近惯性内波的实验研究

项目名称： 近惯性内波的实验研究

项目编号： No.41476001

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 天文学、地球科学

项目作者： 陈旭

作者单位： 中国海洋大学

项目金额： 95万元

中文摘要： 海洋中的内波携带着动能，并存在小的垂向尺度和大的垂向剪切，因此对海洋混合和能量传输起着重要作用。部分研究估算表明混合层中由近惯性运动所做的功为0.3－1.4TW，与维持大洋深海层结需要的2TW相当，甚至高于正压潮向内潮的转化，证明了它在深海混合中的重要作用。 本项目希望通过实验室模拟的方法研究近惯性内波的产生与传播特征。在旋转层化流体表面利用扰动源产生扰动，利用断面流场测量技术及数字纹影技术分别测量近惯性内波引起的流场及密度场，定量测量其能量的传递。 实验内容包括i） 旋转的影响：不同Rossby数下的惯性运动； ii）层结的变化：从无分层到线性分层，最后跃层型密度分布； iii)扰动源：从二维平面波扰动源到三维点源。 通过此系列实验研究揭示海表扰动源生成的近惯性内波的机理，给出近惯性内波的垂向结构及传播特征，定量测量海面扰动到近惯性内波传播过程中的能量传输,这对海洋波谱的讨论十分重要。

中文关键词： 海洋内波；内波实验；近惯性内波；旋转实验；粒子图像测速技术

英文摘要： Internal waves carry a substantial fraction of kinetic energy in the ocean and have small vertical scales but large vertical shears. Therefore, internal waves play a crucial role in vertical mixing and energy transport in the ocean. Previous research suggests that the work done on near-inertial motions in the mixed layer by the wind is as large as 0.3-1.4 TW, comparable to the energy needed to maintain the abyssal stratification which is about 2 TW. It is even greater than the energy involved in the conversion from the barotropic tide to internal tide. All these proved the importance of near-inertial motions in the mixing of the deep ocean. This research project will focus on understanding of the physical processes that govern the generation and evolution of inertial internal waves by laboratory modeling method. The inertial internal waves will be generated by applying different perturbations on the surface of a rotating and stratified fluid. The fluid density and velocity field will be measured by 'synthetic schlieren' method and 'PIV' method, respectively. The transportation of energy will also be quantatively measured. The experiment is designed to: i) To study the effect of rotation: inertial motions with different Rossby number. ii) To study the effect of density stratification: first with homogeneous fluid, then linear stratification, and then stratification with a thermocline. iii) To compare different disturbance sources: 2-D plane waves and 3-D point source. The aim of this research project is to acquire a better understanding of the dynamic processes involved in the generation of inertial internal waves by sea surface disturbances and study the vertical structure and propagation of the generated inertial internal waves, which is very important in the study of oceanic wave spectrum.

英文关键词： internal waves;experiment of internal waves;near-inertial internal waves;experiment in a rotating fluid;PIV