Spatial and temporal variability of rainfall in the Nile Basin
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Date
2015
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Hydrology and Earth System Sciences
Abstract
Spatiotemporal variability in annual and seasonal
rainfall totals were assessed at 37 locations of the Nile Basin
in Africa using quantile perturbation method (QPM). To get
insight into the spatial difference in rainfall statistics, the stations
were grouped based on the pattern of the long-term
mean (LTM) 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 (SLP) and
sea surface temperature (SST). Further investigations to support
the obtained correlations were made using a total of
10 climate indices. It was possible to obtain three groups
of stations; those within the 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 from 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 Ocean
and Indian Ocean drivers. Correlations of annual rainfall of
group A with Pacific Ocean-related climate indices were inconclusive.
With respect to the main wet seasons, the June–
September rainfall of group B has strong connection to
the influence from the Indian Ocean. For the March–May
(October–February) rainfall of group A (C), possible links
to the Atlantic and Indian oceans were found.
Description
Keywords
Rainfall, Nile Basin
Citation
Onyutha, C., & Willems, P. (2015). Spatial and temporal variability of rainfall in the Nile Basin. Hydrology and Earth System Sciences , 19 (5), 2227-2246. doi:10.5194/hess-19-2227-2015