Seasonal characteristics of internal tides and their responses to background currents in the Luzon Strait

作     者：FANG Yong HOU Yijun JING Zhiyou 

作者机构：State Key Laboratory of Tropical Oceanography (LTO) South China Sea Institute of Oceanology Chinese Academy of Sciences Key Laboratory of Ocean Circulation and Waves (KLOCAW) Institute of Oceanology Chinese Academy of Sciences 

出 版 物：《Acta Oceanologica Sinica》 (海洋学报（英文版）)

年 卷 期：2015年第34卷第11期

页      面：46-54页

核心收录：

学科分类：07[理学] 0707[理学-海洋科学] 

基　　金：The National Natural Science Foundation of China under contract Nos 41276022,U1133001,41230962,41206010 and 41206008 the Open Fund of the Key Laboratory of Ocean Circulation and Waves,Chinese Academy of Sciences under contract No.KLOCW1506 Guangdong Province Key Laboratory for Coastal Ocean Variation and Disaster Prediction Technologies,Guangdong Ocean University under contract No.GLOD1401 

主　　题：internal tide seasonal variation background current Luzon Strait 

摘      要：The spatial-temporal characteristics of internal tides （ITs） in the southwest Luzon Strait are examined, based on 9-month mooring current records from autumn 2008 to summer 2009. The results of spectral analysis show that the ITs in diurnal and semidiurnal frequencies are prominent at the mooring site, especially for the clockwise rotary component. The diurnal ITs are mostly dominated by the first mode except for that in spring when the second mode is relatively predominant. The semidiurnal ITs display a variable multimodal structure. Moreover, an apparent difference is detected in the kinetic energy of diurnal ITs. The energy is strongest in winter, and followed by that in summer, whereas the value is smallest in spring and autumn. It is suggested that the incoherent motions are responsible for the significant seasonal variations of diurnal ITs, reflecting interaction between diurnal ITs and the varying background conditions. However, the semidiumal ITs are independent of seasonal change, whose energy is smaller and only one-third of the diurnal energy in winter. Nevertheless, the abnormal variations of semidiurnal ITs are also related to the variable background conditions. The incoherent semidiurnal constituent accounts for about 37% of the total semidiurnal tidal kinetic energy, but the diurnal tidal motions contain fewer incoherent component （22.2%）.