ACP Atmospheric Chemistry and Physics ACP 1680-7324 Copernicus GmbH Göttingen, Germany 10.5194/acp-11-2557-2011 Investigations of aerosol impacts on hurricanes: virtual seeding flights Carrio G. G. 1 Cotton W. R. 1 Department of Atmospheric Science, Colorado State University, Fort Collins, CO 80523, USA 18 03 2011 11 6 2557 2567 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/11/2557/2011/acp-11-2557-2011.html The full text article is available as a PDF file from http://www.atmos-chem-phys.net/11/2557/2011/acp-11-2557-2011.pdf

This paper examines the feasibility of mitigating the intensity of hurricanes by enhancing the CCN concentrations in the outer rainband region. Increasing CCN concentrations would cause a reduced collision and coalescence, resulting in more supercooled liquid water to be transported aloft which then freezes and enhances convection via enhanced latent heat of freezing. The intensified convection would condense more water ultimately enhancing precipitation in the outer rainbands. Enhanced evaporative cooling from the increased precipitation in the outer rainbands would produce stronger and more widespread areal cold pools which block the flow of energy into the storm core, ultimately inhibiting the intensification of the tropical cyclone. <br></br> We designed a series of multi-grid for which the time of the "virtual flights" as well as the aerosol release rates are varied. A code that simulates the flight of a plane is used to increase the CCN concentrations as an aircraft flies. Results show a significant sensitivity to both the seeding time and the aerosol release rates and support the aforementioned hypothesis.

 References Bister, M.: Effect of the Coriolis parameter on tropical cyclogenesis: The dominant role of outer convection, J. Atmos. Sci., 58, 3463–3476, 1997. Bister, M.: Effect of Peripheral Convection on Tropical Cyclone Formation. Preprints, 22d, Conf. on Hurricanes and Tropical Meteorology, Fort Collins, CO, Amer. Meteor. Soc., 553–554, 2001. Carrió, G. G., Cotton, W. R., and Cheng W. Y. Y.: Urban growth and aerosol effects on convection over Houston, Part I: the August 2000 case, Atmos. Res., 96, 560–574, 2010 Carrió, G.G. and Cotton, W. R.: Effects of the Urban growth of Houston on convection and precipitation, Part II: Dependence of aerosol effects on instability, Atmos. Res., submitted, 2010. Carrió, G. G., van den Heever, S. C., and Cotton, W.R.: Impacts of nucleating aerosol on anvil-cirrus clouds: A modeling study, Atmos. Res., 84, 111–131, 2007. Cotton, W. R. and Pielke, R. A.: Human impacts on weather and climate, Cambridge University Press, New York, USA, 288~pp., 2009. Cotton, W. R., Pielke Sr., R. A., Walko, R. L., Liston, G. E., Tremback, C. J., Jiang, H., McAnelly, R. L., Harrington, J. Y., Nicholls, M. E., Carrió, G. G., and McFadden, J. P.: RAMS 2001: Current status and future directions, Meteor. Atmos. Phys., 82, 5–29, 2003. Cotton, W. R., Zhang, H., McFarquhar, G. M., and Saleeby, S. M.: Should we consider polluting hurricanes to reduce their intensity?, J. Wea. Mod., 39, 70–73, 2007 Feingold, G. and Heymsfield, A. J.: Parameterizations of condensational growth of droplets fior use in general circulation models, J. Atmos. Sci., 49, 2325–2342, 1992. Frisius, T. and Hasselbeck, T.: The effect of latent cooling processes in tropical cyclone simulations, Q. J. Roy. Meteor. Soc., 135, 1732–1749, 2009. Hobbs, P. V., Politovich, M. K., and Radke, L. F.: The structures of summer convective clouds in eastern Montana, I, Natural clouds, J. Appl. Meteor., 19, 645–663, 1980. Khain A. P., Rosenfeld, D., and Pokrovsky, A.: Simulation of deep convective clouds with sustained supercooled liquid water down to $-$37.5° C using a spectral microphysics model, Geophys. Res. Lett., 28, 3887–3890, 2001. Khain, A., Pokrovsky, A., and Pinsky, M., Seifert, A., and Phillips, V.: Effects of atmospheric aerosols on deep convective clouds as seen from simulations using a spectral microphysics mixed-phase cumulus cloud model Part 1: Model description, J. Atmos. Sci, 61, 2963–2982, 2004. Khain, A., Rosenfeld, D., and Pokrovsky, A.: Aerosol impact on the dynamics and microphysics of convective clouds, Q. J. Roy. Meteor. Soc., 131, 2639–2663, 2005. Khain, A., Cohen, N., Lynn, B., and Pokrovsky, A.: Possible aerosol effects on lightning activity and structure of hurricanes, J. Atmos. Sci., 65, 3652–3667, 2008. Khain, A. P.: Effects of aerosols on precipitation: a review: Environ. Res. Lett., Environ. Res. Lett., 4, 015004, http://dx.doi.org/10.1088/1748-9326/4/1/015004doi:10.1088/1748-9326/4/1/015004, 2009. Khain, A., Lynn, B., and Dudhia, J.: Aerosol effects on intensity of landfalling hurricanes as seen from simulations with WRF model with spectral bin microphysics, J. Atmos. Sci. 67, 365–384, 2010. Lerach, D., Gaudet, B.J., and Cotton, W. R.: Idealized simulations of aerosol influences on tornadogenesis, Geophys. Res. Lett., 35, L23806, 6~pp., http://dx.doi.org/10.1029/2008GL035617doi:10.1029/2008GL035617, 2008. Levin, Z. and Cotton, W. R (Eds.): Aerosol Pollution Impact on Precipitation: A Scientific Review, Springer, Heidelberg and Karlsruhe, Germany, 386~pp., 2009. Lynn, B., Khain, A., Dudhia, J., Rosenfeld, D., Pokrovsky, A., and Seifert, A: Spectral~(bin) microphysics coupled with a mesoscale model~(MM5), Part 2: Simulation of a CaPe rain event with squall line, Mon. Weather Rev., 133, 59–71, 1997. Meyers, M. P. Walko, R. L., Harrington J. Y., and Cotton, W. R.: New Rams cloud microphyisics parameterization: Part II, The two-moment scheme, Atmos. Res., 45, 3–39, 2005. Mitchell, D. L., Macke, A., and Liu, Y.: Modeling cirrus clouds, part II, Treatment of radiative properties, J. Atmos. Sci., 53, 2967–2988, 1996. O'Dowd, C. D., Smith, M. E., Consterdine, I. E., and Lowe, J. A.: Marine aerosol, sea-salt, and the marine sulphur cycle: A short review, Atmos. Environ., 31, 73–80, 1997. Pielke, R. A., Cotton, W. R., Walko, R. L., Tremback, C. J., Lyons, W. A., Grasso, L. D., Nicholls, M. E., Moran, M. D., Wesley, D. A., Lee, T. J., Copeland, J. H.: A comprehensive meteorological modeling system-RAMS, Meteorol. Atmos. Phys., 49, 69–91, 1992. Riemer, M., Montgomery, M. T., and Nicholls, M. E.: A new paradigm for intensity modification of tropical cyclones: thermodynamic impact of vertical wind shear on the inflow layer, Atmos. Chem. Phys., 10, 3163–3188, http://dx.doi.org/10.5194/acp-10-3163-2010doi:10.5194/acp-10-3163-2010, 2010. Ritter, B. and Geleyn, J. F.: A comprehensive radiation scheme for numerical weather prediction models with potential applications in climate simulations, Mon. Weather Rev., 120, 303–325, 1992. Rosenfeld, D. and Khain, A: Anthropogenic aerosol invigorating hail, 2008, Proc. Int. Conf. on Clouds and Precipitation~(Cancun, July 2008), 2008. Rosenfeld, D., Khain, A., Lynn, B., and Woodley, W. L.: Simulation of hurricane response to suppression of warm rain by sub-micron aerosols, Atmos. Chem. Phys., 7, 3411–3424, http://dx.doi.org/10.5194/acp-7-3411-2007doi:10.5194/acp-7-3411-2007, 2007. Saleeby, S. M. and Cotton, W. R.: A large-droplet model and prognostic number concentration of cloud droplets in the RAMS@CSU model. Part I: Module descriptions and Supercell test simulations, J. Appl. Meteorol., 43, 182–195, 2004. Saleeby, S. M. and Cotton, W. R.: A Binned Approach to Cloud-Droplet Riming Implemented in a Bulk Microphysics Model, J. Appl. Meteorol., 47, 694–703, 2008. Seifert, A. and Beheng, K.: A two-moment cloud microphysics parameterization for mixed-phase clouds, Part II: maritime versus continental deep convective storms, Meteorol. Atmos. Phys., 92 67–88, 2006. Slingo, A. and Schreckner, M.: On shortwave properties of stratiform water clouds, Q. J. Roy. Meteor. Soc., 108, 407–426, 1982. van den Heever, S. and Cotton, W. R.: Urban aerosol impacts on downwind convective storms, J. Appl. Met., 46, 828–850, 2007. van den Heever, S. C., Carrió, G. G., Cotton, W. R., DeMott, P. J., and Prenni, A. J.: Impacts of nucleating aerosol on Florida convection, Part I: Mesoscale Simulations, J. Atmos. Sci., 63, 1752–1775, 2006. Wang, Y.: An Explicit Simulation of Tropical Cyclones with a Triply Nested Movable Mesh Primitive Equation Model: TCM3, Part II: Model Refinements and Sensitivity to Cloud Microphysics Parameterization, Mon. Weather Rev., 130, 12, 3022–3036, 2002. Wang, C.: A modeling study of the response of tropical deep convection to the increase of cloud condensational nuclei concentration: 1. Dynamics and microphysics, J. Geophys. Res., 110, D21211, http://dx.doi.org/10.1029/2004JD005720doi:10.1029/2004JD005720, 2005. Zhang, H., McFarquhar, G. M., Saleeby, S. M., and Cotton, W. R.: Impacts of Saharan dust as CCN on the evolution of an idealized tropical cyclone, Geophys. Res. Lett., 34, L14812, http://dx.doi.org/10.1029/2007GL029876doi:10.1029/2007GL029876, 2005. Zhang, H., McFarquhar, G. M., Cotton, W. R., and Deng, Y.: Direct and indirect impacts of Saharan dust acting as cloud condensation nuclei on tropical cyclone eyewall development, Geophys. Res. Lett., 36, L06802, http://dx.doi.org/10.1029/2009GL037276doi:10.1029/2009GL037276, 2009.