On a Dynamical Mechanism Underlying the Intensification of Tropical Cyclones

  • N. A. Bakas
  • P. J. Ioannou
Conference paper
Part of the Springer Atmospheric Sciences book series (SPRINGERATMO)


Tropical cyclones are among the most life threatening and destructive natural phenomena on Earth. A dynamical mechanism for cyclone intensification that has been proposed is based on the idea that patches of high vorticity associated with individual convective systems are quickly axisymmetrized, feeding their energy into the circular vortex. In this work, Stochastic Structural Stability Theory (SSST) is used to achieve a comprehensive understanding of this physical mechanism. According to SSST, the distribution of momentum fluxes arising from the field of asymmetric eddies associated with a given mean vortex structure, is obtained using a linear model of stochastic turbulence. The resulting momentum flux distribution is then coupled with the equation governing the evolution of the mean vortex to produce a closed set of eddy/mean vortex equations. We apply the SSST tools to a two dimensional, non-divergent model of stochastically forced asymmetric eddies. We show that the process intensifying a weak vortex is shearing of asymmetric eddies with small azimuthal scale that produces upgradient fluxes. For stochastic forcing with amplitude larger than a certain threshold, these upgradient fluxes lead to a structural instability of the eddy/mean vortex system and to an exponentially growing vortex.


Tropical Cyclone Tropical Cyclone Formation Circular Vortex Vorticity Gradient Vorticity Flux 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.



This research is supported by the IRG-230958 Marie Curie Grant.


  1. Charney JG, Eliasen A (1964) On the growth of hurricane depression. J Atmos Sci 21:68–75CrossRefGoogle Scholar
  2. DelSole T, Farrell BF (1996) The quasi-linear equilibration of a thermally maintained, stochastically excited jet in a quasigeostrophic channel. J Atmos Sci 53:1781–1797. doi:10.1175/1520–0469(1996) 053<1781:TQLEOA>2.0.CO;2CrossRefGoogle Scholar
  3. Farrell BF, Ioannou PJ (1993a) Stochastic dynamics of baroclinic waves. J Atmos Sci 50:4044–4057. doi:10.1175/1520–0469(1993) 050<4044:SDOBW>2.0.CO;2CrossRefGoogle Scholar
  4. Farrell BF, Ioannou PJ (1993b) Stochastic forcing of perturbation variance in unbounded shear and deformation flows. J Atmos Sci 50:200–211. doi:10.1175/1520–0469(1993) 050<0200: SFOPVI>2.0.CO;2CrossRefGoogle Scholar
  5. Farrell BF, Ioannou PJ (2003) Stochastic structural stability of turbulent jets. J Atmos Sci 60:2101–2118. doi:10.1175/1520–0469(2003) 060<2101:SSOTJ>2.0.CO;2CrossRefGoogle Scholar
  6. Montgomery MT, Enagonio J (1998) Tropical cyclogenesis via convectively forced Rossby waves in a three dimensional quasi-geostrophic model. J Atmos Sci 55:3176–3207. doi:10.1175/1520–0469(1998) 055<3176:TCVCFV>2.0.CO;2CrossRefGoogle Scholar
  7. Montgomery MT, Kallenbach RJ (1997) A theory for vortex Rossby waves and its application to spiral bands and intensity changes in hurricanes. Quart J Roy Meteor Soc 123:435–465. doi: 10.1002/qj.49712353810 CrossRefGoogle Scholar
  8. Rotunno R, Emanuel KA (1987) An air-sea interaction theory for tropical cyclones. Part II: evolutionary study using a nonhydrostatic axisymmetric numerical model. J Atmos Sci 44:542–561. doi:10.1175/1520–0469(1987) 044<0542:AAITFT>2.0.CO;2CrossRefGoogle Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2013

Authors and Affiliations

  1. 1.National and Kapodistrian University of AthensAthensGreece

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