The Internal Generation of the Atlantic Ocean Interdecadal Variability

被引:19
|
作者
Arzel, Olivier [1 ]
Huck, Thierry [1 ]
de Verdiere, Alain Colin [1 ]
机构
[1] Univ Bretagne Occidentale, Lab Oceanog Phys & Spatiale, Brest, France
关键词
Instability; Meridional overturning circulation; Ocean circulation; Planetary waves; Climate variability; Multidecadal variability; MERIDIONAL OVERTURNING CIRCULATION; SEA-SURFACE TEMPERATURE; NORTH-ATLANTIC; THERMOHALINE CIRCULATION; MULTIDECADAL VARIABILITY; HEAT-FLUX; BAROCLINIC INSTABILITY; ATMOSPHERE MODEL; DECADAL VARIABILITY; BOTTOM TOPOGRAPHY;
D O I
10.1175/JCLI-D-17-0884.1
中图分类号
P4 [大气科学(气象学)];
学科分类号
0706 ; 070601 ;
摘要
Numerical simulations of a realistic ocean general circulation model forced by prescribed surface fluxes are used to study the origin and structure of intrinsic interdecadal variability of the ocean circulation. When eddy-induced turbulent diffusivities are low enough, spontaneous oscillations of the Atlantic meridional overturning circulation (AMOC) with periods O(20) yr and amplitude O(1) Sv (1 Sv 10(6) m(3) s(-1)) emerge. The transition from the steady to the oscillatory regime is shown to be consistent with a supercritical Hopf bifurcation of the horizontal Peclet number. Adding atmospheric thermal damping is shown to have a very limited influence on the domain of existence of intrinsic variability. The spatial structure of the mode consists of a dipole of sea surface temperature (SST)/sea surface height (SSH) anomalies centered at about 50 degrees N with stronger variance in the western part of the subpolar gyre, in agreement with the observed Atlantic multidecadal oscillation (AMO) signature in this region. Specific features include a westward propagation of temperature anomalies from the source region located on the western flank of the North Atlantic Current (NAC) and a one-quarter phase lag between surface and subsurface (800 m) temperature anomalies. Local linear stability calculations including viscous and diffusive effects confirm that the North Atlantic Current is baroclinically unstable on scales of O(1000) km with growth rates of O(1) yr(-1). Both the spatial structure of the mode and the period agree in magnitude with in situ measurements in the North Atlantic, suggesting that this intrinsic ocean mode participates in the observed Atlantic bidecadal climate variability.
引用
收藏
页码:6411 / 6432
页数:22
相关论文
共 50 条
  • [21] Energetics of Multidecadal Atlantic Ocean Variability
    Dijkstra, Henk A.
    Saenz, Juan A.
    Hogg, Andrew McC
    JOURNAL OF CLIMATE, 2014, 27 (20) : 7874 - 7889
  • [22] Assessing External and Internal Sources of Atlantic Multidecadal Variability Using Models, Proxy Data, and Early Instrumental Indices
    O'Reilly, Christopher H.
    Zanna, Laure
    Woollings, Tim
    JOURNAL OF CLIMATE, 2019, 32 (22) : 7727 - 7745
  • [23] The Leading, Interdecadal Eigenmode of the Atlantic Meridional Overturning Circulation in a Realistic Ocean Model
    Sevellec, Florian
    Fedorov, Alexey V.
    JOURNAL OF CLIMATE, 2013, 26 (07) : 2160 - 2183
  • [24] Dynamics of decadal variability in the Atlantic subpolar gyre: a stochastically forced oscillator
    Born, Andreas
    Mignot, Juliette
    CLIMATE DYNAMICS, 2012, 39 (1-2) : 461 - 474
  • [25] North Atlantic warming: patterns of long-term trend and multidecadal variability
    Polyakov, Igor V.
    Alexeev, Vladimir A.
    Bhatt, Uma S.
    Polyakova, Evgenia I.
    Zhang, Xiangdong
    CLIMATE DYNAMICS, 2010, 34 (2-3) : 439 - 457
  • [26] Multicentennial Variability Driven by Salinity Exchanges Between the Atlantic and the Arctic Ocean in a Coupled Climate Model
    Jiang, Weimin
    Gastineau, Guillaume
    Codron, Francis
    JOURNAL OF ADVANCES IN MODELING EARTH SYSTEMS, 2021, 13 (03)
  • [27] Analyzing the Influence of the North Atlantic Ocean Variability on the Atlantic Meridional Mode on Decadal Time Scales
    Veiga, Sandro F.
    Giarolla, Emanuel
    Nobre, Paulo
    Nobre, Carlos A.
    ATMOSPHERE, 2020, 11 (01)
  • [28] Predictability and Decadal Variability of the North Atlantic Ocean State Evaluated from a Realistic Ocean Model
    Sevellec, Florian
    Fedorov, Alexey V.
    JOURNAL OF CLIMATE, 2017, 30 (02) : 477 - 498
  • [29] Reconciling two alternative mechanisms behind bi-decadal variability in the North Atlantic
    Ortega, Pablo
    Mignot, Juliette
    Swingedouw, Didier
    Sevellec, Florian
    Guilyardi, Eric
    PROGRESS IN OCEANOGRAPHY, 2015, 137 : 237 - 249
  • [30] Predicting the Atlantic Multidecadal Variability from Initialized Simulations
    Si, Dong
    Hu, Aixue
    Wang, Huijun
    Chao, Qingchen
    JOURNAL OF CLIMATE, 2019, 32 (24) : 8701 - 8711