摘要
利用常规气象观测资料、区域自动站加密观测资料、T639和FY-2卫星云图、新一代天气雷达及NECP的1°×1°再分析资料,对2014年7月5日由β中尺度系统引发的黑龙江省中部地区一次疑似龙卷和局地性强降水天气过程的环境背景、强对流在卫星云图和雷达上的发生发展过程及其物理机制、中尺度特征等进行了分析。结果表明:在高空冷涡和地面低压共同作用下,中层弱冷空气与低层强暖空气汇合,形成条件不稳定,低空急流的低层强辐合为β中尺度系统的生成提供了有利的中尺度环境场;低层的强垂直风切变使强对流环境条件进一步增强,导致多个超级单体形成和发展。对流云团发展初期强度迅速增强,在成熟阶段前期以大风天气为主,超级单体的位置出现在成熟对流云团内部上冲云顶附近;当β中尺度演变为α中尺度时,云团强度减弱,强天气过程基本结束。在雷达回波上可清晰的看到3个超级单体的生消过程,中气旋和穹窿等特征回波明显且维持时间较长,垂直风廓线和径向速度表现了风暴的垂直气流特征,较强的降水回波移至朗乡地区后强度和位置的变化极缓慢,是造成该地区持续强降水的主要原因。
In this paper,the environmental background,formation and evolution processes of a tornado-like storm and local heavy rainfall caused by a β mesoscale system on July 5,2014 in the central region of Heilongjiang province were analyzed based on conventional meteorological data,observations from regional automatic intensive weather stations,cloud images from the T639 model and FY-2 satellite,and data of newgeneration weather radar,as well as the NECP reanalysis data with 1° × 1° resolution. The results showthat this process is controlled by a cold vortex at higher altitudes and a lowpressure at ground. The weak cold air at middle altitudes invades into strong warm air at lowaltitudes,and then forms the unstable condition. Lowlevel jet（ LLJ） and strong shear at lowlevels favor the formation of β mesoscale system. The strong vertical wind shears at lowlevels enhance strong convective conditions and lead to the formation and development of three supercells. The intensity of convective clouds increases rapidly during the primary development stage. Strong winds prevail in the early mature stage,and the supercells exist in the initial of mature convective clouds and develop up to the top of clouds. With the change of β mesoscale to α mesoscale,the clouds become weak and the severe weather generally ends. The formation and extinction of three supercells are clearly found according to the radar detection. The echo from cyclone and vault is also distinct and lasts for a long period of time. The characteristics of storm are shown from the vertical wind profiles and radial vertical velocity. The strong echoes of precipitation move to Langxiang region,and their intense and location vary little,which mainly results in a persisted heavy rainfall in this region.
出处
《气象与环境学报》
2016年第3期1-9,共9页
Journal of Meteorology and Environment
基金
中国气象局预报员专项"2013年黑龙江省三次局地大暴雨过程对比分析"(CMAYBY2014-020)
黑龙江省气象局项目"弱天气尺度下强对流发展和局地要素特征"(hq2015039)共同资助
关键词
β中尺度系统
疑似龙卷
大风
强降水
β mesoscale system
Tornado-like storm
Strong wind
Heavy rainfall
