An experimental study of Reynolds stress and heat flux in the atmospheric surface layer

1971 ◽  
Vol 97 (412) ◽  
pp. 168-180 ◽  
Author(s):  
D. A. Haugen ◽  
J. C. Kaimal ◽  
E. F. Bradley
Keyword(s):  
Experimental Study ◽  
Heat Flux ◽  
Surface Layer ◽  
Reynolds Stress ◽  
Atmospheric Surface Layer

scholarly journals Characteristics of the Heat Flux in the Unstable Atmospheric Surface Layer

2016 ◽  
Vol 73 (11) ◽  
pp. 4519-4529 ◽  
Author(s):  
Maithili Sharan ◽  
Piyush Srivastava
Keyword(s):  
Heat Flux ◽  
Surface Layer ◽  
Temperature Gradient ◽  
Power Law ◽  
Atmospheric Surface Layer ◽  
Potential Temperature ◽  
Stability Parameter ◽  
Layer Potential ◽  
Power Law Function ◽  
The Stability

Abstract The behavior of the heat flux H with respect to the stability parameter (=z/L, where z is the height above the ground, and L is the Obukhov length) in the unstable atmospheric surface layer is analyzed within the framework of Monin–Obukhov similarity (MOS) theory. Using MOS equations, H is expressed as a function of and vertical surface-layer potential temperature gradient . A mathematical analysis is carried out to analyze the theoretical nature of heat flux with the stability parameter by considering the vertical potential temperature gradient as (i) a constant and (ii) a power-law function of heat flux. For a given value of H, two values of associated with different stability regimes are found to occur in both the conditions, suggesting the nonuniqueness of MOS equations. Turbulent data over three different sites—(i) Ranchi, India; (ii) the Met Office’s Cardington, United Kingdom, monitoring facility; and (iii) 1999 Cooperative Atmosphere–Surface Exchange Study (CASES-99; United States—are analyzed to compare the observed nature of H with that predicted by MOS. The analysis of observational data over these three sites reveals that the observed variation of H with is consistent with that obtained theoretically from MOS equations when considering the vertical temperature gradient as a power-law function of heat flux having the exponent larger than 2/3. The existence of two different values of the stability parameter for a given value of heat flux suggests that the application of heat flux as a boundary condition involves some intricacies, and it should be applied with caution in convective conditions.

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.

Daily cycle of the surface layer and energy balance on the high Antarctic Plateau

2005 ◽  
Vol 17 (1) ◽  
pp. 121-133 ◽  
Author(s):  
DIRK VAN AS ◽  
MICHIEL VAN DEN BROEKE ◽  
RODERIK VAN DE WAL
Keyword(s):  
Heat Flux ◽  
Surface Layer ◽  
Energy Balance ◽  
Wind Speed ◽  
Atmospheric Surface Layer ◽  
Specific Humidity ◽  
Inertial Oscillation ◽  
Sensible Heat ◽  
Daily Cycle ◽  
Near Surface

This paper focuses on the daily cycle of the surface energy balance and the atmospheric surface layer during a detailed meteorological experiment performed near Kohnen base in Dronning Maud Land, East Antarctica, in January and February 2002. Temperature, specific humidity, wind speed and the turbulent scales of these quantities, exhibit a strong daily cycle. The sensible heat flux cycle has a mean amplitude of ∼8 W m−2, while the latent heat flux has an amplitude of less than 2 W m−2, which is small compared to the amplitude of net radiation (∼ 35 W m−2) and sub-surface heat (∼ 25 W m−2). Between ∼ 9 and 16 h GMT convection occurs due to a slightly unstable atmospheric surface layer. At the end of the afternoon, the wind speed decreases abruptly and the mixed layer is no longer supported by the sensible heat input; the stratification becomes stable. At night a large near-surface wind shear is measured due to the presence of a nocturnal jet, which is likely to be katabatically driven, but can also be the result of an inertial oscillation. No strong daily cycle in wind direction is recorded, since both the katabatic forcing at night and the daytime forcing by the large-scale pressure gradient were directed approximately downslope during the period of measurement.

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

<p>Polar expedition “Transarctica-2019” 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 “atmosphere – sea ice – ocean upper layer”. 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 “Akademik Treshnikov” to the north of the Archipelagos Franz Josef Land and Svalbard, in the area 80 – 82N, 30 – 45E, in comparison with observations at drifting station “North Pole-35”, worked in the same area in April 2008, and Research station “Ice Base Cape Baranova” in April 2019.</p><p>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.</p><p>Comparison of energy exchange characteristics calculated for the Bolshevik Island (79° N) and area, where expedition “Transarctica 2019” 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.</p><p>Significantly different conditions were observed in the area of the drifting station “North Pole-35”, drifted in April 2008 about 300 km to the north of the “Transarctica 2019” 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 “Transarctica-2019” 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.</p><p>The work supported by the Ministry of Science and Higher Education of the Russian Federation (project no. RFMEFI61619X0108).</p>

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