Laboratorial and In-situ Data analyses on the Relationship between Internal Solitary Wave and Sea Surface Wave Spectrum

• Main Authors: Yun-Huan Yang, 楊昀桓
• Other Authors: Guan-Yu Chen
• Format: Others
• Language: zh-TW
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/64299264321765810244

碩士 === 國立中山大學 === 海下科技暨應用海洋物理研究所 === 102 === Wave spectrum is a measure of energy distribution for wave trains of all periods and directions. The shape of wave spectrum is affected by sea surface flow; hence, spectrum can be used to analyze the disturbance on the free surface. Previous studies showed that the sea bottom topography affects the flow and induces uneven distribution of the flow field when an internal wave passes a sill. Convergence of sea surface current enhances the convergence of surface wave, thus increases surface roughness and makes surface waves break. This study includes the radiation stress of deepwater wave theory. Physical experiments and field investigation in the northern South China Sea are used to analyze the spectrum change due to the change of flow velocity. One theory depends on the mean flow due to internal waves. The other theory of spectral variation depends on the gradient of flow velocity due to internal waves. The former theory implies the spectrum peak in the front part of the internal wave moves to the range of higher wavenumber .The in-situ spectrum observed by radar also shows the same tendency. Therefore, the former theory is more applicable than the later theory.