TY  - STD
AU  - Larnier, H.
PY  - 2016//
TI  - Using magnetic observatories as reference stations in magnetotelluric data processing of geomagnetic pulsations
N2  - IAGA Workshop on on Geomagnetic Observatory Instruments, Data acquisition and Processing, Dourbes, Belgium, September 2016Magnetotellurics (MT) is a passive geophysical exploration technique which uses time series of natural magnetic and electric fields measured at the ground surface. It is based on the induction of electric currents in the ground by large scale geomagnetic waves. A wide collection of waves is used in MT, from lightning strikes emitted waves to magnetic pulsations induced by the interaction of the sun and the magnetosphere. In this work, we have developed a methodology based on the continuous wavelet transform to process MT data in the period range [1-500] seconds based on the time-frequency characteristics of geomagnetic pulsations. In this period range, geomagnetic pulsations are the preponderant signals. To properly detect geomagnetic pulsations in MT time series, we are generating Fourier surrogates of quiet magnetic time series. Then, by comparison between the distribution of wavelets coefficients of these surrogates and the original signal, we are recovering significant wavelet coefficients associated to geomagnetic pulsations. The magnetic observatories are of primary importance in this framework as their data are used as large-scale reference station for the occurrence of geomagnetic events. We are showing several datasets and their consecutive analysis with regards to improvement brought by magnetic observatories data onto the characterization of MT transfer functions.
N1  - exported from refbase (http://publi.ipev.fr/polar_references/show.php?record=6394), last updated on Mon, 01 Jul 2024 21:22:43 +0200
ID  - Larnier2016
ER  -