气候变化领域集成服务门户(CCPortal): Revealing the Dynamical Transition of Anisotropy Behind the HOST by Koopman Analysis

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DOI	10.1029/2020GL091123
	Revealing the Dynamical Transition of Anisotropy Behind the HOST by Koopman Analysis
	Li L.; Zuo H.; Chen B.; Guo Y.; Ma M.; Dong L.
发表日期	2020
ISSN	0094-8276
卷号	47 期号:23
英文摘要	The hockey-stick transition (HOST), which is depicted by the “local and global shear” assumption, about the turbulence kinetic energy with the averaged flow intensity is noticed widely. However, the intrinsic mechanism of averaged flow influences turbulence kinetic energy via shear and buoyancy is missing. In this research, we deploy the Koopman operator to expose invariant subspaces of the Ri series to identify the quasiperiodic coherent structures from the single tower observation. Analysis of turbulence fluxes and anisotropy demonstrates the mechanism, that is, horizontal kinetic energy coupled with vertical downward flux, whereby anisotropy evolution is changed. Examining the anisotropy invariants changing with kinetic energy reveals a dynamical transition that determines the threshold of HOST. Moreover, the mechanism about how the shear and vertical momentum influences the transition point of HOST is at first given by a group of a quadratic relationship when the anisotropy crossed over the transition point. ©2020. The Authors.
英文关键词	Anisotropy; Kinetic energy; Shear flow; Transition flow; Turbulence; Coherent structure; Dynamical transition; Intrinsic mechanisms; Invariant subspace; Quasi-periodic; Transition point; Turbulence fluxes; Turbulence kinetic energy; Kinetics; atmospheric dynamics; buoyancy; energy balance; kinetic energy; momentum; shear flow; turbulence; wind velocity
语种	英语
来源期刊	Geophysical Research Letters
来源机构	中国科学院西北生态环境资源研究院
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/169337
作者单位	Key Laboratory for Semi-Arid Climate Change of the Ministry of Education, College of Atmospheric Science, Lanzhou University, Lanzhou, China; Tianjin Meteorological Information Center, Tianjin, China; Key Laboratory for Land Process and Climate Change in Cold and Arid Regions, Northwest Institute of Eco-Environment and Resources, Chinese Academy Sciences, Lanzhou, China
推荐引用方式 GB/T 7714	Li L.,Zuo H.,Chen B.,et al. Revealing the Dynamical Transition of Anisotropy Behind the HOST by Koopman Analysis[J]. 中国科学院西北生态环境资源研究院,2020,47(23).
APA	Li L.,Zuo H.,Chen B.,Guo Y.,Ma M.,&Dong L..(2020).Revealing the Dynamical Transition of Anisotropy Behind the HOST by Koopman Analysis.Geophysical Research Letters,47(23).
MLA	Li L.,et al."Revealing the Dynamical Transition of Anisotropy Behind the HOST by Koopman Analysis".Geophysical Research Letters 47.23(2020).