学会誌「自然災害科学」

資料解析に基づく日本海沿岸での台風時波浪の極値の推定

Estimation of Extreme Values of Typhoon-Generated Waves in the Japan Sea Coasts Based on the Analysis of Measurement Data

山口 正隆*・畑田 佳男*・大福 学*・野中 浩一**

Masataka YAMAGUCHI*, Yoshio HATADA*, Manabu OHFUKU* and Hirokazu NONAKA**

Abstract

Return wave height and its standard deviation for typhoon-generated waves are estimated based on the statistical analysis of the measurement data with a period of 10 to 28 years at 19 coastal stations in the Japan Sea. An extreme-value analysis using the least squares method for the parameter estimation of the candidate distribution is applied. Similar evaluations for extreme-value data of waves generated by other types of meteorological disturbances such as low pressure systems and monsoons are conducted as well. Comparison among these estimates indicates that the high waves generated by low pressure systems and monsoons exercise a predominantly strong effect on the distribution of extreme heights in the Japan Sea coasts. The effect of typhoon-generated waves on extreme heights is found significant locally in the northeastern coasts, but the confidence interval of the return wave height is too great to yield a reliable estimate. Another finding is that the return wave height becomes greater in the northeastern coasts than in the southwestern coasts, irrespective of classification of meteorological disturbances which bring about high waves.

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