Spatial and temporal distribution characteristics of rainfall in Daqing River Basin in the Haihe "23·7" basin-wide extreme flood

The Haihe River Basin experienced catastrophic flood, known as the "23·7" flood, due to the very heavy rainfall caused by Typhoon Doksuri. The rainfall in Daqing River Basin is the highest. Based on the hourly rainfall data of stations in Daqing River Basin, the temporal and spatial distribution characteristics of rainfall are analyzed by Kriging interpolation method. The results show that most of the rain occurred in 48 h，there are 3~4 peaks in the catchment rainfall. The ratio of maximum rainfall to total rainfall of 1 h, 6 h, 24 h and 48 h is 7%, 23%, 59% and 92%. The heavy rainfall( rainfall per hour equal or greater than 20 mm) in the basin lasts for a long time, which ranged from 59 to 74 h. The Manshuihe Station had the longest duration of heavy rainfall, accounting for 20% of the total rainfall duration. The rainstorm center is not fixed, the rainstorm center at 15:00 and 17:00 on July 30 was located in the southwest of the basin, the rest of the rainstorm center was basically located in the north and east of the basin, and the rainstorm center at 24: 00 on July 31 was located in the southwest of the basin. The rainfall is unevenly distributed in the basin, The spatial distribution of 1 h, 6 h and 24 h maximum rainfall is basically the same. The high value area is located in the eastern part of the northern basin, the low value area is located in the southern basin, and the high value area of the 72 h maximum rainfall is distributed in the central part of the basin.