Estimating bidirectional angles in NOAA AVHRR images

In studies concerning the surface bidirectional reflectance distribution fu nction (BRDF) and thermal-infrared multiangular emissions, Sun-sensor geome try must be known. This Letter provides a potential and simple method for N OAA Advanced Very High Resolution Radiometer (AVHRR) users to estimate the imaging configuration of each pixel in a geometrically corrected image. Our formulas were tested with example AVHRR data and their precision was shown to be comparatively high with a maximum error of either the satellite zeni th or azimuth angle less than 4 degrees. The standard deviation for the zen ith is 2.07 degrees and azimuth is 2.47 degrees.