Using 3DVAR data assimilation system to improve ozone simulations in the Mexico City basin N. Bei1,2, B. de Foy1,3, W. Lei1,2, M. Zavala1,2, and L. T. Molina1,2 1Molina Center for Energy and the Environment, La Jolla, CA, USA 2Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, 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 simulations during the MCMA-2003 field measurement campaign.
Meteorological simulations from the NCAR/Penn State mesoscale model (MM5)
are used to drive photochemical simulations with the Comprehensive Air
Quality Model with extensions (CAMx) during a four-day episode on 13–16
April 2003. The simulated 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 simulations of plume position, peak O3 timing, and
peak O3 concentrations in the photochemical model. The improvement in
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.
Citation: Bei, N., de Foy, B., Lei, W., Zavala, M., and Molina, L. T.: Using 3DVAR data assimilation system to improve ozone simulations in the Mexico City basin, Atmos. Chem. Phys., 8, 7353-7366, doi:10.5194/acp-8-7353-2008, 2008.