Robustness of the stratospheric pathway in linking the Barents-Kara Sea sea ice variability to the mid-latitude circulation in CMIP5 models
Robustness of the stratospheric pathway in linking the Barents-Kara Sea sea ice variability to the mid-latitude circulation in CMIP5 models
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DOI：
10.1007/s00382-018-4576-6
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发表时间：
2019-07-01
期刊：
影响因子：
4.6
通讯作者：
Wu, Yutian
中科院分区：
文献类型：
--
作者：
De, Bithi;Wu, Yutian
这项研究探讨了平流层路径将秋末和初冬巴伦支-卡拉海海冰变化与随后冬季中纬度环流联系起来的鲁棒性。两组模型从耦合模式相互比较项目第5阶段（CMIP 5）档案，一个具有良好的解决平流层（高顶模型）和其他的一个解决平流层（低顶模型）进行了探讨，以区分平流层路径的作用。结果表明，总体而言，高顶模式能够捕捉到持续的中纬度环流响应在随后的冬季。然而，由于缺乏平流层的变化，低顶模式的响应较弱，持续时间也不长。涡动热通量的分析表明，更强的垂直波传播导致了更强的反应，平流层极涡在高顶模式。特别是，它表明，纬向波-2涡动热通量是至关重要的，在导致更强的线性建设性干扰的气候波的高顶模式。结果表明，CMIP 5高顶模式的多模式集合能够捕捉到海冰变化对中纬度环流的长期影响，并在这方面优于低顶模式。我们的研究表明，平流层在气候模式中的代表性在放大和扩展中纬度环流响应方面起着重要的作用。
This study investigates the robustness of the stratospheric pathway in linking the sea ice variability over the Barents-Kara Sea in late autumn and early winter to the mid-latitude circulation in the subsequent winter. Two groups of models from the Coupled Model Intercomparison Project phase 5 (CMIP5) archive, one with a well-resolved stratosphere (high-top models) and the other with a poorly-resolved stratosphere (low-top models) are explored to distinguish the role of the stratospheric pathway. The results show that, collectively, high-top models are able to capture the persistent mid-latitude circulation response in the subsequent winter. The response in low-top models is, however, weaker and not as long-lasting most likely due to lack of stratospheric variability. Analysis of eddy heat flux reveals that stronger vertical wave propagation leads to a stronger response in stratospheric polar vortex in high-top models. In particular, it shows that zonal wave-2 eddy heat flux is crucial in leading to a stronger linear constructive interference with the climatological waves in high-top models. The results find that multi-model ensemble of CMIP5 high-top models is able to capture the prolonged impact of sea ice variability on the mid-latitude circulation and out performs the low-top models in this regard. Our study suggests that the representation of the stratosphere in climate models plays an important role in amplifying and extending the mid-latitude circulation response.