Libertarian Vegan

The above graph, courtesy of the National Snow and Data Center shows “Daily total Arctic sea ice extent between 1 December 2008 and 12 February 2009 for Special Sensor Microwave/Imager SSM/I compared to the similar NASA Earth Observing System Advanced Microwave Scanning Radiometer (EOS AMSR-E) sensor.” What that means is that reports we have received about Arctic sea ice during that period underestimated the amount of ice by 193,000 square miles, roughly the size of California.

The mistake was caused by a glitch in satellite sensors that scientists refer to as “sensor drift.”  According to the NSIDC, “Sensor drift, although infrequent, does occasionally occur and it is one of the things that we account for during quality- control measures prior to archiving the data.  Although we believe that data prior to early January are reliable, we will conduct a full quality check.’’

The Center normally uses Department of Defense (the blue line in the above graph) satellites for their data, rather than more reliable NASA ones (the red lines above) because the DOD’s have a longer period of historical data, allowing for more long term studies.

Sea ice is used as a measure of how temperture changes affect the Earth, and is one of the cornerstones of the global warming movement.  Last August, data from the NSIDC actually showed a dramatic increase of 434,000 square miles, which is more than twice the size of Germany.

Compared to the data from August 2007, the Artic ice actually grew about 13%, despite the dire predictions. Sorry Al.

Sources: Bloomberg - Arctic Sea Ice Underestimated for weeks due to Faulty Sensor February 20, 2009

DailyTech - Arctic sees massive gain in ice coverage September 3, 2008

Trackback URI | Comments RSS