Abstract
Using the unprecedented observational capabilities deployed duringthe Cooperative Atmosphere-Surface Exchange Study-99 (CASES-99),we found three distinct turbulence events on the night of 18October 1999, each of which was associated with differentphenomena: a density current, solitary waves, and downwardpropagating waves from a low-level jet. In this study, we focus onthe first event, the density current and its associatedintermittent turbulence. As the cold density current propagatedthrough the CASES-99 site, eddy motions in the upper part of thedensity current led to periodic overturning of the stratifiedflow, local thermal instability and a downward diffusion ofturbulent mixing. Propagation of the density current induced asecondary circulation. The descending motion following the head ofthe density current resulted in strong stratification, a sharpreduction in the turbulence, and a sudden increase in the windspeed. As the wind surge propagated toward the surface, shearinstability generated upward diffusion of turbulent mixing. Wedemonstrate in detail that the height and sequence of the localthermal and shear instabilities associated with the dynamics ofthe density current are responsible for the apparent intermittentturbulence.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Banta, R. M., Newsom, R. K., Lundquist, J. K., Pichugina, Y. L., Coulter, R. L., and Mahrt, L.: 2002, 'Nocturnal Low-Level Jet Characteristics over Kansas during CASES-99', Boundary-Layer Meteorol. 105, 221–252.
Blumen, W., Banta, R., Burns, S. P., Fritts, D. C., Newsom, R., Poulos, G. S., and Sun, J.: 2001, 'Turbulence Statistics of a Kelvin-Helmholtz Billow Event Observed in the Nighttime Boundary Layer during the CASES-99 Field Program', Dyn. Atmos. Oceans 34, 189–204.
Blumen, W., Grossman, R. L., and Piper, M.: 1999, 'Analysis of Heat Budget, Dissipation and Frontogenesis in a Shallow Density Current', Boundary-Layer Meteorol. 91, 281–306.
Burns, S. P. and Sun, J.: 2000, 'Thermocouple Temperature Measurements from the CASES-99 Main Tower', in 14th Symposium on Boundary Layer and Turbulence, 7-11 August 2000, Snowmass, CO, pp. 358-361.
Cheung, T. K. and Little, C. G.: 1990, 'Meteorological Tower, Microbarograph Array, and Sodar Observations of Solitary-LikeWaves in the Nocturnal Boundary Layer', J. Atmos. Sci. 47, 2516–2536.
Coulter, R. L. and Martin, T. J.: 1986, 'Results from a High Power, High Frequency Sodar', Atmos. Res. 20, 257–270.
Doran, J. C. and Horst, T. W.: 1981, 'Velocity and Temperature Oscillations in Drainage Winds', J. Appl. Meteorol. 20, 360–364.
Droegemeier, K. K. and Wilhelmson, R. B.: 1986, 'Kelvin-Helmholtz Instability in a Numerically Simulated Thunderstorm Outflow', Bull. Amer. Meteorol. Soc. 67, 416–417.
Einaudi, F. and Finnigan, J. J.: 1993, 'Wave-Turbulence Dyanmics in the Stably Stratified Boundary Layer', J. Atmos. Sci. 50, 1841–1864.
Einaudi, F., Bedard Jr., A. J., and Finnigan, J. J.: 1989, 'A Climatology of Gravity Waves and Other Coherent Disturbances at the Boulder Atmospheric Observatory during March-April 1984', J. Atmos. Sci. 46, 303–329.
Emanuel, K. A.: 1983, 'On the Dynamical Definitions of “Mesoscale”', in D. K. Lilly and T. Gal-Chen (eds.), Mesoscale Meteorology-Theories, Observations and Models, Reidel, Dordrecht, pp. 1–12.
Etling, D.: 1990, 'On Plume Meandering under Stable Stratification', Atmos. Environ. 24A, 1979–1985.
Finnigan, J. J.: 1988, 'Kinetic Energy Transfer between Internal Gravity Waves and Turbulence', J. Atmos. Sci. 45, 486–505.
Finnigan, J. J., Einaudi, F., and Fua, D.: 1984, 'The Interaction between an Internal GravityWave and Turbulence in the Stably-Stratified Nocturnal Boundary Layer', J. Atmos. Sci. 41, 2409–2436.
Fulton, R., Zrnic, D. S., and Doviak, R. J.: 1990, 'Initiation of a Solitary Wave Family in the Demise of a Nocturnal Thunderstorm Density Current', J. Atmos. Sci. 47, 319–337.
Grund, C. J., Banta, R.M., George, J. L., Howell, J. N., Post, M. J., Richter, R. A., and Weickmann, A. M.: 2001, 'High-Resolution Doppler Lidar for Boundary Layer and Cloud Research', J. Atmos. Oceanic Tech. 18, 376–393.
Howell, J. and Sun, J.: 1999, 'Surface Layer Fluxes in Stable Conditions', Boundary-Layer Meteorol . 90, 495–520.
Ince, T., Pazmany, A. L., Frasier, S. J., and McIntosh, R. E.: 1998, 'A High Resolution FM-CW Sband Radar for Boundary Layer Profiling and Cloud Applications', in Proceedings of the 1998 Battlespace Atmospherics Conference, Hanscom AFB, MA, December 1-3, 1998, pp. 432-439.
Klemp, J. B., Rotunno, R., and Skamarock, W. C.: 1997, 'On the Propagation of Internal Bores', J. Fluid Mech. 331, 81–106.
Lalas, D. P., Einaudi, F., and Fua, D.: 1976, 'The Destabilizing Effect of the Ground on Kelvin-Helmholtz Waves in the Atmosphere', J. Atmos. Sci. 33, 59–69.
Liu, C.-H. and Moncrieff, M. W.: 1996, 'A Numerical Study of the Effects of Ambient Flow and Shear on Density Currents', Mon. Wea. Rev. 124, 2282–2303.
Lu, Nai-Ping, Neff, W. D., and Kaimal, J. C.: 1983, 'Wave and Turbulence Structure in a Disturbed Nocturnal Inversion', Boundary-Layer Meteorol. 26, 141–155.
Mahrt, L.: 1985, 'Vertical Structure and Turbulence in the Very Stable Boundary Layer', J. Atmos. Sci. 42, 2333–2349.
Mahrt, L.: 1999, 'Stratified Atmospheric Boundary Layers', Boundary-Layer Meteorol. 90, 375–396.
Mahrt, L. and Larsen, S.: 1982, 'Small Scale Drainage Front', Tellus 34, 579–587.
Mahrt, L. and Vickers, D.: 2002, 'Contrasting Vertical Structures of Nocturnal Boundary Layers', Boundary-Layer Meteorol. 105, 351–363.
Mahrt, L. Vickers, D., Nakamura, R., Sun, J., Burns, S., Lenschow, D., and Soler, M. R.: 2001, 'Shallow Drainage and Gully Flows', Boundary-Layer Meteorol. 101, 243–260.
Nappo, C. J.: 1991, 'Sporadic Breakdowns of Stability in the PBL over Simple and Complex Terrain', Boundary-Layer Meteorol. 54, 69–87.
Newsom, R. K. and Banta, R. M.: 2002, 'shear Instability Gravity Waves in the Stable Nocturnal Boundary Layer as Observed by Doppler Lidar during CASES-99', J. Atmos. Sci., in press.
Poulos, G. S., Blumen, W., Fritts, D. C., Lundquist, J. K., Sun, J., Burns, S. P., Nappo, C., Banta, R., Newsome, R., Cuxart, J., Terradellas, E., Balsley, B., and Jensen, M.: 2002, 'CASES-99: A Comprehensive Investigation of the Stable Nocturnal Boundary Layer', Bull. Amer. Meteorol. Soc. 83, 555–581.
Simpson, J. E.: 1969, 'A Comparison between Laboratory and Atmospheric Density Currents', Quart. J. Roy. Meteorol. Soc. 95, 758–765.
Simpson, J. E.: 1997, Gravity Currents in the Environment and the Laboratory, Cambridge University Press, 244 pp.
Sun, J., Jensen, N. O., Hummelshoej, P., Jorgensen, H., Mahrt, L., and Chen, Z.: 1998, 'study of Forest-Atmospheric Interactions over a Beech Forest', in 23rd Conference on Agricultural and Forest Meteorology, November 2-6, 1998, Albuquerque, NM, p. 47.
Thorpe, S. A.: 1973, 'Experiments on Instability and Turbulence in a Stratified Shear Flow', J. Fluid Mech. 61, 731–751.
Wulfmeyer, V., Randall, M., Brewer, W. A., and Hardesty, R. M.: 2000, '2 mm Doppler Lidar Transmitter with High Frequency Stability and Low Chirp', Opt. Lett. 25, 1228–1230.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Sun, J., Burns, S.P., Lenschow, D.H. et al. Intermittent Turbulence Associated with a Density Current Passage in the Stable Boundary Layer. Boundary-Layer Meteorology 105, 199–219 (2002). https://doi.org/10.1023/A:1019969131774
Issue Date:
DOI: https://doi.org/10.1023/A:1019969131774