Inferring atmospheric surface-layer properties from wind noise in the nocturnal boundary layer

2018 ◽  
Vol 143 (3) ◽  
pp. 1844-1844
Author(s):  
Carl R. Hart ◽  
Gregory W Lyons
Keyword(s):  
Boundary Layer ◽  
Surface Layer ◽  
Atmospheric Surface Layer ◽  
Nocturnal Boundary Layer ◽  
Wind Noise

scholarly journals The Morning NO<sub> x</sub> maximum in the forest atmosphere boundary layer

2011 ◽  
Vol 11 (10) ◽  
pp. 29251-29282 ◽  
Author(s):  
M. Alaghmand ◽  
P. B. Shepson ◽  
T. K. Starn ◽  
B. T. Jobson ◽  
H. W. Wallace ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Surface Layer ◽  
Thermodynamic Stability ◽  
Rural Areas ◽  
Early Morning ◽  
Nocturnal Boundary Layer ◽  
Diurnal Pattern ◽  
Contributing Factors ◽  
Potential Sources ◽  
Soil Emissions

Abstract. During the 1998, 2000, 2001, 2008, and 2009 summer intensives of the Program for Research on Oxidants: PHotochemistry, Emissions and Transport (PROPHET), ambient measurement of nitrogen oxides (NO + NO2 = NOx) were conducted. NO and NOx mole fractions displayed a diurnal pattern with NOx frequently highest in early morning. This pattern has often been observed in other rural areas. In this paper, we discuss the potential sources and contributing factors of the frequently observed morning pulse of NOx. Of the possible potential contributing factors to the observed morning pulse of NO and NOx, we find that surface-layer transport and slow upward mixing from soil emissions, related to the thermodynamic stability in the nocturnal boundary layer (NBL) before its morning breakup are the largest contributors. The morning NOx peak can significantly impact boundary layer chemistry, e.g. through production of HONO on surfaces, and by increasing the importance of NO3 chemistry in the morning boundary layer.

scholarly journals Wind and turbulence profiles in a simulated wind tunnel boundary layer

MAUSAM ◽  
2021 ◽  
Vol 43 (3) ◽  
pp. 283-290
Author(s):  
S. SIVARAMAKRISHNAN
Keyword(s):  
Boundary Layer ◽  
Surface Layer ◽  
Wind Tunnel ◽  
Turbulent Boundary Layer ◽  
Atmospheric Surface Layer ◽  
Length Scale ◽  
Laboratory Modeling ◽  
Tunnel Floor ◽  
Short Test ◽  
Simulated Wind

A system of Honeycomb Flat Plate (HFP) grid and cylindrical rods has been developed to accelerate the growth of a thick (32 cm) turbulent boundary layer, artificially, over rough floor of a low speed short test-section (0.61 m x 0.61 m) wind tunnel. Simulated profiles of wind velocity, longitudinal turbulence intensity and Reynolds stress are shown to have similarity to those of a neutral atmospheric boundary layer over a typical rural terrain. Longitudinal spectrum of turbulence measured at 10,30 and 100 mm above tunnel floor is shown to compare well with atmospheric spectrum and agree closely with the Kolmogoroff's -2/3 law in the inertial sub-range of the spectrum. Based on the length scale of longitudinal turbulence estimated from the spectrum, a scale of 1 :900 has been proposed for laboratory modeling of environmental problems wherein the transport of mass in a neutral atmospheric surface layer IS solely due to eddies of mechanical origin.

Ground effects on pressure fluctuations in the atmospheric boundary layer

1978 ◽  
Vol 86 (3) ◽  
pp. 491-511 ◽  
Author(s):  
M. M. Gibson ◽  
B. E. Launder
Keyword(s):  
Boundary Layer ◽  
Heat Flux ◽  
Surface Layer ◽  
Atmospheric Surface Layer ◽  
Pressure Field ◽  
Pressure Fluctuations ◽  
Gravitational Effects ◽  
Fluctuating Pressure ◽  
Stratified Shear Flow ◽  
Ground Effects

Proposals are made for modelling the pressure-containing correlations which appear in the transport equations for Reynolds stress and heat flux in a simple way which accounts for gravitational effects and the modification of the fluctuating pressure field by the presence of a wall. The predicted changes in structure are shown to agree with Young's (1975) measurements in a free stratified shear flow and with the Kansas data on the atmospheric surface layer.

Arctic atmospheric surface layer in spring during expedition “Transarctica-2019”

2020 ◽  
Author(s):  
Irina Makhotina ◽  
Alexander Makshtas ◽  
Vasilii Kustov
Keyword(s):  
Boundary Layer ◽  
Heat Flux ◽  
Surface Layer ◽  
Sea Ice ◽  
Energy Exchange ◽  
Atmospheric Surface Layer ◽  
Ice Cover ◽  
North Pole ◽  
Surface Formation ◽  
The North

&lt;p&gt;Polar expedition &amp;#8220;Transarctica-2019&amp;#8221; worked in the northern part of the Barents Sea in April 2019. One of the main goals was to study the interaction processes in the system &amp;#8220;atmosphere &amp;#8211; sea ice &amp;#8211; ocean upper layer&amp;#8221;. Complex synchronous observations in atmosphere, snow-ice cover and ocean were performed. Present study describes characteristics of atmospheric surface layer and heat balance of snow-ice cover during drift of RV &amp;#8220;Akademik Treshnikov&amp;#8221; to the north of the Archipelagos Franz Josef Land and Svalbard, in the area 80 &amp;#8211; 82N, 30 &amp;#8211; 45E, in comparison with observations at drifting station &amp;#8220;North Pole-35&amp;#8221;, worked in the same area in April 2008, and Research station &amp;#8220;Ice Base Cape Baranova&amp;#8221; in April 2019.&lt;/p&gt;&lt;p&gt;The characteristics of the near-ice atmospheric layer and energy exchange processes during the drift of the expedition Transarctica-2019 were significantly affected by the presence of clouds and the state of the ice cover. The influence of these factors led to decrease of radiative cooling of the surface, formation of warmer and wetter atmospheric boundary layer and to a weakening of the turbulent exchange between the atmosphere and the snow-ice cover.&lt;/p&gt;&lt;p&gt;Comparison of energy exchange characteristics calculated for the Bolshevik Island (79&amp;#176; N) and area, where expedition &amp;#8220;Transarctica 2019&amp;#8221; worked, showed good agreement between the monthly averaged values and trends in heat fluxes, despite the fact that in the first case the underlying surface was land surface, and in the second - sea ice cover.&lt;/p&gt;&lt;p&gt;Significantly different conditions were observed in the area of the drifting station &amp;#8220;North Pole-35&amp;#8221;, drifted in April 2008 about 300 km to the north of the &amp;#8220;Transarctica 2019&amp;#8221; area. The older and thicker sea ice cover and frequent occurrence of cloudless days, characterized by negative long-wave balance, caused here cooling of the surface, formation of a stable boundary layer, and large values of the sensible heat flux compared to observed during the expedition 2019. Position of &amp;#8220;Transarctica-2019&amp;#8221; to the south of the massifs of old and thick ice, in an area, characterized by medium-thick ice and, as consequence, more intense heat flux through sea ice cover, as well as the presence of leads, determined higher air and surface temperatures and relative humidity.&lt;/p&gt;&lt;p&gt;The work supported by the Ministry of Science and Higher Education of the Russian Federation (project no. RFMEFI61619X0108).&lt;/p&gt;

scholarly journals Interactions within the turbulent boundary layer at high Reynolds number

2011 ◽  
Vol 666 ◽  
pp. 573-604 ◽  
Author(s):  
M. GUALA ◽  
M. METZGER ◽  
B. J. McKEON
Keyword(s):  
Boundary Layer ◽  
Reynolds Number ◽  
Surface Layer ◽  
High Reynolds Number ◽  
Large Scale ◽  
Atmospheric Surface Layer ◽  
Vertical Direction ◽  
Wall Region ◽  
High Reynolds ◽  
Near Wall

Simultaneous streamwise velocity measurements across the vertical direction obtained in the atmospheric surface layer (Reτ ≃ 5 × 105) under near thermally neutral conditions are used to outline and quantify interactions between the scales of turbulence, from the very-large-scale motions to the dissipative scales. Results from conditioned spectra, joint probability density functions and conditional averages show that the signature of very-large-scale oscillations can be found across the whole wall region and that these scales interact with the near-wall turbulence from the energy-containing eddies to the dissipative scales, most strongly in a layer close to the wall, z+ ≲ 103. The scale separation achievable in the atmospheric surface layer appears to be a key difference from the low-Reynolds-number picture, in which structures attached to the wall are known to extend through the full wall-normal extent of the boundary layer. A phenomenological picture of very-large-scale motions coexisting and interacting with structures from the hairpin paradigm is provided here for the high-Reynolds-number case. In particular, it is inferred that the hairpin-packet conceptual model may not be exhaustively representative of the whole wall region, but only of a near-wall layer of z+ = O(103), where scale interactions are mostly confined.

Mean and Peak Wind Loads on Heliostats

1989 ◽  
Vol 111 (2) ◽  
pp. 158-164 ◽  
Author(s):  
J. A. Peterka ◽  
Z. Tan ◽  
J. E. Cermak ◽  
B. Bienkiewicz
Keyword(s):  
Boundary Layer ◽  
Surface Layer ◽  
Wind Tunnel ◽  
Atmospheric Surface Layer ◽  
Ground Level ◽  
Vertical Axis ◽  
Wind Loads ◽  
Preliminary Design ◽  
Turbulence Flow ◽  
The Moment

Mean and peak wind loads on flat rectangular or circular heliostats were measured on models in a boundary layer wind tunnel which included an atmospheric surface layer simulation. Horizontal and vertical forces, moments about horizontal axes at the ground level and at the centerline of the heliostat, and the moment about the vertical axis through the heliostat center were measured. Results showed that loads are higher than predicted from results obtained in a uniform, low-turbulence flow due to the presence of turbulence. Reduced wind loads were demonstrated for heliostats within a field of heliostats and upper bound curves were developed to provide preliminary design coefficients.

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