How About Accuracy AND Consistency?

Did you know that when it comes to monitoring the polar ice caps that being accurate at any given moment is secondary to being consistent in your data collection methods over long periods?

That's the excuse used by the National Snow & Ice Data Center (NSIDC) for the faulty satellite data that has for several weeks now under-reported a California-sized amount of Arctic sea ice.

Feb. 20 (Bloomberg) -- A glitch in satellite sensors caused scientists to underestimate the extent of Arctic sea ice by 500,000 square kilometers (193,000 square miles), a California- size area, the U.S. National Snow and Ice Data Center said.

The error, due to a problem called “sensor drift,” began in early January and caused a slowly growing underestimation of sea ice extent until mid-February. That’s when “puzzled readers” alerted the NSIDC about data showing ice-covered areas as stretches of open ocean, the Boulder, Colorado-based group said on its Web site. [SNIP]

The extent of Arctic sea ice is seen as a key measure of how rising temperatures are affecting the Earth. [SNIP]

The NSIDC uses Department of Defense satellites to obtain its Arctic sea ice data rather than more accurate National Aeronautics and Space Administration equipment. That’s because the defense satellites have a longer period of historical data, enabling scientists to draw conclusions about long-term ice melt, the center said.

“There is a balance between being as accurate as possible at any given moment and being as consistent as possible through long time-periods,” NSIDC said.

NSIDC is one of the organizations that is still contending that ice levels are retreating, even though actual visual examinations are showing that sea ice has returned to levels not seen in several decades.

You don't suppose there's an agenda involved?

I'd have a great deal more confidence in NSIDC is they'd be a little more concerned about "sensor drift" and accurate readings at any specific given time.