Journal cover Journal topic
Natural Hazards and Earth System Sciences An interactive open-access journal of the European Geosciences Union
Nat. Hazards Earth Syst. Sci., 16, 255-268, 2016
© Author(s) 2016. This work is distributed under
the Creative Commons Attribution 3.0 License.
Research article
25 Jan 2016
An approach to build an event set of European windstorms based on ECMWF EPS
R. Osinski2,1, P. Lorenz3,1, T. Kruschke4,1, M. Voigt5,1, U. Ulbrich1, G. C. Leckebusch6,1, E. Faust7, T. Hofherr7, and D. Majewski8 1Institute of Meteorology, Freie Universität Berlin, Berlin, Germany
2CNRM/GAME, Météo-France and CNRS, Toulouse, France
3Meteo Service Weather Research GmbH, Berlin, Germany
4GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
5GFZ German Research Centre for Geosciences, Potsdam, Germany
6School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham, UK
7Munich Re, Munich, Germany
8German Weather Service, Offenbach, Germany
Abstract. The properties of European windstorms under present climate conditions are estimated on the basis of surface wind forecasts from the European Centre for Medium-Range Weather Forecast (ECMWF) Ensemble Prediction System (EPS). While the EPS is designed to provide forecast information of the range of possible weather developments starting from the observed state of weather, we use its archive in a climatological context. It provides a large number of modifications of observed storm events and includes storms that did not occur in reality. Thus it is possible to create a large sample of storm events, which entirely originate from a physically consistent model, whose ensemble spread represents feasible alternative storm realizations of the covered period. This paper shows that the huge amount of identifiable events in the EPS is applicable to reduce uncertainties in a wide range of fields of research focusing on winter storms. Windstorms are identified and tracked in this study over their lifetime using an algorithm based on the local exceedance of the 98th percentile of instantaneous 10 m wind speed, which is associated with a storm severity measure. After removing inhomogeneities in the data set arising from major modifications of the operational system, the distributions of storm severity, storm size, and storm duration are computed. The overall principal properties of the homogenized EPS storm data set are in good agreement with storms from the ERA-Interim data set, making it suitable for climatological investigations of these extreme events. A demonstrated benefit in the climatological context by the EPS is presented. It gives clear evidence of a linear increase of maximum storm intensity and wind field size with storm duration. This relation is not recognizable from a sparse ERA-Interim sample for long-lasting events, as the number of events in the reanalysis is not sufficient to represent these characteristics.

Citation: Osinski, R., Lorenz, P., Kruschke, T., Voigt, M., Ulbrich, U., Leckebusch, G. C., Faust, E., Hofherr, T., and Majewski, D.: An approach to build an event set of European windstorms based on ECMWF EPS, Nat. Hazards Earth Syst. Sci., 16, 255-268,, 2016.
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