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Atmospheric oscillations with daily periodicity are observed in in situ near-surface pressure, temperature, and winds observations and also in remotely sensed temperature and pressure observations of the Martian atmosphere. Such oscillations are interpreted as thermal tides driven by the diurnal cycle of solar radiation and occur at various frequencies, with the most prominent being the diurnal, semidiurnal, terdiurnal, and quadiurnal tides. Mars global circulation models reproduce these tides with varying levels of success. Until recently, both the MarsWRF and newly developed MarsMPAS models were able to produce realistic diurnal and semidiurnal tide amplitudes but predicted higher-order mode amplitudes that were significantly weaker than observed. We use linear wave analysis to show that the divergence damping applied within both MarsWRF and MarsMPAS is responsible for suppressing the amplitude of thermal tides with frequency greater than 2 per sol, despite being designed to suppress only acoustic wave modes. Decreasing the strength of the divergence damping in MarsWRF and MarsMPAS allows for excellent prediction of the higher-order tidal modes. This finding demonstrates that care must be taken when applying numerical dampers and filters that may eliminate some desired dynamical features in planetary atmospheres.

We present a new planetary global circulation model, planetMPAS, based on the state-of-the-art NCAR MPAS General Circulation Model. Taking advantage of the cross compatibility between WRF and MPAS, planetMPAS includes most of the planetWRF physics parameterization schemes for terrestrial planets such as Mars and Titan. PlanetMPAS also includes a set of physics that represents radiative transfer, dry convection, moist convection and its associated microphysics for the Jovian atmosphere. We demonstrate that, despite the rigid-lid approximation, planetMPAS is suitable to simulate the climate systems in Martian and Jovian atmospheres with potential application to slow-rotating planets such as Titan. Simulations using planetMPAS show that the new model can reproduce many aspects of the observed features on Mars and Jupiter, such as the seasonal CO2 cycle, polar argon enrichment, zonal mean temperature, and qualitative dust opacity on Mars, as well as the equatorial superrotation and banded zonal wind patterns on Jupiter., Manuscript has 61 pages, 20 figures, 2 tables, submitted to Planetary and Space Science

Early Mars had rivers, but the cause of Mars’s wet-to-dry transition remains unknown. Past climate on Mars can be probed using the spatial distribution of climate-sensitive landforms. We analyzed global databases of water-worked landforms and identified changes in the spatial distribution of rivers over time. These changes are simply explained by comparison to a simplified meltwater model driven by an ensemble of global climate model simulations, as the result of ≳10 K global cooling, from global average surface temperature T ¯ ≥ 268 K to T ¯ ~ 258 K, due to a weaker greenhouse effect. In other words, river-forming climates on early Mars were warm and wet first, and cold and wet later. Unexpectedly, analysis of the greenhouse effect within our ensemble of global climate model simulations suggests that this shift was primarily driven by waning non-CO 2 radiative forcing, and not changes in CO 2 radiative forcing.

This article has a correction. Please see: Erratum for the Research Article: “The dynamic atmospheric and aeolian environment of Jezero crater, Mars” - 10 February 2023 Despite the importance of sand and dust to Mars geomorphology, weather, and exploration, the processes that move sand and that raise dust to maintain Mars’ ubiquitous dust haze and to produce dust storms have not been well quantified in situ, with missions lacking either the necessary sensors or a sufficiently active aeolian environment. Perseverance rover’s novel environmental sensors and Jezero crater’s dusty environment remedy this. In Perseverance’s first 216 sols, four convective vortices raised dust locally, while, on average, four passed the rover daily, over 25% of which were significantly dusty (“dust devils”). More rarely, dust lifting by nonvortex wind gusts was produced by daytime convection cells advected over the crater by strong regional daytime upslope winds, which also control aeolian surface features. One such event covered 10 times more area than the largest dust devil, suggesting that dust devils and wind gusts could raise equal amounts of dust under nonstorm conditions. We gratefully acknowledge the huge effort by the entire Mars 2020 team to meet our launch date despite the COVID-19 pandemic, to land and deploy instruments successfully in Jezero crater, and to conduct operations on the surface of Mars since February 2021. This paper arose from discussions within the Mars 2020 Atmospheres Working Group but would not have been possible without the tremendous contributions of everyone involved in Mars 2020 operations. We wish to especially pay tribute to the many team members based in Europe who regularly work through the night as MEDA or SuperCam Payload Uplink and Downlink Leads (PULs/PDLs) or in other roles and to all those who had shifts as Atmospheres Working Group representatives during this period. Last, we gratefully acknowledge the very helpful and constructive comments from both anonymous reviewers. Funding: R.H., A.S.-L., A.M., and T.d.R.-G. are supported by Spanish Ministry of Science and Innovation project PID2019-109467GB-I00 funded by MCIN/AEI/10.13039/501100011033/ and Grupos Gobierno Vasco IT1366-19. I.A., D.T., and V.A. are supported by the Spanish National Research, Development, and Innovation Program through the grants RTI2018-099825-B-C31, ESP2016-80320-C2-1-R, and ESP2014-54256-C4-3-R. L.M., S.N., and J.G.-E. are supported by the Spanish Ministry of Economy and Competitiveness, projects ESP2014-54256-C4-1-R and AYA2015-65041-P; the Spanish Ministry of Science, Innovation, and Universities, projects ESP2016-79612-C3-1-R, ESP2016-80320-C2-1-R, RTI2018-098728-B-C31, and RTI2018-099825-B-C31; and the Spanish Ministry of Science and Innovation’s Centre for the Development of Industrial Technology, projects RTI2018-098728-B-C31 and RTI2018-099825-B-C31. Á.V.-R. and M.-P.Z. are supported by Spanish State Research Agency (AEI) project no. MDM-2017-0737 Unidad de Excelencia “María de Maeztu”–Centro de Astrobiología (INTA-CSIC). M.-P.Z. is supported by the Spanish Ministry of Science and Innovation, PID2019-104205GB-C21. M.M.B. and M.-P.Z. are supported by NASA’s Mars 2020 Participating Scientist Program. All other authors were supported by funding from the Mars 2020 mission, part of the NASA Mars Exploration Program. Work by C.E.N. was additionally funded by the InSight Participating Scientist Program.A portion of this work was performed at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with NASA and funding by SMD, GCD, and STMD. Peerreview

Analysis of dust and water ice variation is carried out using observations from the Mars Climate Sounder (MCS), which includes the data for six years (during Martian years 29–34). This study only used the nighttime observations, as these profiles extend closer to the surface compared to the daytime. The correlation between dust opacity and water ice opacity is found to switch sign between the low-dust northern spring and summer (LS ​= ​0°–180°) and high-dust southern spring and summer seasons (LS ​= ​180°–360°). Density-scaled opacity profiles show the correlation between dust and water ice variability over the southern hemisphere and the tropics, which alters between 20 and 40 ​km altitudes. The positive correlation during the low-dust period over the latitudes 40–80°S is mainly controlled by the water ice cycle in the south polar hood clouds. Whereas the water ice cycle within the tropical cloud belt (TCB) serves as a primary controlling factor, and the presence of atmospheric dust prevails only in its formation stage within the latitudes -20 – 40°N. During the high-dust period, at southern latitudes, significant dust lifting and the associated temperature change are found to be the reason for the strong negative correlation with ice clouds. And in tropical latitudes, the significant positive relationship at relatively high altitudes (∼40 ​km) is possibly due to the presence of thin or haze clouds. The global dust storm occurrence only modulates the correlation behavior during the high-dust period, and the influence is seen above ∼40 ​km altitude that indicates an enhanced vertical advection sustained till late northern winter. Based on analysis of observational data and simulations with the MarsWRF model, it is found that the difference in correlation behavior between low and high-dust seasons could be explained from the variations in the planetary boundary layer height. Moreover, the dust and water ice interaction pattern has a prominent seasonal variation that is influenced by the water ice cycle, dust cycle, or the dust-ice microphysical relationship. It also has an altitudinal dependency, which changes between low-dust, high-dust, or global dust storm scenarios.