Using 3DVAR data assimilation system to improve ozone simulations in the Mexico City basin
1Molina Center for Energy and the Environment, La Jolla, CA, USA
2Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technolology, Cambridge, MA, USA
3Saint Louis University, Saint Louis, MO, USA
Abstract. This study investigates the improvement of ozone (O3) simulations in the Mexico City basin using a three-dimensional variational (3DVAR) data assimilation system in meteorological modeling during the MCMA-2003 campaign. Meteorological simulations from the Penn State/NCAR mesoscale model (MM5) are used to drive photochemical modeling with the Comprehensive Air Quality Model with extensions (CAMx) during a four-day episode on 13–16 April 2003. The calculated wind circulation, temperature, and humidity fields in the basin with the data assimilation are found to be more consistent with the observations than those from the reference deterministic forecast. This leads to improved calculations of plume position, peak O3 timing, and peak O3 concentrations in the photochemical model. The improvement of O3 simulations is especially strong during the daytime. The results demonstrate the importance of applying data assimilation in meteorological simulations for air quality studies in the Mexico City basin.