 Thermal infrared, TIR, remote sensing of land surface temperature, LST, provides valuable information about subsurface moisture status required for estimating evapotranspiration, ET, and detecting drought. While empirical indices measuring anomalies in LST and vegetation amount have demonstrated utility, they may provide ambiguous results when other factors are affecting plant functioning. A more physically based interpretation of LST and NDVI can be obtained with a surface energy balance model driven by TIR remote sensing. The Atmosphere Land Exchange Inverse, ALEXI, model is a multi-sensor TIR approach to ET mapping, coupling a two-source land surface model with an atmospheric boundary layer model in time differencing mode to map daily fluxes at continental scales in 5 to 10 kilometers resolution using thermal band imagery and insulation estimates from geostationary satellites. The ALEXI slash DysALEXI model has potential for global applications by integrating data from multiple geostationary meteorological satellite systems. Work is underway to evaluate multi-scale ALEXI implementations over various continents with geostationary satellite coverage. This article was authored by M. C. Anderson, W. P. Custas, J. M. Norman, and others.