Combined optical and microwave remote sensing measurements of the stratosphere from a balloon platform: improving our understanding of ozone photochemistry

Combined infrared and microwave remote sensing measurements of the stratosphere are combined to test several aspects of a constrained photochemical model. The authors find that a model with conventional chemistry only is unable to reproduce the observed abundance of ClO and HOCl relative to HCl, while results from a model which includes 10% production of HCl from the reaction of OH and ClO are in good agreement with the observations. The modified model predicts that the rates of production and loss of ozone are in balance at altitudes where the photochemical lifetimes are short compared to the characteristic transport time (30-40 km), in agreement with the rates calculated directly from the authors´ measurements of HO₂, OH, NO₂ , O₃, and ClO. The modified model also shows that for the balloon flight analyzed halogen-catalyzed ozone loss plays a lesser role than previously believed