气候变化领域集成服务门户(CCPortal): Role of tropical variability in driving decadal shifts in the Southern Hemisphere summertime eddy-driven jet

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DOI	10.1175/JCLI-D-19-0604.1
	Role of tropical variability in driving decadal shifts in the Southern Hemisphere summertime eddy-driven jet
	Yang D.; Arblaster J.M.; Meehl G.A.; England M.H.; Lim E.-P.; Bates S.; Rosenbloom N.
发表日期	2020
ISSN	0894-8755
起始页码	5445
结束页码	5463
卷号	33 期号:13
英文摘要	The Southern Hemisphere summertime eddy-driven jet and storm tracks have shifted poleward over the recent few decades. In previous studies, explanations have mainly stressed the influence of external forcing in driving this trend. Here we examine the role of internal tropical SST variability in controlling the austral summer jet's poleward migration, with a focus on interdecadal time scales. The role of external forcing and internal variability are isolated by using a hierarchy of Community Earth System Model version 1 (CESM1) simulations, including the pre-industrial control, large ensemble, and pacemaker runs. Model simulations suggest that in the early twenty-first century, both external forcing and internal tropical Pacific SST variability are important in driving a positive southern annular mode (SAM) phase and a poleward migration of the eddy-driven jet. Tropical Pacific SST variability, associated with the negative phase of the interdecadal Pacific oscillation (IPO), acts to shift the jet poleward over the southern Indian and southwestern Pacific Oceans and intensify the jet in the southeastern Pacific basin, while external forcing drives a significant poleward jet shift in the South Atlantic basin. In response to both external forcing and decadal Pacific SST variability, the transient eddy momentum flux convergence belt in the middle latitudes experiences a poleward migration due to the enhanced meridional temperature gradient, leading to a zonally symmetric southward migration of the eddy-driven jet. This mechanism distinguishes the influence of the IPO on the midlatitude circulation from the dynamical impact of ENSO, with the latter mainly promoting the subtropical wave-breaking critical latitude poleward and pushing the midlatitude jet to higher latitudes. © 2020 American Meteorological Society.
英文关键词	Climatology; Tropics; Critical latitude; Earth system model; Eddy momentum flux; Inter-decadal pacific oscillations; Internal variability; Meridional temperature gradient; Southern Annular Mode; Southern Hemisphere; Oceanography; Arctic Oscillation; climate modeling; decadal variation; eddy; jet; Pacific Decadal Oscillation; Rossby wave; sea surface temperature; Southern Hemisphere; summer; teleconnection; Pacific Ocean; Pacific Ocean (Tropical)
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/171255
作者单位	ARC, Centre of Excellence for Climate Extremes, Monash University, Clayton, VIC, Australia; National Center for Atmospheric Research, Boulder, CO, United States; ARC, Centre of Excellence for Climate Extremes, Climate Change Research Centre, University of New South Wales, Sydney, NSW, Australia; Bureau of Meteorology, Melbourne, VIC, Australia
推荐引用方式 GB/T 7714	Yang D.,Arblaster J.M.,Meehl G.A.,et al. Role of tropical variability in driving decadal shifts in the Southern Hemisphere summertime eddy-driven jet[J],2020,33(13).
APA	Yang D..,Arblaster J.M..,Meehl G.A..,England M.H..,Lim E.-P..,...&Rosenbloom N..(2020).Role of tropical variability in driving decadal shifts in the Southern Hemisphere summertime eddy-driven jet.Journal of Climate,33(13).
MLA	Yang D.,et al."Role of tropical variability in driving decadal shifts in the Southern Hemisphere summertime eddy-driven jet".Journal of Climate 33.13(2020).