This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).
Saturn's largest moon, Titan, is perhaps the only other body in the solar system currently experiencing the familiar atmospheric processes of precipitation, liquid and aeolian erosion, and the formation and dissipation of smog-like haze. This project will resolve several outstanding questions about Titan, such as the source of the atmospheric methane (which should survive for tens of millions of years without being replenished), why clouds appear over specific latitude ranges at certain times, and how the haze migrates between north and south hemispheres.
The project has five goals: 1) investigate whether localized sources of methane can be detected from maps of Titan; 2) characterize the conditions for methane condensation as a function of time, latitude and altitude; 3) compare the predictions of the Titan Regional Atmospheric Modeling System (TRAMS) with high-resolution image sequences of convective clouds; 4) investigate if there is such a phenomenon as "morning brightening", a diurnal asymmetry in the east/west limb brightnesses; 5) map the latitudinal and height distributions of haze from 1996 through 2007. The study applies constraints on the properties of Titan's atmosphere and its methane clouds which come from Cassini Spacecraft data, Hubble Space Telescope observations, and ground-based Keck images, interpreted in part with TRAMS. The analysis will include the construction of three-dimensional hemispherical maps of methane and haze profiles, the determination of temperature profiles from spectra obtained with the Cassini Composite Infrared Spectrometer, and a study of clouds in Cassini Imaging Science Subsystem image sequences to determine the scale and lifetime of convective cloud components.
Because similar processes are operating on Earth, Titan is an important laboratory for investigating familiar processes like precipitation, erosion, and the properties of smog-like hazes. The project will also support summer undergraduate students at the University of Idaho who will assist and be trained in astronomical data processing. The work supports an additional postdoctoral scholar at the University of Maryland.
