南海海盆东北部内孤立波的地震海洋学研究  

Seismic oceanography study of internal solitary waves in the northeastern South China Sea Basin

作　　者：范文豪 宋海斌[1] 张锟 许鹤翰 龚屹 孙绍箐 FAN WenHao;SONG HaiBin;ZHANG Kun;HSU Hohan;GONG Yi;SUN ShaoQing(State Key laboratory of Marine Geology,School of Ocean and Earth Science,Tongji University,Shanghai 200092,China;Institute of Oceanography,Taiwan University,Taipei,China)

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]台湾大学海洋研究所,中国台北

出　　处：《地球物理学报》2020年第7期2644-2657,共14页Chinese Journal of Geophysics

基　　金：国家重点研发计划(2018YFC0310000);全球变化专项国际合作项目(GASI-GEOGE-05);国家自然科学基金(41976048,41576047)资助.

摘　　要：以往利用地震海洋学方法发现的内孤立波大多在东沙岛附近,本文在南海海盆东北部首次利用地震海洋学方法发现了海盆中的内孤立波.通过叠前偏移观察该内孤立波细结构的变化,发现内孤立波波形在采集时间段内整体较稳定,内孤立波浅层反射相对深层变化较大.通过改进前人的方法,利用共偏移距道集叠前偏移剖面计算内孤立波视相速度.该方法比直接使用共偏移距道集拟合的共中心点-炮点对曲线线性更好,其计算的内孤立波视相速度为0.82m·s^-1,内孤立波视传播方向为从NW向SE(172°N方向,0°指向北).In previous work,the internal solitary waves(ISWs)discovered by seismic oceanography are mostly near the Dongsha Island.This paper uses the method of seismic oceanography to find the ISWs in the basin for the first time in the northeastern South China Sea.The pre-stack migration is used to examine the changes of the ISWs structure.It is found that the ISWs waveforms are stable overall during the acquisition period.The shallow reflection of the ISWs has a relatively larger change than the deep.By improving the methods of the predecessors,the ISWs apparent phase velocity is calculated by pre-stack migration profile using the Common Offset Gather(COG).The fitting curve of CMP(Common Mid-Point)-shot point pairs using this method has a better linearity than that using Common Offset Gather directly.The apparent phase velocity of this ISWs using the improved method is 0.82 m·s^-1,and the apparent direction of the ISWs propagation is from NW to SE(172°N,0°pointing north).

关 键 词：地震海洋学 内孤立波 南海海盆 结构特征 传播特征 

分 类 号：P738[天文地球—海洋地质]