气候变化领域集成服务门户(CCPortal): Separating freshwater flux effects on ENSO in a hybrid coupled model of the tropical Pacific

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DOI	10.1007/s00382-020-05245-y
	Separating freshwater flux effects on ENSO in a hybrid coupled model of the tropical Pacific
	Gao C.; Zhang R.-H.; Karnauskas K.B.; Zhang L.; Tian F.
发表日期	2020
ISSN	0930-7575
起始页码	4605
结束页码	4626
卷号	54
英文摘要	Freshwater flux (FWF) at the sea surface, defined as precipitation minus evaporation, is a major atmospheric forcing to the ocean that affects sea surface salinity (SSS) and buoyancy flux (QB). Physically, there exist two pathways through which interannual FWF variability can affect the ocean: one through SSS and the other through QB. The roles of the interannual FWF variability in modulating the El Niño-Southern Oscillation (ENSO) through its effects on SSS or QB are separately examined using a hybrid coupled model (HCM) of the tropical Pacific; its ocean component is a layer model in which the topmost layer (the first layer) is treated as a mixed layer (ML) whose depth (Hm) is explicitly predicted using an embedded bulk ML model with Hm being directly affected by QB, whereas in level ocean models, QB does not have a direct and explicit effect on Hm. Four experiments are conducted using the HCM that is designed to illustrate the effects of these processes on coupled simulations systematically. It is demonstrated that interannual FWF variability serves as a positive feedback on ENSO through its collective effects on both SSS and QB. Individually, the interannual FWF effect through SSS accounts for about 80% in terms of ENSO amplitude in the Niño 3.4 area, while that through buoyancy flux accounts for about 26%. This indicates that ocean models without explicitly taking into account the direct FWF effect on QB (typically in level ocean models) could underestimate the positive feedback on ENSO compared with layer ocean models in which the FWF effects are collectively represented on both SSS and QB. Further implications for model biases associated with FWF effects are discussed. © 2020, Springer-Verlag GmbH Germany, part of Springer Nature.
英文关键词	Buoyancy flux; Feedbacks on ENSO; Freshwater flux effects; Layer and level ocean models; Sea surface salinity
语种	英语
scopus关键词	annual variation; atmospheric forcing; buoyancy; El Nino-Southern Oscillation; freshwater; mixed layer; modeling; sea surface salinity; Pacific Ocean; 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/145460
作者单位	CAS Key Laboratory of Ocean Circulation and Waves, Institute of Oceanology, and Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, 266071, China; Pilot National Laboratory for Marine Science and Technology, Qingdao, 266237, China; University of Chinese Academy of Sciences, Beijing, 10029, China; Department of Atmospheric and Oceanic Sciences, University of Colorado, Boulder, CO, United States; Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, United States
推荐引用方式 GB/T 7714	Gao C.,Zhang R.-H.,Karnauskas K.B.,et al. Separating freshwater flux effects on ENSO in a hybrid coupled model of the tropical Pacific[J],2020,54.
APA	Gao C.,Zhang R.-H.,Karnauskas K.B.,Zhang L.,&Tian F..(2020).Separating freshwater flux effects on ENSO in a hybrid coupled model of the tropical Pacific.Climate Dynamics,54.
MLA	Gao C.,et al."Separating freshwater flux effects on ENSO in a hybrid coupled model of the tropical Pacific".Climate Dynamics 54(2020).