A Surface to Exosphere Non-Orographic Gravity Wave Parameterization for the Mars Planetary Climate Model

摘要

In In this paper, the non-orographic gravity waves (GW) parameterization of the Mars Planetary Climate Model (PCM) previously implemented by Gilli et al. (2020, https://doi.org/10.1029/2018JE005873) is revisited and extended to the exobase (similar to 250 km). The simulations performed with the new scheme correct some known biases in the modeled thermal tide amplitudes and polar warming, improving the agreement with Mars Climate Sounder (MCS) observed thermal structures and tides below similar to 100 km. Additionally, we find that the simulated densities above 150 km are compatible with NGIMS (Neutral Gas and Ion Mass Spectrometer) measured abundances. Large drag depositions ranging up to >similar to 950 m s(-1) sol(-1) are induced at altitude of 90-170 km due to the wave saturation (breaking) and depletion, leading to winds damped to magnitudes of similar to 150-225 and similar to 80 m s(-1) in the zonal and meridional directions, respectively. Resulting temperature variations are similar to +/- 10-30 K or 5-10 at most latitudes except in the polar regions (where they can reach similar to +/- 30-60 K). The results indicate that non-orographic GW play a significant role in the dynamics of the middle-upper atmosphere of Mars via the induced transfer of momentum and energy from the lower atmosphere. Plain Language Summary Atmospheric gravity (buoyancy) waves are oscillations that result from flows over topography (orographic gravity waves (GW)) or perturbations caused by convective forcing, front systems, and jet streams (non-orographic GW). In this paper, we model non-orographic GW as a Gaussian wave packet, which is the sum of several monochromatic waves of random wavenumbers and frequencies. The wave packets are launched vertically from low altitudes (similar to 6 km), where the mean Mars Planetary Boundary Layer is located. We reproduce several features of the thermal structure and tides observed by the MCS by implementing our scheme to the Mars PCM. The scheme has a strong effect on the model's wind fields above an altitude of 35-40 km, transporting momentum from the source layers to higher layers, and even up to the thermosphere (altitude >similar to 100 km). The temperature and density variations generated by the scheme are comparable to the observations made by the Neutral Gas and Ion Mass Spectrometer. Our results demonstrate that non-orographic GW play a crucial role in the momentum-energy transport that affects the dynamics of the middle and upper atmosphere of Mars.