河南春季一次强降水过程水汽收支和微物理过程数值模拟

Numerical Simulation of Microphysical Process and Water Vapor Budget in a Spring Heavy Rainfall Process in Henan Province

利用ARPS模式对2007年3月3-4日河南一次大范围强降水过程进行了数值模拟,并在此基础上,分析了该暴雨过程的天气形势和水汽条件,计算了暴雨发生过程中选定区域内水汽输送、水汽收支和空中各相态水物质的量值大小及其转化关系。结果表明:这次强降水主要是受850 hPa西南涡和地面江淮气旋影响;水汽来自孟加拉湾和南海;计算区域上空的水汽收支、中低层水汽的垂直输送与地面雨强的变化有很好的对应关系,中、低层持续的较强西南暖湿气流水汽输送和明显的水汽辐合是导致河南这次强降水的重要条件。数值模拟结果显示,降水发展不同时段,云内微观结构、各种湿物质之间的转化关系和雨水形成机制都存在明显差异。

A wide range heavy rainfall process on 3-4 March 2007 in Henan province was simulated by ARPS numerical model.On the basis of accurate simulation results,the weather situation and vapor conditions was analyzed.At the same time,the author calculated water vapor transportation,water vapor budget,the concentration and transformation of each phase water during the rainfall process.The results indicated that Southwest Vortex at 850 hPa and surface Jianghuai cyclone were the main influence system.The vapor comes from Bengal Bay and South China Sea.The water vapor budget,the vertical transportation of vapor on middle and low levels correspond well with rainfall intensity.The sustained strong transportation of southwest warm wet air and the significant convergence were important condition caused this heavy rainfall process.The numerical simulation indicated the microstructure in cloud,transformation of each phase water and formation mechanisms of rain in different periods were of significant differences.