Thesis (M.Sc.) - Cairo University - Faculty of African Postgraduate Studies - Department of Natural Resources

The objective of this thesis is to study spatial and temporal variations in rainfall in the study area (Northern of Egypt and Libya).18 rain gauge stations located in Northern of Egypt and Libya with rainfall time series from 1960 to 2016 were used, Seasonal and annual rainfall values measured were analyzed. Rainfall in the study area is mainly affected by low pressure areas (depressions) across the Mediterranean basin associated with a branch of the westerly jet stream. The annual total rainfall of the study area varies from a little over 834.8 mm in Shahat station to over 28.3 mm in Port Said station. The study showed decreasing rainfall trends at all 11 stations in total annual and seasonal. Annually, the magnitude of the trend varied from -6.155 mm year{u2013}1 in Shahat to -0.627 mm year{u2013}1 in Derna station. Rainfall variability coefficient is utilized to analyse the past data situation and the study covers the period from 1960-2016. According to the statistical test for coefficient of variation was moderate in five stations, was high in ten stations, and three stations had very high coefficient of variation, from the observed data considered that all stations had coefficient of variation above 25% that is highlighting the high variability of rainfall over the zone through the study period. There is high spatial variability between stations, and temporal variability for each station, in consequence, there are several anomalies in rainfall in recent years. The study found that there was moderate interannual rainfall variability across the studied stations. However, it was lowest during winter season. Quadratic regression model for total annual rainfall in the study area showed decreasing at most of the stations (14 out of 18 stations). The highest value for R2 was at quadratic equation at all stations so quadratic equation is the best to express the trend equation than the other equations

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