A visualization of the global dynamic tropopause

A 20-yr loop of the global tropopause, defined in terms of potential vortic ity (PV); is constructed using the NCEP-NCAR reanalysis dataset. This metho d of visualizing observed upper-tropospheric dynamics is useful for studyin g a wide range of phenomena. Examples are given of the structure of jet str eams and planetary-scale tropopause folds, the propagation of a high-amplit ude Rossby wave packet partway around a hemisphere, several subtropical wav e breaking events, the similarities between exceptional cases of rapid cycl ogenesis, favorable regions for cross-equatorial propagation of Rossby wave s, the annual cycle of the tropical tropopause, the structure of the Tibeta n anticyclone and equatorial easterly jet associated with the Asian monsoon , the meridional structure of the upper branch of the Hadley cell, the inte raction of a hurricane and midlatitude trough to form the "Perfect Storm," and the upper-tropospheric PV changes associated with El Nino and La Nina. Plumes of anticyclonic potential vorticity are frequently seen to be pulled from the subtropical reservoir and roll up into large anticyclones. These previously undescribed plumes may be particularly relevant to jet streak dy namics and stratosphere-troposphere exchange.