Snow cover identification through cirrus‐cloudy atmospheres using daytime AVHRR imagery

A technique has been developed for enhanced snow identification in cloud‐free and cirrus‐cloudy atmospheres using daytime AVHRR imagery. The procedure is based upon the strong contrast between snow and thin cirrus present in daytime 3.7 µm [albedo] data, which have been corrected for thermal emissions. Snow is identified by a strong yellow‐hue in a false‐color composite image constructed by assigning the 0.6 µm AVHRR channel to the red and green guns of a CRT and the albedo component of 3.7 µm channel to the blue gun. Surprisingly, snow becomes clearly discernible even in regions that appear to be obscured with thin cirrus clouds. This powerful image processing technique for mapping snow in cloud‐free and cirrus‐cloudy atmospheres may prove useful for a variety of applications, especially those associated with hydrological studies in regions that are frequently cloudy.