摘要
内孤立波是存在于层结海洋内部的非线性、大振幅波动,其强劲的垂向和水平运动以及破碎导致的涡旋和湍流作用,对海洋环境、海底沉积物和海洋工程产生重要的影响。围绕内孤立波作用下沉积物再悬浮的发生过程,对前人开展的大量研究工作及取得的研究成果进行了系统分析与总结,从内孤立波向岸传播的破碎机制、悬浮沉积物模式以及引起的海床动力响应进行评述,并分析内孤立波悬浮沉积物判定理论和对海底的作用,对目前研究工作中尚未解决的问题进行总结。该工作对于系统深入认识内孤立波引起的海底沉积物再悬浮发生过程,以及对海底底形的改造能力具有重要价值,为进一步研究内孤立波对海洋生态环境动力过程及深海沉积过程提供借鉴。
Internal Solitary Waves (ISWs) are nonlinear, large amplitude motions of the interface between two fluids with different densities in the stratified ocean. Because of their strong vertical and horizontal current velocity, and the vortex, turbulent mixing caused by breaking, they affect marine environment, seabed sediment and man- made structures in the ocean. In the paper, we systematically analyzed and summarized the lSW-induced shoaling break mechanisms, models of suspension, and seabed dynamical response. Then, we discussed the ISW-induced sediment resuspension criteria, forming bottom and intermediate nepheloid layer and the capacity to suspend sedi- ments in the seabed, and further put forward the unsolved problems based on the conducted work and related a- chievements. In shallow seas with complex terrain variations, shoaling can cause ISWs to deform, break, and split. Studies on the propagation of ISWs of depression over sloping topography have shown that an adverse pressure gradi- ent causes the rotation of the flow separation, which produces vortices, and this results in global instability of the boundary layer and ISW burst. The separation vortices increase the bottom shear stress, vertical velocity, and near- bottom Reynolds stress, which leads to sediment resuspension and transport in the flow and vortex core. Although episodic, ISW-induced resuspension is hypothesized to be important enough to shape the topography. Shoaling ISWs may erode, resuspend and transport mud-like sediments, first towards shore by boluses, and subsequently offshore through the generation of intermediate nepheloid layers. Shoaling ISWs might be an important mechanism of muddy sediment dispersal along continental shelves. Furthermore, recent hypotheses suggest that sediment mobilization and transport caused by internal waves in general, and ISWs in particular, may be at the origin of some sedimentary structures found in the sedimentary rock record and also the hummocky-cross stratification. Observed on-shelf propa- gating frontal ISW most likely interacts with the sand waves, sediment waves or sand dunes. ISWs contribute to their generation, as they are trailed by considerable shear-induced turbulence and high-frequency internal waves close to the buoyancy frequency. This work is of great value for further understanding the process of ISW-induced sediment resuspension, transportation, and the capacity to suspend sediments in the seabed. It helps further study of the dynamic process of marine ecological environment dynamic process by 1SW and the deep sea sedimentation process.
作者
田壮才
郭秀军
余乐
贾永刚
张少同
乔路正
Tian Zhuangcai;Guo Xiujun;Yu Le;Jia Yonggang;Zhang Shaotong;Qiao Luzheng(Shandong Provincial Key Laboratory of Marine Environment and Geological Engineering, Ocean University of China, Qingdao Shandong 266100, China;Laboratory for Marine Geology, Qingdao National Laboratory for Marine Science and Technology, Qingdao Shandong 266061, China;Key Laboratory of Marine Environment & Ecology, Ministry of Education, Qingdao Shandong 266100, China;Shandong Province Urban and Rural Construction Investigation and Design Institute, Ji' nan 250031, China)
出处
《地球科学进展》
CAS
CSCD
北大核心
2018年第2期166-178,共13页
Advances in Earth Science
基金
国家自然科学基金重大科研仪器研制项目"复杂深海工程地质原位长期观测设备研制"(编号:41427803)
国家自然科学基金项目"近海浅层气电阻率成像法探测技术研究"(编号:41772307)资助~~
关键词
内孤立波
破碎机制
沉积物
动力响应
再悬浮
Internal solitary waves
Shoaling break
Sediiflent
Dynamical response
Resuspension.