Cassini maps Titans vast dune fields that act like weather vanes

February 27th, 2009 - 6:32 pm ICT by ANI  

Washington, Feb 27 (ANI): Using four years of radar data collected by the Cassini spacecraft, scientists have mapped Titans vast dune fields, which may act like weather vanes to determine general wind direction on Saturns biggest moon.

Titans rippled dunes are generally oriented east-west. Surprisingly, their orientation and characteristics indicate that near the surface, Titans winds blow toward the east instead of toward the west.

This means that Titans surface winds blow opposite the direction suggested by previous global circulation models of Titan.

At Titan there are very few clouds, so determining which way the wind blows is not an easy thing, but by tracking the direction in which Titans sand dunes form, we get some insight into the global wind pattern, said Ralph Lorenz, Cassini radar scientist at Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland.

Think of the dunes sort of like a weather vane, pointing us to the direction the winds are blowing, he added.

According to Jani Radebaugh, Brigham Young University, Provo, Utah, Titans dunes are young, dynamic features that interact with topographic obstacles and give us clues about the wind regimes.

Winds come at these dunes from at least a couple of different directions, but then combine to create the overall dune orientation, Radebaugh said.

The wind pattern is important for planning future Titan explorations that might involve balloon-borne experiments.

Some 16,000 dune segments were mapped out from about 20 radar images, digitized and combined to produce the new map.

Titans dunes are believed to be made up of hydrocarbon sand grains likely derived from organic chemicals in Titans smoggy skies.

The dunes wrap around high terrain, which provides some idea of their height. They accumulate near the equator, and may pile up there because drier conditions allow for easy transport of the particles by the wind.

Titans higher latitudes contain lakes and may be wetter with more liquid hydrocarbons, not ideal conditions for creating dunes. (ANI)

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