Characterization of climatic aridity in the groundnut basin, Senegal

Abstract: Understanding of climate aridity is an important step towards assessing the availability of water in a given area. This understanding requires an appropriate analysis allowing monitoring the spatio-temporal evolution of the parameters which act on the availability of water. In this study, we used annual rainfall and temperatures from 5 synoptic stations in the groundnut basin over the period 1965-2014. The study is essentially based on a quantitative and qualitative examination of the Lang, Martonne and hydrothermal indices. It is for us to extract information that can guide agricultural planning choices. The results obtained show that the groundnut basin actually experienced aridity phenomena during the study period. For the five regional stations, there are three degrees of aridity, namely semi-arid, arid and hyper-arid. In terms of duration and frequency, Louga stands out as the most affected and Kaolack the least affected by the aridity phenomenon. In terms of water balance, Fatick seems to be the most affected and Louga the least affected for the water deficit. In terms of heat balance, Louga stands out as the warmest and Thies the least hot. A comparison of the three indices has led to the conclusion that the Martonne aridity index remains very satisfactory for studies of a regional nature. These results thus highlight the great vulnerability of the area to drying up and global warming, especially from north to south. Indeed, an increasing decrease in precipitation and temperatures was observed during the period under review, which widened the gap between the amount of precipitation and the demand for water in agriculture.