浙江春季两次飑线的环境场条件和多普勒雷达特征对比分析  

Comparison of Ambient Conditions and Doppler Radar Characteristic of Two Spring Squall-line Processes in Zhejiang Province

作　　者：毛程燕 汪晨 龚理卿 廖君钰 李浩文 Mao Chengyan;Wang Chen;Gong Liqing;Liao Junyu;Li Haowen(Quzhou Meteorological Office, Quzhou 324000, China;Guangzhou Meteorological Observatory, Guangzhou 510080, China)

机构地区：[1]衢州市气象局,浙江衢州324000 [2]广州市气象台,广州510080

出　　处：《气象与环境科学》2021年第3期31-38,共8页Meteorological and Environmental Sciences

基　　金：浙江省气象局预报员专项项目(2018YBY05);衢州市气象局一般项目(2018QZ08)。

摘　　要：利用常规地面和高空观测、衢州多普勒天气雷达及NCEP/NCAR再分析等资料,分析了2018年3月4日(简称“3·4”)和2019年4月9日(简称“4·9”)发生在浙江省的两次飑线过程。结果表明:两次过程均发生在前倾槽和地面倒槽配置下,动力结构极不稳定,飑线在地面辐合线附近触发,有上干下湿的“喇叭口”层结特征,但两次过程在热力和动力条件、回波组织性结构上有明显差异。“3·4”飑线过程南北槽同位相叠加,南支槽更深厚,高低层温差、垂直风切变、升温幅度均较“4·9”飑线过程的强,且0℃层和-20℃层高度的条件前者更有利于大冰雹发展。从雷达回波上,两次过程都出现了低仰角速度大值区、高悬的强回波、低层弱回波区、中层回波悬垂、VIL跃增等超级单体回波特征。“3·4”过程弓形回波特征更明显,雷暴大风和冰雹出现时伴有多个中气旋,“4·9”过程在大风出现时,不密实的线状回波上只出现弱切变,对流组织性也不如前者,因此,前者对流强度更强,影响范围更广。Two squall-line processes that occurred in Zhejiang province on 4 March 2018(a.k.a‘3·4’)and 9 April,2019(a.k.a‘4·9’)are analyzed by using surface and high-altitude conventional observations,Doppler weather radar data of Quzhou and NCEP/NCAR reanalysis data.The results show that both of the squall-line processes occurred under the circulation patterns of forward-tilting trough,surface inverted trough and extremely unstable dynamic structure,and were triggered near surface convergence line with the stratification feature of dry upper level and wet lower level.However,there were significant differences in the thermal-dynamic conditions and radar echo characteristics during the two processes.During the‘3·4’squall-line process,the South and North troughs overlapped in phase,the South trough was even deeper,and the temperature difference between the upper and lower levels,strong vertical wind shear and heating range near the surface were all stronger than those of the‘4·9’process.Besides,the conditions of 0°C and-20℃layer height were more beneficial to the development of large hail in the‘3·4’process.In addition,from the radar echo chart it is seen that both the‘3·4’and‘4·9’processes had supercell echo characteristics such as high value areas of velocity at low elevations,high hanging strong echoes,low-level weak echo areas,mid-level echo overhang and leaped vertically integrated liquid(VIL),etc..Compared with the‘4·9’convective event,the‘3·4’convective event exhibited more obvious bow echo characteristics and multiple mesocyclones when thunderstorms,gales and hail occurred.During the‘4·9’process,wind shear was weak on the incomplete multiple-cell band echo when strong wind appeared,and the convection was not as organized as the former.Therefore,the‘3·4’process had much stronger convection intensity and much wider range of influence.

关 键 词：前倾槽 飑线 环境条件 对比分析 超级单体 

分 类 号：P457.9[天文地球—大气科学及气象学]