2017年青海东部两次强对流天气过程对比分析

TIAN Cheng-juan，ZHANG Ning-jin，MEI Cheng-hong，LIU Xue-mei，XIE Tian-rong （Qinghai Meteorological Observatory，Xining 810001，China）
Abstract：Based on conventional observation data，NCEP 1° ×1° reanalysis data，two severe convective weather processes occurred in eastern Qinghai province from July 23 to 24，2017 （referred to as“7.23”）and from July 31 to August 1，2017（referred to as “7.31”）were analyzed，and the characteristics of upper and lower environment field，dynamic，water vapor，thermal and convective instability conditions were compared. The results showed that the two severe convective weather processe occurred under the favorable background of large-scale circulation，and the main cause was that the surface cold air diffused southward from the Hexi Corridor and interacted with the southwest warm and humid air in the eastern part of Qinghai. The processes were triggered by dry tongue at 500 hPa，surface dew-point line，convergence line and surface cold front. Both processes were typical configurations of upper level diver⁃ gence and lower level convergence，“7.31”was dominated by oblique ascending movement，and the water vapor convergence in the lower layer of“7.23”was stronger than that of“7.31”. There were two water vapor belts in the two processes，one was the water vapor belt carried by the southeast airflow on the west side of the subtropical high，and the other was the water vapor belt carried by the cold air in front of the upper trough. There was a high-value center of 350 K θse near 500 hPa，and a tilted intensive belt of θse near 38°N. This frontogenesis zone was more conducive to the development and maintenance of short-term heavy precipitation. Key words：severe convective weather；temperature-humidity characteristic；unstable stratification；comparative analysis；Eastern Qinghai
热力和不稳定条件。结果表明，两次强对流天气都发生在有利的大尺度环流背景下，主要成因是地面冷
空气从河西走廊扩散南下，与西南暖湿气流在青海东部交汇；触发机制是 500 hPa 干舌、地面干线，地面
辐合线，地面冷锋；两次过程都是高层辐散，低层辐合的典型配置，“7.31”以倾斜上升运动为主，“7.23”低
层水汽辐合强于“7.31”；两次过程都有两条水汽带，一条为副热带高压西侧的东南气流输送水汽带，另
DOI:10.14088/ki.issn0439-8114.2021.17.011
开放科学（资源服务）标识码（OSID）：
Comparison and analysis of two severe convective weather processes in eastern Qinghai in 2017
2017 年青海东部两次强对流天气过程对比分析
田成娟，张宁瑾，梅成红，刘雪梅，谢天蓉
（青海省气象台，西宁 810001）
摘要：利用常规观测资料、NCEP1°×1°再分析资料，分析在青海省东部 2017 年 7 月 23—24 日和 2017 年 7
月 31 至 8 月 1 日发生的两次强对流天气过程（简称“7.23”和“7.31”），对比分析高低空环境场特征、动力、
第 60 卷第 17 期 2021 年 9 月
湖北农业科学 湖Hub北eio.17 S2e0p2.1，2年021
田成娟，张宁瑾，梅成红，等 . 2017 年青海东部两次强对流天气过程对比分析［J］. 湖北农业科学，2021，60（17）：54-58 ．
一条为高空槽前冷空气携带水汽带；500 hPa 附近有 350 K 假相当位温（θse）高值中心，38°N 附近有倾斜
的 θse 等值线密集带，这种锋生带更有利于短时强降水发展和维持。
关键词：强对流天气；温湿特征；层结不稳定；对比分析；青海东部
中图分类号：P463，P461
文献标识码：A
文章编号：0439-8114（2021）17-0054-05