摘要
2015年5月6日夜间,河南省西北部出现了冰雹、飑线和大风灾害性天气。利用常规观测资料、NCEP(1°×1°)再分析资料及郑州多普勒雷达回波资料,对这次弱降水环流背景下的飑线冰雹过程进行数值分析。结果发现:常规天气尺度环流形势不利于对这次飑线冰雹过程的预判,借助中尺度分析与落区围区法能较好地预报这次冰雹飑线过程;豫西北上空CAPE能量场较弱,水汽条件和不稳定能量也不利于强降水的产生,但由于冷平流入侵和高温高湿不稳定能量在豫西北上空不断堆积,以及冷锋入侵和垂直风切变较大,致使豫西北地区存在对流触发机制;低层辐合、高层辐散的垂直层结结构和垂直上升运动的不断加深,使强对流加强并维持,导致形成冰雹和飑线;-20℃层和0℃层高度适宜,有利于豫西北降雹;V型缺口、雷达反射率因子特征及阵风锋和飑线南北两端的速度场分布,对冰雹和大风预报有较好的指示意义。
Northwest of Henan appeared hail,squall line and strong wind severe weather at the night of May 6,2015. We performed numerical analysis of this hail squall line process under the background of weak precipitation circulation by using conventional observation data,NCEP reanalyzed( 1° × 1°) data and Zhengzhou doppler radar data. The results showed: general synoptic scale circulation situation is not conducive to the anticipation of the hail squall line process,by means of mesoscale analysis and fenced area drop zone method could forecast the hail squall line better. The CAPE energy field on northwest of Henan was comparatively weak,unstable energy and water vapor condition were not conducive to heavy rain,but because of the invasion of cold advection and continued accumulation of instability energy of high temperature and humidity,cold front intrusion and greater vertical wind shear,there were convection triggering mechanism over northwest Henan. The vertical layer structure of low-level convergence and upper-level divergence along with deepening vertical upward motion made the strong convection strengthening and maintaining,resulted in the formation of hail and squall lines. The height of-20 ℃ and 0 ℃layers were suitable conducive to the hail on northwest of Henan. The V-notch,radar reflectivity characteristics,gust fronts and speed field distribution on north and south ends of squall line led to a better indicative significance for strong wind and hail forecast.
出处
《气象与环境科学》
2017年第3期41-49,共9页
Meteorological and Environmental Sciences
基金
河南省气象局科技攻关项目"四大怀药系列化气象服务技术研究(Z201007)"资助
关键词
冰雹
飑线
中尺度分析
触发及维持机制
组合反射率
基速度
hail
squall line
mesoscale analysis
triggering and maintenance mechanism
composite reflectivity
base speed
