波浪

[II-79] Consideration of historical variation of extreme offshore wave condition and cargo handling operation rate based on long-term wave hindcasting

*平山 克也¹、濱野 有貴¹、森谷 拓実² (1. 港湾空港技術研究所、2. エコー)

Keywords:wave hindcasting, wave transformation, historical variation, annual-averaged wave, extreme offshore wave, cargo handling operation rate

The global climate change may affect both annual-averaged and extreme wave field. To consider this subject, a long-term hindcasting wave data for 34 years (1979-2012) at an offshore point of Minami and Kita Daito Islands is focused. Both the statistical analysis of extreme offshore waves per 5 years and the estimation of annual cargo handling operation rates of both islands are conducted. Because the reduction of both annual-averaged and extreme wave heights has appeared since 1998, it is supposed that the northern-east trade wind has got weak and no severe storms have approached in this area for 15 years. Reflecting this trend, the cargo handling operation rates of both islands tend to little increase.