贵州冬季一次罕见风雹天气过程分析

Analysis of a Rare Wind and Hail Weather Process in Guizhou in Winter

该文利用常规气象观测资料、多普勒雷达资料和FNL再分析资料,对2022年1月4日贵州出现的一次风雹天气过程进行分析。结果表明:此次风雹天气由高空槽、低涡切变线、低空急流、地面热低压和地面辐合线共同作用产生;降雹前有能量锋的建立,降雹期间锋区呈增强趋势;湿层配置表现为500 hPa的空气偏湿,不是明显的上干下湿层结,0℃层高度和-20℃层高度比春季降雹时的高度偏低70~100 hPa;与贵州春、夏季的雷暴大风对流参数比较,此次过程的CAPE和PWAT小于春、夏季的阈值,而DCAPE、T 75和T d85明显高于春、夏季阈值;对流风暴的影响过程分为2个阶段,第1阶段的回波带强度更强,组织性更好,形成了弓形回波复合体(BEC),并伴有后侧入流缺口(RIN),是雷暴大风出现的主要原因,持续出现的三体散射长钉(TBSS)、高悬的强回波以及宽阔的弱回波区(WER),使得第1阶段的降雹密度较大,且局地产生大冰雹;第2阶段的回波强度较弱,且组织性较差,因此只产生小冰雹,降雹密度也较小。

Based on conventional meteorological observation data,Doppler radar data and FNL reanalysis data,a hailstorm process in winter on January 4,2022 in Guizhou province was analyzed.The results show that the hailstorm process was produced by the combined action of upper trough,low vortex with shear line,low-level jet,surface thermal low pressure and surface convergence line.The energy front was established before hail shooting,and the frontal zone was strengthened during hail shooting.The wet layer configuration showed that the air was humid at 500 hPa,which was not an obvious upper-layer dry and lower-layer wet.The height of 0℃layer and-20℃layer was 70~100 hPa lower than that of spring hail.Compared with the convective parameters of thunderstorm winds in spring and summer in Guizhou province,the CAPE and PWAT value of this process were lower than the thresholds of relevant parameters in spring and summer,while the values of DCAPE,the T 75 and the T d85 were significantly higher than the thresholds of relevant parameters in spring and summer.The influence process of convective storms was divided into two stages.In the first stage,the echo intensity was strong and well organized,forming the bow echo complex(BEC)with the rear inflow notch(RIN),which was the main reason for the occurrence of thunderstorm winds.The continuous occurrence of three-body scatter spire(TBSS),high hanging strong echo and wide weak echo region(WER)made the hail density in the first stage high and locally accompanied by large hail.In the second stage,the echo intensity was weak and the organization was poor,so only small hail was generated,and the hail density was sparse.