气候变化领域集成服务门户(CCPortal): Unified Entrainment and Detrainment Closures for Extended Eddy-Diffusivity Mass-Flux Schemes

CCPortal

DOI	10.1029/2020MS002162
	Unified Entrainment and Detrainment Closures for Extended Eddy-Diffusivity Mass-Flux Schemes
	Cohen Y.; Lopez-Gomez I.; Jaruga A.; He J.; Kaul C.M.; Schneider T.
发表日期	2020
ISSN	19422466
卷号	12 期号:9
英文摘要	We demonstrate that an extended eddy-diffusivity mass-flux (EDMF) scheme can be used as a unified parameterization of subgrid-scale turbulence and convection across a range of dynamical regimes, from dry convective boundary layers, through shallow convection, to deep convection. Central to achieving this unified representation of subgrid-scale motions are entrainment and detrainment closures. We model entrainment and detrainment rates as a combination of turbulent and dynamical processes. Turbulent entrainment/detrainment is represented as downgradient diffusion between plumes and their environment. Dynamical entrainment/detrainment is proportional to a ratio of a relative buoyancy of a plume and a vertical velocity scale, that is modulated by heuristic nondimensional functions which represent their relative magnitudes and the enhanced detrainment due to evaporation from clouds in drier environment. We first evaluate the closures off-line against entrainment and detrainment rates diagnosed from large eddy simulations (LESs) in which tracers are used to identify plumes, their turbulent environment, and mass and tracer exchanges between them. The LES are of canonical test cases of a dry convective boundary layer, shallow convection, and deep convection, thus spanning a broad rangeof regimes. We then compare the LES with the full EDMF scheme, including the new closures, in a single-column model (SCM). The results show good agreement between the SCM and LES in quantities that are key for climate models, including thermodynamic profiles, cloud liquid water profiles, and profiles of higher moments of turbulent statistics. The SCM also captures well the diurnal cycle of convection and the onset of precipitation. ©2020. The Authors.
英文关键词	climate modeling; convective parameterization; deep convection; eddy-diffusivity mass-flux parameterization; entrainment and detrainment; unified parameterization
语种	英语
scopus关键词	Boundary layer flow; Boundary layers; Climate models; Large eddy simulation; Natural convection; Tracers; Turbulent flow; Cloud liquid waters; Downgradient diffusion; Dry convective boundary layer; Single-column model; Thermodynamic profiles; Turbulent entrainment; Turbulent environments; Turbulent statistics; Atmospheric thermodynamics; buoyancy; climate modeling; convection; convective boundary layer; large eddy simulation; parameterization; thermodynamics
来源期刊	Journal of Advances in Modeling Earth Systems
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/156643
作者单位	Department of Environmental Science and Engineering, California Institute of Technology, Pasadena, CA, United States; Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, United States; Pacific Northwest National Laboratory, Richland, WA, United States
推荐引用方式 GB/T 7714	Cohen Y.,Lopez-Gomez I.,Jaruga A.,et al. Unified Entrainment and Detrainment Closures for Extended Eddy-Diffusivity Mass-Flux Schemes[J],2020,12(9).
APA	Cohen Y.,Lopez-Gomez I.,Jaruga A.,He J.,Kaul C.M.,&Schneider T..(2020).Unified Entrainment and Detrainment Closures for Extended Eddy-Diffusivity Mass-Flux Schemes.Journal of Advances in Modeling Earth Systems,12(9).
MLA	Cohen Y.,et al."Unified Entrainment and Detrainment Closures for Extended Eddy-Diffusivity Mass-Flux Schemes".Journal of Advances in Modeling Earth Systems 12.9(2020).