HR: 0800h
AN: A31A-0010    [Abstracts]
TI: An Idealized General Circulation Model for the Study of Stratospheric-Tropospheric Coupling
AU: * Gerber, E P
EM: epg2108@columbia.edu
AF: Columbia Univeristy, Dept. Applied Physics and Applied Mathematics, New York, NY 10027, United States
AU: Polvani, L M
EM: lmp@columbia.edu
AF: Columbia Univeristy, Dept. Applied Physics and Applied Mathematics, New York, NY 10027, United States
AU: Waugh, D W
EM: waugh@jhu.edu
AF: Johns Hopkins University, Dept. of Earth and Planetary Sciences, Baltimore, MD 21218, United States
AB: An idealized General Circulation Model of the atmosphere is developed to investigate the dynamical coupling between the stratosphere and troposphere. The model is similar to that of Polvani and Kushner (2002, GRL), but with the addition of topographically induced stationary planetary waves, which prove to be essential for coupling between the spheres on intraseasonal timescales. The frequency of sudden warming events and the timescale at which events descend through the stratosphere -- and sometimes into the troposphere -- is explored. We find that the mean structure and variability of the polar vortex is very sensitive to the amplitude of the topography, and Northern Hemisphere-like variability, with the correct frequency of warming events, occurs only for a relatively narrow range of topographic heights. The addition of a seasonal cycle also allows for the analysis of final warming events. The timing of the final warming is of particular interest, as it has been difficult to capture in more sophisticated models.
DE: 1626 Global climate models (3337, 4928)
DE: 3305 Climate change and variability (1616, 1635, 3309, 4215, 4513)
DE: 3319 General circulation (1223)
DE: 3334 Middle atmosphere dynamics (0341, 0342)
DE: 3362 Stratosphere/troposphere interactions
SC: Atmospheric Sciences [A]
MN: 2007 Fall Meeting