A simple surface temperature assimilation scheme for use in land surface models

This paper examines the utilization of surface temperature as a variable which can be assimilated in off‐line land surface hydrological models. The connection between the surface temperature and evapotranspiration is utilized in making adjustments to the model‐computed surface soil moisture. This adjustment is a function of the difference between the model‐computed and the observed surface temperature. Comparisons between the model‐computed and satellite‐observed surface temperatures have been carried out. The assimilation of surface temperature is carried out twice a day (corresponding to the A.M. and P.M. overpass of the NOAA 10) over the Red‐Arkansas basin in the southwestern United States (31°50′N‐36°N, 94°30′W‐104°30′W) for a period of 1 year (August 1987 to July 1988). The soil moisture estimates resulting from the assimilation of surface temperature have a closer agreement with the values derived from the special sensor microwave imager than those from simulations without surface temperature assimilation. Assimilation reduces the effect of errors in precipitation and/or shortwave radiation on simulated soil moistures.