rainfall variability

Abstract

This article focuses on studying and analyzing rainfall variability in the Sahel area with a case study from Sudan. The main objective of the article is to analysis the rainfall variation over both space and time during the last four decades. The data for rainfall variability was collected from five meteorological stations namely, Elobied, EnNuhud, Elfashir, Nyala, and Elginaina for the period 1970-2010 including four strong Elnino events. The descriptive and statistical analytical methods, the mean, standard deviation, coefficient of variation and Geographical Information System (GIS) have been used for data analysis. The results show that rainfall is highly fluctuated and varied over both space and time indicating a real variation in annual average rainfall values. the coefficient of variation ranges between 0.22 to 0.37 and the standard deviation ranges between 76 to 127.6 which are presented in GIS formats. Results also show a successive decade of small rainfall variatbility followed by a decade of high rainfall variability. Two positive and four negative anomalies have been found during the period 1970-2010.