Exceptional middle latitude electron precipitation detected by balloon observations: implications for atmospheric composition

Abstract

Abstract. Energetic particle precipitation leads to ionization in the Earth's atmosphere, initiating the formation of active chemical species which destroy ozone and have the potential to impact atmospheric composition and dynamics down to the troposphere. We report on one exceptionally strong high-energy electron precipitation event detected by balloon measurements in middle latitudes on 14 December 2009 with ionization rates locally comparable to strong solar proton events. This electron precipitation was likely caused by wave-particle interactions in the slot region between the inner and outer radiation belts, connected with still not well understood natural phenomena in the magnetosphere. Satellite observations of odd nitrogen and nitric acid are consistent with wide-spread electron precipitation into magnetic midlatitudes. Simulations with a 3D chemistry-climate model indicate almost complete destruction of ozone in the upper mesosphere over the region where high-energy electron precipitation occurred. Such an extraordinary type of energetic particle precipitation can have major implications for the atmosphere, and their frequency and strength should be carefully studied.

Diagnostic study of geomagnetic storm-induced ionospheric changes over very low-frequency signal propagation paths in the mid-latitude D region

“…The outer radiation belt can relax to its more quiescent state on timescales ranging from minutes (Turner et al, 2013) to many days (Baker, 2019) following a significant geomagnetic storm. It should be noted, in conclusion, that although the evidence provided herein shows a clear association of magnetic storms with enhanced levels of electron precipitation, it is likely that even during geomagnetically quiet intervals electron precipitation persists but apparently at a greatly reduced rate (Mironova et al, 2021).…”