PROPAGATION AND TRAPPING OF GLOBAL OSCILLATIONS IN THE JOVIAN TROPOSPHERE AND STRATOSPHERE

The propagation of acoustic waves in the Jovian troposphere is revisited, in order to estimate their thermal signature. A new expression for the cutoff frequency of global oscillation pressure oscillations is proposed, related to the analysis of the propagation in its natural system of variables. Distinction is clearly made between Jovian global modes trapped in the planetary interior and sound waves propagating in the stratosphere. The cutoff frequency of Jovian modes is about 3 mHz. When energy equipartition between the pressure waves is assumed, it is found that the oscillation velocity of the waves in the troposphere increases linearily with the frequency, and with a very limited dependence in function of the detection levels. The strong dependence of the thermal signature as a function of the oscillation velocity is calculated for the different frequencies at various depths. Same calculations are also conducted for the pressure perturbation associated to the wave. Finally, the factor of quality depending on the efficiency of the trapping is estimated.