Propagation of planetary-scale zonal mean wind anomalies and polar oscillations

Global atmospheric variables can be physically decomposed into four components: (1) the zonal time averaged climate symmetric component, (2) the time averaged climate asymmetric, (3) the zonal-mean transient symmetric anomaly, and (4) the transient asymmetric anomaly. This study analyzes the relationships between the intra-seasonal and inter-annual variability of planetary scale decomposed zonal and meridional winds in the tropopause, and oscillations such as those from the El Ni o-Southern Oscillation (ENSO), the Arctic Oscillation (AO) and the Antarctic Oscillation (AAO). The tropical inter-annual zonal mean wind anomalies in the tropopause are linked with the ENSO cycle and can propagate into the subtropics, mid-latitudes, and polar front regions via abnormal meridional vertical cells. Similarly, tropical intra-seasonal (40–60-d) zonal wind anomalies can reach the subtropics and mid-latitudes. The polar intra-seasonal zonal wind anomalies in the tropopause can propagate toward high-latitude areas. Thus, the AO and the AAO are the result of the interaction and propagation of these planetary scale zonal wind anomalies.