On the Two Successive Supercold Waves Straddling the End of 2020 and the Beginning of 2021
On the Two Successive Supercold Waves Straddling the End of 2020 and the Beginning of 2021
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DOI：
10.1007/s00376-021-1107-x
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发表时间：
2021-10
影响因子：
5.8
通讯作者：
C. Bueh;Ji Peng;D. Lin;Bomin Chen
中科院分区：
文献类型：
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作者：
C. Bueh;Ji Peng;D. Lin;Bomin Chen
横跨2020年和2021年的两次超寒潮先后袭击中国，并造成破纪录的极低气温。本文在中期时间尺度上分析了这两次超寒潮的不同特征。第一次寒潮以喀拉海至贝加尔湖的阻塞格局为特征，第二次寒潮以亚洲大陆大范围的斜脊和斜槽为特征。寒潮前，冷空气的西北路径和超极路径共同作用，在西伯利亚关键区形成了纬向广泛的冷空气聚集。2020年和2021年的两次寒潮表现出明显的特征：（1）阻塞环流发生在乌拉尔山以北或以东，而不像前两次寒潮那样仅限于乌拉尔山;（2）亚洲阻塞型与极涡偏东的配置，使冷空气积聚的超极路径偏向东亚，并使冷空气向南爆发;（3）高、低频过程共同作用，导致强寒潮。冷空气沿着西北路径推进，与西伯利亚高压前缘的东南入侵相吻合，这与高频过程有关;而冷空气沿着超极路径移动，靠近西伯利亚高压东部边缘，这与低频过程有关。
Two supercold waves straddling 2020 and 2021 successively hit China and caused record-breaking extremely low temperatures. In this study, the distinct features of these two supercold waves are analyzed on the medium-range time scale. The blocking pattern from the Kara Sea to Lake Baikal characterized the first cold wave, while the large-scale tilted ridge and trough over the Asian continent featured the second cold wave. Prior to the cold waves, both the northwest and hyperpolar paths of cold air contributed to a zonally extensive cold air accumulation in the key region of Siberia. This might be the primary reason why strong and extensive supercold waves occur even under the Arctic amplification background.The two cold waves straddling 2020 and 2021 exhibited distinct features: (1) the blocking circulation occurred to the north or the east of the Ural Mountains and was not confined only to the Ural Mountains as it was for the earlier cold waves; (2) the collocation of the Asian blocking pattern and the polar vortex deflection towards East Asia preferred the hyperpolar path of cold air accumulation and the subsequent southward outburst; and (3) both high- and low-frequency processes worked in concert, leading to the very intense cold waves. The cold air advance along the northwest path, which coincides with the southeastward intrusion of the Siberian High (SH) front edge, is associated with the high-frequency process, while the cold air movement along the hyperpolar path, which is close to the eastern edge of the SH, is controlled by the low-frequency process.