Title: Modelling economic losses of historic and present-day high-impact winter windstorms in Switzerland

Abstract

This study investigates the wind gusts and associated economic loss patterns of high-impact winter windstorms in Switzerland between 1871 and 2011. A novel approach for simulating windstorm-related gusts and losses at regional to local scales is applied to a sample of 84 windstorms. The approach involves the dynamical downscaling of the Twentieth Century Reanalysis (20CR) ensemble mean to 3-km horizontal grid size using the Weather Research and Forecasting (WRF) model. Economic losses are simulated at municipal level for present-day asset distribution based on the downscaled (parameterised) wind gusts at high spatiotemporal resolution using the open-source impact model climada. A comparison with insurance loss data for two recent windstorms (“Lothar” in 1999, “Joachim” in 2011) indicates that the loss simulation allows to realistically simulate the spatial patterns of windstorm losses. The loss amplitude is strongly underestimated for ‘Lothar’, while it is in reasonable agreement for ‘Joachim’. Possible reasons are discussed. Uncertainties concerning the loss simulation arise from the wind gust estimation method applied; estimates can differ considerably among the different methods, in particular over high orography. Furthermore, the quality of the loss simulation is affected by the underlying simplified assumptions regarding the distribution of assets and their susceptibilities to damage. Formore » the whole windstorm sample, composite averages of simulated wind gust speed and loss are computed. Both composites reveal high values for the densely populated Swiss Plateau and lower values for south-eastern Switzerland; metropolitan areas stand out in the loss composite. Eight of the top 10 events concerning the losses simulated for present-day asset distribution and summed over all Swiss municipalities occurred after 1950. It remains uncertain whether this is due to decadal-scale changes of winter windstorms in Switzerland or merely due to a possible bias of the 20CR ensemble mean towards lower wind speeds in the period before around 1950.« less

Authors:

Welker, Christoph ^[1]; Martius, Olivia ^[2]; Stucki, Peter ^[2]; Bresch, David ^[3]; Dierer, Silke ^[4]; Brönnimann, Stefan ^[2]

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+ Show Author Affiliations

1. Univ. of Bern (Switzerland). Oeschger Centre for Climate Change Research, and Inst. of Geography; GVZ Gebaüdeversicherung Kanton, Zürich (Switzerland)
2. Univ. of Bern (Switzerland). Oeschger Centre for Climate Change Research, and Inst. of Geography
3. Swiss Reinsurance Company, Zurich (Switzerland)
4. Meteotest, Bern (Switzerland)

Publication Date:

Wed Mar 30 00:00:00 EDT 2016

Research Org.:

Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States). Oak Ridge Leadership Computing Facility (OLCF)

Sponsoring Org.:

USDOE Office of Science (SC), Innovative and Novel Computational Impact on Theory and Experiment (INCITE) Program; USDOE Office of Science (SC), Biological and Environmental Research (BER)

OSTI Identifier:

1565528

Resource Type:

Accepted Manuscript

Journal Name:

Tellus. Series A, Dynamic Meteorology and Oceanography (Online)

Additional Journal Information:

Journal Name: Tellus. Series A, Dynamic Meteorology and Oceanography (Online); Journal Volume: 68; Journal Issue: 1; Journal ID: ISSN 1600-0870

Publisher:

International Meteorological Inst.

Country of Publication:

United States

Language:

English

Subject:

54 ENVIRONMENTAL SCIENCES; meteorology & atmospheric sciences; oceanography; mid-latitude winter storms; impact modelling; risk assessment; 20CR; WRF; dynamical downscaling; wind gust estimation