TY - JOUR
T1 - Influence of geomagnetic storms on the quality of magnetotelluric impedance
AU - Chen, Hao
AU - Mizunaga, Hideki
AU - Tanaka, Toshiaki
N1 - Funding Information:
This work was supported by JST SPRING, Grant Number JPMJSP2136. We thank all SAMTEX and USArray team members for providing the time-series data used in this study. We thank INTERMAGNET (International Real-time Magnetic Observatory Network) for providing the magnetic time-series data observed at the KAK station. We thank the WDC for Geomagnetism, Kyoto, for providing the Dst index data to analyze the geomagnetic storm. Finally, we express special thanks to Maik Neukirch, Benjamin Murphy and Peng Han for their constructive comments to improve the manuscript. We also thank Ute Weckmann, Louise Alexander, Takeshi Sagiya and several anonymous reviewers who reviewed the manuscript and gave us constructive comments to improve the manuscript.
Publisher Copyright:
© 2022, The Author(s).
PY - 2022/12
Y1 - 2022/12
N2 - Magnetotelluric (MT) field data contain natural electromagnetic signals and artificial noise sources (instrumental, anthropogenic, etc.). Not all available time-series data contain usable information on the electrical conductivity distribution at depth with a low signal-to-noise ratio. If variations in the natural electromagnetic signal increase dramatically in a geomagnetic storm, the signal-to-noise ratio increases. A more reliable impedance may be obtained using storm data in a noisy environment. The field datasets observed at mid-latitudes were used to investigate the effect of geomagnetic storms on MT impedance quality. We combined the coherence between the electric and magnetic fields and the result of the MT sounding curve to evaluate the MT impedance quality across all periods and combined the phase difference among the electric and magnetic fields, the polarization direction, and the hat matrix to discuss the data quality for a specific period simultaneously. The case studies showed that the utilization of the data observed during the geomagnetic storm could overcome the local noise and bring a more reliable impedance. Graphical Abstract: [Figure not available: see fulltext.]
AB - Magnetotelluric (MT) field data contain natural electromagnetic signals and artificial noise sources (instrumental, anthropogenic, etc.). Not all available time-series data contain usable information on the electrical conductivity distribution at depth with a low signal-to-noise ratio. If variations in the natural electromagnetic signal increase dramatically in a geomagnetic storm, the signal-to-noise ratio increases. A more reliable impedance may be obtained using storm data in a noisy environment. The field datasets observed at mid-latitudes were used to investigate the effect of geomagnetic storms on MT impedance quality. We combined the coherence between the electric and magnetic fields and the result of the MT sounding curve to evaluate the MT impedance quality across all periods and combined the phase difference among the electric and magnetic fields, the polarization direction, and the hat matrix to discuss the data quality for a specific period simultaneously. The case studies showed that the utilization of the data observed during the geomagnetic storm could overcome the local noise and bring a more reliable impedance. Graphical Abstract: [Figure not available: see fulltext.]
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U2 - 10.1186/s40623-022-01659-6
DO - 10.1186/s40623-022-01659-6
M3 - Article
AN - SCOPUS:85134364286
SN - 1343-8832
VL - 74
JO - earth, planets and space
JF - earth, planets and space
IS - 1
M1 - 111
ER -