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Dong L. Wu and Stephen D. Eckermann

1. Introduction Gravity waves (GWs) play a key role in the global meteorology, climate, chemistry, and microphysics of the stratosphere and mesosphere ( Fritts and Alexander 2003 ). Because finite computational resources force global climate–chemistry and weather prediction models to run at spatial resolutions that do not adequately resolve GW dynamics, these important GW-induced effects must be parameterized (e.g., McLandress 1998 ; Kim et al. 2003 ). Arguably the greatest weakness in

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Kaoru Sato and Motoyoshi Yoshiki

downward control principle proposed by Haynes et al. (1991) , the gravity wave force drives a global-scale meridional circulation from the summer to winter poles around the mesopause and maintains the latitudinal gradient of temperature, which is the reverse of what would be expected from the latitudinal distribution of solar radiation. It is also thought that gravity waves may have similar effects on the meridional circulation in the stratosphere (i.e., the Brewer–Dobson circulation), although

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Yonghui Lin and Fuqing Zhang

Wave Regional or Global Tracer (GROGRAT) model developed in Marks and Eckermann (1995) and Eckermann and Marks (1997) is used in this study to track the propagation and amplitude evolution of gravity waves. GROGRAT computes gravity wave group trajectories through gridded numerical representations of the background atmosphere, using a fully nonhydrostatic dispersion relation containing both rotation and density stratification, accounting for refraction due to three-dimensional spatial gradients

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David A. Schecter

proportional to Fr 4 Ω in the regime where Fr ≪ 1. This result was later generalized by Plougonven and Zeitlin (2002) to “pancake” vortices in a continuously stratified fluid. It stands to reason that an atmospheric vortex at small Froude number would hardly feel the effects of radiation. Nevertheless, mesoscale cyclones such as hurricanes and rotational thunderstorms ( Fig. 1 ) can penetrate the “superspin” parameter regime, where both the Rossby and Froude numbers exceed unity. Recent numerical studies

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Shuguang Wang, Fuqing Zhang, and Chris Snyder

1984 ; Marks and Eckermann 1995 ). Lin and Zhang (2008) studied the wave characteristics along rays of gravity waves in the baroclinic jet front systems simulated in Zhang (2004) . Here, we will use the Gravity-Wave Regional or Global Ray Tracer (GROGRAT; Marks and Eckermann 1995 ; Eckermann and Marks 1997 ), a numerical ray tracing model, to examine the effect of the strong flow deformation on the propagation properties of jet exit region gravity waves. Specifically, we seek to understand

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