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| | Abstract | | Empirical mode decomposition (EMD) is a technique, which is a part of Hilbert-Huang transform (HHT), to transform original time-series data to narrow-band time-series data called intrinsic mode function (IMF). In order to examine characteristics of MT time-series data, EMD was applied to artificial and observed MT data. As the result of numerical analysis using simulation data, time-series data can be transformed to correct sine waves. In case of time-series data with rectangular noise, it was found that low-frequency IMF was strongly affected by rectangular noise. As the result of EMD using MT data which was observed in Ito Campus of Kyushu University, ten IMFs were detected in electric field and nine IMFs were detected in magnetic field. This result means that there are at least nine spectrum in this MT data. |
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