Theoretical and Experimental Studies of Microwave Emission Signatures of Snow

The brightness temperature of snow in Finland has been studied theoretically and experimentally at 5,12, and 37 GHz for satellite remote sensing applications. A snow model consisting of ice spheres covered by a water shell has been used in theoretical calculations taking into account scattering and absorption. The brightness temperature of a natural snow field on the bare ground and on the ground covered with aluminum sheets has been measured from a tower. The experimental brightness temperatures are compared with calculated ones and show a reasonably good agreement. Experimental results also show that relatively small changes in the snow conditions cause large changes in the brightness temperature. Possible methods for using satellite observations in the remote sensing of snow are suggested.