Understanding temperature-driven drought intensification in Northeast Asia through multiple drought indices

Study region Northeast Asia encompasses diverse hydroclimatic conditions across nine Köppen climate zones. Study focus This study investigates the spatiotemporal dynamics of drought intensification in Northeast Asia (NEA) using the Standardized Precipitation Index (SPI), the Standardized Precipitation-Evapotranspiration Index (SPEI), and the Evaporative Demand Drought Index (EDDI). We apply a multi-index framework with General Linear Modeling (GLM) to assess the effects of climatic variables on drought severity. Drought characteristics are assessed at 1-, 3-, 6-, and 12-month timescales using ERA5 reanalysis data from 1974 to 2023. New hydrological insights Trend analysis reveals a shift from seasonal droughts before 2004 to prolonged events. Northern China and Mongolia emerge as major long-term drought hotspots. SPEI and EDDI consistently display greater sensitivity to temperature-driven droughts than SPI. GLM analysis shows that minimum temperature has the strongest association with drought intensification (η²p = 0.046–0.105), followed by dewpoint temperature (η²p = 0.037–0.077). EDDI demonstrates the highest sensitivity in minimum temperature (η²p = 0.105), whereas SPI exhibits the weakest response (η²p = 0.046). Rising temperature and solar radiation intensify droughts, while higher dewpoint temperature reduces severity. These findings indicate that drought intensification in NEA is primarily associated with interacting temperature and energy-related processes rather than precipitation alone. This multi-index, climate-stratified approach provides a mechanistic understanding of water–energy interactions driving drought variability, supporting monitoring and adaptive water management under climate change.