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| Titel |
Quantifying uncertainty in the impacts of climate change on river discharge in sub-catchments of the Yangtze and Yellow River Basins, China |
| VerfasserIn |
H. Xu, R. G. Taylor, Y. Xu |
| 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 ; 15, no. 1 ; Nr. 15, no. 1 (2011-01-26), S.333-344 |
| Datensatznummer |
250012606
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| Publikation (Nr.) |
 copernicus.org/hess-15-333-2011.pdf |
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| Zusammenfassung |
| Quantitative evaluations of the impacts of climate change on water resources
are primarily constrained by uncertainty in climate projections from GCMs.
In this study we assess uncertainty in the impacts of climate change on
river discharge in two catchments of the Yangtze and Yellow River Basins
that feature contrasting climate regimes (humid and semi-arid). Specifically
we quantify uncertainty associated with GCM structure from a subset of CMIP3
AR4 GCMs (HadCM3, HadGEM1, CCSM3.0, IPSL, ECHAM5, CSIRO, CGCM3.1), SRES
emissions scenarios (A1B, A2, B1, B2) and prescribed increases in global
mean air temperature (1 °C to 6 °C). Climate projections, applied to
semi-distributed hydrological models (SWAT 2005) in both catchments,
indicate trends toward warmer and wetter conditions. For prescribed warming
scenarios of 1 °C to 6 °C, linear increases in mean annual river
discharge, relative to baseline (1961–1990), for the River Xiangxi and River
Huangfuchuan are +9% and 11% per +1 °C respectively. Intra-annual
changes include increases in flood (Q05) discharges for both rivers as well
as a shift in the timing of flood discharges from summer to autumn and a
rise (24 to 93%) in dry season (Q95) discharge for the River Xiangxi.
Differences in projections of mean annual river discharge between SRES
emission scenarios using HadCM3 are comparatively minor for the River
Xiangxi (13 to 17% rise from baseline) but substantial (73 to 121%)
for the River Huangfuchuan. With one minor exception of a slight (−2%)
decrease in river discharge projected using HadGEM1 for the River Xiangxi,
mean annual river discharge is projected to increase in both catchments
under both the SRES A1B emission scenario and 2° rise in global
mean air temperature using all AR4 GCMs on the CMIP3 subset. For the River
Xiangxi, there is substantial uncertainty associated with GCM structure in
the magnitude of the rise in flood (Q05) discharges (−1 to 41% under SRES
A1B and −3 to 41% under 2° global warming) and dry season (Q95)
discharges (2 to 55% under SRES A1B and 2 to 39% under 2°
global warming). For the River Huangfuchuan, all GCMs project a rise in the
Q05 flow but there is substantial uncertainty in the magnitude of this rise
(7 to 70% under SRES A1B and 2 to 57% under 2° global
warming). Differences in the projected hydrological changes are associated
with GCM structure in both catchments exceed uncertainty in emission
scenarios. Critically, estimated uncertainty in projections of mean annual
flows is less than that calculated for extreme (Q05, Q95) flows. The common
approach of reporting of climate change impacts on river in terms of mean
annual flows masks the magnitude of uncertainty in flows that are of most
importance to water management. |
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