MARSIS/Mars Express radar data processing and analysis.

• Main Author: Mouginot, Jérémie
• Other Authors: Laboratoire de Planétologie de Grenoble (LPG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Université Joseph-Fourier - Grenoble I, Wlodek Kofman([e-mail])
• Format: Doctoral or Postdoctoral Thesis
• Language: French
• Published: HAL CCSD 2008
• Subjects: Sounder radar; Martian Caps; Surface reflectivity; radar sounding; remote sensing; Radar sondeur; MARSIS; Mars; Calotte martienne; réflectivité surface; sondage radar; ionosphère; traitement du signal; [SDU]Sciences of the Universe [physics]; Ice; permafrost
• Online Access: https://theses.hal.science/tel-00364323; https://theses.hal.science/tel-00364323/document; https://theses.hal.science/tel-00364323/file/These_total_117_118_bis.pdf

This manuscript describes the data processing and analysis of the Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS). The data processing consists mainly to compensate the ionospheric distorsion. This correction provides as beneficial by-product to estimate the total electron content of the martian ionosphere. Using this results, we study in detail the martian ionosphere. We show that the remnant magnetic fied changes the spatial distribution of electrons in the ionosphere by accelerated the solar wind particles along magnetic field lines. The corrected radargrams provide the opportunity to study in detail the martian polar deposits. After the development of numerical tools to select the subsurface interfaces, we make a volume balance of the martian polar deposits. We show that the volume of the martian ice sheets is equivalent to a global water layer thickness of about 20 m. In a last part, we study the martian surface reflectivity. To do that, we extract the surface echo amplitude from each MARSIS pulse, and then, after calibrate it, we construct a global map of radar reflectivity (radar albedo). We describe the reflectivity map, firstly in a global point of view and secondly, more regionally around Medusae Fossae and the south residual cap of Mars. We show that the reflectivity decreases with the latitude, this constatation is probably linked to the presence of permafrost in the shallow subsurface. Near equator, we observe that the Medusae Fossae Formation corresponds to a dielectric constant of 2,4+/-0.5, which is carateristic of a porous and/or ice rich terrain. In the same region, we show that the dielectric constant of Elysium and Amazonis Planitia is equal to 7+/-1 and we observe a interface at about 140+/-20 m under the surface, our main conclusion is that these results are characterics of lava floods. Finally, the study of the reflectivity of south residual of Mars by a multi-layers model of reflectivity, shows that the CO2 layer covering this region has a thickness of about 11+/-1.5 ...