热带地理 ›› 2017, Vol. 37 ›› Issue (4): 484-493.doi: 10.13284/j.cnki.rddl.002957

• 论文 • 上一篇    下一篇

贵州静止锋冷区高架雷暴冰雹特征及其成因

周明飞,万雪丽,罗喜平   

  1. (贵州省气象台,贵阳 550002)
  • 出版日期:2017-07-05 发布日期:2017-07-05
  • 作者简介:周明飞(1984—),女,贵州省铜仁市人,工程师,主要从事短期天气预报工作,(E-mail)zhmf1984@sina.com。
  • 基金资助:
    国家自然基金“静止锋冷区高架雷暴产生冰雹的成因及环境要素”(41265005)”;“西南山地夏季中尺度对流复合体研究”(41065003);中国气象局关键技术集成项目“贵州冰雹与短时强降水天气中尺度分析研究(CMAGJ2015M52)”

Characteristics and Causes of Elevated Thunderstorms which Produce Hail in the Cold Sector of Stationary Front in Guizhou

ZHOU Mingfei,WAN Xueli,LUO Xiping   

  1. (Guizhou Meteorological Observatory,Guiyang 550002,China)
  • Online:2017-07-05 Published:2017-07-05

摘要:

利用统计学和天气学方法对贵州近30年高架雷暴冰雹天气的统计分析发现:高架雷暴冰雹多出现在滇黔静止锋后的贵州中东部,与贵州总体冰雹分布明显不同。对典型的37次高架雷暴冰雹个例进行天气学分析发现,滇黔静止锋是判定高架雷暴的重要依据。根据静止锋强弱的变化,分为静止锋西进型、静止锋维持型和静止锋北退型三大类高架雷暴冰雹天气。分别选取3次典型个例对比分析得出:静止锋的存在使得低层有稳定的逆温层,但将抬升起始高度抬高到逆温层顶后,3次个例中均出现了一定强度的对流有效位能CAPE,同时呈现出“上干下湿”的喇叭口探空图形;对水汽条件的分析发现,低层水汽的输送均来自于锋面逆温层上的偏南气流;由锋面造成的较强垂直风切变是形成高架对流天气发展的有利条件。由于3次冰雹天气过程地理位置不同和静止锋的摆动,其锋面逆温层高度不同,锋生高度不同,前两类高架雷暴冰雹锋生过程中变形项为主要贡献项,第三类高架雷暴冰雹锋生函数先由变形项形成锋生,随后以水平辐散项为主导形成强烈锋生触发强对流天气发生发展。

关键词: 冰雹, 高架雷暴, 静止锋, 贵州

Abstract:

By using methods of synoptic and physical quantity diagnosis, elevated thunderstorms which produce hail in the cold sector of stationary front from January to April in past thirty years in Guizhou are analyzed. The results show that elevated thunderstorm is one of the important types of thunderstorms which produce hail in Guizhou in the early spring. Half of the hail cases were caused by elevated thunderstorms. Most of the elevated thunderstorms which produced hail occurred in the Mid-Eastern Guizhou, different from the spatial distribution of hail occurring in Guizhou. Analyzing the 37 typical processes of elevated thunderstorms, we find that the stationary front between Guizhou and Yunnan is the most important weather system. At 200 hPa height the impacting weather system is the strong southwest flow before the tough. At 500 hPa height the impacting weather systems are the southwest flow, west flow and active tough. When the active tough moves to east it causes cold air moving to south area on low level. On low level 700 hPa and 850 hPa, the impacting weather system is the shear. With (due to) the moving of shear the wind changes fast. On the surface the stationary front always swings between the middle of Guizhou and the east of Yunnan, and commonly stays at the area between the two provinces. According to the changes of stationary front the weather situations can be classified into three types: 1) the stationary front is moving to the west, 2) the stationary front is static, and 3) the stationary front is retreating to the north. Comparative analysis of the 3 processes shows that: because of the stationary front, low level atmosphere is stable, but it lifts the uplifted height onto the top of the stationary front, then an inversion layer and CAPE occur and the vertical instability structure appears, presenting a graphic of “dry upper-level and wet lower-level”. The analysis of vapor conditions shows that vapor comes from the southern wind above the stationary front. The analysis of vertical wind shear shows that the strong vertical wind shear on the front is beneficial for the elevated thunderstorm. Because of the differences of geographical position and the changes of stationary front, the height of the stationary front inversion layer is different and the height of frontogenesis is different. When the stationary front moves to the west affected by the cold air from north, the frontogenesis function shows that the trigger mechanism is the θse density increase on the top of inversion layer, which is caused by the shear between the north wind and south wind. As the cold air is strong and deep, the layer of shear is higher. When the stationary front is static, the trigger mechanism is same as case one, but the cold air is not strong and deep, so the layer of shear is lower. When the stationary front moves to the north, the south wind is strong. The trigger mechanisms are F2 and F3, and the two factors make the θse increase in the south of Guizhou, which is different from the case one and case two.

Key words: hail, elevated-convection, stationary front, Guizhou