Submitted to: IEEE Transactions on Geoscience and Remote Sensing
Publication Type: Proceedings
Publication Acceptance Date: March 26, 2008
Publication Date: July 6, 2008
Citation: Anderson, M.C., Kustas, W.P. 2008. Mapping evapotranspiration and drought at local to continental scales using thermal remote sensing. In: IEEE Transactions on Geoscience and Remote Sensing, July 6-11, 2008, Boston, Massachusetts. Abstract 3422.
Water lost to the atmosphere through evapotranspiration (ET) has the effect of cooling the Earth’s surface. Land-surface temperature (LST), as mapped using thermal-infrared (TIR) band data, is therefore a valuable remote indicator of both ET and the surface moisture status . In partially vegetated landscapes, depletion of water from the soil surface layer (0-5 cm) causes the soil component of the scene to heat rapidly. Moisture deficiencies in the root zone (down to 1-2 m depth) lead to stomatal closure, reduced transpiration, and elevated canopy temperatures, which can be effectively detected from space .
Proper interpretation of the TIR land-surface signal in terms of the underlying moisture status requires ancillary information about vegetation amount and local energy constraints (radiative and meteorological forcings) on the combined soil-plant-atmosphere system. These factors can be accounted for in a physical way within the context of a surface energy balance model. The Atmosphere-Land Exchange Inverse (ALEXI) modeling scheme described below is an example of one possible framework for synthesizing multi-scale, multi-platform thermal imagery into useful end-products for operational monitoring of drought and evaporative water loss.