A climatological study of evapotranspiration and moisture stress across the continental United States based on thermal remote sensing: 1. Model formulation

Due to the influence of evaporation on land‐surface temperature, thermal remote sensing data provide valuable information regarding the surface moisture status. The Atmosphere‐Land Exchange Inverse (ALEXI) model uses the morning surface temperature rise, as measured from a geostationary satellite platform, to deduce surface energy and water fluxes at 5–10 km resolution over the continental United States. Recent improvements to the ALEXI model are described. Like most thermal remote sensing models, ALEXI is constrained to work under clear‐sky conditions when the surface is visible to the satellite sensor, often leaving large gaps in the model output record. An algorithm for estimating fluxes during cloudy…