On the other hand, despite the noticeable above-normal years
which count as 14 years during 1979e2008 (Fig. 3a), the time
series of rainfall has an insignificant rate of increase for both
the long-term period and the last three decades. The median
rainfall augmented slightly from 1941e1978 to 1979e2008 by
18.8 mm in the annual value and 30.2 mm in the wettest month of
August. Findings by Elagib (2010b) for El Gedaref showed that the
annual rainfall is highly dependent on heavy rainfalls and is
independent of light and medium rainfall events, indicating that
heavy rainfalls are more likely to diminish in drought years and