Zonally asymmetric ozone and its effect on the planetary waveguide

Using the NOGAPS-ALPHA high altitude general circulation model, we find that zonally asymmetric ozone (ZAO) produces a profound change in the Northern Hemisphere planetary waveguide. We have previously shown that ZAO alters the propagation and attenuation (damping) of vertically propagating planetary waves; together, changes in wave propagation and attenuation combine to alter the divergence of the Eliassen-Palm flux (EP-flux) and hence the zonal-mean circulation. We find that including ZAO produces a poleward shift in the lower stratospheric zero-wind line and an increase in the upper stratospheric index of refraction. In combination, the changes within the upper and lower stratosphere produce a change in the Northern Hemisphere planetary waveguide that increases the vertical propagation of planetary waves. The altered waveguide increases the EP-flux divergence within the upper stratosphere and thus produces a warmer and weaker stratospheric polar vortex. We discuss the ability of ZAO to alter the flux of planetary wave energy into the polar vortex in the context of the frequency of sudden stratospheric warmings and the driving of the Brewer-Dobson circulation.