References

ACPD

Atmospheric Chemistry and Physics Discussions

ACPD

1680-7375

Copernicus GmbH

Göttingen, Germany

10.5194/acpd-7-5647-2007

Simulation of hurricane response to suppression of warm rain by sub-micron aerosols

Rosenfeld

¹ Khain

¹ Lynn

¹ Woodley

W. L.

Institute of Earth Sciences, The Hebrew University of Jerusalem, Isreal

Woodley Weather Consultants, 11 White Fir Court, Littleton 80327, USA

26 04 2007

7 2 5647 5674

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The feasibility of hurricane modification was investigated for hurricane Katrina using the Weather Research and Forecasting Model (WRF). The possible impact of seeding of clouds with submicron cloud condensation nuclei (CCN) on hurricane structure and intensity as measured by nearly halving of the area covered by hurricane force winds was simulated by "turning–off" warm rain formation in the clouds at Katrina's periphery (where wind speeds were less than 22 m s<sup>−1</sup>). This simplification of the simulation of aerosol effects is aimed at evaluating the largest possible response. This resulted in the weakening of the hurricane surface winds compared to the "non-seeded" simulated storm during the first 24 h within the entire tropical cyclone (TC) area compared to a control simulation without warm rain suppression. Later, the seeding-induced evaporative cooling at the TC periphery led to a shrinking of the eye and hence to some increase in the wind within the small central area of the TC. Yet, the overall strength of the hurricane decreased in response to the suppressed warm rain at the periphery, as measured by a 25% reduction in the radius of hurricane force winds. In a simulation with warm rain suppression throughout the hurricane, the relative weakening compared to the control continued throughout the simulations and the eye shrunk even further. This shows that the main mechanism by which suppressing warm rain weakens the TC is the low level evaporative cooling of the un-precipitated cloud drops and the added cooling due to melting of precipitation that falls from above.

References 1

Andreae, M. O., Rosenfeld, D., Artaxo, P., Costa, A., Frank, G. P., Longo, K. M., and Silva-Dias, M. A. F.: Smoking rain clouds over the Amazon, Science, 303, 1337–1342, 2004.

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., Carrio, G. G., and McFadden, J. P.: RAMS 2001: Current status and future directions, Meteorol. 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., in press, 2007.

Falkovich, A. I., Khain, A. P., and Ginis, I. D.: The influence of the air-sea interaction on the development and motion of a tropical cyclone: numerical experiments with a triply nested model, Meteorol. Atmos. Phys., 55, 167–84, 1995.

Fiorino, M. and Elsberry, R. L.: Some aspects of vortex structure related to the tropical cyclone motion, J. Atmos. Sci., 47, 975–990, 1989.

Houze Jr., R. A., Chen, S. S., Smull, B. F., Lee, W. C., and Bell, M. M.: Hurricane intensity and eyewall replacement, Science, 315, 1235–1239, 2007.

Kain, J. S. and Fritsch J. M.: Convective parameterization for mesoscale models: The Kain-Fritsch scheme. The Representation of Cumulus Convection in Numerical Models, edited by: Emanuel, K. A. and Raymond, D., Amer. Meteorol. Soc., 246 pp, 1993.

Khain, A. P. and Ginis, I. D.: The mutual response of a moving tropical cyclone and the ocean, Beitr. Phys. Atmos., 64, 125–142, 1991.

Khain, A. P., Pokrovsky, A., 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. P., Rosenfeld, D., and Pokrovsky, A.: Aerosol impact on the dynamics and microphysics of convective clouds, Quart. J. Roy. Meteorol. Soc., 131, 2639–2663, 2005.

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. Wea. Rev., 133, 59–71, 2005.

Michalakes, J., Dudhia, J., Gill, D., Henderson, T., Klemp, J., Skamarock W., and Wang, W.: The Weather Research and Forecast Model: Software Architecture and Performance, Proceedings of the Eleventh ECMWF Workshop on the Use of High Performance Computing in Meteorology, edited by: Zwieflhofer, W. and Mozdzynski, G., World Scientific, pp 156–168, 2005.

Michalakes, J., Chen, S., Dudhia, J., Hart, L., Klemp, J., Middlecoff, J., and Skamarock, W.: Development of a Next Generation Regional Weather Research and Forecast Model. Developments in Teracomputing: Proceedings of the Ninth ECMWF Workshop on the Use of High Performance Computing in Meteorology, edited by: Zwieflhofer, W. and Kreitz, N., World Scientific, pp. 269–276, 2001.

Nong, S. and Emanuel, K.: A numerical study of the genesis of concentric eyewalls in hurricanes, Quart. J. Roy. Meteorol. Soc., 129, 3323–338, 2003.

Rosenfeld, D.: TRMM Observed First Direct Evidence of Smoke from Forest Fires Inhibiting Rainfall, Geophys. Res. Lett., 26(20), 3105–3108, 1999.

Rosenfeld, D.: Aerosol-Cloud Interactions Control of Earth Radiation and Latent Heat Release, Space Science Reviews, Springer, 9p. 6 December 2006, doi:10.1007/s11214-006-9053-6, http://dx.doi.org/10.1007/s11214-006-9053-6, 2006.

Rosenfeld, D. and Woodley, W. L.: Closing the 50-year circle: From cloud seeding to space and back to climate change through precipitation physics. Chapter 6 of "Cloud Systems, Hurricanes, and the Tropical Rainfall Measuring Mission (TRMM)" edited by: Wei-Kuo Tao and Adler, R., 234pp., p. 59–80, Meteorol. Mono. 51, AMS, 2003.

Saleeby, S. M. and Cotton, W. R.: A large-droplet mode and prognostic number concentration of cloud droplets in the Colorado State University Regional Atmospheric Modeling System (RAMS), Part I: Module descriptions and supercell test simulations, J. Appl. Meteorol., 43, 182–195, 2004.

Segal, Y., Khain, A., Pinsky, M., and Rosenfeld, D.: Effects of hygroscopic seeding on raindrop formation as seen from simulations using a 2000-bin spectral cloud parcel model, Atmos. Res., 71, 3–34, 2004.

Simpson, R. H. and Malkus, J. S.: Experiments in hurricane modification, Sci. Amer., 211, 27–37, 1964.

Skamarock, W. C., Klemp, J. B., Dudhia, J., Gill, D. O., Barker, D. M., Wang W., and Powers, J. G.: A description of the Adv. Res., WRF Version 2. NCAR Tech Notes-468+STR, 88 p, 2005.

Thompson, G., Rasmussen, R. M., and Manning, K.: Explicit Forecasts of Winter Precipitation Using an Improved Bulk Microphysics Scheme, Part I: Description and Sensitivity Analysis, Mon. Wea. Rev., 132, 519–542, 2004.

Williams, E., Rosenfeld D., Madden, M., et al.: Contrasting convective regimes over the Amazon: Implications for cloud electrification, J. Geophys. Res., 107(D20), 8082, doi:10.1029/2001JD000380, 2002.

Willoughby, H. E., Jorgensen, D. P., Black, R. A., and Rosenthal, S. L.: Project STORMFURY, A Scientific Chronicle, 1962–1983, Bull. Amer. Meteorol. Soc., 66, 505–514, 1985.

Woodcock, A. H.: Salt nuclei in marine air as a function of altitude and wind force, J. Meteorol., 10, 362–371, 1953.

Van~den~Heever, S. C., Carrió, 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.