A case study of the formation of an embedded-areal-type cloud band over Kanto Plain
A case study of the formation of an embedded-areal-type cloud band over Kanto Plain
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关东平原嵌入面型云带形成的实例研究
DOI：
10.2151/jmsj1965.73.5_857
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发表时间：
1995
影响因子：
3.1
通讯作者：
Hiroshi Nirasawa
中科院分区：
文献类型：
--
作者：
Y. Ogura;K. Tsuboki;H. Ohno;K. Kusunoki;Hiroshi Nirasawa
1992年4月22日，关东平原上空出现了一条狭窄的云带，这条云带与一个热带气旋的通过有关。它的独特特征包括快速形成和出现弧形实心云壁，而不是一排孤立的对流单元。它沿着一个更广阔的弱雨区的南部边缘发展，其方式与Bluestein和Jain（1985）确定的嵌入区域型相似。常规观测资料的中尺度分析表明，一股局地冷空气团从关东平原西北部向东南方向传播。它是由与向东传播的气旋相关的水平压力梯度力驱动的。结果表明，当冷涌与关东平原南部盛行的天气尺度西南气流发生碰撞时，云带被迫形成。进一步揭示了冷涌是一个低层中尺度气团的先导。由于它位于高空槽前的天气尺度西北气流的前方和西南气流的下方，因此得名。
A narrow cloud band developed over Kanto Plain on 22 April 1992 in association with the passage of an extratropical cyclone. Its unique features include the rapid formation and appearance of an arc-shaped solid cloud wall, rather than a line of a number of isolated convective cells. It evolved along the southern edge of a much broader weak rain area in a manner similar to the embedded areal type as identified by Bluestein and Jain (1985). A mesoscale analysis of conventional observation data reveals that a local cold air mass propagated southeastward from the northwestern part of Kanto Plain. It was driven by the horizontal pressure gradient force associated with the eastward-propagating cyclone. The cloud band was found to be forced to form when and where the cold surge collided with the synoptic-scale southwesterly flow which was prevailing over the southern part of Kanto Plain. It is further revealed that the cold surge was a leading part of a low-level mesoscale air mass which was termed as the forerunner. It was so named since it existed in front of the synoptic-scale northwesterly flow and beneath the southwesterly flow ahead of the upper-level trough.