Abstract
This study analyzes eight levels of sonic anemometerdata collected on a 60-m towerduring CASES-99, toward the goal of understanding thevertical structure of thenocturnal boundary layer. Several different regimesare found. Thin boundarylayers are often observed where fluxes decrease with height and approximately vanish between 20 and 30 m aboveground. The flow above the thin boundary layeraccelerates and increasing shear oftengenerates significant turbulence in the middle ofthe night. Thisshear-generated turbulence is often stronger thanthat near the surface corresponding to an upside-downboundary layer. During these conditions,the turbulent transport of turbulence is downwardtoward the surface. The turbulence in this regimeshows features of z-less turbulence to the extentthat neither the height above groundnor the boundary-layer depth are primary scalingvariables. This layer isdifferent from a `residual layer' in thatturbulence is actively generated byshear associated with nocturnal accelerationsand often is stronger than that inthe surface-based boundary layer.
In many cases, the turbulence does not varysignificantly across the towerlayer, implying that the boundary layer ismuch deeper than the 60-m towerlayer. Several case studies are presentedto illustrate the largevariation of vertical structure betweennights.
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References
Beyrich, F.: 1997, 'Mixing Height Estimation from Sodar - A Critical Discussion', Atmos. Environ . 21, 3941–3953.
Blackadar, A. K.: 1957, 'Boundary Layer Wind Maxima and their Significance for the Growth of Nocturnal Inversions', Bull. Amer. Meteorol. Soc. 38, 283–290.
Burns, S. and Sun, J.: 2000, 'Thermocouple Temperature Measurements from the CASES-99 Main Tower', in Fourteenth Symposium on Boundary Layers and Turbulence, American Meteorological Society, pp. 358-361.
Businger, J. A.: 1973, 'Turbulent Transfer in the Atmospheric Surface Layer', in D. H. Haugen (ed.), Workshop on Micrometerology, American Meteorological Society, Boston, MA, pp. 67–100.
Cuxart, J., Morales, G., Terradellas, E., and Yagüe, C.: 2002, 'Study of Coherent Structures and Estimation of the Pressure Transport Terms for the Nocturnal Stable Boundary Layer', Boundary-Layer Meteorol. 105, 305–328.
Cuxart, J. C., Yagüe, G., Morales, E., Terradellas, J., Orbe, J., Calvo, A., Fernndez, M. R., Soler, C., Infante, P., Buenestado, A., Espinalt, H. E., Joergensen, J. M., Rees, J., Vil, J. M., Redondo, I. R. Canangla: 2000, 'Stable Atmospheric Boundary-Layer Experiment in Spain (SABLE 98): A Report', Boundary-Layer Meteorol. 96, 337–370.
Ha, K.-J. and Mahrt, L.: 2001, 'Simple Inclusion of Z-Less Turbulence within and above the Modelled Nocturnal Boundary Layer', Mon. Wea. Rev. 129, 2136–2143.
Högström, U., Smedman A.-S., and Bergström, H.: 1999, 'A Case Study of Two-dimensional Stratified Turbulence', J. Atmos. Sci. 56, 959–976.
Holtslag, A. A. M. and Nieuwstadt, F. T. M.: 1986, 'Scaling the Atmospheric Boundary Layer', Boundary-Layer Meteorol. 36, 201–209.
Lundquist, J.: 2000, The Evening Transition of the Atmospheric Boundary Layer: Inertial Oscillations and Boundary-Layer Dynamics, Ph.D. Thesis, University of Colorado, Boulder, CO, U.S.A.
Mahrt, L.: 1999, 'Stratified Atmospheric Boundary Layers', Boundary-Layer Meteorol. 90, 375–396.
Mahrt, L., Lee, X., Black, A., Neumann, H., and Staebler, R. M.: 2000, 'Vertical Mixing in a Partially Open Canopy', Agric. For. Meteorol. 101, 67–78.
Mahrt, L., Vickers, D., Edson, J., Wilczak, J., Hare, J., and Hojstrup, J.: 2001, 'Vertical Structure of Offshore Flow during RASEX', Boundary-Layer Meteorol. 100, 47–61.
Mahrt, L., Vickers, D., Sun, J., Burns, S., and Lenschow, D.: 2002, 'Shallow Drainage Flows', Boundary-Layer Meteorol. 101, 243–260.
Nappo, C. J.: 1991, 'Sporadic Breakdown of Stability in the PBL over Simple and Complex Terrain', Boundary-Layer Meteorol. 54, 69–87.
Nieuwstadt, F. T. M.: 1984, 'The Turbulent Structure of the Stable, Nocturnal Boundary Layer', J. Atmos. Sci. 41, 2202–2216.
Ohya, Y.: 2001, 'Wind-Tunnel Study of Atmospheric Stable Boundary Layers over a Rough Surface', Boundary-Layer Meteorol. 98, 57–82.
Ostdiek, V. and Blumen, W.: 1997, 'A Dynamic Trio: Inertial Oscillation, Deformation Frontogenesis, and the Ekman-Taylor Boundary Layer', J. Atmos. Sci. 54, 1490–1502.
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.
Smedman, A.-S.: 1988, 'Observations of a Multi-Level Turbulence Structure in a Very Stable Atmospheric Boundary Layer', Boundary-Layer Meteorol. 44, 231–253.
Smedman, A.-S., Bergström, H., and Högström, U.: 1995, 'Spectra, Variances and Length Scales in a Marine Stable Boundary Layer Dominated by a Low Level Jet', Boundary-Layer Meteorol. 76, 211–232.
Smedman, A.-S, Tjernström, H., and Högström, U.: 1993, 'Analysis of the Turbulence Structure of a Marine Low-Level Jet', Boundary-Layer Meteorol. 66, 105–126.
Sorbjan, Z.: 1988, 'Structure of the Stably-Stratified Boundary Layer during the SESAME-1979 Experiment', Boundary-Layer Meteorol. 44, 255–266.
Strang, E. and Fernando, H.: 2001, 'Entrainment and Mixing in Stratified Shear Flows', J. Fluid Mech. 428, 349–386.
Ström, L.: 1999, Effects of Coastal Forcing on Turbulence and Boundary-Layer Structure, Ph.D.Thesis, No. 478, Uppsala University.
Sun, J., Burns, S. P., Lenschow, D. H., Banta, R., Newsom, R., Coulter, R., Frasier, S., Ince, T., Nappo, C., Cuxart, J., Blumen, W., Lee, X., and Hu, X.-Z.: 2002, 'Intermittent Turbulence Associated with a Density Current Passage in the Stable Boundary Layer', Boundary-Layer Meteorol . 105, 199–219.
Tjernström, M. and Rogers, D. P.: 1996, 'Turbulence Structure in Decoupled Marine Stratocumulus: A Case Study from the ASTEX Field Experiment', J. Atmos. Sci. 53, 598–619.
Vickers, D. and Mahrt, L.: 1997, 'Quality Control and Flux Sampling Problems for Tower and Aircraft Data', J. Atmos. Ocean. Tech. 14, 512–526.
Vickers, D., Mahrt, L., Sun, J., and Crawford, T.: 2001, 'Structure of Offshore Flow', Mon. Wea. Rev . 129, 1251–1258.
Wyngaard, J. C.: 1973, 'On Surface-Layer Turbulence', in D. A. Haugen (ed.), Workshop on Micrometeorology, American Meteorological Society, Boston, MA, pp. 101–149.
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Mahrt, L., Vickers, D. Contrasting vertical structures of nocturnal boundary layers. Boundary-Layer Meteorology 105, 351–363 (2002). https://doi.org/10.1023/A:1019964720989
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DOI: https://doi.org/10.1023/A:1019964720989