Spatiotemporally Contiguous Extreme Drought and Wetness Events in China and their Impacts on Vegetation

Global warming has intensified the frequency and intensity of precipitation anomalies, resulting in extreme drought and wetness that severely affect ecosystems and society. While most existing studies often examine spatial or temporal aspects separately, few have treated these extremes as spatiotemporally contiguous events. Here, we analyze the distinct characteristics of spatiotemporally contiguous extreme drought and wetness events across China during 2001-2024, employing a three-dimensional perspective. The results show that since the 21st century, both extreme drought and wetness events have increased in duration. However, the spatial extent and intensity of drought events have decreased, whereas those of wetness events have expanded significantly. During the growing season, drought events tend to suppress vegetation growth in arid regions yet promote it in humid areas, whereas wetness events exhibit an opposite pattern. Moreover, drought events have detrimental impacts on forests, croplands, and grasslands, while wetness events benefit croplands and grasslands but continue to adversely impact forests. Our findings emphasize the necessity of studying extreme events from a three-dimensional spatiotemporal perspective.