Page 111 - 《高原气象》2023年第1期
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1 期 肖贻青等：西北涡与西南涡共同作用引发秦巴区域大暴雨的成因分析 107
周淼， 刘黎平， 王红艳， 2014. 一次高原涡和西南涡作用下强降水 周玉淑， 颜玲， 吴天贻， 等， 2019. 高原涡和西南涡影响的两次四川
的回波结构和演变分析［J］. 气象学报， 72（3）： 554-569. 暴雨过程的对比分析［J］. 大气科学， 43（4）： 813-830.
Analysis on a Heavy Rainstorm in Qinba Region Caused by
Southwest Vortex and Northwest Vortex
2， 3
1
XIAO Yiqing ， LOU Panxing ， LI Mingjuan ， WANG Jixin 4
1， 2
（1. Shaanxi Meteorological Observatory， Xi'an 710014， Shaanxi， China；
2. Key Laboratory of Eco-Environment and Meteorology， Qinling Mountains and Loess Plateau， Xi’an 710000， Shaanxi， China；
3. Shaanxi Provincial Institute of Meteorological Science， Xi’an 710016， Shaanxi， China；
4. Gansu Meteorological Observatory， Lanzhou 730020， Gansu， China）
Abstract： A heavy rainstorm in Qinba region caused by northwest vortex and southwest vortex on 3 -4 Septem‐
ber 2021 is analyzed based on conventional observational data， ERA-5 reanalysis data and FY-4A satellite data，
for discussing the mesoscale environment characteristics and process of southwest vortex. The result shows that
α-mesoscale MCC caused by northwest vortex and southwest vortex leading to the heavy rainstorm， and strong
precipitation area coincides with the cold center of the cloud black body and large gradient of TBB. Before the
formation of southwest vortex， the convergence of north wind behind northwest vortex and southwest wind
formed mesoscale shear line， triggering convective instability to form mesoscale convective clouds. Under the in‐
fluence of southwest vortex and northwest vortex， the water vapor transport， the positive vorticity， strong con‐
vergence and updraft at lower troposphere in Qinba region are significantly enhanced， together with development
of β-and γ-mesoscale convective clouds， leading to the heavy rainstorm in Qinba region. The southwest vortex is
generated by downward positive vorticity and large potential vorticity caused by low vortex at 500 hPa， leading
northerly wind behind the northwest vortex and southwest wind to form cyclonic circulation. Vertical coupling of
southwest vortex and low vortex at 500 hPa can make southwest vortex a strong system， strengthening the con‐
vergence and vertical ascend movement of water vapor to enhance precipitation.
Key words： Qinba region； Northwest vortex； Southwest vortex； heavy rainstorm； MCC； potential vorticity
