Prolonged effect of the stratospheric pathway in linking Barents–Kara Sea sea ice variability to the midlatitude circulation in a simplified model
Prolonged effect of the stratospheric pathway in linking Barents–Kara Sea sea ice variability to the midlatitude circulation in a simplified model
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DOI：
10.1007/s00382-017-3624-y
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发表时间：
2017-06
期刊：
影响因子：
4.6
通讯作者：
Pengfei Zhang;Yutian Wu;Karen L. Smith
中科院分区：
文献类型：
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作者：
Pengfei Zhang;Yutian Wu;Karen L. Smith
为了更好地理解解释初冬巴伦支-喀拉海（BKS）海冰变率与晚冬中纬度环流响应之间观测到的超前-滞后相关的动力机制，利用一个简化的大气环流模式进行了一系列实验，该模式具有指定的理想化近地面加热。在理想化的实验中，近地面加热后，发现一个延长的效果，可以明确地归因于平流层的路径和平流层中的长时间尺度。对Eliassen-Palm通量的分析表明，由于加热和线性建设性干涉，激发了异常向上传播的行星尺度波，削弱了平流层极涡。平流层的这种反应持续约1-2个月，同时向下迁移到对流层和地面。这种向下迁移大大放大和延长了中纬度地区的低空急流减速和中亚地区的冷空气平流。理想模式试验还表明，BKS地区是最有效的影响中纬度环流比其他地区在北极。
To better understand the dynamical mechanism that accounts for the observed lead-lag correlation between the early winter Barents–Kara Sea (BKS) sea ice variability and the later winter midlatitude circulation response, a series of experiments are conducted using a simplified atmospheric general circulation model with a prescribed idealized near-surface heating over the BKS. A prolonged effect is found in the idealized experiments following the near-surface heating and can be explicitly attributed to the stratospheric pathway and the long time scale in the stratosphere. The analysis of the Eliassen-Palm flux shows that, as a result of the imposed heating and linear constructive interference, anomalous upward propagating planetary-scale waves are excited and weaken the stratospheric polar vortex. This stratospheric response persists for approximately 1–2 months accompanied by downward migration to the troposphere and the surface. This downward migration largely amplifies and extends the low-level jet deceleration in the midlatitudes and cold air advection over central Asia. The idealized model experiments also suggest that the BKS region is the most effective in affecting the midlatitude circulation than other regions over the Arctic.