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| Titel |
Coupled daily streamflow and water temperature modelling in large river basins |
| VerfasserIn |
M. T. H. Vliet, J. R. Yearsley, W. H. P. Franssen, F. Ludwig, I. Haddeland, D. P. Lettenmaier, P. Kabat |
| 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. 11 ; Nr. 16, no. 11 (2012-11-21), S.4303-4321 |
| Datensatznummer |
250013576
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| Publikation (Nr.) |
 copernicus.org/hess-16-4303-2012.pdf |
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| Zusammenfassung |
| Realistic estimates of daily streamflow and water temperature are required
for effective management of water resources (e.g. for electricity and drinking
water production) and freshwater ecosystems. Although hydrological and
process-based water temperature modelling approaches have been successfully
applied to small catchments and short time periods, much less work has been
done at large spatial and temporal scales. We present a physically based
modelling framework for daily river discharge and water temperature
simulations applicable to large river systems on a global scale. Model
performance was tested globally at 1/2 × 1/2° spatial resolution
and a daily time step for the period 1971–2000. We made specific evaluations
on large river basins situated in different hydro-climatic zones and
characterized by different anthropogenic impacts. Effects of anthropogenic
heat discharges on simulated water temperatures were incorporated by using
global gridded thermoelectric water use datasets and representing thermal
discharges as point sources into the heat advection equation. This resulted
in a significant increase in the quality of the water temperature
simulations for thermally polluted basins (Rhine, Meuse, Danube and
Mississippi). Due to large reservoirs in the Columbia which affect
streamflow and thermal regimes, a reservoir routing model was used. This
resulted in a significant improvement in the performance of the river
discharge and water temperature modelling. Overall, realistic estimates were
obtained at daily time step for both river discharge (median normalized
BIAS = 0.3; normalized RMSE = 1.2; r = 0.76) and water temperature (median
BIAS = −0.3 °C; RMSE = 2.8 °C; r = 0.91) for the entire validation period,
with similar performance during warm, dry periods. Simulated water
temperatures are sensitive to headwater temperature, depending on resolution
and flow velocity. A high sensitivity of water temperature to river
discharge (thermal capacity) was found during warm, dry conditions. The
modelling approach has potential to be used for risk analyses and studying
impacts of climate change and other anthropogenic effects (e.g. thermal
pollution, dams and reservoir regulation) on large rivers. |
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