Thoughts on the ocean, the environment, the universe and everything from nearly a mile high.

Panorama of The Grand Tetons From the top of Table Mountain, Wyoming © Alan Holyoak, 2011

Friday, February 24, 2012

Approaching Arctic Ocean Annual Sea Ice Maximum Extent For 2012

One of my favorite climate-related web sites is the This is the site of the National Snow and Ice Data Center, housed at the University of Colorado, Boulder.  This is a great place to check on the state of snow and ice around the globe: the Arctic, the Antarctic, Greenland, mountain glaciers, etc.

The NSIDC posts a near-real time map and graph showing the current sea ice extent and recent trend of sea ice compared with a baseline average of the years 1979 through 2000.

Anyway, it's late February 2012, and according to the baseline data, this is the time of year that we are approaching maximum sea ice extent for the year.  The NSIDC defines an area to be "covered" by sea ice if a location has at least 15% of its surface area covered by sea ice.

Here is the most recent map showing sea ice cover, compared to the 1979-2000 baseline average:

The orange line on the map shows the baseline average extent of sea ice cover from the years 1979-2000. The white area shows the reported current extent of at least 15% sea ice cover based on satellite data provided by  NSIDC scientists note that there is more ice than usual in the Bering Sea north of the Aleutian Islands - remember the challenge faced by residents of Nome, Alaska, earlier this winter when sea ice prevented shipping from reaching them?  At same time, just about everyplace else in the Arctic shows a lower sea ice extent than the historical baseline.  This is especially true in the Kara Sea and Arctic Ocean North of Scandinavia.

The figure below shows that we are fast approaching the annual sea ice maximum for 2012.  The maximum extent is usually reached sometime between mid-February and mid-March, so we are in the window.  Current Arctic sea ice extent (blue line) shows that the current sea ice extend is about 1.2 million square kilometers less than the historic baseline (dark gray line).  The current extent is also well below the + 2 standard deviation range (light gray zone) around the average baseline.  This means that yet again, the current sea ice extent is statistically significantly lower than the baseline.  And sea ice extent in the Arctic is comparable to the sea ice extent observed in 2006-2007 which produced the lowest summer sea ice extent on record.

Is this the record lowest extent for this date?  No.  The record for the lowest extent for this date goes to February 2011: last year - when we also saw the second lowest summer sea ice extent on record.

Does this mean that we will have a record low sea ice extent in Summer 2012?  No one knows.  The lowest sea ice extent is a product of not only a warming climate, but of prevailing short-term wind patterns and other weather conditions between now and then.  All we can really do is sit back and see what does happen.

So, until next time, keep an eye on the sky, the thermometer, and the ice.  Cheers!

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