Author(s): Chuchu Zhang; Yuyan Zhou; Fan Lu; Jin Sun; Yingying Hu; Jianwei Liu; Jiayue Zhang; Zeying Yin; Mengyi Ji
Linked Author(s): Jianwei Liu
Keywords: Extreme hydrological processes; Multi-source remote data; Indicators of Hydrologic Alteration; River source regions; Qinghai-Tibet Plateau
Abstract: The Qinghai-Tibet Plateau has undergone significant climatic change, leading to an increasing likelihood of extreme hydrological events, e. g. rainstorms and floods, seasonal water scarcity, the shrinkage or even disappearance of lakes. In this study, the historical evolution characteristics and risks analysis of extreme hydrological events in the river source region were conducted. The variation patterns of precipitation extreme values were analyzed using multi-source remote sensing precipitation data including IMERG and ERA5-land. The Indicators of Hydrologic Alteration method was used to analyze the variations of discharge extreme value in typical watersheds. Using the data of lake level and area, the characteristics of lake change were analyzed. A comprehensive drought index considering snowmelt was constructed to study the evolution characteristics of drought. The results showed that the precipitation index Rx3day increased and CDD decreased in the source regions of Yangtze River and Yellow River. The frequency of runoff maxima increased in the Yangtze River Source Region, and the frequency increased most in banma of Dadu River basin. The frequency of runoff minima decreased in the Yellow River Source Region, but the time of runoff minima increased. Lakes in the northeastern part of the Qinghai-Tibet Plateau showed an expanding trend, and the average rising rate of lake water level in Selin Co was 0.56 m/a. The southern lakes showed a shrinking trend. Duoqing Co has been reduced by one third. Although the Yellow River Source Region shows a trend of wetting on different time scales, the frequency of short-term drought is high.
Year: 2024