Footprint of Multi-Equilibrium States in a Venusian Atmospheric General Circulation Model

Abstract

We investigated the possibility of multiple equilibrium states in the atmospheric general circulation of Venus using Venus-like AGCM. We ran the model from two initial conditions. For a zero zonal wind initial condition, super-rotation is not reproduced and slow rotation appears. In a case with large zonal wind, increasing linearly with height initial condition, quasi-steady super-rotation with about 90 ms^-1 zonal wind is reproduced. However, this state suddenly collapsed and settled to slow rotation, which suggests the existence of a footprint of the equilibrium state with super-rotation in addition to the slow-rotation state in the solution space, along with the possibility of multiple equilibrium states. Results show that the wave with wavenumber one controls this collapse of super-rotation.