A bispectral method for the automatic determination of parameters for use in imaging satellite cloud retrievals

Abstract Two major problems in deriving cloud amounts and physical properties from satellite imagery are the selection of suitable surface-type discriminators, which may vary as a function of time and place, and the extraction of cloudiness on the subpixel scale. We present a method of retrieving suitable parameters for such discriminations on the local scale, based on the information contained in a bispectral (visible and 11 μm infrared) histogram. The application of these parameters to the retrieval of cloud information on both the pixel and subpixel scales is demonstrated.