Back to Surface-Atmosphere Interactions or Boundary
Layers & Turbulence
In the atmospheric surface layer, the wavelength of the peak in the vertical
velocity spectrum l_w decreases with increasing stable
stratification and proximity to the surface and this dependence constrains our
ability to perform high-Reynolds number large-eddy simulation (LES). The present
work examines the specific problem of subfilter-scale turbulence modeling in
the surface layer of the atmospheric planetary boundary layer (PBL).
We use the three-dimensional turbulence data collected during the Horizontal Array Turbulence Study (HATS) field program (http://www.atd.ucar.edu/rtf/projects/hats/) to construct SFS fluxes and variances that are modeled in LES codes. A summary of the findings and interpretation of the results are documented in the following articles.
Sullivan, P.P, T.W. Horst, D.H. Lenschow, C-H. Moeng, & J.C. Weil, 2003: Structure of subfilter-scale fluxes in the atmospheric surface layer with application to large-eddy simulation modeling. J. Fluid Mech., 482, 101-139.
Horst, T.W., J. Kleissl, D.H. Lenschow, C. Meneveau, C-H. Moeng, M.B. Parlange, P.P. Sullivan, & J.C. Weil, 2003: HATS: Field observations to obtain spatially-filtered turbulence fields from crosswind arrays of sonic anemometers in the atmospheric surface layer. J. Atmos. Sci., in press.
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Arrays of Sonic Anemometers |
Air-Sea Interaction Tower |
OHATS (http://www.whoi.edu/science/AOPE/dept/OHATS/intro.html) is part of a long term effort to examine air-sea interaction and in particular the coupling of surface layer turbulence in the marine (atmospheric) boundary layer with the underlying surface gravity wave field (water waves). Wind generated waves influence the dynamics of the marine surface layer and the air-sea fluxes of momentum and scalars. Our ability to accurately model the marine surface layer with large-eddy simulation (LES) is however unknown. LES predictions and in particular its subfilter-scale (SFS) parameterization require validation against and guidance from observations for this complex flow. The Ocean Horizontal Array Turbulence Study field campaign is specifically directed at the measurement of SFS variables in the marine surface layer.
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OHATS will be carried out in the summer of 2004 at the recently constructed air-sea interaction tower (ASIT) located off the coast of Martha's Vineyard. (http://www.whoi.edu/science/AOPE/dept/CBLAST/ASIT.html). The ASIT and the Martha's Vineyard Coastal Observatory are operated by Woods Hole Oceanographic Institute. This research project is a collaborative effort between NCAR, Woods Hole Oceanographic Institute, and Pennsylvania State University.
New! OHATS
Website
LES: Large Eddy Simulation
Sean Burns
Janice Coen
Peggy LeMone
Don Lenschow
Chin-Hoh Moeng
Peter
Sullivan
Jielun Sun
Research Highlights
Research Topics Include: Marine stratocumulus regime, Clear-air boundary layers, and Cold-air outbreak convection