Variability and trends of rainfall extreme events in north east highlands of Ethiopia

This study was conducted in south Wollo to investigate the spatio-temporal variability of nine extreme rainfall indices and their trends. The daily rainfall was obtained from six meteorological stations in the period (1984-2014). Sen's slope estimator and Mann-Kendall's test were used to determine the magnitude and trends of changes, respectively. The results showed complex patterns of rainfall. Rainfall significantly (P<0.05) increased in summer in some of the stations (Dessie, Haik and Mekaneselam) and showed declining tendency in spring at all studied stations. The mean annual consecutive dry day significantly decreased at Dessie, Haik and Wereilu whereas consecutive wet days significantly increased at Ambamariam, Dessie and Mekaneselam. Trends in mean annual number of wet days, total wet day rainfall and simple daily rainfall intensity index did not show significant changes. The study revealed that rainfall pattern of the studied stations was changed into mono modal (summer) and the inter-annual and seasonal rainfall variability was high. These results highlight the need for planning effective adaptation strategies.