呼伦贝尔市一次短时强降水特征分析

Analysis of A Severe Short-term Precipitation in Hulun Buir City

为了研究呼伦贝尔市短时强降水特征,防范短时强降水引发的洪涝灾害对农业产生的影响,利用地面逐时加密观测资料、NCEP再分析资料和卫星云图资料,对2009年7月12日呼伦贝尔市出现局地短时强降水天气成因进行分析。结果表明:前倾槽结构为此次短时强降水提供了非常有利的大尺度环境。短时强降水发生在低层暖湿切变线辐合区与高空弱脊辐散区相叠置区域,MCC发展阶段的入流边界。短时强降水落区具有低层高温高湿强对流不稳定层结,强的垂直风切变,强烈上升运动,并伴有螺旋度正值区的特征,中高层干冷空气入侵触发了不稳定能量释放,产生此次短时强降水天气。

In order to study the characteristics of severe short-term precipitation in Hunlun Buir and to guard against the impact on agriculture from flood disasters caused by severe short- term precipitation, using automatic meteorogical observing data, NCEP reanalysis data and satellite images, the causes of a severe short-term precipitation occurred in Hulun Buir on 12 July 2009 were preliminarily studied. The results showed that：upper forward trough provided favorable large scale condition for the severe short- term precipitation, itoccurred on coincidence area between the convergence by warm shear line in low level and the divergence byweak ridge in high level, appeared inflow boundary of the development stage of MCC. The atmosphere featureof the severe short-term precipitation exhibited strong convective instability of higher humidity and higher temperature in low level, strengthen vertical wind shear, ascending motion and positive helicity. The convectiveinstability was released by the invasion of dry air in the middle troposphere, that caused the severe short-term precipitation.