山东初冬一次极端降水和大风天气成因分析  

Causes of an Extremely Precipitation and Gale in Shandong Province in Early Winter

作　　者：李博 王玮 刘飞 景安华 郭文明 LI Bo;WANG Wei;LIU Fei;JING Anhua;GUO Wenming(Heze Meteorological Bureau,Heze 274000,China;No.91937 Army of PLA,Zhoushan 316000,China;No.91876 Army of PLA,Qinhuangdao 066000,China)

机构地区：[1]菏泽市气象局,山东菏泽274000 [2]91937部队,浙江舟山316000 [3]91876部队,河北秦皇岛066000

出　　处：《沙漠与绿洲气象》2023年第4期30-37,共8页Desert and Oasis Meteorology

基　　金：山东省气象局面上项目(2018sdqxm01);菏泽市气象局面上项目(2020006)。

摘　　要：利用常规地面、高空观测、雷达及ERA5再分析等资料,对2021年11月6—7日山东初冬一次极端降水、大风天气成因分析,结果表明:低槽东移发展,冷空气南压,低空切变线配合东北、西北地区地面高压坝形成的“阻挡”形势利于极端降水的产生。本次过程水汽条件具有较强的极端性,水汽通量辐合远强于气候平均态,925和700 hPa水汽通量辐合大值区与雨、雪区域配合较好。冷锋过境条件对称不稳定触发产生对流,随后在冷锋后侧逆温层上由锋生过程的上升支环流强迫产生高架对流。强冷空气扰动从内蒙古高原下滑至华北平原,与近地面冷平流汇合增强,产生较强变压风,同时促进了势能向动能转换及动量下传。地形强迫造成下沉运动增强,华北地区低层形成锋面次级环流,环流前部锋区暖界面为地转偏差辐合,冷界面为地转偏差辐散。环流内有水平动能和地转偏差大值区,偏北气流和下沉运动使水平动能向南、向下输送,导致地面极端大风。Based on conventional ground and upper air observation data,radar data,and ERA5reanalysis data,this study analyzes the causes of an extreme precipitation and gale in early winter in Shandong.The results reveal that the eastward movement of a low trough,the southward press of cold air,and the“blocking”situation formed by the low altitude shear line in coordination with the highpressure dam in the northeast and northwest of the ground contribute to the occurrence of extreme precipitation.The water vapor condition in this process is characterized by extreme values,with water vapor flux convergence much stronger than the climate mean state.The moisture flux convergence regions at 925 hPa and 700 hPa correspond well with rain and snow regions,respectively.Convection is triggered by the asymmetric instability of cold front transit conditions,followed by elevated convection forced by upward-ramus circulation in the inversion layer behind the cold front.The strong cold air disturbance slips from the Inner Mongolia Plateau to the North China Plain,then converges with the cold advection and intensifies,generating stronger variable pressure wind and resulting in the conversion of potential energy to kinetic energy and momentum down.Topographic forcing enhances subsidence movement and the formation of frontal secondary circulation in the lower layer of north China.The warm interface of the front region is the convergence of geostrophic deviation,and the cold interface is the divergence of geostrophic deviation.The circulation is characterized by large values of horizontal kinetic energy and geostrophic deviation,and the northerly airflow and descending movement transport the horizontal kinetic energy southward and downward,leading to extreme surface winds.

关 键 词：暴雪 寒潮大风 高架对流 温度平流 水平动能 地转偏差 

分 类 号：P458[天文地球—大气科学及气象学]