Multi-scale features of the cold air outbreak over the Japan Sea and the northwestern Pacific
Multi-scale features of the cold air outbreak over the Japan Sea and the northwestern Pacific
复制标题
日本海及西北太平洋冷空气爆发的多尺度特征
DOI：
10.2151/jmsj1965.74.6_745
复制
发表时间：
1996
影响因子：
3.1
通讯作者：
T. Akiyama
中科院分区：
文献类型：
--
作者：
K. Ninomiya;Junzo Fujimori;T. Akiyama
本文研究了1987年1月8-10日日本海和西北太平洋极地空气爆发的特征。来自亚洲大陆的极地空气爆发发生在西北太平洋上空的天气尺度气旋发展之后。逗点云起源于天气尺度气旋后方极地气流中的极地槽下。逗点云在发展过程中表现出次级冷锋的特征。当逗点云与主要锋面云带相互作用引起瞬间阻塞时，极地空气爆发加剧。极地空气从大陆向闭塞气旋的西南部突出，形成一股楔形冷空气。冷楔中的冷西风气流和气旋西北部相对温暖的东风气流之间形成了一条与云带相关的切变线。切变流中的水平热平流差导致了局地锋生。在对流层中部，一条东西向的狭长低压槽在对流层低层冷楔上方拉长。切变线锋生与中尺度气旋生成相伴发生。中尺度气旋在其成熟阶段产生了1.25 m/s的强阵风。切变线通过后，偏北冷空气爆发进一步加强。因此，本文提出了极地空气爆发的多尺度特征的概念，这对于研究亚洲大陆东部沿海和西北太平洋极地空气爆发的实现过程具有重要意义。
Features of the polar air outbreak over the Japan Sea and the northwestern Pacific are studied for the 3-day period of 8-10 January 1987. The polar air outbreak from the Asian Continent occurred following the development of a synoptic-scale cyclone over the northwestern Pacific. A comma cloud originated under a polar trough in polar air streams rearward of the synoptic-scale cyclone. The comma cloud exhibited features of the secondary cold front as it developed. The polar air outbreak was intensified when the comma cloud induced an instant occlusion by interacting with the major frontal cloud band. Polar air protruded as a wedge of cold air from the Continent toward the southwestern portion of the occluded cyclone. A shear line associated with a cloud band formed between the cold westerly streams in the cold wedge and the relatively warm easterly streams in the northwestern portion of the cyclone. The local frontogenesis took place due to the horizontal differential thermal advection in the shear flow. In the mid-troposphere, a long narrow trough of west-east orientation elongated over the cold wedge in the lower troposphere. The meso-scale cyclogenesis occurred in association with the frontogenesis in the shear line. The meso-scale cyclone caused strong gusts of ∼ 25 m/s in its mature stage. The northerly cold air outbreak was further intensified after the passage of the shear line. The present paper thus proposes the concept of the multi-scale features of the polar air outbreak, which will be important in the realization processes of the polar air outbreak over the eastern coast of the Asian continent and the northwestern Pacific.