2026-10-07, 16:15–16:30 (Europe/Amsterdam), Room 18
Abstract
Flash droughts are increasingly recognized as a distinct class of hydroclimatic extremes marked by rapid soil-moisture depletion over only a few weeks. Because of their abrupt onset, these events can severely affect agricultural production, terrestrial ecosystems, and regional water resources before conventional drought indicators fully capture their development. Recent drought episodes across Europe have reinforced the need to better understand how flash drought behaviour may evolve under continued climate warming. Yet substantial uncertainty remains, partly because many previous assessments rely on meteorological indicators or single datasets that do not adequately represent the subsurface soil-moisture processes governing rapid drought emergence.
This study proposes to investigate the future evolution of flash drought characteristics across Europe using root-zone soil moisture simulations from a multi-model ensemble of global hydrological models, including WaterGAP, H08, and CWatM, forced by bias-adjusted CMIP6 climate projections. Daily soil-moisture outputs will be aggregated to pentad scale (5-day averages) to reduce high-volatility while preserving the rapid depletion signals associated with flash drought onset. Root-zone soil moisture will then be transformed into grid-specific climatological percentiles, enabling a temporally and spatially consistent identification of flash drought events across models and time periods. A key methodological contribution of this study is the integration of pentad-scale root-zone soil moisture percentiles with a multi-model hydrological ensemble, enabling a consistent and process-relevant assessment of future flash drought dynamics across Europe.
Using this framework, the study will assess potential changes in flash drought frequency, duration, severity, and onset speed under historical conditions and future projections for SSP1-2.6, SSP2-4.5, and SSP5-8.5. The analysis is intended to advance understanding of future rapid drought development and to support drought risk assessment, climate adaptation planning, and early-warning strategies across Europe.
Keywords: Flash drought; Root-zone soil moisture; Global hydrological models; CMIP6; Europe.
This study examines how flash drought characteristics may change across Europe under future climate scenarios using multi-model root-zone soil moisture simulations from global hydrological models forced by CMIP6 projections. The framework combines pentad-scale percentile diagnostics with ensemble-based analysis to provide physically grounded insights for drought risk assessment and early-warning planning.
Dr. Vaibhav Kumar is a Postdoctoral Research Fellow at CNR-IRPI, Italy, working under the supervision of Dr. Luca Brocca. His research focuses on the integration of satellite observations, reanalysis, and hydrological model data for environmental monitoring, with particular emphasis on flash drought detection, soil moisture dynamics, and hydroclimatic extremes. He received his Ph.D. in Geomatics engineering from National Cheng Kung University, Taiwan. His expertise includes multi-sensor Earth observation, geospatial data harmonization, uncertainty analysis, and machine learning for large-scale environmental applications. His work supports engineering-oriented monitoring frameworks for hazard assessment, early warning, and climate resilience.