The application of Spectral-Direction method in marine electromagnetic data processing
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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.
Abstract: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.
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图 2
合成数据PSD分析结果，信号主频为0.3 Hz
Figure 2.
PSD analysis of the synthetic data and the main frequency of the signal is 0.3 Hz
图 3
合成数据极化分析结果，信号极化方向为120°
Figure 3.
Polarization analysis of the synthetic data and the polarization direction of the signal is 120°
图 4
合成信号模拟参数(a)与时频方向谱分析结果(b)
Figure 4.
The modeling parameters (a) and SD analysis (b) of the synthetic data
图 5
发射源移动方向和采集站实测方位示意图
Figure 5.
Schematic of transmitter′s navigation and OBEM′s orientation
图 6
南海实测海底电场分量Ex(a)和Ey(b)频谱图
Figure 6.
Spectrogram of the electric field components Ex (a) and Ey (b) measured at South China Sea
图 7
近场源处电场水平分量Ex和Ey的时间序列(a)及其极化分析结果(b)
Figure 7.
Time-series of the electric field components Ex and Ey close to the transmitter source (a) and the polarization analysis results (b)
图 8
实测海洋CSEM信号时频方向谱
Figure 8.
Spectral-Direction analysis of the measured marine CSEM data
图 10
南黄海某电磁采集站实测水平磁场分量Hx(a)和Hy(b)的时频谱
Figure 10.
Spectrogram of the horizontal magnetic components Hx (a) and Hy (b), measured at the Southern Yellow Sea
图 11
南黄海某电磁采集站实测磁场时频方向谱
Figure 11.
The Spectral-Direction analysis of the marine magnetic field, measured at the Southern Yellow Sea
名称 周期 频率(Hz) 恢复力 表面张力波 < 0.1 s >10 表面张力 超重力波 0.1~1 s 1~10 表面张力和重力 重力波
(涌浪等)1~30 s 0.03~1 重力 次重力波 30 s~5 min 0.003~0.03 重力和科里奥利力 长周期波 5 min~12 h 0.00003~0.003 重力和科里奥利力 潮波(潮汐) 12~24 h 0.00001~0.00003 重力和科里奥利力 
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表 2
时频方向谱估计海水运动方向统计表
Table 2.
Statistics of ocean motion direction by SD method
阶段 频带 0.05~0.3 Hz 0.3~10 Hz 平均值 平潮期
(23:00—01:00)106.5°~146.4° - 125.2° 涨潮期
(01:00—05:00)- 89.5°~132.8° 115.9° 平潮期(05:00—07:00) 54.8°~109.2° - 74.5° 退潮期
(07:00—11:00)- 94.9°~127.1° 108.6° 平潮期
(11:00—13:00)26.2°~92.1° - 51.4° 退潮期
(13:00—17:00)- 131.3°~123.6° 112.9° 平潮期
(17:00—19:00)59.5°~118.2° - 81.4° 退潮期
(19:00—23:00)- 104.5°~131.6° 112.1°
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Beal H T, Weaver J T. 1970. Calculations of magnetic variations induced by internal ocean waves. Journal of Geophysical Research, 75(33):6846-6852. doi: 10.1029/JC075i033p06846
Behrens J P. 2005. The detection of electrical anisotropy in 35 Ma Pacific lithosphere:Results from a marine controlled-source electromagnetic survey and implications for hydration of the upper mantle[Ph. D. thesis]. San Diego:University of California.
Bhatt K M, Hördt A, Hanstein T. 2009. Analysis of seafloor marine EM data with respect to motion-induced noise.//23rd Kolloquium Electromagnetische Tiefenforschung (EMTF). Brandenburg, Germany
Bhatt K M. 2011. Motion induced noise in marine electromagnetic data[Ph. D. thesis]. Braunschweig, Lower Saxony, Germany:Technical University.
Chave A D, Filloux J H. 1984. Electromagnetic induction fields in the deep ocean off California:oceanic and ionospheric sources. Geophysical Journal International, 77(1):143-171. doi: 10.1111/j.1365-246X.1984.tb01929.x
Chave A D, Luther D S. 1990. Low-frequency, motionally induced electromagnetic fields in the ocean:1. Theory. Journal of Geophysical Research, 95(C5):7185-7200. doi: 10.1029/JC095iC05p07185
Constable S. 2006. Marine electromagnetic methods-A new tool for offshore exploration. The Leading Edge, 25(4):438-444. doi: 10.1190/1.2193225
Constable S. 2010. Ten years of marine CSEM for hydrocarbon exploration. Geophysics, 75(5):75A67-75A81. http://d.old.wanfangdata.com.cn/NSTLQK/10.1190-1.3483451/
Constable S. 2013. Review paper:Instrumentation for marine magnetotelluric and controlled source electromagnetic sounding. Geophysical Prospecting, 61(S1):505-532. http://cn.bing.com/academic/profile?id=ad0d7a8609f86e7b2d919dde2e8ed1c1&encoded=0&v=paper_preview&mkt=zh-cn
Cox C. 1980. Electromagnetic induction in the oceans and inferences on the constitution of the earth. Geophysical Surveys, 4(1-2):137-156. doi: 10.1007/BF01452963
Crews A, Futterman J. 1962. Geomagnetic micropulsations due to the motion of ocean waves. Journal of Geophysical Research, 67(1):299-306. doi: 10.1029/JZ067i001p00299
Faraday M. 1832. VI. The Bakerian lecture.-Experimental researches in electricity.-Second series. Philosophical Transactions of the Royal Society of London, (122):163-194. doi: 10.1098/rstl.1832.0007
Fraser D C. 1966. The magnetic fields of ocean waves. Geophysical Journal International, 11(5):507-517. doi: 10.1111/j.1365-246X.1966.tb03162.x
Key K, Lockwood A. 2010. Determining the orientation of marine CSEM receivers using orthogonal Procrustes rotation analysis. Geophysics, 75(3):F67-F70. doi: 10.1190/1.3454771
Larsen J C. 1973. An introduction to electromagnetic induction in the ocean. Physics of the Earth and Planetary Interiors, 7(3):389-398. doi: 10.1016/0031-9201(73)90063-0
Li Y G, Duan S M. 2014. Data preprocessing of marine controlled-source electromagnetic data. Periodical of Ocean University of China (in Chinese), 44(10):106-112.
Lin Z H, Li Y G. 2019. Calculations of magnetic variations induced by ocean waves. Periodical of Ocean University of China (in Chinese), 49(2):74-78. http://d.old.wanfangdata.com.cn/Periodical/qdhydxxb201902010
Liu Y H, Yin C C, Weng A H, et al. 2012. Attitude effect for marine CSEM system. Chinese J. Geophys. (in Chinese), 55(8):2757-2768, doi:10.6038/j.issn.0001-5733.2012.08.027.
Longuet-Higgins M S, Stern M E, Stommel H. 1954. The electrical field induced by ocean currents and waves, with applications to the method of towed electrodes.//Physical Oceanography and Meteorology, Vol.13. Cambridge and Woods Hole: Massachusetts Institute of Technology and Woods Hole Oceanographic Institution.
Luo M, Pei J X, Xu Z H. 2017. Effects of uncertainties in the orientation and position of both the transmitter and receivers on marine CSEM responses in layered vertical anisotropic medium. Chinese J. Geophys. (in Chinese), 60(12):4901-4915, doi:10.6038/cjg20171229.
Myer D, Constable S, Key K, et al. 2012. Marine CSEM of the Scarborough gas field, Part 1:Experimental design and data uncertainty. Geophysics, 77(4):E281-E299. doi: 10.1190/geo2011-0380.1
Podney W. 1975. Electromagnetic fields generated by ocean waves. Journal of Geophysical Research, 80(21):2977-2990. doi: 10.1029/JC080i021p02977
Reddy M P M. 2001. Descriptive Physical Oceanography. Netherlands:A. A. Balkema.
Sanford T B. 1971. Motionally induced electric and magnetic fields in the sea. Journal of Geophysical Research, 76(15):3476-3492. doi: 10.1029/JC076i015p03476
Shimizu H, Utada H. 2015. Motional magnetotellurics by long oceanic waves. Geophysical Journal International, 201(1):390-405. doi: 10.1093/gji/ggv030
Shin K, Hammond J K. 2008. Fundamentals of Signal Processing for Sound and Vibration Engineers. Singapore:John Wiley & Sons, Ltd.
Sugioka H, Hamano Y. 2016. Practical performance evaluation of the Wave Glider in geophysical observations.//EGU General Assembly Conference. EGU.
Toh H, Satake K, Hamano Y, et al. 2011. Tsunami signals from the 2006 and 2007 Kuril earthquakes detected at a seafloor geomagnetic observatory. Journal of Geophysical Research, 116(B2):B02104, doi:10.1029/2010JB007873.
Tyler R H, Mysak L A. 1995. Motionally-induced electromagnetic fields generated by idealized ocean currents. Geophysical & Astrophysical Fluid Dynamics, 80(3-4):167-204. http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=10.1080/03091929508228954
Weaver J T. 1971. The general theory of electromagnetic induction in a conducting half-space. Geophysical Journal of the Royal Astronomical Society, 22(1):83-100. doi: 10.1111/j.1365-246X.1971.tb03584.x
Welch P D. 1967. The use of fast Fourier transform for the estimation of power spectra:A method based on time averaging over short, modified periodograms. IEEE Transactions on Audio and Electroacoustics, 15(2):70-73. doi: 10.1109/TAU.1967.1161901
Xu Z H, Liu Y, Li Y G. 2016. Effects of uncertainties in the position and orientation of both the transmitter and receivers on marine controlled-source electromagnetic data. Journal of Ocean University of China, 15(1):83-92. doi: 10.1007/s11802-016-2675-8
Xu Z H, Li Y G, Luo M. 2018. Seabed survey and property analysis of ship's shaft-rate electromagnetic signal. Journal of Harbin Engineering University (in Chinese), 39(4):652-657. http://d.old.wanfangdata.com.cn/Periodical/hebgcdxxb201804007
Yaakobi O, Zilman G, Miloh T. 2011. Detection of the electromagneticfield induced by the wake of a ship moving in a moderate sea state of finite depth. Journal of Engineering Mathematics, 70(1-3):17-27. doi: 10.1007/s10665-010-9410-z
Young F B, Gerrard H, Jevons W. 1920. XIII. On electrical disturbances due to tides and waves. The London, Edinburgh, and Dublin Philosophical Magazine and Journal of Science, 40(235):149-159. http://d.old.wanfangdata.com.cn/NSTLQK/NSTL_QKJJ0232029961/
李予国, 段双敏. 2014.海洋可控源电磁数据预处理方法研究.中国海洋大学学报(自然科学版), 44(10):106-112. http://d.old.wanfangdata.com.cn/Periodical/qdhydxxb201410015
林智恒, 李予国. 2019.海水运动感应磁场的数值计算方法.中国海洋大学学报(自然科学版), 49(2):74-78. http://d.old.wanfangdata.com.cn/Periodical/qdhydxxb201902010
刘云鹤, 殷长春, 翁爱华等. 2012.海洋可控源电磁法发射源姿态影响研究.地球物理学报, 55(8):2757-2768, doi:10.6038/j.issn.0001-5733.2012.08.027. http://www.geophy.cn//CN/abstract/abstract8845.shtml
罗鸣, 裴建新, 徐震寰. 2017.层状垂直各向异性介质海洋CSEM发射源及接收站姿态和位置对电磁响应影响研究.地球物理学报, 60(12):4901-4915, doi:10.6038/cjg20171229. http://www.geophy.cn//CN/abstract/abstract14224.shtml
徐震寰, 李予国, 罗鸣. 2018.船舶轴频电磁场信号的海底测量及其特性分析.哈尔滨工程大学学报, 39(4):652-657. http://d.old.wanfangdata.com.cn/Periodical/hebgcdxxb201804007
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