Role of Terrestrial Evapotranspiration on the Occurrence of Flash Droughts in Northeast Asia

Flash Droughts (FDs), known for their rapid development and intensification, pose significant risks to ecosystems. To improve drought monitoring capabilities, a thorough examination of FD events and their characteristics is essential. In this context, we conducted an analysis of FD occurrences across Northeast Asia (NEA), utilizing data from the Global Land Data Assimilation System (GLDAS) from 2012 to 2022. FD events are identified using the stress-based Standardized Evaporative Stress Ratio (SESR) approach, followed by an assessment of their frequency and duration. To address the causes of FD events, they are further classified into three distinct types based on changes in Actual Evapotranspiration (AET) and Potential Evapotranspiration (PET). The results reveal that there are distinct spatial patterns in the occurrence of FD events, and it is possible to distinguish FDs under energy- and water-limited conditions using the ET-based classification. Further insights are expected to be revealed by an in-depth analysis on FD mechanisms including the impacts of climate change.