The New NASA Ames Mars Global Climate Model: Comparing a Reference Simulation to MRO/MCS Temperatures.

The new NASA Ames Mars Global Climate Model (GCM) is based on the NOAA/GFDL cubed-sphere finite volume (FV3) dynamical core. This core is highly scalable and parallelizable, which allows for high resolution simulations in the horizontal and the vertical. We have completed the porting and initial testing of Ames-developed Mars physics routines from the Legacy Mars GCM (Haberle et al., 2019; JGR, 333) into the new GCM to complement the Mars physics routines that previously existed in the NOAA/GFDL FV3-based Mars GCM. Our reference simulation is executed at a horizontal resolution of ~2x2 and extends to ~90 km. We use a background dust scenario, which is constructed from the dust scenarios of (Montabone et al., 2015; JGR, 125) by identifying the spatially and seasonally varying minimum value of the multiyear record (MY29-34) to filter out the influence of episodic regional dust storms. In the vertical, we fit a modified Conrath parameter (Forget et al. 1999; JGR, 104) to a spatially and temporally evolving simulated 3-D distribution that is constrained to follow the background column dust opacity scenario. We use a simple water ice cloud scheme (Wilson and Guzewich; GRL, 31), which allows for highly controlled cloud radiative effects. We will show comparisons between simulated and MRO/MCS-observed atmospheric and surface temperatures to document the realism of our reference simulation.