陕西榆林地区一次暴雨过程三维风场结构演变特征  

Evolution Characteristics of Three-dimensional Structure of Wind Field During a Heavy Rainfall in Yulin of Shaanxi

作　　者：黄勤 黄鑫 李亚丽 HUANG Qin;HUANG Xin;LI Yali(Key Laboratory of Eco-Environment and Meteorology for the Qinling Mountains and Loess Plateau,Xi’an 710014,China;Shaanxi Provincial Meteorological Information Center,Xi’an 710014,China)

机构地区：[1]秦岭和黄土高原生态环境气象重点实验室,陕西西安710014 [2]陕西省气象信息中心,陕西西安710014

出　　处：《干旱气象》2020年第5期747-754,共8页Journal of Arid Meteorology

基　　金：秦岭和黄土高原生态环境气象重点实验室开放研究课题基金(2019Z—6);陕西省自然科学基础研究计划项目(2020JQ—977)共同资助。

摘　　要：利用榆林和延安两部多普勒天气雷达探测资料,采用动态地球坐标下双雷达反演三维风场方法,针对2017年7月26日榆林东南部地区暴雨过程的三维风场结构演变特征进行分析。结果表明:反演的风场能够再现此次暴雨过程中偏南气流由增强到减弱变化、切变线由东北转向东南方向移动以及雷暴单体内部上升气流由增强到减弱变化。开始阶段,子洲附近地区存在低空急流,气流呈上升运动,切变线位于强回波区东北侧,降水向东北方向发展;发展阶段,偏南气流不断增强,雷暴单体内部上升气流增强,强回波伴随切变线继续向东北方向移动;最强阶段,切变线转向东南方向移动,有进一步南压之势,上升气流明显减弱,回波顶部下沉气流增强;减弱阶段,受南下冷空气影响,偏南暖湿气流减弱,偏北干冷气流占据主导,出现明显下沉气流,强回波高度降低并向东南方向逐渐消散,降水减弱。Based on Doppler radar data at Yulin and Yan’an stations,the evolution characteristics of three-dimensional wind field structure during the rainstorm process in southeastern Yulin on 26 July 2017 were analyzed by using dual-Doppler radar retrieval method in dynamic coordinate system of earth.The results show that the retrieved wind field could reproduce the change of southerly airflow from strengthening to weakening,the movement of shear line from northeast to southeast and the change of the updrafts inside thunderstorm cells from strengthening to weakening during the rainstorm process.At the beginning stage,there was the low-level jet near Zizhou area of Yulin,and the updrafts dominated over Zizhou.The shear line located in the northeast of strong echo region,and the precipitation developed to the northeast direction.At the stage of development,the southerly airflow strengthened continuously,the updrafts inside the thunderstorm cell strengthened,and the strong echo moved continuously to northeast together with the shear line.At the strongest stage of precipitation,the movement of shear line shifted to southeast,and the updraft weakened significantly,while the downdraft at the echo top strengthened.At the weakening stage,the southerly airflow weakened due to the influence of cold air sliding southward,while the northerly airflow dominated over Zizhou area,and there was obvious downdraft.The height of strong echo decreased,and it gradually dissipated to the southeast,meanwhile the precipitation weakened。

关 键 词：双多普勒雷达 暴雨过程 三维风场结构 不同阶段 

分 类 号：P412.25[天文地球—大气科学及气象学]