Seawater motion-induced electromagnetic noise reduction in marine magnetotelluric data using current meters
Abstract Seawater motion-induced electromagnetic (EM) noise along the seafloor has a large impact on marine magnetotelluric (MT) data quality. Although the mechanical stability of ocean bottom electromagnetic receivers (OBEMs) has improved due to buoyancy optimization, completely eliminating EM nois...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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SpringerOpen
2020-01-01
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| Series: | Earth, Planets and Space |
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| Online Access: | https://doi.org/10.1186/s40623-019-1129-0 |
| _version_ | 1818959292712091648 |
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| author | Kai Chen Qingxian Zhao Ming Deng Xianhu Luo Jianen Jing |
| author_facet | Kai Chen Qingxian Zhao Ming Deng Xianhu Luo Jianen Jing |
| author_sort | Kai Chen |
| collection | DOAJ |
| description | Abstract Seawater motion-induced electromagnetic (EM) noise along the seafloor has a large impact on marine magnetotelluric (MT) data quality. Although the mechanical stability of ocean bottom electromagnetic receivers (OBEMs) has improved due to buoyancy optimization, completely eliminating EM noise generated by seafloor currents as a result of instrument rocking or induction from the Earth’s magnetic field is still not possible. The velocity of the current represents the quantification of seafloor conditions. To mitigate this problem, we installed a current meter on an OBEM to measure the synchronous current velocity along with the OBEM data logger. For the marine EM surveys, we conducted two surveys composed of 42 marine EM data acquisition sites in the South China Sea. We observed a strong correlation between induced EM noise and current velocity when the speed was greater than 2 cm/s. Furthermore, we developed an adaptive correlation noise-canceling filter to reduce the induced EM noise, using the current meter data as a reference signal. The filter refined the coefficients using a least-mean-squares algorithm. We were able to reduce the induced EM noise by pre-filtering the raw time series data with an adaptive correlation noise-canceling filter and using current meter data from nearby sites. Since seafloor currents are clearly an issue that limits MT data quality, special efforts are necessary to reduce seawater motion-induced EM noise in marine MT surveys. |
| first_indexed | 2024-12-20T11:39:20Z |
| format | Article |
| id | doaj.art-803fe5b93db94a41b4075c3dd34f3def |
| institution | Directory Open Access Journal |
| issn | 1880-5981 |
| language | English |
| last_indexed | 2024-12-20T11:39:20Z |
| publishDate | 2020-01-01 |
| publisher | SpringerOpen |
| record_format | Article |
| series | Earth, Planets and Space |
| spelling | doaj.art-803fe5b93db94a41b4075c3dd34f3def2022-12-21T19:42:00ZengSpringerOpenEarth, Planets and Space1880-59812020-01-0172111110.1186/s40623-019-1129-0Seawater motion-induced electromagnetic noise reduction in marine magnetotelluric data using current metersKai Chen0Qingxian Zhao1Ming Deng2Xianhu Luo3Jianen Jing4School of Geophysics and Information Technology, China University of GeosciencesInstitute of Marine Geological Exploration Method and Technology, Guangzhou Marine Geology SurveySchool of Geophysics and Information Technology, China University of GeosciencesInstitute of Marine Geological Exploration Method and Technology, Guangzhou Marine Geology SurveySchool of Geophysics and Information Technology, China University of GeosciencesAbstract Seawater motion-induced electromagnetic (EM) noise along the seafloor has a large impact on marine magnetotelluric (MT) data quality. Although the mechanical stability of ocean bottom electromagnetic receivers (OBEMs) has improved due to buoyancy optimization, completely eliminating EM noise generated by seafloor currents as a result of instrument rocking or induction from the Earth’s magnetic field is still not possible. The velocity of the current represents the quantification of seafloor conditions. To mitigate this problem, we installed a current meter on an OBEM to measure the synchronous current velocity along with the OBEM data logger. For the marine EM surveys, we conducted two surveys composed of 42 marine EM data acquisition sites in the South China Sea. We observed a strong correlation between induced EM noise and current velocity when the speed was greater than 2 cm/s. Furthermore, we developed an adaptive correlation noise-canceling filter to reduce the induced EM noise, using the current meter data as a reference signal. The filter refined the coefficients using a least-mean-squares algorithm. We were able to reduce the induced EM noise by pre-filtering the raw time series data with an adaptive correlation noise-canceling filter and using current meter data from nearby sites. Since seafloor currents are clearly an issue that limits MT data quality, special efforts are necessary to reduce seawater motion-induced EM noise in marine MT surveys.https://doi.org/10.1186/s40623-019-1129-0Marine magnetotelluricAdaptive correlation noise-canceling filterSeawater motion-induced electromagnetic noiseCurrent meter |
| spellingShingle | Kai Chen Qingxian Zhao Ming Deng Xianhu Luo Jianen Jing Seawater motion-induced electromagnetic noise reduction in marine magnetotelluric data using current meters Earth, Planets and Space Marine magnetotelluric Adaptive correlation noise-canceling filter Seawater motion-induced electromagnetic noise Current meter |
| title | Seawater motion-induced electromagnetic noise reduction in marine magnetotelluric data using current meters |
| title_full | Seawater motion-induced electromagnetic noise reduction in marine magnetotelluric data using current meters |
| title_fullStr | Seawater motion-induced electromagnetic noise reduction in marine magnetotelluric data using current meters |
| title_full_unstemmed | Seawater motion-induced electromagnetic noise reduction in marine magnetotelluric data using current meters |
| title_short | Seawater motion-induced electromagnetic noise reduction in marine magnetotelluric data using current meters |
| title_sort | seawater motion induced electromagnetic noise reduction in marine magnetotelluric data using current meters |
| topic | Marine magnetotelluric Adaptive correlation noise-canceling filter Seawater motion-induced electromagnetic noise Current meter |
| url | https://doi.org/10.1186/s40623-019-1129-0 |
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