三岔河上游一次暴雨洪水过程分析

Analysis of a rainstorm flood process in the upper reaches of Sancha River

本文利用流域自建雨量站与气象局国家站、区域站雨量资料,结合平寨水库坝上水位、流量数据,分析了2020年7月7日至7月9日三岔河上游洪水过程的雨情、水情特点,以及气象成因,研究结果表明:本次降雨过程持续时间长、范围广、强度大,降雨形成径流时间短,入库流量陡升陡降,并呈现双峰型分布,本次洪水过程主要由上游流域地表径流产生,高空槽、低空低涡切变线与地面辐合的配合,以及副高外围云系带来充沛的水汽条件、低层系统移动缓慢在流域内维持时间较长是形成本次暴雨洪水过程的重要原因。

Based on the data of Self-built precipitation station,National Meteorology precipitation station and Regional Meteorology precipitation station,Combine data of water level and rate of flow in Pingzhai Reservoir,Analysis the characteristics of rain condition,water regimen and meteorological causes of the flood in the upper reaches of Sancha River from July 7 to July 9,2020.The results show that the rainfall process lasts for a long time,has a wide range and high intensity.The runoff time caused by rainfall is short,and the inflow discharge rises and falls sharply,and presents a bimodal distribution.The flood process is mainly generated by the surface runoff of the upstream basin.The main reasons for this rainstorm and flood process are the coordination of the high-altitude trough,low-altitude vortex shear line and ground convergence,the abundant water vapor condition brought by periphery of Subtropical high,the slow movement of the lower layer system in the basin area and lasts for a long time.