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Publication

Spatial and temporal variability of rainfall in the Nile Basin

Journal Contribution - Journal Article

Spatio-temporal variability in annual and seasonal rainfall totals were assessed at 37
locations of the Nile Basin in Africa using quantile perturbation method. To get insight
into the spatial difference in rainfall statistics, the stations were grouped based on the
pattern of the 5 long-term mean of monthly rainfall and that of temporal variability. To find
the origin of the driving forces for the temporal variability in rainfall, correlation analyses
were carried out using global monthly sea level pressure and surface temperature.
Further investigations to support the obtained correlations were made using a total
of 10 climate indices. It was possible to obtain 3 groups of stations; those within the
10 equatorial region (A), Sudan and Ethiopia (B), and Egypt (C). For group A, annual
rainfall was found to be below (above) the reference during the late 1940s to 1950s
(1960s to mid 1980s). Conversely for groups B and C, the period 1930s to late 1950s
(1960s to 1980s) was characterized by anomalies being above (below) the reference.
For group A, significant linkages were found to Niño 3, Niño 3.4 and the North Atlantic
15 and Indian Ocean drivers. Correlations of annual rainfall of group A with Pacific Oceanrelated
climate indices were inconclusive. With respect to the main wet seasons, the
June to September rainfall of group B has strong connection to the influence from the
Indian Ocean. For the March to May (October to February) rainfall of group A (C),
possible links to the Atlantic and Indian Oceans were found.
Journal: Hydrology and Earth System Sciences Discussions
ISSN: 1812-2108
Volume: 18
Pages: 1-42
Number of pages: 42
Publication year:2014
Keywords:Spatial and temporal variability, rainfall in the Nile Basin