浅水区海洋可控源电磁场传播规律研究  

The propagation characteristics of marine controlled-source electromagnetic fields in shallow waters

作　　者：李超帆 李刚[1] LI ChaoFan;LI Gang(Department of Marine Sciences,Zhejiang University,Zhoushan Zhejiang 316021,China)

机构地区：[1]浙江大学海洋科学系,浙江舟山316021

出　　处：《地球物理学报》2025年第4期1567-1578,共12页Chinese Journal of Geophysics

基　　金：国家自然科学基金项目(42076060)资助。

摘　　要：浅水区海洋可控源电磁场的传播较为复杂.本文基于可控源电磁理论和渐进空间域空气波表达式,利用矢量相减的方法分离电场并进一步开展可控源电场传播规律的探索研究.数值实验表明,可控源电场在传播过程中会发生全反射、半波损失及多路径传播下波场干扰抵消现象,在浅水区尤其需要考虑界面多重反射的影响.此外,根据波场传播规律分析结果,进行海底电性结构探测时,需压制在海水及空气-海水界面传播为主的空气波这类强干扰波的影响.进行水下目标体定位时,由于目标体多出现在于海水中,因此近场情况下需压制海底界面导波,远场情况下需要尽可能地利用能量较强的空气波和界面多次反射信号.Assessing the propagation of the marine controlled-source electromagnetic(EM)fields in shallow waters presents a formidable challenge.This paper addresses this complexity by applying marine controlledsource EM theory and asymptotic expression for the airwave.Our methodology utilizes a vector subtraction technique to separate the electric field,allowing for a thorough investigation of marine electric field propagation.The numerical tests in this study reveal salient phenomena including total reflection,half-wave loss,and interference cancellation as the electric field propagates through a wave field with multiple paths.In shallow waters,the interface multiple reflection should not be overlooked.To better understand the subseafloor conductivity structures in marine controlled-source EM surveys,effective airwave suppression strategies are required,particularly those that travel through seawater and the sea-air interface.Moreover,for successful underwater target detection,careful consideration must be implemented to suppress guided waves along the seafloor interface,particularly in near-source field data.In contrast,for field data collected distant from the source,the airwaves,and multiple reflections become strong signals,providing helpful insights for underwater target detection.

关 键 词：浅水区 海洋可控源电磁场 波场分离 

分 类 号：P738[天文地球—海洋地质] P631[天文地球—海洋科学]