Page 96 - 《高原气象》2022年第5期

5 期 王 钦等：四川盆地两类区域持续性暴雨的环流物理量场特征及成因分析 1189

Analysis of Circulations and Physical Variables in Multi-levels Associated

with two Types of Regional Persistent Heavy Rainfall Events

1
WANG Qin ，ZENG Bo 2
（1. Civil Aviation Flight University of China，Guanghan 618307，Sichuan，China；
2. Institute of Plateau Meteorology，China Meteorological Administration，Chengdu/ Heavy Rain and Drought-Flood
Disasters in Plateau and Basin Key Laboratory of Sichuan Province，Chengdu 610072，Sichuan，China）

Abstract：Based on the precipitation data of meteorological stations in Sichuan Basin from 1961 to 2015 provid‐
ed by Sichuan Meteorological Bureau and daily reanalysis data provided by NCEP / NCAR，the differences of
large-scale circulations，source and transportation of water vapor，and physical environment conditions between
regional persistent heavy rainfall events（RPHRs）in western and eastern Sichuan Basin in recent 55 years are an‐
alyzed. The results show that：（1）during the western basin events，the longitudinal development of the troughs
and ridges in the mid-high latitudes are not as strong as that in eastern basin events. The Balkeshi Lake trough is
located more west and north with the evolution of more stable and less moving，and then there are short-wave
troughs splitting from it and moving southward to influence the western basin. However，the situation is quite dif‐
ferent in the eastern basin events. As the Balkeshi Lake trough moves southeastward，it split into two troughs af‐
ter entering China，so that the trough moved eastward along the Gansu and Shanxi provinces，and then devel‐
oped in a southeastward direction to influence the eastern basin of Sichuan.（2）Compared with the eastern basin
events，the South Asia high（SAH），the West Pacific subtropical high（WPSH），the high and low-level jet
stream and the low-level cyclonic shear are located more northwest during the west basin events，and the intensi‐
ty of these systems are relatively weaker. As the regions west of 130°E，the WPSH elongated meridionally in the
western basin type，but in the eastern basin type，it is banded zonally. What’s more，the high level jet stream
slopes southeastward.（3）Affected by the large-scale circulations，the dynamic characteristics of the upward
movement along with low-level convergence and high-level divergence are more west in western basin events.
The water vapor required by persistent rainstorms is mainly from Bay of Bengal and transported by the southwest
airflow in western basin events，while that is from South China Sea and by southeast airflow in the eastern basin
events，with stronger convective instability energy.（4）Compared with the climatological mean，there is a stable
and less active "anticyclone-cyclone-anticyclone" circulation anomaly from the Lake Balkesh to Eastern China in
the western basin events，while in the eastern basin events，the circulation anomaly shows a pattern of "anticy‐
clone-cyclone-anticyclone-cyclone"，and during the rainstorm，the pattern developed in southwestward direction
which is closely related to the more eastward and southward propagation of Rossby wave.
Key words：Sichuan Bsian；regional persistent heavy rainfall；WPSH；Rossby wave