ACP Atmospheric Chemistry and Physics ACP 1680-7324 Copernicus GmbH Göttingen, Germany 10.5194/acp-10-11175-2010 Modelling deep convection and its impacts on the tropical tropopause layer Hosking J. S. 1 3 Russo M. R. 2 Braesicke P. 2 Pyle J. A. 2 Centre for Atmospheric Science, University of Cambridge, Cambridge, UK NCAS, University of Cambridge, Cambridge, UK now at: the British Antarctic Survey, Cambridge, UK 26 11 2010 10 22 11175 11188 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/10/11175/2010/acp-10-11175-2010.html The full text article is available as a PDF file from http://www.atmos-chem-phys.net/10/11175/2010/acp-10-11175-2010.pdf

The UK Met Office's Unified Model is used at a climate resolution (N216, ~0.83°×~0.56°, ~60 km) to assess the impact of deep tropical convection on the structure of the tropical tropopause layer (TTL). We focus on the potential for rapid transport of short-lived ozone depleting species to the stratosphere by rapid convective uplift. The modelled horizontal structure of organised convection is shown to match closely with signatures found in the OLR satellite data. In the model, deep convective elevators rapidly lift air from 4–5 km up to 12–14 km. The influx of tropospheric air entering the TTL (11–12 km) is similar for all tropical regions with most convection stopping below ~14 km. The tropical tropopause is coldest and driest between November and February, coinciding with the greatest upwelling over the tropical warm pool. As this deep convection is co-located with bromine-rich biogenic coastal emissions, this period and location could potentially be the preferential gateway for stratospheric bromine.

 References Aumann, H H. and DeSouza-Machado, S G.: Deep convective clouds at the tropopause, Atmos. Chem. Phys. Discuss., 10, 16475–16496, \doi10.5194/acpd-10-16475-2010, 2010. Brewer, A.: Evidence for a world circulation provided by the measurements of helium and water vapour distribution in the Stratosphere, Q. J. Roy. Meteorolog. Soc., 75, 351–63, 1949. Corti, T., Luo, B P., de~Reus, M., Brunner, D., Cairo, F., Mahoney, M J., Martucci, G., Matthey, R., Mitev, V., dos Santos, F H., Schiller, C., Shur, G., Sitnikov, N M., Spelten, N., Vössing, H J., Borrmann, S., and Peter, T.: Unprecedented evidence for deep convection hydrating the tropical stratosphere, Geophys. Res. Lett., 35, L10810, \doi10.1029/2008GL033641, 2008. Danielsen, E F.: In situ evidence of rapid, vertical, irreversible transport of lower tropospheric air into the lower tropical stratosphere by convective cloud turrets and by larger-scale upwelling in tropical cyclones, J. Geophys. Res.-Atmos., 98, 8665–8681, 1993. Davies, T., Cullen, M., Malcolm, A., Mawson, M., Staniforth, A., White, A., and Wood, N.: A new dynamical core for the Met Office's global and regional modelling of the atmosphere, Q. J. Roy. Meteorol. Soc., 131, 1759–1782, \doi10.1256/qj.04.101, 2005. Edwards, J. and Slingo, A.: Studies with a flexible new radiation code. I: Choosing a configuration for a large-scale model, Q. J. Roy. Meteorol. Soc., 122, 689–719, 1996. Essery, R. L H., Best, M J., Betts, R A., Cox, P M., and Taylor, C M.: Explicit representation of subgrid heterogeneity in a GCM land surface scheme, J. Hydrometeorol., 4, 530–543, 2003. Folkins, I., Loewenstein, M., Podolske, J., Oltmans, S., and Proffitt, M.: A barrier to vertical mixing at 14 km in the tropics: Evidence from ozonesondes and aircraft measurements, J. Geophys. Res.-Atmos., 104, 22095–22102, 1999. Folkins, I., Oltmans, S., and Thompson, A.: Tropical convective outflow and near surface equivalent potential temperatures, Geophys. Res. Lett., 27, 2549–2552, 2000. Fritsch, J. and Chappell, C.: Numerical prediction of convectively driven mesoscale pressure systems. I: Convective parameterization, J. Atmos. Sci., 37, 1722–1733, 1980a. Fritsch, J. and Chappell, C.: Numerical prediction of convectively driven mesoscale pressure systems. II: Mesoscale model, J. Atmos. Sci., 37, 1734–1762, 1980b. Fueglistaler, S., Wernli, H., and Peter, T.: Tropical troposphere-to-stratosphere transport inferred from trajectory calculations, J. Geophys. Res.-Atmos., 109, D03108, \doi10.1029/2003JD004069, 2004. Fueglistaler, S., Dessler, A E., Dunkerton, T J., Folkins, I., Fu, Q., and Mote, P W.: Tropical tropopause layer, Rev. Geophys., 47, RG1004, \doi10.1029/2008RG000267, 2009. Gage, K S., Mcafee, J R., Carter, D A., Ecklund, W L., Riddle, A C., Reid, G C., and Balsley, B B.: Long-term mean vertical motion over the tropical Pacific – wind-profiling Doppler radar measurements, Science, 254, 1771–1773, 1991. Gettelman, A. and Forster, P M.: A climatology of the tropical tropopause layer, J. Meteor. Res. Jpn., 80, 911–924, 2002. Gettelman, A., Salby, M., and Sassi, F.: Distribution and influence of convection in the tropical tropopause region, J. Geophys. Res.-Atmos., 107(D10), 4080, \doi10.1029/2001JD001048, 2002. Gettelman, A., Forster, P., Fujiwara, M., Fu, Q., Vomel, H., Gohar, L., Johanson, C., and Ammerman, M.: Radiation balance of the tropical tropopause layer, J. Geophys. Res.-Atmos., 109, D07103, \doi10.1029/2003JD004190, 2004. Grant, A.: Cloud-base fluxes in the cumulus-capped boundary layer, Q. J. Roy. Meteorol. Soc., 127, 407–421, 2001. Grant, A. L M. and Brown, A R.: A similarity hypothesis for shallow-cumulus transports, Q. J. Roy. Meteorol. Soc., 125, 1913–1936, 1999. Gregory, D. and Rowntree, P.: A mass flux convection scheme with representation of cloud ensemble characteristics and stability-dependent closure, Mon. Weather Rev., 118, 1483–1506, 1990. Highwood, E J. and Hoskins, B J.: The tropical tropopause, Q. J. Roy. Meteorol. Soc., 124, 1579–1604, 1998. Holton, J. and Gettelman, A.: Horizontal transport and the dehydration of the stratosphere, Geophys. Res. Lett., 28, 2799–2802, 2001. Holton, J R., Haynes, P H., McIntyre, M E., Douglass, A R., Rood, R B., and Pfister, L.: Stratosphere-troposphere exchange, Rev. Geophys., 33, 403–439, 1995. Hoyle, C R., Marécal, V., Russo, M R., Arteta, J., Chemel, C., Chipperfield, M P., D'Amato, F., Dessens, O., Feng, W., Harris, N. R P., Hosking, J S., Morgenstern, O., Peter, T., Pyle, J A., Reddmann, T., Richards, N. A D., Telford, P J., Tian, W., Viciani, S., Wild, O., Yang, X., and Zeng, G.: Tropical deep convection and its impact on composition in global and mesoscale models – Part 2: Tracer transport, Atmos. Chem. Phys. Discuss., 10, 20355–20404, \doi10.5194/acpd-10-20355-2010,, 2010. Levine, J G., Braesicke, P., Harris, N. R P., Savage, N H., and Pyle, J A.: Pathways and timescales for troposphere-to-stratosphere transport via the tropical tropopause layer and their relevance for very short lived substances, J. Geophys. Res.-Atmos., 112, D04308, \doi10.1029/2005JD006940, 2007. Li, D. and Shine, P.: A 4-Dimensional Ozone Climatology for UGAMP Models, UGAMP Internal Report, 1995. Liebmann, B. and Smith, C A.: Description of a complete (interpolated) outgoing longwave radiation dataset, B. Am. Meteorol. Soc., 77, 1275–1277, 1996. Liu, C T. and Zipser, E J.: Global distribution of convection penetrating the tropical tropopause, J. Geophys. Res.-Atmos., 110, D23104, \doi10.1029/2005JD006063, 2005. Lock, A P., Brown, A R., Bush, M R., Martin, G M., and Smith, R. N B.: A new boundary layer mixing scheme. Part I: Scheme description and single-column model tests, Mon. Weather Rev., 128, 3187–3199, 2000. Martin, G M., Ringer, M A., Pope, V D., Jones, A., Dearden, C., and Hinton, T J.: The physical properties of the atmosphere in the new Hadley Centre Global Environmental Model (HadGEM1). Part I: Model description and global climatology, J. Climate, 19, 1274–1301, 2006. Mote, P., Rosenlof, K., McIntyre, M., Carr, E., Gille, J., Holton, J., Kinnersley, J., Pumphrey, H., Russell, J., and Waters, J.: An atmospheric tape recorder: The imprint of tropical tropopause temperatures on stratospheric water vapor, J. Geophys. Res.-Atmos., 101, 3989–4006, 1996. Nazaryan, H., McCormick, M P., and Menzel, W P.: Global characterization of cirrus clouds using CALIPSO data, J. Geophys. Res.-Atmos., 113, D16211, \doi10.1029/2007JD009481, 2008. Newell, R. and Gould-Stewart, S.: A Stratospheric Fountain, J. Atmos. Sci, 38, 2789–2796, 1981. Norton, W A.: Longwave Heating of the Tropical Lower Stratosphere, Geophys. Res. Lett., 28(19), 3653-3656, \doi10.1029/2001GL013379, 2001. Parker, D., Jackson, M., and Horton, E B.: The 1961-1990 GISST2.2 Sea Surface Temperature and Sea Ice Climatology, The Hadley Centre Climate Research Technical Note No. 63, 1995. Petch, J C., Willett, M., Wong, R Y., and Woolnough, S J.: Modelling suppressed and active convection. Comparing a numerical weather prediction, cloud-resolving and single-column model, Q. J. Roy. Meteorol. Soc., 133, 1087–1100, \doi10.1002/qj.109, 2007. Ricaud, P., Barret, B., Attie, J L., Motte, E., Le~Flochmoeen, E., Teyssedre, H., Peuch, V H., Livesey, N., Lambert, A., and Pommereau, J P.: Impact of land convection on troposphere-stratosphere exchange in the tropics, Atmos. Chem. Phys., 7, 5639–5657, \doi10.5194/acpd-7-5639-2007, 2007. Romps, D M. and Kuang, Z.: Overshooting convection in tropical cyclones, Geophys. Res. Lett., 36, L09804, \doi10.1029/2009GL037396, 2009. Rossow, W B. and Pearl, C.: 22-Year survey of tropical convection penetrating into the lower stratosphere, Geophys. Res. Lett., 34, L04803, \doi10.1029/2006GL028635, 2007. Russo, M R., Marécal, V., Hoyle, C R., Arteta, J., Chemel, C., Chipperfield, M P., Dessens, O., Feng, W., Hosking, J S., Telford, P J., Wild, O., Yang, X., and Pyle, J A.: Tropical deep convection and its impact on composition in global and mesoscale models - Part 1: Meteorology and comparison with observations., Atmos. Chem. Phys. Discuss., 10, 19469–19514, \doi10.5194/acpd-10-19469-2010, 2010. Salawitch, R., Weisenstein, D., Kovalenko, L., Sioris, C., Wennberg, P., Chance, K., Ko, M., and McLinden, C.: Sensitivity of ozone to bromine in the lower stratosphere, Geophys. Res. Lett., 32, L05811, \doi10.1029/2004GL021504, 2005. Sassen, K., Wang, Z., and Liu, D.: Global distribution of cirrus clouds from CloudSat/Cloud‐Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) measurements, J. Geophys. Res.-Atmos., 113, D00A12, \doi10.1029/2008JD009972, 2008. Schwartz, M J., Lambert, A., Manney, G L., Read, W G., Livesey, N J., Froidevaux, L., Ao, C O., Bernath, P F., Boone, C D., Cofield, R E., Daffer, W H., Drouin, B J., Fetzer, E J., Fuller, R A., Jarnot, R F., Jiang, J H., Jiang, Y B., Knosp, B W., Krueger, K., Li, J. L F., Mlynczak, M G., Pawson, S., Russell, J M., I., Santee, M L., Snyder, W V., Stek, P C., Thurstans, R P., Tompkins, A M., Wagner, P A., Walker, K A., Waters, J W., and Wu, D L.: Validation of the Aura Microwave Limb Sounder temperature and geopotential height measurements, J. Geophys. Res.-Atmos., 113, D15S11, \doi10.1029/2007JD008783, 2008. Seidel, D., Ross, R., Angell, J., and Reid, G.: Climatological characteristics of the tropical tropopause as revealed by radiosondes, J. Geophys. Res.-Atmos., 106, 7857–7878, 2001. Sherwood, S C. and Dessler, A E.: On the control of stratospheric humidity, Geophys. Res. Lett., 27, 2513–2516, 2000. Sherwood, S C. and Dessler, A E.: A model for transport across the tropical tropopause, J. Atmos. Sci., 58, 765–779, 2001. 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, doi:10.5194/acp-6-4755-2006, 2006. Thuburn, J. and Craig, G.: On the temperature structure of the tropical substratosphere, J. Geophys. Res.-Atmos., 107(D2), 4017, \doi10.1029/2001JD000448, 2002. Wilson, D R. and Ballard, S P.: A microphysically based precipitation scheme for the UK Meteorological Office Unified Model, Q. J. Roy. Meteorol. Soc., 125, 1607–1636, 1999. WMO: (World Meteorological Organization), Scientific Assessment of Ozone Depletion: 2006, Global Ozone Research and Monitoring Project – Report No. 50, Geneva, Switzerland, 572 pp., 2007. Xie, P. and Arkin, P.: Global precipitation: A 17-year monthly analysis based on gauge observations, satellite estimates, and numerical model outputs, Bull. Am. Meteorol. Soc., 78, 2539–2558, 1997. Yokouchi, Y., Hasebe, F., Fujiwara, M., Takashima, H., Shiotani, M., Nishi, N., Kanaya, Y., Hashimoto, S., Fraser, P., Toom-Sauntry, D., Mukai, H., and Nojiri, Y.: Correlations and emission ratios among bromoform, dibromochloromethane, and dibromomethane in the atmosphere, J. Geophys. Res., 110, \doi10.1029/2005JD006303, 2005. Yulaeva, E., Holton, J R., and Wallace, J M.: On the cause of the annual cycle in tropical lower-stratospheric temperatures, J. Atmos. Sci., 51, 169–174, 1994.