Abstract
During the SOFIA experiment, performed in the Azores region in June1992, airborne missions were conducted in the atmospheric boundary layerwith two aircraft instrumented for turbulence measurements. We show howthe conditional sampling technique, applied to the velocity, temperatureand moisture fluctuations, is able to describe the various parcels whichconstitute the turbulent field. Each parcel, so identified, is characterized byits fractional area and by its contribution to the transfers of sensible heat andlatent heat. On the other hand, a scale analysis is conducted by filteringthe turbulent signals in five non-overlapping frequency bands, definedaccording to the characteristic turbulent scales. The contribution of eachband to the turbulent energy and to the transfers is thus presented. Theimportance of the lowest frequencies, which are generally removed fromthe signals by high-pass filtering before computing turbulent fluxes, isshown. In the final section, the conditional sampling technique is applied tothe signals filtered in the various bands. Despite a slight deformation of theeddies due to the filtering technique, the contribution of each parcel can beestimated at the various scales analysed.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Albrecht, B. A., Bretherton, C. S., Johnson, D., Schubert, W. H., and Frish, A. S.: 1995, 'The Atlantic Stratocumulus Transition Experiment-ASTEX', Bull. Amer. Meteorol. Soc. 76, 889–904.
Betts, A. K., Bretherton, C. S., and Klinker, E.: 1995, 'Relation between Mean Boundary-Layer Structure and Cloudiness at the R/V Valdivia during ASTEX', J. Atmos. Sci. 52, 2752–2762.
Caughey, S. J. and Palmer, S. G.: 1979, 'Some Aspects of Turbulence Structure through the Depth of the Convective Boundary Layer', Quart. J. Roy. Meteorol. Soc. 105, 811–827.
Chou, S. H. and Zimmerman, J.: 1989, 'Bivariate Conditional Sampling of Buoyancy Flux during an Intense Cold-Air Outbreak', Boundary-Layer Meteorol. 46, 93–112.
Deardorff, J. W.: 1970, 'Convective Velocity and Temperature Scales for the Unstable Planetary Boundary Layer and for Rayleigh Convection', J. Atmos. Sci. 27, 1211–1215.
Deardorff, J. W.: 1974, 'Three-Dimensional Numerical Study of Turbulence in an Entraining Mixed Layer', Boundary-Layer Meteorol. 7, 199–226.
Druilhet, A., Frangi, J. P., Guedalia, D., and Fontan, J.: 1983, 'Experimental Studies of the Turbulence Structure Parameters of the Convective Boundary Layer', J. Clim. Appl. Meteorol. 22, 593–608.
Frangi, J. P.: 1979, Contribution to the Study of the Principal Turbulence Characteristics of the Planetary Boundary Layer(in French), Ph.D. Thesis, University of Paris VII, France, 129 pp.
Garratt, J. R.: 1992, The Atmospheric Boundary Layer, Cambridge Atmospheric and Space Science Series, Cambridge University Press, 316 pp.
Greenhut, G. K. and Khalsa, S. J. S.: 1982, 'Updraft and Downdraft Events in the Atmospheric Boundary Layer over the Equatorial Ocean', J. Atmos. Sci. 39, 1803–1818.
Kaimal, J. C., Wyngaard, J. C., Haugen, D. A., Coté, O. R., Izumi, Y., Caughey, S. J., and Readings, C. J.: 1976, 'Turbulence Structure in the Convective Boundary Layer', J. Atmos. Sci. 33, 2152–2168.
Kaimal, J. C. and Finnigan, J. J.: 1994, Atmospheric Boundary Layer Flows. Their Structure and Measurement, Oxford University Press, New York, 289 pp.
Khalsa, S. J. S.: 1993, 'Direct Sampling of Entrainment Events in a Marine Stratocumulus Layer', J. Atmos. Sci. 50, 1734–1750.
Lenschow, D. H., Wyngaard, J. C., and Pennel, W. T.: 1980, 'Mean-Field and Second-Moment Budgets in a Baroclinic, Convective Boundary-Layer', J. Atmos. Sci. 37, 1313–1326.
Lenschow, D. H. and Stephens, P. L.: 1980, 'The Role of Thermals in the Convective Boundary Layer', Boundary-Layer Meteorol. 19, 509–532.
Lenschow, D. H. and Stephens, P. L.: 1982, 'Mean Vertical Velocity and Turbulence Intensity Inside and Outside Thermals', Atmos. Environ. 16, 761–764.
Lenschow, D. H. and Stankov, B. B.: 1986, 'Length Scales in the Convective Boundary Layer', J. Atmos. Sci. 43, 1198–1209.
Lenschow, D. H., Mann, J., and Kristensen, L.: 1994, 'How Long is Long Enough when Measuring Fluxes and Other Turbulence Statistics?', J. Atmos. Ocean. Tech. 11, 661–673.
Mann, J. and Lenschow, D. H.: 1994, 'Errors in Airborne Flux Measurements', J. Geophys. Res. 99, 14519–14526.
Mahrt, L. and Paumier, J.: 1984, 'Heat Transport in the Atmospheric Boundary Layer', J. Atmos. Sci. 41, 3061–3075.
Nicholls, S.: 1989, 'The Structure of Radiatively Driven Convection in Stratocumulus', Quart. J. Roy. Meteorol. Soc. 115, 487–511.
Randall, D. A., Shao, Q., and Moeng, C.: 1992, 'A Second-Order Bulk Boundary-Layer Model', J. Appl. Meteorol. 49, 1903–1923.
Réchou, A.: 1995, Turbulence Structure of the Marine Atmospheric Boundary Layer (SOFIA Experiment)(in french), Ph.D. Thesis, University Paul Sabatier, Toulouse, France, 183 pp.
Réchou, A., Durand, P., Druilhet, A., and Bénech, B.: 1995, 'Turbulence Structure of the Boundary Layer Below Marine Clouds in the SOFIA Experiment', Ann. Geophys. 13, 1075–1086.
Shaw, W. J. and Businger, J. A.: 1985, 'Intermittency and the Organization of Turbulence in the Near-Neutral Marine Atmospheric Boundary Layer', J. Atmos. Sci. 28, 918–928.
Weill, A., Klapisz, C., Strauss, B., Baudin, F., Jaupart, C., Van Grunderbeeck, P., and Goutorbe, J. P.: 1980, 'Measuring Heat Flux and Structure Functions of Temperature Fluctuations with an Acoustic Doppler Sodar', J. Appl. Meteorol. 19, 199–205.
Weill, A., Baudin, F., Dupuis, H., Eymard, L., Frangi, J.P., Gérard, E., Durand, P., Bénech, B., Dessens, J., Druilhet, A., Réchou, A., Flamant, P., Seze, G., Pelon, J., Brenguier, J. L., Planton, S., Rolland, J., Leborgne, P., Marsoin, A., Katsaros, K., Queffelou, Y., Tournadre, J., Taylor, P. K., Kent, E., Pascal, R., Schibler, P., Parol, F., Descloitre, J., and Ballois, J. Y.: 1996, 'SOFIA 1992 Experiment during ASTEX', The Global Atmosphere and Ocean System 3, 355–395.
Wyngaard, J. C.: 1983, 'Lectures on the Planetary Boundary Layer', in D. K. Lilly and T. Gal-Chen (eds.), Mesoscale Meteorology-Theories, Observations and Models, pp. 603–650.
Wyngaard, J. C. and Brost, R. A.: 1984, 'Top-Down and Bottom-Up Diffusion of a Scalar in the Convective Boundary Layer', J. Atmos. Sci. 41, 102–112.
Young, G. S.: 1988, 'Turbulence Structure of the Convective Boundary Layer. Part III: TheVertical Velocity Budgets of Thermals and Their Environment', J. Atmos. Sci. 45, 2039–2049.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
RéCHOU, A., DURAND, P. CONDITIONAL SAMPLING AND SCALE ANALYSIS OF THE MARINE ATMOSPHERIC MIXED LAYER -- SOFIA EXPERIMENT. Boundary-Layer Meteorology 82, 81–104 (1997). https://doi.org/10.1023/A:1000113814818
Issue Date:
DOI: https://doi.org/10.1023/A:1000113814818