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| Titel |
Sensitivity of SWAT simulated streamflow to climatic changes within the Eastern Nile River basin |
| VerfasserIn |
D. T. Mengistu, A. Sorteberg |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1027-5606
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| Digitales Dokument |
URL |
| Erschienen |
In: Hydrology and Earth System Sciences ; 16, no. 2 ; Nr. 16, no. 2 (2012-02-09), S.391-407 |
| Datensatznummer |
250013171
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| Publikation (Nr.) |
 copernicus.org/hess-16-391-2012.pdf |
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| Zusammenfassung |
The hydrological model SWAT was run with daily station based precipitation
and temperature data for the whole Eastern Nile basin including the three
subbasins: the Abbay (Blue Nile), BaroAkobo and Tekeze. The daily and
monthly streamflows were calibrated and validated at six outlets with
station-based streamflow data in the three different subbasins. The model
performed very well in simulating the monthly variability while the
validation against daily data revealed a more diverse performance. The
simulations indicated that around 60% of the average annual rainfalls of
the subbasins were lost through evaporation while the estimated runoff
coefficients were 0.24, 0.30 and 0.18 for Abbay, BaroAkobo and Tekeze
subbasins, respectively. About half to two-thirds of the runoff could be
attributed to surface runoff while the other contributions came from
groundwater.
Twenty hypothetical climate change scenarios (perturbed temperatures and
precipitation) were conducted to test the sensitivity of SWAT simulated
annual streamflow. The result revealed that the annual streamflow
sensitivity to changes in precipitation and temperature differed among the
basins and the dependence of the response on the strength of the changes was
not linear. On average the annual streamflow responses to a change in
precipitation with no temperature change were 19%, 17%, and 26%
per 10% change in precipitation while the average annual streamflow
responses to a change in temperature and no precipitation change were −4.4% K−1, −6.4% K−1, and −1.3% K−1 for Abbay, BaroAkobo
and Tekeze river basins, respectively.
47 temperature and precipitation scenarios from 19 AOGCMs participating
inCMIP3 were used to estimate future changes in streamflow due to climate
changes. The climate models disagreed on both the strength and the direction
of future precipitation changes. Thus, no clear conclusions could be made
about future changes in the Eastern Nile streamflow. However, such types of
assessment are important as they emphasise the need to use several an
ensemble of AOGCMs as the results strongly dependent on the choice of
climate models. |
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