Global and regional effects of the photochemistry of CH_3O_2NO_2: evidence from ARCTAS

• Published in: Atmospheric Chemistry and Physics
• Main Authors: Browne, E. C., Perring, A. E., Wooldridge, P. J., Apel, E., Hall, S. R., Huey, L. G., Mao, J., Spencer, K. M., St. Clair, J. M., Weinheimer, A. J., Wisthaler, A., Cohen, R. C.
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Copernicus Publications 2011
• Subjects: Arctic; Brune
• Online Access: https://doi.org/10.5194/acp-11-4209-2011

Using measurements from the NASA Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS) experiment, we show that methyl peroxy nitrate (CH_3O_2NO_2) is present in concentrations of ~5–15 pptv in the springtime arctic upper troposphere. We investigate the regional and global effects of CH_3O_2NO_2 by including its chemistry in the GEOS-Chem 3-D global chemical transport model. We find that at temperatures below 240 K inclusion of CH_3O_2NO_2 chemistry results in decreases of up to ~20 % in NO_x, ~20 % in N_2O_5, ~5 % in HNO3, ~2 % in ozone, and increases in methyl hydrogen peroxide of up to ~14 %. Larger changes are observed in biomass burning plumes lofted to high altitude. Additionally, by sequestering NO_x at low temperatures, CH_3O_2NO_2 decreases the cycling of HO_2 to OH, resulting in a larger upper tropospheric HO_2 to OH ratio. These results may impact some estimates of lightning NO_x sources as well as help explain differences between models and measurements of upper tropospheric composition. © 2011 Author(s). Published by Copernicus Publications on behalf of the European Geosciences Union. This work is distributed under the Creative Commons Attribution 3.0 License. Received: 20 December 2010. Published in Atmos. Chem. Phys. Discuss.: 21 January 2011. Revised: 27 April 2011. Accepted: 28 April 2011. Published: 6 May 2011. The analysis described here was funded by NASA grant NNX08AE56G and a NASA Earth Systems Science Fellowship to ECB. Acetone measurements were supported by the Austrian Research Promotion Agency (FFG-ALR) and the Tiroler Zukunftstiftung and carried out with the help/support of T. Mikoviny, M. Graus, A. Hansel and T. D. Maerk. We thank William H. Brune for use of the OH and HO2 measurements, Glenn Diskin for use of the methane and water measurements, and John D. Crounse and Paul O. Wennberg for the use of California Institute of Technology CIMS data. We also thank the ground and flight crews of the DC-8 for their hard work and logistical support ...