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Sudan Journal of Agricultural Research

Estimating actual evapotranspiration using surface energy balance algorithm for land (SEBAL) for Gezira scheme. Part I: Determination and calculation of intermediate parameters

Bashir M.A., T. Hata, A. Tada , H. Tanakamaru, and Abdelhadi A. W.

Abstract:

Energy fluxes equilibrium at the land surface is required for many disciplines, such as hydrology, meteorology and agronomy. Surface Energy Balance Algorithm for Land (SEBAL) is a multi-step model that uses spectral satellite measurements and minimal meteorological data. The algorithm aims to solve the surface energy balance for each pixel of the image, the energy required to evaporate water is estimated as the rest term in the surface energy balance at the earth’s surface. In this study different scenes from landsat7 enhanced thematic mapper plus (ETM+) were used to derive the most crucial intermediate parameters such as normalized difference vegetation index (NDVI), radiometric surface temperature, surface emissivity, albedo, aerodynamic resistance, surface-air temperature gradient and evaporative fraction from which the different surface energy fluxes were estimated. The algorithm has proved to provide the energy fluxes at the surface of soil and vegetation at reasonable spatial and temporal scales.


 

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Sudan Journal of Agricultural Research Vol. 8 (2007) PP. 65-76