Snow water equivalent estimation by microwave radiometry

Abstract

Snow water equivalent (SWE) is one of the most important parameters for accurate prediction of snowmelt runoff. Conventionally, SWE is monitored using observations made at widely scattered points in or around specific watersheds. Remote sensors, which provide data with better spatial and temporal coverage, can be used to improve the SWE estimates. Microwave radiation, which can penetrate through a snowpack, may be used to infer the SWE. Calculations made from a microscopic scattering model are used to simulate the effect of varying SWE on the microwave brightness temperature. Data obtained from truck mounted, airborne and spaceborne systems from various tests sites have been studied. The simulated SWE compares favorably with the measured SWE for dry snowpacks. In addition, whether or not the underlying soil is frozen or thawed may be discriminated using the polarization information obtained by spaceborne sensors.