# EGM2008 Gravity Anomalies and DOV Data

*Introduction*

*Introduction*

The official Earth Gravitational Model EGM2008 has been publicly released by the NGA EGM Development Team. This gravitational model is complete to spherical harmonic degree and order 2159, and contains additional coefficients extending to degree 2190 and order 2159.

This page contains data files of Free-Air Gravity Anomalies and Deflections of the Vertical (DOV) computed from EGM2008. All computations were performed using the **Tide-Free** version of EGM2008 to degree 2190. The **WGS 84 Geodetic Reference System (GRS)** was used to define the geometry and the normal gravitational potential of the reference ellipsoid. The computed values refer to the surface of this reference ellipsoid. These data files were computed on a SUN computer, which uses a **BIG ENDIAN** internal binary representation. For further details and statistics of the data, please see the README file.

Also, before using any of the data files on this web page, please read the disclaimer.

### Free-Air Gravity Anomalies and Deflections Of the Vertical Data

Point Values on a Global 2.5 x 2.5-Minute Grid

- README Describing EGM2008 Free-Air Gravity Anomaly and DOV Data Files (README_FIRST_new.pdf)
- 2.5 x 2.5-Minute Free-Air Gravity Anomaly Grid (Dg01_cnt2.5x2.5_EGM08_to2190_WGS84_ell_nh - 145 MB) - Global grid of point values of free-air gravity anomalies in mGal.
- 2.5 x 2.5-Minute DOV Meridional Component (xi) Grid (xi_cnt2.5x2.5_EGM08_to2190_WGS84_ell_nh - 145 MB) - Global grid of point values of the meridional component (xi) of the DOV in arc-seconds.
- 2.5 x 2.5-Minute DOV Prime Vertical Component (eta) Grid (eta_cnt2.5x2.5_EGM08_to2190_WGS84_ell_nh - 145 MB) - Global grid of point values of the prime vertical component (eta) of the DOV in arc-seconds.
- Program to Read 2.5-Minute Gravity Anomaly and DOV Grids (read_3files_min2.5 - 7 KB) - FORTRAN program that can be used to read the free-air gravity anomaly and DOV grids above.
- Output from the Program Above (read_3files_min2.5.out01 - 12 KB) - Contains a sample output from a run of the program above.

Area-Mean Values of Free-Air Gravity Anomalies on a Global 5 x 5-Minute Grid

- 5 x 5-Minute Area-Mean Free-Air Gravity Anomaly Grid (Dg01_mean5.0x5.0_EGM08_to2190_WGS84_ell_nh - 36 MB) - Global grid of area-mean values of free-air gravity anomalies in mGal.
- Program to Read 5-Minute Gravity Anomaly Grid (read_1file_min5.0 - 6 KB) - FORTRAN program that can be used to read the area-mean free-air gravity anomaly grid above.
- Output from the Program Above (read_1file_min5.0.out01 - 7 KB) - Contains a sample output from a run of the program above.

### Additional Information

- The development and evaluation of the Earth Gravitational Model 2008 (EGM2008) - Nikolaos K. Pavlis, Simon A. Holmes, Steve C. Kenyon, John K. Factor; Journal of Geophysical Research: Solid Earth (1978-2012) Volume 117, Issue B4, April 2012
- EGM2008 JGR Erratum
- An Earth Gravitational Model to Degree 2160: EGM2008 (NPavlis&al_EGU2008.ppt - 18.5 MB) - Presentation given at the 2008 European Geosciences Union General Assembly held in Vienna, Austria, April13-18, 2008.
- Background Papers from Earlier Symposiums on the New EGM

**Please provide comments, suggestions, and feedback to the contacts below as we strive to improve our EGM2008 products. Thank you!**

Dr. Nikolaos Pavlis NGA, Geodesy and Geophysics Basic and Applied Research wgs84@nga.mil Nikolaos.K.Pavlis@nga.mil |
NGA Office of Geomatics (SN) EGM2008 Development Team wgs84@nga.mil |

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