KINETIC AND SPECTROSCOPIC REQUIREMENTS FOR THE MEASUREMENT OF MESOSPHERIC OZONE AT 9.6 MU-M UNDER NON-LTE CONDITIONS

Radiative emission from transitions involving the vibration-rotation b ands of ozone in the 9.6 mu m spectral region is readily detected by l imb-scanning instruments on orbiting satellites and such measurements are used to infer the ozone profile in the middle atmosphere. In the t errestrial mesosphere and lower thermosphere these transitions are pre dicted to depart from local thermodynamic equilibrium (LTE). The occur rence of non-LTE complicates the interpretation of emission measuremen ts in terms of the ozone abundance as the vibrational temperatures mus t be known a priori or calculated directly as part of the retrieval pr ocess. This in turn requires accurate knowledge of various kinetic and spectroscopic parameters used in a statistical equilibrium model to c alculate the vibrational temperatures. Through detailed simulations of the forward and inverse retrieval problem we find that in order to ac hieve retrieved ozone concentrations accurate to 15% the collisional q uenching rates must be known to better than 25% accuracy and that the distribution of energy within ozone upon recombination of O and O-2 mu st be significantly improved. Collisional quenching rates are currentl y uncertain by more than a factor of 2.