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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: - PowerPoint PPT Presentation
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A SPARC Success Story:
The Role of Halogen Chemistry inPolar Stratospheric Ozone Depletion
An Update on the Initiative Sponsored by theStratospheric 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 Group17th SessionKyoto, Japan
26-30 October 2009
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Wavelength (nm)
Cox and Hayman (1988) Burkholder et al. (1990) DeMore and Tschuikow (1990) Vogt and Schindler (1990) Molina et al. (1990) Huder and DeMore (1995) Bloss et al. (2001) McKeachie et al. (2004) JPL 2006
ClOOCl Spectral and Absorption Cross-Section Data Available for the JPL 06-2 Evaluation
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Wavelength (nm)
Cox and Hayman (1988) Burkholder et al. (1990) DeMore and Tschuikow (1990) Vogt and Schindler (1990) Molina et al. (1990) Huder and DeMore (1995) Bloss et al. (2001) McKeachie et al. (2004) JPL 2006 Pope et al. (2007)
A Greater Problem Arises
Models Using Pope et al. Cross SectionsYield Less O3 Loss than Observed:
Antarctic simulation using CLAMS model
JPL 2006
Burkholder 1990
Pope 2007
Huder & DeMore 1994
von Hobe et al., ACP, 2007
ObservedOzone
JPL 2006
Figure 4-17, WMO 2007, adapted from Frieler et al., GRL, 2006Updated to include Pope et al. cross section by R. Schofield, M. Rex, T. Canty and R. Salawitch
JPL 2006
Observed OzoneLoss, Match
Calculated Ozone Loss for ModelConstrained by SOLVE Measurements
of ClO+2×ClOOCl
Modeled Ozone Loss for: GREEN DASHED: Pope et al. (2007), BrO from CH3Br & Halons GREEN SOLID : Pope et al. (2007), measured BrO
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
Models Using Pope et al. Cross SectionsYield Less O3 Loss than Observed:
Arctic simulation using box modelconstrained by observed ClOx
0 pptv Bry
22 pptv Bry
Kinnison, Brasseur, Orlando, Garcia, Tilmes
Pope et al. cross sections in MOZART3/WACCM1b yield half as much ozone loss as Burkholder et al. cross sections
Huder and DeMore, 1995
JPL 2006
Burkholder et al., 1990
Pope et al., 2007
ClO
OC
l Cro
ss S
ect
ion
(cm
2)
von Hobe et al., 2008
The UV/Vis Absorption Spectrum of Matrix-IsolatedDichlorine 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
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.
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/.
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Wavelength (nm)
NASA / JPL 09: Estimated Error Limits Revised
“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
“Chlorine-Catalyzed Ozone Destruction:Cl Atom Production from ClOOCl Photolysis”
Wilmouth et al., J. Phys. Chem. (in press)
“Chlorine-Catalyzed Ozone Destruction:Cl Atom Production from ClOOCl Photolysis”
Wilmouth et al., J. Phys. Chem. (in press)
“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)
“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
“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.
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2.5
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0.5
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( )Wavelength nm
09JPL 09 . JPL Est Error IUPAC (2007) .Pope et al (2007) .von Hobe et al (2009) .Chen et al (2009) .Wilmouth et al (2009) .Papanastasiou et al(2009)
JPL 09 Recommendation & Most Recent Lab Studies
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!
JPL-09 Recommendations on theClO + ClO ClOOClEquilibrium Constant
"Chemical Kinetics and Photochemical Datafor 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/.
Lab Data Used in the JPL 2009 Recommendation for KEQ Over the Temperature Range 180<T/K<300
Lab Data Together with Various Fits for KEQ
Over the Temperature Range 180<T/K<300
JPL 2006 and JPL 2009 Recommendations for KEQ
Together with Various Fits from 180 < T/K < 225
Salawitch / Canty Analysis of Field DataFiltered for SZA > 105 Displayed on the Previous Plot
“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)
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)
Interface betweenLaboratory Kinetics and the
2010 WMO/UNEP Ozone Assessment
Lifetimes for Long-Lived Compounds and VSLS’s for Chapters 1 and 5
Based on the most currentJPL 2010 and IUPAC Evaluations
"Chemical Kinetics and Photochemical Datafor Use in Atmospheric Studies”
Evaluation Number 17 of the NASA Panel for Data EvaluationJPL 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/
Influence of JPL 09-XX Recommendationson Model Simulations of NOy and O3
Charles Jackman and Eric FlemingSeptember 29, 2009
GSFC Fully Coupled 2-D Model Computationsof Constituent Diurnal Cycles
1) Compare with UARS odd nitrogen (NO,NO2,HNO3,ClONO2) 2) Compare with Total Ozone Measurements (1988-2002)
3) Total Ozone (1980, 2000, time series)
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]
2) Compare with Total Ozone Measurements (1988-2002)Total Ozone 1988-2002 average
Model with JPL-09 lower than with JPL-06Largest impact in polar spring, especially SH
[~One-half of change due to increased N2O + O(1D) 2NO reaction]
-15 DU
-10 DU
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