A Lapse Rate is standard for planetary and moon atmospheres in the solar system. See Alan Siddons via NASA planetary fact sheets, and Common 0.1 bar Tropopause in Thick Atmospheres Set by Pressure-Dependent Infrared Transparency, 2013, by Tyler D Robinson and David C. Catling, DOI: 10.1038/ngeo2020
Temperature–pressure profiles for worlds in the Solar System with thick atmospheres [refs: 1, 2, 3, 4, 28]. Temperature minima commonly occur around 0.1 bar. Venus has a very weak 0.1 bar tropopause in the global mean (see text). More information regarding data sources is given in the Supplementary Information (to above paper).