Availability of the EGM96 Surface Gravity Data


Availability of the Surface gravity Data used in EGM96

Gravity Anomaly Data

The gravity anomaly data files used in the development of EGM96 are available from the following sources via anonymous FTP:

Four files containing gravity anomaly data are provided:
NIMA_V060796_ALT_MIN30.DT2 (Altimetry 30' values from NIMA).
NIMA_V091296_TERR.MIN30 (Terrestrial 30' values from NIMA).
OSU_V072189_TERR.MIN30_MOD (Terrestrial 30' values from OSU).
NIMA_V091296_TERR.DEG01 (Terrestrial 1 deg. values from NIMA).

In addition, a file containing harmonic coefficients of the potential is provided. These coefficients may be used to derive "fill-in" values for areas void of any other type of gravity anomaly information. This file is called:


The documentation describing these files is provided in two forms:
docum_gravity_data.mac_word5.1 (Macintosh WORD 5.1 format).
docum_gravity_data.PS (PostScript format).

Please ftp the documentation files first. The data files are ASCII and instructions on how to read and interpret the information is given in the documentation files.

If you are unable to 'translate' either format of the documentation files please send e-mail to:


or flemoine@ares.gsfc.nasa.gov

Include your complete address in your message. A hard copy of the documentation will be faxed or mailed to you.

Source Codes for Final Merged Surface Gravity File

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Send questions or comments to:
Frank.G.Lemoine@nasa.gov or Nikolaos.Pavlis@raytheon.com