Overview of the NCAR-MOPITT reanalysis, investigation of chemical error correlations

Atmospheric Carbon Monoxide (CO) is an important trace gas in tropospheric chemistry through its impact on the oxidizing capacity, as a precursor of ozone, and as a good tracer of combustion from both anthropogenic sources and wildfires. More than 10 years of retrievals from the MOPITT (Measurement of Pollution in the Troposphere) instrument have been assimilated into the global Community Atmosphere Model with Chemistry (CAM-CHEM), the atmospheric component of the Community Earth System Model (CESM). First, an overview of the reanalysis results will be presented, with a focus on the evaluation of the ability of the system to capture the CO spatio-temporal variability, in particular for large events such as wildfire and pollution outflow as well as long-term trends. The DART/CAM-Chem system used for the reanalysis is based on an ensemble adjustment Kalman filter (EAKF) framework which facilitates statistical estimation of error correlations between chemical states (CO and related species). We will use the MOPITT-Reanalysis statistics to investigate the potential for analysis sensitivity studies for chemistry using ensemble techniques. The ozone-CO correlations will serve as a demonstration by comparing ozone-CO statistics to observations using in-situ aircraft measurements from NASA campaigns and the MOZAIC-IAGOS program.