四川盆地西部连续两次特大暴雨过程的西南涡特征分析  

Characteristics of Southwest Vortex during Two Consecutive Heavy Rains in Western Sichuan Basin

作　　者：周春花 肖递祥[2] 陈朝平[2] ZHOU Chunhua;XIAO Dixiang;CHEN Zhaoping(Sichuan Meteorological Disaster Prevention Technology Centre,Chengdu 610072,China;Sichuan Provincial Meteorological Observatory,Chengdu 610072,China)

机构地区：[1]四川省气象灾害防御技术中心,成都610072 [2]四川省气象台,成都610072

出　　处：《高原山地气象研究》2023年第1期26-33,共8页Plateau and Mountain Meteorology Research

基　　金：四川省气象局“四川智能网格预报”创新团队项目;气象预报业务关键技术发展专项(YBGJXM(2020)2A-14);高原与盆地暴雨旱涝灾害四川省重点实验室重大专项(SCQXKJZD202101)。

摘　　要：针对两次四川盆地西部特大暴雨过程中西南涡发展与演变特征,利用欧洲中心ERA5逐小时再分析资料和FY4A卫星云顶相当黑体温度资料进行诊断分析。结果表明:两次过程的西南涡均生成于低槽东移和副高西伸的有利环流背景下。过程一的西南涡在高能高湿的环境下生成和发展,低层的感热和潜热加热作用更为显著,正涡度随高度向西倾斜发展且高度达到400 hPa,涡度拉伸项和扭转项对西南涡的发展起主要作用。过程二的偏南气流更为强盛,对流层高层的辐散抽吸作用更强,热力条件弱于过程一,西南涡范围内为高湿状态,对流层高层强的感热和凝结潜热加热使得高层增温,从而增强西南涡的发展,其正涡度发展至对流层顶,正涡度柱随高度垂直延伸,动力作用强于过程一,涡度拉伸项、扭转项和垂直输送项对西南涡的发展起主要作用。Aiming at the development and evolution of the southwest vortex during two heavy rainstorms in western Sichuan Basin,the hourly reanalysis data of ERA5 data from the European Centre and the TBB data of FY4A were used for diagnostic analysis.The following conclusions are obtained:The southwest vortex of the two processes was generated under the favorable circulation background of the eastward movement of the Trough and westward extension of the subtropical high.In the first process,the southwest vortex was generated and developed in a high-energy and high-humidity environment,and the sensible and latent heat heating effects in the lower layers were more significant.The positive vorticity developed westwards with height and reached 400 hPa.The vorticity extension and torsion terms played a major role in the development of the southwest vortex.In process 2,the southerly airflow was stronger,and the divergent pumping effect in the upper troposphere was stronger.The thermal condition was weaker than that in process 1,and the southwest vortex was in a high humidity state,The strong sensible heat and latent heat of condensation heating in the upper troposphere warmed the upper layer,thereby enhancing the development of the southwest vortex.The positive vorticity of the southwest vortex developed to the tropopause,and the positive vorticity column developed vertically with height,The dynamic effect was stronger than that of process 1,and the vorticity stretching term,torsion term and vertical transport term played a major role in the development of the southwest vortex.

关 键 词：西南涡 正涡度 特大暴雨 视热源 视水汽汇 

分 类 号：P426.6[天文地球—大气科学及气象学] P447