摘要
利用常规气象观测数据、吉林省加密自动站观测数据、NCEP的1°×1°再分析资料和卫星云顶亮温数据,对2018年8月13—15日吉林省一次暴雨过程成因进行分析。结果表明:“三带”(西风带、副热带和热带环流)是暴雨产生的大尺度环流背景。大气整层水汽通量显示副热带高压外围的西南气流与远距离台风外围东南气流共同为暴雨输送充沛的水汽。降水有两个主要阶段,大气层结特征均为高层有正值位涡扰动并沿假相当位温锋区下滑,大气层结不稳定,水汽充沛,不稳定能量较大。降水第二阶段水汽输送、动热力条件、不稳定能量均小于第一阶段。云图表现特征为中尺度对流辐合体和中尺度对流云团,中尺度对流辐合体云团发展旺盛时,低层呈现气旋式涡度、中尺度辐合,高层呈反气旋式涡度、中尺度辐散。925 hPa低空切变线和地面辐合线是暴雨发生的中尺度触发条件。
Based on the data from the conventional meteorological and automated stations,NCEP(National Centers for Environmental Prediction)1°×1°reanalysis and satellite black body temperature,formation reasons for a continuous heavy rainfall that occurred in Jilin province on August 13-15,2018 were analyzed.The results show that"three zones"(westerly zone,subtropical zone and tropical zone circulation)are the large scale circulation backgrounds for the formation of this heavy rainfall.From the water vapor flux throughout the atmosphere,it reveals that an abundant water vapor delivering by the southwest airstream at the periphery of subtropical high and the southeast airstream at the periphery of a typhoon coming from a long distance away is supplied to the heavy rainfall zone.This heavy rainfall process can be divided into two phases.First,a positive moist potential vorticity disturbance existing at the high levels slides along the pseudo-equivalent potential temperature front zone and forms an unstable atmospheric stratification that has adequate water vapor and high unstable energy.Compared with the first phase,the water vapor and thermal conditions are weak,and unstable energy is small in the second phase.From the satellite images,it shows an MCC(Mesoscale Convective Complexes)and meso-scaleαconvective cloud.When the MCC cloud is in a thriving stage,cyclonic vorticity and meso-scale convergence exist at the low level and anticyclone vorticity and meso-scale divergence exists at the high level.The shear line at 925 hPa and convergence line at the surface are the meso-scale initiation condition for this heavy rainfall.
作者
王秀娟
姜忠宝
马晓华
冯旭
WANG Xiu-juan;JIANG Zhong-bao;MA Xiao-hua;FENG Xu(Meteorological Observatory of Jilin Province,Changchun 130062,China;Key Laboratory of Cloud-Precipitation Physics and Severe Storms of Institute of Atmospheric Physics,Chinese Academy of Sciences,Beijing 100029,China;University of Chinese Academy of Sciences,Beijing 100049,China;Climate Center of Jilin Province,Changchun 130062,China;Meteorological Observatory of Shaanxi Province,Xi′an 710044,China)
出处
《气象与环境学报》
2020年第2期1-8,共8页
Journal of Meteorology and Environment
基金
国家自然科学基金(41775166、41705142)
吉林省气象局科研项目(201709)共同资助。
关键词
整层水汽通量
假相当位温
位涡
中尺度对流辐合体
Water vapor flux throughout the atmosphere
Pseudo-equivalent potential temperature
Potential vorticity
MCC(Mesoscale Convective Complexes)
