广元市区域暴雨天气预报研究

Research on Regional Rainstorm Forecast in Guangyuan

利用2000~2015年广元市5个国家气象观测站逐日和逐时降雨量、MICAPS资料和ERA-Interim资料,从时空分布特征、环流形势和主要影响系统、暴雨预报指标等方面对广元市暴雨天气进行了分析。结果表明:广元市暴雨空间分布特征为东多西少、南多北少,时间分布特征为7月上下旬和9月中上旬是暴雨发生的两个峰值;区域性暴雨的夜雨特征明显,03~08时是短时强降雨的高发期;低槽东移型、副高稳定型、东高西低型和两高切变型这4种500hPa西风带环流和副高分型以及700~850hPa影响系统的位置和强度差异会对暴雨落区和强度有明显影响;中低层水汽、热力和动力等物理量的变化能为预报区域性暴雨提供定量参考。

Based on the daily and hourly rainfall data,MICAPS data and ERA-Interim data of five national meteorological stations in Guangyuan City from 2000 to 2015,the rainstorm weather in Guangyuan City was analyzed from the aspects of spatial and temporal dis-tribution characteristics,circulation situation,main influence system and rainstorm forecast index.The results show that the spatial distri-bution of rainstorm in Guangyuan City is more in the east than in the west and less in the south than in the north.The time distribution characteristics are early and late July and early September are two peaks of rainstorm.The nightfall characteristics of regional rainstorms are obvious,and 03~08:00 is the high occurrence period of short-term heavy rainfall;500hPa westerly circulation and subtropical high type(low trough eastward shift type,subtropical high stable type,east high west low type and two high shear type),as well as 700~850hPa influence system position and intensity difference will have obvious influence on rainstorm area and intensity.The changes of physical quantities such as water vapor,heat and power in the middle and lower layers can provide quantitative reference for the predic-tion of regional rainstorm.