大气结构特征与雷暴成因

盛夏季节,宜宾雷暴的形成主要与对流层内高温高湿、风及其在对流层的中上部垂直切变小的特点相关联。西宁雷暴的形成主要与上层为深厚的干冷、下层为浅薄的暖湿、对流层的中上层风及其垂直切变大的特点相关联。分析又得到以下结论:西宁雷暴的形成又与高空冷空气加强南移、副热带急流南侧反气旋式切变得到加强和高空出现辐散相关联。

CHARAXTERISTICS OF THE ATMOSPHERIC STRUCTURE IN THUNDERSTORMS

In this paper, by using sounding data at Yibin and Xilin in China, the causes with or without thunderstorm are analysed in midsummer. The result shows that in midsummer, the causes for thunderstorm at Yibin are mainly related with high-temperature and high-humidity, wind and its weak vertical shear in the middle and upper troposphere. At Xilin the causes are mainly related with deep dry-cold air at the upper and shallow warm-wet air at the lower, wind and its strong vertical shear in the middle troposphere and the upper troposphere. Furthermore, it is found that the causes for thunderstorm at Xilin also have connection with that the upper cold air moves southwards,anticyclonic shear on the south side of subtropical jet stream strengthen and it becomes divergence at upper air.