gerontocrat »
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Re: Sea Ice Extent around Antarctica
« Reply #731 on: October 04, 2017, 04:19:46 PM »
Update of the NSIDC NT graphics.

2017 still has the lowest maximums of all years. Extent has not moved very much in the last few weeks, but area seems now definitively going south (and is now the lowest for the date).

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Re: Sea Ice Extent around Antarctica
« Reply #732 on: October 04, 2017, 04:42:45 PM »
Wipneus'  graph on area shows significant recent loss as opposed to some extent gain. I was looking at JAXA's sea ice concentration images over recent days and weeks which seemed to also show significant loss of solidity over much of the sea ice.
The Antarctic could be the place to watch this month?
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Re: Sea Ice Extent around Antarctica
« Reply #733 on: October 04, 2017, 07:52:40 PM »
Most likely, the recent gains in extent were from dispersion and not much from re-freezing. When the extent starts to fall, it will probably move fast.
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Re: Sea Ice Extent around Antarctica
« Reply #734 on: October 06, 2017, 05:55:34 PM »
NSIDC extent increased +42k today. It is now only 38k below the 1986 (lowest maximum before 2017) annual maximum. Area is still safe: over +500k distance from the 1986 max.

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Re: Sea Ice Extent around Antarctica
« Reply #735 on: October 07, 2017, 05:14:15 PM »
NSIDC extent on 6th Oct measured a remarkable 17.999996M. First time that five nines appeared in the extent or area data, Arctic or Antarctic.

It still is 27k below 1986 annual maximum.

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Re: Sea Ice Extent around Antarctica
« Reply #736 on: October 09, 2017, 03:33:47 PM »
NSIDC extent went up +73k to 18.060M, highest value in 2017. Higher than the 1986 max.

So from an early maximum date, 2017 will now be among the latest ones. Next lowest maximum is held by 2002 at 18.116M (9-9-2002).

Area is still safely staying at the lowest maximum.

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Re: Sea Ice Extent around Antarctica
« Reply #737 on: October 13, 2017, 06:24:01 PM »
Antarctic sea ice extent (JAXA data) reached a maximum of 17.640 million km2 on 25th August. 7 days later it is 125,000 km2 less at 17.515 million km2. In this period the average gain is 250,000 km2.
However, there are often big ups and downs in September, so a surprise may be in store either way, especially given average date of maximum is more like around the 20th September. If 25th August ends up as the date of maximum (2016 was on 29th August) - good heavens.

So, like a fool I will prognosticate a maximum extent of less than 18 million km2.

The extent losses reversed themselves and have now reached a season high on October 9, 2017. See Wipneus graph below. Predicting ice is a dangerous bet sometimes!
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Re: Sea Ice Extent around Antarctica
« Reply #738 on: October 13, 2017, 07:13:55 PM »
According to NSIDC data, it seems like the seasonal maximum was reached at October 11 and possible also virtually tied by October 12. If October 12 is going to be a confirmed date by NSIDC it will be a tie of the absolutely latest date a seasonal maximum has occurred around Antarctica.

The other year this happened was 2002. If you compare 2002 with 2017 from the middle of May or so, you will see a remarkable similarity between these two years.

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Re: Sea Ice Extent around Antarctica
« Reply #739 on: October 13, 2017, 07:40:21 PM »
According to NSIDC data, it seems like the seasonal maximum was reached at October 11 and possible also virtually tied by October 12. If October 12 is going to be a confirmed date by NSIDC it will be a tie of the absolutely latest date a seasonal maximum has occurred around Antarctica.

The other year this happened was 2002. If you compare 2002 with 2017 from the middle of May or so, you will see a remarkable similarity between these two years.

this post has been deleted because it was wrong (badly researched and not verified as correctly pointed out by LMV below) :-[
« Last Edit: October 14, 2017, 12:06:56 AM by magnamentis »

Lord M Vader

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Re: Sea Ice Extent around Antarctica
« Reply #740 on: October 13, 2017, 10:44:00 PM »
Mag: I'm sorry, but where do you get the number 2 Mn from? From June 1 and onward the biggest difference is only 500K.

magnamentis

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Re: Sea Ice Extent around Antarctica
« Reply #741 on: October 14, 2017, 12:05:10 AM »
i'm not one who has to be sorry, shame on me, i mixed something up and looked in an entirely wrong graph, even had a feeling but was to lazy to go back and verify, double fail  :-[

you are and were totally right, embarrasing but it happend ;)

thanks for correcting, ill alter the post now

gerontocrat

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Re: Sea Ice Extent around Antarctica
« Reply #742 on: October 15, 2017, 02:47:43 PM »
JAXA DATA
Jaxa is having a day off but I show the graph below to illustrate the degree to which extent loss in the next month must exceed the average to match 2016.
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Pavel

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Re: Sea Ice Extent around Antarctica
« Reply #743 on: October 15, 2017, 11:50:02 PM »
Things are getting hot and almost 5°C anomaly forecasted

kiwichick16

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Re: Sea Ice Extent around Antarctica
« Reply #744 on: October 17, 2017, 10:28:26 PM »
looks like parts of the Ross Ice Sheet are close to + 20 degrees

Wipneus

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Re: Sea Ice Extent around Antarctica
« Reply #745 on: October 18, 2017, 03:37:47 PM »
Update of NSIDC NT extent and area graphs.

gerontocrat

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Re: Sea Ice Extent around Antarctica
« Reply #746 on: October 18, 2017, 04:20:16 PM »
Things are getting hot and almost 5°C anomaly forecasted
While SST anomalies are high on the Antarctic continent itself they are mostly zero to -ve offshore, i.e. where the sea ice is. This may be why sea ice extent loss is still moderate.
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miki

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Re: Sea Ice Extent around Antarctica
« Reply #747 on: October 18, 2017, 05:22:44 PM »
Things are getting hot and almost 5°C anomaly forecasted
While SST anomalies are high on the Antarctic continent itself they are mostly zero to -ve offshore, i.e. where the sea ice is. This may be why sea ice extent loss is still moderate.

Can that also be because ice is melting over there, causing the temperature to cool and the anomalies to zero?

gerontocrat

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Re: Sea Ice Extent around Antarctica
« Reply #748 on: October 21, 2017, 04:14:48 PM »
JAXA DATA
So far extent loss has been very slow - just 0.46 million km2 to 20th October, compared with 1.29 million km2 last year and the 10 year average of 0.84 million km2. As a result extent on 20th October is nearly 0.4 million km2 greater than on that date in 2016.
If extent loss fails to markedly accelerate soon, it is likely that 2017 extent will merge into the pack.
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gerontocrat

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Re: Sea Ice Extent around Antarctica
« Reply #749 on: October 24, 2017, 01:02:41 PM »
JAXA DATA

herewith table and graph re extent loss to date (23rd October). Very slow melt continues.
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