Page 127 - 《高原气象》2026年第2期

2 期 魏娟娟等：中亚低涡背景下北疆对流性暴雨触发与维持机制研究 427

Research on the Triggering and Maintenance Mechanisms of Convective

Heavy Rainfall in Northern Xinjiang under the Background
of the Central Asian Vortex

WEI Juanjuan ， LIU Jia ， PAN Ning ， WAN Yu 1
1
2
1
（1. Xinjiang Meteorological Observatory， Urumqi 830002， Xinjiang， China；
2. Meteorological Center of Xinjiang Air Traffic Management Bureau， Civil Aviation Administration
of China， Urumqi 830016， Xingjiang， China）

Abstract： To solve the difficult problem of forecasting the location and time of heavy rain under the background
of Central Asian low vortex. using conventional observation data， satellite， radar and ERA5 0. 25°×0. 25° reanal‐
ysis data， to analyze the mesoscale characteristics and atmospheric instability， and reveal the convection trigger‐
ing and maintenance mechanisms from June 30 to July 3， 2024， and find that there are two rainstorm centers in
this weather event， whose triggering mechanisms are significantly different. The rainstorm in Bozhou is a short-
term heavy rainfall caused by strong convection. It is affected by the eastward movement of short-wave distur‐
bances split from the bottom of the Central Asian trough， the northward movement of warm moist air carried by
southwest winds in the middle layer， and the eastward infiltration of cold air guided by east winds in the lower
layer. Warm moist air climbs along the cold cushion， and there is a convectively unstable layer in the upper air of
Bozhou. Surface mesoscale convergence lines are the main triggering factors， and middle γ scale convective sys‐
tems continue to generate and merge to enhance middle β scale convective systems to produce heavy rainfall，
and the convection has a high-quality heart structure. The rainstorm of Tianshan Mountain area and its northern
slope are characterized by mixed rainfall， with long-lasting precipitation. The Central Asian trough weakens and
moves eastward， while the southwest airflow at the middle level guides warm and humid air northward. At the
same time， the northwest jet stream at the lower level brings cold air southward， leading to the convergence of
cold and warm air. Before and in the early stages of precipitation， the atmosphere is affected by convective insta‐
bility， which accumulates unstable energy for the generation of precipitation. In the later stages， the atmosphere
shifts to conditional symmetric instability， which maintains and enhances precipitation. The frontogenesis of cold
fronts in the middle and lower layers of the troposphere is the main triggering factor of heavy rainfall. The up‐
ward movement of the secondary circulation of the front and the occurrence and development of convection are
closely related， and the front disturbance and cumulus convection have a positive feedback effect. Multiple medi‐
um β scale convection systems move eastward one after another to produce heavy rainfall， and the convection
has a low quality center and is warm cloud precipitation. This study reveals the triggering and maintenance mech‐
anisms of short-term severe convective rainstorms and mixed rainstorms in northern Xinjiang under the back‐
ground of the Central Asian low vortex by refining their types， providing key references for the refined forecast‐
ing of rainstorms in northern Xinjiang.
Key words： rainstorm； mesoscale characteristic； atmospheric instability； triggering and maintenance mecha‐
nisms； Northern Xinjiang