How Robust Are the Surface Temperature Fingerprints of the Atlantic Overturning Meridional Circulation on Monthly Time Scales?
How Robust Are the Surface Temperature Fingerprints of the Atlantic Overturning Meridional Circulation on Monthly Time Scales?
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DOI：
10.1029/2017gl076759
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发表时间：
2018-04-28
影响因子：
5.2
通讯作者：
Robson, J. I.
中科院分区：
文献类型：
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作者：
Alexander-Turner, R.;Ortega, P.;Robson, J. I.
有人认为，大西洋经向翻转环流（AMOC）的变化可以在月时间尺度上驱动海表温度（SST）（Duchez等人，2016，https：//doi.org/10.1002/2017GB005667）。然而，只有11年的连续观测，这一结果在更长或不同的时间段内的有效性是不确定的。在这项研究中，我们使用了120年的控制模拟从高分辨率的气候模式来测试的鲁棒性的AMOC指纹。该模式再现了观测到的AMOC季节循环及其变率，以及观测到的5个月滞后AMOC-SST指纹来自11年的数据。然而，AMOC-SST指纹对所考虑的特定时间段非常敏感。特别是，无论是佛罗里达电流和上层海洋中的运输产生高度不一致的指纹时，使用的时间周期短于30年。因此，几十年的快速观测将是必要的，以确定真实的影响AMOC对SST在每月的时间尺度。简明的语言摘要大西洋经向翻转环流（AMOC）被认为是地球气候的一个关键因素，因为它在将热量从赤道重新分配到北大西洋和北极方面起着重要作用。因此，了解AMOC的变化如何影响更广泛的气候是气候预测的一个重要问题。不幸的是，AMOC很难测量，从2004年开始，它只在北纬26度的地方进行了连续测量。最近的一篇论文（Duchez等人，2016年，https：//doi.org/10.1002/2017GB005667）表明，这些观测结果可以用来预测未来5个月北大西洋地区的海洋表面温度。然而，鉴于观察期较短（到目前为止只有13年），我们的研究质疑这种联系是否足够强大。通过结合使用较长的观测记录，和120年的气候模拟，我们表明，AMOC和表面温度之间的联系是高度敏感的时间段考虑。因此，我们主张有必要继续目前的观测工作至少二十年，以确定AMOC预测大西洋未来几个月的潜力。
It has been suggested that changes in the Atlantic Meridional Overturning Circulation (AMOC) can drive sea surface temperature (SST) on monthly time scales (Duchez et al., 2016, https://doi.org/10.1002/2017GB005667). However, with only 11 years of continuous observations, the validity of this result over longer, or different, time periods is uncertain. In this study, we use a 120 yearlong control simulation from a high-resolution climate model to test the robustness of the AMOC fingerprints. The model reproduces the observed AMOC seasonal cycle and its variability, and the observed 5-month lagged AMOC-SST fingerprints derived from 11 years of data. However, the AMOC-SST fingerprints are very sensitive to the particular time period considered. In particular, both the Florida current and the upper mid-ocean transport produce highly inconsistent fingerprints when using time periods shorter than 30 years. Therefore, several decades of RAPID observations will be necessary to determine the real impact of the AMOC on SSTs at monthly time scales.Plain Language Summary The Atlantic Meridional Overturning Circulation (AMOC) is thought to be a key element of the Earth's climate as it plays an important role in redistributing heat from the Equator toward the North Atlantic and the Arctic. Therefore, understanding how variations in the AMOC affect the wider climate is an important question for climate prediction. Unfortunately, the AMOC is difficult to measure, and it has only been continuously measured since 2004 at the latitude of 26 degrees N. A recent paper (Duchez et al., 2016, https://doi.org/10.1002/2017GB005667) suggests that these observations can be exploited to predict the surface temperature of the ocean in the North Atlantic region up to 5 months ahead. However, given the short observational period (only 13 years so far), our study questions if this link is sufficiently robust. By combining the use of longer observational records, and a 120 yearlong simulation of the climate, we show that the link between the AMOC and surface temperatures is highly sensitive to the time epoch considered. Therefore, we advocate the need of continuing the current observational efforts for at least two more decades to robustly determine the AMOC potential for predicting the Atlantic several months ahead.