WIND SPEEDS AND WAVE HEIGHTS OF RARE RECURRENCE IN AZOV-BLACK SEA REGION OF UKRAINE

Estimation of extreme wind and wave parameters plays an important role in solving engineering tasks in coastal areas. This problem is of high current interest for the Azov and Black seas coastal zones of the Ukraine. In this paper wind speeds and wave heights of rare recurrence were estimated for the period of 1958?2012, based on data from maritime observational network of the Ukraine. Two probability functions, namely, Weibull function and bimodal Weibull mixture (BIW), were tested in terms of coefficient of determination, R 2, and mixing parameter, w.The BIW model gives larger R 2 than the Weibull function, generally due to better fit of the upper tail of empirical distributions. The BIW was shown to be more appropriate for statistical description of the wind speeds and wave heights of rare recurrence (less than 2 % level). The BIW function is a mixture of two Weibull-like components which make up the BIW bimodal function. Non-stationarity of the time series used in analysis was found to be the main reason of bimodality of the empirical probability function.