2018年广西东南部一次暴雨过程分析

利用Micaps高空和地面资料、新一代天气雷达、卫星云图、地面中尺度自动站观测资料及NCEP 1°×1°再分析资料,对广西东南部2018年5月10日暴雨过程的环流形势、环境场、中尺度对流系统特征及其可预报性进行分析。结果表明:此次桂东南暴雨过程的高层辐散条件不明显,但中低层环流形势有利、具有高压后部"回流"降水的典型特征。配合超低空东南气流加强,导致局地暴雨增幅明显。地面中尺度辐合线的长期稳定维持及地形抬升作用使得降水系统在陆川、博白一带不断发展和维持,雷达回波上形成"列车"效应,造成暴雨天气。全球数值模式ECMWF对天气尺度背景把握较好,GRAPES、华东模式等中尺度模式能够提供类似系统形成、发展的有价值的参考信息。通过中尺度模式产品发现暴雨天气过程前兆,及时根据最新实况观测资料和模式偏差分析对全球模式预报结论进行订正,同时注意叠加局地地形地貌特征信息辅助短时临近预报订正,是提高类似较强过程预报的可行做法。

Comprehensive Analysis of Heavy Rainfall in Southeast of Guangxi on 10 May 2018

Abstract: Based on the data of radar , satellite , surface mesoscale automatic observation and NCEP reanalysis data, this article analyzed the synoptic background characteristics , mesoscale systems and predictability of the extreme rainfall process on 10 May 2018. The results showed: During the rainstorm, the high-level divergence conditions wasn''t obvious , but the favorable?middle-low-level Circulation situation, and returning flow by High pressure rear were the typical characteristics of rainstorm; With the strengthening of the ultra-low southeasterly airstream, the local rainstorm increased significantly, The mesoscale surface wind convergence line and landform uplifting effect maked the rain system develop and maintain continuously in Luchuan and Bobai areas. the "Train" effect formed on radar Echo, caused extreme cumulative precipitation. The ?Global numerical model ECMWF has a good grasp of synoptic scale background, the Mesoscale models such as GRAPES and WARMSv2.0 can provide valuable reference information for the formation and development of systems. It is a feasible way to improve the forecast of similar strong processes by finding the early signs of rainstorm weather process through mesoscale model products, revising the forecast conclusion of global model timely based on the latest observation data and model deviation analysis, and paying attention to the short-time nowcasting correction assisted by superposition of local topographic and geomorphic feature information