Mapping surface soil moisture with L-band radiometric measurements

Abstract

Radiometric measurements were made over two small watersheds with a four-beam pushbroom microwave radiometer aboard the NASA C-130 aircraft, during a dry-down period following a heavy rainfall in May and June 1987. The two watersheds were in the tall grass prairie region of Kansas. One of them was burned about 2 months prior to the measurements and the other was not burned for more than a year. Surface (0–5 cm) soil moisture data were collected close to the times of the aircraft measurements and correlated with the corresponding radiometric measurements. This established a relationship required for the mapping of surface soil moisture in these watersheds. It is shown that the radiometric sensitivity to soil moisture variation is higher in the burned watershed than in the unburned watershed. A comparison of the derived soil moisture contours also shows that the burned watershed loses surface soil moisture more rapidly than the unburned watershed.