Satellite‐Borne Observations of Ozone Impact by the November 2001 Solar Proton Event

Abstract

A Solar Proton Event (SPE) occurs when, following a solar flare and coronal mass ejection, large quantities of protons are emitted toward the Earth and then subsequently accelerated to high energies (10-300 MeV). In near-Earth space, the protons are guided by the Earth's magnetic field to the polar regions. Their typical energies allow them to enter >60° geomagnetic latitudes (Verronen et al., 2007). Depending on their energies, they penetrate the upper and middle atmosphere and cause a direct significant impact at altitudes above 30 km (Jia et al., 2020). There, they cause ionization and dissociation in the middle atmosphere which leads to O 3 depletion (Sinnhuber et al., 2012).Since 1969, the SPE impact on middle atmospheric odd oxygen, O x (O 3 + O) has been studied (Weeks et al., 1972), and is overall a well-known phenomena (Funke et al., 2011;Jackman et al., 2001;Seppälä et al., 2004). In general, SPE causes increased production of odd hydrogen, HO x (H + OH + HO 2 ), and odd nitrogen, NO x (N + NO + NO 2 ), which then depletes O x through catalytic reactions. The increased HO x production happens through ion chemistry with molecular oxygen and water clusters reactions (