Statistical Structure of the Global Significant Wave Heights

Significant wave height (SWH) observations from merged satellite (Jason-1, Jason-2, ENVISAT, …) data from 11 December 2005 to 20 July 2009 are used to investigate SWH statistical structure. The probability distribution of SWHs approximately satisfies the Weibull distribution. The statistical structure of SWHs is considered, both in terms of the leading-order moments (mean, standard deviation, skewness, and kurtosis) and in terms of the parameters of a best-fit Weibull distribution. In particular, it is found that the skewness of the SWH is a concave upward function of the ratio of the mean current speed to its standard deviation, such that the skewness is positive where the ratio is relatively small, the skewness is close to zero where the ratio is intermediate, and the skewness is negative where the ratio is relatively large. In addition, temporal evolutions of the probability distribution of SWHs are characterized. Furthermore, application to the wave prediction is also provided.