Passive and Active Microwave Studies of Wet Snowpack Properties: Results of March 4, 1981, Aircraft Mission

Microwave signatures have been found to be related to variations in snow conditions found on the earth's surface. Most of these observations have been obtained by passive microwave radiometry. In general, inverse relationships between microwave brightness temperature (T_B) and snow depth were observed for dry snowpacks. The results from truck-mounted scatterometers indicated that the backscattering cross sections from snowpacks increased with snow depths, also in dry snow conditions. The reported aircraft mission was the first trial in which simultaneous active and passive microwave measurements were made over a wet snowpack. The test site was located in the Colorado Rocky Mountains. The results from this experiment suggest that microwave techniques using both radiometers and scatterometers may be useful in determining snow water equivalent even when the snowpack is wet.