ACP Atmospheric Chemistry and Physics ACP 1680-7324 Copernicus GmbH Göttingen, Germany 10.5194/acp-9-9237-2009 Modeling the transport of very short-lived substances into the tropical upper troposphere and lower stratosphere Aschmann J. 1 Sinnhuber B.-M. 1 Atlas E. L. 2 Schauffler S. M. 3 Institute of Environmental Physics, University of Bremen, Bremen, Germany Rosenstiel School of Marine and Atmospheric Science, University of Miami, USA National Center for Atmospheric Research, Boulder, Colorado, USA 07 12 2009 9 23 9237 9247 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/9/9237/2009/acp-9-9237-2009.html The full text article is available as a PDF file from http://www.atmos-chem-phys.net/9/9237/2009/acp-9-9237-2009.pdf

The transport of very short-lived substances into the tropical upper troposphere and lower stratosphere is investigated by a three-dimensional chemical transport model using archived convective updraft mass fluxes (or detrainment rates) from the European Centre for Medium-Range Weather Forecast's ERA-Interim reanalysis. Large-scale vertical velocities are calculated from diabatic heating rates. With this approach we explicitly model the large scale subsidence in the tropical troposphere with convection taking place in fast and isolated updraft events. The model calculations agree generally well with observations of bromoform and methyl iodide from aircraft campaigns and with ozone and water vapor from sonde and satellite observations. Using a simplified treatment of dehydration and bromine product gas washout we give a range of 1.6 to 3 ppt for the contribution of bromoform to stratospheric bromine, assuming a uniform mixing ratio in the boundary layer of 1 ppt. We show that the most effective region for VSLS transport into the stratosphere is the West Pacific, accounting for about 55% of the bromine from bromoform transported into the stratosphere under the supposition of a uniformly distributed source.

 References Chipperfield, M. P.: New Version of the TOMCAT/SLIMCAT Off-Line Chemical Transport Model: Intercomparison of Stratospheric Tracer Experiments, Q. J. Roy. Meteor. Soc., 132, 1179–1203, doi:10.1256/qj.05.51, 2006. Corti. T., Luo, B. P., Peter, T., Fu, Q., and Vömel, H.: Mean radiative energy balance and vertical mass fluxes in the equatorial upper troposphere and lower stratosphere, Geophys. Res. Lett., 32, L06802, doi:10.1029/2004GL021889, 2005. Dessler, A. E.: The effect of deep, tropical convection on the tropical tropopause layer, J. Geophys. Res., 107(D3), 4033, doi:10.1029/2001JD000511, 2002. Dessler, A. E. and Sherwood, S. C.: Effect of convection on the summertime extratropical lower stratosphere, J. Geophys. Res., 109, D23301, doi:10.1029/2004JD005209, 2004. Folkins, I., Kelly, K. K., and Weinstock, E. M.: A simple explanation for the increase in relative humidity between 11 and 14 km in the tropics, J. Geophys. Res., 4736, doi:10.1029/2002JD002185, 2002. Fueglistaler, S., Bonazzola, M., Haynes, P. H., and Peter, T.: Stratospheric water vapor predicted from the Lagrangian temperature history of air entering the stratosphere in the tropics, J. Geophys. Res., 110, D08107, doi:10.1029/2004JD005516, 2005. Fueglistaler, S., Legras, B., Beljaars, A., Morcrette, J.-J., Simmons, A., Tompkins, A. M., and Uppala, S.: The diabatic heat budget of the upper troposphere and lower/mid stratosphere in ECMWF reanalyses, Q. J. Roy. Meteor. Soc., 135(638), 21–37, 2009. Gettelman, A., Randel, W. J., Wu, F., and Massie, S. T.: Transport of water vapor in the tropical tropopause layer, Geophys. Res. Lett., 29(1), 1009, doi:10.1029/2001GL013818, 2002a. Gettelman, A., Salby, M. L., and Sassi F.: The distribution and influence of convection in the tropical tropopause region, J. Geophys. Res., 107(D10), 4080, doi:10.1029/2001JD00104, 2002b. Gettelman, A., Lauritzen, P. H., Park, M., and Kay, J. E.: Processes regulating short-lived species in the tropical tropopause layer, J. Geophys. Res., 114, D13303, doi:10.1029/2009JD011785, 2009. Grooß, J.-U. and Russell, J. M. III: Technical note: A stratospheric climatology for O<sub>3</sub>, H<sub>2</sub>O, CH<sub>4</sub>, NO<sub>x</sub>, HCl and HF derived from HALOE measurements, Atmos. Chem. Phys., 5, 2797–2807, 2005. Hanisco, T. F., Moyer, E. J., Weinstock, E. M., St. Clair, J. M., Sayres, D. S., Smith, J. B., Lockwood, R., Anderson, J. G., Dessler, A. E., Keutsch, F. N., Spackman, J. R., Read, W. G. and Bui, T. P.: Observations of deep convective influence on stratospheric water vapor and its isotopic composition, Geophys. Res. Lett., 34, L04814, doi:10.1029/2006GL027899, 2007. Holton, J. R. and Gettelman, A.: Horizontal transport and the dehydration of the stratosphere, Geophys. Res. Lett., 28, 2799–2802, 2001. Hossaini, R., Chipperfield, M. P., Monge-Sanz, B. M., Richards, N. A. D., Atlas, E. and Blake, D. R.: Bromoform and dibromomethane in the tropics: a 3-D model study of chemistry and transport, Atmos. Chem. Phys. Discuss., 9, 16811–16851, 2009. IFS Documentation – Cy31r1, www.ecmwf.int/research/ifsdocs/CY31r1/PHYSICS/IFSPart4.pdf, last access: 14 August 2009, 2007. Kerkweg, A., Jöckel, P., Warwick, N., Gebhardt, S., Brenninkmeijer, C. A. M., and Lelieveld, J.: Consistent simulation of bromine chemistry from the marine boundary layer to the stratosphere – Part 2: Bromocarbons, Atmos. Chem. Phys., 8, 5919–5939, 2008. Liu, C. and Zipser, E. J.: Global distribution of convection penetrating the tropical tropopause, J. Geophys. Res., 110(D23), D23104, doi:10.1029/2005JD006063, 2005. Marti, J. and Mauersberger, K.: A survey and new measurements of ice vapor pressure at temperatures between 170 and 250 K, Geophys. Res. Lett., 20, 363–366, 1993 McLinden, C. A., Olsen, S. C., Hannegan, B., Wild, O., Prather, M. J., and Sundet, J.: Stratospheric ozone in 3-D models: A simple chemistry and the cross-tropopause flux, J. Geophys. Res., 105(D11), 14653–14665, 2000. Nielsen, J. E. and Douglass, A. R.: A simulation of bromoform's contribution to stratospheric bromine, J. Geophys. Res., 106(D8), 8089–8100, 2001. Quack, B., and Wallace, D. W. R.: Air-sea flux of bromoform: Controls, rates, and implications, Global Biogeochem. Cycles, 17(1), 1023, doi:10.1029/2002GB001890, 2003. Rasch, P. J., Mahowald, N. M., and Eaton, B. E.: Representations of transport, convection, and the hydrologic cycle in chemical transport models: Implications for the modeling of short-lived and soluble species, J. Geophys. Res., 102(D23), 28127–28138, 1997. Read, W. G., Schwartz, M. J., Lambert, A., Su, H., Livesey, N. J., Daffer, W. H., and Boone, C. D.: The roles of convection, extratropical mixing, and in-situ freeze-drying in the tropical tropopause layer, Atmos. Chem. Phys., 8, 6051–6067, 2008. Sinnhuber, B.-M., Weber, M., Amankwah, A., and Burrows, J. P.: Total ozone during the unusual Antarctic winter of 2002, Geophys. Res. Lett., 30(11), 1580, doi:10.1029/2002GL016798, 2003. Sinnhuber, B.-M. and Folkins, I.: Estimating the contribution of bromoform to stratospheric bromine and its relation to dehydration in the tropical tropopause layer, Atmos. Chem. Phys., 6, 4755–4761, 2006. Sinnhuber, B.-M., Sheode, N., Sinnhuber, M., Chipperfield, M. P., and Feng, W.: The contribution of anthropogenic bromine emissions to past stratospheric ozone trends: a modelling study, Atmos. Chem. Phys., 9, 2863–2871, 2009. Thompson, A. M., Witte, J. C., McPeters, R. D., Oltmans, S. J., Schmidlin, F. J., Logan, J. A., Fujiwara, M., Kirchhoff, V. W. J. H., Posny, F., Coetzee, G. J. R., Hoegger, B., Kawakami, S., Ogawa, T., Johnson, B. J., Vömel, H. and Labow, G.: Southern Hemisphere Additional Ozonesondes (SHADOZ) 1998–2000 tropical ozone climatology 1. Comparison with Total Ozone Mapping Spectrometer (TOMS) and ground-based measurements, J. Geophys. Res., 108(D2), 8238, doi:10.1029/2001JD000967, 2003. Warwick, N. J., Pyle, J. A., Carver, G. D., Yang, X., Savage, N. H., O'Connor, F. M., and Cox, R. A.: Global modeling of biogenic bromocarbons, J. Geophys. Res., 111, D24305, doi:10.1029/2006JD007264, 2006. WMO (World Meteorological Organization): Scientific Assessment of Ozone Depletion: 2006, Global Ozone Research and Monitoring Project-Report No. 50, 572 pp., Geneva, Switzerland, 2007.