DOI: 10.1007/s00382-014-2057-0
Scopus记录号: 2-s2.0-84901987382
论文题名: Analysis of the Slab Ocean El Nino atmospheric feedbacks in observed and simulated ENSO dynamics
作者: Dommenget D. ; Haase S. ; Bayr T. ; Frauen C.
刊名: Climate Dynamics
ISSN: 9307575
出版年: 2014
卷: 42, 期: 2017-11-12 起始页码: 3187
结束页码: 3205
语种: 英语
英文关键词: Climate sensitivity
; Climate variability
; Cloud feedback
; El Nino Southern Oscillation
; ENSO
; General circulation models
; Tropical Pacific cold tongue
英文摘要: In a recent study it was illustrated that the El Nino Southern Oscillation (ENSO) mode can exist in the absence of any ocean dynamics. This oscillating mode exists just due to the interaction between atmospheric heat fluxes and ocean heat capacity. The primary purpose of this study is to further explore these atmospheric Slab Ocean ENSO dynamics and therefore the role of positive atmospheric feedbacks in model simulations and observations. The positive solar radiation feedback to sea surface temperature (SST), due to reduced cloud cover for anomalous warm SSTs, is the main positive feedback in the Slab Ocean El Nino dynamics. The strength of this positive cloud feedback is strongly related to the strength of the equatorial cold tongue. The combination of positive latent and sensible heat fluxes to the west and negative ones to the east of positive anomalies leads to the westward propagation of the SST anomalies, which allows for oscillating behavior with a preferred period of 6-7 years. Several indications are found that parts of these dynamics are indeed observed and simulated in other atmospheric or coupled general circulation models (AGCMs or CGCMs). The CMIP3 AGCM-slab ensemble of 13 different AGCM simulations shows unstable ocean-atmosphere interactions along the equatorial Pacific related to stronger cold tongues. In observations and in the CMIP3 and CMIP5 CGCM model ensemble the strength and sign of the cloud feedback is a function of the strength of the cold tongue. In summary, this indicates that the Slab Ocean El Nino dynamics are indeed a characteristic of the equatorial Pacific climate that is only dominant or significantly contributing to the ENSO dynamics if the SST cold tongue is sufficiently strong. In the observations this is only the case during strong La Nina conditions. The presence of the Slab Ocean ENSO atmospheric feedbacks in observations and CGCM model simulations implies that the family of physical ENSO modes does have another member, which is entirely driven by atmospheric processes and does not need to have the same spatial pattern nor the same time scales as the main ENSO dynamics. © 2014 Springer-Verlag Berlin Heidelberg. 资助项目: DFG, Deutsche Forschungsgemeinschaft
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资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/54606
Appears in Collections: 过去全球变化的重建
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作者单位: School of Mathematical Sciences, Monash University, Clayton, Australia; GEOMAR Helmholtz Centre for Ocean Research, Kiel, Germany
Recommended Citation:
Dommenget D.,Haase S.,Bayr T.,et al. Analysis of the Slab Ocean El Nino atmospheric feedbacks in observed and simulated ENSO dynamics[J]. Climate Dynamics,2014-01-01,42(2017-11-12)