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| Titel |
Impacts of climate change on Blue Nile flows using bias-corrected GCM scenarios |
| VerfasserIn |
M. E. Elshamy, I. A. Seierstad, 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 ; 13, no. 5 ; Nr. 13, no. 5 (2009-05-06), S.551-565 |
| Datensatznummer |
250011856
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| Publikation (Nr.) |
 copernicus.org/hess-13-551-2009.pdf |
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| Zusammenfassung |
| This study analyses the output of 17 general circulation models (GCMs)
included in the 4th IPCC assessment report. Downscaled precipitation
and potential (reference crop) evapotranspiration (PET) scenarios for the
2081–2098 period were constructed for the upper Blue Nile basin. These were
used to drive a fine-scale hydrological model of the Nile Basin to assess
their impacts on the flows of the upper Blue Nile at Diem, which accounts
for about 60% of the mean annual discharge of the Nile at Dongola. There
is no consensus among the GCMs on the direction of precipitation change.
Changes in total annual precipitation range between −15% to +14% but
more models report reductions (10) than those reporting increases (7).
Several models (6) report small changes within 5%. The ensemble mean of
all models shows almost no change in the annual total rainfall. All models
predict the temperature to increase between 2°C and 5°C and
consequently PET to increase by 2–14%. Changes to the water balance are
assessed using the Budyko framework. The basin is shown to belong to a
moisture constrained regime. However, during the wet season the basin is
largely energy constrained. For no change in rainfall, increasing PET thus
leads to a reduced wet season runoff coefficient. The ensemble mean runoff
coefficient (about 20% for baseline simulations) is reduced by about
3.5%. Assuming no change or moderate changes in rainfall, the simulations
presented here indicate that the water balance of the upper Blue Nile basin
may become more moisture constrained in the future. |
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