[X] My Assistant

[volcanopele]

The latest issue of Science has hit the web, and it contains an article by Lorenz et al. on the Great dune seas of Titan, as seen in T8 RADAR data:

http://www.sciencemag.org/cgi/content/abstract/312/5774/724

The article characterizes the longitundinal dunes seen in the equatorial dark regions and compares them to those seen in the Namib desert in southwestern Africa.

[volcanopele]

A giant chunk of the T8 RADAR SAR swath has been released on the planetary photojournal: http://photojournal.jpl.nasa.gov/catalog/PIA08454 . This is the largest contingous chunk of SAR swath ever released, AFAIK. This portion covers the dark region known as Belet. This dark region is covered in longitundinal sand dunes with the occasional hilly splotch to divert the dunes. On the right side of the swath is the western portion of Adiri.

[David]

A giant chunk of the T8 RADAR SAR swath has been released on the planetary photojournal: http://photojournal.jpl.nasa.gov/catalog/PIA08454 . This is the largest contingous chunk of SAR swath ever released, AFAIK. This portion covers the dark region known as Belet. This dark region is covered in longitundinal sand dunes with the occasional hilly splotch to divert the dunes. On the right side of the swath is the western portion of Adiri.

It reminds me of a Zen rock garden, the sand neatly raked in symmetrical rows, every once in a while broken by an irregular rock that the rows have to divert around.

It seems that Titan has both "wet" and "dry" zones -- the former being where we have extensive channelling (and so presumably either upwelling or downpour of liquids) -- and the latter being the dunes and other terrain lacking channels.

I note on the extreme right of this swath what looks to me like extensive cratering -- extensive for Titan, that is. I believe I also see traces of cratering in the Dune Sea at the left end of the swath, lighter colored rings or arcs. But the dunes cut right through them, suggesting to me that the craters are pretty much covered over -- probably invisible from the surface -- and that the dune-formation processes have been active in the relatively recent past. For the most part the Dune Sea shows no cratering at all.

My question is whether we know enough, yet, about the distribution of the wet and dry zones to form a hypothesis about why they are where they are? Obviously, much of the equatorial region is "dry", and yet Huygens found extensive small-scale channeling going on even there.