The proper characterization of ozone mid-ir radiances under non-LTE conditions is

very important for the retrieval of mesospheric constituents, such as ozone or carbon

monoxide. A recent study of Kaufmann et al. [2006] indicated very large Envisat-

MIPAS radiances at 4.8 um and suggested significant changes to standard non-LTE

models of ozone to fit the measurements. To verify and extend these results, we developed

a new ozone non-LTE model for the main vibrational-translational (VT) relaxation

channels of ozone based on the theory of Schwartz-Slawsky-Herzfeld. The VT

relaxation rates are compared with the standard approach using a Landau-Teller type

scaling law. In addition to VT relaxation, we also consider vibrational-vibrational energy

exchange with O2 for various transitions and demonstrate the importance of this

relaxation path for many vibrational levels. Finally, the non-LTE model parameters are

constrained by comparing simulated 5um radiances with observations of the MIPAS

instrument at stratospheric altitudes where the atmospheric state can be characterized

from MIPAS measurements not affected by non-LTE.