摘要
利用MICAPS、风廓线雷达、多普勒雷达及本场c波段双偏振雷达等资料,对2021年9月30日夜间至10月 1日凌晨大连机场一次强冰雹天气过程天气特征进行了分析.结果表明:(1)850 hPa槽前较强低空西南急流带提供了水汽输送,高空槽和地面冷锋相配合,前期低层的稳定层结为强对流爆发聚集了不稳定能量,高空槽加速移动,槽后有弱冷空气冲击渤海上空的暖湿不稳定空气造成的极端强对流天气;(2)高CAPE值、适当水汽条件与急流相配合、更小的0～-20 ℃高度差和-20～-30℃高度差、垂直速度差＞40m·s-1、低空强风切变、零度层上下上升区与强上升区叠置为冰雹循环增长提供了有利环境;(3)雷达回波具有入流缺口、钩状回波、三体散射长钉、旁瓣假回波和弱回波(穹隆)—悬挂回波—回波墙的典型冰雹云结构,径向速度图具有中气旋特征.
Abstract
This paper analyzes the weather characteristics of a severe hailstorm event that occurred at Dalian Airport from the night of September 30 to the early morning of October 1,2021 with the data from MICAPS,wind profiler radar,Doppler radar and C-band dual-polarization radar.The results indicate that:(1)the strong low-level southwesterly jet stream ahead of the 850 hPa trough provided moisture transport while the upper trough and surface cold front worked in conjunction.The stable stratification in the lower levels prior to the event accumulated unstable energy for the outbreak of strong convection.The rapid movement of the upper trough combined with weak cold air behind the trough impacting the warm and moist unstable air over the Bohai Sea led to extreme convective weather;(2)high CAPE values,appropriate moisture conditions combined with the jet stream,smaller height differences between 0℃and-20℃ as well as between-20℃ and-30℃,vertical velocity differences exceeding 40 m·s-1,strong low-level wind shear,and the overlap of the ascent zone around the freezing level with the strong updraft region created a favorable environment for hail growth;(3)radar echoes exhibited typical hailstorm cloud structures such as inflow notches,hook echoes,three-body scattering spikes,sidelobe false echoes,and weak echo(vault)—suspended echo—echo wall features,while the radial velocity map displayed characteristics of a mesocyclone.
万方数据