Relativistic Electron Microburst Events: Modeling the Atmospheric Impact

Abstract

Relativistic electron microbursts are short-duration, high-energy precipitation events that are an important loss mechanism for radiation belt particles. Previous work to estimate their atmospheric impacts found no significant changes in atmospheric chemistry. Recent research on microbursts revealed that both the fluxes and frequency of microbursts are much higher than previously thought. We test the seasonal range of atmospheric impacts using this latest microburst information as input forcing to the Sodankylä Ion and Neutral Chemistry model. A modeled 6 h microburst storm increased mesospheric HOx by 15–25%/800–1,200% (summer/winter) and NOx by 1,500–2,250%/80–120%. Together, these drive 7–12%/12–20% upper mesospheric ozone losses, with a further 10–12% longer-term middle mesospheric loss during winter. Our results suggest that existing electron precipitation proxies, which do not yet take relativistic microburst energies into account, are likely missing a significant source of precipitation that contributes to atmospheric ozone balance.