北京"7·16"暴雨诱发地质灾害成因分析

Starting from the rainfall situation and geological disaster situation during the heavy rain process in Beijing on July 16, 2018, the meteorological early warning and verification of geological disasters in this process are introduced. And based on the information of the susceptibility degree of regional geological disasters in Beijing, combined with the multi-source fusion quantitative precipitation estimation (QPE) to drive the CREST hydrological model to simulate the runoff and soil moisture characteristics and the process rainfall intensity characteristics, the meteorological causes of this geological disaster in Beijing are analyzed. The results show that the northern and western parts of Beijing are in the medium and high susceptibility areas of geological disasters. When the hourly accumulated area rainfall in districts (counties) reaches more than 50 mm, disasters are prone to occur. The period 24 hours after the precipitation is a high-incidence period of geological disasters, and disasters often occur within 15 hours after a relatively large peak of rainfall intensity. The critical rainfall threshold for causing geological disasters deduced based on the rainfall intensity - precipitation duration has certain reference significance for the meteorological early warning of geological disasters in Beijing. The simulation of hydrological process elements such as regional runoff, slope runoff depth and soil moisture in Beijing based on the hydrological model also has good guiding significance for early warning.

从2018年7月16日北京暴雨过程雨情和地质灾害灾情出发,介绍了此次过程的地质灾害气象预警及检验;并基于北京区域地质灾害易发度信息,结合多源融合定量降水估测(QPE)驱动CREST水文模型模拟径流量与土壤湿度特征、过程雨强特征,分析了北京本次地质灾害气象成因。结果表明,北京北部和西部处于地质灾害中、高易发区,区(县)小时累计面雨量达到50 mm以上易发生灾害,降水持续24 h后是地质灾害的高发时段,灾害常发生于雨强较大峰值后的15 h内;基于雨强-降水持续时间推求的地质灾害致灾临界雨量阈值对北京地区地质灾害气象预警有一定的借鉴意义;基于水文模型的北京区域径流量、坡面径流深、土壤湿度等水文过程要素模拟对预警也有较好的指导意义。