Constraining Waves on Titan's Northern Lake Jingpo Lacus using VIMS Specular Reflection Observations

Abstract

Using the specular reflection discovered in T58 Cassini-VIMS data by Stephan et al. (2010), we analyzed the resulting photometric lightcurve of this specular event to constrain wave activity. Waves spread out the specular reflective intensity on the surface of the liquid. Without waves, the intensity distribution would represent a perfect image of the Sun. Since VIMS does not spatially resolve the specular intensity distrubution, we use the specular intensity's evolution over time to infer its properties instead. A specular intensity distribution spread out by wave activity will rise and diminish slowly upon a transition from land to sea or sea to land respectively. Without waves, the intensity will rapidly wink on and off as the specular point crosses the shoreline. We find that the waves on Jingpo Lacus, an Ontario Lacus-sized lake in Titan's north near Kraken Mare, cannot have slopes of more than 0.2 degrees. A specular reflection lightcurve of Kraken Mare itself from T59 is harder to interpret, showing variability that could be either atmospheric scintillation, clouds, changing wind conditions, or kilometer-wavelength waves.