How can we image the interiors of polar ice caps on Mars from radar sounding observations?
The north and south polar layered deposits (NPLD, SPLD) on Mars describe ancient climate cycles through stratified layers of ice and dust, similar to how we can study climate change on Earth by taking ice cores from glaciers. The SHARAD and MARSIS orbital radar sounders have accumulated thousands of orbits worth of observations of the NPLD and SPLD. Typical 2D synthetic aperture radar processing of these data does not adequately capture the 3D interior structure of the NPLD and SPLD. In our work, we exploit state-of-the-art technology in terrestrial seismic imaging to produce 3D image volumes for the NPLD and SPLD from SHARAD and MARSIS radar sounding observations. The improvements in spatial resolution facilitated by our 3D processing provide new constraints on the state and evolution of ancient climate processes on Mars, which in turn informs the history and evolution of water and habitability. Depicted here is an illustration of redatuming SHARAD observations to MOLA-derived topography of Korolev crater using analytic Green’s functions, as well as an image of the NPLD, courtesy NASA/JPL-Caltech/MSSS.