摘要
2020-06-17午后,在贺兰山东麓出现一次飑线天气过程,宁夏中北部及内蒙古乌海市等地出现了雷电、大风和短时强降水等强对流天气.基于多普勒雷达资料、卫星云图、闪电定位仪监测数据及地面常规气象观测资料,结合地形对该次飑线过程的发生发展机制进行分析.结果表明,在飑线过境期间,地面气象要素出现剧烈变化,并伴有明显的雷暴、闪电现象.飑线经过沙湖时,湖面蒸发水汽的垂直输送促进了飑线系统的进一步发展,在沙湖附近出现的最大降水中心、闪电强中心与降水中心吻合.在该过程前期,宁夏中北部及周边地区的大气层结不稳定,且午后的近地面辐射增温进一步加剧不稳定层结,当中高纬度冷空气沿脊东移南下时,在内蒙古阿拉善盟境内与暖气团交汇,诱发飑线形成.高低空对应的温压场不对称,系统配置呈现前倾结构,低层暖平流、高层冷平流的配置以及强的垂直风切变对该次飑线的生成与发展有利.贺兰山地形和沙湖水面对该次飑线系统起到增幅和能量补充作用.飑线系统在东移过程中,由于中低层气流受贺兰山脉地形抬升,垂直运动进一步增强,促进了飑线系统的发展.从雷达回波和卫星云图演变看,飑线系统翻山后得到明显加强;在东移经过沙湖时,又得到了湖面水汽和热能补充,使飑线系统得以持续.
In the afternoon of June 17,2020,a squall line occurred over the eastern region of Helan Mountains in Ningxia,accompanied by lightning,strong wind and short-term heavy precipitation,which affected the north and middle part of Ningxia and Wuhai of Inner Mongolia.Based on the Doppler radar data,satellite cloud images and conventional meteorological observation data,combined with topographic effect analysis,the occurrence and development mechanism of the squall line process was analyzed.The results show that:Affected by squall line,the surface meteorological elements varied violently,squall line was enhanced by vertical transportation of water vapor evaporated from Shahu lake when it moves across Shahu lake,strongest precipitation center occurred near Shahu lake,and the lightning center coincided with the precipitation center.Atmospheric stratification was unstable in the early stage,unstable atmospheric stratification was enhanced by afternoon ground radiation heating,and the cold air from the middle and high latitudes intersected with the near-surface warming air in Alashan of Inner Mongolia,which triggered convection and induced the formation of squall line;The temperature and pressure field at high and low level were asymmetrical,and the weather system presented a forward tilting structure,with warm advection in lower layer and cold advection in high layer and strong vertical wind shear,which was very conducive to the occurrence and development of squall line;The topography of Helan mountain and water surface of Shahu lake strengthened uplifting and replenished energy,thus enhanced the squall line system.The squall line developed furtherly when moving across Helan mountain due to the topographic uplifting to the middle and low level airflow.From the evolution of radar echo and satellite cloud image,we can see that the squall line has been significantly strengthened after moving across Helan mountain.
作者
李伟
穆建华
洪国平
何佳
闫军
Li Wei;Mu Jianhua;Hong Guoping;He Jia;Yan Jun(Key Laboratory of Characteristic Agrometeoro1ogica1 Disaster Monitoring and Early Warning and Risk Management in Arid Regions, CMA, Yinchuan 750002, China;Wuhan Regional Climate Center, Wuhan 430074, China)
出处
《宁夏大学学报（自然科学版）》
CAS
2022年第2期208-214,共7页
Journal of Ningxia University(Natural Science Edition)
基金
国家重点研发计划基金资助项目(2018YFE0196004)
国家自然科学基金资助项目(41865008)
宁夏自然科学基金资助项目(2020AAC03470)
中国气象局旱区特色农业气象灾害监测与风险管理重点实验室开放基金资助项目(CAMF-201816)。
关键词
贺兰山东麓
飑线
前倾结构
地形抬升
eastern region of Helan mountains
squall line
forward tilting structure
topographic uplifting
