EGM2020

EGM2020, or the Earth Gravitational Model 2020, is a global representation of Earth’s gravity field published in 2020. It provides a high-resolution spherical harmonic expansion of the Earth’s gravitational potential and is used for precise geodesy, satellite orbit determinations, and related applications. EGM2020 supersedes the earlier EGM2008 model by incorporating newer data and methods to improve accuracy, especially in regions previously undersampled.

Development and data sources: The model was produced by the National Geospatial-Intelligence Agency (NGA) with contributions from international partners and researchers. It integrates satellite gravity data from missions such as GRACE and GRACE-FO, GOCE, as well as extensive terrestrial gravity measurements and ocean altimetry. The combination of space- and ground-based data enhances both long-wavelength and short-wavelength components of the gravity field.

Format and resolution: The gravity field is expressed through a series of spherical harmonic coefficients up to a high degree and order, enabling detailed representation of gravity anomalies and geoid undulations worldwide. This high degree of resolution improves accuracy over previous global models, particularly in regions with dense data coverage and in coastal zones.

Applications: EGM2020 is widely used for precise orbit determination of spacecraft, GNSS-based positioning, and geoid and height system realizations. It also supports geophysical research into Earth’s interior and crustal structure, as well as oceanographic studies and sea-level research.

Access and documentation: The model, along with coefficient files, geoid grids, and accompanying documentation, is publicly available through NGA and affiliated institutions. Users are encouraged to consult official release notes for regional accuracy and applicability.

See also: EGM2008, geopotential models, geodesy, gravity field.