山东南部一次极强降水的结构演变特征分析

为深入了解山东南部地区夏季暴雨发生机制,进一步提高预报准确率,应用常规观测资料、NCEP 1°×1°再分析资料、FY-2E逐时云顶亮温TBB资料、地面加密自动站资料及多普勒雷达资料等,对发生在山东南部地区的一次大暴雨天气过程进行详细分析。结果表明:该过程在有利的天气形势下发生;大气对流不稳定,低层有较强暖平流,中层干冷空气与低层的暖湿空气混合,使大气对流不稳定度加大;强降水出现在上下层正涡度相叠加、低层正涡度增大的过程中;暴雨中心与云顶亮温TBB的最低值中心及强度有密切关系;大暴雨期间多普勒雷达能及时捕捉到冷空气和强回波活动情况,此次强降水过程分别对应2个强降水时段。

Analysis of Structure Evolution Characteristics of a Strong Precipitation in Southern Shandong

In order to investigate the mechanism of summer rainstorm occurred in southern Shandong Province and further improve the prediction accuracy, using conventional observation data, NCEP 1°×1° reanalysis data, FY-2E satellite TBB hourly data, the intensive observations of automatic weather station data, Doppler weather radar data and so on, a rainstorm process in southeastern area of Shandong Province was analyzed in detail. The results showed that the rainstorm occurred under favorable weather condition; the process that middlelevel dry cold air mixed with low-level warm air coming from a strong low-level warm advection and increased the atmosphere convective instability. The severe precipitation was produced when the lower positive vorticity increased while the upper and lower positive vorticity were superimposed. Storm center was closely related to the minimum value of the center and the strength of TBB. Doppler radar captured the cold air and strong echo activities during the heavy rain, and the heavy rainfall corresponded to two periods of heavy precipitation.