An assessment of rainfall variability in northern Egypt

The aim of the current study is to monitor and analyze the rainfall variability and to predict the aridity in northern Egypt. To implement that, parametric and non-parametric statistical methods were used for the rainfall data at 13 meteorological stations scattered along the study area from 1947 to 2010. Standard normal homogeneity test, linear regression forecasting methods, Mann-Kendall’s test for trend, time-series plots, the trend-to-noise ratio as a test of significance for the annual and seasonal rainfall, the annual rainfall intensity, inter- and intra-annual variability, and seasonality were calculated. High inter-annual and intra-annual rainfall variability has been observed over space and time. Synchronously, different temporal patterns of annual rainfall were noticed at different stations, and most of the trends were not linear and significant. The results indicated an increase in the number of years, which receive less than the average rainfall. In addition, a marked variation in seasonal rainfall was observed every decade, and the rainfall variability of autumn was higher than that in winter and spring while summer experienced no rainfall and, hence, no variability. In the future, precipitation will decrease overall the region with an increase in temperature for all stations, where the existence of droughts may possibly arise in northern Egypt based on the ensemble mean of multi-Coordinated Regional climate Downscaling Experiment models under RCP4.5 and RCP8.5 emission scenarios. The outcomes of this research can be beneficial for drought hazard mitigation as well as for the preparation and managing agricultural activities in the study area.