Midlevel Ventilation’s Constraint on Tropical Cyclone Intensity

Brian Tang Program in Atmospheres, Oceans, and Climate, Massachusetts Institute of Technology, Cambridge, Massachusetts

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Kerry Emanuel Program in Atmospheres, Oceans, and Climate, Massachusetts Institute of Technology, Cambridge, Massachusetts

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Abstract

Midlevel ventilation, or the flux of low-entropy air into the inner core of a tropical cyclone (TC), is a hypothesized mechanism by which environmental vertical wind shear can constrain a tropical cyclone’s intensity. An idealized framework based on steadiness, axisymmetry, and slantwise neutrality is developed to assess how ventilation affects tropical cyclone intensity via two possible pathways: the first through downdrafts outside the eyewall and the second through eddy fluxes directly into the eyewall. For both pathways, ventilation has a detrimental effect on tropical cyclone intensity by decreasing the maximum steady-state intensity significantly below the potential intensity, imposing a minimum intensity below which a TC will unconditionally decay, and providing an upper-ventilation bound beyond which no steady tropical cyclone can exist. Ventilation also decreases the thermodynamic efficiency as the eyewall becomes less buoyant relative to the environment, which compounds the effects of ventilation alone. Finally, the formulation presented in this study is shown to be invariant across a range of thermodynamic environments after a suitable normalization and shows little sensitivity to external parameters.

Corresponding author address: Brian Tang, Massachusetts Institute of Technology, 77 Massachusetts Ave., Rm. 54-1721, Cambridge, MA 02139. Email: btangy@mit.edu

Abstract

Midlevel ventilation, or the flux of low-entropy air into the inner core of a tropical cyclone (TC), is a hypothesized mechanism by which environmental vertical wind shear can constrain a tropical cyclone’s intensity. An idealized framework based on steadiness, axisymmetry, and slantwise neutrality is developed to assess how ventilation affects tropical cyclone intensity via two possible pathways: the first through downdrafts outside the eyewall and the second through eddy fluxes directly into the eyewall. For both pathways, ventilation has a detrimental effect on tropical cyclone intensity by decreasing the maximum steady-state intensity significantly below the potential intensity, imposing a minimum intensity below which a TC will unconditionally decay, and providing an upper-ventilation bound beyond which no steady tropical cyclone can exist. Ventilation also decreases the thermodynamic efficiency as the eyewall becomes less buoyant relative to the environment, which compounds the effects of ventilation alone. Finally, the formulation presented in this study is shown to be invariant across a range of thermodynamic environments after a suitable normalization and shows little sensitivity to external parameters.

Corresponding author address: Brian Tang, Massachusetts Institute of Technology, 77 Massachusetts Ave., Rm. 54-1721, Cambridge, MA 02139. Email: btangy@mit.edu

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  • Bister, M., and K. Emanuel, 1998: Dissipative heating and hurricane intensity. Meteor. Atmos. Phys., 65 , 233240.

  • Black, M., J. Gamache, F. Marks, C. Samsury, and H. Willoughby, 2002: Eastern Pacific Hurricanes Jimena of 1991 and Olivia of 1994: The effect of vertical shear on structure and intensity. Mon. Wea. Rev., 130 , 22912312.

    • Search Google Scholar
    • Export Citation
  • Bryan, G., and R. Rotunno, 2009: Evaluation of an analytical model for the maximum intensity of tropical cyclones. J. Atmos. Sci., 66 , 30423060.

    • Search Google Scholar
    • Export Citation
  • Cram, T., J. Persing, M. Montgomery, and S. Braun, 2007: A Lagrangian trajectory view on transport and mixing processes between the eye, eyewall, and environment using a high-resolution simulation of Hurricane Bonnie (1998). J. Atmos. Sci., 64 , 18351856.

    • Search Google Scholar
    • Export Citation
  • DeMaria, M., 1996: The effect of vertical shear on tropical cyclone intensity change. J. Atmos. Sci., 53 , 20762087.

  • DeMaria, M., and J. Kaplan, 1994: Sea surface temperature and the maximum intensity of Atlantic tropical cyclones. J. Climate, 7 , 13241334.

    • Search Google Scholar
    • Export Citation
  • DeMaria, M., M. Mainelli, L. Shay, J. Knaff, and J. Kaplan, 2005: Further improvements to the Statistical Hurricane Intensity Prediction Scheme (SHIPS). Wea. Forecasting, 20 , 531543.

    • Search Google Scholar
    • Export Citation
  • Emanuel, K., 1986: An air–sea interaction theory for tropical cyclones. Part I: Steady-state maintenance. J. Atmos. Sci., 43 , 585604.

    • Search Google Scholar
    • Export Citation
  • Emanuel, K., 1997: Some aspects of hurricane inner-core dynamics and energetics. J. Atmos. Sci., 54 , 10141026.

  • Emanuel, K., 2000: A statistical analysis of tropical cyclone intensity. Mon. Wea. Rev., 128 , 11391152.

  • Emanuel, K., 2003: Tropical cyclones. Annu. Rev. Earth Planet. Sci., 31 , 75104.

  • Emanuel, K., C. DesAutels, C. Holloway, and R. Korty, 2004: Environmental control of tropical cyclone intensity. J. Atmos. Sci., 61 , 843858.

    • Search Google Scholar
    • Export Citation
  • Emanuel, K., R. Sundararajan, and J. Williams, 2008: Hurricanes and global warming: Results from downscaling IPCC AR4 simulations. Bull. Amer. Meteor. Soc., 89 , 347367.

    • Search Google Scholar
    • Export Citation
  • Frank, W., and E. Ritchie, 2001: Effects of vertical wind shear on the intensity and structure of numerically simulated hurricanes. Mon. Wea. Rev., 129 , 22492269.

    • Search Google Scholar
    • Export Citation
  • Holland, G., 1997: The maximum potential intensity of tropical cyclones. J. Atmos. Sci., 54 , 25192541.

  • Jones, S., 1995: The evolution of vortices in vertical shear. I: Initially barotropic vortices. Quart. J. Roy. Meteor. Soc., 121 , 821851.

    • Search Google Scholar
    • Export Citation
  • Jordan, C., 1958: Mean soundings for the West Indies area. J. Meteor., 15 , 9197.

  • Kalnay, E., and Coauthors, 1996: The NCEP/NCAR 40-Year Reanalysis Project. Bull. Amer. Meteor. Soc., 77 , 437471.

  • Knaff, J., S. Seseske, M. DeMaria, and J. Demuth, 2004: On the influences of vertical wind shear on symmetric tropical cyclone structure derived from AMSU. Mon. Wea. Rev., 132 , 25032510.

    • Search Google Scholar
    • Export Citation
  • Malkus, J., and H. Riehl, 1960: On the dynamics and energy transformations in steady-state hurricanes. Tellus, 12 , 120.

  • Marin, J., D. Raymond, and G. Raga, 2009: Intensification of tropical cyclones in the GFS model. Atmos. Chem. Phys., 9 , 14071417.

  • Nolan, D., and E. Rappin, 2008: Increased sensitivity of tropical cyclogenesis to wind shear in higher SST environments. Geophys. Res. Lett., 35 , L14805. doi:10.1029/2008GL034147.

    • Search Google Scholar
    • Export Citation
  • Powell, M., 1990: Boundary layer structure and dynamics in outer hurricane rainbands. Part II: Downdraft modification and mixed layer recovery. Mon. Wea. Rev., 118 , 918938.

    • Search Google Scholar
    • Export Citation
  • Raymond, D., 1995: Regulation of moist convection over the West Pacific warm pool. J. Atmos. Sci., 52 , 39453959.

  • Reasor, P., M. Montgomery, and L. Grasso, 2004: A new look at the problem of tropical cyclones in vertical shear flow: Vortex resiliency. J. Atmos. Sci., 61 , 322.

    • Search Google Scholar
    • Export Citation
  • Riemer, M., M. Montgomery, and M. Nicholls, 2009: A new paradigm for intensity modification of tropical cyclones: Thermodynamic impact of vertical wind shear on the inflow layer. Atmos. Chem. Phys. Discuss., 9 , 1071110775.

    • Search Google Scholar
    • Export Citation
  • Rotunno, R., Y. Chen, W. Wang, C. Davis, J. Dudhia, and G. Holland, 2009: Large-eddy simulation of an idealized tropical cyclone. Bull. Amer. Meteor. Soc., 90 , 17831788.

    • Search Google Scholar
    • Export Citation
  • Schecter, D., M. Montgomery, and P. Reasor, 2002: A theory for the vertical alignment of a quasigeostrophic vortex. J. Atmos. Sci., 59 , 150168.

    • Search Google Scholar
    • Export Citation
  • Shelton, K., and J. Molinari, 2009: Life of a six-hour hurricane. Mon. Wea. Rev., 137 , 5167.

  • Simpson, R., and R. Riehl, 1958: Mid-tropospheric ventilation as a constraint on hurricane development and maintenance. Preprints, Tech. Conf. on Hurricanes, Miami Beach, FL, Amer. Meteor. Soc., D4-1–D4-10.

    • Search Google Scholar
    • Export Citation
  • Smith, R., W. Ulrich, and G. Sneddon, 2000: On the dynamics of hurricane-like vortices in vertical-shear flows. Quart. J. Roy. Meteor. Soc., 126 , 26532670.

    • Search Google Scholar
    • Export Citation
  • Vecchi, G., and B. Soden, 2007: Increased tropical Atlantic wind shear in model projections of global warming. Geophys. Res. Lett., 34 , L08702. doi:10.1029/2006GL028905.

    • Search Google Scholar
    • Export Citation
  • Wong, M., and J. Chan, 2004: Tropical cyclone intensity in vertical wind shear. J. Atmos. Sci., 61 , 18591876.

  • Wu, L., and S. Braun, 2004: Effects of environmentally induced asymmetries on hurricane intensity: A numerical study. J. Atmos. Sci., 61 , 30653081.

    • Search Google Scholar
    • Export Citation
  • Zeng, Z., Y. Wang, and C. Wu, 2007: Environmental dynamical control of tropical cyclone intensity—An observational study. Mon. Wea. Rev., 135 , 3859.

    • Search Google Scholar
    • Export Citation
  • Zeng, Z., L. Chen, and Y. Wang, 2008: An observational study of environmental dynamical control of tropical cyclone intensity in the Atlantic. Mon. Wea. Rev., 136 , 33073322.

    • Search Google Scholar
    • Export Citation
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