Intercomparison of Spherical Harmonics and Mascons for GRACE-based Mass Change Estimates

Abstract This study evaluates two common methods for estimating mass changes from GRACE inter-satellite observations: spherical harmonics (SH) and mass concentration (mascon) solutions. Using a numerical simulation framework, we compare their performance for single-pair GRACE-like and double-pair Bender-type missions based on global RMS of residuals and degree-dependent spectral power. The analysis focuses on gravity field recovery using global 3° equal-area mascons and SH coefficients up to degree and order (d/o) 60. Mascon parameters are converted into equivalent SH coefficients for consistent spatial and spectral comparison. Results show that mascon solutions achieve lower global RMS residuals due to spatial averaging and geophysical-based regularization, whereas SH solutions preserve high-degree spectral power but are more affected by aliasing. These findings highlight the complementary strengths of the two parameterizations in gravity field recovery.