六盘山区一次非典型冰雹天气过程微物理量特征的分析

利用地面激光雨滴谱仪捕捉2017年7月14日夜间发生在六盘山区的一次强对流天气降雹过程，其降雨和降雹微物理特征表明：降雹时，粒子各项微物理特征量明显增大，其中数浓度和平均动能通量增幅最为明显，分别增长了6.3倍和13倍。降雹初期，粒径较大的冰雹粒子增长较快，随着能量的释放，对流减弱，粒径较小的冰雹粒子增加较快。Gamma型分布更适合拟合降雹前后的粒子谱。用粒子下落末速度公式V=aD^b拟合此次降雹过程中的粒子速度效果很好，相关系数超过0.98，a的变化范围在4.55～5.02之间，bWTBZ]的变化范围在0.53～0.59之间。

A case analysis of microphysical characteristics of atypical hail formation over Liupan Mountain,China

Hail is one of the most important destructive weather phenomena in Ningxia Province,China.Its circulation background and spatiotemporal distribution characteristics have been carefully studied by many researchers,but the research on hail with the newest generation of detection equipment is not very clear.This study addressed this gap by examining hail events with measurements of instantaneous precipitation intensity,total number of precipitation particles,cumulative precipitation,visibility,and radar reflectivity that were obtained using a DSG5 laser raindrop spectrometer.The precipitation and microphysical characteristics of hail falling during severe convective weather in the Liupan Mountain area of Ningxia Province on the night of July 14,2017,were systematically analyzed.The results showed as follows: (1) during the hail process,the microphysical characteristics of the precipitation particles increased significantly relative to the baseline.In particular,the number density and mean kinetic energy flux increased to 6.3 and 13 times more than their initial values,respectively.(2) In the early hailing stage,large hail particles grew faster than did smaller particles.However,with the release of energy,convection weakened and hailstones of smaller size increased rapidly.(3) Our data showed that a gamma type distribution was most suitable for fitting the particle distribution characteristics before and after the hail process.(4) Finally,we found that particle velocity during the hail falling process was well fitted by using the particle falling velocity formula V=aD^b(R²≥0.98).Fitted to our data,the constant aranged from 4.55 to 5.02,while bvaried from 0.53 to 0.59.