 |
| Titel |
A global evaluation of streamflow drought characteristics |
| VerfasserIn |
A. K. Fleig, L. M. Tallaksen, H. Hisdal, S. Demuth |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1027-5606
|
| Digitales Dokument |
URL |
| Erschienen |
In: Hydrology and Earth System Sciences ; 10, no. 4 ; Nr. 10, no. 4 (2006-07-21), S.535-552 |
| Datensatznummer |
250008140
|
| Publikation (Nr.) |
 copernicus.org/hess-10-535-2006.pdf |
|
|
|
|
|
| Zusammenfassung |
| How drought is characterised depends on the purpose and region of the study
and the available data. In case of regional applications or global
comparison a standardisation of the methodology to characterise drought is
preferable. In this study the threshold level method in combination with
three common pooling procedures is applied to daily streamflow series from a
wide range of hydrological regimes. Drought deficit characteristics, such as
drought duration and deficit volume, are derived, and the methods are
evaluated for their applicability for regional studies. Three different
pooling procedures are evaluated: the moving-average procedure
(MA-procedure), the inter-event time method (IT-method), and the sequent
peak algorithm (SPA). The MA-procedure proved to be a flexible approach for
the different series, and its parameter, the averaging interval, can easily
be optimised for each stream. However, it modifies the discharge series and
might introduce dependency between drought events. For the IT-method it
is more difficult to find an optimal value for its parameter, the length of
the excess period, in particular for flashy streams. The SPA can only be
recommended as pooling procedure for the selection of annual maximum series
of deficit characteristics and for very low threshold levels to ensure that
events occurring shortly after major events are recognized. Furthermore, a
frequency analysis of deficit volume and duration is conducted based on
partial duration series of drought events. According to extreme value
theory, excesses over a certain limit are Generalized Pareto (GP)
distributed. It was found that this model indeed performed better than or
equally to other distribution models. In general, the GP-model could be used
for streams of all regime types. However, for intermittent streams,
zero-flow periods should be treated as censored data. For catchments with
frost during the winter season, summer and winter droughts have to be
analysed separately. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|