Affiliation:
1. Institut Franco-Allemand de Recherches de Saint-Louis (ISL), Saint-Louis, France
2. Royal Netherlands Meteorological Institute (KNMI), De Bilt, Netherlands
Abstract
Abstract
The propagation of optical and acoustical waves is affected by the atmospheric turbulence through the local instantaneous refractive index structure parameter in a volume of characteristic size r, denoted Cn,r2. Often r is well within the inertial–convective range. In this study, a large-eddy simulation (LES) of spatial resolution Δ is used to analyze the distribution of Cn,Δ2 in the convective boundary layer. The local formulation used to calculate Cn,Δ2 is described and is found to back up the subgrid parameterization of atmospheric LES.
The mean vertical profile behaves according to the mixed layer similarity theory. The spatial organization relates to the presence of buoyant ascending plumes. This structure is associated with some bimodal probability density functions of the inertial–convective range variables, in agreement with experimental results. The standard model of jointly lognormal statistics is challenged. The intermittency of these variables is characterized, and its inertial–convective range component quantitatively agrees with experimental estimates.
The present LES results are used to document the bias produced by averaging the dissipation rates of TKE and temperature variance to estimate the average structure parameters. Comparing with nonconvective turbulence measurements, the bias for CT,r2 is found to depend on the stability. A physical explanation is offered that emphasizes the role of the large-scale turbulence under convective conditions.
Publisher
American Meteorological Society
Reference70 articles.
1. Estimating Cn2 over snow and sea ice from meteorological data.;Andreas;J. Opt. Soc. Amer.,1988
2. Probability distributions for the refractive index structure parameter and the inner scale of turbulence and their implications for flux averaging.;Andreas,2003
3. On the correlation between turbulent velocity and temperature derivatives in the atmospheric surface layer.;Antonia;Bound.-Layer Meteor.,1980
4. Starcasting.;Businger;Bull. Amer. Meteor. Soc.,2002
5. Some aspects of turbulence structure through the depth of the convective boundary layer.;Caughey;Quart. J. Roy. Meteor. Soc.,1979
Cited by
23 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献