一个典型南海北部第二模态内孤立波的观测分析

钱洪宝; 黄晓冬; 田纪伟

doi:10.3969/j.issn.0253-4193.2016.09.002

一个典型南海北部第二模态内孤立波的观测分析

doi: 10.3969/j.issn.0253-4193.2016.09.002

1.
中国海洋大学物理海洋教育部重点实验室, 山东青岛 266100;中国21世纪议程管理中心, 北京 100038
2.
中国海洋大学物理海洋教育部重点实验室, 山东青岛 266100

基金项目: 南海关键岛屿周边多尺度海洋动力过程研究（2014CB745003）；内波与混合精细化观测系统集成与示范（2013AA09A502）；国家自然科学基金-南海北部内孤立波的季节与年际变化特征及影响机制（41506011）；广东省近海海洋变化与灾害预警重点实验室（GLOD）开放课题（GLOD1403）；青岛博士后应用研究项目。

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出版历程
- 收稿日期: 2016-04-26
- 修回日期: 2016-05-13

Observational study of one prototypical mode-2 internal solitary waves in the northern South China Sea

1.
Key Laboratory of Physical Oceanography, Ministry of Education, Ocean University of China, Qingdao 266100, China;The Administrative Center for China's Agenda 21, Beijing 100089, China
2.
Key Laboratory of Physical Oceanography, Ministry of Education, Ocean University of China, Qingdao 266100, China

摘要

摘要: 第二模态内孤立波在海洋中极少被观测到。本文基于潜标高时空分辨率观测数据，对南海北部陆架区的一个典型第二模态内孤立波进行了分析。结果表明，该第二模态内孤立波的流核出现在135 m深度处，其最大水平流速为0.66 m/s，传播方向为西偏北58°。沿传播方向的内孤立波流速分布在80～170 m的深度范围内，而与传播方向相反的逆流出现在海表和海底附近。垂向模态分析表明，该第二模态内孤立波水平流速的垂向结构与理论结果吻合良好。能量计算结果显示其动能密度的垂向积分可达14 kJ/m²，而波峰线方向单位长度上的动能估算值为5.98 MJ/m。尽管该第二模态内孤立波的动能比陆架区第一模态内孤立波小1个量级，但其高达0.045 s^-1的流速垂向剪切约为典型第一模态内孤立波的2倍，表明其导致的混合可能更强。
- 内孤立波 /
- 第二模态 /
- 潜标 /
- 观测 /
- 南海
Abstract: Mode-2 internal solitary wave (ISW) is seldom observed in real oceans. In this study, the characteristics of one prototypical mode-2 ISW over the continental shelf of northern South China (SCS) were analyzed, by using of mooring measurements with fine spatial and temporal resolutions. It was shown that the current core of mode-2 ISW appeared at a depth of 135 m, with a maximum of 0.66 m/s. The currents along the ISW propagation direction covered a depth range of 80~170 m, and the currents at a reverse direction were observed near the surface and bottom. Vertical mode analysis revealed that observed vertical structure of horizontal current of ISWs matched well with the theoretical results. At the trough of mode-2 ISW, the depth-integrated horizontal kinetic energy (KE) density could reach 14 kJ/m². Along the wave front, the KE of mode-2 ISW was up to 5.98 MJ/m. Although the kinetic energy of the mode-2 ISW was one order smaller than that of strong mode-1 ISW, its current shear of up to 0.045 s^-1 was two times as strong as that of mode-1 ISW, which suggested a more rapid energy dissipation.
- internal solitary wave /
- mode-2 /
- mooring /
- observation /
- South China Sea

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