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DOI	10.1007/s00382-019-04660-0
	The impact of stochastic physics on the El Niño Southern Oscillation in the EC-Earth coupled model
	Yang C.; Christensen H.M.; Corti S.; von Hardenberg J.; Davini P.
发表日期	2019
ISSN	0930-7575
起始页码	2843
结束页码	2859
卷号	53 期号:2020-05-06
英文摘要	The impact of stochastic physics on El Niño Southern Oscillation (ENSO) is investigated in the EC-Earth coupled climate model. By comparing an ensemble of three members of control historical simulations with three ensemble members that include stochastics physics in the atmosphere, we find that in EC-Earth the implementation of stochastic physics improves the excessively weak representation of ENSO. Specifically, the amplitude of both El Niño and, to a lesser extent, La Niña increases. Stochastic physics also ameliorates the temporal variability of ENSO at interannual time scales, demonstrated by the emergence of peaks in the power spectrum with periods of 5–7 years and 3–4 years. Based on the analogy with the behaviour of an idealized delayed oscillator model (DO) with stochastic noise, we find that when the atmosphere–ocean coupling is small (large) the amplitude of ENSO increases (decreases) following an amplification of the noise amplitude. The underestimated ENSO variability in the EC-Earth control runs and the associated amplification due to stochastic physics could be therefore consistent with an excessively weak atmosphere–ocean coupling. The activation of stochastic physics in the atmosphere increases westerly wind burst (WWB) occurrences (i.e. amplification of noise amplitude) that could trigger more and stronger El Niño events (i.e. increase of ENSO oscillation) in the coupled EC-Earth model. Further analysis of the mean state bias of EC-Earth suggests that a cold sea surface temperature (SST) and dry precipitation bias in the central tropical Pacific together with a warm SST and wet precipitation bias in the western tropical Pacific are responsible for the coupled feedback bias (weak coupling) in the tropical Pacific that is related to the weak ENSO simulation. The same analysis of the ENSO behaviour is carried out in a future scenario experiment (RCP8.5 forcing), highlighting that in a coupled model with an extreme warm SST, characterized by a strong coupling, the effect of stochastic physics on the ENSO representation is opposite. This corroborates the hypothesis that the mean state bias of the tropical Pacific region is the main reason for the ENSO representation deficiency in EC-Earth. © 2019, The Author(s).
语种	英语
scopus关键词	air-sea interaction; climate modeling; El Nino-Southern Oscillation; numerical model; stochasticity
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/146060
作者单位	Istituto di Scienze dell’Atmosfera e del Clima, Consiglio Nazionale delle Ricerche (ISAC-CNR), Bologna, Italy; Atmospheric, Oceanic and Planetary Physics, University of Oxford, Oxford, United Kingdom; National Center for Atmospheric Research, Boulder, CO, United States; Istituto di Scienze dell’Atmosfera e del Clima, Consiglio Nazionale delle Ricerche (ISAC-CNR), Torino, Italy; Istituto di Scienze Marine, Consiglio Nazionale delle Ricerche (ISMAR-CNR), Via del Fosso del Cavaliere, 100, Rome, 00133, Italy
推荐引用方式 GB/T 7714	Yang C.,Christensen H.M.,Corti S.,et al. The impact of stochastic physics on the El Niño Southern Oscillation in the EC-Earth coupled model[J],2019,53(2020-05-06).
APA	Yang C.,Christensen H.M.,Corti S.,von Hardenberg J.,&Davini P..(2019).The impact of stochastic physics on the El Niño Southern Oscillation in the EC-Earth coupled model.Climate Dynamics,53(2020-05-06).
MLA	Yang C.,et al."The impact of stochastic physics on the El Niño Southern Oscillation in the EC-Earth coupled model".Climate Dynamics 53.2020-05-06(2019).