We thank the Natural Sciences and Engineering Research Council of Canada and the Canadian Foundation for Climate and Atmospheric Sciences for support. Much of this work was completed at the Aspen Center for Physics 2005 Workshop on Novel Approaches to Climate. We also thank Maarten Ambaum (for correcting a mistake in the analysis related to Fig. 5), Edwin Gerber (for the idea of the using the Δps index), as well as Adam Monahan, John Fyfe, and the manuscript’s reviewers for helpful comments.
Ambaum, M. H. P., , B. J. Hoskins, , and D. B. Stephenson, 2001: Arctic Oscillation or North Atlantic Oscillation? J. Climate, 14 , 3495–3507.
Baldwin, M., , and T. J. Dunkerton, 1999: Propagation of the Arctic Oscillation from the stratosphere to the troposphere. J. Geophys. Res., 104 , 30937–30946.
Cash, B. A., , P. J. Kushner, , and G. K. Vallis, 2002: The structure and composition of the annular modes in an aquaplanet general circulation model. J. Atmos. Sci., 59 , 3399–3414.
Cash, B. A., , P. J. Kushner, , and G. K. Vallis, 2005: Zonal asymmetries, teleconnections, and annular patterns in a GCM. J. Atmos. Sci., 62 , 207–219.
Cash, B. A., , P. J. Kushner, , and G. K. Vallis, 2007: Comment on “On the presence of annular variability in an aquaplanet model” by Masahiro Watanabe. Geophys. Res. Lett., 34 .L03707, doi:10.1029/2006GL027274.
Gerber, E. P., 2006: A dynamical and statistical understanding of the North Atlantic Oscillation and annular modes. Ph.D. thesis, Princeton University, 242 pp.
Gerber, E. P., , and G. Vallis, 2005: A stochastic model for the spatial structure of annular patterns of variability and the North Atlantic Oscillation. J. Climate, 18 , 2102–2118.
Hoskins, B. J., , I. N. James, , and G. H. White, 1983: The shape, propagation, and mean-flow interaction of large-scale weather systems. J. Atmos. Sci., 40 , 1595–1612.
Rashid, H., , and I. Simmonds, 2004: Eddy–zonal flow interactions associated with the Southern Hemisphere annular mode: Results from NCEP–DOE reanalysis and a quasi-linear model. J. Atmos. Sci., 61 , 873–888.
Robinson, W. A., 2004: Comments on “The structure and composition of the annular modes in an aquaplanet general circulation model.”. J. Atmos. Sci., 61 , 949–953.
Simmons, A. J., , and B. J. Hoskins, 1976: Baroclinic instability on the sphere: Normal modes of the primitive and quasi-geostrophic equations. J. Atmos. Sci., 33 , 1454–1477.
Tanaka, H. L., , and H. Tokinaga, 2002: Baroclinic instability in high latitudes induced by a polar vortex: A connection to the Arctic Oscillation. J. Atmos. Sci., 59 , 69–82.
Thompson, D. W. J., , and J. M. Wallace, 1998: The Arctic Oscillation signature in the wintertime geopotential height and temperature fields. Geophys. Res. Lett., 25 , 1297–1300.
Thompson, D. W. J., , and J. M. Wallace, 2000: Annular modes in the extratropical circulation. Part I: Month-to-month variability. J. Climate, 13 , 1000–1016.
Vallis, G. K., , E. P. Gerber, , P. J. Kushner, , and B. A. Cash, 2004: A mechanism and simple dynamical model of the North Atlantic Oscillation and annular modes. J. Atmos. Sci., 61 , 264–280.
Wallace, J. M., 2000: North Atlantic Oscillation/Northern Hemisphere annular mode: One phenomenon, two paradigms. Quart. J. Roy. Meteor. Soc., 126 , 791–805.
Watanabe, M., 2005: On the presence of annular variability in an aquaplanet model. Geophys. Res. Lett., 32 .L05701, doi:10.1029/2004GL021869.