Advances in Science and Research www.adv-sci-res.net 1992-0628 1992-0636 3 8th EMS Annual Meeting and 7th European Conference on Applied Climatology 2008 2009 10.5194/asr-3-17-2009 http://www.adv-sci-res.net/3/17/2009/ http://www.adv-sci-res.net/3/17/2009/asr-3-17-2009.html http://www.adv-sci-res.net/3/17/2009/asr-3-17-2009.pdf 17 21 2009-04-02 Tornado funnel-shaped cloud as convection in a cloudy layer M. V. Zavolgenskiy P. B. Rutkevich Water Problems Institute RAN, South Department, RAN, 198 Stachka av., Rostov-on-Don, Russia Space Research Institute (IKI) RAN, Moscow, Russia Analytical model of convection in a thick horizontal cloud layer with free upper and lower boundaries is constructed. The cloud layer is supposed to be subjected to the Coriolis force due to the cloud rotation, which is a typical condition for tornado formation. It is obtained that convection in such system can look as just one rotating cell in contrast to the usual many-cells Benard convection. The tornado-type vortex is different from spatially periodic convective cells because their amplitudes vanish with distance from the vortex axis. The lower boundary at this convection can substantially move out of the initially horizontal cloud layer forming a single vertical vortex with intense upward and downward flows. The results are also applicable to convection in water layer with negative temperature gradient. Bergeron, T.: The atmosphere and the sea in motion, edited by: Bolin, B., The Rockefeller Institute Press, 440–474, 1959. Browning, K. A. and Ludlam, F. H.: Q. J. Roy. Meteor. Soc., 88, 117–135, 1962. Browning, K. A.: Airflow and Precipitation Trajectories Within Severe Local Storms Which Travel to the Right of the Winds, J. Atmos. Sci., 21, 634–639, 1964. Chandrasekhar, S.: Hydrodynamic and hydromagnetic stability, Oxford, Clarendon Press, 1961. Dowell, D. C., Alexander, C. R., Wurman, J. M., and Wicker, L. J.: Centrifuging of Hydrometeors and Debris in Tornadoes: Radar-Reflectivity Patterns and Wind-Measurement Errors, Mon. Weather Rev., 133, 1501–1524, 2005. Emanuel, K. A. and Bister, M.: Moist Convective Velocity and Buoyancy Scales, J. Atmos. Sci, 53, 3276–3285, 1996. Kessler, E.: Tornadoes: state of knowladge, J. Struct. Div. Proc. Amer. Soc. Civ. Eng., 104, 2, 352–357, 1978. Landau, L. D. and Lifshitz, E. M.: Fluid Mechanics, 2nd Ed., Pergamon Press, 1987. Nalivkin, D. V.: Hurricanes, Storms and Tornadoes, Balkema, Rotterdam, The Netherlands, 1986. Renno, N. O. and Ingersoll, A. P.: J. Atmos. Sci., 53 572–583, 1996. Renno, N. O., Burkett, M. L., and Larkin, M. P.: A Simple Thermodynamical Theory for Dust Devils, J. Atmos. Sci., 55, 3244–3252, 1998. Rutkevich, P. B., Tur, A. V., and Yanovsky, V. V.: Internal wave-surface wave interaction in an arbitrary stratified ocean, Izvestija, Atmos. Ocean. Phys., 25, 794–798, 1989. Souza, E. P., Renno, N. O., and Dias, M. A. F. S.: Convective Circulations Induced by Surface Heterogeneities, J. Atmos. Sci., 57, 2915–2922, 2000. Wicker, L. J. and Wilhelmson, R. B.: Simulation and Analysis of Tornado Development and Decay within a Three-Dimensional Supercell Thunderstorm, J. Atmos. Sci., 52, 2675–2703, 1995.