geogravL3 1.2.2

Grace Level 3 Python package.

This package processes Earth gravity field data—provided as spherical harmonic coefficients—into gridded, domain-specific datasets. It also includes uncertainty estimation and the generation of regional mean time series.

License and Citation

geogravL3 is distributed under the GNU General Public License v3.0 or later (GPL-3.0-or-later).

When using the software, please cite:

Boergens, E., Rabe, D., Charly, A., Wilms, J., Scheffler, D. (2025): geogravL3 - a Python Package for Processing Earth Gravity Field Data. GFZ Data Services. https://doi.org/10.5880/GFZ.DQTO.2025.002

Documentation

The documentation with details on the installation, usage, and configuration can be found at https://grace_l3.git-pages.gfz-potsdam.de/geogravl3/doc/.

Description

geogravL3 provides the processing pipeline from Level-2 data (spherical harmonic coefficients) to domain-specific gridded Level-3 data and the computation of regional mean time series.

Input:

• Spherical harmonic coefficients, provided as one file per time step, in either ICGEM (*.gfc), YAML (without file ending), or SINEX format (*.snx).

• Configuration file steering the processing steps. Either in Json format (*.json) or XML format (*.xml).

Output

• NetCDF files (*.nc) per domain containing gridded data

• CSV files (*.csv) per domain containing mean regional time series

Processing Details

Details of the processing steps, or their omission, are govern by the configuration file. Details on the configuration file is provided at https://grace_l3.git-pages.gfz-potsdam.de/geogravl3/doc/config.html.

Domain-Independent Processing Steps

• Removal of the mean field

• Filtering of spherical harmonic coefficients: - DDK - Gaussian filter - VDK (requires SINEX input)

• Replacement of C20 and C30 with external data

• Subtraction of the GIA model

• Estimation and insertion of geocentre motion coefficients (C10, C11, S11)

• Subtraction of the 161-day aliased signal

Domain-Specific Processing Steps

Land — Terrestrial Water Storage (TWS)

• Spherical harmonic synthesis

• Masking of the ocean

• Uncertainty estimation based on open-ocean noise

Ocean — Ocean Bottom Pressure (OBP)

• Spherical harmonic synthesis (land and ocean domains only)

• Separation of the ocean signal into: - Barystatic sea level, estimated via the sea-level equation - Residual circulation

• Uncertainty estimation based on residual time-series signals

Ice Sheets — Greenland and Antarctica

• Gridded data estimated using the sensitivity-kernel approach

• Uncertainty estimation based on residual time-series signals

Status

See also the latest coverage report and the pytest HTML report.

History / Changelog

You can find the protocol of recent changes in the geogravL3 package here.

Credits

This software package was developed under ESA contract 4000145266/24/NL/SC – NGGM and MAGIC End-to-End Mission Performance Evaluation Study.

The scientific and methodological development was led by Eva Boergens ([e-mail]). Martin Horwath ([e-mail]) contributed the ice-processing methodology. A complete list of contributors—covering both software development and the heritage code that was translated into Python as part of this project—is available here.

The FERN.Lab ([e-mail]) contributed to the development, documentation, continuous integration, and testing of the package. This package was created using Cookiecutter and the fernlab/cookiecutter-py-package project template.