Theses and Dissertations Collection

In this thesis, I investigate the occurrence of sun glitter and waves on the sea surfacesof Titan’s northern seas, Kraken Mare and Punga Mare. These studies of various sun glitter features help to uncover unique liquid bodies, such as liquid-filled channels, better understand the dynamics behind the air-sea-land interactions during the northern summer. Some of these interactions include wind-generated capillary waves, tidal currents, and wave shoaling. In Chapter 1, I introduce the physics of sunglint and sun glitter observations in a terrestrial context and elaborate on the spacecraft geometry that necessitates a sun glitter observation on Titan. In addition, I provide an overview of prior specular observations from the seas on Titan and the geographical context for Titan’s seas. In Chapter 2, I present Cassini VIMS observations of sun glitter – wave-induced reflections from a liquid surface offset from a specular point – on Kraken Mare. Sun glitter reveals rough sea surfaces around Kraken Mare, namely the coasts and narrow straits. The sun glitter observations indicate wave activity driven by the winds and tidal currents in Kraken Mare during northern summer. T104 Cassini VIMS observations show three sun glitter features in Bayta Fretum indicative of variegated wave fields. I cannot uniquely determine one source for the coastal Bayta waves, but I lean toward the interpretation of surface winds, because tidal currents should be too weak to generate capillary-gravity waves in Bayta Fretum. T105 and T110 observations reveal wave fields in the straits of Seldon Fretum, Lulworth Sinus, and Tunu Sinus that likely originate from the constriction of tidal currents. Coastlines of Bermoothes and Hufaidh Insulae adjoin rough sea surfaces, suggesting a complex interplay of windroughened seas and localized tidal currents. Bermoothes and Hufaidh Insulae may share characteristics of either the Torres Strait off Australia or the Åland region of Finland, summarized as an island-dense strait with shallow bathymetry that hosts complex surface circulation patterns. Hufaidh Insulae could host seafloor bedforms formed by tidal currents with an abundant sediment supply, similar to the Torres Strait. The coastlines of Hufaidh and Bermoothes Insulae likely host ria or flooded coastal inlets, suggesting the Insulae may be local peaks of primordial crust isolated by an episode of sea-level rise or tectonic uplift. In Chapter 3, I present new evidence for active coastal and oceanic features in Titan’s Punga Mare observed in a high-phase Cassini VIMS observation of sunglint from the T110 flyby. I observe sunglint in a river, Apanohuaya Flumen, resulting from differing pixel contributions of land adjacent to the channel and implying smooth liquid surfaces. Along the eastern coastline, I identify a 5-m-bright margin. A possible explanation for this brightening may include a coastal margin of rough seas. I find evidence of variegated sea surface roughness in Fundy Sinus and isolated sun glitter near Hawaiki Insulae that suggests seasonal interactions between surface winds and topography. RADAR observations of debouches (where rivers meet bays) within Punga Mare overlap several bright 5 m pixels that indicate rough liquid surfaces. We postulate that a change in liquid flow regimes, possibly occurring as surface streamflow, or bubble outburst events may be responsible for surface roughness near these debouches. These observations imply air-sea-land interactions and hydrological activity are present in Titan’s sea district during the northern summer. In Chapter 4, I summarize the implications of the various sun glitter observations on Titan oceanography.