References

ACP

Atmospheric Chemistry and Physics

ACP

1680-7324

Copernicus GmbH

Göttingen, Germany

10.5194/acp-7-4935-2007

Sensitivity of stratospheric inorganic chlorine to differences in transport

Waugh

D. W.

¹ Strahan

S. E.

² Newman

P. A.

Department of Earth and Planetary Science, Johns Hopkins University, Baltimore, MD, USA

University of Maryland Baltimore County, Goddard Earth Sciences and Technology Center, Baltimore, MD, USA

NASA Goddard Space Flight Center, Greenbelt, MD, USA

26 09 2007

7 18 4935 4941

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Correctly modeling stratospheric inorganic chlorine (Cly) is crucial for modeling the past and future evolution of stratospheric ozone. However, comparisons of the chemistry climate models used in the latest international assessment of stratospheric ozone depletion have shown large differences in the modeled Cly, with these differences explaining many of the differences in the simulated evolution of ozone over the next century. Here in, we examine the role of transport in determining the simulated Cly using three simulations from the same off-line chemical transport model that have the same lower tropospheric boundary conditions and the same chemical solver, but differing resolution and/or meteorological fields. These simulations show that transport plays a key role in determining the Cly distribution, and that Cly depends on both the time scales and pathways of transport. The time air spends in the stratosphere (e.g., the mean age) is an important transport factor determining stratospheric Cly, but the relationship between mean age and Cly is not simple. Lower stratospheric Cly depends on the fraction of air that has been in the upper stratosphere, and transport differences between models having the same mean age can result in differences in the fraction of organic chlorine converted into Cly. Differences in transport pathways result in differences in vertical profiles of CFCs, and comparisons of observed and modeled CFC profiles provide a stringent test of transport pathways in models.

References 1

Bernath, P. F., McElroy, C. T., Abrams, M. C. et al.: Atmospheric Chemistry Experiment (ACE) mission overview, Geophys. Res. Lett., 32, L15S01, doi:10.1029/2005GL022386, 2005.

Bloom, S. C., da Silva, A. M., Dee, D. P., et al.: The Goddard Earth Observation System Data Assimilation System, GEOS DAS Version 4.0.3: Documentation and Validation, NASA TM- 2005-104606 V26, 2005.

Considine, D. E., Connell, P. S., Bergmann, D. J., Rotman, D. A, and Strahan, S. E.: Sensitivity of Global Modeling Initiative model predictions of Antarctic ozone recovery to input meteorological fields, J. Geophys. Res., 109, D15301, doi:10.1029/2003JD004487, 2004.

Douglass, A. R., Stolarski, R. S., Strahan, S. E., and Connell, P.S.: Radicals and reservoirs in the GMI chemistry and transport model: Comparison to measurements, J. Geophys. Res., 109, D16302, doi:10.1029/2003JD004632, 2004. %

Douglass A.R. et % al.: Interhemispheric differences in springtime production of % HCl and ClONO2 in the polar vortices, J. Geophys. Res., 100, % 13967-13978, 1995

Douglass A. R., Stolarski, R. S., Strahan, S. E., and Polansky, B. C.: Sensitivity of Arctic ozone loss to polar stratospheric cloud volume and chlorine and bromine loading in a chemistry and transport model, Geophys. Res. Lett., 33, L17809, doi:10.1029/2006GL026492, 2006.

Eyring, V., Butchart, N., Waugh, D. W., et al.: Assessment of temperature, trace species, and ozone in chemistry-climate model simulations of the recent past, J. Geophys. Res., 111, D22308, doi:10.1029/2006JD007327, 2006.

Eyring, V., Waugh, D. W., Bodeker, G. E., et al.: Multi-model projections of stratospheric ozone in the 21st century, J. Geophys. Res., 112, D16303, doi:10.1029/2006JD008332, 2007.

Hall, T. M.: Path histories and timescales in stratospheric transport: analysis of an idealized model, J. Geophys. Res., 105, 22 811–22 823, 2000.

Newman, P. A., Nash, E. R., Kawa, S. R., Montzka, S. A., and Schauffler, S. M.: When will the Antarctic ozone hole recover?, Geophys. Res. Lett., 33, L12814, doi:10.1029/2005GL025232, 2006.

Newman, P. A., Daniel, J. S., Waugh, D. W., and Nash, E. R.: A new formulation of equivalent effective stratospheric chlorine, Atmos. Chem. Phys., 7, 4537–4552, 2007.

Schauffler, S. M., Atlas, E. L., Donnelly, S. G., et al.: Chlorine budget and partitioning during the Stratospheric Aerosol and Gas Experiment (SAGE) III Ozone Loss and Validation Experiment (SOLVE), J. Geophys. Res.-Atmos., 108(D5), 4173, doi:10.1029/2001JD002040, 2003 %

Santee, M. L., % L. Frodivaux, G. Manney, W. Read, J. Waters, M. Chipperfield, A. % Roche, J. Kummer, J. Mergentaller, and J. Russell III: Chlorine % activation in the lower stratospheric polar region during late % winter: Results from UARS, J. Geophys. Res., 101, 18835-18859, % 1996.

Schoeberl, M. R., Sparling, L., Dessler, A., Jackman, C. H., and Fleming, E. L.: A Lagrangian view of stratospheric trace gas distributions, J. Geophys. Res., 10, 1537–1552, 2000.

Schoeberl, M. R., Douglass, A. R., Zhu, Z., and Pawson, S.: A comparison of the lower stratospheric age spectra derived from a general circulation model and two data assimilation systems, J. Geophys. Res., 108, 4113, doi:10.1029/2002JD002652, 2003.

Schoeberl, M. R., Douglass, A. R., Polansky, B., Boone, C., Walker, K. A., and Bernath, P.: Estimation of stratospheric age spectrum from chemical tracers, J. Geophys. Res., 110, D21303, doi:10.1029/2005JD006125, 2005.

Schubert, S., Rood, R., and Pfaendtner, J.: An assimilated dataset for earth sciences applications, B. Am. Meteorol. Soc., 74, 2331–2342, 1993.

Strahan S. E. and Polansky, B. C.: Meteorological implementation issues in chemistry and transport models, Atmos. Chem. Phys., 6, 2895–2910, 2006.

Waugh, D. W. and Hall, T. M.: Age of stratospheric air: theory, observations, and models, Rev. Geophys., 40, 1010, doi:10.1029/2000RG000101, 2002.

World Meteorological Organization (WMO)/United Nations Environment Programme (UNEP), Scientific Assessment of Ozone Depletion: 2002, World Meteorological Organization, Global Ozone Research and Monitoring Project, Report No. 47, Geneva, Switzerland, 2003.

World Meteorological Organization (WMO)/United Nations Environment Programme (UNEP): Scientific Assessment of Ozone Depletion: 2006, World Meteorological Organization, Global Ozone Research and Monitoring Project, Report No. 50, Geneva, Switzerland, 2007.