ACP Atmospheric Chemistry and Physics ACP 1680-7324 Copernicus GmbH Göttingen, Germany 10.5194/acp-9-15-2009 Aerosol and thermodynamic effects on tropical cloud systems during TWPICE and ACTIVE May P. T. 1 Allen G. 2 Vaughan G. 2 Connolly P. 2 Centre for Australian Weather and Climate Research – A partnership between the Bureau of Meteorology and CSIRO, Australia University of Manchester, UK 06 01 2009 9 1 15 24 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/9/15/2009/acp-9-15-2009.html The full text article is available as a PDF file from http://www.atmos-chem-phys.net/9/15/2009/acp-9-15-2009.pdf

Regularly occurring storms over the Tiwi Islands, north of Darwin, Australia are used as a laboratory for investigating the relative importance of thermodynamic parameters, shear and aerosols on the amount and intensity of convection over the islands during the pre-monsoon and monsoon break periods of the 2005–2006 summer wet season. Storm systems on individual days are characterised by simple metrics derived from polarimetric radar data. The analysis shows clear dependencies on thermodynamic and shear parameters. The shear dependence was unexpected, as high shear implied less activity, but this is likely an island effect. There are some indications of a dependence of storm intensity on aerosol, but mid-level moisture differences may also play a role.

 References % vor jede Referenz Allan, J. D., Jimenez, J. L., Williams, P. I., Alfarra, M. E., Bower, K. N, Jayne, J. T., Coe, H., and Worsnop, D. R.: Quantitative sampling using an Aerodyne Mass Spectrometer 1, Techniques of data interpretation and error analysis, J. Geophys. Res. Atmos., 108, 4090–4099, 2003. % vor jede Referenz Allan, J. D., Coe H., Bower, K., N., Alfarra, M. R., Delia, A. E., Jimenez, J. L., Middlebrook, A. M., Drewnick, F., Onasch, T. B., Canagaratna, M. R., Jayne, J. T., and Worsnop, D. R.: A generalised method for the extraction of chemically resolved mass spectra from Aerodyne aerosol mass spectrometer data, J. Aerosol. Sci., 35, 909–922, 2004. % vor jede Referenz Allen, G., Vaughan, G., et al.: Aerosol and trace-gas measurements in the Darwin area during the wet season, J. Geophys. Res., 113, D06306, doi:10.1029/2007JD008706, 2008. % vor jede Referenz Ben Liley, J., Baumgardner, D., Kondo, Y., Kita, K., Blake, D. R., Koike, M., Machida, T., Takegawa, N., Kawakami, S., Shirai T., and Ogawa, T.: Black carbon in aerosol during BIBLE B, J. Geophys. Res., 108, 8399, doi:10.1029/2001JD000845, 2003. % vor jede Referenz Brandes, E. A., Zhang, G., and Vivekanandan, J.: Drop size distribution retrieval with polarimetric radar, model and application, J. Appl. Meteor., 43, 461–475, 2004. % vor jede Referenz Carbone, R. E., Wilson, J. W., Keenan, T. D., and Hacker, J. M.: Tropical island convection in the absence of significant topography Part I, Life cycle of diurnally forced convection, Mon. Weather Rev., 128, 3459–3480, 2000. % vor jede Referenz Carey, L. D. and Rutledge, S. A.: The relationship between precipitation and lightning in tropical island convection, A C-band polarimetric radar study, Mon. Weather Rev., 128, 2687–2710, 2000. % vor jede Referenz Cotton, W. R., Zhang, H., McFarquhar, G. M., and Saleeby, S. M: Should we consider polluting Hurricanes to reduce their intensity?, J. Wea. Modif., 39, 70–73, 2007. % vor jede Referenz Crook, N. A.: Understanding Hector, The dynamics of island thunderstorms, Mon. Weather Rev., 129, 1550–1563, 2001. % vor jede Referenz Drosdowsky, W.: Variability of the Australian summer monsoon at Darwin, 1957–1992, J. Clim., 9, 85–96, 1996. % vor jede Referenz Golding, B. W.: A numerical investigation of tropical island thunderstorms, Mon. Weather Rev., 121, 1417–1433, 2003. % vor jede Referenz Jimenez, J. L., Jayne, J. T., Shi Q., et al.: Ambient aerosol sampling using the Aerodyne Mass Spectrometer, J. Geophys. Res., 108, 8425–8437, 2003. % vor jede Referenz Keenan, T. D.: Hydrometeor classification with a C-band polarimetric radar, Aust. Meteor. Mag., 52, 23–31, 2003. % vor jede Referenz Keenan, T. D. and Carbone, R. E.: A preliminary morphology of precipitation systems in tropical northern Australia, Quart. J. Roy. Meteor. Soc., 118, 283–326, 1992. % vor jede Referenz Keenan, T. D., Morton, B. R., Manton, M. J., and Holland, G. J.: The Island Thunderstorm Experiment (ITEX) – A study of tropical thunderstorms in the Maritime Continent, Bull. Amer. Meteor. Soc., 70, 152–159, 1989. % vor jede Referenz Keenan, T. D., Glasson, K., Cummings, F., Bird, T. S., Keeler, J. and Lutz, J.: The BMRC/NCAR C-Band polarimetric (C-POL) radar system., J. Atmos. Oceanic Tech., 15, 871–886, 1998. % vor jede Referenz Keenan, T. D., Rutledge, S. A., et al.: The Maritime Continent Thunderstorm Experiment (MCTEX), Overview and some results, Bull. Amer. Meteor. Soc., 81, 2433–2455, 2000. % vor jede Referenz Khain, A., Rosenfeld, D., and Pokrovsky, A.: Aerosol impact on the dynamics and microphysics of deep convective clouds, Quart. J. Roy. Meteor. Soc., 131, 2639–2663, doi:10.1256/qj.04.62, 2005 % vor jede Referenz Koren, I., Kaufman, Y. J., Rosenfeld, D., Remer, L., and Rudich, Y.: Aerosol invigoration and restructuring of Atlantic convective clouds, Geophys. Res. Lett., 32, L14828, doi:10.1029/2005GL023187, 2005. % vor jede Referenz LeMone, M. A., Zipser, E. J., and Trier, S. B.: The role of environmental shear and thermodynamic conditions in determining the structure and evolution of mesoscale convective systems during TOGA COARE, J. Atmos. Sci, 55, 3493–3518, 1998. % vor jede Referenz Luhar, A. K., Mitchell, R. M., Meyer, C.H., Campbell, S. K., and Gras, J. L.: Biomass burning emissions over Northern Australia constrained by aerosol measurements II – Model validation and impacts on air quality and climate, Atmos. Environ., 42, 1647–1664, 2008. % vor jede Referenz May, P. T. and Keenan, T. D.: Evaluation of microphysical retrievals from polarimetric radar with wind profiler data, J. Appl. Meteor., 44, 827–838, 2005. % vor jede Referenz May, P. T. and Lane, T. P.: A method for using weather radar data to test cloud resolving models, Met. Appl., submitted, 2008. % vor jede Referenz May, P. T., Mather, J. H., Vaughan, G., Jakob, C., McFarquhar, G. M., Bower, K. N., and Mace, G. G.: The Tropical Warm Pool International Cloud Experiment (TWPICE), Bull. Amer. Meteor. Soc., 89, 629–645, 2008. % vor jede Referenz Moncrieff, M. W. and Liu, C.: Convection initiation by density currents, Role of convergence, shear, and dynamical organization, Mon. Weather Rev., 121, 2455–2464, 1999. % vor jede Referenz Rosenfeld, D. and Lensky, I. M.: Satellite-based insights into precipitation formation processes in continental and maritime convective clouds, Bull. Amer. Meteor. Soc., 79, 2457–2476, 1998. % vor jede Referenz Rotunno, R., Klemp, J. B., and Wiseman, M. L.: A theory for strong long-lived squall lines, J. Atmos. Sci., 45, 463–485, 1998. % vor jede Referenz Saito, K., Keenan, T. D., Holland, G., and Puri, K.: Numerical simulation of the diurnal evolution of tropical island convection over the maritime continent, Mon. Weather Rev., 129, 378–400, 2001. % vor jede Referenz Schafer, R., May, P. T., Keenan, T. D., McGuffie, K., Ecklund, W. L., Johnson, P. J., and Gage, K. S.: Island boundary layer development over a tropical island during the Maritime Continent Thunderstorm Experiment (MCTEX), J. Atmos. Sci., 58, 2163–2179, 2001. % vor jede Referenz Simpson, J., Keenan, T. D., Ferrier, B., Simpson, R. H., and Holland, G. J.: Cumulus mergers in the maritime continent, Meteor. Atmos. Phys., 51, 73–99, 1993. % vor jede Referenz Steiner, M., Houze, R. A. Jr, and Yuter, S. E.: Climatological characterization of three-dimensional storm structure from operational radar and rain gauge data, J. Appl. Meteor., 34, 1978–2007, 1995. % vor jede Referenz Straka, J. M., Zrnic, D., and Ryzhkov, A.: Bulk hydrometeor classification and quantification using polarimetric radar data, Synthesis of relations, J. Appl. Meteor., 39, 1341–1372, 2000. % vor jede Referenz Vaughan, G., Schiller, C., MacKenzie, A. R., Bower, K., Peter, T., Schlager, H., Harris, N. R. P., and May, P. T.: Studies in a natural laboratory, High-altitude aircraft measurements around deep tropical convection, Bull. Amer. Meteor. Soc., 89, 647–662, 2008. % vor jede Referenz Van Den Heever, S. C., Carrio, G. G., Cotton, W. R., deMott, P. J. and, Prenni, A. J.: Impacts of nucleating aerosol on Florida storms Part I, Mesoscale simulations, J. Atmos. Sci, 63, 1752–1775, 2006. % vor jede Referenz Weckwerth, T. M.: The effect of small-scale moisture variability on thunderstorm initiation, Mon. Weather Rev., 128, 4017–4030, 2000. % vor jede Referenz Weisman, M. L. and Klemp, J. B.: The dependence of numerically simulated convective storms on vertical wind shear and buoyance, Mon. Weather Rev., 110, 504–520, 1982. % vor jede Referenz Williams, C. R. and May, P. T.: Uncertainties in Profiler and Polarimetric DSD Estimates and their Relation to Rainfall Uncertainties, J. Atmos. Oceanic Tech., 25, 1881–1887, 2008. % vor jede Referenz Wilson, J. W., Carbone, R. E., Tuttle, J. D., and Keenan, T. D.: Tropical island convection in the absence of significant topography Part II: Nowcasting storm evolution, Mon. Weather Rev., 129, 1637–1655, 2001. % vor jede Referenz Zrnic, D. S. and Ryzhkov, A.: Polarimetry for weather surveillance radars, Bull. Amer. Meteor. Soc., 80, 389–406, 1999.