Changing rainfall, seasonality and erosivity in the hyper‐arid zone of Sudan

Abstract

AbstractA primary cause of soil erosion is the impact of rain. Therefore, understanding the altering rainfall characteristics and their effect on soil erosion is an issue of main concern. This is of utmost importance to contribute to developing suitable adaptation and mitigation strategies for soil and water resources conservation and crop management practices.The rainfall seasonality index (SI), precipitation concentration index (PCI) and modified Fournier index (MFI) for rainfall erosivity have been calculated and analysed in this study for the hyper‐arid region of Sudan. The data used consist of monthly rainfall measurements spanning over 60 years for three index meteorological stations, two on the Nile corridor and one on the Red Sea coast. The region is characterized by high year‐to‐year variability in rainfall leading to extreme seasonality/irregular distribution of rainfall over the year. Although prevalent diminishing rainfall amounts have been witnessed, there are marked tendencies for some months to become wetter, indicating changing intra‐annual rainfall variability and thus monthly rainfall erosivity. No statistically significant trends were observed in rainfall seasonality and concentration during the common data period of 1945–2007. Cases of high and very high erosion powers were detected. A significant decreasing trend in erosivity is shown for one inland station. A brief discussion on the implications of these results for risk of soil erosion, freshwater quality and agriculture is also given. Copyright © 2010 John Wiley & Sons, Ltd.