Characteristics of Atmospheric Vertical Structure on Days with Thunderstorms in the Northern Kanto Plain: A statistical analysis@@@統計的解析
Characteristics of Atmospheric Vertical Structure on Days with Thunderstorms in the Northern Kanto Plain: A statistical analysis@@@統計的解析
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北关东平原雷暴日大气垂直结构特征的统计分析
DOI：
10.2151/jmsj1965.53.2_139
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发表时间：
1975
影响因子：
3.1
通讯作者：
T. Yonetani
中科院分区：
文献类型：
--
作者：
T. Yonetani
通过对两个夏季248天的垂直条件的调查，研究了北方关东平原雷暴日的层结特征。为了方便起见，气氛分为两层，上层和下层。高层高度的条件不稳定度不是雷暴发生的充分条件。当上层条件不稳定时，有雷暴日和无雷暴日的低层垂直稳定度有明显的差异。也就是说，它表明，在较低的层中的空气团的垂直运动在前者比后者更容易。研究还表明，上层条件不稳定度与下层稳定度的比值是影响雷暴发生的重要因素，而不是其值。这些条件被解释为建议对流云和它的云下层之间的相互作用，并通过假设的相互作用得到的不稳定指数。结果表明，该不稳定度指数与雷暴发生的相关性比Showalter稳定度指数高。因此，雷暴的发生与整个大气稳定度之间的关系比人们所指出的要密切得多。
Vertical conditions on 248 days during two summer seasons are investigated to study the distinctive characteristics of the stratification on days with thunderstorms in the northern Kanto plain. For the sake of convenience atmosphere is divided into two layers, upper layer and lower layer. It is recognized that high degree of conditional instability of an upper layer is not the sufficient condition for the occurrence of thunderstorms. However, there are distinct differences of vertical stabilities of a lower layer between on days with thunderstorms and on days without a thunderstorm when an upper layer is conditionally unstable. Namely, it is shown that vertical movement of an air parcel in a lower layer on the former is easier than on the latter. It is also shown that the ratio of the degree of conditional instability of an upper layer to the degree of stability of a lower layer is an important factor affecting the occurrence of thunderstorms rather than their values. These conditions are interpreted into suggesting an interaction between a convective cloud and its subcloud layer, and an instability index is obtained by assuming the interaction. It is shown that this instability index has higher association with the occurrence of thunderstorms than Showalter stability index has. Therefore, the stronger relation is suggested between the occurrence of thunderstorms and the stability of the whole atmosphere than it has been pointed out.