Abstract The aim of the present work is to give a significant aid to maritime and offshore designers who operate in the Mediterranean Sea. Ten years of wave data, collected from 8 buoys of the SWaN (Sea Wave measurement Network - National Hydrological and Marine Survey or, in Italian, RON Rete Ondametrica Nazionale, Servizio ldrografico e Mareografico Nazionale), are analysed by means of the standard statistical methods recommended by the 1AHR - Working Group on extreme wave statistics. Climatological wave analyses are presented for the stations of La Spezia, Alghero, Ponza, Mazara (Tyrrenian Sea), Monopoli, Ortona (Adriatic Sea), Crotone and Catania (Ionian Sea). Main and secondary sectors, related to the directions of maximum observed significant waves, are bounded Hypothesis of data independence and stationarity are discussed," independent episodes are extracted from the 10 years long RON database in connection with the main Italian wave climatological features. The Weibull distribution function is fitted to data for all the main sectors. Statistical models are applied in order to obtain return values of significant wave heights corresponding to return periods ranging from 5 up to 50 years. Results are discussed and, in order to test the robustness of the analysis, return values for the 5 years return period are compared with the second observed maxima. Correlation between the standard error of the distribution estimate, obtained by means of Least Squares Method and the overall number of missing data, is shown and discussed.
THE SEA WAVE MEASUREMENT NETWORK The Sea Wave Measurement Network (Swan), Rete Ondametrica Nazionale (ICON) in Italian language, operates since July 1989. The Swan data were supplied by the National Hydrological and Marine Survey to public and private bodies that used them in the maritime structure design, into climate studies, into wave-forecast analyses and validation.