Recurrence of Intraseasonal Cold Air Outbreak during the 2009/2010 Winter in Japan and its Ties to the Atmospheric Condition over the Barents-Kara Sea
Recurrence of Intraseasonal Cold Air Outbreak during the 2009/2010 Winter in Japan and its Ties to the Atmospheric Condition over the Barents-Kara Sea
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DOI：
10.2151/sola.2011-007
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发表时间：
2011-02
期刊：
影响因子：
1.9
通讯作者：
M. Hori;J. Inoue;T. Kikuchi;M. Honda;Y. Tachibana
中科院分区：
文献类型：
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作者：
M. Hori;J. Inoue;T. Kikuchi;M. Honda;Y. Tachibana
2009/2010年冬季，日本及东亚地区冷空气频繁爆发。尽管日本主要岛屿的冬季平均气温略为正值（DJF 平均气温+0.81°C，NDJFM 平均气温+0.71°C），但整个季节气温反复下降非常明显。对这个异常冬季的一个解释是北极涛动（AO）从十二月持续到一月中旬的极端负面状况。然而，仅靠 AO 并不能充分解释 11 月的冷空气爆发或其季节内周期性。对 12 月 18 日袭击日本的冷空气爆发的案例研究显示，巴伦支海-喀拉海上方形成了一条异常脊，导致西西伯利亚上空冷空气积聚。随后，气压异常向西移动，形成阻塞高压，在下游形成波列模式，将冷空气平流向东流向东亚和日本。在整个赛季的多个案例中，事件的顺序也很明显。这项研究表明，巴伦支海-喀拉海的大气状况与欧亚大陆上空的冷空气积聚之间在季节内时间尺度上存在很强的系统性联系，导致东亚和日本上空异常冷空气的爆发。该机制还可以对极端冬季条件（例如 2010/2011 年冬季观察到的情况）提供解释。
In the winter of 2009/2010, Japan and the East Asian region experienced a frequent occurrence of cold air outbreaks. Although the winter average temperature in the Japan main islands was slightly positive (+0.81°C for DJF average and +0.71°C for NDJFM average), repeated decline in temperature was notable throughout the season. One explanation for this abnormal winter season is the extremely negative condition of the Arctic Oscillation (AO) that persisted from December to mid-January. However, AO alone does not provide sufficient explanation for the cold air outbreak during November or its intraseasonal periodicity. A case study of the cold air outbreak that reached Japan on Dec. 18 reveals an anomalous ridge forming over the Barents-Kara Sea, which leads to the cold air accumulation over western Siberia. The pressure anomaly subsequently shifted westward to mature into a blocking high which created a wave-train pattern downstream, advecting the cold air eastward towards East Asia and Japan. The sequence of events was also apparent in multiple cases throughout the season. This study suggests that there is a strong and systematic linkage in the intraseasonal timescale between the atmospheric condition over the Barents-Kara Sea and the cold air accumulation over the Eurasian continent, leading to the anomalous cold air outbreak over East Asia and Japan. The mechanism may also provide explanation to extreme winter conditions such as those observed during the winter of 2010/2011.