Characterizing Dust‐Radiation Feedback and Refining the Horizontal Resolution of the MarsWRF Model Down to 0.5 Degree

C Gebhardt,M.‐P Zorzano,R M Fonseca,J Martín‐Torres,A Abuelgasim

doi:10.1029/2020je006672

Abstract

AbstractIn this study, three simulations by the Mars Weather Research and Forecasting Model are compared: two 10 Martian year (MY) 2° × 2° simulations with (i) fully radiatively active dust and (ii) a prescribed dust scenario, and a (iii) 1 MY 0.5° × 0.5° simulation with prescribed dust as in (ii). From comparing (i) and (ii), we found that the impact of dust‐radiation feedback is individually different for any region. The most striking evidence are major dust lifting activities to the south of Chryse Planitia (S‐CP) seen in (i) but not in (ii). By contrast, dust lifting and deposition on the southern slopes and inside the Hellas Basin are similar in both simulations. The latter, in turn, points toward a similar near‐surface atmospheric circulation. In (iii), the total global amount of wind stress lifted dust is by a factor of ∼8 higher than in (ii), with S‐CP being a major lifting region as in (i). Nonetheless, the surface dust lifting by wind stress in (iii) may be also reduced regionally, as seen at the peak of Elysium Mons because of its unique topography. The zonal mean circulation in (i) is generally of a comparable strength to that in (ii), with exceptions in global dust storm years, when it is clearly stronger in (i), in line with a dustier atmosphere. The differences in the zonal mean circulation between (ii) and (iii) are mostly at lower altitudes and may arise because of differences in the representation of the topography.

Highlights

This study is based on the intercomparison of three Mars Weather Research and Forecasting (MarsWRF) model simulations: (1) Interactive dust at 2° × 2° horizontal resolution, simulation IC; (2) is as (1) but with a prescribed dust scenario, simulation PC; and (3) is as (2) but with 0.5° × 0.5° horizontal resolution and a smaller integration time step, simulation PH
Several major dust lifting regions were identified therein such as south of Chryse Planitia (S-CP), on the northern and southern slopes of the Hellas Basin (N-HB and S-HB), north of Olympus Mons (N-OM), and east of the peak region of Elysium Mons (E-EM)
The total mass of the surface dust lifted by the wind stress from the first-to-last-sol is compared between simulations IC and PC, both globally and for major dust lifting regions separately

Summary

General Introduction

On Mars, dust is lifted from the surface into the atmosphere by the winds and dust devils and is subsequently transported by atmospheric advection and global circulation over local, regional, and planetary scales. Global and mesoscale circulation models have simulation routines, or so-called parametrization schemes, that describe the physics of dust lifting, transport, and sedimentation, as well as the dust’s interaction with radiation These model schemes have tunable parameters that directly control physical processes such as the amount of dust lifted from the surface into the atmosphere. It is possible to calibrate or “tune” such parameters by comparing model simulations with orbital observations of certain measurable quantities, such as satellite data of the atmospheric temperature and others This approach is followed by a number of studies such as Basu et al (2004), Newman and Richardson (2015), Newman et al (2019), and Gebhardt et al (2020a), just to name some of them. To illustrate and quantify the impact on the dust cycle arising from dust-radiation feedback and varying spatial resolution, we perform here a comparison study of three model simulations: two with 2° × 2° and one with 0.5° × 0.5° horizontal resolution

The Dust Cycle and Dust-Radiation Feedback

Concept and Structure of This Article

The Dust Cycle in Mars General Circulation Models

Summary and Conclusion

Findings

Data Availability Statement