气候变化领域集成服务门户(CCPortal): Diagnosing Subgrid Mesoscale Eddy Fluxes With and Without Topography

CCPortal

DOI	10.1029/2019MS001721
	Diagnosing Subgrid Mesoscale Eddy Fluxes With and Without Topography
	Khani S.; Jansen M.F.; Adcroft A.
发表日期	2019
ISSN	19422466
起始页码	3995
结束页码	4015
卷号	11 期号:12
英文摘要	General circulation models use subgrid-scale (SGS) parameterizations to represent the effects of unresolved mesoscale eddies on large-scale motions. Most of the current SGS parameterizations are based on a theoretical understanding of transient eddies, where the mean flow is a temporal average. In this work, we use a spatial filtering analysis to better understand the scale-dependent characteristics of the SGS fluxes. Specifically, we apply the filtering approach to diagnose SGS eddy volume fluxes and eddy velocity scales in a hierarchy of model configurations from a flat bottom channel to an idealized Southern Hemisphere. Importantly, SGS volume fluxes include significant contributions from standing meanders; unlike for transient eddies, the vertically integrated SGS volume flux does not necessarily integrate to 0. To accommodate net vertically integrated eddy fluxes, we define a SGS eddy diffusivity based on planetary potential vorticity (PV) diffusion. We diagnose the transient and standing contributions to SGS fluxes and associated effective diffusivities. In the presence of bottom topography or continental barriers the standing component of the PV diffusivity becomes dominant at large filter scales in the westerly wind region, while the transient component remains dominant in the easterly wind region. Our results suggest that the diagnosed PV diffusivity can be parameterized using mixing length theory based on a priori estimates of SGS velocity and length scales. ©2019. The Authors.
语种	英语
scopus关键词	Diffusion; Parameterization; Dependent characteristics; Effective diffusivities; General circulation model; Mixing length theories; Model configuration; Potential vorticity; Southern Hemisphere; Transient components; Topography; bottom topography; detection method; diffusivity; flux measurement; general circulation model; mesoscale eddy; mesoscale motion; parameterization; potential vorticity; topography; westerly
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/156808
作者单位	Program in Atmospheric and Oceanic Sciences, Princeton University, Princeton, NJ, United States; Applied Physics Laboratory and School of Oceanography, University of Washington, Seattle, WA, United States; Department of Geophysical Sciences, University of Chicago, Chicago, IL, United States; NOAA Geophysical Fluid Dynamics Laboratory, PrincetonNJ, United States
推荐引用方式 GB/T 7714	Khani S.,Jansen M.F.,Adcroft A.. Diagnosing Subgrid Mesoscale Eddy Fluxes With and Without Topography[J],2019,11(12).
APA	Khani S.,Jansen M.F.,&Adcroft A..(2019).Diagnosing Subgrid Mesoscale Eddy Fluxes With and Without Topography.Journal of Advances in Modeling Earth Systems,11(12).
MLA	Khani S.,et al."Diagnosing Subgrid Mesoscale Eddy Fluxes With and Without Topography".Journal of Advances in Modeling Earth Systems 11.12(2019).