Venus wind and temperature structure - The Venera 8 data

Our analysis of the Venera 8 measurements yields equatorial morning terminator horizontal and vertical winds that are similar in a number of respects to the winds we obtained from our analysis of the Venera 7 measurements. The lower boundary of the horizontal retrograde '4-day' wind is defined by a 50-60% decrease in wind speed in the vicinity of 44 km, and there exists a retrograde wind 'plateau' of 15- to 40-m/s winds extending from 40 km down to the vicinity of 18 km, where the winds decrease rapidly to the order of 0.1 m/s near the surface. Updrafts of 2-5 m/s exist in the vicinity of 20-30 km and are apparently associated with a slightly superadiabatic lapse rate.