Extreme waves in the Central Mediterranean Sea for design of offshore wind farms and wave energy devices

This paper is concerned with the analysis of extreme waves in the Mediterranean Sea, for the design of sea structures, including supports for offshore wind farms and wave energy devices. The input data are the significant wave heights Hs given by buoys data and by a numerical simulation performed on the Mediterranean Sea between 2001 and 2009, with a third generation ocean wave model. The extreme waves pertain to severe storms described by the Equivalent Power Storm (EPS) model, which represents any actual storm by means of two parameters. The former gives the storm intensity, and is equal to the maximum significant wave height during the actual storm; the latter represents the storm duration. The structure of the storms depends upon a power law, with a λ exponent: for λ =1 we have triangular storms (Boccotti, 2000; Arena & Pavone, 2006, 2009), for λ =2 parabolic storms, for λ =0.5 cusp storms and so on (Fedele and Arena, 2010). The EPS model is applied for calculating the return period of a sea storm in which the maximum significant wave height exceeds a fixed threshold. This analysis is proposed for some storms recorded in any considered location. Then, the significant wave height is calculated for several values of the return period. These values are required for the design of devices used as support of wind farms, or for production of electrical power from wave energy