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| Titel |
Hydrological drought across the world: impact of climate and physical catchment structure |
| VerfasserIn |
H. A. J. Lanen, N. Wanders, L. M. Tallaksen, A. F. Loon |
| 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 ; 17, no. 5 ; Nr. 17, no. 5 (2013-05-02), S.1715-1732 |
| Datensatznummer |
250018867
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| Publikation (Nr.) |
 copernicus.org/hess-17-1715-2013.pdf |
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| Zusammenfassung |
| Large-scale hydrological drought studies have demonstrated spatial
and temporal patterns in observed trends, and considerable difference exists
among global hydrological models in their ability to reproduce these
patterns. In this study a controlled modeling experiment has been set up to systematically
explore the role of climate and physical catchment structure (soils
and groundwater systems) to better understand underlying
drought-generating mechanisms. Daily climate data (1958–2001) of
1495 grid cells across the world were selected that represent
Köppen–Geiger major climate types. These data were fed into
a conceptual hydrological model. Nine realizations of physical catchment
structure were defined for each grid cell, i.e., three soils with
different soil moisture supply capacity and three groundwater
systems (quickly, intermediately and
slowly responding). Hydrological drought characteristics (number,
duration and standardized deficit volume) were identified from time
series of daily discharge. Summary statistics showed that the
equatorial and temperate climate types (A- and C-climates) had about
twice as many drought events as the arid and polar types (B- and
E-climates), and the durations of more extreme droughts were about
half the length. Selected soils under permanent grassland were found to have a minor effect on
hydrological drought characteristics, whereas groundwater systems
had major impact. Groundwater systems strongly controlled the
hydrological drought characteristics of all climate types, but
particularly those of the wetter A-, C- and D-climates because of
higher recharge. The median number of droughts for quickly responding
groundwater systems was about three times higher than for
slowly responding systems. Groundwater systems substantially affected the
duration, particularly of the more extreme drought events. Bivariate
probability distributions of drought duration and standardized
deficit for combinations of Köppen–Geiger climate, soil and
groundwater system showed that the responsiveness of the groundwater system
is as important as climate for hydrological drought development. This urges for an improvement of
subsurface modules in global hydrological models to be more useful for
water resources assessments. A foreseen higher
spatial resolution in large-scale models would enable a better hydrogeological
parameterization and thus inclusion of lateral flow. |
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