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Gas Glo

Revision makes it third highest one day fall in September:

Record falls in (or partly in or later than) September are:

1 day falls
15/09/2003 -96719
07/09/2008 -68437
07/09/2010 -66093
18/09/2004 -61563
03/09/2010 -58594

2 day avgs
01/09/2008 -54453
15/09/2003 -65234.5
04/09/2010 -56015.5
07/09/2010 -54453
01/09/2003 -53906.5
05/09/2008 -50703

3day avgs
07/09/2010 -65234.5
02/09/2008 -55260.33333
07/09/2010 55000
16/09/2003 -46146
06/09/2007 -44323
07/09/2008 -43020.66667

4day avgs
07/09/2010 -54609.25
01/09/2008 -51367.25
07/09/2008 -46796.75
06/09/2007 -42500
01/09/2002 -36914

5day avgs
07/09/2010 -55406.2
02/09/2008 -47781.2
08/09/2010 -42312.4
01/09/2002 -37062.6
07/09/2007 -36062.4
04/09/2003 -35437.6

6day avg
07/09/2010 -50859.33333
01/09/2008 -44218.83333
01/09/2003 -38203.16667
09/09/2008 -36536.33333
05/09/2003 -34922

7 day avg
01/09/2008 -49665.28571
07/09/2010 -43169.57143
01/09/2002 -41785.71429
08/09/2008 -34598.14286
01/09/2007 -33816.85714

2010 features pretty prominently in all of those so I think I can drop my note about cherrypicking the averaging period. The falls in September this year do look significant.

Neven

Toby, I'm trying to put out a new SIE update later today, but it has something to do with the weather forecast.

Gas Glo

Apologies 2 day average ending 1 September 2008 is the record at -66172 not (-54453 as posted above).

Kevin McKinney

Thanks for the correction, Gas Glo, I noticed--shall I call it an anomaly?--but got hold of the wrong end of the stick and suspected a typo in the 2003 number. . .

Kevin McKinney

The question of compaction vs. melt right now is an interesting one. Looking at the CT concentration map, "Eyeball Mark I" reported compaction going on. . . then I read Lodger's analysis of the CAPIE numbers, which also seems fairly convincing. Of course, as physical processes you can (and, I'm sure, often enough do) have both happening simultaneously. Quite likely we do right now.

As mentioned on another thread (IIRC), the IJIS-JAXA and NSIDC methodologies differ in terms of spatial resolution--also in terms of temporal resolution, right? (5-day versus 2 day moving averages?) (Although if it were 5 days vs. 2, I'd expect extent to be decreasing faster now, and the CAPIE number to be rising, not dropping.)

Ah well, I'm clearly spinning my wheels here. Still, it's an interesting discrepancy.

Neven

Kevin, I've been thinking about that too. How can CAPIE remain so low, when 'tis the season to be compacted? I think we've got convergence on the Pacific side (and a bit melt because the waters are relatively warm over there), and divergence on the Atlantic side, with some more melting. It's weird. This year looks weird.

Steve Bloom

You're on thin ice with that speculation, Neven. :)

Steve Bloom

L. Hamilton, my impression from various scientist comments I've seen over the past few years is that it was anticipated that the area to the north of Nares Strait and in and north of the archipelago would constitute a sort of sea ice refugium that would persist for some years after the central basin starts melting out. Based on the behavior of this year's ice, I think it's clear that the archipelago will serve in no such role. Without that, the remaining area above Nares Strait starts to look like the sort of thing winds could blow to the east and so to melting in the Fram Strait.

Steve Bloom

Joe Romm has an excellent post describing and placing in context new results on the history of Arctic sea ice.

Steve Bloom

Below is a link to a public copy of the "History of sea ice in the Arctic" paper discussed by Romm. It's a review and synthesis paper featuring many of the big names in the field.

http://www.cgd.ucar.edu/oce/mholland/papers/Polyak_2010_historyofseaiceArctic.pdf

Christoffer Ladstein

Before I will find my way to the sheets (past 11 PM Norwegian time), I am confident of wakening up to a SIA far below the 5 mill. "milestone". 4.975.000 will be a close estimate.
These are exciting days!
Not only the Arctic is melting away, also the Norwegian glaciers are struggling hard, they've never measured such low quantity of summersnow as this year.
So no matter how fast or not the Ice covering Greenland, Canada, Norway, Iceland is vaporizing, the sealevel is bound to rise!

Steve Bloom

Hmm, Christoffer, it seems like it was only yesterday when the growth of the Norwegian maritime glaciers was being touted in the denialosphere as evidence of cooling.

I have a question for the more informed: I don't frequently look at the CT graphics, but when I did today for the first time in a while it appeared that we're only about 120K above the 2007 record low area. Can that be right? I had assumed several weeks back that all of the metric records were far out of reach for 2010. This must have been discussed somewhere here, so please excuse me for missing it.

Artful Dodger

Steve, I'll have a go at your question. This table compares minimum September CT Sea Ice Area to the Sep 6, 2010 minimum of 3.1098619 M km^2:

Year DD minSIA 2010-Year
---- -- ------ ---------
2006 23 4.0169 -907,057
2007 07 2.9194 +190,423
2008 08 3.0036 +106,306
2009 09 3.4246 -314,736
You can see that the 2007 and 2008 minimums are still below the latest SIA for 2010.

Steve Bloom

Thanks, Dodger. So ~190K as of the 6th, but does that go with the graphic I looked at today? IOW is it showing a couple more days of loss to put things closer to my eyeball result of ~120K? In any case it's good to know I wasn't fundamentally out in left field. Also, where are those numbers kept on the CT site? I found the archive of graphics easily enough, but no numbers (at least not in an easily accessible form). Also, do we know for a fact that the graphics and numbers are updated at the same time? I was eyeballing this graphic, BTW: http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/seaice.area.arctic.png

Artful Dodger

Steve: The CT Sea Ice Table is here. Note that the Date is expressed as "Year.Frac". If you're not familiar with that usage, read about the YEARFRAC function in the help for your Spreadsheet.

Basically, drop the Integer part of the number, and multiply the fractional part by 365 to get the Day of the year (similar to MODIS dates). Be warned that the Date produced is for Midnight at the end of that day (since the origin CT uses for YEARFRAC is Jan 1, 00:00 hrs). So just check for Date alignment errors when comparing CT data with other sources.

me.yahoo.com/a/nSjChi4X3vr8X3DRw93GkY1.cerja.8nvWk-

Steve, the data is here: http://arctic.atmos.uiuc.edu/cryosphere/timeseries.anom.1979-2008

Steve Bloom

Great, thanks to both of you. So since I don't think I could be off as much as ~70K in eyeballing the graphic, either the graphing software's not very precise or the graph includes another couple of days of data. Since the difference is about right for those two days, it's hard to tell which. In any case, if the 2010 ice performs from the 6th to 13th as it did from the 30th to the 6th, we have a new winner. Likely it won't do quite that well (I suppose I should be saying poorly rather than well), but with another couple of weeks available for further reductions I'm betting on it (figuratively speaking).

Evilreductionist.blogspot.com

Christopher Ladstein,

Almost bang on. :)

4,977,344

We could come close to 2008 - if we lose the average for the last 5 years, we lose another 100,000 or so. But if we push the limits and the melt season lasts until late September, 200,000 plus is possible.

ThomasE

Another site with stunning graphs depicting the last 2000 years of temp history in the arctic. The hockey stick shape emerges stronger than ever.

http://climateprogress.org/2009/09/03/science-study-hockey-stick-human-caused-arctic-warming-overtakes-natural-cooling/

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