DOI: 10.1175/JCLI-D-17-0168.1
Scopus记录号: 2-s2.0-85040953046
论文题名: Intrinsic and atmospherically forced variability of the AMOC: Insights from a large-ensemble ocean hindcast
作者: Leroux S. ; Penduff T. ; Bessières L. ; Molines J.-M. ; Brankart J.-M. ; Sérazin G. ; Barnier B. ; Terray L.
刊名: Journal of Climate
ISSN: 8948755
出版年: 2018
卷: 31, 期: 3 起始页码: 1183
结束页码: 1203
语种: 英语
英文关键词: Atlantic Ocean
; Ensembles
; Interannual variability
; Meridional overturning circulation
; Oceanic variability
Scopus关键词: Climate change
; Sea ice
; Stochastic systems
; Atlantic Ocean
; Ensembles
; Interannual variability
; Meridional overturning circulations
; Oceanic variabilities
; Oceanography
; annual variation
; atmospheric forcing
; ensemble forecasting
; hindcasting
; meridional circulation
; overturn
; sea ice
; Atlantic Ocean
英文摘要: This study investigates the origin and features of interannual-decadal Atlantic meridional overturning circulation (AMOC) variability from several ocean simulations, including a large (50 member) ensemble of global, eddy-permitting (1/4°) ocean-sea ice hindcasts. After an initial stochastic perturbation, each member is driven by the same realistic atmospheric forcing over 1960-2015. The magnitude, spatiotemporal scales, and patterns of both the atmospherically forced and intrinsic-chaotic interannual AMOC variability are then characterized from the ensemble mean and ensemble spread, respectively. The analysis of the ensemble-mean variability shows that the AMOC fluctuations north of 40°N are largely driven by the atmospheric variability, which forces meridionally coherent fluctuations reaching decadal time scales. The amplitude of the intrinsic interannual AMOC variability never exceeds the atmospherically forced contribution in the Atlantic basin, but it reaches up to 100% of the latter around 35°S and 60% in the Northern Hemisphere midlatitudes. The intrinsic AMOC variability exhibits a large-scale meridional coherence, especially south of 25°N. An EOF analysis over the basin shows two large-scale leading modes that together explain 60% of the interannual intrinsic variability. The first mode is likely excited by intrinsic oceanic processes at the southern end of the basin and affects latitudes up to 40°N; the second mode is mostly restricted to, and excited within, the Northern Hemisphere midlatitudes. These features of the intrinsic, chaotic variability (intensity, patterns, and random phase) are barely sensitive to the atmospheric evolution, and they strongly resemble the "pure intrinsic" interannual AMOC variability that emerges in climatological simulations under repeated seasonal-cycle forcing. These results raise questions about the attribution of observed and simulated AMOC signals and about the possible impact of intrinsic signals on the atmosphere. © 2018 American Meteorological Society. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/111679
Appears in Collections: 气候减缓与适应
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作者单位: Université Grenoble Alpes, CNRS, IRD, Grenoble-INP, IGE, Grenoble, France; Ocean Next, Grenoble, France; CNRS/CERFACS, CECI UMR 5318, Toulouse, France; LEGOS, Université de Toulouse, IRD, CNES, CNRS, UPS, Toulouse, France
Recommended Citation:
Leroux S.,Penduff T.,Bessières L.,et al. Intrinsic and atmospherically forced variability of the AMOC: Insights from a large-ensemble ocean hindcast[J]. Journal of Climate,2018-01-01,31(3)