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| Titel |
Early warning of drought in Europe using the monthly ensemble system from ECMWF |
| VerfasserIn |
C. Lavaysse, J. Vogt, F. Pappenberger |
| 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 ; 19, no. 7 ; Nr. 19, no. 7 (2015-07-28), S.3273-3286 |
| Datensatznummer |
250120771
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| Publikation (Nr.) |
 copernicus.org/hess-19-3273-2015.pdf |
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| Zusammenfassung |
Timely forecasts of the onset or possible evolution
of droughts are an important contribution to mitigate their manifold negative
effects. In this paper we therefore analyse and compare the performance of
the first month of the probabilistic extended range forecast and of the
seasonal forecast from the European Centre for Medium-range Weather
Forecasts (ECMWF) in predicting droughts over the European continent. The
Standardized Precipitation Index (SPI-1) is used to quantify the onset or
likely evolution of ongoing droughts for the next month.
It can be shown that on average the extended range forecast has greater skill
than the seasonal forecast, whilst both outperform climatology. No
significant spatial or temporal patterns can be observed, but the scores are
improved when focussing on large-scale droughts. In a second step we then
analyse several different methods to convert the probabilistic forecasts of
SPI into a Boolean drought warning. It can be demonstrated that methodologies
which convert low percentiles of the forecasted SPI cumulative distribution
function into warnings are superior in comparison with alternatives such as
the mean or the median of the ensemble. The paper demonstrates that up to
40 % of droughts are correctly forecasted one month in advance.
Nevertheless, during false alarms or misses, we did not find significant
differences in the distribution of the ensemble members that would allow for
a quantitative assessment of the uncertainty. |
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