鲁西北一次农业致灾暴雨天气成因分析

为了揭示局地暴雨天气的成因,以期为此类农业灾害性天气的预报预警提供指示,笔者利用常规观测资料、加密自动站资料和多普勒雷达回波资料,对鲁西北地区2012年7月4—5日暴雨天气过程的环流背景、物理量场特征和中小尺度系统进行分析。结果表明:此次暴雨的主要影响系统是高空西风槽、切变线和低空急流;聊城地区水汽通量散度所揭示的强水汽辐合时间与垂直运动发展增强时间没有很好的对应,因此此次强降水时间较短;暴雨落区与强上升运动的发展区域在空间上相关性更好;对流层低层辐合线触发了不稳定能量的释放产生暴雨;此次暴雨过程的局地特点可以用中小尺度系统进行解释,而中小尺度系统的跟踪一定程度上依赖于区域站资料的开发应用;多普勒雷达的强雷达回波单体和阵风锋能较好地解释此次局地暴雨过程,多普勒雷达产品的应用有待进一步深化研究。

A Rainstorm Process Which Caused Agricultural Disaster in Northwest Shandong

To reveal the causes of local rainstorm, and provide references for forecasting and early warning of agricultural disastrous weather, based on conventional observation data, encryption automatic station data and doppler radar echo data, the authors diagnosed and analyzed circulation background, physical quantity field and meso scale system of a rainstorm process from July 4 to 5, 2012 in northwestern Shandong. The results showed that: the main system of the rainstorm was the westerly trough, shear line and the low-level jet; the development of strong water vapor convergence time revealed by water vapor flux divergence in Liaocheng did not had a good relationship with enhanced vertical movement time, so the strong precipitation time was short; the spatial correlation between the precipitation area and the strong upward motion was better; the release of unstable energy triggered by convergence line in the lower troposphere produced rainstorm; the local characteristics of the rainstorm process could be explained by using small and medium scale system, the tracking of small and medium scale system was dependent on the development and application of the regional station data; the strong radar echo monomer and gust front of doppler radar could well explain the local rainstorm process, and the application of doppler radar products should be further studied.