Forecasting solar flare activity using an inferred solar stress index

• Activity Number: 24
• Type: Topic Contributed
• Date/Time: Sunday, August 3, 2014 : 2:00 PM to 3:50 PM
• Sponsor: Section on Physical and Engineering Sciences
• Author(s): Aaron Springford*+ and David J. Thomson and David Riegert
• Companies: Queen's University and Queen's University and
• Keywords: multitaper ; spectrum estimation ; dynamic model ; forecasting ; solar

Abstract

Solar activity can have appreciable damaging effects on Earth-based power transmission systems. Solar storms in particular cause large variations in Earth's magnetic field, inducing current in transmission lines and causing damage to sensitive power transformers and other equipment. Power companies are interested in predicting when such storms will occur in order to mitigate damages, but current forecast horizons are only on the order of days. We present a forecasting approach based on the hypothesis that subsurface stresses initiate solar flare events, which can result in coronal mass ejections and solar storms at Earth. Our approach uses multitaper spectral estimates of solar gravity modes to forecast a cumulative solar stress index using a very simple state-space model. In retrospective analysis, this stress index was found to be correlated with variance in log X-ray data measured near Earth by GOES spacecraft. Using this index, we generated a six month qualitative forecast of the likelihood of large flare events beginning November 1, 2013. We discuss the performance of our forecast and its utility for management of power transmission systems over an extended time horizon.