The Climate of Early Mars: New Investigations into a Long-standing Problem
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Dr. Robin Wordsworth
Assistant Professor
Harvard School of Engineering and Applied Sciences
The nature of the early Martian climate is one of the great remaining mysteries of planetary science. Evidence for flowing liquid water on the surface 3-4 Ga is conclusive, but whether this was due to long-term warm and wet conditions or episodic processes remains unclear. Here I describe our recent progress on this problem. I begin by discussing a 3D climate model we have developed that simulates dense gas radiative transfer accurately and includes a self-consistent hydrological cycle. Based on the model results, I argue that an epsiodically warm, 'icy highlands' scenario for the early climate provides a better fit to the geological evidence than continuously warm and wet conditions. I then discuss plausible warming mechanisms. Based on recent spectroscopic and line-by-line radiative transfer calculations we have performed, I suggest that transient release of reducing gases (CH4 and H2) into a CO2-dominated atmosphere provides the most viable solution to the martian faint young Sun problem. Implications for habitability and pre-biotic chemistry will also be discussed.
Host: Dr. Roger Yelle