Study of the Ring Current Variability with the Use of Ground-Based Magnetometer Measurements and New Statistical Technique: Preliminary Results

The ground-based magnetometer measurement at low- and mid-latitudes has been one of the major tools for the study of the ring current variability. But the recorded data are always contaminated by the magnetic effects of other M-I current systems and they are multi-scaled, impulsive, and asynchronous with non-stationary frequency spectra. Therefore, they are not amenable to traditional time domain or spectral (Fourier) analysis. In this talk, we will present the preliminary results from a pilot study of the ring current variability, in which multiple components of magnetometer data from different latitudes and longitudes are coherently analyzed with a technique based on the wavelet analysis, a statistical tool that is especially suitable for analyzing the data that are impulsive and have time-dependent spectra. We will demonstrate that the technique is able to 1) screen out the magnetic effects from other M-I current systems; 2) distinguish the developments of the asymmetric ring current and the symmetric ring current during magnetic storm periods; 3) infer the variability of the ring currents from the “cleaned” magnetometer data in the wavelet domain. This statistical technique will have a broad range of space weather applications and will be very useful for the space science community.