摘要
[目的]探讨特大暴雨的形成机制,并揭示特大暴雨的成因。[方法]采用常规报文资料作为初始场,运用改进的中尺度REM模式,对2010年6月16～20日一次江西特大暴雨过程进行了数值模拟和诊断分析,研究了改进的中尺度模式对此次暴雨过程的降水模拟能力,探讨特大暴雨的形成机制,揭示特大暴雨的成因。[结果]这次特大暴雨是一次典型的梅雨暴雨,500 hPa东亚大槽槽后、700 hPa华北低涡后冷平流与强盛稳定的副高西北侧西南气流汇合,导致梅雨锋在江南北部维持;梅雨锋的稳定和西南暖湿气流的异常强盛,使暴雨的水汽、动力、热力条件十分充足,非常有利于触发中尺度对流系统强烈发展;强盛水汽输送及辐合上升运动、中层弱冷空气活动、高层强辐散等多种因素的共同影响导致了特大暴雨发生;改进的中尺度模式对降水场模拟结果与实况基本相似,模式对暴雨的位置、强度、中心均有较好的模拟;物理量分布和局地中心对暴雨预报有明显的指示意义。[结论]该研究为提高暴雨预报能力提供参考。
[Objective] The aim was to discuss the heavy rainfall formation mechanism and to reveal the causes of rainstorm.[Method] Based on the conventional ground observational data,a numerical simulation and diagnosis analysis had been carried on heavy rainfall event over Jiangxi province from 16 June to 20 June 2010,with a meso-scale REM model.The results showed that this rare rainstorm was a typical heavy rainfall over Meiyu front.The cold air flew behind the 500 hPa East Asia trough and 700 hPa North China vortex joined up the southwestern flow located in the northwest part of the strong and stable subtropical high,thus the cold air and warm air converged and maintained over the northern part of Hunan and Jiangxi province.Since the area that cold air and warm air joined up was stable and the southwestern warm and wet flow was abnormally strong,the vapor,dynamical,and thermodynamic conditions was leading to the trigger the strongly development of meso-scale convection systems.The extraordinary rainstorm was caused by the interaction of many factors such as strong vapor and convergence ascending motion,weak cold air activities in middle-levels,the strengthening of southwestern low-level jet,the formation and maintenance of southwestern vortexes,etc.The simulated precipitation of the high resolution model was very similar with the observational rainfall.The model had a good predictive skill for the location,intensity and center of heavy rainfall.By diagnosing the physical variables,it found that the distribution characteristic of the physical variables had an obvious indication for precipitation forecast.[Conclusion] The study provided reference to improve rainstorm forecast.
出处
《安徽农业科学》
CAS
2012年第33期16244-16247,共4页
Journal of Anhui Agricultural Sciences
基金
国家自然科学基金项目(41105075
40805019
40605017)
关键词
特大暴雨
数值模拟
诊断分析
江西
Heavy rainfall
Numerical simulation
Diagnosis analysis
Jiangxi Province
