摘要
2006年7月6～7日高原东侧发生了一次区域性暴雨过程，与以往高原东侧暴雨过程概念模型不同的是，这次暴雨过程中没有出现低空急流，在暴雨强盛阶段伴有全风速增强。本文采用诊断分析方法，从暴雨发生所需的热力、水汽及动力条件人手，采用相当位温、水汽通量、视热源和视水汽汇、湿位涡等几个物理量对这次暴雨过程进行综合分析，以揭示了暴雨发生、发展的机制。西南涡与高温、高湿的大气条件相配合，高低空风的垂直切变及来自孟加拉湾的充沛水汽输送和辐合，为该暴雨过程提供了有利的条件。这次暴雨以对流性降水为主，视热源和视水汽汇的垂直输送作用是加热的主要贡献项，而局地变化项和平流项有相反的变化特征，其共同作用是减小对加热的贡献；该过程中湿斜压性是位涡的主要贡献项，湿位涡的演变与暴雨发展有很好的对应关系，湿位涡最大值与暴雨峰值出现时间一致，位势不稳定对触发暴雨的作用也不可忽视。
There is a regional heavy rainstorm on the east side of Qinghai-Xizang Plateau on 6-7 July 2006, which different from the general concept model of heavy rain process, there is no low level jet in this process. In this paper, using the diagnoses analysis method, starting with heatness, moisture, dynamical condition, synthetic analyses of this process through potential equivalent temperature, vapor flux, apparent heat source and apparent moist sink, moisture potential vorticity and so on, in order to understand the mechanism of the occurring and developing of the heavy rain. The results show that the Southwest Vortex match with the high temperature and moist atmosphere condition, the vertical shear of high and low wind and water vapor from Bengal gulf transportation and convergence provide favorable condition for this heavy rain process. There is very closely relation between apparent heat source and apparent moist sink, moisture potential vorticity and heavyrain, the perpendicular transportation term of apparent heat source and apparent moist sink are main contribution item, whose local change term and advective change term have contrary change character, their common action is to minish the heating for them. Baroclinic term is the - main contribution item to promote heavy rain, the maximum moisture potential vorticity comes with heavy rain, but the function of potential instability triggers heary rain can＇t be noticeable.
出处
《高原气象》
CSCD
北大核心
2008年第4期796-806,共11页
Plateau Meteorology
基金
中国气象局成都高原气象开放实验室基金课题资助
关键词
高原东侧
区域性大暴雨
诊断分析
On the east side of Qinghai-Xizang Plateau
Regional heavy rain
Diagnoses analysis
