Crustal density differences along Mars' dichotomy boundary from gravity and topography
Sander Goossens
We have applied a novel constraint in the analysis of spacecraft tracking data to determine Mars' gravity field that allows for the determination of the density of the north and south directly from the data. From this analysis we find a density of 2622 ± 42 kg m-3 for the north and 2492 ± 36 kg m-3 for the south. This result is independent from the seismic results, and consistent with seismic constraints that indicate the difference between the north and south should not be greater than 200 kg m-3.
Here, we present data sets from our analysis. These data sets are gravity field models of Mars that use our RM-S dichotomy constraint. We have determined several solutions using different constraint factors λ (see Goossens & Sabaka, 2025 for details) which are presented here. The format of these files is as follows:
- The first line contains the GM (m3/s2), reference radius (m), and maximum degree and order of the model.
- The following lines contain: degree l, order m, the coefficients Clm, Slm. The coefficients are 4π-normalized.
We also include two clone archives (see here for a description of what clone models are) for the models using λ=1016 and λ=1017. Clone models are statistically equivalent models generated from (a very good approximation) of the full covariance matrix and can be used to assess the influence of errors on the coefficients. These clone archives are presented as gzipped tar archives, with 100 clones each in the same format as the gravity field models.
Data
Spherical harmonics expansion of the martian gravity field based on the GMM-3 data matrix with the RM-S dichotomy constraint using λ=1012: downloadSpherical harmonics expansion of the martian gravity field based on the GMM-3 data matrix with the RM-S dichotomy constraint using λ=1013: download
Spherical harmonics expansion of the martian gravity field based on the GMM-3 data matrix with the RM-S dichotomy constraint using λ=1014: download
Spherical harmonics expansion of the martian gravity field based on the GMM-3 data matrix with the RM-S dichotomy constraint using λ=1015: download
Spherical harmonics expansion of the martian gravity field based on the GMM-3 data matrix with the RM-S dichotomy constraint using λ=1016: download
Spherical harmonics expansion of the martian gravity field based on the GMM-3 data matrix with the RM-S dichotomy constraint using λ=1017: download
Spherical harmonics expansion of the martian gravity field based on the GMM-3 data matrix with the RM-S dichotomy constraint using λ=1018: download
Spherical harmonics expansion of the martian gravity field based on the GMM-3 data matrix with the RM-S dichotomy constraint using λ=1019: download
Spherical harmonics expansion of the martian gravity field based on the GMM-3 data matrix with the RM-S dichotomy constraint using λ=1020: download
Spherical harmonics expansion of the martian gravity field based on the GMM-3 data matrix with the RM-S dichotomy constraint using λ=1021: download
Spherical harmonics expansion of the martian gravity field based on the GMM-3 data matrix with the RM-S dichotomy constraint using λ=1022: download
Spherical harmonics expansion of the martian gravity field based on the GMM-3 data matrix with the RM-S dichotomy constraint using λ=1023: download
Spherical harmonics expansion of the martian gravity field based on the GMM-3 data matrix with the RM-S dichotomy constraint using λ=1024: download
Spherical harmonics expansion of the martian gravity field based on the GMM-3 data matrix with the RM-S dichotomy constraint using λ=1025: download
Spherical harmonics expansion of the martian gravity field based on the GMM-3 data matrix with the RM-S dichotomy constraint using λ=1026: download
Spherical harmonics expansion of the martian gravity field based on the GMM-3 data matrix with the RM-S dichotomy constraint using λ=1027: download
Clone archive for the model using λ=1016: download
Clone archive for the model using λ=1017: download
Data Usage Policy
Please cite the following reference when using any of the products described above:Manuscript: Goossens, S. and Sabaka, T.J. (2026), Crustal density differences along Mars' dichotomy boundary from gravity and topography, Geophysical Research Letters, doi:10.1029/2026GL122393.
Dataset: Goossens, S. and Sabaka, T.J. (2026), Crustal density differences along Mars' dichotomy boundary from gravity and topography [Data set]. NASA Goddard Space Flight Center Planetary Geodesy Data Archive. doi:10.60903/GSFCPGDA-MARS-RMS.