气候变化领域集成服务门户(CCPortal): Absolute instabilities in the spatially developing Kuroshio Extension

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DOI	10.1016/j.dynatmoce.2021.101205
	Absolute instabilities in the spatially developing Kuroshio Extension
	Liang X.S.; Hu J.
发表日期	2021
ISSN	03770265
卷号	93
英文摘要	Satellite observations have long revealed to us a spatially growing Kuroshio Extension (KEx), but its underlying dynamics is yet to be studied. With a normal mode model of absolute/convective instability, it is found that the mean zonal jet is unstable at all the sections in the downstream region (east of 154 °E). In each of the resulting complex dispersion relation diagrams there lies a single saddle point associated with a positive temporal growth rate; that is to say, the mean jet is absolutely unstable, implying that KEx favors self-sustained oscillations. By calculation the absolute instability wave has a period increasing from about 27 days to 72 days, and a slightly decreasing wavelength from 360 km to 250 km, as longitude increases from 154 °E to 174 °E, agreeing with those inferred from the wavelet power spectra and Hovmöller diagram of the satellite observations. As KEx travels downstream, the associated eigen-structure of the perturbation velocity changes from a surface trapped mode to a mode with components maximized in the vertical interior. This study shows that at least a portion of the KEx intraseasonal variability is of intrinsic origin, and may be predictable with the absolute/convective instability theory. © 2021 Elsevier B.V.
英文关键词	Absolute instability; Convective instability; Kuroshio Extension
语种	英语
scopus关键词	Oceanography; Absolute instability; Absolute/convective instabilities; Complex dispersion relation; Intraseasonal variability; Satellite observations; Self-sustained oscillations; Underlying dynamics; Wavelet power spectra; Ocean currents; convection; dispersion; jet flow; oceanic current; perturbation; satellite data; spatial analysis; zonal flow; Kuroshio Extension; Pacific Ocean
来源期刊	Dynamics of Atmospheres and Oceans
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/178256
作者单位	State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen, 361102, China; Center for Ocean–Atmosphere Dynamical Studies, Nanjing Institute of Meteorology, Nanjing, 210044, China
推荐引用方式 GB/T 7714	Liang X.S.,Hu J.. Absolute instabilities in the spatially developing Kuroshio Extension[J],2021,93.
APA	Liang X.S.,&Hu J..(2021).Absolute instabilities in the spatially developing Kuroshio Extension.Dynamics of Atmospheres and Oceans,93.
MLA	Liang X.S.,et al."Absolute instabilities in the spatially developing Kuroshio Extension".Dynamics of Atmospheres and Oceans 93(2021).