References

ACP

Atmospheric Chemistry and Physics

ACP

1680-7324

Copernicus GmbH

Göttingen, Germany

10.5194/acp-11-13181-2011

Reactive nitrogen, ozone and ozone production in the Arctic troposphere and the impact of stratosphere-troposphere exchange

Liang

¹ ¹¹ ¹² Rodriguez

J. M.

¹ Douglass

A. R.

¹ Crawford

J. H.

² Olson

J. R.

² Apel

³ Bian

¹ ⁴ Blake

D. R.

⁵ Brune

⁶ Chin

¹ Colarco

P. R.

¹ da Silva

⁷ Diskin

G. S.

² Duncan

B. N.

¹ Huey

L. G.

⁸ Knapp

D. J.

³ Montzka

D. D.

³ Nielsen

J. E.

⁷ ⁹ Pawson

⁷ Riemer

D. D.

³ Weinheimer

A. J.

³ Wisthaler

¹⁰

NASA Goddard Space Flight Center, Atmospheric Chemistry and Dynamics Branch, Code 613.3, Greenbelt, MD 20771, USA

NASA Langley Research Center, Hampton, VA 23681-2199, USA

National Center for Atmospheric Research, 1850 Table Mesa Dr., Boulder, CO 80307, USA

Joint Center for Environmental Technology, University of Maryland, Baltimore County, Maryland, USA

University of California, 570 Rowland Hall, Irvine, CA 92697, USA

Department of Meteorology, Pennsylvania State University, University Park, PA 16802, USA

NASA Goddard Space Flight Center, Global Modeling and Assimilation Office, Code 610.1, Greenbelt, MD 20771, USA

School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA 30332, USA

Science Systems and Applications Inc., Lanham, Maryland, USA

Institute for Ion Physics & Applied Physics, University of Innsbruck, 6020 Innsbruck, Austria

formerly at: Goddard Earth Sciences & Technology Center, University of Maryland, Baltimore County, Maryland, USA

currently at: Universities Space Research Association, GESTAR, Columbia, Maryland, USA

21 12 2011

11 24 13181 13199

This is an open-access article ditributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

This article is available from http://www.atmos-chem-phys.net/11/13181/2011/acp-11-13181-2011.html

The full text article is available as a PDF file from http://www.atmos-chem-phys.net/11/13181/2011/acp-11-13181-2011.pdf

We use aircraft observations obtained during the Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS) mission to examine the distributions and source attributions of O3 and NOy in the Arctic and sub-Arctic region. Using a number of marker tracers, we distinguish various air masses from the background troposphere and examine their contributions to NOx, O3, and O3 production in the Arctic troposphere. The background Arctic troposphere has a mean O3 of ~60 ppbv and NOx of ~25 pptv throughout spring and summer with CO decreasing from ~145 ppbv in spring to ~100 ppbv in summer. These observed mixing ratios are not notably different from the values measured during the 1988 ABLE-3A and the 2002 TOPSE field campaigns despite the significant changes in emissions and stratospheric ozone layer in the past two decades that influence Arctic tropospheric composition. Air masses associated with stratosphere-troposphere exchange are present throughout the mid and upper troposphere during spring and summer. These air masses, with mean O3 concentrations of 140–160 ppbv, are significant direct sources of O3 in the Arctic troposphere. In addition, air of stratospheric origin displays net O3 formation in the Arctic due to its sustainable, high NOx (75 pptv in spring and 110 pptv in summer) and NOy (~800 pptv in spring and ~1100 pptv in summer). The air masses influenced by the stratosphere sampled during ARCTAS-B also show conversion of HNO3 to PAN. This active production of PAN is the result of increased degradation of ethane in the stratosphere-troposphere mixed air mass to form CH3CHO, followed by subsequent formation of PAN under high NOx conditions. These findings imply that an adequate representation of stratospheric NOy input, in addition to stratospheric O3 influx, is essential to accurately simulate tropospheric Arctic O3, NOx and PAN in chemistry transport models. Plumes influenced by recent anthropogenic and biomass burning emissions observed during ARCTAS show highly elevated levels of hydrocarbons and NOy (mostly in the form of NOx and PAN), but do not contain O3 higher than that in the Arctic tropospheric background except some aged biomass burning plumes sampled during spring. Convection and/or lightning influences are negligible sources of O3 in the Arctic troposphere but can have significant impacts in the upper troposphere in the continental sub-Arctic during summer.

References 1

Allen, D. J., Dibb, J. E., Ridley, B., Pickering, K. E., and Talbot, R.W.: An estimate of the stratospheric contribution to springtime tropospheric ozone maxima using TOPSE measurements and beryllium-7 simulations, J. Geophys. Res., 108, 8355, http://dx.doi.org/10.1029/2001JD001428doi:10.1029/2001JD001428, 2003.

Alvarado, M. J., Logan, J. A., Mao, J., Apel, E., Riemer, D., Blake, D., Cohen, R. C., Min, K.-E., Perring, A. E., Browne, E. C., Wooldridge, P. J., Diskin, G. S., Sachse, G. W., Fuelberg, H., Sessions, W. R., Harrigan, D. L., Huey, G., Liao, J., Case-Hanks, A., Jimenez, J. L., Cubison, M. J., Vay, S. A., Weinheimer, A. J., Knapp, D. J., Montzka, D. D., Flocke, F. M., Pollack, I. B., Wennberg, P. O., Kurten, A., Crounse, J., Clair, J. M. St., Wisthaler, A., Mikoviny, T., Yantosca, R. M., Carouge, C. C., and Le Sager, P.: Nitrogen oxides and PAN in plumes from boreal fires during ARCTAS-B and their impact on ozone: an integrated analysis of aircraft and satellite observations, Atmos. Chem. Phys., 10, 9739–9760, http://dx.doi.org/10.5194/acp-10-9739-2010doi:10.5194/acp-10-9739-2010, 2010.

Apel, E. C, Hills, A. J., Lueb, R., Zindel, S., Eisele, S., and Riemer, D. D.: A fast-GC/MS system to measure C-2 to C-4 carbonyls and methanol aboard aircraft, J. Geophys. Res., 108, 8794, http://dx.doi.org/10.1029/2002JD003199doi:10.1029/2002JD003199, 2003.

Atlas, E. L., Ridley, B. A., and Cantrell, C. A.: The Tropospheric Ozone Production about the Spring Equinox (TOPSE) Experiment: Introduction, J. Geophys. Res., 108, 8353, http://dx.doi.org/10.1029/2002JD003172doi:10.1029/2002JD003172, 2003.

Beine, H. J., Jaffe, D. A., Herring, J. A., Kelley, J. A., Krognes, T., and Stordal, F.: High-Latitude Springtime Photochemistry. Part I: NOx, PAN and Ozone Relationships, J. Atmos. Chem., 27, 127–153, 1997.

Blake, N. J., Blake, D. R., Simpson, I. J., Meinardi, S., Swanson, A. L., Lopez, J. P., Katzenstein, A. S., Barletta, B., Shirai, T., Atlas, E., Sachse, G., Avery, M., Vay., S., Fuelberg, H. E., Kiley, C. M., Kita, K., and Rowland, F. S.: NMHCs and halocarbons in Asian continental outflow during the Transport and Chemical Evolution over the Pacific (TRACE-P) field campaign: comparison with PEM-West B, J. Geophys. Res., 108, 8806, http://dx.doi.org/10.1029/2002JD003367doi:10.1029/2002JD003367, 2003.

Brune, W. H., Tan, D., Faloona, I. F., Jaeglé, L., Jacob, D. J., Heikes, B. G., Snow, J., Kondo, Y., Shetter, R., Sachse, G. W., Anderson, B., Gregory, G. L., Vay, S., Singh, H. B., Davis, D. D., Crawford, J. H., and Blake, D. R.: OH and HO2 chemistry in the North Atlantic free troposphere, Geophys. Res. Lett., 26, 3077–3080, 1999.

Cleary, P. A., Wooldridge, P. J., and Cohen, R. C.: Laser-induced fluorescence detection of atmospheric NO2 using a commercial diode laser and a supersonic expansion, Appl. Opt., 41, 6950–6956, 2002.

Crounse, J., McKinney, K. A., Kwan, A. J., and Wennberg, P. O.: Measurement of gas-phase hydroperoxides by chemical ionization mass spectrometry, Anal. Chem., 78, 6726–6732, 2006.

Dibb, J. E., Talbot, R. W., Scheuer, E., Seid, G., DeBell, L., Lefer, B., and Ridley, B.: Stratospheric influence on the northern North American free troposphere during TOPSE: 7Be as a stratospheric tracer, J. Geophys. Res., 108, 8363, http://dx.doi.org/10.1029/2001JD001347doi:10.1029/2001JD001347, 2003.

Diskin, G. S., Podolske, J. R., Sachse, G. W., and Slate, T. A.: Open-Path Airborne Tunable Diode Laser Hygrometer, in Diode Lasers and Applications in Atmospheric Sensing, SPIE Proceedings 4817, edited by: Fried, A., 196–204, 2002.

Duncan, B. N., Bey, I., Chin, M., Mickley, L. J., Fairlie, T. D., Martin, R. V., and Matsueda, H.: Indonesian wildfires of 1997: Impact on tropospheric chemistry, J. Geophys. Res., 108, 4458, http://dx.doi.org/10.1029/2002JD003195doi:10.1029/2002JD003195, 2003.

Esler, J. G., Tan, D. G. H., Haynes, P. H., Evans, M. J., Law, K. S., Plantevin, P.-H., and Pyle, J. A.: Stratosphere-troposphere exchange: Chemical sensitivity to mixing, J. Geophys. Res., 106, 4717–4731, http://dx.doi.org/10.1029/2000JD900405doi:10.1029/2000JD900405, 2001.

Fisher, J. A., Jacob, D. J., Purdy, M. T., Kopacz, M., Le Sager, P., Carouge, C., Holmes, C. D., Yantosca, R. M., Batchelor, R. L., Strong, K., Diskin, G. S., Fuelberg, H. E., Holloway, J. S., Hyer, E. J., McMillan, W. W., Warner, J., Streets, D. G., Zhang, Q., Wang, Y., and Wu, S.: Source attribution and interannual variability of Arctic pollution in spring constrained by aircraft (ARCTAS, ARCPAC) and satellite (AIRS) observations of carbon monoxide, Atmos. Chem. Phys., 10, 977–996, http://dx.doi.org/10.5194/acp-10-977-2010doi:10.5194/acp-10-977-2010, 2010.

Hansen, J., Sato, M., and Ruedy, R.: Radiative forcing and climate response, J. Geophys. Res., 102, 6831–6864, http://dx.doi.org/10.1029/96JD03436doi:10.1029/96JD03436, 1997.

Harriss, R. C., Wofsy, S. C., Bartlett, D. S., Shipham, M. C., Jacob, D. J., Hoell, J. M., Bendura, R. J., Drewry, J. W., McNeal, R. J., Navarro, R. L., Gidge, R. N., and Babine, V. E.: The Arctic Boundary Layer Expedition (ABLE-3A): July-August 1988, J. Geophys. Res., 97, 16383–16394, 1992.

Holton, J. R., Haynes, P. H., McIntyre, M. E., Douglass, A. R., Rood, R. B., and Pfister, L.: Stratosphere-troposphere exchange, Rev. Geophys., 33, 403–439, 1995.

Holzinger, R., Jordan, A., Hansel, A., and Lindinger, W.: Automobile emissions of acetonitrile: Assessments of its contribution to the global source, Atmos. Environ., 38, 187–193, 2001.

Honrath, R. E., Hamlin, A. J., and Merrill, J. T.: Transport of ozone precursors from the Arctic troposphere to the North Atlantic region, J. Geophys. Res., 101, 29335–29351, 1996.

IPCC Fourth Assessment Report, Climate Change 2007, IPCC, Geneva, Switzerland.

Jacob, D. J.: Introduction to Atmospheric Chemistry, Princeton University Press, p 240, 1999.

Jacob, D. J., Crawford, J. H., Maring, H., Clarke, A. D., Dibb, J. E., Emmons, L. K., Ferrare, R. A., Hostetler, C. A., Russell, P. B., Singh, H. B., Thompson, A. M., Shaw, G. E., McCauley, E., Pederson, J. R., and Fisher, J. A.: The Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS) mission: design, execution, and first results, Atmos. Chem. Phys., 10, 5191–5212, http://dx.doi.org/10.5194/acp-10-5191-2010doi:10.5194/acp-10-5191-2010, 2010.

Jacob, D. J., Wofsy, S. C., Bakwin, P. S., Fan, S.-M., Harriss, R. C., Talbot, R. W., Bradshaw, J. D., Sandholm, S. T., Singh, H. B., Browell, E. V., Gregory, G. L., Sachse, G. W., Shipham, M. C., Blake, D. R., and Fitzjarrald, D. R.: Summertime photochemistry at high northern latitudes, J. Geophys. Res., 97, 16421–16431, 1992.

Jaeglé, L., Jacob, D. J., Brune, W. H., Tan, D., Faloona, I. C., Weinheimer, A. J., Ridley, B. A., Campos, T. L., and Sachse, G. W.: Sources of HOx and production of ozone in the upper troposphere over the United States, Geophys. Res. Lett., 25, 1709–1712, 1998.

Klonecki, A. A. and Hevy II, H.: Tropospheric chemical ozone tendencies in the CO-CH4-NOy-H2O system: Their sensitivity to variations in environmental parameters and their application to a GCTM study, J. Geophys. Res., 102, 21221–21237, 1997.

Law, K. S. and Stohl, A.: Arctic Air Pollution: Origins and Impacts, Science, 315, 1537, http://dx.doi.org/10.1126/science.1137695doi:10.1126/science.1137695, 2007.

Levy II, H., Moxim, W. J., Klonecki, A. A., and Kasibhatla, P. S.: Simulated tropospheric NOx: Its evaluation, global distribution and individual source contributions, J. Geophys. Res., 104, 26279–26306, 1999.

Liang, Q., Jaeglé, L., Hudman, R. C., Turquety, S., Jacob, D. J., Avery, M. A., Browell, E. V., Sachse, G. W., Blake, D. R., Brune, W., Ren, X., Cohen, R. C., Fried, A., Fuelberg, H., Porter, M., Heikes, B. G., Huey, G., Singh, H. B., and Wennberg, P. O.: Summertime influence of Asian pollution in the free troposphere over North America, J. Geophys. Res., 112, D12S11, http://dx.doi.org/10.1029/2006JD007919doi:10.1029/2006JD007919, 2007.

Liang, Q., Stolarski, R. S., Douglass, A. R., Newman, P. A., and Nielsen, J. E.: Evaluation of emissions and transport of CFCs using surface observations and their seasonal cycles and the GEOS CCM simulation with emissions-based forcing, J. Geophys. Res., 113, D14302, http://dx.doi.org/10.1029/2007JD009617doi:10.1029/2007JD009617, 2008.

Liang, Q., Douglass, A. R., Duncan, B. N., Stolarski, R. S., and Witte, J. C.: The governing processes and timescales of stratosphere-to-troposphere transport and its contribution to ozone in the Arctic troposphere, Atmos. Chem. Phys., 9, 3011–3025, http://dx.doi.org/10.5194/acp-9-3011-2009doi:10.5194/acp-9-3011-2009, 2009.

Lin, X., Trainer, M., and Liu, S. C.: On the nonlinearity of the tropospheric ozone production, J. Geophys. Res., 93, 15879–15888, 1988.

Lobert, J. M., Scharffe, D. H., Hao, W. M., and Crutzen, P. J.: Importance of biomass burning in the atmospheric budgets of nitrogen-containing gases, Nature, 346, 552–554, 1990.

Mauzerall, D. L, Logan, J. A., Jacob, D. J., Anderson, B. E., Blake, D. R., Bradshaw, J. D., Heikes, B., Sachse, G. W., Singh, S., and Talbot, R.: Photochemistry in biomass burning plumes and implications for tropospheric ozone over the tropical South Atlantic, J. Geophys. Res., 103, 8401–8423, 1998.

Moxim, W. J., Levy, H., and Kasibhalta, P. S.: Simulated global tropopsheric PAN: its transport and impact on NOx, J. Geophys. Res., 101, 12621–12638, 1996.

Neuman, J. A., Nowak, J. B., Huey, L. G., Burkholder, J. B., Dibb, J. E., Holloway, J. S., Liao, J., Peischl, J., Roberts, J. M., Ryerson, T. B., Scheuer, E., Stark, H., Stickel, R. E., Tanner, D. J., and Weinheimer, A.: Bromine measurements in ozone depleted air over the Arctic Ocean, Atmos. Chem. Phys., 10, 6503–6514, http://dx.doi.org/10.5194/acp-10-6503-2010doi:10.5194/acp-10-6503-2010, 2010.

Olson, J. R., Crawford, J. H., Chen, G., Fried, A., Evans, M. J., Jordan, C. E., Sandholm, S. T., Davis, D. D., Anderson, B. E., Avery, M. A., Barrick, J. D., Blake, D. R., Brune, W. H., Eisele, F. L., Flocke, F., Harder, H., Jacob, D. J., Kondo, Y., Lefer, B. L., Martinez, M., Mauldin, R. L., Sachse, G. W., Shetter, R. E., Singh, H. B., Talbot, R. W., and Tan, D.: Testing fast phototochemical theory during TRACE-P based on measurements of OH, HO2, and CH2O,J. Geophys. Res., 109, D15S10, http://dx.doi.org/10.1029/2003JD004278doi:10.1029/2003JD004278, 2004.

Paris, J.-D., Stohl, A., N�d�lec, P., Arshinov, M. Yu., Panchenko, M. V., Shmargunov, V. P., Law, K. S., Belan, B. D., and Ciais, P.: Wildfire smoke in the Siberian Arctic in summer: source characterization and plume evolution from airborne measurements, Atmos. Chem. Phys., 9, 9315-9327, http://dx.doi.org/10.5194/acp-9-9315-2009doi:10.5194/acp-9-9315-2009, 2009.

Parrish, D. D., Trainer, M., Holloway, J. S., Yee, J. E., Warshawsky, M. D., and Fehsenfeld, F. C.: Relationships between ozone and carbon monoxide at surface sites in the North Atlantic region, J. Geophys. Res., 103, D11, http://dx.doi.org/10.1029/98JD00376doi:10.1029/98JD00376, 1998.

Penkett, S. A. and Brice, K. A.: The spring maximum in photo oxidants in northern-hemisphere troposphere, Nature, 319, 655–657, 1986.

Quinn, P. K., Bates, T. S., Baum, E., Doubleday, N., Fiore, A. M., Flanner, M., Fridlind, A., Garrett, T. J., Koch, D., Menon, S., Shindell, D., Stohl, A., and Warren, S. G.: Short-lived pollutants in the Arctic: their climate impact and possible mitigation strategies, Atmos. Chem. Phys., 8, 1723-1735, http://dx.doi.org/10.5194/acp-8-1723-2008doi:10.5194/acp-8-1723-2008, 2008.

Real, E., Law, K. S., Weinzierl, B., Fiebig, M., Petzold, A., Wild, O., Methven, J., Arnold, S., Stohl, A., Huntrieser, H., Roiger, A., Schlager, H., Stewart, D., Avery, M., Sachse, G., Browell, E., Ferrare, R., and Blake, D.: Processes influencing ozone levels in Alaskan forest fire plumes during long-range transport over the North Atlantic, J. Geophys. Res., 112, D10S41, http://dx.doi.org/10.1029/2006JD007576doi:10.1029/2006JD007576, 2007.

Singh, H. B., O'Hara, D., Herlth, D., Bradshaw, J. D., Sandholm, S. T., Gregory, G. L., Sachse, G. W., Blake, D. R., Crutzen, P. J., and Kanakidou, M. A.: Atmospheric measurements of peroxyacetyl nitrate and other organic nitrates at high latitudes: Possible sources and sinks, J. Geophys. Res., 97, 16511–16522, 1992.

Singh, H. B., Anderson, B. E., Brune, W. H., Cai, C., Cohen, R. C., Crawford, J. H., Cubison, M. J., Czech, E. P., Emmons, L., Fuelberg, H. E., Huey, G., Jacob, D. J., Jimenez, J. L., Kaduwela, A., Kondo, Y., Mao, J., Olson, J. R., Sachse, G. W., Vay, S. A., Weinheimer, A., Wennberg, P. O., and Wisthaler, A.: the ARCTAS Science Team: Pollution influences on atmospheric composition and chemistry at high northern latitudes: Boreal and California forest fire emissions, Atmos. Environ., 44, 4553–4564, 2010.

Shindell, D.: Local and remote contributions to Arctic warming, Geophys. Res. Lett., 34, L14704, http://dx.doi.org/10.1029/2007GL030221doi:10.1029/2007GL030221, 2007.

Shindell, D., Faluvegi, F., Lacis, A., Hansen, J., Ruedy, R., and Aguilar, E.: Role of tropospheric ozone increases in 20th-century climate change, J. Geophys. Res., 111, D08302, http://dx.doi.org/10.1029/2005JD006348doi:10.1029/2005JD006348, 2006.

Shindell, D. T., Chin, M., Dentener, F., Doherty, R. M., Faluvegi, G., Fiore, A. M., Hess, P., Koch, D. M., MacKenzie, I. A., Sanderson, M. G., Schultz, M. G., Schulz, M., Stevenson, D. S., Teich, H., Textor, C., Wild, O., Bergmann, D. J., Bey, I., Bian, H., Cuvelier, C., Duncan, B. N., Folberth, G., Horowitz, L. W., Jonson, J., Kaminski, J. W., Marmer, E., Park, R., Pringle, K. J., Schroeder, S., Szopa, S., Takemura, T., Zeng, G., Keating, T. J., and Zuber, A.: A multi-model assessment of pollution transport to the Arctic, Atmos. Chem. Phys., 8, 5353–5372, http://dx.doi.org/10.5194/acp-8-5353-2008doi:10.5194/acp-8-5353-2008, 2008.

Sillman, S., Logan, J. A., and Wofsy, S. C.: The sensitivity of ozone to nitrogen oxides and hydrocarbons in regional ozone episodes, J. Geophys. Res., 95, 1837–1852, 1990.

Slusher, D. L., Huey, L. G., Tanner, D. J., Flocke, F. M., and Roberts, J. M.: A thermal dissociation-chemical ionization mass spectrometry (TD-CIMS) technique for the simultaneous measurement of peroxyacyl nitrates and dinitrogen pentoxide, J. Geophys. Res., 109, D19315, http://dx.doi.org/10.1029/2004JD004670doi:10.1029/2004JD004670, 2004.

Stroud, C., Madronich, S., Atlas, E., Ridley, B., Flocke, F., Weinheimer, A., Talbot, R., Fried, A, Wert, B., Shetter, R., Lefer, B., Coffey, M, Heikes, B., and Blake, D.: Photochemistry in the arctic free troposphere: NOx budget and the role of odd nitrogen reservoir recycling, Atmos. Environ., 37, 3351–3364, 2003.

Tang, Y., Carmichael, G. R., Woo. J.-H., Thongboonchoo, N., Kurata, G., Uno, I., Streets, D. G., Blake, D. R., Weber, R. J., Talbot, R. W, Kondo, Y., Singh, H. B., and Wang, T.: Influences of biomass burning during the Transport and Chemical Evolution Over the Pacific (TRACE-P) experiment identified by the regional chemical transport model, J. Geophys. Res., 108, 8824, http://dx.doi.org/10.1029/2002JD003110doi:10.1029/2002JD003110, 2003.

Thompson, A. M. M., Sparling, L. C., Kondo, Y., Anderson, B. E., Gregory, G. L., and Sachse, G. W.: Perspectives on NO, NOy, and fine aerosol sources and variability during SONEX, Geophys. Res. Lett., 26, 3073–3076, 1999.

Weinheimer, A. J., Walega, J. G., Ridley, B. A., Gary, B. L., Blake, D. R., Blake, N. J., Rowland, F. S., Sachse, G. W., Anderson, B. E., and Collins, J. E.: Meridional distributions of NOx, NOy, and other species in the lower stratosphere and upper troposphere during AASE II, Geophys. Res. Lett., 21, 2583–2586, 1994.

Wisthaler, A., Hansel, A., Dickerson, R. R., and Crutzen, P. J.: Organic trace gas measurements by PTR-MS during INDOEX 1999, J. Geophys. Res., 107, 8024, http://dx.doi.org/10.1029/2001JD000576doi:10.1029/2001JD000576, 2002.

Wennberg, P. O., Hanisco, T. F., Jaeglé, L., Jacob, D. J., Hintsa, E. J., Lanzendorf, E. J., Anderson, J. G., Gao, R.-S., Keim, E. R., Donnelly, S. G., Del Negro, L. A., Fahey, D. W., KcKeen, S. A., Salawitch, R. J., Webster, C. R., May, R. D., Herman, R. L., Proffitt, M. H., Margitan, J. J., Atlas, E. L., Schauffler, S. M., Flocke, F., McElroy, C. T., and Bui, T. P.: Hydrogen Radicals, Nitrogen Radicals, and the Production of O3 in the Upper Troposphere, Science, 279, 49–53, 1998.

Wofsy, S. C., Sachse, G. W., Gregory, G. L., Blake, D. R., Bradshaw, J. D., Sandholm, S. T., Singh, H. B., Barrick, J. A., Harriss, R. C., Talbot, R. W., Shipham, M. A., Browell, E. V., Jacob, D. J., and Logan, J. A.: Atmospheric chemistry in the Arctic and sub-Arctic: Influence of natural fires, industrial emissions, and stratospheric inputs, J. Geophys. Res., 97, 16731–16746, 1992.