Temporal variations in internal tide multimodal structure on the continental shelf, South China Sea  

作　　者：GAO Dalu JIN Guangzhen LU Xianqing 高大鲁;靳光震;吕咸青(Key Laboratory of Physical Oceanography (Ocean University of China), Ministry of Education;Key Lab of Marine Science and Numerical Modeling, First Institute of Oceanography, SOA)

机构地区：[1]Key Laboratory of Physical Oceanography （Ocean University of China）, Ministry of Education, Qingdao 266100, China [2]Key Lab of Marine Science and Numerical Modeling, First Institute of Oceanography, SOA, Qingdao 266061, China

出　　处：《Chinese Journal of Oceanology and Limnology》2017年第1期70-78,共9页中国海洋湖沼学报（英文版）

基　　金：Supported by the State Ministry of Science and Technology of China(Nos.2013AA122803,2013AA09A502);the National Natural Science Foundation of China(Nos.41206001,41371496);the Natural Science Foundation of Shandong Province of China(No.ZR2014DM017);National Key Technology Research and Development Program(No.2013BAK05B04)

摘　　要：Temporal variations in multimodal structures of diurnal( D_1) and semidiurnal( D_2) internal tides were investigated on the continental slope of the Dongsha Plateau, based on 2-month moored acoustic Doppler current profiler observations. Harmonic analysis indicated that the D_1 components( K_1 and O_1) dominated the internal tide field. The vertical structure of the K_1 constituent presented a first-mode structure while the M_2 constituent seemed to exhibit a high-mode structure. Amplitude spectra analysis of the current data revealed differences in baroclinic current amplitudes between different water depths. Temporal variations in modal structures ware analyzed, based on the D_1 and D_2 baroclinic tides extracted from the baroclinic velocity field with band-pass filters. Analysis showed that the magnitude of the D_1 internal tide current was much larger than the D_2 current, and temporal variations in the modal structure of the D_1 internal tide occurred on an approximately fortnightly cycle. The EOF analyses revealed temporal transformation of multimodal structures for D_1 and D_2 internal tides. The enhancement of the D_1 internal tide was mainly due to the superposition of K_1 and O_1, according to the temporal variation of coherent kinetic energy.Temporal variations in multimodal structures of diurnal（ D_1） and semidiurnal（ D_2） internal tides were investigated on the continental slope of the Dongsha Plateau, based on 2-month moored acoustic Doppler current profiler observations. Harmonic analysis indicated that the D_1 components（ K_1 and O_1） dominated the internal tide field. The vertical structure of the K_1 constituent presented a first-mode structure while the M_2 constituent seemed to exhibit a high-mode structure. Amplitude spectra analysis of the current data revealed differences in baroclinic current amplitudes between different water depths. Temporal variations in modal structures ware analyzed, based on the D_1 and D_2 baroclinic tides extracted from the baroclinic velocity field with band-pass filters. Analysis showed that the magnitude of the D_1 internal tide current was much larger than the D_2 current, and temporal variations in the modal structure of the D_1 internal tide occurred on an approximately fortnightly cycle. The EOF analyses revealed temporal transformation of multimodal structures for D_1 and D_2 internal tides. The enhancement of the D_1 internal tide was mainly due to the superposition of K_1 and O_1, according to the temporal variation of coherent kinetic energy.

关 键 词：internal tides South China Sea multimodal structure temporal variation 

分 类 号：P731.23[天文地球—海洋科学]