Spatial and Temporal Analysis of Evaporation Trends at Gulf of Sirte Stations for the Period 1966-2010

Abstract

The study aims to determine the temporal trend of evaporation and the spatial variation among climatic stations in the Gulf of Sirte over a period of 45 years. It employs several statistical methods, including the trend line equation, the Mann–Kendall test, and Sen's slope estimator, to detect statistically significant temporal trends. The study period was divided into two successive periods: the first from 1966 to 1987, and the second from 1988 to 2010. For graphical representation, cartographic methods, such as maps using Arc Map 10.8, and graphs using Excel were utilized. The results of the study revealed a clear spatial variation, wherein evaporation rates increase from the north towards the southern deserts. The annual increase rate ranged between 5.8 mm/year at the Sirte and Misrata stations and 10.5 mm/year at the Hun station. After applying the trend change equation, evaporation trends exhibited a change in the second period compared to the first period, which had shown a decreasing trend at the Sirte, Benina, and Jalu stations. As for the Mann–Kendall test, it extracted two statistically significant downward trends: at the Sirte station, with a Z-value of -5.28 at a significance level of α = 0.01, and at the Jalu station, with a Z-value of -2.50 at a significance level of α = 0.05.