We propose to develop fundamental new insights into how methane flows through titan s atmosphere and surface (hereafter methane hydrology ), how these processes are expressed in the observed cloud…

This federal contract award, with identification number NNX16AI44G, was granted by the National Aeronautics and Space Administration (NASA) to the University of California, Los Angeles (UCLA) to develop new insights into the methane hydrology of Titan, Saturn's largest moon. The primary objectives are to explore how Titan's surface features influence atmospheric phenomena, and to use Cassini spacecraft observations to understand the fate of precipitation and the signatures of evaporation on Titan's surface. The $388,656.94 grant does not have a set-aside designation and will leverage UCLA's expertise, as well as collaboration with Cassini team members, to advance the understanding of Titan's climate, weather, and methane cycle. The parent organization for UCLA is the State of California Controller's Office, which has also received federal contract and grant awards in support of various government initiatives.

We propose to develop fundamental new insights into how methane flows through titan s atmosphere and surface (hereafter methane hydrology ), how these processes are expressed in the observed cloud distribution and methane concentrations in the atmosphere and observed morphologies and spectral properties of its surface, and how all of this might have changed through time. Our primary motivation arises from the vast array of cassini and ground-based observations of titan s atmospheric methane concentration ( d mkovics ET AL. 2015) and clouds (rodriguez ET AL. 2009; turtle ET AL. 2011), fluvial erosional features and deposits (tomasko ET AL. 2005; soderblom ET AL. 2007; burr ET AL. 2013; perron ET AL. 2006; langhans ET AL. 2012), and spectral (barnes ET AL. 2011; griffith ET AL. 2012; mackenzie ET AL. 2014) and topographic (lorenz ET AL. 2013; hayes, submitted) inhomogeneities of the surface. The SUM of these observations reveal a world with striking similarities to our own: vast zones of both dry and wet surface conditions; a surface carved by the flow of liquids; river channels flowing into large lakes (both filled and empty); a pronounced seasonal cycle in the location and timing of storms; and residues left behind after the methane has evaporated and/or infiltrated away. Yet observations alone cannot tell the whole story of how titan s seasonal weather (which itself might change through time) interacts with the surface to produce these phenomena. Our primary proposed science objectives fit into two main categories. First, we propose to explore how the inhomogeneities of titan s topography, surface albedo, and surface heat capacity observed by cassini vims, radar and radio influence atmospheric phenomena modeled by the titan atmosphere model (TAM; lora ET AL. 2015) and/or observed by cassini vims and ISS, and ground-based instruments. Second, we propose to use cassini vims and radar observations of titan s lakes/seas, fluvial channels and evaporites to understand what controls the fate of precipitation, the potential influence of runoff, and the regional signatures of evaporation predicted by TAM coupled to a model of surface hydrology. In both tasks, we will leverage the unique and proven capabilities of TAM to simulate precipitating storms (mitchell & lora, submitted), while also extending TAM to be the first titan GCM to realistically model surface hydrology. These model innovations and the vast archive of new observations of titan s surface and atmosphere from cassini and ground-based instruments will allow US to provide fundamental, new insights into titan s methane hydrology. To achieve these science objectives, we have assembled a talented team of collaborators, who will provide expert advice in the development of the TAM surface hydrology scheme, and keen guidance on cassini and ground-based observations. In particular, our collaborators include cassini team members alex hayes (radar) and jason barnes (vims). Thus, through the combined efforts of the proposed TAM model development and skilled guidance into the observations, we propose to discover how precipitated methane flows over and through titan s surface, how this results in lakes, seas and fluvial channels, and how these surface features feedback on the observed atmospheric phenomena.