Making use of a breadboard model of Microwave Scanning Radiometer (MSR) of Marine Observation Satellite (MOS)-1 and other instruments, field ex-periments to obtain physical properties of snow and radiometric characteristics were made for 3 consecutive winter seasons from 1982 to-1984.
Analyses of the data indicate the decrease of microwave brightness temperature (Tb) with increasing snow depth, however beyond the depth of the minimum Tb a reverse tendency, i.e. increase of Tb with increasing snow depth, is recognized in some cases although the value itself is small. It is proposed to call the phenomenon a brightening effect. It is found that an emission model of 3rd order polynomials in terms of parameters which are combinations of optical depth and albedo can satisfactorily explain the phenomenon.