Changing Climate Over Chad: Is the Rainfall Over the Major Cities Recovering?

Chad is the largest country of the Sahel region with different climatic zones, varying from arid in the north to tropical in the south. These climatic zones respond differently to climate change signals. Therefore, their detection over major cities, which are scattered within different climatic zones, is of utmost importance. The changes in hydroclimatic fields such as rainfall and temperature were examined over the major cities in various regions for the period 1950 to 2014. Rainfall shows a significant decreasing trend especially over cities close to Lake Chad (Lere, Mondou, Mongo, and Sarh), whereas no significant trend is observed for cities farther from the Lake. However, a consistently increasing trend in temperature is found across all cities. The cities in the north (Faya, Abeche, and Ati) receive far less rainfall than those located in southern Chad. All cities (except Faya and Lere) received higher rainfall during 1950–1965 (wet period), entering a dry regime between 1966 and 1990 (dry period) and subsequently recovering rainfall totals, toward previous levels, between 1991 and 2014 (recovery phase). A substantial rise in air temperature is observed after 1980–1985, reflecting the gradual rise of temperature in recent times. In summary, rainfall is recovering from a dry regime and temperature is rising over all the major cities of Chad. More researches in this region is needed to develop local scale mitigation strategies and adaptation technology.