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| Titel |
Uncertainty in climate change projections of discharge for the Mekong River Basin |
| VerfasserIn |
D. G. Kingston, J. R. Thompson, G. Kite |
| 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. 5 ; Nr. 15, no. 5 (2011-05-13), S.1459-1471 |
| Datensatznummer |
250012781
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| Publikation (Nr.) |
 copernicus.org/hess-15-1459-2011.pdf |
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| Zusammenfassung |
| The Mekong River Basin is a key regional resource in Southeast Asia for
sectors that include agriculture, fisheries and electricity production. Here
we explore the potential impacts of climate change on freshwater resources
within the river basin. We quantify uncertainty in these projections
associated with GCM structure and climate sensitivity, as well as from
hydrological model parameter specification. This is achieved by running
pattern-scaled GCM scenarios through a semi-distributed hydrological model
(SLURP) of the basin. Pattern-scaling allows investigation of specific
thresholds of global climate change including the postulated 2 °C
threshold of "dangerous" climate change. Impacts of a 2 °C rise in
global mean temperature are investigated using seven different GCMs,
providing an implicit analysis of uncertainty associated with GCM structure.
Analysis of progressive changes in global mean temperature from 0.5 to
6 °C above the 1961–1990 baseline (using the HadCM3 GCM) reveals a relatively
small but non-linear response of annual river discharge to increasing global
mean temperature, ranging from a 5.4 % decrease to 4.5 % increase.
Changes in mean monthly river discharge are greater (from −16 % to
+55 %, with greatest decreases in July and August, greatest increases in
May and June) and result from complex and contrasting intra-basin changes in
precipitation, evaporation and snow storage/melt. Whilst overall results are
highly GCM dependent (in both direction and magnitude), this uncertainty is
primarily driven by differences in GCM projections of future precipitation.
In contrast, there is strong consistency between GCMs in terms of both
increased potential evapotranspiration and a shift to an earlier and less
substantial snowmelt season. Indeed, in the upper Mekong (Lancang
sub-basin), the temperature-related signal in discharge is strong enough to
overwhelm the precipitation-related uncertainty in the direction of change
in discharge, with scenarios from all GCMs leading to increased river flow
from April–June and decreased flow from July–August. |
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