干旱区研究2025，Vol.42Issue(4)：600-612,13.DOI:10.13866/j.azr.2025.04.03
西北东部一次强降水形成机制及能量来源
Formation mechanism and energy source of a heavy rainfall event in the eastern northwest region
摘要
Abstract
This study analyzes the spatial and temporal distribution,circulation patterns,and water vapor trans-port characteristics of a heavy precipitation event in Longnan City,Gansu Province,on July 10,2020,using hour-ly precipitation observations and ERA5 reanalysis data.Additionally,atmospheric moisture energy(MSE)was in-troduced to investigate the unstable energy sources of convective activity,providing a new perspective for the re-evaluation and diagnosis of severe convective weather in the northwest region,as well as new reference indica-tors for business forecasting.The results show that:(1)The heavy precipitation exhibited high intensity,obvious locality,and strong convection.At 500 hPa,the plateau shortwave trough facilitated the convergence of cold and warm air,while at 700 hPa,the southerly airflow combined with cyclonic shear provided favorable conditions for water vapor transport and dynamic uplift.(2)The occurrence of heavy precipitation was accompanied by MSE charging and discharging.The MSE accumulates continuously before the peak of heavy precipitation,putting the atmosphere in a charging state.After peaking,the MSE significantly decreased,and the atmosphere was in a state of energy release.(3)The mechanisms of atmospheric charging differed by vertical height,with vertical MSE transport in the lower troposphere contributing positively,whereas horizontal advection contributing negatively.Horizontal advection,particularly meridional advection,positively contributed to the middle layer,whereas verti-cal transport contributed negatively.The increase in MSE transport in the upper troposphere is mainly driven by meridional advection.(4)The vertical transport of water vapor influenced the MSE in the lower troposphere,whereas the latent heat energy from water vapor controlled MSE in the middle layer.The meridional advection of water vapor increases the MSE due to abnormal southerly winds.High-level MSE is dominated by the internal en-ergy term,and the main contribution to the increase in MSE is the meridional advection caused by the combina-tion of westerly winds and temperature gradients that are warm in the west and cold in the east.关键词
强降水/大气不稳定能量/湿位能/水汽通量/西北地区Key words
heavy precipitation/atmospheric instability energy/moist potential energy/water vapor flux/Northwest China引用本文复制引用
石霞,刘维成,陈晓燕,黄玉霞,谭丹,伍继业..西北东部一次强降水形成机制及能量来源[J].干旱区研究,2025,42(4):600-612,13.基金项目
甘肃省自然科学基金项目(23JRRA1573,24JRRA1182) （23JRRA1573,24JRRA1182）
中国气象局气象能力提升联合研究专项(23NLTSZ001) （23NLTSZ001）
甘肃省气象局区域数值预报创新团队(GXQXCXTD-2024-03)共同资助 （GXQXCXTD-2024-03）
