Thermal balance of Venus

The Pioneer Venus mission measured several parameters of the atmosphere of Venus which pertain to its temperature structure and thermal balance. Among them are the temperature profile, the composition of the atmosphere, the solar fluxes throughout the atmosphere, and the thermal fluxes throughout the atmosphere. The atmosphere is shown to be essentially adiabatic below about 35 or 40 km, but from there up to the bottom of the lower cloud (at approximately 47 km altitude) there is a subadiabatic region.