HR: 14:40h
AN: H43H-05    [Abstracts]
TI: Sensitivity Analysis on Remote Sensing Evapotranspiration Algorithm of Surface Energy Balance for Land
AU: Wang, J
EM: jwang@nmsu.edu
AF: Agro & Hort, NMSU, MSC3Q, BOX30003,Agro & Hort, NMSU, Las Cruces, NM 88003 United States
AU: * Samms, T
EM: tsammis@nmsu.edu
AF: Agro & Hort, NMSU, MSC3Q, BOX30003,Agro & Hort, NMSU, Las Cruces, NM 88003 United States
AU: Meier, C
EM: webmaster@weather.nmsu.edu
AF: Agro & Hort, NMSU, MSC3Q, BOX30003,Agro & Hort, NMSU, Las Cruces, NM 88003 United States
AU: Simmons, L
EM: luke@weather.nmsu.edu
AF: Agro & Hort, NMSU, MSC3Q, BOX30003,Agro & Hort, NMSU, Las Cruces, NM 88003 United States
AU: Miller, D
EM: dmiller@canr.uconn.edu
AF: Agro & Hort, NMSU, MSC3Q, BOX30003,Agro & Hort, NMSU, Las Cruces, NM 88003 United States
AU: Bathke, D
EM: djbathke@nmsu.edu
AF: Agro & Hort, NMSU, MSC3Q, BOX30003,Agro & Hort, NMSU, Las Cruces, NM 88003 United States
AB: Spatial evapotranspiration (ET) is usually estimated by Surface Energy Balance Algorithm for Land. The average accuracy of the algorithm is 85% on daily basis and 95% on seasonable basis. However, the accuracy of the algorithm varies from 67% to 95% on instantaneous ET estimates and, as reported in 18 studies, 70% to 98% on 1 to 10-day ET estimates. There is a need to understand the sensitivity of the ET calculation with respect to the algorithm variables and equations. With an increased understanding, information can be developed to improve the algorithm, and to better identify the key variables and equations. A Modified Surface Energy Balance Algorithm for Land (MSEBAL) was developed and validated with data from a pecan orchard and an alfalfa field. The MSEBAL uses ground reflectance and temperature data from ASTER sensors along with humidity, wind speed, and solar radiation data from a local weather station. MSEBAL outputs hourly and daily ET with 90 m by 90 m resolution. A sensitivity analysis was conducted for MSEBAL on ET calculation. In order to observe the sensitivity of the calculation to a particular variable, the value of that variable was changed while holding the magnitudes of the other variables. The key variables and equations to which the ET calculation most sensitive were determined in this study.
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