ESTIMATING SOIL WETNESS USING SATELLITE DATA

Improved estimates of soil wetness were obtained using observations from both the NIMBUS-7 Scanning Multichannel Microwave Radiometer (SMMR) and the NOAA-7 Advanced Very High Resolution Radiometer (AVHRR). SMMR 6. 6 GHz frequency, horizontal polarization, brightness temperature (T//B//H) was first correlated with soil wetness, as computed using an Antecedent Precipitation Index (API) model, for a number of SMMR ground resolution areas involving a fairly wide range of vegetation densities. Linear regression results were used to develop a diagnostic model for soil wetness using SMMR and AVHRR data only. The model was found to be useful in describing four levels of soil wetness as compared to three levels when vegetation was not considered.