SNOW DAYS DETERMINATION, USING PASSIVE MICROWAVE SATELLITE DATA

This paper reports the results of an initial investigation of the potential for remote sensing application with special reference to passive microwave satellite imagery. It is based on SSM/I data. The study area is of the whole of Iran, with one or two satellite passes being used per day. For the purpose of identifying snow from variable surface conditions, the snow maps presented in this study were generated using the Grody&Basist algorithm which is based on separating scatterers from emitters in the 19, 22, 37 and 85.5 GHz frequencies of the passive microwave region of the electromagnetic spectrum. Comparisons with surface observations from 136 synoptic stations obtained from the Iranian Meteorological Organisation are also provided. Conclusions are drawn as to the potential of combined satellite/surface methods for monitoring and understanding longer-term temporal variations in snow cover over Iran