We thank Huw Davies for invaluable advice, Jeffrey Annis for his help with a pilot study to this project, Daniela Domeisen for proofreading, George Kiladis and an anonymous reviewer for their valuable feedback and suggestions, and Meteo Swiss for granting access to the ERA-Interim data set. The satellite images were downloaded from the National Climatic Data Center. Publication costs have been covered by the German Research Foundation (DFG) as part of the research unit PANDOWAE (FOR 896).
Bordoni, S., , and T. Schneider, 2010: Regime transitions of steady and time-dependent Hadley circulations: Comparisons of axisymmetric and eddy-permitting simulations. J. Atmos. Sci., 67, 1643–1654.
Dee, D. P., and Coauthors, 2011: The ERA-Interim reanalysis: Configuration and performance of the data assimilation system. Quart. J. Roy. Meteor. Soc., 137, 553–597, doi:10.1002/qj.828.
Dritschel, D. G., , and M. E. McIntyre, 2008: Multiple jets as PV staircases: The Philips effect and the resilience of eddy-transport barriers. J. Atmos. Sci., 65, 855–874.
Feldstein, S. B., , and U. Dayan, 2008: Circumglobal teleconnections and wave packets associated with Israeli winter precipitation. Quart. J. Roy. Meteor. Soc., 134, 455–467.
Funatsu, B. M., , and D. W. Waugh, 2008: Connections between potential vorticity intrusions and convection in the eastern tropical Pacific. J. Atmos. Sci., 65, 987–1002.
Gill, A. E., 1982: Atmosphere–Ocean Dynamics. Academic Press, 645 pp.
Held, I. M., , and A. Y. Hou, 1980: Nonlinear axially symmetric circulations in a nearly inviscid atmosphere. J. Atmos. Sci., 37, 515–533.
Held, I. M., , and P. Phillips, 1990: A barotropic model of the interaction between the Hadley cell and a Rossby wave. J. Atmos. Sci., 47, 856–869.
Hoskins, B. J., , and D. J. Karoly, 1981: The steady linear response of a spherical atmosphere to thermal and orographic forcing. J. Atmos. Sci., 38, 1179–1196.
Isotta, F., , O. Martius, , M. Sprenger, , and C. Schwierz, 2008: Long-term trends of synoptic-scale breaking Rossby waves in the Northern Hemisphere between 1958 and 2001. Int. J. Climatol., 28, 1551–1562, doi:10.1002/joc.1647.
Kiladis, G. N., 1998: Observations of Rossby waves linked to convection over the eastern tropical Pacific. J. Atmos. Sci., 55, 321–339.
Kiladis, G. N., , and K. M. Weickmann, 1992: Extratropical forcing of tropical Pacific convection during northern winter. Mon. Wea. Rev., 120, 1924–1938.
Knippertz, P., 2005: Tropical–extratropical interactions associated with an Atlantic tropical plume and subtropical jet streak. Mon. Wea. Rev., 133, 2759–2776.
Koch, P., , H. Wernli, , and H. C. Davies, 2006: An event-based jet-stream climatology and typology. Int. J. Climatol., 26, 283–301.
Lee, S., , and H.-K. Kim, 2003: The dynamical relationship between subtropical and eddy-driven jets. J. Atmos. Sci., 60, 1490–1503.
Martius, O., , C. Schwierz, , and H. C. Davies, 2007: Breaking waves at the tropopause in the wintertime Northern Hemisphere: Climatological analyses of the orientation and the theoretical LC1/2 classification. J. Atmos. Sci., 64, 2576–2592.
Martius, O., , C. Schwierz, , and H. C. Davies, 2008: Far-upstream precursors of heavy precipitation events on the Alpine south-side. Quart. J. Roy. Meteor. Soc., 134, 417–428.
Ploeger, F., and Coauthors, 2011: Insight from ozone and water vapour on transport in the tropical tropopause layer (TTL). Atmos. Chem. Phys., 11, 407–419.
Reiter, E. R., , and L. F. Whitney, 1969: Interaction between subtropical and polar-front jet stream. Mon. Wea. Rev., 97, 432–438.
Rossa, A. M., , H. Wernli, , and H. C. Davies, 2000: Growth and decay of an extratropical cyclone’s PV-tower. Meteor. Atmos. Phys., 73, 139–156.
Seidel, D. J., , Q. Fu, , W. J. Randel, , and T. J. Reichler, 2008: Widening of the tropical belt in a changing climate. Nat. Geosci., 1, 21–24.
Shuckburgh, E., , F. Ovidio, , and B. Legras, 2009: Local mixing events in the upper troposphere and lower stratosphere. Part II: Seasonal and interannual variability. J. Atmos. Sci., 66, 3695–3706.
Sprenger, M., , M. Croci-Maspoli, , and H. Wernli, 2003: Tropopause folds and cross-tropopause exchange: A global investigation based upon ECMWF analyses for the time period March 2000 to February 2001. J. Geophys. Res., 108, 8518, doi:10.1029/2002JD002587.
Vallis, G. K., 2006: Atmospheric and Oceanic Fluid Dynamics. Cambridge University Press, 745 pp.
Wernli, H., , and H. C. Davies, 1997: A Lagrangian-based analysis of extratropical cyclones. 1. The method and some applications. Quart. J. Roy. Meteor. Soc., 123, 467–489.
The following groups were chosen: PV > 4 PVU, 3 < PV < 4 PVU, 2 < PV < 3 PVU, 1 < PV < 2 PVU, and PV < 1 PVU. The choice of PV categories is to a certain degree arbitrary.