Model of daytime emissions of electronically-vibrationally excited products of O₃ and O₂ photolysis: application to ozone retrieval

The traditional kinetics of electronically excited products of O₃ andO₂ photolysis is supplemented with the processes of the energy transferbetween electronically-vibrationally excited levels O₂(a¹&Delta;_g, v) and O₂(b¹&Sigma;⁺_g, v), excited atomicoxygen O(¹D), and the O₂ molecules in the ground electronic stateO₂(X³&Sigma;_g^&minus;, v). In contrast to the previous modelsof kinetics of O₂(a¹&Delta;_g) and O₂ (b¹&Sigma;⁺_g), our model takes into consideration the following basicfacts: first, photolysis of O₃ and O₂ and the processes of energyexchange between the metastable products of photolysis involve generation ofoxygen molecules on highly excited vibrational levels in all consideredelectronic states &ndash; b¹&Sigma;⁺_g, a¹&Delta;_g and X³&Sigma;_g^&minus;; second, the absorption of solar radiationnot only leads to populating the electronic states on vibrational levelswith vibrational quantum number v equal to 0 &ndash; O₂b¹&Sigma;⁺_g, v=0 (at 762 nm) and O₂a¹&Delta;_g, v=0 (at 1.27 &micro;m), but also leads to populating the excitedelectronic&ndash;vibrational states O₂b¹&Sigma;⁺_g, v=1 and O₂b¹&Sigma;⁺_g, v=2 (at 689 nm and 629 nm). Theproposed model allows one to calculate not only the vertical profiles of theO₂a¹&Delta;_g, v=0 and O₂b¹&Sigma;<sup+</sup>_g, v=0 concentrations, but also the profiles of [O₂(a¹&Delta;_g, v&le;5)], \[O₂ b¹&Sigma;⁺_g , v=1, 2\] and O₂X³&Sigma;_g^&minus;, v=1&ndash;35. In the altitude range 60&ndash;125 km, consideration of theelectronic-vibrational kinetics significantly changes the calculatedconcentrations of the metastable oxygen molecules and reduces the discrepancybetween the altitude profiles of ozone concentrations retrieved from the 762-nm and 1.27-&micro;m emissions measuredsimultaneously.