doi:  10.3878/j.issn.1006-9895.1909.18170

Diagnostic Analysis of A Severe Regional Snowstorm Event in the Early Winter of 2016 in Henan Province, China
摘要点击 193  全文点击 179  投稿时间:2018-06-06  
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基金:  中国气象局预报员专项CMAYBY2017-043、CMAYBY2016-042,国家重点研发计划项目 2017YFCO212400 中国气象局预报员专项CMAYBY2017-043、CMAYBY2016-042,国家重点研发计划项目2017YFCO212400
中文关键词:  暴雪  “冷空气楔”  锋生  湿位涡  对称不稳定
英文关键词:  Snowstorm  “Cold air wedge”  Frontogenesis  Moist potential vorticity  Symmetric instability
冯丽莎FENG Lisha中国人民解放军61741部队
宋攀SONG Pan中国人民解放军96941部队
郑飞ZHENG Fei中国科学院大气物理研究所
贺哲HE Zhe河南省气象台
孔海江KONG Haijiang河南省气象台
Citation:FENG Lisha,SONG Pan,ZHENG Fei,HE Zhe,KONG Haijiang.2020.Diagnostic Analysis of A Severe Regional Snowstorm Event in the Early Winter of 2016 in Henan Province, China[J].Chinese Journal of Atmospheric Sciences (in Chinese),44(1):13-26,doi:10.3878/j.issn.1006-9895.1909.18170.
      针对2016年初冬河南省首场区域强暴雪过程,利用常规观测资料、L波段雷达探空资料和NCEP再分析资料等,从影响系统和物理量诊断方面深入分析其发生发展机制,结果表明:宽广的纬向型环流中不断有短波槽东移,东北冷涡深厚且维持时间较长,是暴雪发生的大尺度环流背景;中高层偏南气流,低层偏北气流的流场配置起至关重要的作用:850~925 hPa东北急流迫使暖湿空气抬升为暴雪发生提供“冷垫”的同时,与500~700 hPa西南急流形成强垂直风切变和深厚的锋生区,加强的斜升运动和锋面次级环流,对暴雪起增幅作用;700 hPa作为关键层,西南暖湿急流输送水汽的同时与冷涡后部冷空气交汇于黄淮地区形成的辐合切变线,是暴雪发生的重要动力抬升机制,其南北摆动形成了河南中西部和东南部两个降雪大值中心;暴雪区随着“冷空气楔”逐步南压时,其上层始终存在湿正压项大于零且湿斜压项小于零的湿位涡绝对值高值中心,有利于对称不稳定能量的释放和暴雪的发生。
      Based on conventional observations, L-band soundings, and NCEP reanalysis data, the key mechanisms involved in initiating and enhancing the first severe regional snowstorm of the early winter of 2016 in Henan Province, China, were diagnosed. Results showed a large-scale circulation that included a full-latitude shortwave trough and a stable cold vortex to the northeast. Southerly mid- to upper-air and northerly lower-level winds played an important role in the snowstorm. When an 850-925 hPa northeasterly jet provided a “cold cushion” by forcing warm and humid air upward, it and a 500-700 hPa southwesterly jet formed a strong vertical wind shear and a deep frontogenetic zone. This was conducive to ascension and frontal secondary circulation, which considerably enhanced the snowstorm. The warm and humid southwest 700 hPa jet was a key feature of the storm, transporting beneficial water vapor and convergence with the cold air behind the northeast cold vortex in the Huang-Huai area. This caused considerable dynamic lifting. The north-south migration of the convergent shear at 700 hPa caused two snowfall centers in midwestern and southeastern Henan. The snow zone moved with the southward migration of the “cold air wedge.” The atmosphere above the snow zone showed a positive wet barotropic term and a negative wet baroclinic term with large absolute values of both during the entire process. This was conducive to the release of symmetric unstable energy and the development of the snowstorm. The essential and significant conditions of the snowstorm are the upper-air shortwave trough, the mid-air convergent shear, the lower-level “cold cushion” and a frontogenetic zone.
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