[Vision2020] NSIDC 9-15-2011: Arctic sea ice at minimum extent: 2011 Close 2nd Lowest

Ted Moffett starbliss at gmail.com
Sat Sep 17 16:41:57 PDT 2011

September 15, 2011 Arctic sea ice at minimum extent

Arctic sea ice appears to have reached its lowest extent for the year. The
minimum ice extent was the second lowest in the satellite record, after
2007, and continues the decadal trend of rapidly decreasing summer sea ice.
*Please note that this is a preliminary announcement. Changing winds could
still push ice flows together, reducing ice extent further. NSIDC scientists
will release a full analysis of the melt season in early October, once
monthly data are available for September.*
*Overview of conditions*

On September 9, 2011 sea ice extent dropped to 4.33 million square
kilometers (1.67 million square miles). This appears to have been the lowest
extent of the year, and may mark the point when sea ice begins its
cold-season cycle of growth. However, a shift in wind patterns or late
season melt could still push the ice extent lower.
This year's minimum was 160,000 square kilometers (61,800 square miles)
above the 2007 record minimum extent, and 2.38 million square kilometers
(919,000 square miles) below the 1979 to 2000 average minimum. Note that our
estimated uncertainty for extent is plus or minus 50,000 square kilometers
(about 20,000 square miles). The minimum ice extent this year is very close
to 2007, and indeed some other research groups place 2011 as the lowest on
record. At this point, using our processing and sensor series, the 2011
minimum is a close second.

*Conditions in context*
*The last five years (2007 to 2011) have been the five lowest extents in the
continuous satellite record, which extends back to 1979. While the record
low year of 2007 was marked by a combination of weather conditions that
favored ice loss (including clearer skies, favorable wind patterns, and warm
temperatures), this year has shown more typical weather patterns but
continued warmth over the Arctic. This supports the idea that the Arctic sea
ice cover is continuing to thin. Models and remote sensing data also
indicate this is the case. A large area of low concentration ice in the East
Siberian Sea, visible in NASA Moderate Resolution Imaging Spectroradiometer
(MODIS) <http://rapidfire.sci.gsfc.nasa.gov/subsets/?mosaic=Arctic> imagery,
suggests that the ice cover this year is particularly thin and dispersed
this year.
Vision2020 Post: Ted Moffett
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