[PPS06-09] Determination of the homopause altitude on Venus from SOIR/VEx observations
Keywords:Venus, Mesosphere, Homopause
The homopause is an altitude region separating the homosphere and the heterosphere. In the homosphere, eddy diffusion exceeds molecular diffusion, such that all the gases are all well mixed. Their vertical distribution all have the same scale height. In the heterosphere, the opposite occurs, and gases are not well mixed anymore. Consequently, each species follows its own scale height, function of the species’ molecular weight.
In this work, we present computations of the mean homopause altitude at the terminator based on the CO and CO2 simultaneously measured number density profiles, and the corresponding temperature profiles. We found out that it is located at a pressure level of 10-4 mbar (~120 km). The results are compared to a 1D vertical diffusion code, which accounts for eddy and molecular diffusions.
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