Dynamics of groundwater drought in the Yellow River source area and its surface influences

Yellow River source area in China. The primary objective of this study is to investigate the dynamic evolution of groundwater drought events in the source area of the Yellow River over the past two decades. By adopting a three-dimensional perspective, the study aims to characterize and quantify the severity of droughts and analyze their spatiotemporal characteristics. In addition, it explores the seasonal relationships between groundwater drought and key surface factors—elevation, slope, and land use. This study systematically identifies persistent groundwater drought events and their consistent spatial centers, setting it apart from previous research that primarily focused on single indices or short-term trends. The most severe drought event occurred between 2017 and 2018. By incorporating surface factors such as elevation, slope, and land use, and examining their seasonal interactions with drought patterns, the study reveals that high-elevation, steep-slope areas, as well as regions dominated by bare land or grassland, are more vulnerable to groundwater drought, particularly during winter. In contrast, wetlands and water bodies exhibit low and stable drought risk. Unlike prior studies that mainly emphasized macro-level drivers, this research places greater focus on surface conditions influencing groundwater drought. These findings enhance understanding of hydrological mechanisms in fragile plateau regions and help identify high drought-risk areas for targeted management. • Identifies persistent groundwater drought events and their stable spatial centers. • Constructs a 3D framework to quantify drought severity and spatiotemporal evolution. • Explores seasonal relationships between drought and elevation, slope, land use types. • Reveals high drought risk in high-altitude, steep-slope, and grassland or bare areas.