Watts Up With That?
April 23, 2010

You gotta love it when the Earth gives back the love, especially today.*


Those who have been following NSIDC and JAXA sea ice plots have noted that this has been an extraordinary year so far, with Arctic sea ice hitting the “normal” line on some datasets. Today the Earth gave back more for us.*


As of today, JAXA shows that we have more ice than any time on this date for the past 8 years of Aqua satellite measurement for this AMSRE dataset. Yes, it isn’t much, but if this were September, and the sea ice minimum was down by this much compared to all other years, you can bet your sweet bippy we’d see it screamed in news headlines worldwide.*

Of course some will argue that it “doesn’t matter” in the context of trend, or that it’s just a “weather” blip. Let us remind our friends of such blips the next time a heat wave or a storm is cited as proof of global warming.*

What can be said about the short term trend in Arctic sea ice is that for the past two years, it has recovered from the historic low of 2007. It recovered in 2008, and more in 2009. If today’s Earth Day gift is any indication, it appears that it is on track now for a third year of recovery in 2010 as we’ve been saying at WUWT since fall of 2009.*

I’d show NSIDC’s current Arctic Sea Ice graph also, but their website was down earlier today, and the current sea ice graph is not updated. But Steve Goddard has made some comparison overlays that are interesting.*

He writes via email:*

NSIDC’s web site is down today, but I overlaid DMI on top of the NSIDC graph and it should have hit the mean line today. Same story for JAXA. *Images are below.

DMI uses 30% concentration, so their scale is lower than NSIDC and JAXA at 15%. *I shifted the DMI data upwards and stretched vertically to visually match the NISDC data. *

NSIDC versus DMI Arctic sea ice extent*

The second image is JAXA, DMI and NSIDC together. *JAXA also needed to be shifted vertically as they*apparently*use a different algorithm for*calculating*extent than NSIDC. * All three track each other fairly closely during the spring, *DMI diverges from the others during the fall freeze up *- probably because of the higher concentration requirements.*

NSIDC versus JAXA and DMI Arctic sea ice extent*

Blue is NSIDC. *Green is JAXA. *Black is DMI.* The thick black line is the NSIDC mean. The dashed line is the 2007 historic low.*

ADDED: Here is a wider view that shows that the three time series match closely over the interval of the NSIDC graph*


* NSIDC vs JAXA 4_22_2010 wideview*


Happy Earth Day everybody!*