Extremes and resource assessment of wind and waves in central Mediterranean Sea

This paper deals with extremes and resource assessment of wind and waves in central Mediterranean Sea. The extreme value analysis is performed following Equivalent Storm Models (ESMs) approach, commonly employed in the context of significant wave height return values estimation. In this work, it is extended to wind storm events thanks to some analogies between wave and wind processes at short and long-term scale. The Equivalent Exponential Storm (EES) Model is selected for this study because of its realistic description of actual events time evolution. Energy estimations are based on both real storm data and EES model. The input data used for this analysis comes from the re-analysis of atmospheric and wave conditions performed by MeteOcean group at DICCA of Genoa University and cover the period from January 1979 to December 2020. Sixteen points have been selected including the south and west coast of the Italian peninsula, the Sicily and Sardinia Islands. The study is focused on return values estimation and energy assessment, mainly related on the storm concept; it aims to elucidate analogies and/or differences of wind and wave at a given site as well as how the two resources are distributed along the examined locations, identifying the potential working time over the year and which are the storm events providing the prevalent energetic contribution to harvestable energy. Results show that the location characterized by the severest wind storm and wave storm events do not coincide and not always the location where the severest storm occur is also the most energetic site. Further, the variability of return values with different levels of return period for wind speeds is lower than for significant wave heights: this aspect is moti-vated by a shape parameter of Weibull distribution that is systematically higher for the wind speed with respect to the significant wave height. The extremes of significant wave height are more variable from one location to another than those of wind speed ones and the same behavior is exhibited by energy resources, elucidating that the wind resource in the investigated sites is more homogeneous.