Paul O. Wennberg

R. Stanton Avery Professor of Atmospheric Chemistry and Environmental Science and Engineering; Executive Officer for Environmental Science and Engineering; Acting Director, Ronald and Maxine Linde Center for Global Environmental Science
B.A., Oberlin College, 1985; Ph.D., Harvard University, 1994. Associate Professor of Atmospheric Chemistry and Environmental Engineering Science, Caltech, 1998-2001; Professor, 2001-03; Professor of Atmospheric Chemistry and Environmental Science and Engineering, 2003-04; Avery Professor, 2004-; Director, Linde Center, 2008-11; Executive Officer, 2012-; Acting Director, Linde Center, 2012-.
My research group applies traditional physical chemistry techniques (e.g. LIF, absorption spectroscopy, mass spectroscopy) to study the mechanisms of chemical transformation in the Earth's atmosphere. Through these studies, we wish to understand the oxidative chemistry of the atmosphere and how this chemistry is influenced by and in turn influences the biosphere. An important component of this research effort is to understand the influence of anthropogenic activity on the global atmosphere.

In the laboratory, we are studying the interactions of ultraviolet, visible, and infrared radiation with a number of important atmospheric trace gases. The aim of this work is to better elucidate the coupling of radiation and chemistry in the upper troposphere and lower stratosphere. The photodissociation of a number of gases (e.g. nitric and peroxynitric acids, and HOONO) in this region of the atmosphere occurs in the spectral region between 310 and 400 nm. In general, the rate of photodissociation is poorly known because the cross sections and photo-physics are not well characterized at these wavelengths. In our laboratory, we have coupled a tunable OPO laser system with a highly sensitive laser induced fluorescence detection system to accurately measure the product of the quantum yield and the absorption cross section for a number of species. We are using model calculations of the transmission of sunlight through the atmosphere to interpret these measurements within the context of the atmospheric photochemistry.

We have also developed a new class of instrumentation for airborne measurement of a number of acids and bases that contribute to the formation of atmospheric aerosol. In a collaborative effort with Caltech Prof. Richard Flagan and Dr. Fred Eisele's (National Center for Atmospheric Research), we have built a selected ion chemical ionization mass spectrometer for use on the NASA ER-2 and the DC8. The aim of these studies is to characterize the composition of both the gas and aerosol phases. We measure in situ the concentrations of a number of acids and bases (such as nitric acid, sulfuric acid, and ammonia). In this way, we are working to understand both the mechanism for the production of aerosol and the influence of heterogeneous chemistry occurring in and on these particles. This instrument first participated in the NASA SOLVE campaign, January - March, 2000, Kiruna, Sweden.

More recently, my students Rebecca Washenfelder and Zhonghua Yang, together with JPL scientists Geoff Toon and Jean-Francois Blavier, have begun development of a high resolution spectrograph for measurement of the column burden of CO2. These observations provide a new constraint on the global carbon cycle and, in addition, are aimed to help validate future space-based observations of the same quantity.

 

Other Links of Interest

Ozone:

Kinetics and spectroscopy atmospheric research groups:

Other Atmospheric Chemistry Links:

Other atmospheric chemistry field investigators I work with:

Selected Publications 

1. Kwan, A.J., J.D. Crounse, A.D. Clarke, Y. Shinozuka, B.E. Anderson, J.H. Crawford, M.A. Avery, C.S. McNaughton, W.H. Brune, H.B. Singh, and P.O. Wennberg, "On the flux of oxygenated volatile organic compounds from organic aerosol oxidation", Geophys. Res. Lett., in press, 2006.

2. Counse, J.D., K.A. McKinney, A.J. Kwan, and P.O. Wennberg, "Measurement of gas-phase hydroperoxides by chemical ionization mass spectrometry (CIMS)", Anal. Chem., in press, 2006

3. Washenfelder, R. A., G. C. Toon, J-F. Blavier, Z. Yang, N. T. Allen, P. O Wennberg, S. A. Vay, D. M. Matross, "Carbon dioxide column abundances at the Wisconsin tall tower site", J. Geophy. Res., in press, 2006

4. Bosch, H., G.C. Toon, B. Sen, R.A. Washenfelder, P.O. Wennberg, M. Bushwitz, R. De Beek, J.P. Burrows, D. Crisp, M. Christi, B.J. Connor, V. Natraj, and Y.L. Yung,"Space-based near-IR CO2 Measurements: Testing the OCO Retrieval Algorithm and Validation Concept Using SCIAMACHY Observations over Park Falls, Wisconsin, J. Geophys. Res., in press, 2006.

5. Kleinbohl A, Toon GC, Sen B, Blavier JFL, Weisenstein DK, Strekowski RS, Nicovich JM, Wine PH, Wennberg PO, "On the stratospheric chemistry of hydrogen cyanide", Geophys. Res. Lett., 33, Art. No. L11806, 2006

6. Fry J.L., Matthews J, Lane JR, Roehl CM, Sinha A, Kjaergaard HG, Wennberg PO, "OH-stretch vibrational spectroscopy of hydroxymethyl hydroperoxide", J. Phys. Chem. A 110, 7072-7079, 2006

7. Kleinbohl A, Toon GC, Sen B, Blavier J-F, Weisenstein, D., Wennberg P.O., "Infrared measurements of atmospheric CH3CN", Geophys. Res. Lett., 32, Art. No. L23807, 2005

8. S.A. Nizkorodov, J.D. Crounse, J.L. Fry, C.M. Roehl, P.O. Wennberg, Near-IR photodissociation of peroxy acetyl nitrate, Atmos. Chem. Phys., 5, 385-392, 2005

9. R.J. Salawitch, D.K. Weisenstein, L.J. Kovalenko, C.E. Sioris, P.O. Wennberg, K. Chance, M.K.W. Ko, C.A. McLinden, Sensitivity of ozone to bromine in the lower stratosphere, Geophys. Res. Lett., 32, Art. No. L05811, 2005

10. Z. Yang, P.O. Wennberg, R.P. Cageao, T.J. Pongetti, G.C. Toon and S.P. Sander, Ground-based photon path measurements from solar absorption spectra of the O2 A-band, J. Quant. Spect. Rad. Trans., 90, 309, 2005.

11. S. Dhaniyala, P.O. Wennberg, R.C. Flagan, D.W. Fahey, M.J. Northway, R.S. Gao, T.P. Bui, Stratospheric aerosol sampling: Effect of a blunt-body housing on inlet sampling characteristics, Aerosol Sci. Tech., 38, 1080, 2004.

12. D. Crisp, Atlas RM, Breon FM, Brown LR, Burrows JP, Ciais P, Connor BJ, Doney SC, Fung IY, Jacob DJ, Miller CE, O'Brien D, Pawson S, Randerson JT, Rayner P, Salawitch RJ, Sander SP, Sen B, Stephens GL, Tans PP, Toon GC, Wennberg PO, Wofsy SC, Yung YL, Kuang Z, Chudasama B, Sprague G, Weiss B, Pollock R, Kenyon D, Schroll S, The orbiting carbon observatory (OCO) mission, Adv. Space Res., 34, 700, Sp.Iss. 2004.

13. P.O. Wennberg, S. Peacock, J.T. Randerson, R. Bleck, Recent changes in the air-sea gas exchange of methyl chloroform, Geophys. Res. Lett., 31, L16112, doi:10.1029/2004GL020476, 2004.

14. J.L. Fry, S.A. Nizkorodov, M. Okumura, C.M. Roehl, J.S. Francisco, P.O. Wennberg, Cis-cis and trans-perp HOONO: Action spectroscopy and isomerization kinetics, J. Chem. Phys., 121, 1432-1448, 2004.

15. K.A. McKinney, P.O. Wennberg, S. Dhaniyala, D.W. Fahey, M.J. Northway, K.F. Kunzi, A. Kleinbohl, M. Sinnhuber, H. Kullmann, H. Bremer, M.J. Mahoney, T.P. Bui, Trajectory studies of large HNO3-containing PSC particles in the Arctic: Evidence for the role of NAT, Geophys. Res. Lett., 31, L05110, 2004.

16. S.A. Nizkorodov, J. Crounse, J. Fry, C.A. Roehl, and P.O. Wennberg, Near-IR photodissociation of peroxy acetyl nitrate, Atm. Chem. Phys. Dis., 4, 1269-1289, 2004.

17. T. Rahn, J.M. Eiler, K.A. Boering, P.O. Wennberg, M.C. McCarthy, S. Tyler, S. Schauffler, S. Donnelly, and E. Atlas, "Extreme deuterium enrichment in stratospheric hydrogen and its significance for the global atmospheric budget of H2" Nature, 424, 918-921, 2003.

18. R.A. Washenfelder, G.C. Toon, and P.O. Wennberg, "Tropospheric methane retrieved from ground-based near-IR solar spectra", Geophys. Res. Lett., 30, 2226, 2003.

19. R.A. Washenfelder, C.M. Roehl, K.A. McKinney, R.R. Julian, and P.O. Wennberg, "A compact, lightweight gas standards generator for permeation tubes, Rev. Sci. Instru., 74, 3151, 2003.

20. Z.M. Kuang, G.C. Toon, P.O. Wennberg, and Y.L. Yung, "Measured HDO/H2O ratios across the tropical tropopause", Geophy. Res. Lett., 30, 1372, 2003.

21. S. Dhaniyala, R.C. Flagan, K.A. McKinney, P.O. Wennberg, "Novel aerosol/gas inlet for aircraft based measurements", Aerosol Sci. Tech., 37, 828-840, 2003.

22. M. Rex et al., Chemical depletion of Arctic ozone in winter 1999/200, J. Geophys. Res., 107, Art. No. 8276, 2002.

23. M.Y. Danilin, M.K.W. Ko, R.M. Bevilacqua, L.V. Lyjak, L. Froedevaux, M.L. Santee, J.M. Zawodny, K.W. Hoppel, E.C. Richard, J.R. Spackman, E.M. Weinstock, R.L. Herman, K.A. McKinney, P.O. Wennberg, F.L. Eisele, R.M. Stimplfle, C.J. Scott, J.W. Elkins, T.V. Bui, "Comparison of ER-2 aircraft and POAM III, MLS, and SAGE II satellite measurements during SOLVE using traditional correlative analysis an d trajectory hunting technique, J. Geophys. Res., 108, 8315, 2002.

24. M.J. Northway, R.S. Gao, P.J. Popp, J.C. Holecek, D.W. Fahey, K.S. Carslaw, M.A. Tolbert, L.R. Lait, S. Dhaniyala, R.C. Flagan, P.O. Wennberg, M.J. Mahoney, R.L. Herman, G.C. Toon, and T.P. Bui, "An analysis of large HNO3-containing particles sampled in the Arctic stratosphere during the winter of 1999/2000", J. Geophys. Res., 108, 8298, 2002.

25. R.J. Salawitch, P.O. Wennberg, G.C. Toon, B. Sen, and J.F. Blavier, "Near-IR Photolysis of HO2NO2: Implications for HOx", Geophys. Res. Lett, 29, 1762, 2002.

26. Y. Zhonghua, G.C. Toon, J.S. Margolis, and P.O. Wennberg, "Atmospheric CO2 retrieved from ground-based near IR solar spectra", Geophys. Res. Lett., 29, 1339, 2002.

27. S. A. Nizkorodov and P.O. Wennberg, "First spectroscopic observation of gas-phase HOONO", J. Phys. Chem. A, 106, 855, 2002.

28. S. Dhaniyala, K.A. McKinney, and P.O. Wennberg, "Lee-wave clouds and denitrification of the polar stratosphere", Geophys. Res. Lett., 29, 1332, 2002.

29. C.M. Roehl, S.A. Nizkorodov, H. Zhang, G.A. Blake, and P.O. Wennberg, "Photodissociation of peroxynitric acid in the near IR", J. Phys. Chem. A, 106, 3766, 2002.

30. D.W. Fahey, R.S. Gao, K.S. Carslaw, J. Kettleborough, P.J. Popp, M.J. Northway, J.C. Holecek, S.C. Ciciora, R.J. McLaughlin, T.L. Thompson, R.H. Winkler, D.G. Baumgardner, B. Gandrud, P.O. Wennberg, S. Dhaniyala, K. McKinney, T. Peter, R.J. Salawitch, T.P. Bui, J.W. Elkins, C.R. Webster, E.L. Atlas, H. Jost, J.C. Wilson, R.L. Herman, A. Kleinbohl, M. von Konig, "The detection of large HNO3-containing particles in the winter arctic stratosphere", Science, 291, 1026-1031, 2001.

31. L. Jaegle, D.J. Jacob, W.H. Brune, and P.O. Wennberg, "Chemistry of HOx radicals in the upper troposphere", Atmos. Environ., 35, 469, 2001.

32. E.J. Lanzendorf, T.F. Hanisco, R.M. Stimpfle, J.G. Anderson, P.O. Wennberg, R.C. Cohen, R.S. Gao, J.J. Margitan, and T.P. Bui, "Establishing the dependence of [HO2]/[OH] on temperature, halogen, loading, O3, and NOx based on in situ measurements from the NASA ER-2", J. Phys. Chem., 105, 1535, 2001.

33. E.J. Lanzendorf, T.F. Hanisco, R.M. Stimpfle, J.G. Anderson, P.O. Wennberg, and R.C. Cohen, "Comparing Atmospheric [HO2]/[OH] to modeled [HO2]/[OH]: identifying discrepancies in reaction rate constants", Geophys. Res. Lett., 28, 967, 2001.

34. T.F. Hanisco, E.J. Lanzendorf, P.O. Wennberg, K.K. Perkins, R.M. Stimpfle, P.B. Voss, J.G. Anderson, R.C. Cohen, D.W. Fahey, R.S. Gao, E.J. Hintsa, R.J. Salawitch, J.J. Margitan, C.T. McElroy, and C. Midwinter, "Sources, Sinks and the distribution of OH in the lower stratosphere", J. Phys. Chem., 105,1543, 2001.

35. K.K. Perkins, T.F. Hanisco, R.C. Cohen, L.C. Koch, R.M. Stimpfle, P.B. Voss, G.P. Bonne, E.J. Lanzendorf, J.G. Anderson, P.O. Wennberg, R.S. Gao, L.A. Del Negro, R.J. Salawitch, C.T. McElroy, E.J. Hintsa, M. Lowenstein, and T.P. Bui, "The NOx-HNO3 system in the lower stratosphere: Insights from in situ measurements and implications of the JHNO3 - OH relationship", J. Phys. Chem 105, 1521-1534, 2001.

36. D.W. Fahey, R.S. Gao, K.S. Carslaw, J. Kettleborough, P.J. Popp, M.J. Northway, J.C. Holecek, S.C. Ciciora, R.J. McLaughlin, T.L. Thompson, R.H. Winkler, D.G. Baumgardner, B. Gandrud, P.O. Wennberg, S. Dhaniyala, K. McKinney, T. Peter, R.J. Salawitch, T.P. Bui, J.W. Elkins, C.R. Webster, E.L. Atlas, H. Jost, J.C. Wilson, R.L. Herman, A. Kleinbohl, M. von Konig, "The detection of large HNO3-containing particles in the winter arctic stratosphere", Science, 291, 1026-1031, 2001

37. P.B. Voss, R.M. Stimpfle, R.C. Cohen, T.F. Hanisco, G.P. Bonne, K.K. Perkins, E.J. Lanzendorf, J.G. Anderson, R.J. Salawitch, C.R. Webster, D.C.Scott, R.D. May, P.O. Wennberg, P.A. Newman, L.R. Lait, J.W. Elkins, T.P. Bui, "Inorganic chlorine partitioning in the summer lower stratosphere: Modeled and measured [ClONO2]/[HCl] during POLARIS", J. Geophys. Res., 106, 1713-1732, 2001,

38. R.C. Cohen, K.K. Perkins, L.C. Koch, R.M. Stimpfle, P.O. Wennberg, T.F. Hanisco, E.J. Lanzendorf, G.P. Bonne, P.B. Voss, R.J. Salawitch, L.A. Del Negro, J.C. Wilson, C.T. McElroy, T.P. Bui, "Quantitative constraints on the atmospheric chemistry of nitrogen oxides: An analysis along chemical coordinates", J. Geophys. Res., 105, 24283-24304, 2000.

39. H. Zhang, C.A Roehl, S.P. Sander, P.O. Wennberg, "Intensity of the second and third OH overtones of H2O2, HNO3, and HNO4", J. Geophys. Res., 105, 14593-14, 2000.

40. H. Zhang, P.O. Wennberg,, V. Wu, , G.A. Blake, "Fractionation of 14N15N16O and 15N14N16O during photolysis at 213 nm", Geophys. Res. Lett., 27, 2481-2484, 2000

41. D.W. Fahey, R.S.Gao, L.A. Del Negro, E.R. Keim, S.R. Kawa, R.J. Salawitch, P.O. Wennberg, T.F. Hanisco, E.J. Lanzendorf, K.K. Perkins, S.A. Lloyd, W.H. Swartz, M.H. Proffitt, J.J. Margitan, J.C. Wilson, R.M. Stimpfle, R.C. Cohen, C.T. McElroy, C.R. Webster, M. Loewenstein, J.W. Elkins, T.P. Bui, "Ozone destruction and production rates between spring and autumn in the Arctic stratosphere", Geophys. Res. Lett., 27, 2605-2608, 2000.

42. Del Negro LA, Fahey DW, Gao RS, Donnelly SG, Keim ER, Neuman JA, Cohen RC, Perkins KK, Koch LC, Salawitch RJ, Lloyd SA, Proffitt MH, Margitan JJ, Stimpfle RM, Bonne GP, Voss PB, Wennberg PO, McElroy CT, Swartz WH, Kusterer TL, Anderson DE, Lait LR, Bui TP "Comparison of modeled and observed values of NO2 and J(NO2) during the Photochemistry of Ozone Loss in the Arctic Region in Summer, (POLARIS) mission", J. Geophys. Res., 104, 26687-26703, 1999.

43. R.L. Herman, C.R. Webster, R.D. May, D.C. Scott, H.Hu, E.J. Moyer, P.O. Wennberg, T.F. Hanisco, E.J. Lanzendorf, R.J. Salawitch, Y.L. Yung, J.J. Margitan, and T.P. Bui, "Measurements of CO in the upper troposphere and lower stratosphere", Chemosphere, 1, 173, 1999.

44. P.O. Wennberg, R.J. Salawitch, D.J. Donaldson, T.F. Hanisco, E.J. Lanzendorf, K.K. Perkins, S.A. Lloyd, V. Vaida, R.S. Gao, E.J. Hintsa, R.C. Cohen, W.H. Swartz, T.L. Kusterer, and D.E. Anderson, "Twilight observations suggest unknown sources of HOx", Geophys. Res. Lett., 26, 1373-1376, 1999.

45. R.S. Gao, D.W. Fahey, L.A. Del Negro, S.G. Donnelly, E.R. Keim, J.A. Neuman, E. Teverovskaia, P.O. Wennberg, T.F. Hanisco, E.J. Lanzendorf, M.H. Proffitt, J.J. Margitan, J.C. Wilson, J.W. Elkins, R.M. Stimpfle, R.C. Cohen, C.T. McElroy, T.P. Bui, R.J. Salawitch, S.S. Brown, A.R. Ravishankara, R.W. Portmann, M.K.W. Ko, D.K. Weisenstein, P.A. Newman, "A comparison of observations and model simulations of NOx/NOy in the lower stratosphere", Geophys. Res. Lett., 26, 1153-1156, 1999.

46. P.O. Wennberg, T.F. Hanisco, L. Jaeglé, D.J. Jacob, E.J. Hintsa, E.J. Lanzendorf, J.G. Anderson, R.S. Gao, E.R. Keim, S.G. Donnelly, L.A. Del Negro, D.W. Fahey, S.A. McKeen, R.J. Salawitch, C.R. Webster, R.D. May, R.L. Herman, M.H. Proffitt, J.J. Margitan, E.L. Atlas, S.M. Schauffler, F. Flocke, C.T. McElroy, T.P. Bui., "Hydrogen Radicals, Nitrogen Radicals, and the production of ozone in the upper troposphere", Science, 279, 49-53, 1998.

47. I. Folkins, P.O. Wennberg, T.F. Hanisco, J.G. Anderson, R.J. Salawitch, "OH, HO2, and NO in two biomass burning plumes: Sources of HOx and implications for ozone production", Geophys. Res. Lett., 24, 3185-3188, 1997.

48. L. Jaeglé, D.J. Jacob, P.O. Wennberg, C.M. Spivakovsky, T.F. Hanisco, E.L. Lanzendorf, E.J. Hintsa, D.W. Fahey, E.R. Keim, M.H. Proffitt, E. Atlas, F. Flocke, S. Schauffler, C.T. McElroy, C. Midwinter, L. Pfister, J.C. Wilson, "Observed OH and HO2 in the upper troposphere suggest a major source from convective injection of peroxides", Geophys. Res. Lett., 24, 3181-3184, 1997.

49. S.A. McKeen, T. Gierczak, J.B. Burkholder, P.O. Wennberg, T.F. Hanisco, E.R. Keim, R.-S. Gao, S.C. Liu, A.R. Ravishankara, and D.W. Fahey, "The photochemistry of acetone in the upper troposphere: A source of odd-hydrogen radicals", Geophys. Res. Lett., 24, 3177-3180, 1997.

50. E.J. Lanzendorf, T.F. Hanisco, N.M. Donahue and P.O. Wennberg, "Comment on: The measurement of tropospheric OH radicals by laser-induced fluorescence spectroscopy during the POPCORN field campaign, by Hofzumahaus et al.", Geophys. Res. Lett., 24, 3037-3038, 1997.

51. L. Jaeglé, C.R. Webster, R.D. May, D.C. Scott, R.M. Stimpfle, D.W. Kohn, P.O. Wennberg, T.F. Hanisco, Cohen, M.H. Proffitt, K.K. Kelly, J. Elkins, D. Baumgardner, J.E. Dye, J.C. Wilson, R.F. Pueschel, K.R. Chan, R.J. Salawitch, A.F. Tuck, S.J. Hovde, Y.L. Yung, , "Evolution and stoichiometry of heterogeneous processing in the Antarctic stratosphere", J. Geophys. Res., 102, 13235-13253, 1997.

52. P.O. Wennberg, J.W. Brault, T.F. Hanisco, R.S. Salawitch, and G.H. Mount, "The atmospheric column abundance of IO: Implications for stratospheric ozone", J. Geophys. Res., 102, 8887-8898 1997 .

53. T.F. Hanisco, P.O. Wennberg, R.C. Cohen, J.G. Anderson, D.W. Fahey, E.R. Keim, R.S. Gao, R.C. Wamsley, S.G. Donnelly, L.A. Del Negro, R.J. Salawitch, K.K. Kelly, and M.H. Proffitt, "The role of HOx in super- and subsonic aircraft exhaust plumes", Geophys. Res. Lett., 24, 65-68, 1997.

54. E.R. Keim, D.W. Fahey, L.A. Del Negro, E.L. Woodbridge, R.S. Gao, P.O. Wennberg, R.C. Cohen, R.M. Stimpfle, K.K. Kelly, E.J. Hintsa, J.C. Wilson, H.H. Jonsson, J.E. Dye, D. Baumgardner, R.S. Kawa, R.J. Salawitch, M.H. Proffitt, M. Lowenstein, J.R. Podolske, and K.R. Chan, "Observations of large reductions in the NO/NOy ratio near the midlatitude tropopause and the role of heterogeneous chemistry", Geophys. Res. Lett., 23, 3223-3226, 1996.

55. M.K. Dubey, T.F. Hanisco, P.O. Wennberg, and J.G. Anderson, "Monitoring potential photochemical interference in the laser-induced fluorescence measurements of atmospheric OH", Geophys. Res. Lett., 23, 3215-3218, 1996.

56. D.W. Fahey, E.R. Keim, K.A. Boering, C.A. Brock, J.C. Wilson, S. Anthony, T.F. Hanisco, P.O. Wennberg, R.C. Miake-Lye, R.J. Salawitch, N. Lousinard, E.L. Woodbridge, R.S. Gao, S.G. Donnelly, R.C. Wamsley, L.A. Del Negro, B.C. Daube, S.C. Wofsy, C.R. Webster, R.D. May, K.K. Kelly, M. Loewenstein, J.R. Podolske, and K.R. Chan, "Emission measurements of the concorde supersonic aircraft In the lower stratosphere", Science, 270, 70, 1995.

57. P.O. Wennberg, T.F. Hanisco, R.C. Cohen, R.M. Stimpfle, L.B. Lapson, and J.G. Anderson, "In Situ measurements of OH and HO2 in the upper troposphere and stratosphere", J. Atmos. Sci., 52, 3413-20, 1995.

58. R.C. Cohen, P.O. Wennberg, R.M. Stimpfle, J. Koplow, J.G. Anderson, D.W. Fahey, E.L. Woodbridge, E.R. Keim, R. Gao, M.H. Proffitt, M. Loewenstein, and K.R. Chan, "Are models of catalytic removal of O3 by HOx accurate? Constraints from In Situ measurements of the OH to HO2 ratio", Geophys. Res. Lett., 21, 2539-2542, 1994.

59. R.J. Salawitch, S.C. Wofsy, P.O. Wennberg, et al., "The distribution of hydrogen, nitrogen, and chlorine Radicals in the lower stratosphere: Implications for changes in O3 due to emission of NOy from supersonic aircraft", Geophys. Res. Lett., 21, 2547-2550, 1994.

60. R.J Salawitch, S.C. Wofsy, P.O. Wennberg, et al., "The diurnal variation of hydrogen, nitrogen, and chlorine radicals: Implications for the heterogeneous production of HNO2", Geophys. Res. Lett., 21, 2551-2554, 1994.

61. R.M. Stimpfle, J.P. Koplow, R.C. Cohen, D.W. Kohn, P.O. Wennberg, D.M. Judah, D.W. Toohey, L.M. Avallone, J.G. Anderson, R.J. Salawitch, E.L. Woodbridge, C.R. Webster, R.D. May, M.H. Proffitt, K. Aiken, J. Margitan, M. Loewenstein, J.R. Podolske, L. Pfister, and K.R. Chan, "The response of ClO radical concentrations to variations in NO2 radical concentrations in the lower stratosphere", Geophys. Res. Lett., 21, 2543-2546, 1994.

62. P.O. Wennberg, R.C. Cohen, R.M. Stimpfle, J.P. Koplow, J.G. Anderson, R.J. Salawitch, D.W. Fahey, E.L. Woodbridge, E.R. Keim, R.S. Gao, C.R. Webster, R.D. May, D.W. Toohey, L.M. Avallone, M.H. Proffitt, M. Loewenstein, J.R. Podolske, K.R. Chan, and S.C. Wofsy, "Removal of stratospheric O3 by radicals: In situ measurements of OH, HO2, NO, NO2, ClO, and BrO", Science, 266, 398-404, 1994.

63. H.A. Michelsen, R.J. Salawitch, P.O. Wennberg, and J.G. Anderson, "Production of O(1D) from photolysis of O3", Geophys. Res. Lett., 21, 2227-2230, 1994.

64. P.O. Wennberg, J.G. Anderson, and D.Weisenstein, "Kinetics of the reactions of ground-state nitrogen atoms (4S 3/2 ) with NO and NO2", J. Geophys. Res., 99, 18839-18846, 1994.

65. P.O. Wennberg, R.C. Cohen, N.L. Hazen, L.B. Lapson, N.T. Allen, T.F. Hanisco, J.F. Oliver, N.W. Lanham, J.N. Demusz, and J.G. Anderson, "An aircraft-borne, laser-induced fluorescence instrument for the in situ detection of hydroxyl and hydroperoxyl radicals", Rev. Sci. Instrum., 65, 1858-1876, 1994.

66. P.O. Wennberg, R.M. Stimpfle, E.M. Weinstock, A.E. Dessler, S.A. Lloyd, L.B. Lapson, J.J. Schwab, and J.G. Anderson, "Simultaneous, in situ measurements of OH, HO2, O3, and H2O: A test of modeled stratospheric HOx chemistry", Geophys. Res. Lett., 17, 1909, 1990.

67. R.M. Stimpfle, P.O. Wennberg, L.B. Lapson, and J.G. Anderson, "Simultaneous, in situ measurements of OH and HO2 in the stratosphere", Geophys. Res. Lett., 17, 1905, 1990.

68. R.M. Stimpfle, L.B. Lapson, P.O. Wennberg, and J.G. Anderson, "Balloon borne in-situ detection of OH in the stratosphere from 37 to 23 km", Geophys. Res. Lett., 16, 1433, 1989.



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  • Extreme deuterium enrichment in stratospheric hydrogen and the global atmospheric budget of H2� Rahn T, Eiler JM, Boering KA, Wennberg, PO et al., Nature, 424, 918-921, 2003.
  • Measured HDO/H2O ratios across the tropical tropopause, Kuang ZM, Toon GC, Wennberg PO, Yung YL, Geophys. Res. Lett., 30, 1372, 2003.
  • A Compact Lightweight gas standards generator for permeation tubes, R.A. Washenfelder, C.M. Roehl, K.A. McKinney, R.R. Julian, and P.O. Wennberg, Rev. Sci. Instrum., 74 (6): 3151-3154, 2003. [pdf]
  • Novel aerosol/gas inlet for aircraft based measurements, S. Dhaniyala, R.C. Flagan, K.A. McKinney, P.O. Wennberg, Aerosol Science and Technology, 37 (10): 828-840, 2003. [pdf]
  • Near-IR Photolysis of HO2NO2: Implications for HOx, R.J. Salawitch, P.O. Wennberg, G.C. Toon, and J.F. Blavier, Geophys. Res. Lett., in press, 2002 [pdf]
  • Atmospheric CO2 retrieved from ground-based near IR solar spectra, Zhonghua Yang, Geoffrey C. Toon, Jack S. Margolis, and Paul O. Wennberg, Geophys. Res. Lett., in press, 2002. [PDF]
  • First spectroscopic observation of gas-phase HOONO, Sergey A. Nizkorodov and Paul O. Wennberg, J. Phys. Chem. A, 106, 855, 2002. [PDF]
  • Lee-wave clouds and denitrification of the polar stratosphere, S. Dhaniyala, K.A. McKinney, and P.O. Wennberg, Geophys. Res. Lett., in press, 2002. [pdf-paper] [pdf-supplementary material]
  • Photodissociation of peroxynitric acid in the near IR, C.M. Roehl, S.A. Nizkorodov, H. Zhang, G.A. Blake, and P.O. Wennberg, J. Phys. Chem. A, in press, 2002. [PDF]
  • The detection of large HNO3-containing particles in the winter arctic stratosphere, D.W. Fahey, R.S. Gao, K.S. Carslaw, J. Kettleborough, P.J. Popp, M.J. Northway, J.C. Holecek, S.C. Ciciora, R.J. McLaughlin, T.L. Thompson, R.H. Winkler, D.G. Baumgardner, B. Gandrud, P.O. Wennberg, S. Dhaniyala, K. McKinney, T. Peter, R.J. Salawitch, T.P. Bui, J.W. Elkins, C.R. Webster, E.L. Atlas, H. Jost, J.C. Wilson, R.L. Herman, A. Kleinbohl, M. von Konig, Science, 291, 1026-1031, 2001. [PDF]
  • Chemistry of HOx radicals in the upper troposphere, L. Jaegle, D.J. Jacob, W.H. Brune, and P.O. Wennberg, Atmos. Environ., 35, 469, 2001.
  • Fractionation of 14N15N16O and 15N14N16O During Photolysis at 213 nm, H. Zhang, P.O. Wennberg, V.H. Wu, G.A. Blake, Geophys. Res. Lett., 27, 2481-2484, 2000.
  • Twilight observations suggest unknown sources of HOx , P.O. Wennberg, R.J. Salawitch, D.J. Donaldson, T.F. Hanisco, E.J. Lanzendorf, K.K. Perkins, S.A. Lloyd, V. Vaida, R.S. Gao, E.J. Hintsa, R.C. Cohen, W.H. Swartz, T.L. Kusterer, D.E. Anderson., Geophys. Res. Lett., 26, 1373-1376, 1999.
  • Hydrogen radicals, nitrogen radicals, and the production of ozone in the upper troposphere, P.O. Wennberg, T.F. Hanisco, L. Jaegl�, D. Jacob, E.J. Hintsa, E.L. Lanzendorf, J.G. Anderson, R.S. Gao, E.R. Keim, S. Donnelly, L. Del Negro, D.W. Fahey, S.A. McKeen, R.J. Salawitch, C.R. Webster, R.D. May, R. Herman, M.H. Proffitt, E. Atlas, S. Schauffler, F. Flocke, T.E. McElroy, P. Bui, Science, 279, 49-53, 1998.
  • Observed OH and HO2 in the upper troposphere suggest a major source from convective injection of peroxides, L. Jaegl�, D.J. Jacob, P.O. Wennberg, C.M. Spivakovsky, T.F. Hanisco, E.L. Lanzendorf, E.J. Hintsa, D.W. Fahey, E.R. Keim, M.H. Proffitt, E. Atlas, F. Flocke, S. Schauffler, C.T. McElroy, C. Midwinter, L. Pfister, J.C. Wilson, , Geophys. Res. Lett., 24, 3181-3184, 1997
  • The atmospheric column abundance of IO: Implications for stratospheric ozone, P.O. Wennberg, J.W. Brault, T.F. Hanisco, R.S. Salawitch, and G.H. Mount, , J. Geophys. Res., 102, 8887-8898 1997.
  • Emission measurements of the concorde supersonic aircraft In the lower stratosphere, D.W. Fahey, E.R. Keim, K.A. Boering, C.A. Brock, J.C. Wilson, S. Anthony, T.F. Hanisco, P.O. Wennberg, R.C. Miake-Lye, R.J. Salawitch, N. Lousinard, E.L. Woodbridge, R.S. Gao, S.G. Donnelly, R.C. Wamsley, L.A. Del Negro, B.C. Daube, S.C. Wofsy, C.R. Webster, R.D.May, K.K. Kelly, M. Loewenstein, J.R. Podolske, and K.R. Chan, Science, 270, 70, 1995.
  • Are models of catalytic removal of O3 by HOx accurate? Constraints from In Situ measurements of the OH to HO2 ratio, R.C. Cohen, P.O. Wennberg, R.M. Stimpfle, J. Koplow, J.G. Anderson, D.W. Fahey, E.L. Woodbridge, E.R. Keim, R. Gao, M.H. Proffitt, M. Loewenstein, and K.R. Chan, Geophys. Res. Lett., 21, 2539-2542, 1994.
  • Removal of stratospheric O3 by radicals: In situ measurements of OH, HO2, NO, NO2, ClO, and BrO, P.O. Wennberg, R.C. Cohen, R.M. Stimpfle, J.P. Koplow, J.G. Anderson, R.J. Salawitch, D.W. Fahey, E.L. Woodbridge, E.R. Keim, R.S. Gao, C.R. Webster, R.D. May, D.W. Toohey, L.M. Avallone, M.H. Proffitt, M. Loewenstein, J.R. Podolske, K.R. Chan, and S.C. Wofsy, , Science, 266, 398-404, 1994.
  • Production of O(1D) from photolysis of O3, H.A. Michelsen, R.J. Salawitch, P.O. Wennberg, and J.G. Anderson, Geophys. Res. Lett., 21, 2227-2230, 1994.
  • "Kinetics of the reactions of ground-state nitrogen atoms (4S 3/2 ) with NO and NO2", P.O. Wennberg, J.G. Anderson, and D.Weisenstein, , J. Geophys. Res., 99, 18839-18846, 1994.
  • "An aircraft-borne, laser-induced fluorescence instrument for the in situ detection of hydroxyl and hydroperoxyl radicals", P.O. Wennberg, R.C. Cohen, N.L. Hazen, L.B. Lapson, N.T. Allen, T.F. Hanisco, J.F. Oliver, N.W. Lanham, J.N. Demusz, and J.G. Anderson, , Rev. Sci. Instrum., 65, 1858-1876, 1994.
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