This paper analyses the trends and the future projections of significant wave height in several ocean areas at different parts of the world. It uses a stochastic Bayesian hierarchical space-time model, with a regression component with atmospheric levels of CO2 as covariates in order to estimate the expected long-term trends and make future projections towards the year 2100. The model was initially developed for an area in the North Atlantic ocean, and has been found to perform reasonably well there, and it is now investigated how the model performs for other ocean areas. 11 new ocean areas have been analysed with the model, and this paper presents the results pertaining to the estimated long-term trends and future projections of monthly maximum significant wave height for each of the 12 ocean areas.
The ocean wave climate is obviously important to maritime safety, as well as many other areas of society. Ships and other marine and coastal structures are designed in order to withstand normal and extreme environmental loads imposed by the forces of wind and waves at sea. However, the potential impact of climate change on the ocean wave climate is often neglected, and it is also a lack of knowledge on how the future ocean wave climate will change as a result of climate change. Recently, a Bayesian hierarchical space-time model was developed to investigate long-term trends and make future projections of the ocean wave climate for an area in the North Atlantic ocean. Results from the initial model are reported in Vanem et al. (2012a), results from a revised model with a logarithmic transformation of the data are reported in Vanem et al. (2012b) and results from an extended model with a regression component on atmospheric levels of CO2 are reported in Vanem et al. (2012c).