Contrasting spatial structures of Atlantic Multidecadal Oscillation between observations and slab ocean model simulations
Contrasting spatial structures of Atlantic Multidecadal Oscillation between observations and slab ocean model simulations
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对比观测与板片海洋模型模拟之间的大西洋多年代际振荡的空间结构
DOI：
10.1007/s00382-018-4201-8
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发表时间：
2019-02
期刊：
影响因子：
4.6
通讯作者：
Li Xiang
中科院分区：
文献类型：
--
作者：
Sun Cheng;Li Jianping;Kucharski Fred;Xue Jiaqing;Li Xiang
分析比较了板片海洋模式（SOMs）和完全耦合模式的观测和模拟结果，并对大西洋年代际振荡（AMO）的空间结构进行了分析。AMO观测到的海表温度（SST）分布具有海盆尺度的环流结构，整个北大西洋海盆SST年代际变化具有高度的空间相干性。观测到的SST异常具有共同的十年尺度信号，对应于全流域平均值（即。例如，AMO）。与此相反，在SOMs（AMO）模拟AMO表现出三极状结构，与中纬度北大西洋SST表现出相反的关系与其他部分的盆地，和SOMs未能再现所观察到的强烈的空间相干性的年代际SST变化与AMO。观测到的AMO SST异常的空间相干性被确定为一个关键特征，可以用来区分AMO机制。北大西洋涛动（NAO）引起的地面热通量变化是大气强迫的热力学机制，这在很大程度上解释了SOMs中AMOs的三极型SST。NAO对AMOs的热力强迫在年际和年代际尺度上同时产生了NAO-AMOs的逆关系，并使AMOs的变率季节性地锁定在冷季。然而，NAO强迫的热力学机制不能解释观测到的NAO-AMO关系和观测到的AMO变率与暖季的季节锁相。在年代际尺度上，NAO和AMO之间存在较强的滞后关系，NAO最多领先20年，而NAO与AMO的同步相关性较弱。从海洋动力学的角度可以很好地理解这种滞后关系和AMO的空间相干性。一个时间积分NAO指数，它反映了大西洋纬向翻转环流（AMOC）的变化和北向海洋热量输送所造成的NAO强迫的累积效应，合理地捕捉到所观察到的AMO的几十年波动。进一步的分析，使用完全耦合模式模拟提供了直接的模拟证据表明，所观察到的空间相干性的年代际SST变化整个北大西洋海盆可以复制只有包括AMOC相关的海洋动力学，和AMOC作为一个共同的强迫信号，导致北大西洋SST的空间相干变化。
The spatial structure of Atlantic multidecadal oscillation (AMO) is analyzed and compared between the observations and simulations from slab ocean models (SOMs) and fully coupled models. The observed sea surface temperature (SST) pattern of AMO is characterized by a basin-wide monopole structure, and there is a significantly high degree of spatial coherence of decadal SST variations across the entire North Atlantic basin. The observed SST anomalies share a common decadal-scale signal, corresponding to the basin-wide average (i. e., the AMO). In contrast, the simulated AMO in SOMs (AMOs) exhibits a tripole-like structure, with the mid-latitude North Atlantic SST showing an inverse relationship with other parts of the basin, and the SOMs fail to reproduce the observed strong spatial coherence of decadal SST variations associated with the AMO. The observed spatial coherence of AMO SST anomalies is identified as a key feature that can be used to distinguish the AMO mechanism. The tripole-like SST pattern of AMOsin SOMs can be largely explained by the atmosphere-forced thermodynamics mechanism due to the surface heat flux changes associated with the North Atlantic Oscillation (NAO). The thermodynamic forcing of AMOsby the NAO gives rise to a simultaneous inverse NAO–AMOsrelationship at both interannual and decadal timescales and a seasonal phase locking of the AMOsvariability to the cold season. However, the NAO-forced thermodynamics mechanism cannot explain the observed NAO–AMO relationship and the seasonal phase locking of observed AMO variability to the warm season. At decadal timescales, a strong lagged relationship between NAO and AMO is observed, with the NAO leading by up to two decades, while the simultaneous correlation of NAO with AMO is weak. This lagged relationship and the spatial coherence of AMO can be well understood from the view point of ocean dynamics. A time-integrated NAO index, which reflects the variations in Atlantic meridional overturning circulation (AMOC) and northward ocean heat transport caused by the accumulated effect of NAO forcing, reasonably well captures the observed multidecadal fluctuations in the AMO. Further analysis using the fully coupled model simulations provides direct modeling evidence that the observed spatial coherence of decadal SST variations across North Atlantic basin can be reproduced only by including the AMOC-related ocean dynamics, and the AMOC acts as a common forcing signal that results in a spatially coherent variation of North Atlantic SST.
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影响因子：
4.6
作者：
J. Mecking;N. Keenlyside;R. Greatbatch
通讯作者：
J. Mecking;N. Keenlyside;R. Greatbatch
影响因子：
5.2
作者：
Rong‐Hua Zhang;T. Delworth
通讯作者：
Rong‐Hua Zhang;T. Delworth
大西洋数十年变率对西伯利亚暖季降水的远程影响
影响因子：
4.6
作者：
Sun C;Li J;Zhao S
通讯作者：
Zhao S
DOI：
10.1002/2015jd024107
发表时间：
2016-03
期刊：
Journal of Geophysical Research: Atmospheres
影响因子：
--
作者：
Y. Peings;Graham R. Simpkins;G. Magnusdottir
通讯作者：
Y. Peings;Graham R. Simpkins;G. Magnusdottir
影响因子：
--
作者：
Liping Zhang;Chunzai Wang
通讯作者：
Liping Zhang;Chunzai Wang