DETECTION OF INHOMOGENEITIES AND BREAK POINTS IN ANNUAL RAINFALL SERIES OF SENEGALREGIONS

Abstract

Annual rainfall data used in this study was provided by National Agency of Civil Aviation and Meteorology measured in 14 stations of 14 regions of Senegal. Standard normal homogeneity test was performed on these data to detect possible climatic accidents. Our main goal was to provide national decision-makers with plausible scenarios of climate change for all regions of the country. It is to equip them to: i) adapt their natural resource management strategies to climate change issues; and ii) strengthen the scientific base for their own benefit. For all 14 stations, the null hypothesis of no break is rejected at the 5% threshold and the break dates are between 1955 and 1971 depending on the region. The comparison of averages across the breaking point shows that this break is down for all 14 stations. The characterization of the mean amplitudes before and after rupture shows that this decrease did not have the same intensity in the 14 regions. Finally, the characterization of the wet and dry sequences shows that the temporal persistence of the drought is not at the same level for the 14 regions. In conclusion, the statistical analysis of the rainfall contributions confirms the dissymmetry and the general downward trend and therefore the low water level in Senegal. Such results suggest the need for water authorities to formulate effective water management policies according to the prevailing and future climatic conditions. Transitional, adaptive and urgent measures may be undertaken by priority according regions.