Rocky Planet Habitability: Insights from Solar System Climate Dynamics Through Time

I will contribute to the project Rocky Planet Habitability: Insights from Solar System Climate Dynamics Through Time by doing theoretical modeling related to the climate evolution of the planet Venus, and its application to the wider question of exoplanet climate evolution and habitability.  This is part of a 5 year, multi-investigator, multi-institutional 3-D modeling approach to understand the habitability of Solar System rocky planets through time, and to inform the detection and characterization of habitable exoplanets in the future.  I will perform 1-D models of the atmosphere of Venus. The results will be used to drive 3-D simulations of planetary climates with a generalized General Circulation Model (GCM).  The 1-D radiative-convective model employed for this study is the same one used to treat the recent evolution of Venus climate, forced by volcanism consistent with the geologic record shown by Magellan (Bullock and Grinspoon 2001).  1-D models can simulate the long-term evolution of Venus’ climate and define time slices for GCM studies. The Bullock and Grinspoon (2001) models were run to radiative-convective equilibrium at each time step, altering the composition due to escape, volcanism, and geochemistry and self-consistently constructing the resulting cloud and temperature profiles. In this way, the behavior due to changing insolation and endogenous processes was calculated for up to 1 Gyr in 1 Myr steps. We will use this 1-D model to explore the approach to a runaway state for early Venus and for hypothetical exoplanets (Section 3.3.d) and to initialize GCM runs. Our 1-D models close to the onset of a water vapor runaway will be used to identify a set of states that will be explored with ROCKE-3D model. We will perform a series of GCM studies using early Venus as a baseline to assess the role that volcanic input to the atmosphere, atmospheric dynamics at different rotation rates, different ocean depths, variable cloudiness, and the presence of life may play in extending the lifetime of oceans on exoplanets near the inner edge of the habitable zone.