摘要
利用常规和加密观测资料、NCEP/NCAR再分析资料以及多普勒雷达资料,对2007年8月2日安徽北部地区发生的一次强对流天气过程进行综合分析。结果表明:中低空切变线是此次强对流天气的触发系统,地面湿度突变线对飑线的生成及发展具有指示意义。低层850hPa低涡较强的辐合,与位于高空大风速带入口区右侧的强辐散的耦合作用,导致强对流天气发生区上空生成次级反环流圈。该反环流圈从北(南)方携带干冷(暖湿)气流下沉(上升),两者交汇进而引发强对流天气的发生。在雷达回波上,飑线生成前期,少数单体不连续地排列成线,但并未连通;飑线生成后,带状特征清晰,并且反射率因子大,多处呈现三体钉状散射体;速度回波上有成熟阶段的速度模糊现象以及消亡阶段出现的逆风区。雹暴的回波具有明显的V型缺口以及速度场上风速的辐合,当逼近雷达测站时,测站上空速度场上出现了牛眼结构。
Based on the MICAPS conventional surface and upper air data, AWS observations, NCEP/NCAR reanalysis and Doppler radar data, a comprehensive analysis is carried out for a strong convection weather process occurred on Aug. 2, 2007 in northern Anhui. The results show that this process is mainly triggered by the upper and lower shear line and the humidity mutation line on the ground is the indication of the squall line formation and development. The coupled effects by the strong convergence of the low vortex on 850hPa and that at the right side of the entrance to the large wind speed zone in the upper level induce the secondary anti-circulation so as to bring out the strong convection weather process. The anti-circulation loops from the north （south） to bring the dry and cold （warm and wet） air sinking （rising） and the two air flows trigger the occurrence of the severe convective weather. On the radar echoes a bit of monomers arrange in discontinuous line during the pre-squall line. In the mature stage the squall line shows distinct zonal features where the trisomic nail appearance scatters are presented in most sections and the radar reflectivity factor is large while on the velocity echoes the velocity fuzziness in the mature stage and adverse wind area in the decaying stage gale region appears. The hailstorm echoes show clearly the V-type gap and strong convergence of the wind in the velocity field where the Bull＇s Eye Construction appears in the velocity field when it approaches to the radar station.
出处
《成都信息工程学院学报》
2009年第6期588-595,共8页
Journal of Chengdu University of Information Technology
基金
国家自然科学基金资助项目(40830955)
关键词
气象学
中尺度天气诊断分析
切变线
湿度突变线
低涡
次级环流
逆风区
速度模糊
the science of meteorology
diagnostic analysis of meso-scale weather
shear line
humidity line
low vortex
secondary circulation
adverse wind zone
velocity fuzziness
