A normalmode approach to Jovian atmospheric dynamics.
Abstract
The authors propose a nonlinear, quasigeostrophic, baroclinic model of Jovian atmospheric dynamics, in which vertical variations of velocity are represented by a truncated sum over a complete set of orthogonal functions obtained by a separation of variables of the linearized quasigeostrophic potential vorticity equation. A set of equations for the time variation of the mode amplitudes in the nonlinear case is then derived. The authors show that for a planet with a neutrally stable, fluid interior instead of a solid lower boundary, the barotropic mode represents motions in the interior, and is not affected by the baroclinic modes. One consequence of this is that a normalmode model with one baroclinic mode is dynamically equivalent to a one layer model with solid lower topography. The authors also show that for motions in Jupiter's cloudy lower troposphere, the stratosphere behaves nearly as a rigid lid, so that the normalmode model is applicable to Jupiter. The authors test the accuracy of the normalmode model for Jupiter using two simple problems: forced, vertically propagating Rossby waves, using two and three baroclinic modes, and baroclinic instability, using two baroclinic modes. The authors find that the normalmode model provides qualitatively correct results, even with only a very limited number of vertical degrees of freedom.
 Publication:

Journal of Atmospheric Sciences
 Pub Date:
 August 1989
 DOI:
 10.1175/15200469(1989)046<2448:ANMATJ>2.0.CO;2
 Bibcode:
 1989JAtS...46.2448A
 Keywords:

 Atmospheric Models;
 Jupiter Atmosphere;
 Planetary Meteorology;
 Baroclinic Waves;
 Orthogonal Functions;
 Rossby Regimes;
 Stratosphere;
 Troposphere;
 Vorticity Equations;
 Lunar and Planetary Exploration;
 Jupiter Atmosphere: Dynamics