Climate Modeling of the Terrestrial Planets (and one Moon)

Venus, Earth, Mars, and Titan form a family of objects with relatively thick atmospheres overlying rocky surfaces. Comparative study of these objects allows access to a range of atmospheric and climate dynamics regimes that Earth by itself does not provide. The planets serve as rich and informative experiments and tests of our theoretical understanding over a wide range of conditions that can't be reproduced in the laboratory or field. In addition, detailed understanding of the processes operative in the modern climates of these bodies should improve reconstruction of past climates, which is often of greater interest to those outside of the atmospheric community. The family of "terrestrial atmospheres" inhabits a relatively broad range of parameter space, from fast rotating Earth and Mars to the extremely long Venusian day, from the roughly 2 day radiative timescale of Mars to the roughly 100 year timescale for Venus, and from temperatures hot enough to permit transition metal ore frost on Venus to those cold enough for methane and carbon dioxide to act as volatiles on respectively Titan and Mars. Despite this, all of the members of this family are amenable to study with suitably adapted versions of the three-dimensional General Circulation Model / climate modeling systems developed for the Earth. In this presentation, we describe the application of GCMs based on the NCAR global WRF (grid point) and CAM (spectral and finite volume) models to each of the planets of this family. Examples of our application of these models include the superrotation of the atmospheres of Venus and Titan; Methane cycling in Titan's atmosphere, including rainfall and patterns of aridity; Carbon dioxide and water cycles on Mars; and the cycle of Martian aerosol dust.