A high resolution Mars surface gravity grid

Abstract

We have developed a new model of the gravitational acceleration vector at the surface of Mars, and present it on an equal area grid covering the surface of Mars, with a 1.73 km resolution. The long wavelength part of the model is adopted from MRO120d, which is a spherical harmonic model of the potential derived from Doppler tracking data of spacecraft in orbit about Mars. The short wavelength part is derived from convolution of appropriate Green's functions with the surface mass distribution associated with the MOLA topography, assuming a uniform mass density. The density was selected to be 2782kg/m3, which yields surface gravity values, from that approach, which match those from the spacecraft-derived model at the transition wavelength, which is taken to be degree 80. Our estimate of the error in the radial component is 11 mGal, with a larger contribution from long wavelength sources than from short wavelengths.