Inter-annual variation of the mean temperature and rainfall in Chad and the solar activity during the period from 1950 to 2020

Given the increased variability of rainfall, the resurgence of extreme meteorological phenomena such as droughts, floods, heat waves, and violent winds and considering the influence of solar activity on certain meteorological parameters, a study on the variation of temperature and rainfall in relation to solar activity is necessary. The present study aimed to analyze the inter-annual evolution of meteorological parameters (mean temperature and rainfall) in Chad over the period from 1950 to 2020 in two geographically distinct areas (Sudanian and Sahelian zone) and then to establish a link between these parameters and solar activity to predict the variations of these two parameters over time. The rainfall results showed that the wettest years were 1959 in N'Djamena and 1951 in Moundou. On the other hand, the driest years recorded were 1984 in N'Djamena and 1998 in Moundou. The study of the mean temperature in these two areas during the same period led to the conclusion that the hottest year was 2010 in N'Djamena; however, in Moundou the hottest year recorded was 1997. Globally, in the two zones concerned, analysis of the results on variations in rainfall showed a downward trend. However, the study of average temperature showed a steady rise over the same period. The superposition of rainfall and mean temperature with the sunspot numbers Rz led to the conclusion that high sunspot activity increases temperature and thus warming, while low sunspot activity brings high precipitation.