 The Alexi model is a multi-sensor TIR approach to ET mapping, combining a two-source, soil-plus canopy, land-surface model with an atmospheric boundary layer model in time-differencing mode to routinely and robustly map daily fluxes at continental scales in 5-10 km resolution using thermal band imagery and insulation estimates from geostationary satellites. This model has potential for global applications by integrating data from multiple geostationary meteorological satellite systems, such as the U.S. Geostationary Operational Environmental Satellites, the European Meteosat Satellites, the Chinese Finyang 2B series, and the Japanese Geostationary Meteorological Satellites. This article was authored by M. C. Anderson, W. P. Custas, J. M. Norman, and others.