气候变化领域集成服务门户(CCPortal): Downward Migration of the Zonal-Mean Circulation in the Tropical Atmosphere

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DOI	10.1029/2020GL088084
	Downward Migration of the Zonal-Mean Circulation in the Tropical Atmosphere
	DallaSanta K.; Gerber E.P.
发表日期	2020
ISSN	0094-8276
卷号	47 期号:18
英文摘要	The annular modes of the extratropical atmosphere have received much attention for quantifying variability of the jet streams and storm tracks, despite the fact that the midlatitude circulation itself does not vary uniformly with longitude. While tropical fluctuations in geopotential height have lower amplitude than in the extratropics, they exhibit stronger zonal coherence, or dynamical annularity. A simple index is developed to characterize zonal-mean anomalies of the tropical circulation. It reveals that anomalies in geopotential height and zonal wind migrate downward from the upper troposphere to the surface on a time scale of about 10 days. These features are distinguishable from known modes of tropical variability, the Madden-Julian Oscillation in particular. Evidence from reanalysis and idealized model experiments confirms that this downward migration is quite generic and driven by mechanically forced variations in the strength of the Hadley circulation on subseasonal time scales. ©2020. American Geophysical Union. All Rights Reserved.
英文关键词	Climatology; Extratropical; Geo-potential heights; Hadley circulation; Idealized models; Madden-Julian oscillation; Midlatitudes; Tropical atmospheres; Upper troposphere; Tropics; atmospheric circulation; extratropical environment; geopotential; Hadley cell; jet stream; Madden-Julian oscillation; midlatitude environment; storm track; tropical environment; troposphere; zonal wind
语种	英语
来源期刊	Geophysical Research Letters
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/169695
作者单位	Courant Institute of Mathematical Sciences, New York University, New York, NY, United States; NASA Goddard Institute for Space Studies, New York, NY, United States; Universities Space Research Association, Columbia, MD, United States
推荐引用方式 GB/T 7714	DallaSanta K.,Gerber E.P.. Downward Migration of the Zonal-Mean Circulation in the Tropical Atmosphere[J],2020,47(18).
APA	DallaSanta K.,&Gerber E.P..(2020).Downward Migration of the Zonal-Mean Circulation in the Tropical Atmosphere.Geophysical Research Letters,47(18).
MLA	DallaSanta K.,et al."Downward Migration of the Zonal-Mean Circulation in the Tropical Atmosphere".Geophysical Research Letters 47.18(2020).