Articles | Volume 13, issue 20
Atmos. Chem. Phys., 13, 10227–10241, 2013

Special issue: Quantifying the impact of Boreal fires on tropospheric oxidants...

Atmos. Chem. Phys., 13, 10227–10241, 2013

Research article 18 Oct 2013

Research article | 18 Oct 2013

Investigation of CO, C2H6 and aerosols in a boreal fire plume over eastern Canada during BORTAS 2011 using ground- and satellite-based observations and model simulations

D. Griffin1, K. A. Walker2,1, J. E. Franklin3, M. Parrington4,*, C. Whaley1, J. Hopper3, J. R. Drummond3, P. I. Palmer4, K. Strong1, T. J. Duck3, I. Abboud5, P. F. Bernath7,6, C. Clerbaux9,8, P.-F. Coheur9, K. R. Curry3, L. Dan1, E. Hyer10, J. Kliever1, G. Lesins3, M. Maurice1, A. Saha11, K. Tereszchuk7, and D. Weaver1 D. Griffin et al.
  • 1Department of Physics, University of Toronto, Toronto, Ontario M5S 1A7, Canada
  • 2Department of Chemistry, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
  • 3Department of Physics and Atmospheric Science, Dalhousie University, Halifax, Nova Scotia B3H 1Z9, Canada
  • 4School of GeoSciences, The University of Edinburgh, Edinburgh EH9 3JN, UK
  • 5AEROCAN, Environment Canada, Egbert, Ontario L0L 1N0, Canada
  • 6Department of Chemistry and Biochemistry, Old Dominion University, Norfolk, Virginia 23529, USA
  • 7Department of Chemistry, University of York, Heslington, York YO10 5DD, UK
  • 8UPMC Univ. Paris 06, Université Versailles St.-Quentin, CNRS/INSU, LATMOS-IPSL, Paris, France
  • 9Spectroscopie de l'atmosphère, Chimie Quantique et Photophysique, Université Libre de Bruxelles, Brussels, Belgium
  • 10Marine Meteorology Division, Naval Research Laboratory, Monterey, California 93943, USA
  • 11CARTEL, Université de Sherbrooke, 2500, boulevard de l'Université, Sherbrooke, Québec J1K 2R1, Canada
  • *now at: European Centre for Medium-Range Weather Forecasts, Shinfield Park, Reading, RG2 9AX, UK

Abstract. We present the results of total column measurements of CO, C2H6 and fine-mode aerosol optical depth (AOD) during the "Quantifying the impact of BOReal forest fires on Tropospheric oxidants over the Atlantic using Aircraft and Satellites" (BORTAS-B) campaign over eastern Canada. Ground-based observations, using Fourier transform spectrometers (FTSs) and sun photometers, were carried out in July and August 2011. These measurements were taken in Halifax, Nova Scotia, which is an ideal location to monitor the outflow of boreal fires from North America, and also in Toronto, Ontario. Measurements of fine-mode AOD enhancements were highly correlated with enhancements in coincident trace gas (CO and C2H6) observations between 19 and 21 July 2011, which is typical for a smoke plume event. In this paper, we focus on the identification of the origin and the transport of this smoke plume. We use back trajectories calculated by the Canadian Meteorological Centre as well as FLEXPART forward trajectories to demonstrate that the enhanced CO, C2H6 and fine-mode AOD seen near Halifax and Toronto originated from forest fires in northwestern Ontario that occurred between 17 and 19 July 2011. In addition, total column measurements of CO from the satellite-borne Infrared Atmospheric Sounding Interferometer (IASI) have been used to trace the smoke plume and to confirm the origin of the CO enhancement. Furthermore, the enhancement ratio – that is, in this case equivalent to the emission ratio (ERC2H6/CO) – was estimated from these ground-based observations. These C2H6 emission results from boreal fires in northwestern Ontario agree well with C2H6 emission measurements from other boreal regions, and are relatively high compared to fires from other geographical regions. The ground-based CO and C2H6 observations were compared with outputs from the 3-D global chemical transport model GEOS-Chem, using the Fire Locating And Modeling of Burning Emissions (FLAMBE) inventory. Agreement within the stated measurement uncertainty (~3% for CO and ~8% for C2H6) was found for the magnitude of the enhancement of the CO and C2H6 total columns between the measured and modelled results. However, there is a small shift in time (of approximately 6 h) of arrival of the plume over Halifax between the results.

Final-revised paper