摘要
利用美国国家环境预报中心(NCEP)再分析资料、广西地面自动气象站、欧洲中期天气预报中心高分辨率模式(ECMWF_HR)和多普勒天气雷达等资料,探讨2021年6月16日广西防城港山区出现大暴雨的成因机制及数值模式误差。结果表明:(1)暴雨过程不缺乏水汽和能量,但大尺度环流背景弱,尤其环境场上升运动非常弱,对准确预报大暴雨量级降水提出很大挑战;(2)山区大暴雨的出现和低层西南急流、地面中尺度辐合线密切相关;(3)此次过程成因机制是在高温高湿的环境场中,近海地面西南风加大,山区早晨逐渐转为偏北风,在暴雨区域南侧形成中尺度辐合线触发初始对流,低空西南急流持续提供水汽和不稳定能量,中尺度辐合线长时间维持提供强上升运动条件,不断触发新生成中小尺度对流回波,在西南气流引导下不断经过暴雨区域形成列车效应导致大暴雨产生;(4)主客观预报均没有报出此次过程,ECMWF_HR大尺度环流形势预报略有偏差,业务中应更注重利用高时空分辨率资料,通过中尺度分析其是否存在中小尺度系统,提前发布预报预警。
Based on the data of 1° × 1° NCEP reanalysis, Guangxi surface automatic weather station,ECMWF_HR and Doppler weather radar, the causes and numerical model errors of the heavy rain on June 16 in mountain area of Fangchenggang in Guangxi were discussed and analyzed. The results show that:(1)There is no shortage of water vapor and energy in the rainstorm process, but the large-scale circulation background is weak,especially with the very weak ascending motion condition. Under the above conditions, it is very difficult to predict the magnitude of heavy rainfall;(2) and the surface mesoscale convergence line.(3)The formation mechanism of this process is that in the high-temperature and high-humidity environment field, the southwesterly wind on the offshore surface increases and the winds in the mountain area gradually turns to the northerly in the morning. A surface mesoscale convergence line is therefore formed on the south side of the rainstorm area to trigger initial convection. The low-level southwest jet continues to provide water vapor and unstable energy, and the mesoscale convergence line maintains for a long time to provide strong upward motion conditions, which continuously triggers the new generation of small and medium-scale convective echoes. Under the guidance of southwest airflow, the train effect is continuously formed through the rainstorm area, resulting in the occurrence of heavy rainstorm.(4)Both subjective and objective rainfall forecast cannot predict this process, and ECMWF_HR large-scale circulation situation forecast has a slight deviation. Therefore, forecaster should pay more attention to the use of high temporal and spatial resolution data in the operation, and analyze whether there is a small-scale or medium-scale system through the mesoscale analysis, so as to release the forecast and early warning in advance.
作者
陈绍河
蒋承志
林文桦
曾琪
彭光固
Chen Shaohe;Jiang Chengzhi;Lin Wenhua;Zeng Qi;Peng Guanggu(Fangchenggang Meteorological Bureau,Fangchenggang Guangxi 538001,China)
出处
《气象研究与应用》
2022年第3期93-97,共5页
Journal of Meteorological Research and Application
基金
防城港市科技局重点研发计划(防科AB21014037)
广西气象科研计划面上项目(桂气科2021M09)
广西台风与海洋预报服务创新团队项目。
关键词
十万大山山区
大暴雨
成因机制
模式误差
shiwandashan mountain
severe rainstorm
genetic mechanism
model error
