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ARS Home » Northeast Area » Beltsville, Maryland (BARC) » Beltsville Agricultural Research Center » Hydrology and Remote Sensing Laboratory » Research » Publications at this Location » Publication #340300
Title: Estimating and validating surface energy fluxes at field scale over a heterogeneous land surfaces based on two-source energy balance model (TSEB)

Author
item LI., Y. - Chinese Academy Of Sciences
item Kustas, William - Bill
item Anderson, Martha
item Huang, Carina

Submitted to: BARC Poster Day
Publication Type: Abstract Only
Publication Acceptance Date: 4/7/2017
Publication Date: 4/26/2017
Citation: Li., Y., Kustas, W.P., Anderson, M.C., Huang, C. 2017. Estimating and validating surface energy fluxes at field scale over a heterogeneous land surfaces based on two-source energy balance model (TSEB). BARC Poster Day. pg. 42

Interpretive Summary:

Technical Abstract: Accurate estimation of surface energy fluxes at field scale over large areas has the potential to improve agricultural water management in arid and semiarid watersheds. Remote sensing may be the only viable approach for mapping fluxes over heterogeneous landscapes. The Two-Source Energy Balance model (TSEB) has been successfully applied to estimate surface energy fluxes and evapotranspiration (ET) over a variety of land cover types under different climatic conditions. In this study, the performance of TSEB at field scale is evaluated in a heterogeneous desert-oasis zone in northwest of China with complex land cover types including maize, vegetable, orchard, natural deserts and wetlands. To achieve estimates of surface energy fluxes at field scale with high temporal resolution, the remotely sensed land reflectance and land surface temperature data with high spatiotemporal resolution (hereinafter referred to as ASTER-like data) were obtained by combining the Moderate Resolution Imaging Spectroradiometer (MODIS) and the Advanced Space-borne Thermal Emission Reflectance Radiometer (ASTER) spatiotemporal characteristics based on the Thermal Adaptive Reflectance Fusion Model (STARFM) in the desert-oasis zone from June to September, 2012. The surface fluxes at field scale were estimated by combining ASTER-like data and observed meteorological data for input to TSEB and were validated using in-situ flux observations from Eddy Covariance (EC) systems located in maize, vegetable, orchard, three desert sites and a wetland. The comparison between estimated and observed surface fluxes indicated that TSEB performs well for maize, vegetable, orchard and wetland sites with values of mean absolute percentage (MAP) ranging from 9 to 18%. However, TSEB tended to underestimate sensible heat flux (H) and overestimate latent heat flux (LE) or ET for desert sites covered by sparse vegetation where H is the dominant flux and LE or ET rates are low. The results of a sensitivity analysis showed that net radiation (Rn) and LE computed from TSEB are moderately influenced by remotely sensed leaf area index, canopy fraction, and land surface temperature for all land cover types studied. However, values of two coefficients used in the TSEB soil resistance formulation are shown to have a significant impact on estimated H and LE for the desert sites. Consequently, more detailed information about the soil roughness and plant distribution that affect the soil resistance coefficients is likely to improve estimates of H and LE from TSEB for desert sites.