Imprint of chaotic ocean variability on transports in the southwestern Pacific at interannual timescales
Imprint of chaotic ocean variability on transports in the southwestern Pacific at interannual timescales
复制标题
混沌海洋变化对西南太平洋年际时间尺度输运的影响
DOI：
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发表时间：
2020
期刊：
影响因子：
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通讯作者：
C. Menkes
中科院分区：
文献类型：
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作者：
S. Cravatte;G. Sérazin;T. Penduff;C. Menkes
抽象的。西南太平洋位于南亚热带海洋的分叉处
不同海洋向赤道和极地重新分配水域
电流。控制这些年际变化的过程
电流尚未被完全理解。这个问题是使用一个
概率建模策略，允许解开
大气强迫确定性海洋变化和混沌
海洋的内在变化。进行了 50 次模拟的大型集合
由相同现实驱动的相同海洋环流模型（OGCM）
大气强迫和仅因小的初始扰动而不同的是
分析了 1980 年至 2015 年。我们的研究结果表明，在西南太平洋，
输运的年际变化主要受混沌影响
南纬 20∘ 以南的海洋变化。在热带地区，而
输运和涡动能调制的年际变化是
很大程度上是确定性的，并由厄尔尼诺-南方涛动（ENSO）解释，
海洋非线性过程仍然可以解释 10% 到 20%
它们的年际差异很大。强混沌方差区域
通常与高中尺度活动区域一致，这表明
自发逆级联从中尺度到较低频率起作用
和更大的规模。低频海洋的时空特征
混沌变异性是复杂的，但在一定范围内具有空间相干性
地区。在副热带逆流区，它们表现为
年际变化、纬向拉长的交流电结构，同时
在EAC（东澳大利亚洋流）地区，它们呈涡流状。鉴于此
大规模混乱海洋波动的强烈印记，我们的结果
质疑年际变率对大气强迫的归因
通过逐点观察和单成员模拟得出该区域的结果。
Abstract. The southwestern Pacific Ocean sits at a bifurcation where southern subtropical
waters are redistributed equatorward and poleward by different ocean
currents. The processes governing the interannual variability of these
currents are not completely understood. This issue is investigated using a
probabilistic modeling strategy that allows disentangling the
atmospherically forced deterministic ocean variability and the chaotic
intrinsic ocean variability. A large ensemble of 50 simulations performed with
the same ocean general circulation model (OGCM) driven by the same realistic
atmospheric forcing and only differing by a small initial perturbation is
analyzed over 1980–2015. Our results show that, in the southwestern Pacific, the
interannual variability of the transports is strongly dominated by chaotic
ocean variability south of 20∘ S. In the tropics, while the
interannual variability of transports and eddy kinetic energy modulation are
largely deterministic and explained by the El Niño–Southern Oscillation (ENSO),
ocean nonlinear processes still explain 10 % to 20 % of
their interannual variance at large scale. Regions of strong chaotic variance
generally coincide with regions of high mesoscale activity, suggesting that a
spontaneous inverse cascade is at work from the mesoscale toward lower frequencies
and larger scales. The spatiotemporal features of the low-frequency oceanic
chaotic variability are complex but spatially coherent within certain
regions. In the Subtropical Countercurrent area, they appear as
interannually varying, zonally elongated alternating current structures, while
in the EAC (East Australian Current) region, they are eddy-shaped. Given this
strong imprint of large-scale chaotic oceanic fluctuations, our results
question the attribution of interannual variability to the atmospheric forcing
in the region from pointwise observations and one-member simulations.
年际至数十年时间尺度上大西洋经向翻转环流的内在变化
影响因子：
3.5
作者：
Grégorio S
通讯作者：
Grégorio S