气候变化领域集成服务门户(CCPortal): Contributions of internal variability and external forcing to the recent trends in the southeastern pacific and peru-chile upwelling system

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DOI	10.1175/JCLI-D-19-0304.1
	Contributions of internal variability and external forcing to the recent trends in the southeastern pacific and peru-chile upwelling system
	Jebri B.; Khodri M.; Echevin V.; Gastineau G.; Thiria S.; Vialard J.; Lebas N.
发表日期	2020
ISSN	0894-8755
起始页码	10555
结束页码	10578
卷号	33 期号:24
英文摘要	In a warming world context, sea surface temperature (SST) off central-south Peru, northern Chile, and farther offshore increases at a slower rate than the global average since several decades (i.e., cools, relative to the global average). This tendency is synchronous with an interdecadal Pacific oscillation (IPO) negative trend since ;1980, which has a cooling signature in the southeastern Pacific. Here, we use a large ensemble of historical coupled model simulations to investigate the relative roles of internal variability (and in particular the IPO) and external forcing in driving this relative regional cooling, and the associated mechanisms. The ensemble mean reproduces the relative cooling, in response to an externally forced southerly wind anomaly, which strengthens the upwelling off Chile in recent decades. This southerly wind anomaly results from the poleward expansion of the Southern Hemisphere Hadley cell. Attribution experiments reveal that this poleward expansion and the resulting enhanced upwelling mostly occur in response to increasing greenhouse gases and stratospheric ozone depletion since ;1980. An oceanic heat budget confirms that the wind-forced upwelling enhancement dominates the relative cooling near the coast. In contrast, a wind-forced deepening of the mixed layer drives the offshore cooling. While internal variability contributes to the spread of tendencies, the ensemble-mean relative cooling in the southeastern Pacific is consistent with observations and occurs irrespectively of the IPO phase, hence, indicating the preeminent role of external forcing. © 2020 American Meteorological Society.
英文关键词	Expansion; Greenhouse gases; Oceanography; Offshore oil well production; Ozone layer; Surface waters; Associated mechanism; External forcing; Inter-decadal pacific oscillations; Internal variability; Sea surface temperature (SST); Southern Hemisphere; Stratospheric ozone depletion; Upwelling systems; Cooling; cooling; decadal variation; Hadley cell; heat budget; mixed layer; sea surface temperature; Southern Hemisphere; upwelling; wind forcing; Chile; Pacific Ocean; Pacific Ocean (Southeast); Peru
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/171038
作者单位	LOCEAN-IPSL, Sorbonne-Université, CNRS, IRD, UPMC, MNHN, Paris, France
推荐引用方式 GB/T 7714	Jebri B.,Khodri M.,Echevin V.,et al. Contributions of internal variability and external forcing to the recent trends in the southeastern pacific and peru-chile upwelling system[J],2020,33(24).
APA	Jebri B..,Khodri M..,Echevin V..,Gastineau G..,Thiria S..,...&Lebas N..(2020).Contributions of internal variability and external forcing to the recent trends in the southeastern pacific and peru-chile upwelling system.Journal of Climate,33(24).
MLA	Jebri B.,et al."Contributions of internal variability and external forcing to the recent trends in the southeastern pacific and peru-chile upwelling system".Journal of Climate 33.24(2020).