Speaker: Mattthew McKinney
Insitution: UCLA Department of Atmospheric & Oceanic Sciences
We use an Earth-based climate model to explore the range of possible climate states between the Earth and Titan archetypes, and identify how changing basic planetary parameters moves a climate closer to one or the other. Venus, Earth, and Mars traditionally represent three archetypes of terrestrial planetary climates. Venus is blisteringly hot with a thick CO2 atmosphere and no surface water. Earth is much cooler, allowing for large global oceans and a moist atmosphere dominated by N2. Mars is frigid and dry, with its small reservoir of surface water locked up in ice at its poles. These three archetypes can be used to explore the range of possible climate states for a terrestrial planet, but do we have any other examples to include? Introducing the fourth terrestrial climate archetype: Titan. Saturn's largest moon, Titan, has an Earth-like volatile cycle, but with methane playing the role of water. We conduct experiments with an idealized, clear-sky GCM with water-vapor feedback by varying rotation rate, water volatility, and fractional land coverage and test them against three criteria based on observations of Titan's methane hydroclimate. We find that the volatility of the condensable plays a leading role in establishing a Titan-like climate. In this talk I will give a summary of these results and outline our future goals for this project.