Bridging Terrestrial Water Storage Anomaly During GRACE/GRACE-FO Gap Using SSA Method: A Case Study in China

Area of Science:

• Earth Science
• Hydrology
• Geophysics

Background:

• The gap between GRACE and GRACE-FO missions poses challenges for studying terrestrial water storage anomalies (TWSA).
• Accurate TWSA data is crucial for understanding hydrological changes and water resource management.

Purpose of the Study:

• To propose and evaluate Singular Spectrum Analysis (SSA) for predicting TWSA to bridge the GRACE-GRACE-FO data gap.
• To compare the accuracy of SSA predictions with traditional methods like ARMA.

Main Methods:

• Applied SSA to GRACE RL06 data from January 2003 to August 2016 across six regions in China.
• Compared SSA prediction accuracy (R, NSE, RMSE) with ARMA models.
• Verified SSA predictions using Mascon RL06, GLDAS, and GRACE-FO data.

Main Results:

• GRACE-derived TWSA showed high consistency with Mascon data, particularly Mascon RL06.
• SSA significantly improved prediction accuracy (higher R, NSE; lower RMSE) compared to ARMA.
• SSA predictions for 2016-2019 aligned well with GLDAS and GRACE-FO data.

Conclusions:

• SSA is a reliable method for predicting TWSA and bridging the GRACE-GRACE-FO data gap.
• The study provides a valuable reference for hydrological research and water resource management.
• SSA demonstrates superior performance in capturing periodic and trending characteristics of TWSA.