南海东北部海洋内波的反射地震研究  

Studying of oceanic internal wave spectra in the Northeast South China Sea from seismic reflections

作　　者：董崇志[1,2] 宋海斌[1] 郝天珧[1] 陈林[1,2] 宋洋[1,2] 

机构地区：[1]中国科学院地质与地球物理研究所,中国科学院油气资源研究重点实验室,北京100029 [2]中国科学院研究生院,北京100049

出　　处：《地球物理学报》2009年第8期2050-2055,共6页Chinese Journal of Geophysics

基　　金：国家基础研究发展规划项目(2007CB411704);欧盟项目(FP6-2003-NEST15603)资助

摘　　要：已有的内波研究多来自单点的垂直剖面观测资料,但研究内波水平特征的实测资料却非常缺乏.利用反射地震方法研究海水温盐结构,具有高水平分辨率和短时间内对整个海水垂直剖面进行成像的优势,能够弥补传统物理海洋学观测方法的缺陷,为研究海洋内波提供有前景的新手段.本文通过对南海东北部地震剖面的重新处理、分析,认为地震叠加剖面上同相轴呈现的起伏变化反映了内波的总体形态.计算的水平波数能量密度谱与GM76模型谱基本一致,但在低波数段和高波数段中,两者的振幅及斜率存在着一定差异,经分析认为这种差异主要与内潮波和复杂海底地形的强烈非线性相互作用以及内波破碎等因素有关.Extensive researches about internal waves are mostly from vertical profile observations; however, there are rare in-situ observation data to study horizontal characteristics of internal waves. Compared with the traditional physical oceanographic methods, reflection seismology has several advantages, such as high lateral resolution and the ability of imaging a large ocean profile in short time. Therefore, it is a promising observation technique for internal wave studies, which may make up the defects of traditional observation methods. Results from the reprocessing of a long multi-channel seismic profile in the northeastern margin of the South China Sea reveal clearly coherent undulating reflectors associated with internal waves in the water column. Horizontal wave number spectra of undulating reflectors are calculated and compared with the Garrett-Munk tow spectrum of oceanic internal wave displacements （GM76 spectrum）. The results show that internal wave horizontal wave-number spectra are generally consistent with the theoretical GM76 spectrum. However, there are differences in amplitudes and slopes in the low and high wave-number regions between the calculated and theoretical spectra, which are considered to be associated with strong interaction between the internal tides and the complex seafloor topography, and internal wave breaking, etc.

关 键 词：地震海洋学 海洋内波 内波谱 GM76模型 

分 类 号：P738[天文地球—海洋地质]