A sodar study of the temperature structure parameter in the convective boundary layer

1982 ◽  
Vol 22 (3) ◽  
pp. 325-334 ◽  
Author(s):  
G. Dubosclard
Keyword(s):  
Boundary Layer ◽  
Convective Boundary Layer ◽  
Temperature Structure ◽  
Structure Parameter ◽  
Convective Boundary ◽  
Temperature Structure Parameter

Some Statistics of the Temperature Structure Parameter in the Convective Boundary Layer Observed by Sodar

2013 ◽  
Vol 150 (2) ◽  
pp. 215-233 ◽  
Author(s):  
Igor Petenko ◽  
Giangiuseppe Mastrantonio ◽  
Angelo Viola ◽  
Stefania Argentini ◽  
Ilaria Pietroni
Keyword(s):  
Boundary Layer ◽  
Convective Boundary Layer ◽  
Temperature Structure ◽  
Structure Parameter ◽  
Convective Boundary ◽  
Temperature Structure Parameter

scholarly journals Comparison of Direct and Spectral Methods for Evaluation of the Temperature Structure Parameter in Numerically Simulated Convective Boundary Layer Flows

2016 ◽  
Vol 144 (6) ◽  
pp. 2205-2214 ◽  
Author(s):  
Jeremy A. Gibbs ◽  
Evgeni Fedorovich ◽  
Björn Maronga ◽  
Charlotte Wainwright ◽  
Manuel Dröse
Keyword(s):  
Boundary Layer ◽  
Structure Function ◽  
Spectral Method ◽  
Convective Boundary Layer ◽  
Direct Method ◽  
Potential Temperature ◽  
Function Parameter ◽  
Temperature Structure ◽  
Structure Parameter ◽  
Convective Boundary

Abstract In many engineering and meteorological applications, atmospheric turbulence within the planetary boundary layer is described in terms of its representative parameters. One such parameter is the structure-function (or structure) parameter that is used to characterize the intensity of turbulent fluctuations of atmospheric flow variables. Structure parameters are derivatives of structure functions, but are used more frequently than the latter ones for practical needs as they do not explicitly include dependence on the separation distance. The structure parameter of potential temperature, which is the subject of this study, describes the spatial variability of the temperature fluctuations. It is broadly represented in theories and models of electromagnetic and acoustic wave propagation in the atmosphere, and forms the basis for the scintillometer measurement concept. The authors consider three methods to compute the potential temperature structure function and structure parameter: the direct method, the true spectral method, and the conventional spectral method. Each method is tested on high-resolution potential temperature datasets generated from large-eddy simulations of a variety of convective boundary layer flow cases reproduced by two representative numerical codes. Results indicate that the popular conventional spectral method routinely exaggerates the potential temperature structure-function parameter, likely due to the unrealistic assumptions underlying the method. The direct method and true spectral method are recommended as the more suitable approaches.

scholarly journals On the Relationship between the TKE Dissipation Rate and the Temperature Structure Function Parameter in the Convective Boundary Layer

2020 ◽  
Vol 77 (7) ◽  
pp. 2311-2326
Author(s):  
Hubert Luce ◽  
Lakshmi Kantha ◽  
Hiroyuki Hashiguchi ◽  
Abhiram Doddi ◽  
Dale Lawrence ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Structure Function ◽  
Convective Boundary Layer ◽  
Dissipation Rate ◽  
Function Parameter ◽  
Mixing Efficiency ◽  
Buoyancy Frequency ◽  
Temperature Structure ◽  
Convective Boundary

AbstractUnder stably stratified conditions, the dissipation rate ε of turbulence kinetic energy (TKE) is related to the structure function parameter for temperature , through the buoyancy frequency and the so-called mixing efficiency. A similar relationship does not exist for convective turbulence. In this paper, we propose an analytical expression relating ε and in the convective boundary layer (CBL), by taking into account the effects of nonlocal heat transport under convective conditions using the Deardorff countergradient model. Measurements using unmanned aerial vehicles (UAVs) equipped with high-frequency response sensors to measure velocity and temperature fluctuations obtained during the two field campaigns conducted at Shigaraki MU observatory in June 2016 and 2017 are used to test this relationship between ε and in the CBL. The selection of CBL cases for analysis was aided by auxiliary measurements from additional sensors (mainly radars), and these are described. Comparison with earlier results in the literature suggests that the proposed relationship works, if the countergradient term γD in the Deardorff model, which is proportional to the ratio of the variances of potential temperature θ and vertical velocity w, is evaluated from in situ (airplane and UAV) observational data, but fails if evaluated from large-eddy simulation (LES) results. This appears to be caused by the tendency of the variance of θ in the upper part of the CBL and at the bottom of the entrainment zone to be underestimated by LES relative to in situ measurements from UAVs and aircraft. We discuss this anomaly and explore reasons for it.

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