CLOUD PATTERNS, WAVES AND CONVECTION IN VENUS ATMOSPHERE

The authors provide morphological and kinematic descriptions of the UV markings seen in the Mariner 10 imagery of Venus: the dark horizontal Y, bow-like waves, circumequatorial belts, subsolar disturbance, spiral streaks and bands, polar ring and polar region. The dark horizontal Y is interpreted as a westward-propagating planetary wave with zonal wavenumber 1 and period approximately 4. 2 days; it may be the superposition of a Rossby-Haurwitz wave dominant at mid-latitudes and a Kelvin wave dominant in equatorial regions. Bow-like waves may be true bow waves formed by the interaction of the rapid zonal flow with internal gravity waves of lower horizontal phase speeds generated by the subsolar disturbance. Circumequatorial belts are interpreted as internal gravity waves with horizontal wavelength approximately 500 km and zonal extent approximately 5000 km.