【作者】 查国震；

【导师】 何宜军；

【作者基本信息】 中国科学院研究生院（海洋研究所） ， 物理海洋学， 2012， 博士

【摘要】 海洋内孤立波在世界各大洋中普遍存在。这些内孤立波携带着巨大的能量，可以在海洋内部传播几千公里。内孤立波也会诱发剧烈的垂向混合，对局地的海洋环境以及大尺度的大洋环流造成重要的影响。海洋中的大振幅内孤立波在传播过程中会诱发突发性强流，从而对海上石油平台等建筑造成危害。船载X波段雷达图像分辨率高，可以对海面进行连续观测，在海洋内孤立波研究中具有独到的优势，但是其相关的应用尚未引起足够的重视。针对以上一系列问题和船载X波段雷达的特点，本文在前人工作的基础上主要工作如下：(1)发展了一种基于连续分层海洋内孤立波模型的从船载X波段雷达和背景场浮力频率数据反演大振幅内孤立波振幅的方法：首先利用船载X波段雷达图像获得内孤立波的非线性速度；然后用多次测量的CTD (Conductivity-Temperature-Density，即温盐深仪)数据计算背景场的浮力频率数据，并对该数据进行低通滤波处理；最后利用Thomson-Haskell方法解内孤立波的本征方程，获得内孤立波的长波相速度，KdV方程(Korteweg de Vriesequantion)的非线性系数等参数，并估计大振幅内孤立波的振幅。(2)发展了一种基于船载X波段雷达和背景场浮力频率数据估算大振幅内孤立波对海上桩柱作用力的方法。首先通过船载X波段雷达图像获得内孤立波的非线性速度；在获得背景场浮力频率的基础上，利用Thomson-Haskell方法解内孤立波的本征方程，并确定内孤立波各个模态的本征函数、半振幅宽度和内波振幅等参数；接下来利用KdV方程的孤立子解和连续性方程计算内孤立波所诱发水平流场的流速和加速度；最后通过Morison经验公式计算大振幅内孤立波对海上桩柱的作用力和力矩。(3)计算并分析了中国南海东沙岛附近的内孤立波场所诱发的垂向热通量。中国南海东沙岛附近是海洋内孤立波的多发海域。这些内孤立波能够诱发剧烈的垂向混合，从而对局地海洋环境产生重要的影响。中国科学院海洋研究所2009年06月在南海东沙岛附近进行了连续25小时的内波观测实验。本文利用此次观测实验过程中采集的温度链、ADCP(Acoustic Doppler Current Profilers，即声学多普勒流速剖面仪)和CTD数据计算了该海域内孤立波场所诱发的垂向热通量。结果发现该海域的内孤立波场能够诱发剧烈的跨跃层热交换，其诱发的平均热通量可达400W/m2。更多还原

【Abstract】 Ocean internal solitons are ubiquitous in coastal oceans. These internal solitons carryenormous energy and can propagate hundreds of kilometers in the interior of the water. Oceaninternal solitons can also induce strong vertical mixing. Large amplitude ocean internal solitonsmay induce strong underwater currents and cause a severe threat to deep-sea oil and gas drillingrigs or pipelines. Nautical X-band radar is capable of scanning large areas of sea surface with ahigh temporal and spatial resolution and can be a powerful tool for the study of ocean internalsolitons. Considering these problems and the characteristics of nautical X-band radar, the maintasks of this paper are as follows:(1) Developed a method to retrieve amplitudes of large amplitude internal solitons fromnautical X-band radar observations and background buoyancy frequency profile. First, calculatethe mean profile of the buoyancy frequency from in-situ measurements, and process the datawith low pass filter. Second, solve Taylor-Golstein equation (eigenvalue problem) by using theThomson-Haskell method, and determine the nonlinear coefficient of KdV equation and phasespeed of linear long wave. Third, estimate the nonlinear velocity of internal solitons from marineradar images by a method based on the use of Radon Transform technique. With the aboveparameters, the soliton’s amplitude can be determined.(2) Proposed a method to estimate the force and torque exerted by an ocean internal solitonon an offshore vertical cylindrical pile based on traditional marine radar images and backgroundbuoyancy frequency data. On the basis of above work, the vertical profile of the horizontalvelocity induced by an ocean internal soliton and its acceleration can be determined. Finally, theforce and torque exerted by the internal soliton acting on a pile can be estimated by Morison’sempirical formula.(3) Calculated and analysis the vertical heat flux induced by ocean internal solitons in thevicinity of the northeastern continental slop of the Dongsha island in South China Sea. Oceaninternal solitons are ubiquitous in South China Sea, and can pose important impact on the local marine environment and global circulation. One day’s continuous observation was made from15:40on June24to16:40on June25by Conductivity-Temperature-Depth (CTD), thermistorchain and Acoustic Doppler Current Profiler (ADCP) as a part of the field investigation cruise ofthe Knowledge Innovation Project of the Chinese Academy of Sciences. The vertical heat fluxinduced by internal solitons was concentrated on thermocline and can reach400W/m2.更多还原