Abstract
Occurrences of intermittent turbulence in very stable conditions during theCASES-99 field study near Leon, Kansas were detected at several sites separatedby horizontal distances from 1 km to 25 km using sonic anemometers, minisodarsand a laser scintillometer. Periods with significant turbulent heat fluxes wereseparated by extended quiescent periods with little or no flux, and most of theflux during a night was realized in relatively small fractions (<20%) of thetotal time. There appeared to be no relationship between this intermittencyfraction and the median z/L (z being height and L the Obukhov length)value for the night, although overall sensible heat flux values on very stablenights were significantly less than those on less stable nights. The intermittencyfraction at 7 m was found to increase with mean wind speed at 20 m and, to alesser extent, with wind shear between 20 m and 30 m. While correspondenceof turbulent episodes at two sites separated by 1 km was common, it was less common at separations on the order of 20 km. There were time periods, however, during which enhanced turbulence levels were seen nearly simultaneously at large separation distances. Turbulence episodes were found to propagate upward or downward at different times with no readily defined large-scale controlling mechanism.
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Coulter, R. L.: 1990, 'A Case Study of Turbulence in the Stable Nocturnal Boundary Layer', Boundary-Layer Meteorol.52, 75–91.
Coulter, R. L. and Doran, J. C.: 2000, 'Intermittent Turbulence Events Observed with a Sonic Anemometer and Minisodar during CASES99', in preprint, 14th Symposium on Boundary Layer and Turbulence, Aspen, CO, 7-11 August 2000, American Meteorological Society, Boston, MA, pp. 622–625.
Coulter, R. L. and Martin, T. J., 1986, 'Results from a High Power, High Frequency Sodar', Atmos. Res. 20, 257–270.
Coulter, R. L. and Wesely, M. L.: 1980, 'Estimates of Surface Heat Flux from Sodar and Laser Scintillation Measurements in the Unstable Boundary Layer', J. Appl. Meteorol. 19, 1209–1222.
Coulter, R. L., Klazura, G., Lesht, B. M., Martin, T. J., Shannon, J. D., Sisterson, D. L., and Wesely, M. L.: 1999, 'The Argonne Boundary Layer Experiments Facility: Using Minisodars to Complement a Wind Profiler Network', Meteorol. Atmos. Phys. 71, 53–59.
Howell, J. F. and Sun, J.: 1999, 'Surface-Layer Fluxes in Stable Conditions', Boundary-Layer Meteorol. 90, 495-520.
McMillen, R. T.: 1988, 'An Eddy Correlation Technique with Extended Applicability to Non-Simple Terrain', Boundary-Layer Meteorol. 43, 231–245.
Neff, W. D. and Coulter, R. L.: 1986, 'Acoustic Remote Sensing', in Probing the Atmospheric Boundary Layer, American Meteorological Society, Boston, MA, pp. 201–235.
Poulos, G. S., Blumen, W., Fritts, D. C., Lundquist, J. K., Sun, J., Burns, S. P., Nappo, C., Banta, R., Newsom, 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.
Sun, J., Burns, S., and Lenschow, D.: 2000, 'Turbulence Intermittency in the Stable Boundary Layer', in preprints, 14th Symposium on Boundary Layers and Turbulence, 7-11 August 2000, Aspen, CO, American Meteorological Society, Boston, MA, pp. 329–331.
Weijers, E. P., van Delden, A., Vugts, H. F., and Meesters, A. G. C. A.:1995, 'The Composite Horizontal Wind Field within Convective Structures of the Atmospheric Surface Layer', J. Atmos. Sci. 52, 3866–3878.
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Coulter, R.L., Doran, J.C. Spatial and Temporal Occurrences of Intermittent Turbulence During CASES-99. Boundary-Layer Meteorology 105, 329–349 (2002). https://doi.org/10.1023/A:1019993703820
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DOI: https://doi.org/10.1023/A:1019993703820