Comparison of intraseasonal East Asian winter cold temperature anomalies in positive and negative phases of the Arctic Oscillation
Comparison of intraseasonal East Asian winter cold temperature anomalies in positive and negative phases of the Arctic Oscillation
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北极涛动正负位相东亚冬季气温异常季节内比较
DOI：
10.1029/2018jd028343
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发表时间：
2018
影响因子：
--
通讯作者：
Renguang Wu
中科院分区：
文献类型：
--
作者：
Lei Song;Renguang Wu
本文研究了北极涛动（AO）的季节内变化与东亚冬季气温的关系。利用30和60天带通滤波的逐日AO指数与中国东部区域平均地面温度距平的超前滞后关系，发现冷温距平出现在AO正位相和负位相之后的概率基本相同。合成分析表明，两类年的地面温度和对流层环流异常存在显著差异。在负AO导致东亚冷异常的年份，与AO相关的气压异常延伸到欧亚大陆，导致西伯利亚高压增强，并在中高纬度地区有较大的空间覆盖范围;对流层中层波列沿着极锋急流东移，导致东亚大槽加深;由此产生的冷地面温度异常影响东亚大范围区域。在正AO导致冷异常的年份，AO相关的气压异常延伸到北美，东亚高压异常位于中纬度，空间覆盖范围相对较小，对流层中层波列沿着极锋急流在亚洲上空向南移动，在副热带亚洲上空形成低压槽，副热带波列也有补充作用;由此产生的冷地面温度异常对东亚内陆的影响相对较小。平流层和对流层变化之间的关系在两种类型的年之间似乎有显着的差异。
This study investigates the relationship between intraseasonal variations of the Arctic Oscillation (AO) and East Asian winter temperature. Based on the lead‐lag correlation between 30‐ and 60‐day band‐pass filtered daily AO index and regional mean surface temperature anomalies over eastern China, it is found that the cold temperature anomalies occur following both positive and negative AO phases with nearly the same probability. Composite analysis reveals prominent differences in surface temperature and tropospheric circulation anomalies between the two types of years. During the years when negative AO leads cold anomalies over East Asia, the AO‐related pressure anomalies extend to Eurasia, inducing an enhanced Siberian high with a large spatial coverage in midlatitude and high latitude; the midtropospheric wave train along the polar front jet takes an eastward path and induces the deepening of the East Asian trough; the resultant cold surface temperature anomalies affect a large region over East Asia. During the years when positive AO leads cold anomalies, the AO‐related pressure anomalies extend to North America and the high pressure anomalies over East Asia are located at midlatitudes with a relatively small spatial coverage; the midtropospheric wave train along the polar front jet takes a southward path over Asia, inducing the development of a trough over subtropical Asia with a supplementary contribution from a subtropical wave train; the resultant cold surface temperature anomalies influence inland East Asia with a relatively small extent. There appears to be a notable difference in the relationship between the stratospheric and tropospheric change between the two types of years.