Applications of passive microwave observations of surface soil moisture

In large scale held experiments over the past 10 years, long wavelength microwave radiometers were used to map surface soil moisture with considerable success. These experiments, which include FIFE (87 & 89), Monsoon '90, Washita 92 and 94, and HAPEX-Sahel, covered a wide range of climatic regimes. The results from these experiments show that the microwave emission at the 21 cm wavelength is a strong function of surface (0-5 cm) soil moisture and thus can be used to map spatial and temporal variations of the moisture content of this soil layer. The salient results from these experiments will be presented and compared. The use of the surface soil moisture data to determine geophysical parameters such as evaporative fraction, soil evaporation and soil hydraulic properties will be discussed and results presented. (C) 1998 Elsevier Science B.V. All rights reserved.