气候变化领域集成服务门户(CCPortal): Interaction of the westerlies with the Tibetan Plateau in determining the Mei-Yu termination

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DOI	10.1175/JCLI-D-19-0319.1
	Interaction of the westerlies with the Tibetan Plateau in determining the Mei-Yu termination
	Kong W.; Chiang J.C.H.
发表日期	2020
ISSN	0894-8755
起始页码	339
结束页码	363
卷号	33 期号:1
英文摘要	This study explores how the termination of the mei-yu is dynamically linked to the westerlies impinging on the Tibetan Plateau. It is found that the mei-yu stage terminates when the maximum upper-tropospheric westerlies shift beyond the northern edge of the plateau, around 408N. This termination is accompanied by the disappearance of tropospheric northerlies over northeastern China. The link between the transit of the jet axis across the northern edge of the plateau, the disappearance of northerlies, and termination of the mei-yu holds on a range of time scales from interannual through seasonal and pentad. Diagnostic analysis indicates that the weakening of the meridional moisture contrast and meridional wind convergence, mainly resulting from the disappearance of northerlies, causes the demise of the mei-yu front. The authors propose that the westerlies migrating north of the plateau and consequent weakening of the extratropical northerlies triggers the mei-yu termination. Model simulations are employed to test the causality between the jet and the orographic downstream northerlies by repositioning the northern edge of the plateau. As the plateau edge extends northward, orographic forcing on the westerlies strengthens, leading to persistent strong downstream northerlies and a prolonged mei-yu. Idealized simulations with a dry dynamical core further demonstrate the dynamical link between the weakening of orographically forced downstream northerlies with the positioning of the jet from south to north of the plateau. Changes in the magnitude of orographically forced stationary waves are proposed to explain why the downstream northerlies disappear when the jet axis migrates beyond the northern edge of the plateau. © 2019 American Meteorological Society. For information regarding reuse of this content and general copyright information, consult the AMS Copyright Policy (www.ametsoc.org/PUBSReuseLicenses).
英文关键词	Climate models; Climatology; Diagnostic analysis; Dynamical core; Meridional winds; Model simulation; Orographic forcing; South-to-North; Stationary waves; Tibetan Plateau; Troposphere; annual variation; atmospheric moisture; jet stream; meridional circulation; seasonal variation; troposphere; westerly; wind; China; Qinghai-Xizang Plateau; Citrus maxima
语种	英语
来源期刊	Journal of Climate
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/171558
作者单位	Department of Geography, Berkeley Atmospheric Sciences Center, University of California, Berkeley, Berkeley, CA, United States
推荐引用方式 GB/T 7714	Kong W.,Chiang J.C.H.. Interaction of the westerlies with the Tibetan Plateau in determining the Mei-Yu termination[J],2020,33(1).
APA	Kong W.,&Chiang J.C.H..(2020).Interaction of the westerlies with the Tibetan Plateau in determining the Mei-Yu termination.Journal of Climate,33(1).
MLA	Kong W.,et al."Interaction of the westerlies with the Tibetan Plateau in determining the Mei-Yu termination".Journal of Climate 33.1(2020).