Effects of ENSO on Southern Hemisphere Jet Structures
Column ozone anomalies correlate highly with barotropic temperature anomalies in the UTLS, and may be linked to distinctive patterns of Antarctic surface temperature and wind anomalies for El Nino versus La Nina. During the SH winter to spring transition a westward shift in convection during La Nina of 30-50° corresponds to a 30-50° westward shift of planetary wave patterns from the tropics to Antarctica and of the zonal asymmetry in column ozone. In SH winter and spring during La Nina, a region of significant poleward planetary wave activity flux in the UTLS occurs near (amplified) Indonesian convection, while during El Nino the poleward flux is weaker and more diffuse across the Pacific. A primary result is that La Nina favors a barotropic low pressure anomaly over the Ross Sea, a colder East Antarctica, and a more displaced but stronger polar vortex. The influence of ENSO on the structure of the subtropical jet, subpolar jet, and its vertical coherence with the polar night jet is highlighted.