Xiong et al. (2026) SYSU TWSA v1.0: global high-resolution terrestrial water storage anomalies via satellite gravimetry

Identification

• Journal: Earth system science data
• Year: 2026
• Date: 2026-07-03
• Authors: Y. Xiong, Wei Feng, Jun Huang, Hongbing Bai, Guangyu Jian, Min Zhong
• DOI: 10.5194/essd-18-4537-2026

Research Groups

• School of Geospatial Engineering and Science, Sun Yat-Sen University, Zhuhai 519082, China
• Key Laboratory of Comprehensive Observation of Polar Environment (Sun Yat-Sen University), Ministry of Education, Zhuhai 519082, China

Short Summary

This study presents SYSU TWSA v1.0, a global high-resolution terrestrial water storage anomaly dataset derived from satellite gravimetry. The dataset is generated using a joint-inversion spatial downscaling framework that integrates large-scale constraints from GRACE/GFO and high-resolution spatial patterns from the WaterGAP Global Hydrological Model.

Objective

• To develop a high-resolution TWSA product to alleviate the scarcity of global high-resolution datasets.
• To better represent glacierized regions and large lakes in the dataset.

Study Configuration

• Spatial Scale: 0.5° grid resolution.
• Temporal Scale: Monthly data from April 2002 to December 2022.

Methodology and Data

• Models used: WaterGAP Global Hydrological Model (WGHM) and joint-inversion spatial downscaling framework.
• Data sources: GRACE/GFO Level 2 gravity field products, WGHM outputs, mountain glacier catalogue, hydrometeorological data from ERA5-Land, and in situ ground wells data.

Main Results

• The SYSU TWSA product shows good agreement with GRACE/GFO at the basin scale, with coefficients of determination (R2) exceeding 0.85 across basin-size classes.
• Consistency with terrestrial water fluxes derived from the basin water-balance equation improves substantially for small basins.
• Agreement with groundwater wells also improves, with correlations increasing at 67.7% of 28,248 wells.

Contributions

• The study provides a new high-resolution TWSA product that better represents glacierized regions and large lakes.
• The joint-inversion spatial downscaling framework used in this study is an innovative approach to improve the accuracy of downscaled products.

Funding

• This research was funded by the National Natural Science Foundation of China (Grant No. 41661144003) and the Guangdong Provincial Key Laboratory of Urbanization and Geo-simulation (Grant No. 2020GK1023).

Citation

@article{Xiong2026SYSU,
  author = {Xiong, Y. and Feng, Wei and Huang, Jun and Bai, Hongbing and Jian, Guangyu and Zhong, Min},
  title = {SYSU TWSA v1.0: global high-resolution terrestrial water storage anomalies via satellite gravimetry},
  journal = {Earth system science data},
  year = {2026},
  doi = {10.5194/essd-18-4537-2026},
  url = {https://doi.org/10.5194/essd-18-4537-2026}
}