Arctic Sea Ice Underestimated Due to Faulty Sensor

DMSP satellite Defense Meteorological Satellite Program solar panel outer space earth orbit planer sun photo

Surging over at DIGG right now, a story via Bloomberg with the hed Arctic Sea Ice Underestimated Due to Faulty Sensor. Put simply, there's more sea ice than we thought so: 1) green thinkers can breathe a sigh of relief that perhaps global warming feedback loops are not as bad as we thought, and 2) anthropogenic climate change deniers can raise a playground cry of "nah-nah-nanna," which loosely translates to "human-caused climate change is a ruse, punks."

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.

DIGG Dialogue in Paraphrase

POINT: Hey this discounts all climate science around global warming you crazy green idiots. Especially you, Gore.

COUNTERPOINT: This does not discount all climate science around global warming. The data is bad only for about six weeks time. And, oh: Gore be my eco hero, but I do hope he lays off the carbs (nota bene: we added that last part about the carbs)

Exeunt DIGG, Enter Meteorologist Anthony Watt

Eternally asking the punny question Watt's Up With That? -- and in the process winning a 2008 Best Science Blog Weblog Award -- weather-science-savvy Anthony Watt reminds his loyal readers that on February 16th he posted about a graph of arctic sea ice, which had been posted on the National Snow and Ice Data Center (NSID) sea ice news page, displaying an abrupt and puzzling downward jump in the blue line:

nsidc arctic sea ice extent data chart timeseries 021509 National Snow and Ice Data Center image

When the NSIDC announced they had discovered the reason why, that the sensor on the Defense Meteorological Satellite Program (DMSP) satellite they use had degraded and had failed to the point of being unusable, Watt reported the news (NSIDC: satellite sea ice sensor has "catastrophic failure" - data faulty for the last 45 or more days) that the sensor's slow decline for almost two months had caused a bias in the arctic sea ice data that underestimated the total sea ice by 500,000 square kilometers. Most interesting, however, is Watt's update of 2/19:

Walt Meier writes with a clarification: "One detail, though perhaps an important [one]. I realize that it is bit confusing, but it is just one channel of the sensor that has issues. And it isn't so much that it "failed", but that quality degraded to the point the sea ice algorithm - the process to convert the raw data into sea ice concentration/extent - failed on Monday.

Full article at Susty


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