Document Type : Research Paper
Authors
National Salinity Research Center
Abstract
Use of Surface Energy Balance Algorithm for Land (SEBAL) and satellite imagery is a relatively new procedure for estimation of actual ET at different scales e.g. farm, catchments and basin levels. This method is based on computation of latent heat flux as the residual of energy budget equation (LE=Rn-G-H) and is now used widely around the world, including Iran, for computation of evapotranspiration under standard and non-standard conditions. Azadegan plain is one of the plains that is now faced with waterlogging and salinity problems due to its special topographic, climatic, and hydrologic situations and also due to improper management of its water and soil resources. The main objective of this study was to use the SEBAL to calculate actual ET (ETa) of winter wheat in 2007-2008 cropping season. For this purpose, a seasonal time series of 19 MODIS satellite images and also ancillary climatic data were acquired and used. Finally, time series of daily ETa maps and also a seasonal ETa map were generated and analyzed. Since the crops of the region are under salinity stress, the calculated ETa is an explanatory of crop water requirement under non-standard conditions. The results could help in advising a proper water management plan and also strategies for control and management of salinity and water logging in the region.
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