一次冷涡背景下次天气尺度系统对强对流环境场的影响  

Effect of sub-synoptic scale system on environment field of strongconvection under the background of a cold vortex

作　　者：李瑞萍[1] 王秀明[2] 李树文 王扬[3] 田晓婷 李梦军[1] LI Ruiping;WANG Xiuming;LI Shuwen;WANG Yang;TIAN Xiaoting;LI Mengjun(Taiyuan Meteorological Bureau,Taiyuan 030002,China;China Meteorological Administration Training Center,Beijing 100081,China;Shanxi Meteorological Observatory,Taiyuan 030006,China)

机构地区：[1]太原市气象局,山西太原030002 [2]中国气象局气象干部培训学院,北京100081 [3]山西省气象台,山西太原030006

出　　处：《海洋气象学报》2024年第1期76-87,共12页Journal of Marine Meteorology

基　　金：国家自然科学基金项目(41875058);中国气象局创新发展专项(CXFZ2021Z034);中国气象局复盘总结专项(FPZJ2023-018)。

摘　　要：在同一东北冷涡背景下,2016年6月12—13日山西境内连续2 d出现强对流天气,12日为分散性对流而13日为大范围强对流。基于多源资料通过对比探讨次天气尺度系统及其演变对风暴环境进而对风暴结构的影响,得出以下结论:(1)两日风暴强度和风暴结构差异显著。6月12日对流孤立分散且回波强度小于55 dBZ,而13日准线性风暴发展成尺度较大的弓形回波引发大范围强对流天气,回波强度达60 dBZ。(2)此次过程的关键影响系统为冷涡背景下的次天气尺度低涡。12日次天气尺度低压扰动开始出现,距离远而未影响山西;13日低压扰动东移发展为次天气尺度切断低涡,低涡相关的地面冷锋及850 hPa切变线触发山西上游对流。(3)12日低层水汽含量低,0~3 km垂直风切变弱,13日低涡前偏南水汽输送使低层显著增湿,叠加中层干冷空气形成不稳定层结,受低涡影响0~3 km风垂直切变增强至5.0×10-3s-1,冷锋触发的对流风暴在上述环境下强烈发展并产生阵风锋,阵风锋组织风暴形成飑线,冷池与0~3 km风切变相互作用使飑线维持。(4)13日有利于飑线发展的环境要素与东北冷涡西侧的次天气尺度切断低涡系统密切相关,次天气尺度低涡是飑线形成发展的关键系统。Under the background of a same northeast cold vortex circulation,strong convective weather occurs in Shanxi for two consecutive days from 12 to 13 June 2016.On 12,it is a scattered convection,while it is a large-scale strong convection on 13.Based on multi-source data,the effects of the sub-synoptic scale system and its evolution on the environment and then on the structure of the storms are discussed through comparison.The results are as follows.(1)There are significant differences in the intensity and the structure between the two days’storms.On 12,the convection is isolated and dispersed,and the echo intensity is less than 55 dBZ;while on 13,the strong convection is triggered by a quasi-linear convective storm that develops into a larger-scale bow echo,with the central echo intensity of 60 dBZ.(2)The key synoptic system of the process is the sub-synoptic scale vortex under the background of a cold vortex.On 12,the sub-synoptic scale low pressure disturbance begins to appear far away from Shanxi and does not have an effect there;on 13,it moves eastward and develops into a sub-synoptic scale cutoff vortex,and the surface cold front and 850-hPa shear line related to the vortex trigger the convection in the upper reaches of Shanxi.(3)On 12,the low-level specific humidity is low,and the vertical wind shear at 0-3 km is weak.On 13,the southerly water vapor transport in front of the vortex significantly humidifies the low layer,and with the superimposition of the dry cold air in the middle layer,an unstable stratification is formed.Under the influence of the vortex,the vertical wind shear at 0-3 km increases to 5.0×10-3 s-1.The convective storms triggered by the low-level cold front develop strongly and produce a gust front in the above environment,and the gust front drives the storms to form a squall line.The interaction between the cold pool and the wind shear at 0-3 km maintains the squall line.(4)The environmental factors conducive to the development of the squall line on 13 are closely related to the sub-syno

关 键 词：高空冷涡 次天气尺度系统 强对流 环境场 

分 类 号：P445[天文地球—大气科学及气象学]