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Titel |
Global hydrological droughts in the 21st century under a changing hydrological regime |
VerfasserIn |
N. Wanders, Y. Wada, H. A. J. Van Lanen |
Medientyp |
Artikel
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Sprache |
Englisch
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ISSN |
2190-4979
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Digitales Dokument |
URL |
Erschienen |
In: Earth System Dynamics ; 6, no. 1 ; Nr. 6, no. 1 (2015-01-06), S.1-15 |
Datensatznummer |
250115410
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Publikation (Nr.) |
copernicus.org/esd-6-1-2015.pdf |
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Zusammenfassung |
Climate change very likely impacts future hydrological drought
characteristics across the world. Here, we quantify the impact of
climate change on future low flows and associated hydrological
drought characteristics on a global scale using an alternative
drought identification approach that considers adaptation to future
changes in hydrological regime. The global hydrological model
PCR-GLOBWB was used to simulate daily discharge at 0.5°
globally for 1971–2099. The model was forced with CMIP5 climate
projections taken from five global circulation models (GCMs) and four emission scenarios (representative concentration pathways, RCPs),
from the Inter-Sectoral Impact Model Intercomparison Project.
Drought events occur when discharge is below a threshold. The
conventional variable threshold (VTM) was calculated by deriving the
threshold from the period 1971–2000. The transient variable
threshold (VTMt) is a non-stationary approach,
where the threshold is based on the discharge values of the previous
30 years implying the threshold to vary every year during the 21st
century. The VTMt adjusts to gradual changes in
the hydrological regime as response to climate change.
Results show a significant negative trend in the low flow regime
over the 21st century for large parts of South America, southern
Africa, Australia and the Mediterranean. In 40–52% of the
world reduced low flows are projected, while increased low flows are
found in the snow-dominated climates.
In 27% of the global area both the drought duration and the
deficit volume are expected to increase when applying the
VTMt. However, this area will significantly
increase to 62% when the VTM is applied. The mean global area
in drought, with the VTMt, remains rather
constant (11.7 to 13.4%), compared to the substantial
increase when the VTM is applied (11.7 to 20%).
The study illustrates that an alternative drought identification
that considers adaptation to an altered hydrological regime has
a substantial influence on future hydrological drought characteristics. |
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