Assessment of Drought and Rainfall Extremes at the Stations (Tripoli, Sirte, Shahat) for the Period (1991–2020) and Their Climate and Environmental Implications Using the Standardized Precipitation Index

Abstract

This study aimed to evaluate periods of drought and heavy rainfall at three meteorological stations in Libya (Shahat, Tripoli, and Sirte) over a 30-year period, and to track their climatic and environmental impacts using a standardized rainfall index. The results of the statistical analysis showed that periods of heavy rainfall exceeded periods of drought at all three stations during the study period. The general characteristics were similar at the Shahat and Tripoli stations, each recording 14 rainy years (47%), nine dry years (30%), and seven moderate transitional years (23%). In contrast, the Sirte station recorded 13 rainy years (43%), eight dry years (27%), and nine moderate years (30%). Regarding extreme weather events, the number of the most severe years varied among the stations. Shahat recorded the highest rainfall in the last year of the study and the most severe drought in 2013. In contrast, Tripoli recorded the highest humidity in 2016 and the most severe drought in 1993. Sirte experienced the most severe drought in 2017 and the highest humidity in 1993. These findings indicate clear climatic fluctuations, tending towards heavy rainfall and high humidity, followed by a significant increase in drought years. This leads to varying environmental problems, including increased risks of surface runoff and soil erosion during years of high humidity, and challenges to vegetation and water resources during drought years. The study recommends developing flexible water resource management strategies capable of adapting to this sharp fluctuation in rainfall patterns.