Tripathy et al. (2025) Spatiotemporal dynamics of surface and rootzone soil moisture droughts

Identification

• Journal: Journal of Hydrology
• Year: 2025
• Date: 2025-10-24
• Authors: Kumar Puran Tripathy, Ashok K. Mishra
• DOI: 10.1016/j.jhydrol.2025.134455

Research Groups

Zachry Department of Civil and Environmental Engineering, Texas A&M University, College Station, TX, USA

Short Summary

This study employed a Complex Network framework and event synchronization to analyze summer surface and root-zone soil moisture droughts across the contiguous United States, identifying the Ohio River Valley as a central drought hub and revealing a west-to-east propagation pattern with stronger spatial coherence in root-zone soil moisture.

Objective

• To analyze summer surface soil moisture (SSM) and root-zone soil moisture (RZSM) droughts across the contiguous United States (CONUS) using a Complex Network (CN) based framework.
• To identify the timing, sequence, co-occurrence, and directional propagation of soil moisture drought events across regions.

Study Configuration

• Spatial Scale: Contiguous United States (CONUS)
• Temporal Scale: Seasonal (summer)

Methodology and Data

• Models used: Complex Network (CN) based framework, Event synchronization, Undirected and directed networks, Community detection, Inter-Community Synchronization Strength (ICSS) metric.
• Data sources: Not explicitly mentioned in the provided text.

Main Results

• The Midwest, particularly the Ohio River Valley, was identified as a central hub for soil moisture drought, exhibiting high values of degree and eigenvector centrality.
• In the RZSM networks, elevated betweenness centrality in the central CONUS highlighted regions acting as bridges for transmitting subsurface dryness.
• Directional analysis revealed a west-to-east propagation pattern, with eastern Nebraska and northern Missouri identified as key source regions, while the Ohio River Valley consistently functioned as a sink.
• Community detection identified ten distinct communities in the SSM network and six larger, more spatially coherent communities in the RZSM network, based on similar soil moisture drought dynamics.
• The Inter-Community Synchronization Strength (ICSS) metric was higher for RZSM (0.32) than for SSM (0.145), indicating stronger spatial coherence and inter-regional connectivity in deeper soil layers.

Contributions

• Offers new insights into the spatiotemporal dynamics of soil moisture droughts by applying a novel network-based approach.
• Identifies key regional hubs, sources, and sinks for surface and root-zone soil moisture droughts across the CONUS.
• Quantifies the degree of drought synchronization and inter-regional connectivity, highlighting differences between surface and root-zone soil moisture.

Funding

Not explicitly mentioned in the provided text.

Citation

@article{Tripathy2025Spatiotemporal,
  author = {Tripathy, Kumar Puran and Mishra, Ashok K.},
  title = {Spatiotemporal dynamics of surface and rootzone soil moisture droughts},
  journal = {Journal of Hydrology},
  year = {2025},
  doi = {10.1016/j.jhydrol.2025.134455},
  url = {https://doi.org/10.1016/j.jhydrol.2025.134455}
}

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