Zhang et al. (2026) A spatiotemporal reconstruction framework for GRACE/GRACE-FO-derived groundwater storage anomalies based on historical phase-constrained gap filling and physics-guided global–local downscaling

Identification

• Journal: International Journal of Applied Earth Observation and Geoinformation
• Year: 2026
• Date: 2026-09-19
• Authors: Leyi Zhang, Guozhuang Zhang, Hongjie He, Yijian Zeng, Xizhi LYU, Zuyu Liu, Xiuhua Liu, Peizhe Li, Bing Bai, Xia Li
• DOI: 10.1016/j.jag.2026.105603

Research Groups

• School of Water and Environment, Key Laboratory of Subsurface Hydrology and Ecological Effect in Arid Region of Ministry of Education, Key Laboratory of Ecohydrology and Water-Security in Arid and Semi-arid Regions of Ministry of Water Resources, Chang’an University, Xi’an 710054, China
• School of Land Engineering, Chang’an University, Xi’an 710054, China
• Hinton STAI Institute and School of GeoAI, East China Normal University, Minhang, Shanghai 200241, China
• Faculty of Geo-Information Science and Earth Observation, University of Twente, Hengelosestraat 99, Enschede 7514 AE, the Netherlands
• Yellow River Institute of Hydraulic Research, Zhengzhou 450003, China

Short Summary

This study developed an integrated spatiotemporal reconstruction framework for GRACE/GRACE-FO-derived groundwater storage anomalies (GWSA) by combining historical phase-constrained gap filling with physics-guided global–local downscaling. The framework was applied to the Three-North Region of China and showed improved performance in preserving regional-scale consistency, internal validation, and local spatial detail.

Objective

• Reconstruct a continuous GRACE/GRACE-FO-derived GWSA series by bridging the 11-month mission gap without external forcing data.
• Generate a 1 km downscaled GWSA product for the Three-North Region of China using a physics-guided global–local downscaling framework with residual compensation and coarse-scale consistency correction.

Study Configuration

• Spatial Scale: The study area is the Three-North Region of China, which spans northeastern, northern, and northwestern China.
• Temporal Scale: The temporal coverage is from April 2002 to December 2022.

Methodology and Data

• Models used: KGC-SSA (Kling-Gupta Efficiency-based singular spectrum analysis method) for gap filling and GLR-GWXGB (Global-Local-Residual Geographically Weighted Extreme Gradient Boosting) framework for downscaling.
• Data sources: GRACE/GRACE-FO data, GLDAS (Global Land Data Assimilation System), MOD13A3 product, PML-V2 dataset, ERA5-Land reanalysis, and others.

Main Results

• The KGC-SSA method reconstructed the 11-month mission gap with a mean ensemble reconstruction spread of 0.06 cm.
• The GLR-GWXGB framework improved internal validation performance, preserved regional-scale consistency with the original GRACE-derived GWSA, and enhanced local spatial detail.

Contributions

• This study provides a robust approach for generating temporally continuous and spatially refined groundwater-storage information from GRACE/GRACE-FO observations.
• The proposed framework addresses the challenges of temporal discontinuity and coarse spatial resolution in GRACE/GRACE-FO-derived GWSA.

Funding

• Not specified.

Citation

@article{Zhang2026spatiotemporal,
  author = {Zhang, Leyi and Zhang, Guozhuang and He, Hongjie and Zeng, Yijian and LYU, Xizhi and Liu, Zuyu and Liu, Xiuhua and Li, Peizhe and Bai, Bing and Li, Xia},
  title = {A spatiotemporal reconstruction framework for GRACE/GRACE-FO-derived groundwater storage anomalies based on historical phase-constrained gap filling and physics-guided global–local downscaling},
  journal = {International Journal of Applied Earth Observation and Geoinformation},
  year = {2026},
  doi = {10.1016/j.jag.2026.105603},
  url = {https://doi.org/10.1016/j.jag.2026.105603}
}