Articles | Volume 15, issue 11
Atmos. Chem. Phys., 15, 6047–6068, 2015

Special issue: POLARCAT (Polar Study using Aircraft, Remote Sensing, Surface...

Atmos. Chem. Phys., 15, 6047–6068, 2015
Research article
03 Jun 2015
Research article | 03 Jun 2015

Biomass burning influence on high-latitude tropospheric ozone and reactive nitrogen in summer 2008: a multi-model analysis based on POLMIP simulations

S. R. Arnold1, L. K. Emmons2, S. A. Monks1, K. S. Law3, D. A. Ridley4, S. Turquety5, S. Tilmes2, J. L. Thomas3, I. Bouarar3, J. Flemming6, V. Huijnen7, J. Mao8, B. N. Duncan9, S. Steenrod9, Y. Yoshida9, J. Langner10, and Y. Long5 S. R. Arnold et al.
  • 1Institute for Climate and Atmospheric Science, School of Earth & Environment, University of Leeds, UK
  • 2Atmospheric Chemistry Division, NCAR, Boulder, CO, USA
  • 3UPMC Univ. Paris 06, Université Versailles St-Quentin; CNRS/INSU, UMR 8190, Paris, France
  • 4Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
  • 5Laboratoire de Météorologie Dynamique, IPSL, CNRS, UMR8539, 91128 Palaiseau CEDEX, France
  • 6ECMWF, Reading, UK
  • 7Royal Netherlands Meteorological Institute (KNMI), De Bilt, the Netherlands
  • 8Program in Atmospheric and Oceanic Sciences, Princeton University and Geophysical Fluid Dynamics Laboratory/National Oceanic and Atmospheric Administration, Princeton, NJ, USA
  • 9NASA Goddard Space Flight Center, Greenbelt, MD, USA
  • 10Swedish Meteorological and Hydrological Institute, 60176 Norrköping, Sweden

Abstract. We have evaluated tropospheric ozone enhancement in air dominated by biomass burning emissions at high latitudes (> 50° N) in July 2008, using 10 global chemical transport model simulations from the POLMIP multi-model comparison exercise. In model air masses dominated by fire emissions, ΔO3/ΔCO values ranged between 0.039 and 0.196 ppbv ppbv−1 (mean: 0.113 ppbv ppbv−1) in freshly fire-influenced air, and between 0.140 and 0.261 ppbv ppbv−1 (mean: 0.193 ppbv) in more aged fire-influenced air. These values are in broad agreement with the range of observational estimates from the literature. Model ΔPAN/ΔCO enhancement ratios show distinct groupings according to the meteorological data used to drive the models. ECMWF-forced models produce larger ΔPAN/ΔCO values (4.47 to 7.00 pptv ppbv−1) than GEOS5-forced models (1.87 to 3.28 pptv ppbv−1), which we show is likely linked to differences in efficiency of vertical transport during poleward export from mid-latitude source regions. Simulations of a large plume of biomass burning and anthropogenic emissions exported from towards the Arctic using a Lagrangian chemical transport model show that 4-day net ozone change in the plume is sensitive to differences in plume chemical composition and plume vertical position among the POLMIP models. In particular, Arctic ozone evolution in the plume is highly sensitive to initial concentrations of PAN, as well as oxygenated VOCs (acetone, acetaldehyde), due to their role in producing the peroxyacetyl radical PAN precursor. Vertical displacement is also important due to its effects on the stability of PAN, and subsequent effect on NOx abundance. In plumes where net ozone production is limited, we find that the lifetime of ozone in the plume is sensitive to hydrogen peroxide loading, due to the production of HOx from peroxide photolysis, and the key role of HO2 + O3 in controlling ozone loss. Overall, our results suggest that emissions from biomass burning lead to large-scale photochemical enhancement in high-latitude tropospheric ozone during summer.

Short summary
The extent to which forest fires produce the air pollutant and greenhouse gas ozone (O3) in the atmosphere at high latitudes in not well understood. We have compared how fire emissions produce O3 and its precursors in several models of atmospheric chemistry. We find enhancements in O3 in air dominated by fires in all models, which increase on average as fire emissions age. We also find that in situ O3 production in the Arctic is sensitive to details of organic chemistry and vertical lifting.
Final-revised paper