“…This corresponds to an area of $10 million km 2 , which is roughly the area of the United States, and a volume of sand-sized sediments that approaches $2.5 Â 10 5 km 3 , assuming 100 m-high dunes, clear-of-sand interdunes and an equal areal coverage between dunes and interdunes. More accurately, accounting for the variability in dune height (30-180 m, Barnes et al, 2008;Neish et al, 2010) and dune/interdune coverage fraction (35-60% as derived from Savage and Radebaugh (2011)) and considering a maximum thickness for the interdune sand cover of 5 m, we find that the volume of sediments in the dune fields should be within the range 0.5-5 Â 10 5 km 3 which represent an equivalent layer of $0.6-6 m. The sand budget is therefore most probably higher than the volume of liquid hydrocarbons on Titan which is currently estimated to be $0.3 Â 10 5 km 3 , accounting for the up-to-date distribution of the lakes and seas, assuming a conservative depth of 20 m (as proposed by Lorenz et al (2008)) and neglecting a potential subsurface reservoir.…”