Evaluation of ACE-FTS and OSIRIS satellite retrievals of ozone and nitric acid in the upper troposphere: Application to ozone production efficiency

We evaluate climatologies of upper tropospheric ozone and nitric acid retrieved from the ACE-FTS and OSIRIS satellite instruments. Both satellite retrievals reproduce broad ozone features in the upper troposphere such larger concentrations in the tropical Atlantic versus the tropical Pacific. These comparisons indicate biases in annual, tropical mean ozone concentrations from both ACE-FTS (13-21 %) and OSIRIS (5-6%) relative to aircraft (MOZAIC) and ozonesonde observations. Less definitive evidence suggests that nitric acid from ACE-FTS has a positive median bias of less than 15%. We demonstrate that an upper limit on the ozone production efficiency in the upper troposphere can be determined using satellite measurements of O 3 and HNO3, and apply our approach to ACE-FTS. The resulting value of 170+/-30 mol/mol is in broad agreement with model simulations. This analysis indicates a new capability of satellite observations to provide insight into ozone production in the tropical troposphere.