Séminaire
From Titan's Seas to Mars' Ice Caps: Analysis and Interpretation of Bistatic and Radar Sounding Data
Giancorrado Brighi
LATMOS seminar.
Description
Planetary radars have long been used to explore the surfaces and subsurfaces of worlds across the Solar System, from Mars and the Moon to icy satellites, comets and asteroids. Increasingly sophisticated radar instruments have provided, and continue to provide, unique insights into planetary environments, their formation, climate evolution and internal structure. In this seminar, I explore two radar datasets collected by means of very different radar techniques: bistatic radar experiments from the Cassini mission at Titan and radar sounding observations from the SHARAD instrument onboard the Mars Reconnaissance Orbiter.
First, I present results from the Cassini bistatic radar campaign at Titan, which targeted both solid terrains and the moon’s polar hydrocarbon seas. In particular, the analysis of bistatic echoes recorded at Earth-based stations places new constraints on surface state and composition of Titan’s major northern seas, Ligeia, Kraken and Punga Mare, as well as a few smaller lakes of the Northern Lake District. Sparser returns from solid surfaces provide information on the centimeter- to meter-scale planet roughness and on materials exposed at the moon’s surface.
Second, I address a long-standing puzzle in SHARAD observations of Mars’ south polar cap, where radargrams are dominated by a diffuse “fog” rather than the prominent bright reflectors seen in the north. While this phenomenon is generally attributed to surface roughness and/or volume scattering, I use electromagnetic scattering models to show that it may instead arise from densely packed, thin or low-dust-content layers generating specular reflections.
Both research projects have been developed during my PhD. Beyond addressing compelling scientific questions regarding Titan and Mars, they contribute more broadly to radar-based planetary exploration and highlight both the power and the complementary nature of these two radar techniques in probing planetary environments.
Giancorrado Brighi, LATMOS.
Informations supplémentaires
Location
LATMOS
Guyancourt
Room 2202
