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Climatic trends in Sahel during 1950 - 2014: A case study of Ouaddaï region in Chad

Adam Adey Souleymane, Zine eL Abidine Abdenbi, Mustapha Mahamat Ali, Gmira Najib


This work focused on the study of climatic trends (rainfall and temperature) in the region of Ouaddaï in eastern Chad. Evolution trends and breaks are detected during the most comprehensive measurement period available from 1950 to 2014, using statistical methods. Dry, normal, wet years and temperature anomalies are diagnosed by the application of the standardized index. The       9-year moving average method is used to search for possible internal trends in precipitation and temperature and to identify dry, normal and wet periods. Complete data from only two climatological stations (Abéché and El Geneïna) in the study area are processed. Rainfall shows that the rupture was established in 1964 and for the temperature in 1960. The reduction in rainfall is 21% for the Abéché substation and 20% for the El Geneïna substation. The temperature increase is 18%. Since 1992, the temperature continues to increase until today. By application of the standardized rainfall index, a wet phase was observed from 1950 to 1964, a dry phase from 1965 to 2000 and a phase with a mixture of normal and wet years from 2001 to 2014. These results would be useful to understand the impact of the combined effect of drought and the continuing rise in temperatures on the agricultural, pastoral and forest ecosystems of the study area.

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