Observational study to determine the causes of the freak wave generation in the open ocean

为了了解异常海浪的产生机制，利用现有的系泊在深海(~5400米)的浮标和漂流浮标开发了GPS海浪观测系统。经过一年多的观测，日本附近首次观测到波高超过13米的反常海浪和18米左右的巨浪。在这些观测证据的基础上，我们验证了异常海洋指数，并分析了日本附近的海上事故案例。此外，我们还对浮标的风资料进行了分析，发现在某些情况下，阵风事件与异常海洋事件同时发生，这是可能的海-气相互作用中的一个新发现。

To understand the freak wave generation mechanism, GPS wave observation systems utilizing an existing buoy moored in a deep ocean (~5400 m) and a drifting buoy were developed. Freak waves exceeding 13 m in wave height and giant waves around 18 m were observed near Japan, over a yearlong observations, for the first time in this region. Based on these observational evidences, we have validated the freakish sea index and analyzed marine accident cases near Japan. In addition, we have analyzed the wind data from the buoy and discovered that for certain cases the wind gust events occur concurrently with the freakish sea event, which is a new finding in the possible air-sea interaction.