Measuring Arctic clouds with the infrared cloud imager

A thermal infrared imaging system has been developed for studying the spatial and temporal statistics of clouds. The Infrared Cloud Imager (ICI) system acquires radiometrically calibrated images of downwelling atmospheric radiation that are used to identify and classify clouds according to their radiometric brightness. The ICI system has been deployed in the Arctic during the winter of 2000-2001at Poker Flat Research Range near Fairbanks, Alaska, and during February - May, 2002 at Barrow, Alaska. This paper describes the ICI system and its calibration, shows images of various clouds, and discusses ongoing research to develop automated algorithms for cloud classification.

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