WAVE GROUPING AND SEQUENTIAL CORRELATION, FIELD STUDIES IN ITALIAN COASTAL AREAS

Existing theories about wave grouping are compared; Kimura's theory is shown to fit experimental statistics closest. The statistics derived from records taken at five sites of the ENEL wave measuring network ar e compared favorably with the corresponding values predicted by Kimura 's theory. The discrepancy ratios are greater for greater depth sites and for low threshold values. They are however limited: the mean group length discrepancy is about 5% on the average, and less than 17% for the worst class. The divergence from Kimura theoretical scheme is show n to be due to the approximations necessary to reduce the analytical p roblem within the Markov processes sphere, the intrinsic difference be tween the wave height and twice the envelope amplitude, the variabilit y of actual wave periods and the bias of the statistics employed for r un length. Finally, the sequential correlation of wave characteristics is examined and the hypothesis that waves form a first order Markovia n process is tested.