Superrotation on Venus: Driven By Waves Generated By Dissipation of the Transterminator Flow

Abstract

Context: The superrotation phenomenon in the atmosphere on Venus has been known since the late 60's. But until now no mechanism proposed has satisfactorily explained this phenomenon. Objective: The aim of this research is to propose a mechanism, until now never considered, which could drive the atmosphere of Venus in its superrotation. This mechanism involves the transfer of the transterminator ionospheric flow momentum to the lower atmosphere via pressure waves generated in the cryosphere of Venus. The mechanism proposed presents a source of energy sufficiently strong to allow the transfer of energy despite dissipation. Method: The energy flow which transports the transterminator flow and the energy lost by the viscosity in the superrotating atmosphere were calculated. Both results were compared to establish if there is sufficient energy in the transterminator flow to drive the superrotation. Finally, the amplitude that the waves should have to be able to obtain the momentum necessary to induce superrotation was calculated. Also an experimental model was made presenting some similarities with the process described. Results: The calculated power for the transterminator flow is 8.48x10e10 W. The calculated viscous dissipation of the superrotating flow is 1.4x10e9 W. Therefore, there is sufficient energy in the transterminator flow to maintain superrotation. The amplitude of the waves generated in the cryosphere, necessary to deposit the power dissipated by the viscous forces, is 10e-4 m for waves of 1 Hz and 10e-8 m for waves of 10e4 Hz. These amplitudes imply that at the altitude of the clouds on the night side there must be a constant sound of 83 dB. If the superrotation of Venus were to stop, with the continuous injection of 1.4x10e9 W, the actual superrotation would appear again in 1.4x10e6 years.