• Pettinelli, E.
• Gurnett, D.
• Piccari, F.
• Zampolini, E.
• Melacci, P.
• Nielsen, E.
• Bombaci, O.
• Jordan, R.
• Marinangeli, L.
• Federico, C.
• Flamini, E.
• Giuppi, Stefano
• Biccari, D.
• Cicchetti, A.
• Calabrese, D.
• Plaut, J.
• Huff, R.
• Seu, R.
• Edenhofer, P.
• Plettemeier, D.
• Kirchner, D.
• Johnson, W.
• Williams, I.
• Orosei, R.
• Safaeinili, A.
• Hagfors, T.
• Vannaroni, G.
• Frigeri, Alessandro
• Picardi, G.
• Marini, A.
• Cartacci, M.
• Noschese, Raffaella
• Masdea, A.

Abstract

An approach to the inversion of the data available from the MARSIS (Mars Advanced Radar for Subsurface and Ionosphere Sounding) instrument on Mars Express is described. The data inversion gives an estimation of the materials composing the different detected interfaces, including the impurity (inclusion) of the first layer, if any, and its percentage, by the evaluation of the values of the permittivity that would generate the observed radio echoes. The data inversion method is based on the analysis of the surface to subsurface power ratio and the relative time delay as measured by MARSIS. A volume scattering and a multilayer analysis has been performed in order to analyze the influence of these scattering process on the obtained results. The data inversion has been performed at several frequencies to estimate the frequency dependent parameters affecting the behaviour of the radar echoes. The main complexity, pertaining to the data inversion, is related to the accuracy needed on the values of the dielectric constant on the surface (∊'m(0)), as well as on the accuracy in the radar data influenced by various causes as, for instance, the ionosphere residual distortion. Taking into account that along the orbits the echo frames exhibit a non stationary behaviour, due to the shape of the surface and subsurface, in order to obtain a proper inversion, the frames have been selected only in regions of MARS that are moderately flat as can be determined, a priori, from MOLA data and by the echoes' behaviour. Few models of the subsurface has been considered and a list of inclusion material considered as end to end members of possible scenarios have been assumed....

Topics

• impedance spectroscopy
• surface
• inclusion
• dielectric constant