气候变化领域集成服务门户(CCPortal): Diversity of moderate El Niño events evolution: role of air–sea interactions in the eastern tropical Pacific

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DOI	10.1007/s00382-017-4051-9
	Diversity of moderate El Niño events evolution: role of air–sea interactions in the eastern tropical Pacific
	Dewitte B.; Takahashi K.
发表日期	2019
ISSN	0930-7575
起始页码	7455
结束页码	7476
卷号	52 期号:12
英文摘要	In this paper we investigate the evolution of moderate El Niño events during their developing phase with the objective to understand why some of them did not evolve as extreme events despite favourable conditions for the non-linear amplification of the Bjerknes feedback (i.e. warm SST in Austral winter in the eastern equatorial Pacific). Among the moderate events, two classes are considered consisting in the Eastern Pacific (EP) El Niño events and Central Pacific (CP) events. We first show that the observed SST variability across moderate El Niño events (i.e. inter-event variability) is largest in the far eastern Pacific (east of ~ 130°W) in the Austral winter prior to their peak, which is associated to either significant warm anomaly (moderate EP El Niño) or an anomaly between weak warm and cold (moderate CP El Niño) as reveals by the EOF analysis of the SST anomaly evolution during the development phase of El Niño across the El Niño years. Singular value decomposition (SVD) analysis of SST and wind stress anomalies across the El Niño years further indicates that the inter-event SST variability is associated with an air–sea mode explaining 31% of the covariance between SST and wind stress. The associated SST pattern consists in SST anomalies developing along the coast of Ecuador in Austral fall and expanding westward as far as 130°W in Austral winter. The associated wind stress pattern features westerlies (easterlies) west of ~ 130°W along the equator peaking around June–August for EP (CP) El Niño events. This air–sea mode is interpreted as resulting from a developing seasonal Bjerknes feedback for EP El Niño events since it is shown to be associated to a Kelvin wave response at its peak phase. However equatorial easterlies east of 130°W emerge in September that counters the growing SST anomalies associated to the air–sea mode. These have been particularly active during both the 1972 and the 2015 El Niño events. It is shown that the easterlies are connected to an off-equatorial southerly wind off the coast of Peru and Ecuador. The southerly wind is a response to the coastal SST anomalies off Peru developing from Austral fall. Implications of our results for the understanding of the seasonal ENSO dynamics and diversity are discussed in the light of the analysis of two global climate models simulating realistically ENSO diversity (GFDL_CM2.1 and CESM). © 2017, Springer-Verlag GmbH Germany, part of Springer Nature.
语种	英语
scopus关键词	air-sea interaction; climate feedback; climate modeling; computer simulation; El Nino; numerical model; sea surface temperature; temperature anomaly; westerly; winter; Pacific Ocean; Pacific Ocean (Central); Pacific Ocean (East); Pacific Ocean (Equatorial); Pacific Ocean (Tropical)
来源期刊	Climate Dynamics
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/146278
作者单位	Centro de Estudios Avanzado en Zonas Áridas (CEAZA), Coquimbo, Chile; Departamento de Biología, Facultad de Ciencias del Mar, Universidad Católica del Norte, Coquimbo, Chile; Millennium Nucleus for Ecology and Sustainable Management of Oceanic Islands (ESMOI), Coquimbo, Chile; Laboratoire d’Etudes en Géophysique et Océanographie Spatiales, Toulouse, France; Instituto Geofísico del Perú, Lima, Peru
推荐引用方式 GB/T 7714	Dewitte B.,Takahashi K.. Diversity of moderate El Niño events evolution: role of air–sea interactions in the eastern tropical Pacific[J],2019,52(12).
APA	Dewitte B.,&Takahashi K..(2019).Diversity of moderate El Niño events evolution: role of air–sea interactions in the eastern tropical Pacific.Climate Dynamics,52(12).
MLA	Dewitte B.,et al."Diversity of moderate El Niño events evolution: role of air–sea interactions in the eastern tropical Pacific".Climate Dynamics 52.12(2019).