North Atlantic Ocean control on surface heat flux on multidecadal timescales
North Atlantic Ocean control on surface heat flux on multidecadal timescales
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DOI：
10.1038/nature12268
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发表时间：
2013-07-25
期刊：
影响因子：
64.8
通讯作者：
Koltermann, Klaus Peter
中科院分区：
文献类型：
--
作者：
Gulev, Sergey K.;Latif, Mojib;Koltermann, Klaus Peter
近50年前，Bjerknes（1）提出，中纬度北大西洋上空大尺度海气相互作用的特征随时间尺度而不同：大气被认为直接驱动大多数短期年际海表温度（SST）变率，海洋对长期数十年SST和潜在的大气变率有重要贡献。虽然短时间尺度的推测是公认的，了解大西洋的SST 2，3的年代际变率（AMV）仍然是一个挑战，由于有限的海洋观测。尽管如此，AMV仍然具有重大的社会经济意义，因为它与大西洋飓风活动和萨赫勒降雨等重要气候现象有关，并且它阻碍了北大西洋地区人为信号的检测（4-6）。AMV对海洋影响的直接证据只能由表面热通量提供，这是海洋-大气通信的语言。在这里，我们提供的观测证据表明，在中纬度北大西洋和超过10年的时间尺度上，表面湍流热通量确实是由海洋驱动的，可能会迫使大气，而在较短的时间尺度上，匡威亦然，从而证实了Bjerknes猜想。这一结果，虽然在北方冬季最强，但在所有季节都存在。我们的研究结果表明，中纬度北大西洋海气相互作用的可预测性可以延伸到海洋以外的周围大陆的气候。
Nearly 50 years ago Bjerknes(1) suggested that the character of large-scale air-sea interaction over the mid-latitude North Atlantic Ocean differs with timescales: the atmosphere was thought to drive directly most short-term-interannual-sea surface temperature (SST) variability, and the ocean to contribute significantly to long-term-multidecadal-SST and potentially atmospheric variability. Although the conjecture for short timescales is well accepted, understanding Atlantic multidecadal variability (AMV) of SST2,3 remains a challenge as a result of limited ocean observations. AMV is nonetheless of major socio-economic importance because it is linked to important climate phenomena such as Atlantic hurricane activity and Sahel rainfall, and it hinders the detection of anthropogenic signals in the North Atlantic sector(4-6). Direct evidence of the oceanic influence of AMV can only be provided by surface heat fluxes, the language of ocean-atmosphere communication. Here we provide observational evidence that in the mid-latitude North Atlantic and on timescales longer than 10 years, surface turbulent heat fluxes are indeed driven by the ocean and may force the atmosphere, whereas on shorter timescales the converse is true, thereby confirming the Bjerknes conjecture. This result, although strongest in boreal winter, is found in all seasons. Our findings suggest that the predictability of mid-latitude North Atlantic air-sea interaction could extend beyond the ocean to the climate of surrounding continents.