Three-Dimensional Identification and Characterization of Drought Events in the Loess Plateau

Understanding the propagation of drought from meteorological anomalies to vegetation stress is critical for risk assessment, yet traditional methods often fail to capture the complete spatiotemporal evolution of drought events. This study identified meteorological and vegetation drought events across three dimensions (two-dimensional space and one-dimensional time) in the Loess Plateau of China from 2001 to 2022. As a result, the area, duration, severity, and migration of each event were characterized to reveal their spatiotemporal patterns. We identified 39 meteorological and 63 vegetation events, which show strong concordance with historical records. Results show that while meteorological droughts exhibited cyclical patterns, vegetation droughts showed a significant mitigating trend post-2010. The central Loess Plateau consistently emerged as the primary hotspot for drought frequency and severity, with events concentrated in spring and summer. Analysis of 20 matched meteorological-vegetation event pairs indicates that post-2010, the response of vegetation to meteorological drought was delayed, suggesting enhanced drought resistance of the vegetation following ecological restoration. These findings provide a scientific basis for regional drought risk assessment and offer quantitative evidence of the effectiveness of ecological restoration.