• Benjamin, T. B., 1968: Gravity currents and related phenomena. J. Fluid Mech.,31, 209–248.

  • Charba, J., 1974: Application of gravity current model to analysis of squall-line gust front. Mon. Wea. Rev.,102, 140–156.

  • DeMaria, M., and J. D. Pickle, 1988: A simplified system of equations for simulation of tropical cyclones. J. Atmos. Sci.,45, 1542–1554.

  • Doviak, R. J., and R. Ge, 1984: An atmospheric solitary gust observed with a Doppler radar, a tall tower and a surface network. J. Atmos. Sci.,41, 2559–2573.

  • Droegemeier, K. K., and R. B. Wilhelmson, 1987: Numerical simulation of thunderstorm outflow dynamics. Part I: Outflow sensitivity experiments and turbulence dynamics. J. Atmos. Sci.,44, 1180–1210.

  • Frei, C., 1993: Dynamics of a two-dimensional ribbon of shallow water on an f-plane. Tellus,45A, 44–53.

  • Fulton, R., 1990: Initiation of a solitary wave family in the demise of a nocturnal thunderstorm density current. J. Atmos. Sci.,47, 319–337.

  • Gill, A. E., 1982: Atmosphere–Ocean Dynamics. Academic Press, 662 pp.

  • Goff, R. C., 1976: Vertical structure of thunderstorm cutflows. Mon. Wea. Rev.,104, 1429–1440.

  • Haase, S. P., and R. K. Smith, 1989: The numerical simulation of atmospheric gravity currents. Part II: Environments with stable layers. Geophys. Astrophys. Fluid Dyn.,46, 35–51.

  • Haertel, P. T., and R. H. Johnson, 2000: The linear dynamics of squall line mesohighs and wake lows. J. Atmos. Sci.,57, 93–107.

  • Klemp, J. B., R. Rotunno, and W. C. Skamarock, 1994: On the dynamics of gravity currents in a channel. J. Fluid Mech.,269, 169–198.

  • ——, ——, and ——, 1997: On the propagation of internal bores. J. Fluid Mech.,331, 81–106.

  • Koch, S. E., P. B. Dorian, R. Ferrare, S. H. Melfi, W. C. Skillman, and D. Whiteman, 1991: Structure of an internal bore and dissipating gravity current as revealed by Raman lidar. Mon. Wea. Rev.,119, 857–887.

  • Locatelli, J. D., M. T. Stoelinga, P. V. Hobbs, and J. Johnson, 1998:Structure and evolution of an undular bore on the high plains and its effect on migrating birds. Bull. Amer. Meteor. Soc.,79, 1043–1060.

  • May, P. T., 1999: Thermodynamic and vertical velocity structure of two gust fronts observed with wind profiler/RASS during MCTEX. Mon. Wea. Rev.,127, 1796–1807.

  • Mueller, C. K., and R. E. Carbone, 1987: Dynamics of a thunderstorm outflow. J. Atmos. Sci.,44, 1879–1898.

  • Rottman, J. W., and J. E. Simpson, 1989: The formation of internal bores in the atmosphere: A laboratory model. Quart. J. Roy. Meteor. Soc.,115, 941–963.

  • Schär, C., and P. K. Smolarkiewicz, 1996: A synchronous and iterative flux-correction formalism for coupled transport equations. J. Comput. Phys.,128, 101–120.

  • Tao, X., 1994: Wave mean flow interaction and stratospheric sudden warmings in and isentropic model. J. Atmos. Sci.,51, 134–153.

  • Wakimoto, R. M., 1982: The life cycle of thunderstorm gust fronts as viewed with Doppler radar and rawinsonde data. Mon. Wea. Rev.,110, 1060–1082.

All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 219 55 5
PDF Downloads 86 40 2

Some Simple Simulations of Thunderstorm Outflows

Patrick T. HaertelDepartment of Atmospheric Science, Colorado State University, Fort Collins, Colorado

Search for other papers by Patrick T. Haertel in
Current site
Google Scholar
PubMed
Close
,
Richard H. JohnsonDepartment of Atmospheric Science, Colorado State University, Fort Collins, Colorado

Search for other papers by Richard H. Johnson in
Current site
Google Scholar
PubMed
Close
, and
Stefan N. TulichDepartment of Atmospheric Science, Colorado State University, Fort Collins, Colorado

Search for other papers by Stefan N. Tulich in
Current site
Google Scholar
PubMed
Close
Restricted access

Abstract

Three idealized simulations of thunderstorm outflows are presented. Each outflow is a response to an instantaneous low-level cooling. The vertical structures of the coolings differ as do the environments in which the outflows form, and consequently the dynamics of the outflows differ. One outflow is a gravity current, another is a gravity wave, and the third comprises both a gravity current and a gravity wave. The horizontal transport of mass is important for the advance of the gravity-current outflow, but not for the gravity wave outflow, and it is suggested that this is the defining dynamical distinction between the two outflows. The simulations are compared to observations and it is suggested that some outflows previously characterized as gravity currents may better fit the gravity wave or gravity current/wave archetypes. It is also noted that the gravity wave component of an outflow may be generated directly by low-level cooling in addition to the commonly suggested mechanism of the interaction of a gravity current with a stable layer.

Corresponding author address: Dr. Patrick T. Haertel, Department of Atmospheric Science, Colorado State University, Fort Collins, CO 80523-1371.

Email: haertel@atmos.colostate.edu

Abstract

Three idealized simulations of thunderstorm outflows are presented. Each outflow is a response to an instantaneous low-level cooling. The vertical structures of the coolings differ as do the environments in which the outflows form, and consequently the dynamics of the outflows differ. One outflow is a gravity current, another is a gravity wave, and the third comprises both a gravity current and a gravity wave. The horizontal transport of mass is important for the advance of the gravity-current outflow, but not for the gravity wave outflow, and it is suggested that this is the defining dynamical distinction between the two outflows. The simulations are compared to observations and it is suggested that some outflows previously characterized as gravity currents may better fit the gravity wave or gravity current/wave archetypes. It is also noted that the gravity wave component of an outflow may be generated directly by low-level cooling in addition to the commonly suggested mechanism of the interaction of a gravity current with a stable layer.

Corresponding author address: Dr. Patrick T. Haertel, Department of Atmospheric Science, Colorado State University, Fort Collins, CO 80523-1371.

Email: haertel@atmos.colostate.edu

Save