Atlantic Multidecadal Variability and Associated Climate Impacts Initiated by Ocean Thermohaline Dynamics
Atlantic Multidecadal Variability and Associated Climate Impacts Initiated by Ocean Thermohaline Dynamics
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DOI：
10.1175/jcli-d-19-0530.1
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发表时间：
2020-02-01
影响因子：
4.9
通讯作者：
Danabasoglu, Gokhan
中科院分区：
文献类型：
--
作者：
Kim, Who M.;Yeager, Stephen;Danabasoglu, Gokhan
大西洋数十年变率（AMV）的海面温度（SST）特征是周边地区气候变率的关键驱动因素。低频大西洋经向翻转环流（AMOC）变化经常被认为是 AMV 相关海温异常的关键驱动机制。然而，AMV 和数十年 AMOC 变异的起源仍然是活跃研究和争论的领域。在这里，我们利用耦合系综实验来分离气候对拉布拉多海北大西洋涛动相关浮力的响应，结果表明海洋动力变化是 AMV 和相关气候影响的重要驱动因素。通过将海洋驱动的副极地海温信号传输到盆地的其他地区（包括热带北大西洋），大气遥相关在呈现完整的 AMV 模式方面也发挥着重要作用。因此，在我们的实验中，大气对热带 AMV 的反应仅限于夏季大西洋区域相对较小的区域，这表明在广泛采用的 AMV 起搏器实验方案中，大气对热带 AMV 的反应可能被高估。
The sea surface temperature (SST) signature of Atlantic multidecadal variability (AMV) is a key driver of climate variability in surrounding regions. Low-frequency Atlantic meridional overturning circulation (AMOC) variability is often invoked as a key driving mechanism of AMV-related SST anomalies. However, the origins of both AMV and multidecadal AMOC variability remain areas of active research and debate. Here, using coupled ensemble experiments designed to isolate the climate response to buoyancy forcing associated with the North Atlantic Oscillation in the Labrador Sea, we show that ocean dynamical changes are the essential drivers of AMV and related climate impacts. Atmospheric teleconnections also play an important role in rendering the full AMV pattern by transmitting the ocean-driven subpolar SST signal into the rest of the basin, including the tropical North Atlantic. As such, the atmosphere response to the tropical AMV in our experiments is limited to a relatively small area in the Atlantic sector in summertime, suggesting that it could be overestimated in widely adopted protocols for AMV pacemaker experiments.