Abstract

Energetic electron precipitation (EEP) forms ozone-depleting nitrogen and hydrogen oxides in the high-latitude middle and upper atmosphere, leading to ozone destruction and temperature enhancement that can strengthen the winter polar vortex. This EEP effect on polar vortex depends on quasi-biennial oscillation and sudden stratospheric warmings, which earlier studies relate to planetary waves. We study here the possible modulation of the EEP effect by planetary waves. We perform a principal component analysis of the vertical component of Eliassen-Palm flux (EP flux) to examine the latitudinal pattern of planetary waves. We use a multilinear regression analysis to estimate the responses of zonal wind and EP flux divergence to EEP in the northern winter stratosphere by keeping the two leading principal components of vertical EP flux as controlling factors. We find that the EEP strengthens the polar vortex most systematically when planetary wave propagation is enhanced at mid-latitudes but reduced at polar latitudes.