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We consider a spatial stochastic model for the simulation of tropical cyclone tracks, which has recently been introduced. Cyclone tracks are represented as labeled polygonal lines, which are described by the movement directions, translational speeds, and wind speeds of the cyclones in regular 6-h intervals. In the present paper, we compare return levels for wind speeds of historically observed cyclone tracks with those generated by the simulator, where a mismatch is shown for most of the considered coastal regions. To adjust this discrepancy, we develop a stochastic algorithm for acceptance and rejection of simulated cyclone tracks with landfall. It is based on the fact that the locations, translational speeds, and wind speeds of cyclones at landfall constitute three-dimensional Poisson point processes, which are a basic model type in stochastic geometry. Due to that, a well-known thinning property of Poisson processes can be applied. This means that to each simulated cyclone, an acceptance probability is assigned, which is higher for cyclones with suitable landfall characteristics and lower for implausible ones. More intuitively, the algorithm comprises the simulation of a more comprehensive cyclone event set than needed and the random selection of those tracks that best match historical observations at landfall. A particular advantage of our algorithm is its applicability to multiple landfalls, i.e., to cyclones that successively make landfall at two geographically distinct coastlines, which is the most relevant case in applications. It turns out that the extended simulator provides a much better accordance between landfall characteristics of historical and simulated cyclone tracks. 相似文献
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G. Grünthal A. H. Thieken J. Schwarz K. S. Radtke A. Smolka B. Merz 《Natural Hazards》2006,38(1-2):21-44
In this paper a methodology for a multi-risk assessment of an urban area is introduced and performed for the city of Cologne,
Germany, considering the natural hazards windstorm, flooding and earthquake. Moreover, sources of the uncertainty in the analysis
and future needs for research are identified. For each peril the following analyses were undertaken: hazard assessment, vulnerability
assessment and estimation of losses. To compare the three hazard types on a consistent basis, a common economic assessment
of exposed assets was developed. This was used to calculate direct economic losses to buildings and their contents. The perils
were compared by risk curves showing the exceedence probability of the estimated losses. In Cologne, most of the losses that
occur frequently are due to floods and windstorms. For lower return periods (10–200 years) the risk is dominated by floods.
For return periods of more than 200 years the highest damage is caused by earthquakes. 相似文献
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