Locally and Remotely Forced Subtropical AMOC Variability: A Matter of Time Scales
Locally and Remotely Forced Subtropical AMOC Variability: A Matter of Time Scales
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本地和远程强迫的副热带 AMOC 变化：时间尺度问题
DOI：
10.1175/jcli-d-19-0844.1
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发表时间：
2020
影响因子：
4.9
通讯作者：
T. Penduff
中科院分区：
文献类型：
--
作者：
Q. Jamet;W. Dewar;N. Wienders;B. Deremble;S. Close;T. Penduff
低频驱动北大西洋经向翻转环流（AMOC）变率的机制对于准确的气候预测具有重要意义。虽然亚极环流区已被确定为产生气候时标信号的首选区域，但其向南传播仍在考虑中，这使快速气候变化-经向翻转环流和热通量阵列-西部边界时间序列（Rapid - moha - wbts）项目提供的观测时间序列的解释变得复杂。在这项研究中，我们的目的是分离出局地大气强迫和远源信号对副热带低频AMOC变率的各自贡献。为此，我们分析了一组四组区域（20°S-55°N）涡旋分解（1/12°）北大西洋结构，其中地表强迫和开放边界条件从完全变化（现实）到每年重复的信号交替排列。他们的分析表明，在年际时间尺度（2-10年）上，当地的大气强迫信号占主导地位，而由边界施加的信号则负责频谱的年代际（10-30年）部分。由于这种明显的时间尺度分离，我们表明，尽管间环流区表现出特殊性，但大部分副热带AMOC变率可以理解为这两个信号的线性叠加。最后，我们发现，在年代际尺度上，边界强迫AMOC变率既有北方的来源，也有南方的来源，尽管前者占主导地位，包括在RAPID阵列（26.5°N）的位置。
Mechanisms driving the North Atlantic meridional overturning circulation (AMOC) variability at low frequency are of central interest for accurate climate predictions. Although the subpolar gyre region has been identified as a preferred place for generating climate time-scale signals, their southward propagation remains under consideration, complicating the interpretation of the observed time series provided by the Rapid Climate Change–Meridional Overturning Circulation and Heatflux Array–Western Boundary Time Series (RAPID–MOCHA–WBTS) program. In this study, we aim at disentangling the respective contribution of the local atmospheric forcing from signals of remote origin for the subtropical low-frequency AMOC variability. We analyze for this a set of four ensembles of a regional (20°S–55°N), eddy-resolving (1/12°) North Atlantic oceanic configuration, where surface forcing and open boundary conditions are alternatively permuted from fully varying (realistic) to yearly repeating signals. Their analysis reveals the predominance of local, atmospherically forced signal at interannual time scales (2–10 years), whereas signals imposed by the boundaries are responsible for the decadal (10–30 years) part of the spectrum. Due to this marked time-scale separation, we show that, although the intergyre region exhibits peculiarities, most of the subtropical AMOC variability can be understood as a linear superposition of these two signals. Finally, we find that the decadal-scale, boundary-forced AMOC variability has both northern and southern origins, although the former dominates over the latter, including at the site of the RAPID array (26.5°N).
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经向翻转环流在年际到年际时间尺度上的混沌变化
影响因子：
3.2
作者：
Hirschi J
通讯作者：
Hirschi J
影响因子：
5.2
作者：
D. Smeed;S. Josey;C. Beaulieu;W. Johns;B. Moat;E. Frajka‐Williams;D. Rayner;C. Meinen;M. Baringer-M
通讯作者：
D. Smeed;S. Josey;C. Beaulieu;W. Johns;B. Moat;E. Frajka‐Williams;D. Rayner;C. Meinen;M. Baringer-M
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
十年预测系统中拉布拉多海温度和盐度变化对密度和副极地 AMOC 的影响
影响因子：
5.2
作者：
Menary M
通讯作者：
Menary M
影响因子：
64.8
作者：
Biastoch, A.;Boening, C. W.;Lutjeharms, J. R. E.
通讯作者：
Lutjeharms, J. R. E.