Spatial and temporal variation characteristics of extreme hydrometeorological events in the Yellow River Basin and their effects on vegetation

摘要

Abstract Extreme hydrometeorological events have an effect on the growth of vegetation worldwide. Here, we used China's Yellow River Basin to deeply explore the temporal and spatial trends of extreme hydrometeorological events and their impacts on vegetation. We identified extreme drought (Dry-PRE, Dry-VPD) and extreme wet (Wet-PRE, Wet-VPD) events based on precipitation and vapor pressure deficit (VPD). In this paper, the interannual variation of extreme hydrometeorological events in the Yellow River Basin, their temporal and spatial distribution patterns and their impacts on vegetation were analyzed by combining with normalized difference vegetation index and precipitation. The results indicated that Dry-VPD, Dry-PRE and Wet-PRE events showed an upward trend year by year, Wet-VPD events showed a downward trend year by year, and Dry-VPD and Dry-PRE events increased significantly. Overall, the environment of the Yellow River Basin continued to dry out. The sensitivity of vegetation in the Yellow River Basin to extreme drought events was higher compared with that to extreme wet events. Extreme drought events based on VPD might affect vegetation growth in the upstream western region and the downstream region of the Yellow River Basin, while extreme drought events based on PRE might affect vegetation growth in the central region of the Basin. This paper showed that, in addition to the impact of precipitation on vegetation, drought caused by VPD also had a significant impact on vegetation. Furthermore, we suggested strengthening the protection of vegetation where the trend was significant.