Estimating surface soil moisture from SIR-C measurements over the Little Washita watershed

For more than two decades radar backscattering signals at a frequency range of 1-10 GHz have been demonstrated by a number of investigators to depend on surface soil moisture. Most of these past studies were limited to the forward problem in that the measured backscatter was directly correlated to the ground-measured soil moisture. Attempts to invert the experimentally measured radar backscattering signals to soil moisture values occurred only recently. The authors examined three out of these four attempts with respect to the SIR-C observations over a test site some 60 km southwest of Oklahoma City, Oklahoma. The results showed some promise, but also suggested the need of a close scrutiny of these inversion algorithms.