Soil moisture estimation using time-series radar measurements of bare and vegetated fields in Washita ´92

During June, 1992 NASA, USDA, and Princeton University conducted a hydrology field experiment in the Little Washita River watershed near Chickasha, Oklahoma with a goal of characterizing the spatial and temporal variability of soil moisture using microwave sensors. As part of this experiment, several time series of radar images obtained by NASA/JPL´s airborne AIRSAR system over agricultural and pasture test sites were analyzed for their utility to soil moisture estimation. Two existing microwave backscatter models using copolarization ratios which were originally developed for base soils were examined in terms of their performance in the Washita ´92 bare fields and their potential role in a radar-based approach to determining soil moisture through vegetation canopies