Historical Change in Extreme Precipitation in Sudan and Associated Physical Mechanism

Rain is the lifeblood of the Sudanese economy; therefore, rain studies are of concern to many researchers. This study is a continuation of previous studies. This study was conducted to determine the changes in extreme rainfall indices in Sudan from 1981 to 2020, as well as to determine the relationship between extreme rainfall indices and rainfall drivers, such as El Niño Southern Oscillation and Indian Ocean Dipole (ENSO/IOD). We used satellite daily rainfall data (CHIRPS). The study found that June to September (JJAS) had the highest rainfall rate. According to the rainfall rate data, we chose Consecutive Wet Days (CWD), Maximum 5-day precipitation (RX5day), and Severe precipitation days (R20mm) to represent the indices that have been calculated. To evaluate the index results, we divided the targeted stations into four categories for discussion (Type 1, Type 2, Type 3, and Type 4). For the stations included in each class, we calculated the average of the three indices to obtain the average precipitation index of these classes. This study aimed to investigate the relationship between extreme rainfall indices and rainfall drivers like ENSO/IOD. The study found variability in extreme rainfall indices during the study period, and this variability was distributed from south to north according to the climatic zones. In addition, there is a strong relationship between extreme rainfall indices and drivers, particularly during winter.