Soil moisture content and the air-surface exchange rate of water vapor are crucial variables in studies of hydrology, meteorology, and plant sciences. A model framework for parameterizing subgrid-scale surface fluxes (PASS) has been developed to use satellite data, models, and limited surface observations to infer these variables on a seasonal basis with moderate spatial resolution over large terrestrial areas. The Walnut River Watershed, which covers an area of approximately 5000 square kilometers east of Wichita, Kansas, was used as a testbed to evaluate some preliminary applications of the PASS approach to infer soil moisture content. Measurements of a wide range of hydrological and boundary layer parameters were made during April and May 1997 by the Cooperative Atmosphere-Surface Exchange Study (CASES) consortium in collaboration with the Argonne Boundary Layer Experiments effort and the Atmospheric Radiation Measurement program. One of the major components of the 1997 CASES field campaign was observation and subsequent modeling of the effects of soil moisture content on the diurnal cycle of the planetary boundary layer. Variations in precipitation, surface vegetation, and thus soil moisture content were significant across the Watershed, but the soil moisture content was measured in situ at only 8-10 stations. To obtain more complete spatial coverage, the PASS model was applied. Data from Advanced Very High Resolution Radiometers on the NOAA-12 and NOAA-14 satellites were collected and adjusted for atmospheric effects with LOWTRAN7 and data from radiosondes. The input variables for the PASS model consisted of the resulting values of normalized difference vegetation index (NDVI) and surface brightness temperature, together with local observations of downwelling solar irradiance, air temperature, relative humidity, and wind speed. A measure of extractable soil moisture in the plant root zone was one of the quantities estimated with the PASS model. Comparisons with the in situ estimates indicated that the overall trends of soil moisture content were simulated fairly well but that surface vegetative conditions need to be described more precisely in the model than with the first-run practice of assuming that the entire area is covered with grasslands with a canopy height of 40 cm. Values of NDVI, surface brightness temperatures, land use maps, and local observations can be employed to improve assumptions used in the PASS model for vegetative conditions and various parameterizations