تحليل فترات الجفاف في محطة زواره خلال الفترة 1990- 2020 باستخدام المؤشر المعياري للتساقط المطري والتبخر(SPEI)

This study aims to evaluate and analyze drought periods in the Zuwara region, located in northwestern Libya, during the period 1990–2020, using the Standardized Precipitation-Evapotranspiration Index (SPEI). Daily data from the Zuwara station, including precipitation amounts and maximum and minimum temperatures, were utilized to calculate the SPEI over four time scales (3, 6, 9, and 12 months) to capture short-, medium-, and long-term drought effects. The results indicated that short-term droughts (SPEI-3) are closely associated with seasonal agricultural drought, whereas SPEI-6 reflects medium-term drought linked to soil moisture. SPEI-9 and SPEI-12 represent long-term drought manifestations and hydrological drought. The years 2000 and 2019 were identified as the driest during the study period, while moderate conditions dominated the majority of months analyzed. Trend analyses using the Mann–Kendall test and Sen’s slope revealed no significant temporal trends in SPEI values, indicating relative stability in drought severity, with seasonal factors largely controlling short-term fluctuations. The study demonstrates the effectiveness of the SPEI in monitoring drought across different time scales and provides a scientific basis for understanding drought dynamics in Zuwara, supporting informed water and agricultural resource management. Keywords: Arid, Standardized Precipitation Evapotranspiration Index, SPEI Studio, Mann–Kendall.