An Analysis of Precipitation Extreme Events Based on the SPI and EDI Values in the Free State Province, South Africa

Recognizing that, over the last several years, extreme rainfall has led to hazardous stress in humans, animals, plants, and even infrastructure, present study, we aimed investigate characteristics of droughts Free State (FS) Province South Africa order determine future likelihood reoccurrences precipitation extremes using generalized value distribution (GEV) frequency analysis (EFA). In this regard, daily datasets from nine African weather service homogenous climatic districts, spanning 1980 2019, were used compute: (a) total annual rainfall, (b) Effective Drought Index (EDI), (c) Standard Precipitation (SPI). The SPI was calculated for 3, 6, 12 month accumulation periods (hereafter SPI-3, SPI-6, SPI-12, respectively). trend results EDI -6, -12 showed that is generally negative, illustrating persistent drought. An GEV parameters across values illustrated location, scale, shape exhibited a noticeable spatial variability with location parameter largely scale positive, while pointed an inherent Type III (Weibull) distribution. addition, return levels drought/wet duration severity increasing patterns corresponding periods; contrasts only derived wet/drought (and not EDI). Further, EFA contrast each categories: moderately wet, severely extremely wet dry, dry. Over four decades, FS experienced suite categories ranging dry conditions. Overall, study contributes towards implementation effective drought early warning systems can be enhance related policy decision making support water resource management planning Province.