Evaluation of WRF mesoscale simulations and particle trajectory analysis for the MILAGRO field campaign 1Department of Earth and Atmospheric Sciences, Saint Louis University, MO, USA
2Molina Center for Energy and the Environment, CA, USA
3Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, MA, USA
Received: 04 Dec 2008 – Published in Atmos. Chem. Phys. Discuss.: 23 Jan 2009 – Published: 07 Jul 2009Abstract. Accurate numerical simulations of the complex wind flows in the Mexico
City Metropolitan Area (MCMA) can be an invaluable tool for interpreting
the MILAGRO field campaign results. This paper uses three methods
to evaluate numerical simulations of basin meteorology using the MM5 and WRF models:
statistical comparisons with observations, "Concentration Field Analysis" (CFA) using measured
air pollutant concentrations, and comparison of flow features using cluster analysis.
CFA is shown to be a better indication of simulation quality
than statistical metrics, and WRF simulations are shown to
be an improvement on the MM5 ones. Comparisons with clusters identifies
an under-representation of the drainage flows into the basin and
an over-representation of wind shear in the boundary layer.
Particle trajectories simulated with WRF-FLEXPART are then used to
analyse the transport of the urban plume and show rapid venting
and limited recirculation during MILAGRO. Lagrangian impacts were
identified at the campaign supersites, and age spectra of the pollutants
evaluated at those same sites. The evaluation presented in the
paper show that mesoscale meteorological simulations are of sufficient
accuracy to be useful for MILAGRO data analysis.
Citation: de Foy, B., Zavala, M., Bei, N., and Molina, L. T.: Evaluation of WRF mesoscale simulations and particle trajectory analysis for the MILAGRO field campaign, Atmos. Chem. Phys., 9, 4419-4438, doi:10.5194/acp-9-4419-2009, 2009.