Simulated gravity field data

The SING database provides simulated gravity field data products derived from a dedicated end-to-end simulation framework. These simulations are performed for three mission scenarios — GRACE-C-like, NGGM, and MAGIC — and across four simulation types: high-frequency, monthly, trend-only, and trend-and-annual. The data are structured in four levels, each representing a different stage of processing:

Level 2a: Raw spherical harmonic coefficients of the Earth's gravity field in ICGEM format.
Level 2b: Filtered spherical harmonic coefficients using the VADER anisotropic filtering approach, also in ICGEM format.
Level 2P: Surface mass anomaly grids (in equivalent water height, EWH) computed from Level 2a and 2b, provided in NetCDF format at 1° × 1° spatial resolution.
Level 3: Final surface mass anomaly grids with Glacial Isostatic Adjustment (GIA) corrections applied, also in NetCDF format.

These data products are based on simulated observations processed by the Reduced Scale Simulator (RSS), a closed-loop numerical simulator designed to model the key elements of gravity missions. It integrates instrument noise, background model errors, and realistic satellite orbits. The simulations utilize target Earth signals from the ESA Earth System Model ESM 2.0, particularly the Hydrology, Ice, and Solid Earth (HIS) components.

Key processing steps include:

Simulation of inter-satellite observations based on synthetic Earth gravity signals.
Estimation of Stokes coefficients via least squares adjustment.
Application of VADER filtering and empirical variance-covariance estimation.
Transformation of gravity coefficients to gridded surface mass anomalies using load Love numbers.
Substitution of low-degree terms (C00 and C20) with values from ESM2.0 HIS and SLR-like data.
Correction of GIA trends for Level 3 products using high-resolution ESM-derived GIA estimates.

All data are provided with clearly defined metadata and follow consistent naming conventions. The products enable quantitative assessment of the impact of mission design choices and data processing methods on gravity field retrieval performance.

Data access : The simulated gravity field data products are available through the ISDC Data Portal of the GFZ German Research Centre for Geosciences at https://isdc-data.gfz.de/. The specific dataset can be accessed directly via the following DOI: https://doi.org/10.5880/fidgeo.2026.049

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