Analysis on diurnal global geomagnetic variability under quiet-time conditions

TL;DR

This study develops a PCA-based methodology using wavelet transforms to reconstruct and analyze the global diurnal geomagnetic variations during quiet days, providing a new approach for baseline determination.

Contribution

It introduces a novel PCA and wavelet correlation method to reconstruct global geomagnetic diurnal variations from multiple stations during quiet periods.

Findings

Successfully reconstructed the global diurnal variation baseline.

Demonstrated the effectiveness of wavelet-based PCA in geomagnetic analysis.

Encourages application of this approach to other geomagnetic studies.

Abstract

This paper describes a methodology (or treatment) to establish a representative signal of the global magnetic diurnal variation based on a spatial distribution in both longitude and latitude of a set of magnetic stations as well as their magnetic behavior on a time basis. For that, we apply the Principal Component Analysis (PCA) technique implemented using gapped wavelet transform and wavelet correlation. The continuous gapped wavelet and the wavelet correlation techniques were used to describe the features of the magnetic variations at Vassouras (Brazil) and other 12 magnetic stations spread around the terrestrial globe. The aim of this paper is to reconstruct the original geomagnetic data series of the H-component taking into account only the diurnal variations with periods of 24 hours on geomagnetically quiet days. With the developed work, we advance a proposal to reconstruct the baseline for the quiet day variations (Sq) from the PCA using the correlation wavelet method to determine the global variation of PCA first mode. The results showed that this goal was reached and encourage other uses of this approach to different kinds of analysis.