Page 167 - 《高原气象》2026年第1期

1 期 刘成瀚等：长白山南部暴雨的环流前兆和复杂地形作用研究 163
指标及其与灾情的关系研究［J］. 气象与环境科学， 44（5）： 33- Rainstorm Process and its Relationship with Disasters in Sichuan
39. DOI： 10. 16765/j. cnki. 1673-7148. 2021. 05. 005. Zhou B， Basin［J］. Meteorological and Environmental Sciences， 44（5）：
Wang C X， Zhang S Q， et al， 2021. Similarity Index of Regional 33-39. DOI： 10. 16765/j. cnki. 1673-7148. 2021. 05. 005.

Study on Circulation Precursors and Complex Topographic Effects of

the torrential rain events in the South of Changbai Mountains

LIU Chenghan 1， 2， 3， 4 ， LU Jinglong ， YAN Qi ， WANG Yue ， JIAO Haoran ， Jin Yan 6
4， 5
2
2， 3
2， 3
（1. China Meteorological Administration Hydro-Meteorology Key Laboratory， Beijing 100081， China；
2. Liaoning Meteorological Observatory， Shenyang 110166， Liaoning， China；
3. Institute of Atmosphere Environment， China Meteorological Administration， Shenyang 110166， Liaoning， China；
4. Panjin National Climate Observatory， Panjin 124000， Liaoning， China；
5. Shenyang District Meteorological Bureau， Shenyang 110166， Liaoning， China；
6. Shanghai Meteorological Center， Shanghai 200030， China）

Abstract： Based on the observed precipitation data from 2010 to 2019 in the complex terrain region of southeast‐
ern Liaoning， this study identified 44 torrential rain events （TRECT）. By employing composite analysis methods
and decomposing the lower-level wind field using flow-over and flow-around equations， the circulation precur‐
sors， common characteristics of circulation fields， and the dynamic impact mechanism·s of topography on re‐
gional torrential rain were systematically investigated. The results indicate that： Six days prior to the occurrence
of TRECT events， the mid-troposphere over the Eurasian continent exhibited a blocking high pattern， followed
by the eastward movement and development of a shallow trough near Lake Baikal. On the day of the event， the
subtropical high moved northward and intensified， forming a slanting trough over the western part of the key ar‐
ea， with a closed cyclonic circulation appearing in the lower troposphere. The North China low-pressure system
developed and moved eastward， positioning the key area at the top of the inverted trough， providing a favorable
circulation background for widespread precipitation. During the peak period of the event， the flow over and
around the terrain in the key area showed stronger southern and weaker northern characteristics， with high-value
areas concentrated in the trumpet-shaped terrain region of the Changbai Mountain's foothills. Areas with flow-
over speeds exceeding 4 m⋅s were located on the southern slopes of the low-altitude hills in the trumpet-shaped
-1
area， while flow-around was observed around the high-altitude mountains， with meridional branches of both
flows playing a dominant role. The flow-over and flow-around entered the trumpet-shaped area by crossing and
bypassing the mountains， respectively， primarily from two air stream·s originating from the Yellow Sea and the
Korean Peninsula. In the trumpet-shaped area， the upward motion contributed by the flow-over accounted for
more than 80% of the total system's upward motion， serving as the main dynamic source for precipitation en‐
hancement. The flow-around， under the influence of topography， formed local positive vorticity， further enhanc‐
ing the dynamic conditions for precipitation. This study systematically investigates the evolutionary characteris‐
tics of precursor large-scale circulation system·s associated with torrential rain events in the complex topography
of the Changbai Mountain foothills， exploring atmospheric circulation precursors preceding extreme precipita‐
tion. Through mesoscale topographic dynamic forcing mechanism·s， it specifically elucidates the orographic lift‐
ing-convergence effect and flow-around vorticity development within the trumpet-shaped terrain of southeastern
Liaoning Province. It provides a theoretical basis for improving the accuracy of regional mountain type rainstorm
forecast.
Key words： complex topographic； torrential rain； circulation precursors； flow over； flow around