Generation and Propagation of Inertia–Gravity Waves from Vortex Dipoles and Jets

Shuguang Wang Department of Atmospheric Sciences, Texas A&M University, College Station, Texas

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Fuqing Zhang Department of Meteorology, The Pennsylvania State University, University Park, Pennsylvania

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Chris Snyder National Center for Atmospheric Research, Boulder, Colorado

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Abstract

This study investigates gravity wave generation and propagation from jets within idealized vortex dipoles using a nonhydrostatic mesoscale model. Two types of initially balanced and localized jets induced by vortex dipoles are examined here. These jets have their maximum strength either at the surface or in the middle levels of a uniformly stratified atmosphere. Within these dipoles, inertia–gravity waves with intrinsic frequencies 1–2 times the Coriolis parameter are simulated in the jet exit region. These gravity waves are nearly phase locked with the jets as shown in previous studies, suggesting spontaneous emission of the waves by the localized jets. A ray tracing technique is further employed to investigate the propagation effects of gravity waves. The ray tracing analysis reveals strong variation of wave characteristics along ray paths due to variations (particularly horizontal variations) in the propagating environment.

The dependence of wave amplitude on the jet strength (and thus on the Rossby number of the flow) is examined through experiments in which the two vortices are initially separated by a large distance but subsequently approach each other and form a vortex dipole with an associated amplifying localized jet. The amplitude of the stationary gravity waves in the simulations with 90-km grid spacing increases as the square of the Rossby number (Ro), when Ro falls in a small range of 0.05–0.15, but does so significantly more rapidly when a smaller grid spacing is used.

* Current affiliation: Department of Applied Physics and Applied Mathematics, Columbia University, New York, New York

Corresponding author address: Dr. Fuqing Zhang, Dept. of Meteorology, The Pennsylvania State University, University Park, PA 16802. Email: fzhang@psu.edu

This article included in the Spontaneous Imbalance special collection.

Abstract

This study investigates gravity wave generation and propagation from jets within idealized vortex dipoles using a nonhydrostatic mesoscale model. Two types of initially balanced and localized jets induced by vortex dipoles are examined here. These jets have their maximum strength either at the surface or in the middle levels of a uniformly stratified atmosphere. Within these dipoles, inertia–gravity waves with intrinsic frequencies 1–2 times the Coriolis parameter are simulated in the jet exit region. These gravity waves are nearly phase locked with the jets as shown in previous studies, suggesting spontaneous emission of the waves by the localized jets. A ray tracing technique is further employed to investigate the propagation effects of gravity waves. The ray tracing analysis reveals strong variation of wave characteristics along ray paths due to variations (particularly horizontal variations) in the propagating environment.

The dependence of wave amplitude on the jet strength (and thus on the Rossby number of the flow) is examined through experiments in which the two vortices are initially separated by a large distance but subsequently approach each other and form a vortex dipole with an associated amplifying localized jet. The amplitude of the stationary gravity waves in the simulations with 90-km grid spacing increases as the square of the Rossby number (Ro), when Ro falls in a small range of 0.05–0.15, but does so significantly more rapidly when a smaller grid spacing is used.

* Current affiliation: Department of Applied Physics and Applied Mathematics, Columbia University, New York, New York

Corresponding author address: Dr. Fuqing Zhang, Dept. of Meteorology, The Pennsylvania State University, University Park, PA 16802. Email: fzhang@psu.edu

This article included in the Spontaneous Imbalance special collection.

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  • Badulin, S. I., and V. I. Shrira, 1993: On the irreversibility of internal-wave dynamics due to wave trapping by mean flow inhomogeneities. Part 1. Local analysis. J. Fluid Mech., 251 , 2153.

    • Search Google Scholar
    • Export Citation
  • Bühler, O., and M. E. McIntyre, 2005: Wave capture and wave–vortex duality. J. Fluid Mech., 534 , 6795.

  • Davis, C. A., and K. A. Emanuel, 1991: Potential vorticity diagnosis of cyclogenesis. Mon. Wea. Rev., 119 , 19291953.

  • Dudhia, J., 1993: A nonhydrostatic version of the Penn State NCAR mesoscale model: Validation tests and simulation of an Atlantic cyclone and cold front. Mon. Wea. Rev., 121 , 14931513.

    • Search Google Scholar
    • Export Citation
  • Dunkerton, T. J., and N. Butchart, 1984: Propagation and selective transmission of inertial gravity waves in sudden warming. J. Atmos. Sci., 41 , 14431460.

    • Search Google Scholar
    • Export Citation
  • Eckermann, S. D., and C. J. Marks, 1997: GROGRAT: A new model of the global propagation and dissipation of atmospheric gravity waves. Adv. Space Res., 20 , 12531256.

    • Search Google Scholar
    • Export Citation
  • Flierl, G. R., 1987: Isolated eddy models in geophysics. Annu. Rev. Fluid Mech., 19 , 493530.

  • Ford, R., 1994: Gravity wave radiation from vortex trains in rotating shallow water. J. Fluid Mech., 281 , 81118.

  • Ford, R., M. E. McIntyre, and W. A. Norton, 2000: Balance and the slow quasimanifold: Some explicit results. J. Atmos. Sci., 57 , 12361254.

    • Search Google Scholar
    • Export Citation
  • Fritts, D. C., and M. J. Alexander, 2003: Gravity wave dynamics and effects in the middle atmosphere. Rev. Geophys., 41 , 10031063.

  • Grell, G. A., J. Dudhia, and D. R. Stauffer, 1994: A description of the fifth-generation Penn State/NCAR mesoscale model (MM5). NCAR Tech. Note, NCAR/TN-398+STR, 122 pp.

    • Search Google Scholar
    • Export Citation
  • Hoskins, B. J., M. E. McIntyre, and A. W. Robertson, 1985: On the use and significance of isentropic potential vorticity maps. Quart. J. Roy. Meteor. Soc., 111 , 877946.

    • Search Google Scholar
    • Export Citation
  • Kunze, E., 1985: Near-inertial wave propagation in geostrophic shear. J. Phys. Oceanogr., 15 , 544565.

  • Lighthill, M. J., 1978: Waves in Fluids. Cambridge University Press, 496 pp.

  • Lin, Y., and F. Zhang, 2008: Tracking gravity waves in baroclinic jet-front systems. J. Atmos. Sci., 65 , 24022415.

  • Marks, C. J., and S. D. Eckermann, 1995: A three-dimensional nonhydrostatic ray-tracing model for gravity waves: Formulation and preliminary results for the middle atmosphere. J. Atmos. Sci., 52 , 19591984.

    • Search Google Scholar
    • Export Citation
  • McIntyre, M. E., 2009: Spontaneous imbalance and hybrid vortex–gravity structures. J. Atmos. Sci., 66 , 13151326.

  • Ólafsdóttir, E. I., A. B. Olde Daalhuis, and J. Vanneste, 2008: Inertia–gravity-wave radiation by a sheared vortex. J. Fluid Mech., 596 , 169189.

    • Search Google Scholar
    • Export Citation
  • O’Sullivan, D., and T. J. Dunkerton, 1995: Generation of inertia–gravity waves in a simulated life cycle of baroclinic instability. J. Atmos. Sci., 52 , 36953716.

    • Search Google Scholar
    • Export Citation
  • Plougonven, R., and H. Teitelbaum, 2003: Comparison of a large-scale inertia–gravity wave as seen in the ECMWF analyses and from radiosondes. Geophys. Res. Lett., 30 , 1954. doi:10.1029/2003GL017716.

    • Search Google Scholar
    • Export Citation
  • Plougonven, R., and C. Snyder, 2005: Gravity waves excited by jets: Propagation versus generation. Geophys. Res. Lett., 32 , L18802. doi:10.1029/2005GL023730.

    • Search Google Scholar
    • Export Citation
  • Plougonven, R., and C. Snyder, 2007: Inertia–gravity waves spontaneously generated by jets and fronts. Part I: Different baroclinic life cycles. J. Atmos. Sci., 64 , 25022520.

    • Search Google Scholar
    • Export Citation
  • Plougonven, R., and F. Zhang, 2007: On the forcing of inertia–gravity waves by synoptic-scale flows. J. Atmos. Sci., 64 , 17371742.

  • Plougonven, R., D. J. Muraki, and C. Snyder, 2005: A baroclinic instability that couples balanced motions and gravity waves. J. Atmos. Sci., 62 , 15451559.

    • Search Google Scholar
    • Export Citation
  • Rotunno, R., D. J. Muraki, and C. Snyder, 2000: Unstable baroclinic waves beyond quasigeostrophic theory. J. Atmos. Sci., 57 , 32853295.

    • Search Google Scholar
    • Export Citation
  • Sato, K., 1994: A statistical study of the structure, saturation, and sources of inertio-gravity waves in the lower stratosphere observed with the MU radar. J. Atmos. Terr. Phys., 56 , 755774.

    • Search Google Scholar
    • Export Citation
  • Snyder, C., D. J. Muraki, R. Plougonven, and F. Zhang, 2007: Inertia–gravity waves generated within a dipole vortex. J. Atmos. Sci., 64 , 44174431.

    • Search Google Scholar
    • Export Citation
  • Staquet, C., and J. Sommeria, 2002: Internal gravity waves: From instabilities to turbulence. Annu. Rev. Fluid Mech., 34 , 559593.

  • Uccellini, L. W., and S. E. Koch, 1987: The synoptic setting and possible source mechanisms for mesoscale gravity wave events. Mon. Wea. Rev., 115 , 721729.

    • Search Google Scholar
    • Export Citation
  • Vanneste, J., and I. Yavneh, 2004: Exponentially small inertia–gravity waves and the breakdown of quasigeostrophic balance. J. Atmos. Sci., 61 , 211223.

    • Search Google Scholar
    • Export Citation
  • Viúdez, Á, 2006: Spiral patterns of inertia–gravity waves in geophysical flows. J. Fluid Mech., 562 , 7382.

  • Viúdez, Á, 2007: The origin of the stationary frontal wave packet spontaneously generated in rotating stratified vortex dipoles. J. Fluid Mech., 593 , 359383.

    • Search Google Scholar
    • Export Citation
  • Viúdez, Á, 2008: The stationary frontal wave packet spontaneously generated in mesoscale dipoles. J. Phys. Oceanogr., 38 , 243256.

  • Wang, S., and F. Zhang, 2007: Sensitivity of mesoscale gravity waves to the baroclinicity of jet-front systems. Mon. Wea. Rev., 135 , 670688.

    • Search Google Scholar
    • Export Citation
  • Williams, P. D., T. W. N. Haine, and P. L. Read, 2008: Inertia–gravity waves emitted from balanced flow: Observations, properties, and consequences. J. Atmos. Sci., 65 , 35433556.

    • Search Google Scholar
    • Export Citation
  • Wu, D. L., and F. Zhang, 2004: A study of mesoscale gravity waves over the North Atlantic with satellite observations and a mesoscale model. J. Geophys. Res., 109 , D22104. doi:10.1029/2004JD005090.

    • Search Google Scholar
    • Export Citation
  • Zhang, F., 2004: Generation of mesoscale gravity waves in the upper-tropospheric jet–front systems. J. Atmos. Sci., 61 , 440457.

  • Zhang, F., S. E. Koch, C. A. Davis, and M. L. Kaplan, 2000: A survey of unbalanced flow diagnostics and their application. Adv. Atmos. Sci., 17 , 165183.

    • Search Google Scholar
    • Export Citation
  • Zhang, F., S. E. Koch, C. A. Davis, and M. L. Kaplan, 2001: Wavelet analysis and the governing dynamics of a large-amplitude gravity wave event along the East Coast of the United States. Quart. J. Roy. Meteor. Soc., 127 , 22092245.

    • Search Google Scholar
    • Export Citation
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