SEBAL FOR ESTIMATING HOURLY ET FLUXES OVER IRRIGATED AND DRYLAND COTTON DURING BEAREX08

摘要

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. The main objective of this paper was to evaluate the Surface Energy Balance for Land (SEBAL), an EB based ET estimation algorithm, using lysimeter data and three Landsat TM images covering a major portion of the Texas High Plains acquired during the Bushland Evapotranspiration and Agricultural Remote Sensing Experiment 2008 (BEAREX08). Performance of the SEBAL was evaluated by comparing estimated surface temperature, net radiation, soil heat flux, and hourly ET with measured data on four large lysimeters at the USDA-ARS Conservation and Production Research Laboratory, Bushland, Texas [35° 11' N, 102° 06' W; 1,170 m elevation MSL]. Crops on the lysimeter fields include irrigated and dryland cotton. Performance statistics indicated that SEBAL performed well estimating hourly ET rates for both irrigated and dryland cotton surfaces. Currently, more evaluation is being done to evaluate the SEBAL for other major summer crops grown in the Texas High Plains.