Jasper Hoek

Depending on the geographical region, TCs can either be a regular phenomenon which occurs on average multiple times per year, or a rare event which might occur once every year or once every few years. In both cases these events are usually responsible for extreme wave and storm surge conditions if they pass by or make landfall close enough the the Area of Interest (AoI). Based on historical data alone, predictions for design storm conditions are inaccurate in most areas because of data scarcity caused by the relatively infrequent occurrence of cyclones affecting a specific city or coastal stretch, and by the difficulty to obtain reliable wave data because of the severe weather conditions. Also, the exact track, intensity and size of the storm are very determining for the exact area which is affected and for what the consequences are for the hydraulic conditions. Small variations in any of these parameters can greatly influence the storm surge and wave conditions at the AoI. To deal with this data scarcity problem and the fact that small changes in the track of the cyclones can cause great variability in damages, the current trend is to try to generate synthetic cyclones to increase the amount of data by looking at the possible cyclones that could occur in the future.

So far the general focus for the hydraulic conditions caused by tropical cyclones is on determining design storm surge levels which are used in risk assessment studies for insurance companies. Up to now very little research has been done to determine design wave conditions. Possible explanations for this are the larger required computational effort for modelling waves and the smaller probability of causing floods than storm surge. Nevertheless design wave conditions are of utmost importance for coastal erosion studies, the design of coastal defence structures and risk assessment of the hinterlands.

This study aims to develop a feasible method to determine design wave conditions in regions with rare cyclone events.

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