COM-TG: A combined mascon product from multiple analyses of GRACE and GRACE Follow-On space gravity data

Abstract

Currently available GRACE and GRACE Follow-On (GRACE(-FO)) mascon solutions differ due to variations in parameterization, regularization and land-ocean classification, leading to inconsistencies in regional mass change estimates. To reduce dependence on any single processing strategy, we present the first fused mascon solution, COM-TG, derived from four independent GRACE(-FO) products generated by separate analysis centers and combined within a consistent inversion framework. Prior to fusion, inconsistencies in land-ocean signal attribution were addressed using a coastline resolution improvement (CRI) approach. The fused solution is solved on $\sim$100~km mascons delimited by coastlines and grounding lines, and is shown to be relatively insensitive to the choice of observation weighting used. It mitigates center-specific regularization assumptions, suppresses noise relative to individual input products and preserves meaningful spatial variability. The resulting product provides a unified representation of GRACE(-FO) mass changes for hydrological, oceanographic and cryospheric applications.