夏季东天山中段一次强对流天气过程的数值模拟  

A numerical study of the severe convective precipitation processes over the middle section of the eastern Tianshan Mountains during the summer seasons

作　　者：连钰 杨军[1] 朱莉莉[1] 申双和[3] 李梦婕[3] 

机构地区：[1]南京信息工程大学中国气象局气溶胶与云降水重点开放实验室,江苏南京210044 [2]云南省气象台,云南昆明650034 [3]南京信息工程大学应用气象学院,江苏南京210044

出　　处：《大气科学学报》2017年第5期663-674,共12页Transactions of Atmospheric Sciences

基　　金：国家科技支撑计划项目(2012BAC23B01)

摘　　要：利用常规气象观测资料、区域自动站观测资料和FY-2D卫星逐时TBB资料,采用WRF中尺度数值模式,对2011年夏季发生在东天山中段一次强对流天气过程进行数值模拟和诊断分析,研究了天山特殊地形对降水过程的动力结构、水汽输送和云降水微物理机制的影响。结果表明,西风气流东移时受东天山的阻挡,气流从东天山南北两侧绕流,北侧急流经博尔塔拉谷地越过北天山西段后,急流右侧气流反气旋转向形成北支气流;南侧急流遇吐鲁番地区反气旋系统阻挡而转向北进形成南支气流。两支气流受地形动力抬升在东天山中段北坡汇合,为此区域局地强对流降水的形成和发展提供动力条件,北支气流为主要的水汽供应源。高空西南气流引导的冰相云系与低层局地对流云在东天山中段北坡结合,分别持续提供冰晶和云水,促使云微物理过程发展旺盛,致使局地暴雨过程产生。The Tianshan Mountains are the largest set of mountain range in middle Asia. As such,as a result of their extended zonal topography,they partially determine the distribution of the water resources in Xinjiang during the summer months,due to their capability of stimulating precipitation events. The precipitation events which are induced by the Tianshan Mountains' topography have significant benefits for the arid and sub-arid regions near Xinjiang. In this research,the aim was to explore the dynamical structures,transportation of water vapor,and microphysical mechanisms which are affected by the Tianshan Mountains' topography. A severe convective rainfall event which occurred during the summer of 2011 over the middle section of the eastern Tianshan Mountains was analyzed using the available data from ordinary observations,and automatic weather stations,along with Fengyun-2 D( FY-2 D) Temperature of Black Body( TBB) measurements. A Weather Research and Forecast( WRF)model with a nested domain setting was also employed in this study. When compared with the observational and satellite data,the WRF output was found to be nested in three sub-domains which had different spatial resolutions,and together,these data were found to reasonably recapture this particular precipitation event. Therefore,a more detailed analysis of the large-scale dynamics and microphysics was conducted in this study,in order to retrieve the features of this topographical-induced precipitation event over the middle section of the eastern Tianshan Mountains. The results showed that the eastern Tianshan Mountains had blocked one airflowmoving towards the east,and split the flowgoing around the eastern Tianshan Mountains from the northern and southern slopes. On the level of 900 to 800 h Pa,a northern jet stream converged following the Yili Valley,and then turned toward the southwest,before climbing Mount Poluokenu,which has a relatively lowaltitude in the west section of the northern Tianshan Mountains. Therefore,the northern sub-flowwas determined t

关 键 词：强对流降水 WRF中尺度模式 数值模拟 云降水微物理机制 

分 类 号：P458[天文地球—大气科学及气象学]