Climate Change and Sensitivity of Surface Water Resources in the Mekrou Sub-Watershed at the Yakrigourou Outlet (North Benin / West Africa)
Alain Ibikunle Ague,
Cyr Gervais Etene,
Somiyabalo Pilabina,
Ibouraima Yabi
Issue:
Volume 9, Issue 3, June 2021
Pages:
60-66
Received:
9 April 2021
Accepted:
5 May 2021
Published:
20 May 2021
Abstract: The present work aims to contribute to a better understanding of the impacts of climate change on the availability of surface water resources in the Mékrou sub-basin at the Yakrigourou outlet in northern Benin. To achieve this objective, descriptive statistical methods were applied to hydro-climatological data. The historical data were taken from the Météo-Bénin database and from the General Directorate of Water in Benin. The simulation data are those of the HadGEM2-ES climate model under the RCP 4.5 and RCP 8.5 scenarios and then at horizons 50 (2041 to 2060) and 70 (2061 to 2080). The results show that the period from 1965 to 2018 is globally characterised by a strong irregularity of rainfall with a decreasing trend and a multiplication of dry years estimated at 54%. In the same way, the runoff decrease about 5.8 m3/s during the decade 2007-2016. Under the most pessimistic scenario (RCP8.5) and compared to the reference period (1971-1990), the HadGEM2-ES model predicts an increase in annual precipitation estimated at 8.29% by 2041-2060 and 13.83% by 2061-2080. As regards temperature, there could be an increase of 2.4°C by 2041-2060 and 3.7°C by 2061-2080. These climatic events affect the availability of surface water resources in the sub-basin.
Abstract: The present work aims to contribute to a better understanding of the impacts of climate change on the availability of surface water resources in the Mékrou sub-basin at the Yakrigourou outlet in northern Benin. To achieve this objective, descriptive statistical methods were applied to hydro-climatological data. The historical data were taken from t...
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Interannual Variability of Seasonal Rainfall and Associated Circulations over Gambella, Ethiopia
Waza Mulualem Abera,
Wang Wen
Issue:
Volume 9, Issue 3, June 2021
Pages:
67-95
Received:
14 April 2021
Accepted:
7 June 2021
Published:
16 June 2021
Abstract: Ethiopia composes diversified topographic structures; undulated plateaus and mountains, raged valleys and plains. The highlands and ever-green portions of the county are fringed by the Sahara and Arabian deserts as well as East African arid climates. This study investigates the spatial and temporal seasonal (June-September [JJAS]) rainfall variability and the associated circulation patterns over Ethiopia. The study utilized ten daily station gridded rainfall, monthly SST, Outgoing Longwave Radiation (OLR) and zonal and meridional wind at various levels for 1983-2015. Statistical methods employed include EOF, composite and correlation analysis. The three leading EOF analysis revealed 57.8% that the first and second PC modes over Gambella are associated with ENSO and IOD variability. Wind and velocity potential revealed that wet (dry) years were characterized by convergence (divergence) in the lower level and divergence (convergence) at the upper level, implying rising (sinking) motion over the study area and western Indian Ocean. During normal (wet) years, maximum intensity of westerlies was generally observed at 850 hPa level, while easterlies were dominant at the upper level. There exists a significant correlation between JJAS rainfall and Nino3.4 for ENSO with r value (-0.56) but insignificant for (DMI) IOD with r value (-0.11). A cold (warm) summer SST over the central equatorial Pacific is associated with more (less) rainfall over Ethiopia. This shows that both ENSO and IOD modes have influence on rainfall variability during main rainy season. The findings of this and related studies is crucial to the development, planning and mitigation of all rainfall dependent activities.
Abstract: Ethiopia composes diversified topographic structures; undulated plateaus and mountains, raged valleys and plains. The highlands and ever-green portions of the county are fringed by the Sahara and Arabian deserts as well as East African arid climates. This study investigates the spatial and temporal seasonal (June-September [JJAS]) rainfall variabil...
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