Wednesday, March 02, 2011

Did February Sea Ice Extent Set a Record Low?

Joseph Romm writes that February 2011 Arctic Sea Ice Extent tied for a record low, but this isn't true according the Japanese JAXA satellite data.

According to JAXA, the average sea ice extent for Feb 2011 was in second place (according to my calculations):

avg for Feb 2006: 13.44 Mkm2
avg for Feb 2011: 13.52 Mkm2

Of course, sea ice extent isn't the best measure of Arctic melting -- that would be volume, which (as far as I know) is only calculated by PIOMASS (based, yes, partly on a model). That data isn't publicly available, so we don't know.

If extent was high I'm sure people like Romm would point out that it's really volume that matters. But since extent is low, they are OK with quoting it -- at least, according to someone.

Granted, it is strange that (as of March 1st) this year's sea ice extent is 2.6% below last year's value, what with the current phase of the North Atlantic Oscillation and all the northern hemisphere cold and all that.

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