Superrotation Induced by Critical-Level Absorption of Gravity Waves on Venus: An Assessment

Abstract

Critical-level absorption of a continuous spectrum of vertically propagating gravity waves is proposed as the mechanism for supporting the superrotation in the deep Venus atmosphere (below the cloud deck). It is shown that the observed westerly zonal wind effectively separates regions where waves of opposite phase speeds are absorbed, leading to westerly mean-flow acceleration below the clouds and easterly above. Using the diagnostic results of Hou and Goody, we obtain a quantitative assessment of the required wave spectrum and fluxes of energy and momentum, and show that they are compatible with observational constraints.