Abstract
In this study we assess the impact of climate change
on water resources by using uncorrected and bias corrected datafrom the
regional climate model REMO simulations over the Senegal River Basin
(SRB). Both simulations were used asinput of the Max Planck Institute
for Meteorology-Hydrological Model (MPI-HM) over the Upper Senegal Basin
(USB). Applying the bias correction simulations of present day
climate(1971-2000) substantially improved for both temporal and spatial
variations of the analyzed climate parameters (precipitation,
temperature) when compared to interpolated gridded observations and
station data.Additionally, the bias corrected input give better repres
entation of the mean river flow, the low flows(10thpercentile) andthe
high flows (90th percentile) at the outlet of the USB. For the future,
the regional climate model projections for precipitation show a general
decrease by the end of 21st century (2071-2100) for both narios
(Representative Concentration Pathways RCP4.5 and RCP8.5) and
datasets in the majority of the basin, except the Guinean
highlands where a slight increase is found. In case of the
potential changes of the maximum consecutive number of dry days and wet
days, the northern basin is likely to face the most pronounced increase
of dry days and decrease of wet days, although a slight increase of
heavy rainfall is found with similar spatial patterns in both
data. Higher decadal variability of the maximum 5-day precipitation with
the uncorrected data in RCP8.5 is projected, while uncorrected and bias
corrected data depict similar temporal variability for extremely wet
days. Furthermore, a general temperature increase is projected over the
entire basin for both scenarios, but more pronounced under the RCP8.5
scenario. Warm night’s percent is found to be higher than warm day’s
percent. As for the potential changes of the basin’s hydrology, a
general decrease of river discharge, runoff, actual evapotranspiration,
soil moisture is found under RCP4.5 and RCP8.5 in all
simulations. The decrease is higher under RCP8.5 with uncorrected
data in the northern basin. However, there are some localized increases
of runoff in some parts of the basin (e.g.Guinean Highlands).
Furthermore, the available water resources are projected to
substantially decrease by more than -50% in the majority of the basin
for all data, except the southern basin in Guinea where no change is
projected. The impact of the bias correction on the projected climate
change signal, affects mainly the magnitude of the signal rather than
its direction of change although some modifications may occur in
particular months and localities.