Spatio Temporal Variability of Rainfall Across Western Libya from 1979 to 2009

Aims: To understand the links between climate variability and hydrology in western Libya. Background: This study represents the first comprehensive assessment of rainfall variability in western Libya at a regional scale. Objective: To assess temporal and spatial variability of rainfall in western Libya, based on data (1979-2009) from 16 rain gauges. Methods: The non-parametric Mann-Kendall method and Sen’s slop estimator were used to define changes in rainfall series and their statistical significance. Results: Coastal and mountainous time series showed decreasing trends at the annual, autumn, and spring scales, with very few exceptions. Notably, winter showed increasing trends, with the significant values of 1.94 and 0.88 mm/year at Sirt and Nalut, respectively. Desert stations showed increasing trends, especially at the annual scale, with the greatest significant increase on the order of 1.19 mm/year in Ghadames. For the regional rainfall trend analysis, annual, spring and autumn rainfalls decreased in the coastal and mountainous zones, with the highest significant decrease of 1.94 mm/year. Again, winter rainfall showed increasing trend over the whole study domain. Conclusion: Although most time series showed a tendency towards more drier conditions, most of the detected trends were statistically non-significant. This study will provide guidance for policy makers in their future planning to mitigate the impact of drought.