Estimation of Evapotranspiration and Biomass Production Using Remote Sensing Techniques in Lake Ziway Catchment
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Date
2007-12-04
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Addis Ababa University
Abstract
Estimation of actual evapotranspiration and biomass production require accurate real circumstances, i.e. for heterogeneous terrain composed of various agroecosystems under erratic rainfall patterns, sparse canopies, and imperfectly managed drainage systems. Hence, it is necessary to evaluate whether the current conventional methods can estimate the actual evapotranspiration and biomass production frequently with accurate measurement from limited meteorological data. This study shows surface energy balance algorithm (SEBAL) method used to compute actual evapotranspiration and biomass production in Central Main Ethiopian Rift System and adjacent highlands of Lake Ziway catchment.
Actual evapotranspiration and biomass production maps have been generated for the year 2004 and 2005 respectively. The results of this study show that daily actual evapotranspiration lies in the range between 0.7 and 8 mm/day, in which the spatial variability of daily actual evapotranspiration were demonstrated. Monthly actual evapotranspiration was ranging from 27 to 250 mm/month. This also suggests that the spatiotemporal variability of monthly actual evapotranspiration through out the seasons occurred. Moreover, in SEBAL analyses dry biomass production over traditionally cultivated farm lands was 150 Kg/ha on average whereas dry biomass production increases during the late crop growing stage. Therefore, It is concluded that the remotely sensing energy balance model, such as SEBAL can be used to retrieve important crop parameters of actual evapotranspiration and biomass production.
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Estimation, Evapotranspiration, Biomass Production, Using Remote, Sensing Techniques, Lake Ziway Catchment