LES in the Surface Layer: Surface Fluxes, Scaling, and SGS Modeling

Wyngaard, J. C.; Peltier, L. J.; Khanna, Samir

doi:10.1175/1520-0469(1998)055<1733:litsls>2.0.co;2

Cited by 39 publications

(20 citation statements)

References 21 publications

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“…Nowadays, thanks to the increasing power of modern supercomputers, the technique is well known and widely spread within the boundary-layer meteorology community (see the review in Mason, 1994). Numerous studies in boundary-layer research that made use of LES have been published since then, with gradually increasing model resolution over the years (Moeng, 1984;Mason, 1989;Wyngaard et al, 1998;Sullivan et al, 1998;Sorbjan, 2007;, among many others). A detailed intercomparison of different LES codes can be found in Beare et al (2006).…”

Section: Introductionmentioning

confidence: 99%

The Parallelized Large-Eddy Simulation Model (PALM) version 4.0 for atmospheric and oceanic flows: model formulation, recent developments, and future perspectives

et al. 2015

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Abstract. In this paper we present the current version of the Parallelized Large-Eddy Simulation Model (PALM) whose core has been developed at the Institute of Meteorology and Climatology at Leibniz Universität Hannover (Germany). PALM is a Fortran 95-based code with some Fortran 2003 extensions and has been applied for the simulation of a variety of atmospheric and oceanic boundary layers for more than 15 years. PALM is optimized for use on massively parallel computer architectures and was recently ported to general-purpose graphics processing units. In the present paper we give a detailed description of the current version of the model and its features, such as an embedded Lagrangian cloud model and the possibility to use Cartesian topography. Moreover, we discuss recent model developments and future perspectives for LES applications.

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Section: Introductionmentioning

confidence: 99%

The Parallelized Large-Eddy Simulation Model (PALM) version 4.0 for atmospheric and oceanic flows: model formulation, recent developments, and future perspectives

et al. 2015

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“…In the LES, a high-Reynolds number surface drag law based on a "z o " boundary condition is adopted at the lower boundary, essentially a law-of-thewall expression is applied instantaneously at every surface grid point to relate the surface winds and fluxes. Mason and Callen (1986) and Wyngaard et al (1998) discuss the applicability of this approximation, which is experimentally verified in a flat plate boundary layer flow by Nakayama et al (2004). We adapt this law-ofthe-wall parameterization to our wavy-surface application, similar to the methodology used in second-order closure modeling (Gent and Taylor 1976;Li 1995).…”

Section: ͑1b͒mentioning

confidence: 98%

“…We note that SGS modeling is an active research area and numerous alternate approaches to modeling these SGS variables are available (e.g., Meneveau and Katz 2000;Geurts 2001;Sullivan et al 2003;Wyngaard 2004;Sullivan et al 2006a;Hatlee and Wyngaard 2007). LES solutions near flat parameterized z o boundaries are dependent on the SGS closure (e.g., Mason and Thomson 1992;and others).…”

Section: ͑A4͒mentioning

confidence: 99%

Impacts of Ocean Waves on the Atmospheric Surface Layer: Simulations and Observations

Sullivan¹,

McWilliams²

2006

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Standard Form 298 (Rev. 8/98) REPORT DOCUMENTATION PAGEPrescribed by ANSI Std. Z39.18 Form Approved OMB No. 0704-0188The public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing the burden, to Department of Defense, Washington Headquarters Services, Directorate for Information Operations and Reports (0704-0188), 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to any penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. 1. REPORT DATE (DD-MM-YYYY)2. REPORT TYPE 3. DATES COVERED (From -To) 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 5d. PROJECT NUMBER 5e. TASK NUMBER 5f. WORK UNIT NUMBER This this award investigated surface boundary layers and air-sea interaction with theoretical and numerical research. Our long term scientific objective was to explore the nature of intermittency, coherent structures, and turbulent fluxes and their coupling in the surface layers of the marine atmospheric and oceanic planetary boundary layers (PBL). Efforts were focused on the effects of surface gravity waves on the near-surface dynamics, surface fluxes, and coupling between the atmospheric and oceanic PBLs. The final results of this work are provided in 2 journal articles and a reviewed meeting paper. AUTHOR(S) PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) 8. PERFORMING ORGANIZATION REPORT NUMBER SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES) 10. SPONSOR/MONITOR'S ACRONYM(S) SPONSOR/MONITOR'S REPORT NUMBER(S)12Peter Sullivan Abstract. Gravity waves on the sea surface reflect coupling between the atmosphere and ocean. They play important dynamical roles in the transfer of momentum, heat, and scalars, but how they interact with background oceanic (and atmospheric) turbulence is still not well understood. This is especially true under high winds where waves foster Langmuir circulations but also break intermittently.Results from high-resolution large eddy simulations (LESs) that include stochastic breaking waves and the Craik-Leibovich "vortex force" are analyzed. Under certain sea states turbulence (anisotropic seed vorticity) generated by breaking waves initiates Craik-Leibovich instabilities that lead to coherent structures, viz., Langmuir cells and intermittent downwelling jets both of which impact ocean mixing. We suggest a mechanism as to how breaking waves couple with the vortex force that leads to the formation of these flow structures. IntroductionGravity waves at the sea s...

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“…This filter has been used for scale decomposition in many previous studies (e.g. Moeng and Wyngaard 1988;Wyngaard et al 1998;Kimmel et al 2002;Kang 2009). Particularly in our study, given the sinusoidal shape of the surface heat-flux variation and the periodic lateral boundary conditions of large-eddy simulation, the Fourier spectral wave cut-off filter is an appropriate tool to analyze multi-scale features of u at 100 m above ground.…”

Section: Scale Decomposition In Wavenumber Spacementioning

confidence: 99%

Effects of Mesoscale Surface Thermal Heterogeneity on Low-Level Horizontal Wind Speeds

Kang

Lenschow

Sullivan

2012

Boundary-Layer Meteorol

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Using large-eddy simulation, we investigate characteristics of horizontal wind speed at 100 m above the ground, with surface heat-flux variations that are sinusoidal with amplitudes of 0, 50, and 200 W m −2 and wavelengths of 16, 32, and 128 km, and no background flow. When the amplitude is 200 W m −2 , wind speeds induced by the surface-flux variations on scales of 16 and/or 32 km have multiple temporal oscillations from 0600 to 1800 local standard time. The positive peaks first appear before noon. In contrast, for wind speeds induced by the 128-km surface heterogeneity, a single oscillation occurs in the late afternoon, which is much larger than those generated by the 16-and 32-km surface heterogeneity. In addition, at the oscillation onset the kurtosis of the velocity increment over a distance of 1 km significantly increases, which implies intermittency in the generation of 1-km scale eddies. The spatially intermittent energy cascade generated by surface heterogeneity scaled down to 1-km eddies is analogous to the well-known intermittent energy cascade in the inertial subrange. The kurtosis of the 1-km eddies is much larger with the 128-km surface heterogeneity than with the 16-and 32-km heterogeneities. Thus we conclude that localized rapid changes of low-level horizontal wind speed may be caused by significant local surface heterogeneity on scales between a few tens and a few hundreds of kilometres.

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LES in the Surface Layer: Surface Fluxes, Scaling, and SGS Modeling

Cited by 39 publications

References 21 publications

The Parallelized Large-Eddy Simulation Model (PALM) version 4.0 for atmospheric and oceanic flows: model formulation, recent developments, and future perspectives

The Parallelized Large-Eddy Simulation Model (PALM) version 4.0 for atmospheric and oceanic flows: model formulation, recent developments, and future perspectives

Impacts of Ocean Waves on the Atmospheric Surface Layer: Simulations and Observations

Effects of Mesoscale Surface Thermal Heterogeneity on Low-Level Horizontal Wind Speeds

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