An Ensemble Approach to Extreme Space Weather Event Probability -- A First Look

Abstract:

An extreme space weather event has the potential to disrupt or damage infrastructure systems and technologies that many societies rely on for economic and social wellbeing. Space weather events occur regularly, but extreme events occur less frequently with only several historical examples over the last 160 years. During the past decade, published works have (1) forensically examined the physical characteristics of the extreme historical events; and (2) discussed the probability or return rate of select extreme geomagnetic disturbances, including the 1859 Carrington event.

Here we present an analysis of several of these studies. We created a unified statistical framework to visualize previous analyses, and developed a model from an ensemble using statistical methods. We look at geomagnetic disturbance probability across multiple return periods. We discuss what the most likely 100-year extreme event (a parameter of interest to policy makers and planners) and the return period for other extreme historical events. We discuss the current state of these analyses, their utility to policy makers and planners, the current limitations (in data and understanding) when compared to other hazards, and the gaps that need to be filled to enhance space weather risk assessments.