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| Titel |
Model study of the impacts of future climate change on the hydrology of Ganges–Brahmaputra–Meghna basin |
| VerfasserIn |
M. Masood, P. J.-F. Yeh, N. Hanasaki, K. Takeuchi |
| 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 ; 19, no. 2 ; Nr. 19, no. 2 (2015-02-04), S.747-770 |
| Datensatznummer |
250120620
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| Publikation (Nr.) |
 copernicus.org/hess-19-747-2015.pdf |
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| Zusammenfassung |
| The intensity, duration, and geographic extent of floods in Bangladesh
mostly depend on the combined influences of three river systems, the Ganges,
Brahmaputra and Meghna (GBM). In addition, climate change is likely to have
significant effects on the hydrology and water resources of the GBM basin
and may ultimately lead to more serious floods in Bangladesh. However, the
assessment of climate change impacts on the basin-scale hydrology by using
well-calibrated hydrologic modeling has seldom been conducted in the GBM basin
due to the lack of observed data for calibration and validation. In this
study, a macroscale hydrologic model H08 has been applied over the basin at
a relatively fine grid resolution (10 km) by integrating the fine-resolution
DEM (digital elevation model) data for accurate river networks delineation. The model has been
calibrated via the analysis of model parameter sensitivity and validated based on
long-term observed daily streamflow data. The impacts of climate change
(considering a high-emissions path) on runoff, evapotranspiration, and soil
moisture are assessed by using five CMIP5 (Coupled Model Intercomparison Project Phase 5) GCMs (global circulation models) through three time-slice
experiments; the present-day (1979–2003), the near-future (2015–2039), and
the far-future (2075–2099) periods. Results show that, by the end of
21st century, (a) the entire GBM basin is projected to be warmed by
~4.3 °C; (b) the changes of mean precipitation
(runoff) are projected to be +16.3% (+16.2%), +19.8%
(+33.1%), and +29.6% (+39.7%) in the Brahmaputra, Ganges, and
Meghna, respectively; and (c) evapotranspiration is projected to increase for the
entire GBM (Brahmaputra: +16.4%, Ganges: +13.6%, Meghna:
+12.9%) due to increased net radiation as well as warmer temperature.
Future changes of hydrologic variables are larger in the dry season
(November–April) than in the wet season (May–October). Amongst the three basins, the
Meghna shows the highest increase in runoff, indicating higher possibility
of flood occurrence. The uncertainty due to the specification of key model
parameters in model predictions is found to be low for estimated runoff,
evapotranspiration and net radiation. However, the uncertainty in estimated
soil moisture is rather large with the coefficient of variation ranging from 14.4 to
31% among the three basins. |
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