川西西南涡加密探空资料分析及数值模拟试验

Analysis of the Sounding Data of Intensive Observation of the Southwest Vortex in Western Sichuan Area and Its Application in the Numerical Simulations

本文利用2010年夏,在名山、九龙、稻城三地进行的西南涡加密观测试验所取得的探空资料对川西地区的大气要素场的日变化特征进行分析,认为:3个测站的大气各个要素场的日变化特征明显,整层的风都具有日变化特征,边界层内风场的日变化更为规律一些,能观测到明显的夜间大风速带。温度和湿度场主要受下垫面影响,日变化特征只在边界层内体现。名山平均的边界层高度约为800hPa,九龙和稻城平均的边界层高度约为500hPa。3个测站相比而言,名山站的日变化幅度最小,而九龙站最为突出。将加密的探空资料引入AREM模式中,可以看到在有西南低涡存在的情况下,增加3个探空站资料后形成的初始场更有利于降水天气的产生。但主导整个模拟结果的因素还是模式系统本身,它对模拟结果产生效力主要在前24小时,其后的影响非常微弱。

Based on the sounding data obtained from the intensive observation experiments of the Southwest Vortex in the three stations of Mingshan,Jiulong and Daocheng during the summer in 2010,the diurnal characteristics of the atmospheric variables in the Western Sichuan area are analyzed in this study.The diurnal changes of the atmospheric variables are observed in these stations.The winds show a significant diurnal change in all levels,particularly in the boundary layer where the nocturnal large wind speed belt can be observed.The diurnal changes of the temperature and humidity are confined in the boundary layer,which is because these two variables are mainly influenced by the surface.The amplitude of diurnal changes are linked with the upper limit of boundary layer,the changes in Mingshan station is smaller with a boundary layer up to 800hpa,while the Jiulong station has the largest diurnal changes where the boundary layer reaches up to 500hpa. The intensive sounding data are then introduced into the AREM model.Simulations show that including the sounding date of these three stations favors the occurrence of precipitation.However,the simulations are strongly tied to the weather systems in the model.The impact of the initial state are limited in the first 24 hours and become very weak thereafter.