Mapping evapotranspiration at multiple scales using multi-sensor data fusion

Thermal-infrared remote sensing of land surface temperature (LST) provides valuable information for quantifying root-zone water availability, evapotranspiration (ET) and crop condition. This paper describes a multi-scale LST-based energy balance model built using a Two-Source Energy Balance (TSEB) algorithm, which solves for the soil/substrate and canopy temperatures and flux partitioning. A regional modeling system applies the TSEB to time-differential LST measurements from geostationary satellites, providing coarse ET estimates which can be downscaled to finer spatial resolutions using data from polar orbiting satellites. This modeling system, along with strategies for fusing information from multiple satellite platforms and wavebands, has been used to generate ET maps from field to global scales. We describe applications for high spatiotemporal resolution ET retrievals in assessing impacts of human activities and climate change on water resources and agricultural production.