气候变化领域集成服务门户(CCPortal): Walker circulation controls ENSO atmospheric feedbacks in uncoupled and coupled climate model simulations

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DOI	10.1007/s00382-020-05152-2
	Walker circulation controls ENSO atmospheric feedbacks in uncoupled and coupled climate model simulations
	Bayr T.; Dommenget D.; Latif M.
发表日期	2020
ISSN	0930-7575
起始页码	2831
结束页码	2846
卷号	54
英文摘要	Many climate models strongly underestimate the two most important atmospheric feedbacks operating in El Niño/Southern Oscillation (ENSO), the positive (amplifying) zonal surface wind feedback and negative (damping) surface-heat flux feedback (hereafter ENSO atmospheric feedbacks, EAF). This hampers a realistic representation of ENSO dynamics in these models. Here we show that the atmospheric components of climate models participating in the 5th phase of the Coupled Model Intercomparison Project (CMIP5) when forced by observed sea surface temperatures (SST), already underestimate EAF on average by 23%, but less than their coupled counterparts (on average by 54%). There is a pronounced tendency of atmosphere models to simulate stronger EAF, when they exhibit a stronger mean deep convection and enhanced cloud cover over the western equatorial Pacific (WEP), indicative of a stronger rising branch of the Pacific Walker Circulation (PWC). Further, differences in the mean deep convection over the WEP between the coupled and uncoupled models explain a large part of the differences in EAF, with the deep convection in the coupled models strongly depending on the equatorial Pacific SST bias. Experiments with a single atmosphere model support the relation between the equatorial Pacific atmospheric mean state, the SST bias and the EAF. An implemented cold SST bias in the observed SST forcing weakens deep convection and reduces cloud cover in the rising branch of the PWC, causing weaker EAF. A warm SST bias has the opposite effect. Our results elucidate how biases in the mean state of the PWC and equatorial SST hamper a realistic simulation of the EAF. © 2020, The Author(s).
语种	英语
scopus关键词	atmospheric convection; atmospheric modeling; climate modeling; cloud cover; CMIP; computer simulation; El Nino-Southern Oscillation; heat flux; sea surface temperature; surface wind; Walker circulation; zonal wind; Pacific Ocean; Pacific Ocean (Equatorial); Pomatiopsis californica
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/145551
作者单位	GEOMAR Helmholtz Centre for Ocean Research Kiel, Düsternbrooker Weg 20, Kiel, 24105, Germany; School of Mathematical Sciences, Monash University, Clayton, VIC, Australia; Cluster of Excellence “The Future Ocean”, University of Kiel, Kiel, 24105, Germany
推荐引用方式 GB/T 7714	Bayr T.,Dommenget D.,Latif M.. Walker circulation controls ENSO atmospheric feedbacks in uncoupled and coupled climate model simulations[J],2020,54.
APA	Bayr T.,Dommenget D.,&Latif M..(2020).Walker circulation controls ENSO atmospheric feedbacks in uncoupled and coupled climate model simulations.Climate Dynamics,54.
MLA	Bayr T.,et al."Walker circulation controls ENSO atmospheric feedbacks in uncoupled and coupled climate model simulations".Climate Dynamics 54(2020).