| 摘要: |
| 采用东沙岛附近的一个长达 9 个月的锚定潜标的观测资料对南海北部的正压潮、内潮和余流情况进行了分析, 得到了当地正压潮和内潮的特征。此处正压潮流以全日潮为主, 秋、冬季相对较大, 春季相对较小; 正压余流受海盆尺度环流和地形的限制, 在潜标观测期间的秋、冬、春三季基本以偏西向的正压流为主。内潮同正压潮一样, 也以全日分潮为主, 潮流椭圆随水深发生旋转, 在110—120 m 附近存在内潮非常弱的一层。斜压余流在 2009 年 2—3 月比较异常, 这是由于在此其间有一个中尺度涡经过。对此潜标数据采用经验正交函数分解的方法进行分析, 发现海流的各个主要EOF 模态与内波的垂向模态结构有一定的关联。 |
| 关键词: 南海, 东沙, 内潮, 经验正交函数 |
| DOI：10.11693/hyhz201201002002 |
| 分类号: |
| 基金项目:中国科学院重大项目, KZCX1-YW-12 号; 国家高技术研究发展计划 863 项目, 2008AA09A402 号 |
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| THE CHARACTERISTICS OF THE INTERNAL TIDES AND RESIDUAL TIDAL CURRENTS AROUND THE DONGSHA ISLAND IN THE NORTHERN SOUTH CHINA SEA |
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SI Guang-Cheng1,2, HOU Yi-Jun1
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1.Key Laboratory of Ocean Circulation and Waves, Institute of Oceanology, the Chinese Academy of Sciences;2.Graduate School, the Chinese Academy of Sciences
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| Abstract: |
| The characteristics of the barotropic tides, baroclinic tides and residual tidal currents were analyzed based on a 9-month current record from a mooring site near the Dongsha Island in the northern South China Sea. The barotropic tides were dominated by diurnal tides, which were much stronger in autumn and winter than in spring. Forced by the basin-scale circulation and the bottom topography, the barotropic residual currents were the strongest in winter and were mainly towards the west during the observation period. The baroclinic tides were also dominated by the diurnal tides. The tidal current ellipses rotated with depth and there was a layer at 110—120 m depth where the tidal currents were very weak. Compared to the sea level anomaly, the abnormality of residual currents in February and March of 2009 was due to the passage of a mesoscale eddy. Finally, the EOF analyses of the currents showed that the EOF modes were related to the mode structure of the internal wave. |
| Key words: South China Sea, Dongsha Island, internal tides, EOF |
