Abstract:Studying the drought condition in the water source area and receiving area of the Middle Route Project of South-to-North Water Diversion Project is of great significance for the water resource scheduling and operation management of the project. Based on the NCEP-NCAR reanalysis data and the daily average temperature, precipitation, and meteorological drought composite index of all meteorological stations in the water source area and receiving area of Middle Route Project of South-to-North Water Diversion Project from 1961 to 2023, this article conducts identification and assessment of regional drought processes in water source area and receiving area. The results show that the annual values of drought days in the water source area and receiving area are 101 d and 114 d, respectively, presenting an overall spatial distribution feature of “more in the middle and less at both ends”. The northern part of Henan and the southern part of Hebei in the water receiving area are high-value areas of drought days. The number of drought days in most of the water source areas, most of the water receiving areas in Henan and eastern Hebei is increasing, while the number of drought days in most of the water receiving areas in the northern, western and southern parts of Hebei, Beijing and Tianjin is decreasing. Using the dynamic regional drought process identification method, a total of 97 regional drought processes have been identified in the study area since 1961. Using the percentile method to divide the intensity index of regional drought processes, we obtain the threshold values corresponding to different intensity levels, and a total of 4 “extremely heavy”, 15 “heavy”, 30 “relatively heavy”, and 48 “moderate” regional drought processes in the study area. The heaviest 3 regional drought processes occurred in 1968, 2001 and 1997, and the differences in circulation characteristics led to significant differences in the spatial and temporal distribution of drought days and the proportion of drought stations at different levels among the three processes. Among the 97 regional drought processes in the study area, 54.6% were droughts in the water source area but not in the water receiving area, which is beneficial for engineering water diversion. At the same time, in some years, the entire region is uniformly dry or the water source area is dry while the water receiving area is not dry. This is not conducive to engineering water diversion. Therefore, for the water resource scheduling of the Middle Route Project of South-to-North Water Diversion Project, the targeted water diversion work needs to be carried out based on the actual situation.