The potential of remotely sensed thermal infrared data to infer surface soil moisture and evaporation

Recently launched satellites provide high‐quality thermal infrared data suitable for estimating hydrologic parameters at the earth's surface. Analytical expressions are derived that relate mean evaporation rate and a quantity dependent on soil moisture (diurnal heat capacity) to surface temperature of bare soil areas. These expressions are corrected for micrometeorological effects through use of a numerical model which simulates the diurnal cycle of surface temperature under realistic air temperature, humidity, and wind speed conditions. Results illustrate the sensitivity of 24‐hour mean temperature to mean evaporation rate, and of the day‐night temperature range to near‐surface soil moisture. This suggests the potential of remotely sensed thermal data for assessing the surface moisture budget.