DOI: 10.1002/2017MS001140
Scopus记录号: 2-s2.0-85042375686
论文题名: Anisotropy of Observed and Simulated Turbulence in Marine Stratocumulus
作者: Pedersen J ; G ; , Ma Y ; -F ; , Grabowski W ; W ; , Malinowski S ; P
刊名: Journal of Advances in Modeling Earth Systems
ISSN: 19422466
出版年: 2018
卷: 10, 期: 2 起始页码: 500
结束页码: 515
语种: 英语
英文关键词: Air entrainment
; Anisotropy
; Aspect ratio
; Boundary layer flow
; Boundary layers
; Climate models
; Clouds
; Free flight
; Large eddy simulation
; Turbulence
; Anisotropic deformation
; Entrainment velocities
; Horizontal grid spacing
; Observations
; Stratocumulus
; Stratocumulus-topped boundary layers
; Sub-grid scale models
; Vertical fluctuations
; Atmospheric thermodynamics
英文摘要: Anisotropy of turbulence near the top of the stratocumulus-topped boundary layer (STBL) is studied using large-eddy simulation (LES) and measurements from the POST and DYCOMS-II field campaigns. Focusing on turbulence ~ m below the cloud top, we see remarkable similarity between daytime and nocturnal flight data covering different inversion strengths and free-tropospheric conditions. With λ denoting wavelength and Zt cloud-top height, we find that turbulence at λ/Zt ≃0.01 is weakly dominated by horizontal fluctuations, while turbulence at λ/Zt002E1 becomes strongly dominated by horizontal fluctuations. Between are scales at which vertical fluctuations dominate. Typical-resolution LES of the STBL (based on POST flight 13 and DYCOMS-II flight 1) captures observed characteristics of below-cloud-top turbulence reasonably well. However, using a fixed vertical grid spacing of 5 m, decreasing the horizontal grid spacing and increasing the subgrid-scale mixing length leads to increased dominance of vertical fluctuations, increased entrainment velocity, and decreased liquid water path. Our analysis supports the notion that entrainment parameterizations (e.g., in climate models) could potentially be improved by accounting more accurately for anisotropic deformation of turbulence in the cloud-top region. While LES has the potential to facilitate improved understanding of anisotropic cloud-top turbulence, sensitivity to grid spacing, grid-box aspect ratio, and subgrid-scale model needs to be addressed. © 2018. The Authors. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/75650
Appears in Collections: 影响、适应和脆弱性 气候变化与战略
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作者单位: Faculty of Physics, Institute of Geophysics, University of Warsaw, Warsaw, Poland; National Center for Atmospheric Research, Boulder, CO, United States
Recommended Citation:
Pedersen J,G,, Ma Y,et al. Anisotropy of Observed and Simulated Turbulence in Marine Stratocumulus[J]. Journal of Advances in Modeling Earth Systems,2018-01-01,10(2)