摘要
应用常规天气观测资料、地面加密自动气象站资料、大风灾情报资料、京津冀地区7部多普勒天气雷达组网观测资料及VDRAS资料,从多个角度对2013年8月4日京津冀地区一次飑线过程产生的大范围大风天气过程进行了分析,结果显示:此次过程是在高空冷空气南下、低层暖湿气流北上、系统前倾及位势不稳定的有利层结条件下,由多单体风暴演变为中α尺度的强飑线所致。飑线形成于低层垂直切变加强、冷池合并之后;大风主要发生在飑线主体回波中,其次是主体回波前和中前,主体回波后很少发生。大风发生的位置取决于飑线结构中气流的性质,气流的性质与冷池前进的程度和对流的强度关系密切。大风大部分由下沉冷气流产生,少数为近地面上升暖气流导致。大风发生的范围和强度与低层风垂直切变的强度呈正比,大范围低层风垂直切变的加强增强了飑线入流和出流的强度,是大范围大风、局部强风形成的重要原因。大风发生站次与冷池的强度和范围密切相关,冷池的加强和范围的扩大加强了后侧冷入流和前侧暖入流的强度和范围,也是大范围大风形成的重要因素。
Squall line with large scale strong wind weather,which occurred in Beijing-Tianjin-Hebei area on August 4,2013,had been investigated by a variety of weather data,including the routine observation data of surface and high levels,surface intensive AWS,reports of disastrous wind,radar networking data from 7 Doppler-radars in Beijing-Tianjin-Hebei area and the VDRAS data. The investigation showed that： this weather progress was due to the development of multi-cell storm into meso-α-scale squall line under special weather conditions,involving altitude cold air southward,low-level warm air northward,system forward and favorable stratification condition of potential instability. Squall line formed after the low layer vertical shear strengthening and cool pool merging,and strong winds mostly occurred in the middle of squall line major echoes,as well as in the front and middle-front of the major echoes,but rarely occurred behind the major echoes. The locations of the strong winds depended on the property of airflow in squall line. In addition,both the property of airflow and the progress degree of cool pool had a close relationship with the convection intensity. Most strong winds generated by the sinking of cold air flow,and the warm air flow rising from the ground also led to a few strong winds. The vertical shear strength of low-level wind was proportional to the range and intensity of the strong wind. The strengthening of wide range lowlevel wind vertical shear turned out to be an important reason for the wide-range strong winds and local damage high winds. The frequencies of strong winds closely related to the strength and range of cool pool.The enhancing strength and expanding scope of cool pool were help to increase the intensity and range of back-side cold inflow and front-side warm inflow,which was considered to be another significant reason for the strong winds.
出处
《气象与环境科学》
2016年第2期90-98,共9页
Meteorological and Environmental Sciences
基金
国家重点基础研究发展计划(2014CB441402、2014CB441406)
中国气象科学研究院基本科研业务费专项(2013Z006、2014Y003)
中国气象局气象关键技术集成与应用项目(CMAGJ2014M06)
灾害天气国家重点实验室开放课题(2013LASW-B08)资助
关键词
大风
飑线
垂直切变
冷池
入流
strong wind
squall line
vertical shear
cool pool
inflow
