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| Titel |
A hydrogeologic framework for characterizing summer streamflow sensitivity to climate warming in the Pacific Northwest, USA |
| VerfasserIn |
M. Safeeq, G. E. Grant, S. L. Lewis, M. G. Kramer, B. Staab |
| 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 ; 18, no. 9 ; Nr. 18, no. 9 (2014-09-24), S.3693-3710 |
| Datensatznummer |
250120475
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| Publikation (Nr.) |
 copernicus.org/hess-18-3693-2014.pdf |
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| Zusammenfassung |
| Summer streamflows in the Pacific Northwest are largely derived from melting
snow and groundwater discharge. As the climate warms, diminishing snowpack
and earlier snowmelt will cause reductions in summer streamflow. Most
regional-scale assessments of climate change impacts on streamflow use
downscaled temperature and precipitation projections from general circulation
models (GCMs) coupled with large-scale hydrologic models. Here we develop and
apply an analytical hydrogeologic framework for characterizing summer
streamflow sensitivity to a change in the timing and magnitude of recharge in
a spatially explicit fashion. In particular, we incorporate the role of deep
groundwater, which large-scale hydrologic models generally fail to capture,
into streamflow sensitivity assessments. We validate our analytical
streamflow sensitivities against two empirical measures of sensitivity
derived using historical observations of temperature, precipitation, and
streamflow from 217 watersheds. In general, empirically and analytically
derived streamflow sensitivity values correspond. Although the selected
watersheds cover a range of hydrologic regimes (e.g., rain-dominated, mixture
of rain and snow, and snow-dominated), sensitivity validation was primarily
driven by the snow-dominated watersheds, which are subjected to a wider range
of change in recharge timing and magnitude as a result of increased
temperature. Overall, two patterns emerge from this analysis: first, areas
with high streamflow sensitivity also have higher summer streamflows as
compared to low-sensitivity areas. Second, the level of sensitivity and
spatial extent of highly sensitive areas diminishes over time as the summer
progresses. Results of this analysis point to a robust, practical, and
scalable approach that can help assess risk at the landscape scale,
complement the downscaling approach, be applied to any climate scenario of
interest, and provide a framework to assist land and water managers in
adapting to an uncertain and potentially challenging future. |
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