利用地震海洋学方法研究南海东北部东沙海域内孤立波的结构特征  

Nonlinear internal solitary waves in the northeast South China Sea near Dongsha Atoll using seismic oceanography

作　　者：拜阳[1] 宋海斌[1] 关永贤[2] 杨胜雄[2] 刘伯然[3,4] 陈江欣[3,4] 耿明会 

机构地区：[1]海洋地质国家重点实验室,同济大学海洋与地球科学学院,上海200092 [2]国土资源部海底矿产资源重点实验室,广州海洋地质调查局,广州510760 [3]中国科学院油气资源研究重点实验室,中国科学院地质与地球物理研究所,北京100029 [4]中国科学院大学,北京100049

出　　处：《科学通报》2015年第10期944-951,共8页Chinese Science Bulletin

基　　金：国家自然科学基金(91128205;41076024);国家重点基础研究发展计划(2011CB403503)资助

摘　　要：主要利用地震海洋学方法研究了南海东北部东沙海域内孤立波的结构特征,内孤立波的类型是第一模态下沉型,最大振幅有85.5 m.内孤立波自最大振幅所处深度向下,其振幅大体呈线性减小趋势,振幅随深度的减小率为0.2左右.海底对内孤立波的波形会产生一些影响,一方面海底可能会“切割”内孤立波底部,使之出现间断,另一方面海底的“摩擦”会导致近海底的内孤立波处会发育有较多次一级尺度的波动.横向上看,由地震剖面所得到的内孤立波视宽度,需经过一定的校正才能获得真实宽度,本文所研究的两个内孤立波视宽度分别是4.52和3.36 km,校正后的宽度为0.5～3 km.另外内孤立波处存在的垂向噪音反映出内孤立波具有很强的垂向剪切力.内孤立波水平波数谱与GM模型谱的对比研究表明,其能量在低波数段比GM谱大两个数量级左右.We studied nonlinear internal solitary waves in the northeast South China Sea near Dongsha Atoll, mainly using seismic oceanography The type of internal solitary wave examined was the first mode depression wave, with maximum amplitude 85.5 m. From the depth of this amplitude and below, the amplitude of solitary waves generally decreased linearly, and the rate of decrease with depth was about 0.2. The seafloor can influence the waveforms of these waves. Specifically, the seafloor can “cut” the bottom of solitary waves, making them discontinuous, and the seafloor “friction” can induce many short waves near it. The apparent width of solitary waves directly from seismic sections should be corrected to obtain true width. Apparent widths of two solitary waves studied were 4.52 and 3.36 km; these were about 0.5-3 km after correction. There was vertical noise at solitary wave locations, reflecting strong vertical shear forces there. The contrast between horizontal wavenumber spectra of the solitary waves and GM （Garrett Munk） model spectra indicate that their wave energy was about two orders of magnitude larger than the GM spectra at low wave numbers.

关 键 词：内孤立波 孤立子 地震海洋学 南海 东沙 

分 类 号：P731.24[天文地球—海洋科学]