Northern Hemisphere Stratospheric Ozone and the Polar Vortex: SPEs and SSWs

Ozonesonde data from four sites in the northern hemisphere are analyzed in relation to 191 solar proton events (SPEs) and 37 sudden stratospheric warmings (SSWs) from 1989 to 2016. Once the data are seasonally corrected, we demonstrate that ozone depletion ( 10-35 km altitude) commences rapidly following the SPEs during winter/early-spring when the polar vortex (PV) generally occurs. We show that such depletions occur only in winter/early spring above sites where the northern hemisphere polar vortex (PV) can be present. A rapid reduction in stratospheric ozone is observed with the maximum decrease occurring 10-20 days after SPEs. Ozone levels remain depleted in excess of 30 days. In contrast, we observe a rapid increase in temperature and ozone following SSWs. The association of the winter-time PV in our results suggests that the rapid transport of long-lived NOx species plays a role in causing indirect ozone destruction following SPEs. When the PV is disrupted during SSWs there is a rapid increase in stratospheric ozone. No change in ozone is observed above sites completely outside the PV for SPEs or SSWs. No change in ozone is observed in relation to random epochs at any site at any time of year. Analysis of ozonesonde data is presented along with supporting ozone observations from AURA/MLS, mesospheric winds measurements from a meteor radar, and ground-based total column measurements of ozone and NO2 from a radiometer present at one of the ozonesonde launch sites.