2018年7月中旬北京市一次暴雨过程的天气学分析

Synoptic Analysis of a Rainstorm Process in Beijing in Mid-July 2018

摘要: 本文利用MICAPS系统使用全国气象站数据对2018年7月16~17日北京“7.16暴雨”事件进行了分析。通过对大尺度环流形势分析、水汽条件分析、不稳定条件分析、抬升动力条件分析以及卫星云图等的分析得出以下结论：1) 本次降雨过程暴雨范围小，局地性强，强度变化大，持续时间短。2) 环流形势上高纬低压槽提供北方干冷空气输送，西太平洋副热带高压提供南方暖湿气流和源源不断的水汽。3) 在对北京地区相对湿度场、水汽通量散度场、假相当位温场等物理场进行分析后可以观察出暴雨期间北京地区的水汽条件充足。4) 在对不稳定条件分析后K指数、SI指数和CAPE值能反应出暴雨过程中不稳定能量的堆积。5) 抬升动力条件分析可以反应出北京地区低层辐合上升，高层辐散，为降水提供良好的动力条件。6) 卫星云图显示北京地区上空存在积雨云且水汽条件充足，为暴雨提供了条件。

Abstract: This paper uses the MICAPS system to use the national weather station data to conduct a weather analysis of the “7.16 torrential rain” incident in Beijing on July 16-17, 2018. Through the large-scale circulation situation analysis, water vapor condition analysis, unstable condition analysis, lifting dynamic condition analysis and satellite cloud image analysis, the following conclusions are drawn: 1) The rainstorm range is small, the locality is strong, and the intensity is strong, the duration is short. 2) Circulation situation: The high latitude trough provides high dry and cold air transport in the north, and the western Pacific subtropical high provides warm and humid air in the south and a steady stream of water vapor. 3) After analyzing the physical field of relative humidity field, water vapor flux divergence field and false equivalent temperature field in Beijing, it can be observed that the water vapor conditions in Beijing area are sufficient during heavy rain. 4) After analyzing the unstable conditions, the K index, SI index and CAPE value can reflect the accumulation of unstable energy during heavy rain. 5) Uplifting dynamic conditions analysis can reflect the rise of low-level convergence in the Beijing area, high-level divergence, providing good dynamic conditions for precipitation. 6) The satellite cloud map shows that there are cumulonimbus clouds over the Beijing area and sufficient water vapor conditions provide conditions for heavy rain.