Dynamical Attribution of Recent Variability in Atlantic Overturning
Dynamical Attribution of Recent Variability in Atlantic Overturning
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DOI：
10.1175/jcli-d-15-0727.1
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发表时间：
2016-05-01
影响因子：
4.9
通讯作者：
Marshall, David P.
中科院分区：
文献类型：
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作者：
Pillar, Helen R.;Heimbach, Patrick;Marshall, David P.
将观测到的大西洋纬向翻转环流（AMOC）的变率归因于过去地表强迫的变化具有挑战性，但对于检测人为强迫的任何影响和减少未来气候预测的不确定性至关重要。在这里，定量估计的单独贡献，风和浮力迫使AMOC变化在25度N。这些估计是通过将观测到的大气异常投射到基于模型的AMOC对过去15年地表风、热和淡水强迫敏感性的动态模式上来实现的。本地风强迫被证明占主导地位的AMOC变率在短时间尺度上，而副极地热通量占主导地位的十年时间尺度上。重建的传输时间序列成功再现了RAPID-MOCHA观测到的大部分年际变化。然而，RAPID-MOCHA时间序列中明显的十年趋势没有被捕捉到，这需要改进至少在过去二十年中海洋对副极地热通量的调整的模型表示，并突出了持续监测北大西洋高纬度的重要性。
Attributing observed variability of the Atlantic meridional overturning circulation (AMOC) to past changes in surface forcing is challenging but essential for detecting any influence of anthropogenic forcing and reducing uncertainty in future climate predictions. Here, quantitative estimates of separate contributions from wind and buoyancy forcing to AMOC variations at 25 degrees N are obtained. These estimates are achieved by projecting observed atmospheric anomalies onto model-based dynamical patterns of AMOC sensitivity to surface wind, thermal, and freshwater forcing over the preceding 15 years. Local wind forcing is shown to dominate AMOC variability on short time scales, whereas subpolar heat fluxes dominate on decadal time scales. The reconstructed transport time series successfully reproduces most of the interannual variability observed by RAPID-MOCHA. However, the apparent decadal trend in the RAPID-MOCHA time series is not captured, requiring improved model representation of ocean adjustment to subpolar heat fluxes over at least the past two decades and highlighting the importance of sustained monitoring of the high-latitude North Atlantic.