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A SPARC Success Story: The Role of Halogen Chemistry in Polar Stratospheric Ozone Depletion

A SPARC Success Story: The Role of Halogen Chemistry in Polar Stratospheric Ozone Depletion An Update on the Initiative Sponsored by the Stratospheric Processes and their Role in Climate (SPARC) Project of the World Climate Research Programme Initiative Co-Chairs:

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A SPARC Success Story: The Role of Halogen Chemistry in Polar Stratospheric Ozone Depletion

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  1. A SPARC Success Story: The Role of Halogen Chemistry in Polar Stratospheric Ozone Depletion An Update on the Initiative Sponsored by the Stratospheric Processes and their Role in Climate (SPARC) Project of the World Climate Research Programme Initiative Co-Chairs: Michael J. Kurylo (UMBC/GEST) Björn-Martin Sinnhuber (U. Bremen) WCRP SPARC Scientific Steering Group 17th Session Kyoto, Japan 26-30 October 2009

  2. ClOOCl Spectral and Absorption Cross-Section Data Available for the JPL 06-2 Evaluation

  3. A Greater Problem Arises

  4. Models Using Pope et al. Cross Sections Yield Less O3 Loss than Observed: Antarctic simulation using CLAMS model Pope 2007 JPL 2006 Huder & DeMore 1994 JPL 2006 Observed Ozone Burkholder 1990 von Hobe et al., ACP, 2007

  5. Modeled Ozone Lossfor: GREEN DASHED: Pope et al. (2007), BrO from CH3Br & Halons GREEN SOLID : Pope et al. (2007), measured BrO Calculated Ozone Loss for Model Constrained by SOLVE Measurements of ClO+2×ClOOCl JPL 2006 Modeled Ozone Loss for: BLACK : JPL 02 Kinetics, BrO from CH3Br & Halons BLUE DOTTED : JPL 02 Kinetics, BrOx from measured BrO BLUE DASHED: JPL 02 Kinetics except Burkholder et al. (1990) cross section BLUE SOLID : Burkholder et al. (1990) cross section and measured BrO Observed Ozone Loss, Match Models Using Pope et al. Cross Sections Yield Less O3 Loss than Observed: Arctic simulation using box model constrained by observed ClOx Figure 4-17, WMO 2007, adapted from Frieler et al., GRL, 2006 Updated to include Pope et al. cross section by R. Schofield, M. Rex, T. Canty and R. Salawitch

  6. Pope et al. cross sections in MOZART3/WACCM1b yield half as much ozone loss as Burkholder et al. cross sections 0 pptv Bry 22 pptv Bry Kinnison, Brasseur, Orlando, Garcia, Tilmes

  7. Burkholder et al., 1990 JPL 2006 Huder and DeMore, 1995 Pope et al., 2007 The UV/Vis Absorption Spectrum of Matrix-Isolated Dichlorine Peroxide, ClOOCl M. von Hobe, F. Stroh, H. Beckers, T. Benter, and H. Willner Phys. Chem. Chem. Phys., 2009, 11, 1571 - 1580, DOI: 10.1039/b814373k ClOOCl Cross Section (cm2) von Hobe et al., 2008

  8. More Recent Published Gas Phase Spectra Chen et al., UV Absorption Cross Sections of ClOOCl are Consistent with Ozone Degradation Models, Science, 324, 781, 8 May 2009.

  9. NASA / JPL Data Panel Interim Recommendation - 2009 "Chemical Kinetics and Photochemical Data for Use in Atmospheric Studies” Evaluation Number 16 of the NASA Panel for Data Evaluation", JPL Publication 09-XX (2009). S. P. Sander, R. R. Friedl, D. M. Golden, M. J. Kurylo, P. H. Wine, J. Abbatt, J. B. Burkholder, C. E. Kolb, G. K. Moortgat, R. E. Huie, and V. L. Orkin Soon to be available at http://jpldataeval.jpl.nasa.gov/.

  10. NASA / JPL 09: Estimated Error Limits Revised

  11. “Chlorine-Catalyzed Ozone Destruction: Cl Atom Production from ClOOCl Photolysis” D. M. Wilmouth, T. F. Hanisco, R. M. Stimpfle, and J. G. Anderson J. Phys. Chem. (in press) Available for download on the J. Phys Chem A ASAP website:http://pubs.acs.org/doi/pdf/10.1021/jp9053204

  12. “Chlorine-Catalyzed Ozone Destruction: Cl Atom Production from ClOOCl Photolysis” Wilmouth et al., J. Phys. Chem. (in press)

  13. “Chlorine-Catalyzed Ozone Destruction: Cl Atom Production from ClOOCl Photolysis” Wilmouth et al., J. Phys. Chem. (in press)

  14. “UV Absorption Spectrum of the ClO Dimer (Cl2O2) between 200 and 420 nm” D. K. Papanastasiou, V. C. Papadimitriou, D. W. Fahey, and J. B. Burkholder J. Phys. Chem. (in press)

  15. “UV Absorption Spectrum of the ClO Dimer (Cl2O2) between 200 and 420 nm” D. K. Papanastasiou, V. C. Papadimitriou, D. W. Fahey, and J. B. Burkholder J. Phys. Chem. (in press) Comparison of wavelength dependent Cl2O2 atmospheric photolysis rate coefficients, J(λ), calculated for a solar zenith angle (SZA) of 86at an altitude of 20 km

  16. “UV Absorption Spectrum of the ClO Dimer (Cl2O2) between 200 and 420 nm” D. K. Papanastasiou, V. C. Papadimitriou, D. W. Fahey, and J. B. Burkholder J. Phys. Chem. (in press) Upper Frame: Integrated atmospheric photolysis rate coefficients, J, calculated for Cl2O2 as a function of solar zenith angle (SZA). Lower Frame: Same data relative to the values obtained using the NASA/JPL recommended Cl2O2 cross section data.

  17. JPL 09 Recommendation & Most Recent Lab Studies

  18. Conclusions The ClOOCl cross section has been perhaps the largest source of uncertainty in our description of polar ozone loss. The laboratory measurement of the ClOOCl cross section by Pope et al. (2007) fell outside the range of uncertainty defined by prior laboratory studies, leading to much discussion, deliberation, and debate within the atmospheric chemistry community. The community met in Cambridge, England (June 2008) to examine our understanding of polar ozone loss (laboratory, theory, field observations, and modelling) in light of the Pope et al. study.A detailed report from that workshop is available electronically at: http://www.atmosp.physics.utoronto.ca/SPARC/index.html Several subsequent laboratory studies (published or about to be published) have failed to reproduce the Pope et al. ClOOCl cross sections and provide strong support for our understanding of chlorine-catalyzed ozone loss in the polar stratosphere. The SPARC Initiative played an important role in fostering this new work!

  19. JPL-09 Recommendations on theClO + ClO  ClOOClEquilibrium Constant "Chemical Kinetics and Photochemical Data for Use in Atmospheric Studies” Evaluation Number 16 of the NASA Panel for Data Evaluation", JPL Publication 09-XX (2009). S. P. Sander, R. R. Friedl, D. M. Golden, M. J. Kurylo, P. H. Wine, J. Abbatt, J. B. Burkholder, C. E. Kolb, G. K. Moortgat, R. E. Huie, and V. L. Orkin Soon to be available at http://jpldataeval.jpl.nasa.gov/.

  20. Lab Data Used in the JPL 2009 Recommendation for KEQ Over the Temperature Range 180<T/K<300

  21. Lab Data Together with Various Fits for KEQ Over the Temperature Range 180<T/K<300

  22. JPL 2006 and JPL 2009 Recommendations for KEQ Together with Various Fits from 180 < T/K < 225

  23. Salawitch / Canty Analysis of Field Data Filtered for SZA > 105 Displayed on the Previous Plot

  24. “Constraining the ClO/ClOOCl Equilibrium Constant from Aura Microwave Limb Sounder Measurements of Nighttime ClO” M. Santee, S. Sander, N. Livesey and L. Froidevaux (to be submitted to PNAS Special Issue on Atmospheric Chemistry) Preliminary

  25. Acknowledgements • NASA/JPL Panel for Data Evaluation • esp. D. Golden & J. Burkholder • New Lab Studies • D. Wilmouth & J. Anderson (Harvard U.) • J. Burkholder (NOAA-ESRL)

  26. Interface betweenLaboratory Kinetics and the2010 WMO/UNEP Ozone Assessment Lifetimes for Long-Lived Compounds and VSLS’s for Chapters 1 and 5 Based on the most current JPL 2010 and IUPAC Evaluations "Chemical Kinetics and Photochemical Data for Use in Atmospheric Studies” Evaluation Number 17 of the NASA Panel for Data Evaluation JPL Publication 10-XX (2010). S. P. Sander, R. R. Friedl, D. M. Golden, M. J. Kurylo, P. H. Wine, J. Abbatt, J. B. Burkholder, C. E. Kolb, G. K. Moortgat, R. E. Huie, and V. L. Orkin Available Spring 2010 at http://jpldataeval.jpl.nasa.gov/

  27. Influence of JPL 09-XX Recommendationson Model Simulations of NOy and O3Charles Jackman and Eric FlemingSeptember 29, 2009GSFC Fully Coupled 2-D Model Computationsof Constituent Diurnal Cycles1) Compare with UARS odd nitrogen (NO,NO2,HNO3,ClONO2) 2) Compare with Total Ozone Measurements (1988-2002)3) Total Ozone (1980, 2000, time series)

  28. 1) Compare with UARS odd nitrogen (NO, NO2, HNO3, ClONO2) NO+NO2 at Sunset; HNO3+ClONO2 for 24-hour average Model with JPL-09 higher than with JPL-06 [due to increased N2O + O(1D)  2NO reaction]

  29. 2) Compare with Total Ozone Measurements (1988-2002) Total Ozone 1988-2002 average Model with JPL-09 lower than with JPL-06 Largest impact in polar spring, especially SH [~One-half of change due to increased N2O + O(1D)  2NO reaction] -10 DU -15 DU

  30. 3) Total Ozone (1980, 2000, time series) Model with JPL-09 has less ozone than with JPL-06 (higher Cl sensitivity in polar regions with JPL-09) Ozone recovery delayed by ~1 year

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