Spatiotemporal Characteristics and Drivers of and Vegetation Responses to Flash Droughts over the Mongolian Plateau

Abstract

In this study, based on daily soil moisture, air temperature, and radiation data from the ERA5-Land reanalysis dataset spanning 1980–2021, flash-drought events on the Mongolian Plateau were identified. This research reveals the spatiotemporal characteristics and driving factors of flash droughts and hot flash droughts over the last 42 years on the Mongolian Plateau. The main results are as follows: (1) Spatially, flash droughts are concentrated in the southeastern and northern regions, with fewer occurrences in the west, and the intensity increases from southwest to northeast. Temporally, flash-drought events primarily occur in the summer. (2) An exploration of the meteorological driving mechanisms of flash droughts reveals that the occurrence rate of Standardized Precipitation Index (SPI) anomalies is higher than that of Potential Evapotranspiration (PET) anomalies during flash-drought periods. (3) GPP (Gross Primary Productivity) is most sensitive to flash droughts in spring and autumn, with the highest response rates in the southeast and northwest during autumn. The response rate is lower in summer and more evenly distributed. (4) Among vegetation types, croplands exhibited the highest GPP response rate, followed by grasslands, shrublands, broadleaf forests, and coniferous forests, although these differences may partly reflect contrasting climatic, topographic, and management settings. The findings of this study provide important scientific evidence and practical references for drought monitoring, adaptive management, and integrated ecosystem management on the Mongolian Plateau.