Extreme Value Analysis of Solar Flare Events

Abstract

Space weather events such as solar flares can be harmful for life and infrastructure on Earth or in near-Earth orbit. In this paper we employ extreme value theory to model extreme solar flare events; extreme value theory offers the appropriate tools for the study and estimation of probabilities for extrapolation to ranges outside of those that have already been observed. In this work the data points used are inherently independent and realistic confidence intervals are offered with respect to the estimates of future solar flare events. The data used in this study are peak X-ray fluxes provided by National Oceanic and Atmospheric Administration that form a series of distinct flare events. The expected return levels for Carrington- or Halloween storm-like events were calculated with the outcome that the existing data predict similar events happening in 110 and 38 years, respectively, which are consistent with the results and inferences provided by Elvidge and Angling (2018, https://doi.org/10.1002/2017SW001727). We also make a preliminary analysis of the implications of solar seasonality and found its effect on extreme flare events to be statistically insignificant.