GOES-12 imager decontamination

July 6th, 2007 |

GOES-12 3.9µm IR images

A GOES-12 imager “decontamination procedure” was performed on 02 July 2007, where certain internal optical components were heated in an attempt to drive off contaminants that had been accumulating for several years. One obvious problem associated with this internal contamination was a “rollover” of warm 3.9µm IR brightness temperatures, such that they were incorrectly displayed as very cold temperatures. This problem made it impossible to determine the hottest brightness temperatures associated with areas of intense fire activity (see recent examples from the Lake Tahoe, Lake Okeechobee, New Jersey, and Georgia fires).

Two sequences of daily GOES-12 3.9µm IR images show regions of sun glint off the Pacific coast of Mexico at 20:45 UTC (above), and also off the coast of Washington / British Columbia at 03:45 UTC (below). Prior to the decontamination procedure at 12:34 UTC on 02 July, portions of the sun glint that should have exhibited very warm IR brightness temperatures (black enhancement) were instead displayed as very cold areas (yellow enhancement); following the decontamination, the regions of daily sun glint were correctly displayed as having warm IR brightness temperatures, indicating that the procedure was successful.

GOES-12 3.9µm IR images

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