Geographical Distribution and Trends of Annual Rainfall Amounts in Misurata Municipality During the Period 1958–2023

Abstract

This study aims to analysis the spatial distribution of annual rainfall amounts and assess their overall trends through the development of a Climate Database using the Geographic Information System (GIS). The research problem lies in the absence of a digital map that accurately represents the spatial patterns of annual rainfall distribution and their trends, whether increasing or decreasing, in Misurata Municipality for the period 1958–2023. The study adopts a quantitative analytical approach, employing the Mann–Kendall test and the t-test to identify trends in annual rainfall variability at a significance level of 0.05. In addition, GIS techniques are utilized to produce climatic maps that illustrate changes between the two study periods, based on monthly data obtained from the Global Climate Database for 12 meteorological observation points in Misurata Municipality. Spatial analysis tools and interpolation methods are applied to generate high-resolution spatial representations of rainfall distribution. The results indicate a general decreasing trend in annual rainfall across all study locations in Misurata. All trend coefficients and Sen’s slope values were negative, confirming a consistent decline in rainfall amounts over time. This decreasing trend was statistically significant at the 0.05 level in Abu Qurayn and Bir Dufan stations, while the remaining stations exhibited non-significant decreasing trends. The study further produced high-resolution climatic maps illustrating the spatial distribution of annual rainfall and its temporal changes in Misurata Municipality over the study period (1958–2023).