Analysis of tropospheric ozone and carbon monoxide profiles over South America based on MOZAIC/IAGOS database and model simulations

Abstract

We analysed ozone and carbon monoxide profiles measured by commercial aircrafts from the MOZAIC/IAGOS fleet, during ascending and descending flights over Caracas, in Venezuela, from August 1994 to December 2009, over Rio de Janeiro, from 1994 to 2004 and from July 2012 to June 2013, and over São Paulo, in Brazil, from August 1994 to 2005. For ozone, results showed a clean atmosphere over Caracas presenting the highest seasonal mean in March, April and May. Backward trajectory analyses with FLEXPART, of case studies for which the measured concentrations were high, showed that contributions from local, Central and North America, the Caribbean and Africa either from anthropogenic emissions, biomass burning or lightning were possible. Satellite products as fire counts from MODIS, lightning flash rates from LIS, and CO and O₃ from Infrared Atmospheric Sounding Interferometer and wind maps at different levels helped corroborate previous findings. Sensitivity studies performed with the chemical transport model GEOS-Chem captured the effect of anthropogenic emissions but underestimated the influence of biomass burning, which could be due to an underestimation of GFEDv2 emission inventory. The model detected the contribution of lightning from Africa in JJA and SON and from South America in DJF, possibly from the northeast of Brazil. Over São Paulo and Rio de Janeiro, GEOS-Chem captured the seasonal variability of lightning produced in South America and attributed this source as the most important in this region, except in JJA, when anthropogenic emissions were addressed as the more impacting source of ozone precursors. However, comparison with the measurements indicated that the model overestimated ozone formation, which could be due to the convective parameterisation or the stratospheric influence. The highest ozone concentration was observed during September to November, but the model attributed only a small influence of biomass burning from South America, with no contribution of long-range transport from Africa.

• tropospheric ozone
• carbon monoxide
• MOZAIC/IAGOS
• air pollution
• GEOS-Chem
• FLEXPART
• South America
• biomass burning
• IASI

This paper is part of a Special Issue on MOZAIC-IAGOS in Tellus B celebrating 20 years of an ongoing air chemistry climate research measurements from airbus commerical aircraft operated by an international consortium of countries. More papers from this issue can be found at http://www.tellusb.net

This paper is part of a Special Issue on MOZAIC-IAGOS in Tellus B celebrating 20 years of an ongoing air chemistry climate research measurements from airbus commerical aircraft operated by an international consortium of countries. More papers from this issue can be found at http://www.tellusb.net

Acknowledgements

The authors acknowledge the support of the European Commission to the MOZAIC project (1994–2003) and the preparatory phase of IAGOS (2005–2012), Airbus and the Airlines (Lufthansa, Air-France, Austrian, Air Namibia, Cathay Pacific and China Airlines so far) for carrying the MOZAIC or IAGOS equipment and for performing the maintenance since 1994. MOZAIC is presently funded by INSU-CNRS (France), Météo-France, CNES, Université Paul Sabatier (Toulouse, France) and Research Center Jülich (FZJ, Jülich, Germany). The MOZAIC-IAGOS data are available at www.pole-ether.fr, thanks to the support from ETHER, French data centre service. M.A. Yamasoe thanks Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) and Ciências sem Fronteira Program for grant number 237032/2012-0, and Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES). She also acknowledges all the staff from the Laboratoire d'Aérologie for the help during her visit. The Lightning Imaging Sensor (LIS) Science Data were obtained from the NASA EOSDIS Global Hydrology Resource Center (GHRC) DAAC, Huntsville, AL, www.thunder.nsstc.nasa.gov/. Fire counts from MODIS (Moderate Resolution Imaging Spectroradiometer) on board Terra satellite were obtained using Mirador Earth Science Data Search Tool, www.mirador.gsfc.nasa.gov/. Thanks to the European Centre for Medium-Range Weather Forecasts (ECMWF) for making available the Global Reanalysis ERA Interim data at www.apps.ecmwf.int/datasets/data/interim_full_moda/. Finally, we acknowledge the anonymous referees for their time and thorough review of the manuscript and their constructive suggestions.

Notes

This paper is part of a Special Issue on MOZAIC-IAGOS in Tellus B celebrating 20 years of an ongoing air chemistry climate research measurements from airbus commerical aircraft operated by an international consortium of countries. More papers from this issue can be found at http://www.tellusb.net