Grey-Zone Turbulence in the Neutral Atmospheric Boundary Layer - Météo-France Accéder directement au contenu
Article Dans Une Revue Boundary-Layer Meteorology Année : 2019

Grey-Zone Turbulence in the Neutral Atmospheric Boundary Layer

Résumé

The turbulence generated by wind shear is described at grey-zone resolutions using a theoretical neutral boundary layer based on atmospheric conditions constructed from measurements from the CASES-99 field campaign. Six-metre-resolution large-eddy simulations (LES) are performed to access the "true" resolved turbulence for two cases, corresponding to a forcing of the boundary layer by zonal geostrophic wind speeds of 10 m s −1 and 20 m s −1. The LES fields are subject to a coarse-graining procedure in order to compute turbulence diagnostics in the grey zone, with the robustness and weakness of various averaging procedures tested, for which simple top-hat averaging is found to be both suitable and accurate. In addition, the "true" resolved and subgrid-scale fluxes, variances, turbulent kinetic energy and production terms are quantified on various scales. The grey zone of turbulence is defined as the range of scales where 10-90% of turbulence is resolved, which here ranges from resolutions of 25-800 m (0.03 < x/h < 1, where x is the horizontal resolution, and h is the boundarylayer height). The subgrid/resolved partitioning of the variances of the velocity components depends on the geostrophic wind speed, which is not the case for the momentum-flux partitioning. Dynamic production terms show that fine-scale turbulence is isotropic (x/h < 0.03) and is quasi one-directional, oriented in the direction of the geostrophic wind vector at the mesoscale (x/h > 1). The turbulence parametrizations, which are tested in the Méso-NH model by running simulations at resolutions from the LES scale to the mesoscale, fail to produce the correct turbulence regardless of resolution.
Fichier principal
Vignette du fichier
Honnert2019_Article_Grey-ZoneTurbulenceInTheNeutra.pdf (2.25 Mo) Télécharger le fichier
Origine : Fichiers éditeurs autorisés sur une archive ouverte

Dates et versions

meteo-03357818 , version 1 (29-09-2021)

Identifiants

Citer

Rachel Honnert. Grey-Zone Turbulence in the Neutral Atmospheric Boundary Layer. Boundary-Layer Meteorology, 2019, 170 (2), pp.191-204. ⟨10.1007/s10546-018-0394-y⟩. ⟨meteo-03357818⟩
25 Consultations
59 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More