Nguyen et al. (2026) Dynamics of model-based groundwater-land surface response times as a dryland flash drought diagnostic

Identification

• Journal: Communications Earth & Environment
• Year: 2026
• Date: 2026-07-06
• Authors: Hoang Hai Nguyen, Di Long, S.-Y. Simon Wang, Jin‐Ho Yoon, Yulong Zhong, Hyunglok Kim
• DOI: 10.1038/s43247-026-03783-7

Research Groups

• Department of Environment and Energy Engineering, Gwangju Institute of Science and Technology (GIST)
• Department of Hydraulic Engineering, State Key Laboratory of Hydroscience and Engineering, Tsinghua University
• Department of Agronomy, Kasetsart University
• School of Geography and Information Engineering, China University of Geosciences (Wuhan)

Short Summary

This study examines the dynamics of model-based groundwater-land surface response times as a dryland flash drought diagnostic. The results show that background atmospheric aridity generally controls the relationship between modeled Topt and flash droughts, while seasonal variability is largely governed by terrestrial wetness conditions.

Objective

• Investigate the global relationships between modeled groundwater response time (Topt) and flash droughts using a dynamic exponential filter model.
• Analyze the collocation of long Topt-flash drought occurrence frequency across climate regions.
• Discuss the role of major land-atmosphere interactions in controlling groundwater-flash drought relationship.

Study Configuration

• Spatial Scale: Global scale, with focus on dryland regions.
• Temporal Scale: Long-term (2004-2023) datasets from a satellite data-assimilated land surface model.

Methodology and Data

• Models used: Dynamic exponential filter model to characterize the variation of groundwater response time based on its derived Topt parameter dynamics.
• Data sources: Satellite-based terrestrial water storage data assimilation into a physically-based land surface model, with datasets from multiple hydroclimatic variables.

Main Results

• The collocation hotspots of long Topt and frequent flash droughts are concentrated in drylands (arid, semi-arid, and dry sub-humid) regions.
• Seasonal bidirectional sensitivities between Topt and flash drought characteristics show that the timings of flash drought events exert a control opposite to their intensities.
• The combined evapotranspiration-runoff deficit, especially the dominance of evapotranspiration, accelerates subsurface moisture depletion that triggers flash drought onset.

Contributions

• This study highlights the potential use of groundwater response time (Topt) as a promising model-based diagnostic indicator of spatiotemporal flash drought dynamics.
• The findings underscore the importance of considering both atmospheric and terrestrial factors in understanding flash drought propagation.

Funding

• This research was supported by the National Research Foundation of Korea (NRF) under grant number NRF-2020R1A2C3009753.

Citation

@article{Nguyen2026Dynamics,
  author = {Nguyen, Hoang Hai and Long, Di and Wang, S.-Y. Simon and Yoon, Jin‐Ho and Zhong, Yulong and Kim, Hyunglok},
  title = {Dynamics of model-based groundwater-land surface response times as a dryland flash drought diagnostic},
  journal = {Communications Earth & Environment},
  year = {2026},
  doi = {10.1038/s43247-026-03783-7},
  url = {https://doi.org/10.1038/s43247-026-03783-7}
}