A global model-based analysis for 2004–2023 found longer groundwater response time (Topt) where flash droughts are frequent in drylands, while seasonal sensitivity depends strongly on background terrestrial wetness. Topt may be a useful diagnostic for forecasting, but it remains a model-derived indicator rather than a globally field-validated warning system.
Key findings
- Background atmospheric aridity structured the spatial relationship: dryland flash-drought hotspots had longer Topt. Seasonal variability was governed by terrestrial wetness, with stronger bidirectional sensitivity in wetter seasons. Under dry conditions, combined evapotranspiration–runoff deficits, especially evapotranspiration dominance, prolonged Topt and reduced sensitivity.
Why this matters globally
If validated against monitoring wells, Topt could help prioritise risk, manage groundwater and complement surface indicators in early-warning systems, especially where dryland impacts develop rapidly.
Thai researcher contribution
S.-Y. Simon Wang of Kasetsart University's Department of Agronomy contributed expertise on land–atmosphere interaction and drought. The evidence is global and model-based, not a Thailand-specific assessment.
Limitations to consider
Groundwater is model-derived and lacks homogeneous global well validation. Resolution may miss aquifer geology, pumping, irrigation and local hydrogeology, while statistical association does not by itself establish operational forecast skill.