大气科学2025，Vol.49Issue(3)：664-680,17.DOI:10.3878/j.issn.1006-9895.2404.23096
四川南部一次局地暖区暴雨中尺度特征及成因
Mesoscale Characteristics and Causes of the Warm-Sector Rainstorm Process in Southern Sichuan
摘要
Abstract
Based on hourly precipitation data from automatic weather stations,hourly temperature data from multisource fusion,high-altitude observation data,meteorological satellite data from FY-4A,X-band dual polarization radar data,and ERA5 reanalysis data,the mesoscale characteristics and causes of a warm-sector rainstorm process in the Panxi area of southern Sichuan from 2000 BJT on October 4,2022,to 1200 BJT on October 5,2022 are analyzed.The results show that(1)this process manifested as a β-γ mesoscale convective system on satellite imagery,which went through three stages of developing,strengthening,and weakening in the Zemulong Village area.The mesoscale convective system of rainstorms tilts east from bottom to top,allowing the convective system to sustain itself and develop for a longer period.(2)Radar echoes in the Zemulong Village area show a strip-shaped distribution with notable back-propagation and echo training effects.The strong echo nuclei are relatively low,mostly below 4.5 km,and each nucleus weakens rapidly;thus,they exhibit a high precipitation efficiency.(3)During this process,the atmosphere is in an unstable state of the dry upper layer and moist lower layer,with a low convective condensation level,lifting condensation level,and level of free convection;thus,the air mass does not need to be lifted too strongly to move upward and cause water vapor condensation;therefore,the thunderstorm system can rapidly develop.Furthermore,weak vertical wind shear reduces the involvement of unsaturated dry cold air,weakens the entrainment rate,and improves precipitation efficiency.(4)The convergence and cyclonic flow field formed by the blocking effect of the terrain on the northwest edge of Panzhihua is the main factor for generating continuous convection and forming training effects;thus,extreme precipitation occurs in the Zemulong Village area.Meanwhile,in the Guanyintang Village,the southwest low-level jet stream is nearly orthogonal to the northeast mountains,which forces the airflow to rise and form heavy precipitation in the low-lying areas at the front of the mountain.Owing to the southwest low-level jet,the convergence of wind speeds caused by terrain and terrain circulation caused by terrain temperature gradient also promote the formation of heavy precipitation.关键词
攀西地区/暖区暴雨/中尺度特征/成因分析/地形作用Key words
Panxi area/Warm-sector rainstorm/Mesoscale characteristics/Cause analysis/Topographic effect分类
天文与地球科学引用本文复制引用
李永军,徐金波,李玄,何科,严晶,资晶,卢萍..四川南部一次局地暖区暴雨中尺度特征及成因[J].大气科学,2025,49(3):664-680,17.基金项目
高原与盆地暴雨旱涝灾害四川省重点实验室项目SCQXKJYJXMS202306,攀枝花市指导性科技计划项目2022ZD-S-6,四川省自然科学基金项目2022NSFSC0021,科技部国家重点研发计划2022YFC3003902 Heavy Rain and Drought-Flood Disasters in Plateau and Basin Key Laboratory of Sichuan Province(Grant SCQXKJYJXMS202306),Panzhihua Guiding Science and Technology Plan Project(Grant 2022ZD-S-6),Sichuan Natural Science Foundation Project of Sichuan Province(Grant 2022NSFSC0021),National Key R&D Plan of the Ministry of Science and Technology(Grant 2022YFC3003902) （Grant SCQXKJYJXMS202306）
