Evaluation of Five Surface Energy Balance Approaches for Mapping ET Using Landsat TM Data Acquired During BEAREX08.

Numerous energy balance (EB) algorithms have been developed to make use of remote sensing data for mapping evapotranspiration (ET) on a regional basis. Adopting any or combination of these models for an operational ET remote sensing program requires thorough evaluation. In this study, we evaluated and compared five EB-based models for mapping ET using Landsat TM data in the semiarid Southern High Plains. Models evaluated include SEBAL, METRIC, TSM, SEBS, and SSEB. Data for model evaluation was collected during two large ET remote sensing experiments “Bushland Evapotranspiration and Agricultural Remote Sensing Experiment” conducted during 2007 and 2008 summer cropping season. Performance of the models was evaluated by comparing estimated hourly ET with measured data from four large monolithic lysimeters at the USDA-ARS Conservation and Production Research Laboratory, Bushland, Texas. Crops on the lysimeters include cotton, forage corn and forage sorghum managed under irrigated conditions and cotton and grain sorghum managed under dryland conditions. Strengths and weaknesses of the ET models were identified and discussed.