Recent global climate feedback controlled by Southern Ocean cooling
Recent global climate feedback controlled by Southern Ocean cooling
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DOI：
10.1038/s41561-023-01256-6
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发表时间：
2023-08
影响因子：
18.3
通讯作者：
Sarah M. Kang;P. Ceppi;Yue Yu;I. Kang
中科院分区：
文献类型：
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作者：
Sarah M. Kang;P. Ceppi;Yue Yu;I. Kang
全球变暖的幅度是由与气候系统的各个方面相关的气候反馈控制的，例如云。全球气候反馈是这些反馈的净效应，其时间演变被认为取决于热带太平洋海表温度模式。然而，目前的耦合气候模型未能模拟1979年至2013年期间在太平洋观察到的模式及其相关的不利负反馈。在这里，我们展示了南大洋控制全球气候反馈的机制。使用气候模式实验中，南大洋海面温度恢复到观测，我们表明，占最近南大洋冷却，这是不存在的耦合气候模型，一半的偏见，在全球气候反馈，消除云成分的偏见。这种全球性的影响是通过与东南太平洋的遥相关来介导的，在东南太平洋，遥远的海面温度异常导致强烈的层积云反馈。我们认为，由于层积云反馈过于微弱，这种南大洋驱动的模式效应在大多数气候模式中被低估了。解决这一偏差可能会将气候敏感性转移到比目前模拟的更高的值，因为南大洋在未来的预测中会加速变暖。
The magnitude of global warming is controlled by climate feedbacks associated with various aspects of the climate system, such as clouds. The global climate feedback is the net effect of these feedbacks, and its temporal evolution is thought to depend on the tropical Pacific sea surface temperature pattern. However, current coupled climate models fail to simulate the pattern observed in the Pacific between 1979 and 2013 and its associated anomalously negative feedback. Here we demonstrate a mechanism whereby the Southern Ocean controls the global climate feedback. Using climate model experiments in which Southern Ocean sea surface temperatures are restored to observations, we show that accounting for recent Southern Ocean cooling—which is absent in coupled climate models—halves the bias in the global climate feedback by removing the cloud component bias. This global impact is mediated by a teleconnection to the Southeast Pacific, where remote sea surface temperature anomalies cause a strong stratocumulus cloud feedback. We propose that this Southern Ocean-driven pattern effect is underestimated in most climate models, owing to an overly weak stratocumulus cloud feedback. Addressing this bias may shift climate sensitivities to higher values than currently simulated as the Southern Ocean undergoes accelerated warming in future projections.