时频方向谱分析在海洋电磁数据处理中的应用  

The application of Spectral-Direction method in marine electromagnetic data processing

作　　者：徐震寰 李予国[1,2] XU ZhenHuan;LI YuGuo(Key Lab of Submarine Geosciences and Prospecting Techniques,Ministry of Education,College of Marine Geosciences,Ocean University of China,Qingdao 266100,China;Evaluation and Detection Technology Laboratory of Marine Mineral Resources,Qingdao National Laboratory for Marine Science and Technology,Qingdao 266100,China)

机构地区：[1]海底科学与探测技术教育部重点实验室,中国海洋大学海洋地球科学学院,青岛266100 [2]青岛海洋科学与技术国家实验室海洋矿产资源评价与探测技术功能实验室,青岛266100

出　　处：《地球物理学报》2019年第12期4874-4885,共12页Chinese Journal of Geophysics

基　　金：国家自然科学基金重点项目（41130420）;中国海洋大学海底科学与探测技术教育部重点实验室开放课题基金（SGPT-2019OF-09）联合资助

摘　　要：海底采集到的电磁数据按照其主要包含的信息及研究目的大致可分为海洋可控源电磁场(CSEM)信号、天然场源大地电磁场(MT)信号、海洋环境电磁场信号以及其他随机干扰信号.常常通过计算功率谱密度、时频分析和极化分析的方法研究海洋电磁场特征.本文介绍一种新方法——时频方向谱分析法及其在实测海洋电磁数据处理中的应用,该方法能够在一定的时间-频率尺度上有效分辨场源信号的运动方向.对于海洋CSEM数据,利用该方法可以估算发射源的运动方向,进而在发射源或采集站方位信息缺失情况下,实现海洋CSEM数据的旋转电性轴处理.对于海洋电磁数据,利用该方法可以详细分析海水运动感应电磁场的信号特征.The electromagnetic data collected on the seabed can be roughly divided into the marine controlled-source electromagnetic field(CSEM)signal,the natural source magnetotelluric(MT)signal,the marine environment electromagnetic signal and random noises.The characteristics of marine electromagnetic fields were often studied by using power spectral density,time-frequency analysis and polarization analysis.In this paper,we introduce a new method namely the Spectral-Direction analysis method and present its application on marine electromagnetic survey data processing.This method can effectively resolve the direction of the field source on a certain time-frequency scale.For marine CSEM data,this method can be used to estimate the moving direction of the towed-transmitter,and then the rotational electric axis of the marine CSEM data can be processed in the absence of the azimuth information of the transmitter(or receiver).For marine electromagnetic data,this method can be used to analyze the signal characteristics of the motion induced electromagnetic field of seawater.

关 键 词：时频方向谱分析 海洋电磁数据处理 海洋环境电磁场 海洋可控源电磁法 

分 类 号：P631[天文地球—地质矿产勘探]