气候变化领域集成服务门户(CCPortal): The effects of background zonal and meridional winds on ENSO in a coupled GCM

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DOI	10.1175/JCLI-D-18-0822.1
	The effects of background zonal and meridional winds on ENSO in a coupled GCM
	Zhao B.; Fedorov A.
发表日期	2020
ISSN	0894-8755
起始页码	2075
结束页码	2091
卷号	33 期号:6
英文摘要	Changes in background zonal wind in the tropical Pacific are often invoked to explain changes in ENSO properties. However, the sensitivity of ENSO to mean zonal winds has been thoroughly explored only in intermediate coupled models (following Zebiak and Cane), not in coupled GCMs. The role of mean meridional winds has received even less attention. Accordingly, the goal of this study is to examine systematically the effects of both zonal (equatorial) and meridional (cross-equatorial) background winds on ENSO using targeted experiments with a comprehensive climate model (CESM). Changes in the mean winds are generated by imposing heat flux forcing in two confined regions at a sufficient distance north and south of the equator. We find that the strengthening of either wind component reduces ENSO amplitude, especially eastern Pacific SST variability, and inhibits meridional swings of the intertropical convergence zone (ITCZ). The effect of zonal winds is generally stronger than that of meridional winds. A stability analysis reveals that the strengthening of zonal and meridional winds weakens the ENSO key positive feedbacks, specifically the zonal advection and thermocline feedbacks, which explains these changes. Zonal wind enhancement also intensifies mean upwelling and hence dynamical damping, leading to a further weakening of El Niño events. Ultimately, this study argues that the zonal and, to a lesser extent, meridional wind strengthening of the past decades may have contributed to the observed shift of El Niño characteristics after the year 2000. © 2020 American Meteorological Society.
英文关键词	Climate models; Climatology; Heat flux; A-stability; Background winds; Eastern pacific; Intermediate coupled model; Intertropical convergence zone; Mean zonal winds; Meridional winds; Wind components; Wind; El Nino-Southern Oscillation; general circulation model; heat flux; intertropical convergence zone; meridional circulation; sensitivity analysis; zonal wind; 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/171402
作者单位	Yale University, New Haven, CT, United States; Department of Geology and Geophysics, Yale University, New Haven, CT, France; LOCEAN/IPSL, Sorbonne University, Paris, France
推荐引用方式 GB/T 7714	Zhao B.,Fedorov A.. The effects of background zonal and meridional winds on ENSO in a coupled GCM[J],2020,33(6).
APA	Zhao B.,&Fedorov A..(2020).The effects of background zonal and meridional winds on ENSO in a coupled GCM.Journal of Climate,33(6).
MLA	Zhao B.,et al."The effects of background zonal and meridional winds on ENSO in a coupled GCM".Journal of Climate 33.6(2020).