Browsing by Author "Salifu, Tayari"

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    DISTINGUISHING LAND USE TYPES USING SURFACE ALBEDO AND NORMALIZED DIFFERENCE VEGETATION INDEX DERIVED FROM THE SEBAL MODEL FOR THE ATANKWIDI AND AFRAM SUBCATCHMENTS IN GHANA
    (ARPN Journal of Engineering and Applied Sciences, 2012-01) Salifu, Tayari; Agyare, W. A.
    Distinguishing land use types is mostly done through field surveys which does not easily capture the spatial changes in the land use/cover types. In this study, the Surface Energy Balance Algorithm for Land (SEBAL) model was used to estimate surface albedo and NDVI, for different land use/cover types for two sub-catchments (i.e., Atankwidi and Afram) in the Volta Basin of Ghana. The mean coefficient of variation (CV) for individual land use/cover types compared to the mean CV for a given site was then used to distinguish among the land use/cover types. It was found that these parameters derived from the SEBAL model can be used to distinguish among different land use/cover types in the two subcatchments. SEBAL estimates for surface albedo and NDVI across the different land use/cover types varied from 0.05 to 0.22 and -0.41 to 0.38, respectively. The range of CVs for surface albedo and NDVI, were 5-22% and 7-175%, respectively across the different land use/cover types for the two catchments. The results of this study demonstrate that SEBAL’s derived surface albedo and NDVI can be used to distinguish land use/cover types in catchments similar to those of the study areas with few ground measurements.
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    Estimating Actual Evapotranspiration using the SEBAL Model for the Atankwidi and Afram Catchments in Ghana
    (International Journal of Applied Agricultural Research, 2012-01) Salifu, Tayari; Agyare, W. A.; Kyei-Baffour, Nicholas; Mensah, Ebenezer; Ofori, Emmanuel
    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.