Hitting a Moving Target: Modeling Non-Stationary Relationships in Geomagnetism

• Activity Number: 11 - Statistical Inference for Solar and Geophysical Data
• Type: Invited
• Date/Time: Monday, August 3, 2020 : 10:00 AM to 11:50 AM
• Sponsor: Section on Physical and Engineering Sciences
• Author(s): David Riegert* and David J Thomson and Glen Takahara
• Companies: Queen's University and Queen's University and Queen's University
• Keywords: nonstationary; time series; signal processing; spectrum; magnetotellurics; transfer function

Abstract

This talk focuses on modelling the relationship between Earth's magnetic field as a predictor and induced currents in the ground as a response; a field of study known as magnetotellurics. Current modelling approaches assume a stationary relationship, however energy transfer between frequencies, indicating non-stationarity in the process, has been investigated in the univariate setting using seismic, ocean pressure (Chave et al., 2019), and geomagnetic measurements (Chave et al., 2018; Riegert & Thomson, 2018). Non-stationarity in a time-series process provides strong evidence for a non-stationary relationship between that series and any other. Current models are discussed and an extension is introduced which aims to account for violations in the assumption of stationarity.