Long et al. (2025) Assessing the Consistency Among Three Mascon Solutions and COST-G-Based Grid Products for Characterizing Antarctic Ice Sheet Mass Change

Identification

• Journal: Remote Sensing
• Year: 2025
• Date: 2025-11-12
• Authors: Qing Long, Xiaoli Su
• DOI: 10.3390/rs17223699

Research Groups

• National Gravitation Laboratory, Institute of Geophysics, MOE Key Laboratory of Fundamental Physical Quantities Measurement, and School of Physics, Huazhong University of Science and Technology, Wuhan 430074, China

Short Summary

This study comprehensively assesses the consistency of three GRACE/GRACE-FO mascon solutions (CSR, JPL, GSFC) and COST-G-based grid products for characterizing Antarctic Ice Sheet (AIS) mass change from 2003 to 2023, revealing overall good agreement but significant discrepancies in specific regions like the Antarctic Peninsula and during the late GRACE mission period.

Objective

• To systematically evaluate the consistency among three major mascon solutions (CSR, JPL, GSFC) and COST-G-based gridded products in characterizing Antarctic Ice Sheet (AIS) mass changes across multiple temporal scales (monthly, seasonal, annual, interannual, and long-term trends) and spatial scales (entire AIS and its subregions).

Study Configuration

• Spatial Scale: Antarctic Ice Sheet (AIS), including the Antarctic Peninsula Ice Sheet (APIS), West Antarctic Ice Sheet (WAIS), and East Antarctic Ice Sheet (EAIS). Grid resolutions vary: CSR (0.25° × 0.25°), JPL (0.5° × 0.5° with 3° × 3° effective resolution), GSFC (0.5° × 0.5° equal angle), and COST-G (gridded products).
• Temporal Scale: January 2003 to December 2023 (21 years), covering the GRACE and GRACE Follow-On (GRACE-FO) missions.

Methodology and Data

• Models used:
  • Glacial Isostatic Adjustment (GIA) correction: ICE6G-D model (for CSR, JPL, GSFC) and ICE-6G_D (VM5a) model (for COST-G).
  • Tidal model: GOT 4.7 (for GSFC).
  • Regularization: Tikhonov regularization with L-ribbon approach (for CSR).
  • Filtering/Smoothing: Anisotropic filter (VDK filter) for COST-G.
  • Gap-filling: Linear interpolation for 1-2 month gaps, Singular Spectrum Analysis (SSA) for the 11-month inter-mission gap.
  • Trend and seasonal signal extraction: Least squares fitting of a mathematical model including linear and seasonal (1-year and half-year periodicity) components. Interannual variations derived by removing these components and applying a one-year moving average.
  • Consistency quantification: Intraclass Correlation Coefficient (ICC) using a bidirectional random-effects model with absolute agreement.
• Data sources:
  • GRACE/GRACE-FO satellite observations.
  • Three mascon products: Center for Space Research (CSR) RL06.3, Jet Propulsion Laboratory (JPL) RL06.3Mv04, and Goddard Space Flight Center (GSFC) RL06v2.0.
  • Combination Service for Time-variable Gravity fields (COST-G) Level-3 ice mass change products from the Gravity Information Service (GravIS).
  • Degree 1 coefficients (geocenter corrections) from Technical Note 13 (TN-13a).
  • Degree 2 order 0 (C20) and Degree 3 order 0 (C30) coefficients from Satellite Laser Ranging (SLR).
  • Atmosphere and Ocean De-aliasing Level-1B (AOD1B) 'Grid Azimuth Determination (GAD)' fields (for CSR, GSFC).

Main Results

• High consistency (ICC values > 0.94) was observed among the four datasets for the entire AIS and its subregions' mass change time series from 2003 to 2023.
• The largest differences in mass change time series occurred in the Antarctic Peninsula Ice Sheet (APIS).
• Mass trend estimates showed better agreement over longer periods and larger regions, but differences of 20–40% were found during the late stage of GRACE and the entire GRACE-FO timespan.
• Similar spatial patterns for mass accelerations were identified: approximately 3 Gt/yr² positive acceleration in APIS and George V Land, and approximately -4 Gt/yr² negative acceleration in Amundsen Sea Embayment (ASE) and Wilkes Land.
• Notable discrepancies in annual mass change statistics for the Eastern AIS (EAIS) in 2016 led to inconsistent signs of annual AIS mass change between CSR and JPL/GSFC.
• Interannual mass variations generally agreed well (ICC values > 0.87) across the AIS and its subregions, with the exception of the period from mid-2016 to mid-2018.
• Excluding annual mass variations from 2016 and 2017 significantly increased ICC values for the AIS, WAIS, and EAIS, but slightly decreased for the APIS.
• Excluding the GRACE/GRACE-FO data gap period (July 2017 to May 2018) had minimal impact on the ICC values for monthly and interannual mass variations.

Contributions

• Provides the first comprehensive evaluation of consistency among three mainstream mascon products (CSR, JPL, GSFC) and COST-G-based gridded products for characterizing Antarctic Ice Sheet mass change.
• Identifies specific regions (e.g., APIS) and time periods (e.g., late GRACE mission, 2016-2018) where significant discrepancies exist, guiding future applications and uncertainty assessments.
• Offers key insights for improving algorithms for mascon solutions and grid products, particularly for regions with complex topography and during periods of degraded satellite data quality.
• Serves as a valuable reference for the geoscientific community in selecting appropriate GRACE/GRACE-FO grid datasets for multidisciplinary applications, including ice mass balance studies, sea-level rise projections, and climate forcing response analyses.

Funding

• National Natural Science Foundation of China (No. 42474119)

Citation

@article{Long2025Assessing,
  author = {Long, Qing and Su, Xiaoli},
  title = {Assessing the Consistency Among Three Mascon Solutions and COST-G-Based Grid Products for Characterizing Antarctic Ice Sheet Mass Change},
  journal = {Remote Sensing},
  year = {2025},
  doi = {10.3390/rs17223699},
  url = {https://doi.org/10.3390/rs17223699}
}