We employ the MarsWRF general circulation model (GCM) to test the predictions of a new physical hypothesis: a weak coupling of the orbital and rotational angular momenta of extended bodies is predicted to give rise to cycles of intensification and relaxation of circulatory flows within atmospheres. The dynamical core of the GCM has been modified to include the orbit-spin coupling accelerations due to solar system dynamics for the years 1920-2030. The modified GCM is first subjected to extensive testing and validation. We compare forced and unforced model outcomes for large-scale zonal and meridional flows, and for near-surface wind velocities and surface wind stresses. The predicted cycles of circulatory intensification and relaxation within the modified GCM are observed. Most remarkably, the modified GCM reproduces conditions favorable for the occurrence of perihelion-season global-scale dust storms on Mars in years in which such storms were observed. A strengthening of the meridional overturning (Hadley) circulation during the dust storm season occurs in the GCM in all previously known years with perihelion-season global-scale dust storms. The increased upwelling produced in the southern hemisphere in southern summer may facilitate the transport of dust to high altitudes in the Mars atmosphere during the dust storm season, where radiative heating may further strengthen the circulation. Significantly increased surface winds and surface wind stresses are also obtained. These may locally facilitate saltation and dust lifting from the surface. The numerical simulations constitute proof of concept for the orbit-spin coupling hypothesis under evaluation.
We report the ubiquitous occurrence of nighttime temperature inversions in the tropical martian atmosphere during the dusty season, as observed by the Mars Climate Sounder. The inversions are linked to the occurrence of large-scale regional dust storms, with their strengths largely correlated to the strengths of the dust storms. Inversions strengthen between 2 am and 4 am, with the bases of the inversions getting cooler, and the tops of the inversions getting warmer. The inversions are strongest around Tharsis and Terra Sabaea, which are higher-elevation regions, suggesting they are forming du…
Coagulation of particles occurs when two particles collide and stick together. In the Martian atmosphere, dust coagulation would increase the effective particle size, as small particles accrete to larger particles. Murphy et al. (1990) showed that Brownian coagulation of dust in the Martian atmosphere was not significant, due to the low dust particle mixing ratios, while Montmessin et al. (2002) and Fedorova et al. (2014) showed that it mostly involves particle radii smaller than 0.1 um. However, the effects of coagulation have never been explored in 3D, during a global dust storm, i.e. in pre…
Simulations with the Max Planck Institute Martian general circulation model for Martian years 28 and 34 reveal details of the water "pump" mechanism and the role of gravity wave (GW) forcing. Water is advected to the upper atmosphere mainly by upward branches of the meridional circulation: in low latitudes during equinoxes and over the south pole during solstices. Molecular diffusion plays little role in water transport in the middle atmosphere and across the mesopause. GWs modulate the circulation and temperature during global dust storms, thus changing the timing and intensity of the transpo…
This white paper recognizes gaps in observations that will, when addressed, much improve solar radiation hazard and geomagnetic storm forecasting. Radiation forecasting depends on observations of the entire "Solar Radiation Hemisphere" that we will define. Mars exploration needs strategic placement of radiation-relevant observations. We also suggest an orbital solution that will improve geomagnetic storm forecasting through improved in situ and solar/heliospheric remote sensing.
Martian planet-encircling dust storms or global dust storms (GDS), resulting from the combined influence of local and regional storms, are uncommon aperiodic phenomena: with an average frequency of approximately one every 3-4 MY, they produce a substantial rise in the atmospheric dust loading that lasts from weeks to months and have a significant impact on the atmospheric properties, energy budget, and global circulation. During the 2018/MY34 global dust storm, initiated at L_S = 185$^\circ$ (30-31 May 2018), an intensive atmospheric science campaign was carried out by the Mars Science Laborat…
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 syst…
We study the 2018 Martian Global DustStorm (GDS 2018) over the Southern Polar Region using images obtained by the Visual Monitoring Camera (VMC) on board Mars Express during June and July 2018. Dust penetrated into the polar cap region but never covered the cap completely, and its spatial distribution was nonhomogeneous and rapidly changing. However, we detected long but narrow aerosol curved arcs with a length of 2,000-3,000 km traversing part of the cap and crossing the terminator into the night side. Tracking discrete dust clouds allowed measurements of their motions that were towards the t…
Impact of gravity waves on the middle atmosphere of Mars: a non-orographic gravity wave parameterization based on Global Climate modeling and MCS observations
This thesis work aims to study the possibility of energy production on Martian soil and, in particular, to establish what might be an optimal configuration for an energy system. This goal has been contextualized in the will to feed a scientific base, based the concept of "Mars Direct" (Robert Zubrin, 1990). This habitat has been recreated in its thermal features, in order to perform an analysis of the heat loss over a Martian year (1,88 terrestrial years). As part of this analysis, two possible scenarios have been studied: clear sky with medium solar radiation ("sun season") and sand storm sea…
We present a new implementation of the hydrological cycle scheme into a general circulation model of the Martian atmosphere. The model includes a semi-Lagrangian transport scheme for water vapor and ice, and accounts for microphysics of phase transitions between them. The hydrological scheme includes processes of saturation, nucleation, particle growth, sublimation and sedimentation under the assumption of a variable size distribution. The scheme has been implemented into the Max Planck Institute Martian general circulation model (MPI--MGCM) and tested assuming mono- and bimodal log-normal dis…
Impacting the dayside Martian ionosphere from above and below: Effects of the impact of CIRs and ICMEs close to aphelion (April 2021) and during dust storms (June-July 2022) seen with MAVEN ROSE
Numerous laboratory experiments, starting in the Viking Lander era, have reported that frictional interactions between Martian analog dust grains can catalyze electrostatic processes (i.e. triboelectrification). Such findings have been cited to suggest that Martian dust devils and dust storms may sustain lightning storms, glow discharges, and other complex electrostatic phenomena. However, in many cases (if not most), these experiments allowed Martian dust simulant grains to contact foreign surfaces (for instance, the wall of an environmental chamber or other chemically dissimilar particles). …
Lower atmospheric global dust storms affect the small- and large-scale weather and variability of the whole Martian atmosphere. Analysis of the CO$_2$ density data from the Neutral Gas and Ion Mass Spectrometer instrument (NGIMS) on board NASA's Mars Atmosphere Volatile EvolutioN (MAVEN) spacecraft show a remarkable increase of GW-induced density fluctuations in the thermosphere during the 2018 major dust storm with distinct latitude and local time variability. The mean thermospheric GW activity increases by a factor of two during the storm event. The magnitude of relative density perturbation…
The orbital motions and spin-axis rotations of extended bodies are traditionally considered to be coupled only by tidal mechanisms. The orbit-spin coupling hypothesis supplies an additional mechanism. A reversing torque on rotating extended bodies is identified. The torque effects an exchange of angular momentum between the reservoirs of the orbital and rotational motions. The axis of the torque is constrained to lie within the equatorial plane of the subject body. Hypothesis testing to date has focused on the response to the putative torque of the Martian atmosphere. Atmospheric global circul…
Airborne dust is an important constituent in the Martian atmosphere because of its radiative interaction with the atmospheric circulation, and dust size is one crucial factor in determining this effect. In numerical modeling of the dust processes, description of the dust size is usually dependent on the choice of a particular size distribution function, or with fixed values of effective radius (ER) and effective variance (EV) though they are variable in reality. In this work, analytical expressions have been derived to specify ER and EV for N-bin dust schemes based on the model calculated dust…
High-Latitude Zonal Jets in the Martian Upper Atmosphere Driven by Non-Orographic Gravity Waves
Sorbonne Université（索邦大学）；École Polytechnique（巴黎综合理工学院）；Institut Polytechnique de Paris（巴黎理工学院）；CNRS（法国国家科学研究中心）；Instituto de Astrofisica de Andalucia（安达卢西亚天体物理研究所）；LATMOS/IPSL（大气、空间和环境研究实验室/地球物理与行星系统研究所）；Université d’Orléans（奥尔良大学）
We present results from the Met Office Unified Model (UM), a world-leading climate and weather model, adapted to simulate a dry Martian climate. We detail the adaptation of the basic parameterisations and analyse results from two simulations, one with radiatively active mineral dust and one with radiatively inactive dust. These simulations demonstrate how the radiative effects of dust act to accelerate the winds and create a mid-altitude isothermal layer during the dusty season. We validate our model through comparison with an established Mars model, the Laboratoire de Météorologie Dynamique p…
Global and mesoscale models represent the background (slowly varying) winds on Mars, but short timescale wind variability is not explicitly represented. The local wind erosion and dust deposition model can be useful for more accurate local wind friction, wind friction threshold, horizontal sand flux and vertical dust flux modeling on Mars. Such a model based on the model of Zender \cite{Zender} is proposed in this article. It includes different methods of threshold wind friction estimation and takes into account the influence of atmospheric electric fields on sand and dust elevation processes.…
Jupiter's atmosphere features a variety of clouds that are formed from the interplay of chemistry and atmospheric dynamics, from the deep red color of the Great Red Spot to the high altitude white ammonia clouds present in the zones (bright bands in Jupiter's atmosphere). Beneath these upper level clouds, water condensation occurs, and sporadically leads to the formation of towering convective storms, driven by the release of large amounts of latent heat. These storms result in a widespread disruption of the cloud and dynamical structure of the atmosphere at the latitude where they form, makin…
Comparative terrestrial atmospheric circulation regimes in simplified global circulation models: I. from cyclostrophic super-rotation to geostrophic turbulence
The ExoMars Trace Gas Orbiter (TGO) was sent to Mars in March 2016 to search for trace gases diagnostic of active geological or biogenic processes. We report the first observation of the spectral features of Martian ozone (O3) in the mid-infrared range using the Atmospheric Chemistry Suite (ACS) Mid-InfaRed (MIR) channel, a cross-dispersion spectrometer operating in solar occultation mode with the finest spectral resolution of any remote sensing mission to Mars. Observations of ozone were made at high northern latitudes (>65N) prior to the onset of the 2018 global dust storm (Ls = 163-193). Du…
We analyze Mars Climate Sounder temperature and aerosol data in the tropics to study atmospheric tides and their relation to the dust and water ice distributions. Our results from data covering Mars years (MY) 29-35 reveal that MY29 has large amplitude non-migrating thermal tides during southern hemisphere spring equinox that are not observed at the same local time in any other year. It is the nighttime temperatures that are most perturbed compared to other years, with strong temperature inversions at 35-55 km altitude. Analysis of data at different local times reveals that the temperatures an…
