AIRBORNE SOIL-MOISTURE MEASUREMENTS FOR 1ST INTERNATIONAL SATELLITE LAND SURFACE CLIMATOLOGY PROGRAM FIELD EXPERIMENT

The airborne gamma radiation system of the National Weather Service (NWS) was used to measure soil moisture over a research area near Manhattan, Kansas, in 1987 and in 1989. The research was in support of the First International Satellite Land Surface Climatology Project (ISLSCP) Field Experiment (FIFE) by the National Aeronautics Space Administration. Twenty-four flight lines were established in the FIFE research area. A large number of ground soil moisture measurements were collected for calibration of the flight lines. The NWS standard operational method to obtain soil moisture estimates for flight lines that average 16 km in length, using three airborne measurements of gamma radiation fluxes, was adapted for use with the shorter FIFE flight lines. Examples of temporal and spatial variations of soil moisture for the FIFE research area are presented.