National Aeronautics and Space Administration Logo
Follow this link to skip to the main content NASA Banner
Solar System Exploration
Science & Technology
Topography of Titan's Arctic Lake District: Implications for Subsurface Liquid Alkane Flow

NASA Science Highlight: Planetary Program Support


Research by K. L. Mitchell1, B. W. Stiles, C. Veeramachaneni, A. Hayes, R. L. Kirk, J. Andrews-Hanna, R. D. Lorenz, E. R. Stofan

Overlapping Titan RADAR Imagery of Arctic Lake District, Calibrated from Multiple Flybys
Overlapping Titan RADAR Imagery of Arctic Lake District, Calibrated from Multiple Flybys

By comparing the calibration of various overlapping Titan RADAR imagery, scientists on the Cassini RADAR instrument team were able to test a new model which is better able to estimate surface heights, elevations and subsurface phenomena within Titan's Arctic lake district. Because of the RADAR instrument's multi-beam nature, they were able to use the "SAR Monopulse Amplitude Comparison Method", which utilized the entire Arctic SARTopo database, derived from RADAR scenes of Cassini's Titan flybys T16, 18, 19, 25, 28, 29 and 30. The result has been the development of the "SARTopo" product which supplements the scant altimetry coverage of Titan with data that are conveniently located with SAR footprints.

Stereo Digital Terrain Model (DTM) of Arctic Lakes of Titan
Stereo Digital Terrain Model (DTM) of Arctic Lakes of Titan

Results: Upon reviewing the data used in this method, Titan lakes and seas appear not to exist on a simple equipotential surface, but the elevation distribution does appear to follow the level of the surrounding terrain, which is sloped down toward the main seas. Lakes and surrounding terrain tend to exhibit greater elevations in the western hemisphere (0-180 W) than in the eastern (180 - 360 W). Higher elevations correlate with small, rimmed lakes, and lower elevations with more diffuse seas. All but 3 of 39 lake samples are at elevations below that of their surroundings, lending credence to the method. The three exceptions were in SAR-dark expanses of sea, close to the noise floor. There is also a generally good correlation with stereo-derived DTM (in Figure 2, above). Two of the 39 lake samples are unexpectedly low in elevation. Both are internal to large expanses of fluids and so may represent similar non-physical results to those described above.

RADAR Image of Titan's Arctic Lake District
RADAR Image of Titan's Arctic Lake District

Implications:

The good correlation of SARTopo intra-lake lows (<100 m) with those in the T25-T28 stereo-derived DTM (Fig. 2; [5]) leads to the tentative conclusion that bathymetric (lake bottom) returns can be seen with this model, which improves understanding of Titan's subsurface phenomena.

Significance to Solar System Exploration:

By comparing the calibration of various overlapping Titan RADAR imagery, scientists can get better data sets, to more accurately measure elevations, subsurface flows and features of Titan.

Last Updated: 21 January 2014

Science Features
Astrobiology
Astronomy Features
Power
Technology Assessment Reports
Sungrazing Comets

 

Best of NASA Science
NASA Science Highlights
Technology Features
Propulsion
Lectures & Discussions

Awards and Recognition   Solar System Exploration Roadmap   Contact Us   Site Map   Print This Page
NASA Official: Kristen Erickson
Advisory: Dr. James Green, Director of Planetary Science
Outreach Manager: Alice Wessen
Curator/Editor: Phil Davis
Science Writer: Autumn Burdick
Producer: Greg Baerg
Webmaster: David Martin
> NASA Science Mission Directorate
> Budgets, Strategic Plans and Accountability Reports
> Equal Employment Opportunity Data
   Posted Pursuant to the No Fear Act
> Information-Dissemination Policies and Inventories
> Freedom of Information Act
> Privacy Policy & Important Notices
> Inspector General Hotline
> Office of the Inspector General
> NASA Communications Policy
> USA.gov
> ExpectMore.gov
> NASA Advisory Council
> Open Government at NASA
Last Updated: 21 Jan 2014