An aerosol transport model based on a two-moment microphysical parameterization in the Venus middle atmosphere: Model description and preliminary experiments

On Venus, the upper haze layer (70-90 km) is observed above the cloud layer (48-70 km). An aerosol transport model using a two-moment microphysical parameterization for the cloud and upper haze is developed and is applied to a wide height range of 24-94 km. The latitudinal dependence of the SO₂ oxidation mainly leads to the equator-pole contrast of the aerosol mass loading, and the meridional circulation weakens the equator-pole contrast of the mass loading through the poleward mass transport. The equator-pole contrast of the aerosol number concentration is enhanced by the meridional circulation in the middle atmosphere. The haze transport due to the meridional circulation should be considered as an important process in the formation of the equator-pole contrast of the Venus cloud structure.