The Bathymetry and Composition of Titan’s Lakes and Seas

Abstract

International audienceDespite pre-launch predictions that hydrocarbon liquids would be transparent to Cassini's 13.8 GHz radar [1] and that the radar's altimetry mode might be used as a sounder to probe Titan's liquids [2], experiments using liquefied natural gas by Paillou et al. [3] suggested that penetration would be significantly shallower than the altimeter's 35 m range resolution. Nevertheless, Mastrogiuseppe et al. [4] successfully detected subsurface reflections in altimetry echoes acquired over Ligeia Mare in May 2013 (Figure 1). Coherent processing of these echoes revealed the bottom reflection and allowed construction of a bathyme-try profile as well as an estimation of the liquid loss tangent from the relative variation in subsurface power. Subsequent altimetry observations of Kraken and Punga Maria obtained in August 2014 and January 2015, respectively, also showed detectable subsurface echoes. After applying these new techniques, subsur-face echoes were also observed in altimetry data acquired over Ontario Lacus in 2008. In this proceeding, we will report on the latest results from the analyses of these altimetry passe