scholarly journals Monitoring the optical turbulence in the surface layer at Dome C, Antarctica, with sonic anemometers

2015 ◽  
Vol 454 (4) ◽  
pp. 4304-4315 ◽  
Author(s):  
E. Aristidi ◽  
J. Vernin ◽  
E. Fossat ◽  
F.-X. Schmider ◽  
T. Travouillon ◽  
...  
Keyword(s):  
Surface Layer ◽  
Optical Turbulence ◽  
Sonic Anemometers

scholarly journals Influence of the Atmospheric Surface Layer on a Turbulent Flow Downstream of a Ship Superstructure

2013 ◽  
Vol 30 (8) ◽  
pp. 1803-1819 ◽  
Author(s):  
Luksa Luznik ◽  
Cody J. Brownell ◽  
Murray R. Snyder ◽  
Hyung Suk Kang
Keyword(s):  
Surface Layer ◽  
Atmospheric Surface Layer ◽  
The United States ◽  
Naval Academy ◽  
Mean Flow ◽  
Flow Distortion ◽  
Turbulent Statistics ◽  
Sonic Anemometers ◽  
Flight Deck ◽  
Inflow Conditions

Abstract This paper describes a set of turbulence measurements at sea in the area of high flow distortion in the near-wake and recirculation zone behind a ship's superstructure that is similar in geometry to a helicopter hangar/flight deck arrangement found on many modern U.S. Navy ships. The instrumented ship is a 32-m-long training vessel operated by the United States Naval Academy that has been modified by adding a representative flight deck and hangar structure. The flight deck is instrumented with up to seven sonic anemometers/thermometers that are used to obtain simultaneous velocity measurements at various spatial locations on the flight deck, and one sonic anemometer at bow mast is used to characterize inflow atmospheric boundary conditions. Data characterizing wind over the deck at an incoming angle of 0° (head winds) and wind speeds from 2 to 10 m s−1 obtained in the Chesapeake Bay are presented and discussed. Turbulent statistics of inflow conditions are analyzed using the Kaimal universal turbulence spectral model for the atmospheric surface layer and show that for the present dataset this approach eliminates the need to account for platform motion in computing variances and covariances. Conditional sampling of mean flow and turbulence statistics at the flight deck indicate no statistically significant variations between unstable, stable, and neutral atmospheric inflow conditions, and the results agree with the published data for flows over the backward-facing step geometries.

Observations of optical turbulence in the marine atmospheric surface layer during CASPER-West

2018 ◽  
Author(s):  
Benjamin Wauer ◽  
Qing Wang ◽  
Oswaldo Alvarenga ◽  
Ryan Yamaguchi ◽  
John Kalogiros ◽  
...  
Keyword(s):  
Surface Layer ◽  
Atmospheric Surface Layer ◽  
Optical Turbulence

scholarly journals Characterization of Turbulence in the Neutral and Stable Surface Layer at Jang Bogo Station, Antarctica

Atmosphere ◽  
2021 ◽  
Vol 12 (9) ◽  
pp. 1095
Author(s):  
Mauro Mazzola ◽  
Angelo Pietro Viola ◽  
Taejin Choi ◽  
Francesco Tampieri
Keyword(s):  
Surface Layer ◽  
Large Fraction ◽  
Low Frequency ◽  
Systematic Investigation ◽  
Second Order ◽  
Time Interval ◽  
Stable Conditions ◽  
Stable Surface Layer ◽  
Sonic Anemometers ◽  
Submeso Motions

The availability of 5-year time series of velocity and temperature data from two sonic anemometers installed at Jang Bogo Station, Antarctica, allowed a systematic investigation of the turbulence features in a stable layer affected by submeso motions and characterized by the vertical divergence of some second-order moments for a large fraction of time (quite a non-ideal surface layer). The investigation of the effect of the averaging time interval on the statistics of the second-order moments showed that this is greater for the variances of the velocity components with respect to that for the vertical fluxes. This corresponds to a greater contribution from low-frequency motions. The turbulence statistics were investigated and compared with current literature results in terms of vertical structure, share of energy between horizontal and vertical components, skewness of the vertical velocity and turbulent velocities. As a general result, all the normalized second-order moments show a clear change passing from neutral to stable conditions, passing through the range of bulk Richardson number equal to 0.1–1.

scholarly journals The Effect of Filter Dimension on the Subgrid-Scale Stress, Heat Flux, and Tensor Alignments in the Atmospheric Surface Layer

2007 ◽  
Vol 24 (3) ◽  
pp. 360-375 ◽  
Author(s):  
Chad W. Higgins ◽  
Charles Meneveau ◽  
Marc B. Parlange
Keyword(s):  
Heat Flux ◽  
Surface Layer ◽  
Environmental Science ◽  
Field Experiments ◽  
Atmospheric Stability ◽  
Three Dimensional ◽  
Two Dimensional ◽  
Subgrid Scale ◽  
Sonic Anemometers ◽  
Two Dimensional Filtering

Abstract In field experiments designed to study subgrid-scale parameterizations for large eddy simulation, the flow field is often measured and then filtered in two-dimensional planes. This two-dimensional filtering serves as a surrogate for three-dimensional filtering. The question of whether this will yield accurate results in subgrid-scale (SGS) models is addressed by analyzing data from a field experiment in which 16 sonic anemometers were deployed in a four by four grid. The experiment was held in July 2002 at the Surface Layer Turbulence and Environmental Science Test (SLTEST) facility in the Utah West Desert. The full SGS stress tensor and its parameterizations using both two- and three-dimensional filterings are obtained. Comparisons are given between two- and three-dimensional filterings of the field measurements based on probability density functions (PDFs) and energy spectra of the SGS stress elements. The PDFs reveal that quantities calculated with two-dimensional filtering exhibit greater intermittency than those computed with three-dimensional filtering at the same scale. From the spectra it is observed that the different filtering methods result in similar behavior, but that spectra of SGS stress components computed with a three-dimensional filter roll off at a slightly lower wavenumber than those computed with a two-dimensional filter. The PDFs and spectra of the stresses calculated with two- and three-dimensional filters can be made to collapse by reducing the three-dimensional filter scale according to Δ3−D = 0.84Δ2−D. Geometric alignment analyses are performed for the SGS heat flux, SGS stress, and filtered strain rate for the cases of stable, near-neutral, and unstable atmospheric stabilities. Under unstable and near-neutral atmospheric stability, two-dimensional filtering yields acceptable results; however, under stable atmospheric stability, a new approach is recommended and delineated.

Field and laboratory validation of surface layer optical turbulence and off-axis irradiance

2010 ◽  
Author(s):  
Steven T. Fiorino ◽  
John D. Haiducek ◽  
Christopher A. Rice ◽  
Adam D. Downs ◽  
Matthew J. Krizo ◽  
...  
Keyword(s):  
Surface Layer ◽  
Optical Turbulence
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