Using Gravity Wave Resolving Simulations from the NASA Ames Mars Global Climate Model to Inform Parameterized Gravity Wave Drag Schemes

Abstract:

We use gravity wave resolving simulations of the Martian atmosphere using the NASA Ames Mars Global Climate Model (GCM) running at high (0.125°-0.5°) resolution with ~ 100 vertical layers. The simulations allow us to explicitly resolve the greater parts of the orographic and non-orographic gravity wave spectra on a global scale, and offer the opportunity to decipher some cases of convectively-generated gravity waves due to mesoscale circulations and localized dust events. We use Fourier and space-time analyses on the simulated atmospheric fields from the GCM to perform a statistical survey of the waves’ characteristics such as their vertical and horizontal wavelengths, phase speeds, and we compute the momentum fluxes as a function of the geographic location and altitude. The wave characteristics extracted from the high-resolution simulations are used to inform parameterizations for subgrid-scale gravity wave drag based on [Alexander and Dunkerton (1999), J. Atmos. Sci. 56] (a non-orographic scheme) and [Palmer et al. (1986), Meteorol. Soc., 112] (an orographic scheme) when running at low (few degree) horizontal resolution. The objective is to assess if the wave-mean flow forcings and their associated dynamical effects are consistent between the subgrid-scale parameterizations and the explicitly resolved gravity wave drag.