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| Titel |
A generic method for hydrological drought identification across different climate regions |
| VerfasserIn |
M. H. J. Huijgevoort, P. Hazenberg, H. A. J. Lanen, R. Uijlenhoet |
| 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 ; 16, no. 8 ; Nr. 16, no. 8 (2012-08-03), S.2437-2451 |
| Datensatznummer |
250013404
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| Publikation (Nr.) |
 copernicus.org/hess-16-2437-2012.pdf |
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| Zusammenfassung |
| The identification of hydrological drought at global scale has received
considerable attention during the last decade. However, climate-induced
variation in runoff across the world makes such analyses rather complicated.
This especially holds for the drier regions of the world (both cold and
warm), where, for a considerable period of time, zero runoff can be observed.
In the current paper, we present a method that enables to identify drought at
global scale across climate regimes in a consistent manner. The method
combines the characteristics of the classical variable threshold level method
that is best applicable in regions with non-zero runoff most of the time, and
the consecutive dry days (period) method that is better suited for areas
where zero runoff occurs. The newly presented method allows a drought in
periods with runoff to continue in the following period without runoff. The
method is demonstrated by identifying droughts from discharge observations
of four rivers situated within different climate regimes, as well as from
simulated runoff data at global scale obtained from an ensemble of five
different land surface models. The identified drought events obtained by the
new approach are compared to those resulting from application of the
variable threshold level method or the consecutive dry period method
separately. Results show that, in general, for drier regions, the threshold
level method overestimates drought duration, because zero runoff periods are
included in a drought, according to the definition used within this method.
The consecutive dry period method underestimates drought occurrence, since it
cannot identify droughts for periods with runoff. The developed method
especially shows its relevance in transitional areas, because, in wetter
regions, results are identical to the classical threshold level method. By
combining both methods, the new method is able to identify single drought
events that occur during positive and zero runoff periods, leading to a more
realistic global drought characterization, especially within drier
environments. |
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