DOI: 10.1007/s00382-017-3799-2
Scopus记录号: 2-s2.0-85023767791
论文题名: Mean-state dependence of ENSO atmospheric feedbacks in climate models
作者: Bayr T. ; Latif M. ; Dommenget D. ; Wengel C. ; Harlaß J. ; Park W.
刊名: Climate Dynamics
ISSN: 9307575
出版年: 2018
卷: 50, 期: 2018-09-10 起始页码: 3171
结束页码: 3194
语种: 英语
Scopus关键词: climate feedback
; climate modeling
; CMIP
; damping
; El Nino-Southern Oscillation
; heat flux
; sea surface temperature
; Walker circulation
; zonal wind
; Pacific Ocean
; Pacific Ocean (Equatorial)
英文摘要: We investigate the dependence of ENSO atmospheric feedbacks on the mean-state in a perturbed atmospheric physics ensemble with the Kiel Climate Model (KCM) and in CMIP5 models. Additionally, uncoupled simulations are conducted with the atmospheric component of the KCM to obtain further insight into the mean-state dependence. It is found that the positive zonal wind feedback and the negative heat flux feedback, with the short-wave flux as dominant component, are strongly linearly related through sea surface temperature (SST) and differences in model physics are less important. In observations, strong zonal wind and heat flux feedbacks are caused by a convective response in the western central equatorial Pacific (Niño4 region), resulting from an eastward (westward) shift of the rising branch of the Walker Circulation (WC) during El Niño (La Niña). Many state-of-the-art climate models exhibit an equatorial cold SST bias in the Niño4 region, i.e. are in a La Niña-like mean-state. Therefore they simulate a too westward located rising branch of the WC (by up to 30°) and only a weak convective response. Thus, the position of the WC determines the strength of both the amplifying wind and usually damping heat flux feedback, which also explains why biases in these two feedbacks partly compensate in many climate models. Furthermore, too weak atmospheric feedbacks can cause quite different ENSO dynamics than observed, while enhanced atmospheric feedbacks lead to a substantial improvement of important ENSO properties such as seasonal ENSO phase locking and asymmetry between El Niño and La Niña. Differences in the mean-state SST are suggested to be a major source of ENSO diversity in current climate models. © 2017, Springer-Verlag GmbH Germany. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/109340
Appears in Collections: 影响、适应和脆弱性 气候变化事实与影响
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作者单位: GEOMAR Helmholtz Centre for Ocean Research, Düsternbrooker Weg 20, Kiel, 24105, Germany; Cluster of Excellence “The Future Ocean”, University of Kiel, Kiel, 24105, Germany; School of Mathematical Sciences, Monash University, Clayton, VIC, Australia
Recommended Citation:
Bayr T.,Latif M.,Dommenget D.,et al. Mean-state dependence of ENSO atmospheric feedbacks in climate models[J]. Climate Dynamics,2018-01-01,50(2018-09-10)