2010年6月初广西一次极端暴雨特征分析

Analysis on the Characteristics of An Extreme Rainstorm in Guangxi in Early June 2010

利用NCEP1°×1°再分析资料、常规观测资料、自动雨量站加密资料及卫星资料,对2010年6月初广西来宾、都安极端暴雨过程的环流背景和中尺度系统进行了分析。结果表明,此次暴雨过程前无急流建立,850 hPa2支气流在暴雨前明显加强。过程中副高北抬,利于降水系统长时间停留在桂中桂北一带。特大暴雨区位于广西θse线相对密集区及拐点上,具备了高温高湿的不稳定条件。强降水发生在云顶亮温TBB低值中心及TBB等值线密集区,且常发生在不断激发出的中β、γ云团中,小时雨量与TBB分布有较好的对应关系。

By using NECP 1°×1° reanalysis data,conventional observation data,encrypted data of auto rainfall station and satellite data,the circulation background and mesoscale system of an extreme rainstorm in Laibin and Du＇an of Guangxi in early June 2010 were analyzed.As indicated by the results,before the rainstorm,the lower level jet was not formed,but two air currents at 850hPa intensified obviously.During the rainfall process,subtropical high stretched northward,which helped the precipitation system stay long over Central and Northern Guangxi Province.The area of heavy rain lied in the relative dense field and inflexion point of θse,which had unstable high temperature and high humidity.Heavy rain occurred in the low value area of TBB field and the intensive area of TBB isograms,as well as in the continuously excitated β and γ cloud cluster,hourly rainfall corresponded well with the distribution of TBB.