AN EVALUATION OF EXTREME WAVE CLIMATE AT KEAHOLE POINT, HAWAII

Abstract

An evaluation of extreme wave climate was made for Keahole Point, Hawaii. This evaluation was based on three separate sources of wave data and five methods of statistical evaluations. The three sources of data include (1) wave hindcasts data of 10 severe storms between 1947- 1961 by Marine Advisors (1963), (2) wave hindcast data of 11 severe storms between 1947-1965 by U.S. Army Corps of Engineers, Honolulu District, and (3) shipboard wave observations of the U.S. Navy reports. Figure 5 shows SSMO area No. 1 for south and southwest of the islands and SSMO areas Nos. 2 and 3 for north of the islands. The five methods of statistical extrapolations for extreme events include: (1) Gumbel's (1958) first asymptotic distribution, (2) Weibull distribution (1961), and (3,4,&5) semilog, log normal and normal distributions. The three most widely used distribution functions are: (1) Gumbel's (1958), (2) log normal (see Jasper, 1956), and (3) Weibull (1961), given in order as to the author's preference. The statistical extrapolations for Keahole Point, Hawaii, are given in Table 9 and Figure 9. Only Gumbel's (1958) distribution was applied to the north shore as shown in Table 8. Based on Gumbel's distribution function, the results of the wave hindcasts statistics on the average (50 year recurrence interval) indicate that (1) the Marine Advisors (1963) wave hindcasts are about 25 percent higher than the U.S. Army Corps of Engineers wave hindcasts and (2) the U.S. Navy SSMO observations and the U.S. Army Corps of Engineers wave hindcasts are in closest agreement. Shipboard wave observations have always been subjected to questions. However, various authors have correlated instrumentally measured and observed wave observations. A summary of these correlations are given in Table 6. No correction was made to the statistical analysis of the SSMO data.