On the Long-term Changes of Extreme Wave Heights at the German Baltic Sea Coast

Xu, Z.S.; Dreier, N.; Chen, Y.P., Fröhle, P. and Xie, D.M., 2016. On the long-term changes of extreme wave heights at the German Baltic Sea Coast. In: Vila-Concejo, A.; Bruce, E.; Kennedy, D.M., and McCarroll, R.J. (eds.), Proceedings of the 14th International Coastal Symposium (Sydney, Australia). Journal of Coastal Research, Special Issue, No. 75, pp. 962–966. Coconut Creek (Florida), ISSN 0749-0208. The assessment of extreme wave heights is of great importance for the design of coastal protection strucutres. This paper aims to present long-term changes of extreme wave heights at several selected locations at the German Baltic Sea Coast. Annual maximum significant wave heights were selected from the hourly wave data obtained from a hybrid approach (wind-wave-correlations combined with numerical simulations on the basis of the SWAN model) for a total period of 140 years, spanning from 1961 to 2100. The future projections of wind data were dreived from the regional COSMO-Climate Local Model for two emission scenarios A1B and B1. The extreme wave heights at each location were estimated from the respective best-fitting distribution, log-normal or Weibull distribution. The results indicate that, the long-term changes of extreme wave heights are related to the emission scenarios used in the regional climate model, the distribution chosen for the estimating (up to +9.6%) and also the sample size for the extreme value analysis (up to +8.7%). These factors should be carefully considered in the future coastal structure design.