摘要
分析了2002年初夏发生在高原东侧的一次特大暴雨, 认为这次暴雨的成因是新疆低槽与高原槽合并东移并引导较强冷空气在高原东侧与四川至陕西的西南暖湿气流交汇而形成的。高空西风急流增强、我国东部高压的阻挡及低层偏南暖湿气流的加强、北伸为发生暴雨提供了有利条件。冷锋前暖区内中β尺度对流系统(MβCSs)的活跃直接导致了特大暴雨的发生。低层中尺度辐合系统与中β尺度对流云团的活动、大暴雨出现的时间和落区等密切相关。中尺度对流系统(MCSs)散度垂直分布的特殊结构, 即从对流层低层到高层存在的辐合—辐散“双重结构”对大暴雨时强烈上升运动和深对流形成有着重要作用。
An extreme heavy storm rain on the east side of Qinghai-Xizang Plateau in early summer of 2002 was analyzed. The result showed that the cause of heavy storm rain was the low trough in Xinjiang combined with the Plateau trough, and lead to the convergence of strong cold air and southwest airflow of warm and moist from Sichuan to Shaanxi on the east side of Qinghai-Xiang Plateau. The strengthening of westerly jet in upper level, forming of blocking high in Eastern China, strengthening and extending northward of the warm and moist southerly airflows in low level provide the advantageous conditions for heavy storm rain. The activity of meso-β-scale convective system before warm area of cold front directly cause local heavy storm rain, mesoscale convergence system in low level is closely related to the activity of meso-β-scale convective cloud cluster, timing and precipitation region of heavy storm rain. The especial structure of vertical distribution of divergence in mesoscale convective system, namely the double structures of convergence-divergence from lower levels of troposphere to upper level, has an important role in forming strong ascending motion and deep convective formation of heavy storm rain.
出处
《高原气象》
CSCD
北大核心
2005年第2期232-239,共8页
Plateau Meteorology
基金
陕西省2001年科技计划项目(2001K09-G7)资助
关键词
中尺度对流系统
特大暴雨
青藏高原
形成原因
对流
On the east side of Plateau
Mesoscale convective system
Extreme heavy storm rain
