Atmosphere of Venus in north polar area based on radio transmission data from Venera-15 and Venera-16 spacecraft

The history of Soviet and American radio transmission studies of the Venusian atmosphere is briefly outlined. Results are presented from studies of the atmosphere in the North polar area, analyzing changes in the status of the atmosphere at 40 to 90 altitude, 81 to 89 deg latitude, 81 to 95 deg solar zenith angles, from 14 to 31 October 1983. Nine regions in the Northern Hemisphere of the planet are covered.