Browne, E. C.Perring, A. E.Wooldridge, P. J.Apel, E.Hall, S. R.Huey, L. G.Mao, J.Spencer, K.M.St. Clair, JasonWeinheimer, A. J.Wisthaler, A.Cohen, R. C.2020-06-182020-06-182011-05-06Browne, E. C., Perring, A. E., Wooldridge, P. J., Apel, E., Hall, S. R., Huey, L. G., Mao, J., Spencer, K. M., Clair, J. M. St., Weinheimer, A. J., Wisthaler, A., and Cohen, R. C.: Global and regional effects of the photochemistry of CH₃O₂NO₂: evidence from ARCTAS, Atmos. Chem. Phys., 11, 4209–4219, https://doi.org/10.5194/acp-11-4209-2011, 2011.https://doi.org/10.5194/acp-11-4209-2011http://hdl.handle.net/11603/18925Using measurements from the NASA Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS) experiment, we show that methyl peroxy nitrate (CH₃O₂NO₂) is present in concentrations of ~5–15 pptv in the springtime arctic upper troposphere. We investigate the regional and global effects of CH₃O₂NO₂ by including its chemistry in the GEOS-Chem 3-D global chemical transport model. We find that at temperatures below 240 K inclusion of CH₃O₂NO₂ chemistry results in decreases of up to ~20 % in NOₓ, ~20 % in N₂O₅, ~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 NOₓ at low temperatures, CH₃O₂NO₂ decreases the cycling of HO₂ to OH, resulting in a larger upper tropospheric HO₂ to OH ratio. These results may impact some estimates of lightning NOₓ sources as well as help explain differences between models and measurements of upper tropospheric composition.11 pagesen-USThis item is likely protected under Title 17 of the U.S. Copyright Law. Unless on a Creative Commons license, for uses protected by Copyright Law, contact the copyright holder or the author.Attribution 3.0 UnportedText