Tides and waves in the Central Mediterranean Sea

Abstract

Meteo-marine data are necessary and useful for all tasks and scientific activities of national interest involving the protection, enhancement and improvement of the marine environment. The Institute for Environmental Protection and Research (ISPRA) maintains and manages two monitoring networks in order to gather all physical parameters needed in defining the state of Central Mediterranean Sea: the Sea Level Measurement Network (Rete Mareografica Nazionale, RMN) and the Sea Waves Measurement Network (Rete Ondametrica Nazionale, RON). The RMN includes 36 coastal measurement stations; real-time series of sea-level and meteorological parameters are collected every minute. Tide gauges mainly collect sea level, air and water temperatures, wind speed and direction and relative humidity. The RON consists of 15 real-time directional buoys uniformly distributed along the Italian coastline. They collect the main physical parameters such as significant and maximum wave height, peak and mean wave period, wave direction, sea surface temperature (SST), air temperature, wind speed and direction, atmospheric pressure and relative humidity. In this paper attention is focused on statistical analysis in order to describe wave climates, extreme events, tsunami, sea storms and storm surges and related meteorological information. The statistics taken into consideration are mainly the joint frequency distribution of significant wave heights with respect to direction and peak and mean wave periods. Extreme-event analysis is made through the peak over threshold (POT) method and the generalised Pareto distribution (GPD). Finally, sea-level time series analyses are used to highlight examples of meteorological events (such as tsunami) through harmonic and residual analysis.