Air Quality Simulation with WRF-Chem Over Southeastern Brazil, Part I: Model Description and Evaluation Using Ground-Based and Satellite Data

Abstract

A comprehensive WRF-Chem model evaluation is conducted using ground-based and total column observational data from air quality stations and satellite retrievals. PM2.5, NOx (NO + NO2), CO, O3 concentrations and AOD values over southeastern Brazil were analyzed to assess the model's capability in reproducing atmospheric observation. Good agreement between model simulations and observations for meteorological parameters was found in most periods. Model simulations of PM2.5, NOx, CO and O3 agreed well with ground-based observations in terms of temporal variations and trends, with model-observation discrepancies due to uncertainties in the emission inventories. O3 was the better simulated pollutant in terms of temporal variability. Moderate and high correlation coefficients (ranging 0.46 - 0.81) were found for tropospheric NO2 VCD and CO column, and AOD at 550nm due to also uncertainties in the emission inventories and aerosol model simplifications. This work represents a first effort, in southeastern Brazil, that combines numerical modeling, remote sensing and ground-based stations to analyze and understand the impact exerted by the emissions of urban pollution over surrounding areas. A more in-depth analysis of the impact of emissions transport to inland regions from urban areas in southeastern Brazil will be discussed in the second part of this work.

Keywords: Air pollution, WRF-Chem model, Air Quality station, AERONET, satellite products.