Estimating Actual Evapotranspiration using the SEBAL Model for the Atankwidi and Afram Catchments in Ghana

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International Journal of Applied Agricultural Research
Evapotranspiration (ET) monitoring has important implications on global and regional climate modelling. It is important for the hydrological cycle and assessment of environmental stress that affects ecosystems. Accurate measurement and estimation of ET is a basic input in computing water balance and to estimate water availability and requirements. Most methods for ET computation can only provide point estimates of ET for a specific location and fails to provide ET on a regional scale and makes it inadequate for proper water resource management. In this study, the Surface Energy Balance Algorithm for Land (SEBAL) model is used to estimate actual evapotranspiration (ETa) for different land use/cover types (closed woodlands, gallery forests, open woodlands, farmlands, water bodies, barelands, rocky areas and built-up areas) for the Atankwidi and Afram catchments in the Volta Basin of Ghana. It was found that the SEBAL model can successfully estimate and distinguish ETa among different land use/cover types in the two catchments. SEBAL estimates of ETa varied from 1.4 to 7.30 mm/day across the different land use/cover types. The range of CVs for ETa was 5−75% across the different land use/cover types for the two catchments. The results confirms SEBAL is an appropriate algorithm for estimating ETa using satellite images in catchments similar to that of the study areas, where few or no ground measurements are available.
This article is published in International Journal of Applied Agricultural Research
Evapotranspiration, Landsat, Land use, Remote sensing, SEBAL, Model
International Journal of Applied Agricultural Research, Volume 6 Number 2 (2011) pp. 177-193