Li et al. (2025) Integrating GNSS 3D deformation and GRACE/GRACE-FO gravity observations for terrestrial water storage changes and drought monitoring in Southwest China

Identification

• Journal: Journal of Hydrology
• Year: 2025
• Date: 2025-11-22
• Authors: Nengfang Chao, Shaofeng Bian
• DOI: 10.1016/j.jhydrol.2025.134654

Research Groups

• School of Electrical Engineering, Naval University of Engineering, Wuhan, China
• China Hubei Key Laboratory of Marine Geological Resources, College of Marine Science and Technology, China University of Geosciences, Wuhan, China
• Key Laboratory of Geological Exploration and Evaluation, China University of Geosciences (Wuhan), Wuhan, China

Short Summary

This study pioneers the integration of GNSS 3D deformation with GRACE/GRACE-FO observations using three fusion methods to derive daily and monthly terrestrial water storage (TWS) changes in Southwest China, significantly improving TWS accuracy and enabling detailed drought monitoring.

Objective

• To integrate Global Navigation Satellite System (GNSS) 3D deformation (horizontal and vertical) and Gravity Recovery and Climate Experiment (GRACE)/GRACE Follow-on (GRACE-FO) gravity observations to derive terrestrial water storage (TWS) changes and analyze the spatiotemporal characteristics of droughts in Southwest China.

Study Configuration

• Spatial Scale: Southwest China
• Temporal Scale: Daily and monthly terrestrial water storage changes; drought analysis for the second half of 2022–2023.

Methodology and Data

• Models used: Three different fusion methods (including virtual station method and priori information fusion method); Green’s function inversion with Slepian basis function used for comparison.
• Data sources: Global Navigation Satellite System (GNSS) 3D displacements, Gravity Recovery and Climate Experiment (GRACE) observations, GRACE Follow-on (GRACE-FO) observations.

Main Results

• Using only GNSS vertical displacement reduced the root mean square error (RMSE) of TWS changes by 28 % compared to the Slepian basis function with Green’s function inversion.
• Incorporating both horizontal and vertical GNSS displacements further improved the RMSE reduction to 43 %.
• Among the three fusion methods, the virtual station method performed best, significantly improving the spatial distribution of GNSS stations.
• The priori information fusion method was particularly advantageous for enabling daily TWS changes.
• The drought index derived from the daily fused TWS changes was below −1.3 during the second half of 2022–2023, indicating the most severe drought period in southwestern China.

Contributions

• First-time integration of horizontal and vertical (3D) GNSS displacements with GRACE/GRACE-FO observations to derive terrestrial water storage (TWS) changes.
• Development and evaluation of three distinct fusion methods for deriving daily and monthly TWS changes.
• Provides new data and technical support for monitoring TWS changes and drought conditions by integrating multi-source satellite observations, enhancing spatiotemporal resolution and accuracy.

Funding

• Not specified in the provided text.

Citation

@article{Li2025Integrating,
  author = {Li, Houpu and Chao, Nengfang and Bian, Shaofeng},
  title = {Integrating GNSS 3D deformation and GRACE/GRACE-FO gravity observations for terrestrial water storage changes and drought monitoring in Southwest China},
  journal = {Journal of Hydrology},
  year = {2025},
  doi = {10.1016/j.jhydrol.2025.134654},
  url = {https://doi.org/10.1016/j.jhydrol.2025.134654}
}