Longitudinal Dunes on Titan as Indicators of Regional and Local Winds

Details Longitudinal Dunes on Titan as Indicators of Regional and Local Winds Longitudinal Dunes on Titan as Indicators of Regional and Local Winds

Dec 2006

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2006agufm.p12a..03r&link_type=abstract

American Geophysical Union, Fall Meeting 2006, abstract #P12A-03

Other

5415 Erosion And Weathering, 5464 Remote Sensing, 5470 Surface Materials And Properties

Scientific paper

The Cassini Radar instrument has revealed the presence of thousands of longitudinal dunes across Saturn's moon, Titan. These have a generally W-E orientation and are found primarily within 20° of the equator (Lorenz et al. 2006). These have sizes and morphologies comparable to dunes found on Earth's Namibian desert, with widths of 1-2 km, heights of ~100 m, and lengths from <5 km to nearly 150 km. They are radar-dark, which is attributed not simply to radar shadowing but to being composed of materials that do not strongly scatter at the 2.18 cm wavelength of the radar instrument. The most likely composition is that of some combination of loosely consolidated hydrocarbon particulates and erosion-produced water ice particles. The formation of longitudinal dunes requires that winds strike the long axis of the dunes obliquely from basically two main directions at different times (Tsoar, 1983), so this atmospheric condition, possibly influenced by tides (Tokano et al., 2001), must exist at Titan's surface. We explore localized groupings of dune orientations, both the width of a radar swath (over 140° longitude) and smaller (~10° x 10°) areas in the hopes that the work will contribute to further constraining wind or atmospheric circulation patterns. Unobstructed dunes, such as those found in the T8 swath, covering 180°- 320° W longitude near the equator, have mean orientations of 80° from N. On a local scale, mountain blocks and other high elevation features divert these dunes, causing their orientations to vary, and revealing a local change in wind direction. Large, regional, land masses also appear to have an effect on dune orientations, on a nearly hemispheric scale. Dunes north of Xanadu, found in the T3 swath (0° - 140° W longitude), have a higher variation in orientation and appear to divert around Xanadu. Similar diversion patterns are seen in dunes found on the western end of the T13 swath (which passed directly over Xanadu) that have orientations of 109°. This work can help constrain GCM models of wind circulation patterns by providing time-averaged data on a regional scale. Smaller-scale variations in dune orientations can be indicators of local changes in wind patterns and velocities, for example, as with those due to topography. Dune groupings may be good indicators of local topographic lows, if particles collect in basin-like areas. Initial observations of these groupings are consistent with that prediction. The authors acknowledge the Cassini project and, especially, the highly successful Cassini spacecraft and radar instrument.

Affiliated with

Also associated with

No associations

Rating

Longitudinal Dunes on Titan as Indicators of Regional and Local Winds does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Longitudinal Dunes on Titan as Indicators of Regional and Local Winds, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Longitudinal Dunes on Titan as Indicators of Regional and Local Winds will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-960875