A Numerical Study of the Atmospheric Circulation on Venus

Abstract

The atmospheric circulation on Venus was studied by means of numerical integrations of the governing equations. In the main part of the calculations, stationary solar heating was assumed and the atmospheric circulation was calculated using spherical polar coordinates. A horizontal wind was found directed from the subsolar to the antisolar points in the upper part of the atmosphere where the radiative differential heating dominates, but oppositely directed in the lower part of the atmosphere. Analysis of the atmospheric energy balance has shown that the upward motion near the subsolar point cools the atmosphere where the atmosphere is heated by insulation and that the downward motion near the antisolar point warms the atmosphere where infrared cooling prevails. The planetary radiation budget and the energy balance due to atmospheric circulation were in good agreement. In additional calculations, we investigated the effect of moving solar heating due to planetary differential rotation relative to the sun. The calculated wind field was remarkable by its fast response with little time lag to moving solar heating. Based on this result, together with the calculations with fixed solar heating, we infer that the general circulation of the Venusian atmosphere is probably a bipolar circulation with respect to the subsolar and antisolar points moving along the solar equator at a speed of ?3 m sec?1.