[Previous] | [Session 10] | [Next]
M. E. Koukouli, P. G. J. Irwin, F. W. Taylor (Atmospheric, Oceanic and Planetary Physics, Oxford University)
We have used Pioneer Venus Orbiter Infrared Radiometer observations of thermal emission from Venus' middle atmosphere between 10S and 90N to determine temperature, cloud optical depth and water vapour mixing ratio profiles as a function of altitude. The spectral regions observed include the 45 micron rotational water band and the strong 15 micron carbon dioxide band. New radiative transfer and retrieval models have been developed based on correlated-k tables calculated with new line data. Preliminary results from the new retrievals are presented and discussed in the context of the remarkably high abundance of water vapour in the early afternoon, almost a hundred times the planet-wide average, in a localised region above the cloud-tops at equatorial latitudes reported in previous studies. The sulphuric acid cloud opacity and scattering properties have been recalculated from new refractive index data using Mie theory. It is found that the inclusion of scattering does not lead to significantly different radiances than those calculated from more simple thermal emission models.
The author(s) of this abstract have provided an email address for comments about the abstract: mek@atm.ox.ac.uk