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United States Department of Agriculture

Agricultural Research Service

Research Project: Leveraging Remote Sensing, Land Surface Modeling and Ground-based Observations ... Variables within Heterogeneous Agricultural Landscapes

Location: Hydrology and Remote Sensing Laboratory

Title: A thermal remote sensing modeling system for estimating evapotranspiration ovee complex landscapes

Authors
item Kustas, William
item Anderson, Martha
item Hain, Christopher -
item Gao, Feng
item Mecikalski, J -

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: June 20, 2013
Publication Date: N/A

Technical Abstract: Land surface temperature (LST) from thermal remote sensing is a surface boundary condition that is strongly linked to the partitioning of the available energy between latent (evapotranspiration) and sensible heat flux. Many of the approaches require an accurate LST and air temperature observation because the heat fluxes are related to the surface-air temperature differences. There is also difficulty estimating appropriate exchange coefficients for soil/substrate and vegetation temperatures influencing the LST observation and associated aerodynamic temperature. Related to this in irrigated agriculture is the need to partition water use from the crop (transpiration) from water loss from the soil/substrate in the inter-rows (evaporation). A two-source energy balance (TSEB) modeling scheme that estimates transpiration and soil/substrate evaporation using a time differencing in LST observations coupled to an atmospheric boundary layer growth model has been developed to adequately address the major impediments to the application of LST in estimating evapotranspiration over irrigated regions. The modeling system, Atmospheric Land EXchange Inverse (ALEXI), using geostationary LST observations and the disaggregation methodology (DisALEXI) together with data fusion techniques allow the modeling scheme to be applied at the field scale. The TSEB/ALEXI/DisALEXI modeling system is currently providing field to regional scale evapotranspiration estimates over U.S. agricultural regions, and plans are to develop a similar product for applications in other agricultural regions worldwide.

Last Modified: 10/22/2014
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