Session PS1.8

[Programme]

PS1.8 | Atmospheres, exospheres, and surfaces of terrestrial planets, satellites, small bodies, and exoplanets

Atmospheres, exospheres, and surfaces of terrestrial planets, satellites, small bodies, and exoplanets

Convener: Arnaud Beth | Co-conveners: Arianna Piccialli, Shane Carberry MoganECSECS, Quentin Nénon

Orals

| Tue, 16 Apr, 10:45–12:30 (CEST)

Room L1

Posters on site

| Attendance Wed, 17 Apr, 10:45–12:30 (CEST) | Display Wed, 17 Apr, 08:30–12:30

Hall X3

Posters virtual

| Attendance Wed, 17 Apr, 14:00–15:45 (CEST) | Display Wed, 17 Apr, 08:30–18:00

vHall X3

This session primarily focuses on neutral atmospheres, surfaces, and exospheres of terrestrial bodies other than the Earth. This includes not only Venus and Mars, but also exoplanets with comparable envelopes, small bodies and satellites carrying dense atmospheres such as Titan, exospheres such as Ganymede, or with a surface directly exposed to space like asteroids. We welcome contributions dealing with processes affecting the atmospheres of these bodies, from the surface to the exosphere. We invite abstracts concerning observations, both from Earth or from space, modeling and theoretical studies, or laboratory work. Comparative planetology abstracts will be particularly appreciated.

Orals: Tue, 16 Apr | Room L1

Chairpersons: Arnaud Beth, Arianna Piccialli

10:45–10:50

5-minute convener introduction

Venus

10:50–11:00

EGU24-5297

On-site presentation

Consequences of Impact Erosion and Volatile Loss Processes on the Evolution of Venus.

Cédric Gillmann and Gregor Golabek

We model the long-term evolution of Venus through volatile exchanges and compare observed and simulated present-day states. This work focuses on quantifying the effect of different parameterizations for loss processes on the overall evolution.

Due to both the striking similarities and the obvious differences between Earth and Venus, understanding Venus might hold keys to how planets become -and cease to be- habitable. It has been suggested that the divergence between Earth and Venus could occur during the first few hundred million years due to interaction between the interior of the planet, its atmosphere and escape mechanisms.

We develop coupled numerical simulations of the atmosphere and interior to test what evolutionary paths can reproduce the observed present-day state of Venus. They include modeling of mantle dynamics, core evolution, volcanism/outgassing, surface alteration, atmospheric escape (hydrodynamic and non-thermal), volatile deposition and loss through impacts. Impact histories representing different possible scenarios for late accretion are generated using n-bodies simulations.

Our previous efforts used hydrocode results to model impact erosion. A new parameterization has since been proposed by Kegerreis et al. (2020), with increased losses for high-energy collisions. We test if these results induce divergences between different impact histories (e.g., giant impact vs. small impactors) and combine these different parameterizations depending on impactor size.

Post-hydrodynamic escape, non-thermal loss mechanisms can remove low amounts of water and oxygen, from the surface/atmosphere (4 mbar to a few bar), making it quite difficult to accommodate large bodies of water, especially during Venus’ recent past. Trapping oxygen on the surface through oxidation of newly emplaced volcanic material through solid-gas reactions appears inefficient (totalling loses similar to non-thermal escape). Runaway greenhouse resulting in a molten surface could lead to the loss of multiple bars of oxygen but still leaves behind a significant atmospheric inventory. These results imply a maximum limit to water delivery by impacts.

Atmospheric delivery and erosion by impacts seem to be the largest source/sink of volatile species during evolution. The choice of parameterization for erosion can induce a large difference in total inventory (up to several 1-10 bar of H₂O and CO₂). However maximum delivery by impactors over Late Accretion are still limited by loss processes. Previously obtained upper limits for water content of the Late Accretion (95-98% dry enstatite chondrite, 2-5% of carbon chondrite) are revised upward to 5-10% Carbon chondrites for efficient atmospheric erosion models.

How to cite: Gillmann, C. and Golabek, G.: Consequences of Impact Erosion and Volatile Loss Processes on the Evolution of Venus., EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-5297, https://doi.org/10.5194/egusphere-egu24-5297, 2024.

11:00–11:10

EGU24-8133

On-site presentation

Ephemeral Ice Clouds in the Upper Atmosphere of Venus

John Plane, Benjamin Murray, Thomas Mangan, and Anni Määttänen

Venus is well known for extreme heat at its surface and being shrouded in clouds composed of sulphuric acid. However, there are regions of Venus’ atmosphere around 120 km that are cold enough to harbour ice clouds, under conditions similar to the upper mesospheres of Earth and Mars where ice clouds form. In this presentation we will show, using published satellite products and numerical modelling, that the upper mesosphere of Venus can be cold enough for both H₂O and CO₂ to condense and form particles. Amorphous solid water particles (ASW) are likely to nucleate both heterogeneously on meteoric smoke (formed from the condensation of the metallic vapours which ablate from cosmic dust particles entering Venus’ atmosphere) and also homogeneously, resulting in clouds of nano-scaled particles at around 120 km that will occur globally. The temperatures may become cold enough (below ~90 K) that CO₂ particles nucleate on ASW particles. Taking account of the uncertainty associated with retrievals of temperature in the upper mesosphere (using the SOIR instrument on Venus Express), CO₂ ice cloud formation could occur more than 30% of the time poleward of 60^o. Since the main component of Venus’ tenuous atmosphere is CO₂, any CO₂ crystals that form will grow and sediment on a timescale of a few minutes. Mie calculations show that these Venusian mesospheric clouds (VMCs) should be observable by contemporary satellite instruments, although their short lifetime means that the probability of detection is small. We suggest that VMCs are important for the redistribution of meteoric smoke and may serve as a cold-trap, removing some water vapour from the very upper mesosphere of Venus through the growth and sedimentation of cloud particles, and possibly reducing the loss of water to space.

How to cite: Plane, J., Murray, B., Mangan, T., and Määttänen, A.: Ephemeral Ice Clouds in the Upper Atmosphere of Venus, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-8133, https://doi.org/10.5194/egusphere-egu24-8133, 2024.

11:10–11:20

EGU24-793

ECS

On-site presentation

Exploring the Venusian clouds: Atmospheric Gravity Waves with Akatsuki UVI instrument

Daniela Espadinha, Pedro Machado, Javier Peralta, José Silva, and Francisco Brasil

Atmospheric gravity waves are oscilatory disturbances that occur on a specific layer of the atmosphere and whose restoration force is buoyancy [2]. Because of this, these waves can only exist in a continuously stably stratified atmosphere. These waves play an essential role in the global circulation of a planets atmosphere. They are responsible for very important dynamic phenomena such as, for example, the vertical transfer of energy, momentum and chemical species (atmospheric gravity waves transport energy and momentum from the troposphere and deposit it in the thermosphere and mesosphere) since they can form on one region of the atmosphere and travel through it, sometimes over great distances [1]. As such, the study of the properties of atmospheric gravity waves is an essential tool to answer some of the fundamental questions regarding the Venusian atmosphere dynamics, in particular, the fascinating mechanism of superrotation of the atmosphere.

With this work we present observations of wave-like structures on the dayside of Venuss atmosphere using the ultraviolet wavelength of 365nm from Akatsuki’s UVI instrument. The main goal is to evaluate the population of atmospheric waves in Akatsuki’s public database by measuring their physical properties(crest number, horizontal wavelength, packet length, width and orientation ), dynamical properties and distribution in order to establish possible links with previous studies of waves. This work follows a previous study performed by Peralta et al. (2008)[1] and by Silva et al. (2021) [3].

[1] Peralta et al., Characterization of mesoscale gravity waves in the upper and lower clouds of venus from vex-virtis images. Journal of Geophysical Research: Planets, 113(E5), 2008.
[2] Piccialli et al., High latitude gravity waves at the venus cloud tops as observed by the venus monitoring camera on board venus express. Icarus, 227:94 111, 01 2014.
[3] Silva et al., Characterising atmospheric gravity waves on the nightside lower clouds of Venus: a systematic analysis, AA 649 A34, 2021.

How to cite: Espadinha, D., Machado, P., Peralta, J., Silva, J., and Brasil, F.: Exploring the Venusian clouds: Atmospheric Gravity Waves with Akatsuki UVI instrument, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-793, https://doi.org/10.5194/egusphere-egu24-793, 2024.

Mars

11:20–11:30

EGU24-2981

ECS

On-site presentation

Diurnal Temperature Variations and Thermal Tides in the Martian Atmosphere before and during Regional Dust Storms Observed by EMIRS

Siteng Fan, François Forget, Michael Smith, Sandrine Guerlet, Khalid Badri, Samuel Atwood, Roland Young, Christopher Edwards, Philip Christensen, Justin Deighan, Hessa Almatroushi, Antoine Bierjon, Jiandong Liu, and Ehouarn Millour

The Martian atmosphere experiences large diurnal variations due to its small thickness and low heat capacity. Driven by diurnal solar insolation and influenced by topography and radiative drivers (clouds and dust), diurnal temperature changes propagate from lower atmosphere into higher altitudes as forms of atmospheric tides. However, our understanding of diurnal variations in the Martian atmosphere is poor due to the lack of observations, especially those covering the entire planet and all local times, until recent. In its novelly designed high-altitude orbit, instruments onboard the Hope probe of the Emirates Mars Mission (EMM) could obtain a full geographic and local time coverage of Mars every 10 Martian days (Almatroushi et al., 2021). The Emirates Mars InfraRed Spectrometer (EMIRS, Edwards et al., 2021) observes surface temperature, temperature profile, dust content, water clouds, and water vapor in the lower atmosphere. Diurnal variations of such properties are derived on a planetary scale for the first time without significant gaps in local time or interference from seasonal changes. Such a rapid full planetary-scale coverage is ideal for investigating the fast-changing dust storms on Mars. In this talk, we present results of diurnal temperature variations and thermal tides before, during, and after several regional dust storms in Martian Year (MY) 36 and 37, and their coupling with dust and clouds. The results are also compared with numerical simulations by the Mars Planetary Climate Model (PCM), providing valuable information on physical processes controlling the diurnal climate of Mars.

Almatroushi, H., AlMazmi, H., AlMheiri, N., AlShamsi, M., AlTunaiji, E., Badri, K., et al. (2021). Emirates Mars Mission Characterization of Mars Atmosphere Dynamics and Processes. Space Science Reviews, 217(8), 89. https://doi.org/10.1007/s11214-021-00851-6

Edwards, C. S., Christensen, P. R., Mehall, G. L., Anwar, S., Tunaiji, E. A., Badri, K., et al. (2021). The Emirates Mars Mission (EMM) Emirates Mars InfraRed Spectrometer (EMIRS) Instrument. Space Science Reviews, 217(7), 77. https://doi.org/10.1007/s11214-021-00848-1

How to cite: Fan, S., Forget, F., Smith, M., Guerlet, S., Badri, K., Atwood, S., Young, R., Edwards, C., Christensen, P., Deighan, J., Almatroushi, H., Bierjon, A., Liu, J., and Millour, E.: Diurnal Temperature Variations and Thermal Tides in the Martian Atmosphere before and during Regional Dust Storms Observed by EMIRS, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-2981, https://doi.org/10.5194/egusphere-egu24-2981, 2024.

11:30–11:40

EGU24-12803

ECS

On-site presentation

Photochemistry of the Recent Martian Atmosphere at Different Obliquities

Yangcheng Luo, Franck Lefèvre, and François Forget

Due to gravitational perturbations from nearby planets, Mars has undergone large obliquity variations through its history. Modeling suggested that in the past 10 million years, the obliquity of Mars has varied by up to 20°, from 15° to 35°. During time periods of high obliquity, the polar regions of Mars received more solar insolation and became warmer, leading to more rapid sublimation of water ice and higher atmospheric water content. During periods of low obliquity, on the contrary, water vapor condensed in polar regions and the atmosphere became dry. This variation has a significant impact on the photochemistry of the Martian atmosphere, as HO_x radicals, which are photolytic products of water vapor, are key catalysts to the photochemistry of the Martian atmosphere. It is then of interest to explore the photochemistry of Mars at different obliquities and its effects on the climate and surface of Mars, as part of the objectives of the “Mars Through Time” European Research Council project. In preparation for future Mars sample return missions, it is important to evaluate the preservability of potential organic matter buried in the shallow subsurface with different oxidizing capacities of the atmosphere at different obliquities.

In view of the three-dimensional nature of the sublimation, transport, and condensation of water, we employ a fully coupled photochemical-radiative-dynamical model—the Mars Planetary Climate Model, developed at LMD in collaboration with other institutions—to simulate the photochemistry of the recent Martian atmosphere at obliquities between 15° and 35°. We find that at high obliquities, water content of the Martian atmosphere could exceed the present-day value by more than one order of magnitude, and the OH concentration could be higher by up to two orders of magnitude. These drastic changes result in a significantly lower CO concentration. Opposite effects are observed from low-obliquity simulations. The nonlinearity in the photochemical system, however, has led to more complex behaviors of the HO₂ and H₂O₂ concentrations. We will explain the mechanisms behind these effects and discuss their implications in the paleoclimate of Mars and the preservation of potential biogenic organic matter in the shallow subsurface. We will also address the long-standing “CO-deficit” problem in Mars photochemical modeling, and show how the state-of-the-art 3D photochemical modeling helps to mitigate the problem.

How to cite: Luo, Y., Lefèvre, F., and Forget, F.: Photochemistry of the Recent Martian Atmosphere at Different Obliquities, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-12803, https://doi.org/10.5194/egusphere-egu24-12803, 2024.

11:40–11:50

EGU24-15988

ECS

On-site presentation

The Martian Recurring Slope Lineae: Granular Flows Linked with Wind and Dust

Yann Leseigneur, Mathieu Vincendon, and Qing Zhang

Recurring Slope Lineae (hereinafter RSL) are seasonal dark flows observed on steep slopes (≳ 25°) of Mars that are overall dark (slope albedo < 0.2) (McEwen et al., 2011). These movements of up to a few hundred meters long appear and grow downwards (more or less incrementally), fade (partially or totally) more or less progressively, and recur almost every year. After considering it as liquid water or brine flows, the RSLs are now widely considered as granular flows of dark sand or dust, both involving dust at different levels. Mechanisms that may drive these movements are however not precisely understood. One of the main common features between RSL and dust is seasonality: major RSL formations are for example observed during the dust storm season, and RSL formation is enhanced after global dust storms. Here, we aim to better understand the role of dust and winds in these movements.

We have first concentrated our study on Hale crater (323.48°E, 35.68°S), a well-studied RSL site located within an area of higher dust storm detections in the OMEGA/Mars Express dataset. Images taken by the HiRISE camera onboard Mars Reconnaissance Orbiter (during Martian Years 31, 32 and 33) have been used to characterise the RSL annual activities. We defined 3 intensity levels to classify formations and disappearances. Then, we compared these RSL activities to atmospheric dust optical depth measurements and Mars Climate Database (MCD) predictions of dust deposition and winds. Finally, we computed the effective reflectance values of several consecutive HiRISE images, taking into account the local slope of the surface, to quantify darkening and brightening.

We observed that RSL formation and disappearance are correlated with the atmospheric dust optical depth variations. We also noticed that the prediction of dust deposition rate reaches two maxima during the dust storm season that occur simultaneously with intermediate and high RSL disappearance levels. Reflectance variations showed that RSL can disappear both by brightening and darkening, with relative variations from a few per cent to 40%, suggesting that RSL can also disappear by widespread dust removal all over the RSL slope. We also identified some correlations between RSL activities and wind predictions: the maximum of surface wind stress is reached during the first period (of the year) of high RSL formation level, and the convective winds reach high values during the dust storm season (L_s ~ 180-360°), corresponding to intermediate and high RSL formation levels. Overall, these results suggest that dust deposition/removal and winds are involved in the RSL disappearance and formation mechanisms at Hale crater.

How to cite: Leseigneur, Y., Vincendon, M., and Zhang, Q.: The Martian Recurring Slope Lineae: Granular Flows Linked with Wind and Dust , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-15988, https://doi.org/10.5194/egusphere-egu24-15988, 2024.

Titan

11:50–12:00

EGU24-691

ECS

On-site presentation

A study of very high resolution visible spectra of Titan: Line characterisation in visible CH4 bands and the search for C3

Rafael Rianço-Silva, Pedro Machado, Zita Martins, Emmanuel Lellouch, Jean-Christophe Loison, Michel Dobrijevic, João Dias, and José Ribeiro

The atmosphere of Titan is a unique natural laboratory for the study of atmospheric evolution and photochemistry akin to that of the primitive Earth (1), with a wide array of complex molecules discovered through infrared and sub-mm spectroscopy (2) (3). Here, we present the results of the exploration of original, ground-based, very high-resolution visible spectra of Titan, obtained with VLT-UVES (4). We have developed a new, Doppler-based line detection method which allowed to retrieve an empirical, high resolution (R = 100.000) line list of methane between 525 nm and 618 nm, for which no similar line lists are yet available (5), identifying and characterising more than 90 new high energy CH₄ absorption lines at low temperature (T = 150 K).

Furthermore, we searched for the predicted, but previously undetected carbon trimer molecule, C₃, (6) (7), on the atmosphere of Titan, at its 405.1 nm band, by comparing VLT-UVES Titan spectra with a line-by-line (8) model spectrum of Titan’s atmosphere with C₃. Our results are consistent with the presence of C₃ at the upper atmosphere of Titan, with a column density of 10¹³ cm^-2. This study of Titan's atmosphere with very high-resolution visible spectroscopy presents a unique opportunity to observe a planetary target with a CH₄-rich atmosphere, from which CH₄ optical proprieties can be studied (9). It also showcases the use of a close planetary target to test new methods for chemical retrieval of minor atmospheric compounds, in preparation for upcoming studies of cold terrestrial exoplanet atmospheres (10).

References: (1) Hörst S., 2017; J. Geophys. Res. Planets, doi:10.1002/2016JE005240; (2) Nixon C., et al, 2020; The Astronomical Journal, doi:10.3847/1538-603881/abb679; (3) Lombardo N., et al, 2019, The Astrophysical Journal Letters, 2019, doi:10.3847/2041- 658213/ab3860; (4) Rianço-Silva R., et al, 2023, submitted to Planetary and Space Sciences (under peer-review). (5) Hargreaves R., et al, 2020; The Astrophysical Journal Supplement Series, doi:10.3847/1538-4365/ab7a1a; (6) Hérbad E., et al, 2013; Astronomy & Astrophysics, doi:10.1051/0004-6361/201220686; (7) Dobrijevic M., et al, 2016; Icarus, doi.org/10.1016/- j.icarus.2015.12.045; (8) Schmidt M., et al, 2014; MNRAS, doi.org/10.1093/mnras/stu641; (9) Thompson M., et al, 2022; PNAS, doi.org/10.1073/pnas.2117933119; (10) Tinetti G., et al, 2018; Experimental Astronomy, doi:10.1007/s10686-018-9598-x;

How to cite: Rianço-Silva, R., Machado, P., Martins, Z., Lellouch, E., Loison, J.-C., Dobrijevic, M., Dias, J., and Ribeiro, J.: A study of very high resolution visible spectra of Titan: Line characterisation in visible CH4 bands and the search for C3, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-691, https://doi.org/10.5194/egusphere-egu24-691, 2024.

12:00–12:10

EGU24-6486

On-site presentation

The Structure and Evolution of Titan’s Daytime Planetary Boundary Layer

Scot Rafkin, Guillermo Chin Canche, and Alejandro Soto

The structure and evolution of Titan’s daytime planetary boundary layer (PBL) are investigated through large eddy simulation (LES) modeling. The PBL is the interface between the surface and the free atmosphere through which energy, mass, and momentum are exchanged via turbulent eddies. The sounding from the Huygens probe provided the only direct, vertically resolved measurement of the structure of the PBL at a single moment in time. How the observed structures develop and evolve remain uncertain, and the turbulent exchange processes are challenging to constrain from the single profile. LES techniques provide a mechanism for understanding the observed structure and dynamics of the PBL, better constraining turbulent atmosphere-surface exchange, and improving the parameterization of the PBL in larger-scale models. Results from LES studies forced by diurnally-varying radiation are presented for Titan. The development of three distinct PBL layers are noted: 1) a near-surface layer dominated by frictional dissipation; 2) a mixed-layer of near neutral stability; and 3) a relatively deep entrainment layer capping the top of the PBL. The three layers are similar in character to what is often observed in the Earth’s convective PBL. The interpretation of the modeled structures and PBL evolution in the current LES study differs significantly from previous mechanisms inferred from GCM studies and shows important differences from prior work that lacked diurnally-varying radiative forcing.

How to cite: Rafkin, S., Chin Canche, G., and Soto, A.: The Structure and Evolution of Titan’s Daytime Planetary Boundary Layer, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-6486, https://doi.org/10.5194/egusphere-egu24-6486, 2024.

12:10–12:20

EGU24-3

ECS

On-site presentation

A Novel Backtracing Model to Study the Emission of Energetic Neutral Atoms at Titan

Tyler Tippens, Elias Roussos, Sven Simon, and Lucas Liuzzo

To study the emission of energetic neutral atoms (ENAs) at Titan, we have developed a novel model that takes into account a spacecraft detector’s limited field of view and traces energetic magnetospheric particles backward in time. ENAs are generated by charge exchange between Titan’s atmospheric neutrals and energetic magnetospheric ions. By tracing these ions through the draped electromagnetic fields in Titan’s environment, we generate synthetic ENA images and compare them to Cassini observations from the TA flyby. Our model can reproduce the intensity and morphology of the observed images only when field line draping is included. Using a realistic detector geometry is necessary to determine the influence of this draping on the ENA images: the field perturbations eliminate a localized feature in the emission pattern, which is a different effect than found by previous models utilizing an infinitely extended detector. We demonstrate that ENA observations from TA contain signatures of the time-varying Saturnian magnetospheric environment at Titan: the modeled ENA emission morphology and the effect of field line draping are different for the background field vectors measured during the inbound and outbound legs of TA. The visibility and qualitative effect of the draping on observed ENA images vary strongly between different detector locations and pointings. Depending on the viewing geometry, field line draping may add features to the synthetic ENA images, remove features from them, or have no qualitative effect at all. Our study emphasizes the challenges and the potential for remote sensing of Titan’s interaction region using ENA imaging.

How to cite: Tippens, T., Roussos, E., Simon, S., and Liuzzo, L.: A Novel Backtracing Model to Study the Emission of Energetic Neutral Atoms at Titan, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-3, https://doi.org/10.5194/egusphere-egu24-3, 2024.

Terrestrial planets

12:20–12:30

EGU24-16259

ECS

On-site presentation

Clouds and Seasonality on Terrestrial Planets with Varying Rotation Rates

Daniel Williams, Xuan Ji, Paul Corlies, and Juan Lora

Clouds have been observed on Venus, Mars and Titan, and a growing number of exoplanets, yet the connection between planetary rotation rate and cloud distribution has not previously been extensively investigated. Using an idealised climate model incorporating seasonal forcing, we investigate the impact of rotation rate on the abundance of clouds on an Earth-like aquaplanet, and the resulting impacts upon albedo and seasonality. We show that the cloud distribution varies significantly with season, depending strongly on the rotation rate, and is well explained by the large-scale circulation and atmospheric state. Planetary albedo displays non-monotonic behaviour with rotation rate, peaking around one half of Earth’s rotation rate. Clouds reduce the surface temperature and total precipitation relative to simulations without clouds at all rotation rates, and reduce the dependence of precipitation on rotation rate. Clouds also affect the amplitude and timing of seasonality, in particular by modifying the width of the Hadley cell at intermediate rotation rates. The timing of seasonal transitions varies with rotation rate; the addition of clouds further modifies this phase lag, most notably at Earth-like rotation rates. Our results may inform future characterisation of terrestrial exoplanets, in particular informing estimates of planetary rotation for non-synchronous rotators.

How to cite: Williams, D., Ji, X., Corlies, P., and Lora, J.: Clouds and Seasonality on Terrestrial Planets with Varying Rotation Rates , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-16259, https://doi.org/10.5194/egusphere-egu24-16259, 2024.

Posters on site: Wed, 17 Apr, 10:45–12:30 | Hall X3

Display time: Wed, 17 Apr 08:30–Wed, 17 Apr 12:30

Chairperson: Arnaud Beth

Moon

X3.54

EGU24-18377

ECS

OSPP

A comprehensive study on the sputtering of the lunar surface

Johannes Brötzner, Herbert Biber, Noah Jäggi, Andreas Nenning, Lea Fuchs, Paul Stefan Szabo, André Galli, Peter Wurz, and Friedrich Aumayr

The Moon is subjected to a variety of influences in the space environment. One of these is the solar wind, a plasma stream consisting of mostly H⁺ and He²⁺ ions, that impinges on the lunar surface. As a consequence, material is released through the process of ion sputtering, mostly on an atomic level. These ejecta subsequently take part in the formation of the lunar exosphere [1]. Constraining their physical properties, most notably the parameters sputtering yield, ejecta angular distribution and their energy distribution, is thus crucial to properly model the exosphere creation [2]. Such investigations have been of interest for decades and have recently been carried out with samples representative for the lunar mineralogy [3–6].

In this contribution, we present our current investigations on the aforementioned parameters using samples prepared from material collected during the Apollo 16 mission. Using a quartz crystal microbalance (QCM), we are able to measure mass changes due to sputtering caused by H and He ions and therefore also the sputtering yield. Additionally, we place another QCM in the experimentation chamber in a rotatable manner that collects the ejecta. Doing so enables us to probe the angular distribution of the ejecta. For these experiments, we use two types of samples: flat vitreous films as well as pellets pressed from lunar regolith and prepared according to [7]. Along with numerical simulations considering the sample morphology, this allows us to untangle intrinsic material properties from modifications thereof due to surface roughness. Lastly, we will present plans for future measurements to experimentally resolve the ejecta energy distribution. These energy distributions of particles sputtered from compound materials (rather than monatomic ones) are an actively researched area, especially from a numerical standpoint [8–11] – experimental data are scarce, however. This study combining the three physical quantities describing the sputtering process will therefore close a knowledge gap and be applicable not only to the Moon, but also to the sputtering of other planetary bodies.

[1] B. Hapke, J. Geophys. Res. Planets 106 (2001) 10039–10073
[2] P. Wurz, et al., Icarus 191 (2007) 486–496
[3] P.S. Szabo, et al., Icarus 314 (2018) 98–105
[4] H. Biber, et al., Nucl. Instrum. Methods. Phys. Res. B 480 (2020) 10–15
[5] H. Biber, et al., Planet. Sci. J. 3 (2022) 271
[6] M.J. Schaible, et al., J. Geophys. Res. Planets 122 (2017) 1968–1983
[7] N. Jäggi, et al., Icarus 365 (2021) 114492
[8] L.S. Morrissey, et al., J. Appl. Phys. 130 (2021) 013302
[9] H. Hofsäss, A. Stegmaier, Nucl. Instrum. Methods. Phys. Res. B 517 (2022) 49–62
[10] L.S. Morrissey, et al., ApJL 925 (2022) L6
[11] R.M. Killen, et al., Planet. Sci. J. 3 (2022) 139

How to cite: Brötzner, J., Biber, H., Jäggi, N., Nenning, A., Fuchs, L., Szabo, P. S., Galli, A., Wurz, P., and Aumayr, F.: A comprehensive study on the sputtering of the lunar surface, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-18377, https://doi.org/10.5194/egusphere-egu24-18377, 2024.

Discussion Post a comment OSPP judging

Mars

X3.55

EGU24-17142

A 3 Martian Year climatology of aerosols with ExoMars TGO-NOMAD: seasonal cycles and new insights

Giuliano Liuzzi, Geronimo Villanueva, Shohei Aoki, Loic Trompet, Frank Daerden, Lori Neary, Sebastien Viscardy, Sara Faggi, Shane W. Stone, Ian Thomas, Manish Patel, and Ann Carine Vandaele

The Nadir and Occultation for MArs Discovery (NOMAD) spectrometer has been collecting Mars observations since 2018, providing a massive amount of information regarding its atmospheric composition, its vertical structure and bridging the gap between the previous knowledge of the lower atmosphere and the data from other missions (e.g., MAVEN) regarding atmospheric escape. The capability of the Solar Occultation (SO) channel to map the vertical structure of the atmosphere with a very high (>1000) signal-to-noise ratio, at a very high spectral resolution (>17000) and a high vertical sampling (0.5 to 2 km) is valuable in many contexts, ranging from the search for trace species in the lower atmosphere (10 to 40 km) to mapping the isotopic composition of the main atmospheric constituents (H₂O, CO₂, CO) or exploring the vertical structure of dust, water ice and CO₂ ice clouds.

Aerosols are some of the main drivers of the Martian climate, and the study of their spatial distribution and microphysical properties can advance our knowledge of their impact on the climate of the planet and on their formation and dynamics. This work will show the extension of previous investigations focused on dust, water ice and CO₂ ice using NOMAD data, by presenting the mapping of these atmospheric components on a global scale over 3 Martian Years (MY34 Ls 160 to MY37 Ls 170). The acquisition by NOMAD of several diffraction orders during a single occultation allows in fact to obtain spectrally broad information that can be used to map dust and water ice vertical distributions and particle sizes. The information content of NOMAD data about particle sizes of water ice has been demonstrated to be particularly high and to give important information about the nucleation processes of water ice. NOMAD data can also be used to look for CO₂ ice by combining broad spectral information with localized CO₂ ice features at 3600 and 3710 cm^-1, which are well identifiable in the NOMAD spectra.

Besides presenting the climatology of aerosols, we will illustrate specific features occurring during the Martian Year and their repeatability; more specifically, we will look into the differences between MY 34, characterized by a Global Dust Storm, and following years, to highlight the impact of dust-induced heating over cloud formation. We will also give some insights into CO₂ ice cloud formation, which was confirmed to be surprisingly heterogeneous compared to results obtained before TGO operations.

How to cite: Liuzzi, G., Villanueva, G., Aoki, S., Trompet, L., Daerden, F., Neary, L., Viscardy, S., Faggi, S., Stone, S. W., Thomas, I., Patel, M., and Vandaele, A. C.: A 3 Martian Year climatology of aerosols with ExoMars TGO-NOMAD: seasonal cycles and new insights, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-17142, https://doi.org/10.5194/egusphere-egu24-17142, 2024.

X3.56

EGU24-19315

ECS

MSL TLS-SAM measurements consistent with localized methane containment and transport by 3-D atmospheric circulation in Gale crater

Jorge Pla-Garcia, Scot C.R. Rafkin, María Ruíz-Pérez, and Sushil Atreya

The Curiosity rover has traversed more than 30 km from the landing site at the very bottom of Gale crater and has climbed more than ∼750 m into the Mt. Sharp foothills over more than five Martian years. Modeling and observations strongly suggest that the rover has ascended to elevations above a cold pool of air at the bottom of the crater [Ruíz-Pérez et al. 2024 in preparation]. During nighttime, downslope winds originating from both Mt. Sharp and crater rims would prevent the nighttime accumulation of methane released along the slopes above the cold pool and facilitate the convergence and accumulation of methane in the bottom of the crater. As a result, any methane released along the slopes at night is quickly transported downslope. After sunrise, the crater circulation transitions to an upslope regime. The reversal of the circulation should transport the methane accumulated in the bottom of the crater upslope as shown in MRAMS model tracer fields, that also indicate a substantial horizontal mixing that rapidly dilutes the methane-enriched air mass. Any methane released along the slopes is transported horizontally and vented out of the crater. MRAMS model predicts a methane front of peak values to pass higher elevations at increasingly later times after sunrise, moreover later in the morning (~10:00 LMST), but usually with highly and increasingly diluted with time methane values. At mid-morning, upslope circulation along surface rims is fully developed and there is a clear horizontal divergence at bottom of crater where methane is highly diluted due to 3-D atmospheric mixing and increasingly advected upslope out of crater. At dusk, downslope winds starts to develop through sloped surfaces of Mt. Sharp, as well as the cold pool of air at the bottom of the crater, which begins to trap methane released from the ground to start the cycle again. Consistent with [Pla-García et al. 2019] and [Moores et al. 2019] the 3-D crater circulation supplemented by the growth and collapse of the PBL is necessary to explain the TLS-SAM methane observations.

How to cite: Pla-Garcia, J., C.R. Rafkin, S., Ruíz-Pérez, M., and Atreya, S.: MSL TLS-SAM measurements consistent with localized methane containment and transport by 3-D atmospheric circulation in Gale crater, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-19315, https://doi.org/10.5194/egusphere-egu24-19315, 2024.

Discussion Post a comment

X3.57

EGU24-1333

ECS

Atmospheric Tides Near the Equator on Mars

Joonas Leino, Ari-Matti Harri, Don Banfield, Manuel de la Torre Juárez, Mark Paton, Jose-Antonio Rodriguez-Manfredi, Mark Lemmon, and Hannu Savijärvi

Diurnal solar radiation forces global oscillations in pressure, temperature, and wind fields. They are called atmospheric or thermal tides and are additionally modified by topography, surface properties, and atmospheric absorber consentration. They propagate around the planet in periods that are integer fractions of a solar day and are only relevant in the upper atmosphere on Earth, but they represent a very large part of the atmospheric circulation on Mars. First two harmonic components (diurnal and semi-diurnal), with periods of 24 and 12 hr at the locations of InSight and Mars Science Laboratory (MSL) are represented here with the comparison to Mars Climate Database (MCD) predictions.

Both of these landers are located in the tropics, InSight on Elysium Planitia (4.5°N, 135.6°E) and MSL within the Gale Crater (4.6°S, 137.4°E). In this study, we utilized observations of the time period from Martian year (MY) 34 solar longitude (Ls) 296° to MY 36 Ls 53°. Diurnal amplitude was larger than semi-diurnal amplitude on both platforms and similar sensitivity to atmospheric dust content was found. However, the amplitude of the semi-diurnal component was smoother than the diurnal amplitude due to its sensitivity to global atmospheric dust content. One clear difference between the platforms was the average amplitude of the diurnal tide, which was 17 Pa for InSight and 33 Pa for MSL. Lateral hydrostatic adjustment flow, generated by the topography causes this difference since it increases the diurnal range of pressure within the Gale. Diurnal tide phase at the InSight was lower than that at the MSL, with averages of 03:39 and 04:25 LTST. In addition, MSL detected roughly contant diurnal tide phase, but InSight observed much more variation. Semi-diurnal phase pattern was very similar on both platforms.

Diurnal tide amplitude predicted by the MCD mimicked the observations quite well at both locations, except during MY 35 Ls 0°–180°. During that time, MCD amplitudes were lower than observed. This is very likely explained by the atmospheric dust conditions, due to the sensitivity of the diurnal tide to the local atmospheric dust loading. MCD dust optical depth was in good agreement with MSL observed optical depth during MY 35 Ls 180°–360°, but was lower than observed during MY 35 Ls 0°–180°. MCD semi-diurnal amplitudes mimicked the observations well throughout MY 35 due to its sensitivity to global atmospheric dust loading.

How to cite: Leino, J., Harri, A.-M., Banfield, D., de la Torre Juárez, M., Paton, M., Rodriguez-Manfredi, J.-A., Lemmon, M., and Savijärvi, H.: Atmospheric Tides Near the Equator on Mars, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-1333, https://doi.org/10.5194/egusphere-egu24-1333, 2024.

X3.58

EGU24-15145

Vortices and Dust Devils on Jezero Crater, Mars: inner thermal structure and dependence on surface properties

(withdrawn)

Ricardo Hueso, Asier Munguira, Claire Newman, Germán Martínez, Agustín Sánchez-Lavega, Teresa del Río-Gaztelurrutia, Daniel Toledo, Víctor Apéstigue, Ignacio Arruego, Jorge Pla-García, Mark Lemmon, Ralph Lorenz, Álvaro Vicntente-Retortillo, Sara Navarro-López, Alex Stott, Naomi Murdoch, Martin Gillier, Manuel de la Torre-Juárez, and Jose Antonio Rodríguez-Manfredi

X3.59

EGU24-10193

OSPP

New insight into the surface composition of Zhurong landing area

Qing Zhang, John Carter, Mathieu Vincendon, François Poulet, Maxime Pineau, Lin Guo, Yuxuan Luo, Dawei Liu, Jean-Pierre Bibring, Jianjun Liu, and Chunlai Li

The Zhurong rover conducted in-situ spectral investigations of southern Utopia Planitia, where orbital observations revealed the presence of spectrally featureless dust. However, in-situ reflectance spectra collected by the Short Wave Infrared (SWIR) spectrometer exhibit hydrated features for all observations along the traverse. These features have been interpreted as being associated with groundwater (Liu Y. et al., 2022) or ocean (Liu C. et al., 2022; Xiao et al., 2023) or atmospheric water (Zhao et al., 2023). Here, we combine the Multispectral Camera (MSCam) and SWIR data to characterize the spectra of landing site and provide some new insights into the surface composition diversity.

Multispectral images suggest that most of surfaces are consistent with the presence of dust whereas a few of rock surfaces exhibiting dark tones are compositionally distinct. The co-observational SWIR data can be used to further constrain the surface compositions. With Principal Component Analysis (PCA) and unmixing analysis of the SWIR data, we found that these dusty surfaces are ubiquitously characterized with faint 1900 and 2200 nm absorptions and the dark rock surfaces exhibit strong blue slopes in the NIR.

The hydrated dust features seem to contrast with previous knowledge, that the dust does not exhibit obvious NIR hydration features from orbital observations. Such discrepancies were also observed at Jezero crater, where the fine soils or dusty rocks exhibit a 1900 nm H₂O absorption but without 2200 nm band (Mandon et al., 2023). Spectral variation may reflect distinct surface dust compositions between the Perseverance and Zhurong landing site, indicating different dust reservoirs or dust alteration processes. The surface dust of different sites may be mixtures of globally well-mixed fine materials and local/regional distinct hydrated phases. Another possibilities is that the dust underwent different post-deposition aqueous alteration.

The dark rock surfaces may represent less dust-coated surfaces. The strong blue slope features have been previously attributed to coatings on a dark substrate. Furthermore, the morphological properties show that these surfaces exhibit relatively fragile surface context, consistent with surface coatings or rinds.

How to cite: Zhang, Q., Carter, J., Vincendon, M., Poulet, F., Pineau, M., Guo, L., Luo, Y., Liu, D., Bibring, J.-P., Liu, J., and Li, C.: New insight into the surface composition of Zhurong landing area, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-10193, https://doi.org/10.5194/egusphere-egu24-10193, 2024.

OSPP judging

X3.60

EGU24-12597

Monitoring Condensation Flow on Mars with Landed X-ray Spectrometers: A Summary of 11,000 Sols Across Three Landing Sites

Scott VanBommel, Ralf Gellert, Jeff Berger, John Christian, Abigail Knight, Michael McCraig, Cat O'Connell-Cooper, Lucy Thompson, Albert Yen, and Nick Boyd

Alpha Particle X-ray Spectrometers (APXS) were an integral component of the science payload that flew on the twin Mars Exploration Rovers (MER) Spirit and Opportunity. An updated version of the MER APXS instrument, further optimized for in situ geochemical analyses on Mars, is currently operational within Gale crater onboard the Mars Science Laboratory (MSL) rover Curiosity. APXS on MER and MSL were designed and calibrated for high-precision in situ analyses of geologic materials on Mars. The use of curium-244 sources provides high sensitivity to lower-Z elements. This low-Z sensitivity is important for characterizing the abundance of rock forming elements such as Na, but also enables analyses of Ar, which makes up ~2% of the Martian atmosphere, and thus ~40% all non-condensable gas species.

Atmospheric dynamics on Mars are driven in large part by condensation flow. The temperature and pressure at the winter pole leads to the deposition of carbon dioxide (which makes up ~95% of the atmosphere) onto the polar cap. The following spring, carbon dioxide sublimates from the cap, a cycle which creates a pressure gradient across the planet. Non-condensable gases, such as Ar, are not deposited on the polar cap and become enriched relative to carbon dioxide. Most environmental monitoring hardware flown to Mars can measure the absolute pressure of the atmosphere, but not specifically the abundance of non-condensable species. In the case of the Sample Analysis at Mars (SAM) instrument on MSL, atmospheric constituents can be deduced with great accuracy, but not with a high frequency.

We summarize efforts on MER and MSL to characterize variability in non-condensable gas density on Mars using instruments designed to measure the composition of rocks and regolith. Analyses by Spirit enabled calibration of the MER APXS for atmospheric analyses. The Opportunity mission, spanning ~5000 sols, acquired around 2250 hours of atmospheric data with its APXS. This data set revealed an annual short-lived Ar enrichment occurring around L_s 150, previously unreported in the literature and not present in climate models at that time. This phenomenon has since been regularly targeted on MSL with APXS (and SAM), with ~800 hours of atmospheric analyses conducted by APXS thus far. We report recent findings from Mars Year 37, where dedicated high-frequency APXS atmospheric campaigns were conducted, coinciding with solar conjunction and extended holiday plans, significantly improved constraints on the timing of this short-lived enrichment at Gale crater, and compare the observed results to those from Opportunity.

How to cite: VanBommel, S., Gellert, R., Berger, J., Christian, J., Knight, A., McCraig, M., O'Connell-Cooper, C., Thompson, L., Yen, A., and Boyd, N.: Monitoring Condensation Flow on Mars with Landed X-ray Spectrometers: A Summary of 11,000 Sols Across Three Landing Sites, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-12597, https://doi.org/10.5194/egusphere-egu24-12597, 2024.

X3.61

EGU24-7015

ECS

A Linearized Coupled Model of Acoustic-gravity Waves and the Lower Ionosphere at Mars

Xing Wang, Xiaojun Xu, Jun Cui, Siqi Yi, Hao Gu, Zilu Zhou, Hengyan Man, Lei Luo, Peishan He, and Pu Yang

Highly variable ionospheric structures on Mars have been recently observed via spacecraft measurements. Acoustic-gravity waves (AGWs) could be an underlying mechanism. Studying the response of the Martian ionosphere to AGWs could provide us with an important understanding of the neutral wave-ionospheric coupling process. To explore the plasma-neutral coupling driven by AGWs in the lower ionosphere of Mars, a linearized wave model has been developed. This model can describe the propagation and dissipation of AGWs in a realistic atmosphere and first incorporates plasma behaviors associated with photochemistry and electromagnetic fields. We adopted a full-wave model as the first part of our coupled model to delineate wave propagation in a realistic atmosphere. The second part of our model consists of the governing equations describing the plasma behaviors. Therefore, our model not only replicates the result of the full-wave model but also investigates the wave-driven variations in the plasma velocity and density, electromagnetic field, and thermal structures. Our model results reveal that ions are mainly dragged by neutrals and oscillate along the wave phase line below ~200 km altitude. Electrons are primarily subject to gyro-motion along magnetic field lines. The wave-driven distinct motions among charged particles can generate the perturbed electric current and electric field, further contributing to localized magnetic field fluctuations. Major charged constituents, including electrons, O⁺, O₂⁺, and CO₂⁺, have higher density amplitudes when interacting with larger-periodic waves. The presence of photochemistry leads to a decrease in the plasma density amplitude, and there exists a moderate correlation between plasma density variations and those in the neutrals. Our numerical results indicate that the wave-driven variations range from several percent to ~ 80% in the plasma density and from ~ 0.2% to 17% in the magnetic field, which are consistent with the spacecraft observations. Further calculations reveal that the wave-induced plasma-neutral coupling can heat the neutrals yet cool the plasmas. Electrons are cooler than ions in the coupling process. The wave-driven heating by neutral-ion collisions exceeds that by neutral-electron collisions but tends to be lower than the wave dissipative heating and photochemical heating. Our model has potential applications in studying the AGWs-driven variable ionospheric structures and can be used for other planets.

How to cite: Wang, X., Xu, X., Cui, J., Yi, S., Gu, H., Zhou, Z., Man, H., Luo, L., He, P., and Yang, P.: A Linearized Coupled Model of Acoustic-gravity Waves and the Lower Ionosphere at Mars, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-7015, https://doi.org/10.5194/egusphere-egu24-7015, 2024.

X3.62

EGU24-10357

Mars Singular Clouds: Dots, Rings and Narrow-Elongated

Agustin Sanchez-Lavega, Jorge Hernandez-Bernal, Ethan Larsen, Teresa del Rio-Gaztelurrutia, Beatriz Sánchez-Cano, and Anni Määttäanen

We report two extreme cases of clouds in Mars, on the one hand what we call “isolated dot clouds” and on the other hand new cases of extremely “elongated long and narrow clouds” reminiscent in their shape of the one that develops in Arsia Mons. We use the images obtained by the VMC-camera on board the Mars Express mission that from its advantageous polar elliptical orbit allows to image Mars at different local times (in particular at twilight hours).

We present the properties of the “dot clouds” that develop abundantly in the Terra Cimmeria region, particularly around the Kepler crater (longitude 140.9 East and 46.8 South) in Mars solar longitudes Ls from 30 to 100 deg. These are compact rounded clouds with sizes of about 50 km in diameter and altitudes in the range 50-80 km as measured from their shadows. Sometimes they appear isolated at dawn, others in twilight clusters, but we also present a singular case in which they exhibited a ringed shape. We discuss possible mechanisms underlying their formation, such as convection and the possible intervention of the crustal magnetic field concentrated in this region. On the other hand, we report new cases of extremely narrow and elongated clouds observed at mid and high latitudes in both hemispheres. We study in particular the properties of these clouds in the volcanic region of Alba Patera, in Thaumasia Highlands and in Lyot crater, where they can reached lengths from 1,000 km to 2,000 km and widths of 50 km.

How to cite: Sanchez-Lavega, A., Hernandez-Bernal, J., Larsen, E., del Rio-Gaztelurrutia, T., Sánchez-Cano, B., and Määttäanen, A.: Mars Singular Clouds: Dots, Rings and Narrow-Elongated, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-10357, https://doi.org/10.5194/egusphere-egu24-10357, 2024.

X3.63

EGU24-9716

Probing the Mars upper atmosphere through simultaneous NOMAD/UVIS observations of the NO ultraviolet and O2 visible nightglow

Lauriane Soret, Jean-Claude Gérard, Francisco González-Galindo, Ian Thomas, Bojan Ristic, Ann-Carine Vandaele, and Benoit Hubert

While extensive studies have been conducted on Mars' dayside airglow emissions using instruments of various missions (Mariner, Mars Express, MAVEN, TGO and EMM), only the ultraviolet and infrared emissions have been investigated on the nightside (MEx and MAVEN). The middle ultraviolet spectrum is dominated by the v’=0 δ and γ bands of nitric oxide excited by radiative association of nitrogen and oxygen atoms. Although this emission is present at all latitudes and local times, extensive mapping has shown that it is enhanced in winter at high latitudes in both hemispheres (Schneider et al., 2020). This seasonal brightening at high latitudes is the signature of the global transport of O and N atoms ascending from the sunlit summer polar regions that are carried downward by vertical winds and diffusion to the 40-60 km region of the dark winter hemisphere. The O₂ nightglow at 1.27 μm has already been monitored as well (Bertaux et al., 2012). However, nightglow emissions in the visible domain have begun only very recently with the NOMAD-UVIS instrument, which can, for the first time, simultaneously monitor the UV and visible domains in the Martian atmosphere. Gérard et al. (2023) have discovered the presence of the (0,5) to (0,11) bands of the O₂ Herzberg II system between 400 and 650 nm in the nightglow. We present here a comprehensive statistical analysis of this nightglow based on a dedicated NOMAD-UVIS campaign of 30 orbits acquired between May and October 2023 in the southern hemisphere during the winter season. Combining both the inertial and limb tracking modes allows for intensity retrieval, latitudinal variability analysis, and the generation of limb profiles.

The O₂ emission is expected to solely originate from the three-body recombination of O atoms O + O + M → O₂* + M. The oxygen density can therefore directly be retrieved from the Herzberg II observations. Furthermore, simultaneous NO nightglow observations with NOMAD-UVIS combined with the retrieved oxygen density, allows to calculate the nitrogen density and its downward flux. As atomic oxygen serves as a precursor to both NO and O₂ nightglows, arising from O atom recombination with either oxygen or nitrogen, this dual investigation presents a remarkable opportunity to unravel their shared characteristics (stemming from oxygen density) and their distinguishing features (emanating from nitrogen), including variations in brightness and altitudes. It will provide valuable constraints for improving 3-D models that simulate global circulation and dynamic processes. In particular, it will help solving the current discrepancy between the predicted and modeled altitude distribution of the NO nightglow, a proxy of insufficiently vigorous downward transport of N atoms.

References:

Bertaux et al. (2012), First detection of O₂ 1.27 µm nightglow emission at Mars with OMEGA/MEX and comparison with general circulation model predictions, JGR, 117, E00J04, doi:10.1029/2011JE003890.

Gérard et al. (2023). Observation of the Mars O2 visible nightglow by the NOMAD spectrometer onboard the Trace Gas Orbiter. Nature Astronomy, https://doi.org/10.1038/s41550-023-02104-8

Schneider et al. (2020) Imaging of Martian circulation patterns and atmospheric tides through MAVEN/IUVS nightglow observations. JGR Space Physics 125(8), e2019JA027318.

How to cite: Soret, L., Gérard, J.-C., González-Galindo, F., Thomas, I., Ristic, B., Vandaele, A.-C., and Hubert, B.: Probing the Mars upper atmosphere through simultaneous NOMAD/UVIS observations of the NO ultraviolet and O2 visible nightglow, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-9716, https://doi.org/10.5194/egusphere-egu24-9716, 2024.

Discussion Post a comment

X3.64

EGU24-3253

Remote Sensing of Column CO2, Atmospheric Pressure, and Vertical Distribution of Dust and Clouds on Mars using Differential Absorption Lidar at 1.96 µm on an Orbiter

Zhaoyan Liu, Joel Campell, Bing Lin, Jirong Yu, Jihong Geng, and Shibin Jiang

By utilizing progress in millijoule-level pulsed fiber lasers operating in the 1.96 µm spectral range, we propose a novel concept introducing a differential absorption barometric lidar designed for remote sensing of Martian atmospheric properties on an orbiter. Our emphasis is on the online wavelength situated in the trough region of two absorption lines, chosen for its insensitivity to laser frequency variations, thereby mitigating the need for stringent laser frequency stability. Our investigation centers around a compact lidar configuration, featuring reduced telescope dimensions and lower laser pulse energies. These adjustments are aimed at minimizing costs for potential forthcoming Mars missions.

The primary measurement objectives include determining column CO2 absorption optical depth, columnar CO2 abundance, surface atmospheric pressure, as well as vertical distributions of dust and cloud layers. By combining surface pressure data with atmospheric temperature insights obtained from sounders and utilizing the barometric formula, the prospect of deducing atmospheric pressure profiles becomes feasible. Simulation studies validate the viability of our approach. Notably, the precision of Martian surface pressure measurements is projected to better than 1 Pa when the aerial dust optical depth is anticipated to be under 0.7, a typical airborne dust scenario on Mars, considering a horizontal averaging span of 10 km.

How to cite: Liu, Z., Campell, J., Lin, B., Yu, J., Geng, J., and Jiang, S.: Remote Sensing of Column CO2, Atmospheric Pressure, and Vertical Distribution of Dust and Clouds on Mars using Differential Absorption Lidar at 1.96 µm on an Orbiter, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-3253, https://doi.org/10.5194/egusphere-egu24-3253, 2024.

X3.65

EGU24-17539

ECS

OSPP

Martian aerosol Climatology on Mars as Observed by NOMAD UVIS on ExoMars TGO

zachary flimon, Justin Erwin, Severine Robert, Lori Neary, Arianna Piccialli, Loic Trompet, Yannick Willame, Frank Daerden, Sophie Bauduin, Michael Wolff, Ian Thomas, Bojan Ristic, Giancarlo Bellucci, Manish Patel, Cedric Depiesse, Ann-Carine Vandaele, Jon Mason, José juan Lopez-Moreno, and Filip Vanhellemont

The NOMAD (“Nadir and Occultation for MArs Discovery”) spectrometer suite onboard the ExoMars Trace Gas Orbiter (TGO) is composed of three spectrometers. In this work, we will use the UVIS channel in occultation mode. An aerosol climatology had been produced covering the second half of MY 34 up to the end of MY 36.
Aerosols are an important part of the Martian atmosphere and have a strong relationship with the atmospheric temperature. They are composed of dust, H2O ice, and CO2 ice. Dust is the main aerosol and has a significant contribution to the radiative transfer budget, as it absorbs solar radiation, leading to local heating of the atmosphere. Dust is confined to lower altitudes during the aphelion season and can reach higher altitudes during the perihelion, especially during dust storms that frequently arise on Mars during this period. The ice clouds are more present during the aphelion when the temperature is colder and follow a seasonal pattern. Several types of clouds can be found throughout the year, contrary to the dust they reflect the sunlight and cool locally the atmosphere.
Using only the spectral range of UVIS dust, H2O ice, and CO2 ice cannot be differentiated because the three aerosols have similar spectral features in the UV-visible. Dust represents most of the aerosols present in the atmosphere, therefore only dust refractive indices are used in this work. Detection of CO2 and water ice will be investigated in future work using the infrared channel of NOMAD. Nevertheless, we presented a way of indirectly recognizing the composition of the aerosols using indirect parameters such as the temperature or comparison with other datasets.It is possible to distinguish the particle size between 0.1 to 0.8 µm with confidence. When the particles are larger it is not possible to retrieve the precise size.
In conclusion we present a climatology of Martian aerosols, including vertical extinction profiles as well as vertical profiles of particle size distributions. The seasonal cycle of the dust is observed and recurring structures over different Martian years such as dust storms or ice clouds are detected. We also present a comparison with water vapor profiles and aerosol profiles during regional dust storms, we showed that the water vapor during the storm could condense to water ice due to the presence of dust condensation nuclei at high altitudes. The thermal and dynamical structure of the atmosphere, and chemical species are all sensitive to the aerosol’s abundance and size.

How to cite: flimon, Z., Erwin, J., Robert, S., Neary, L., Piccialli, A., Trompet, L., Willame, Y., Daerden, F., Bauduin, S., Wolff, M., Thomas, I., Ristic, B., Bellucci, G., Patel, M., Depiesse, C., Vandaele, A.-C., Mason, J., Lopez-Moreno, J. J., and Vanhellemont, F.: Martian aerosol Climatology on Mars as Observed by NOMAD UVIS on ExoMars TGO, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-17539, https://doi.org/10.5194/egusphere-egu24-17539, 2024.

OSPP judging

Titan

X3.66

EGU24-16561

The Titan PCM : a fully coupled climate model to study thermal structures, haze, clouds and their seasonal variations

Sebastien Lebonnois, Bruno de Batz de Trenquelleon, Lucie Rosset, Jan Vatant d'Ollone, and Pascal Rannou

We have developed a new version of the IPSL Titan GCM, now called the Titan Planetary Climate Model (Titan PCM), including a new microphysical model for haze and clouds. Observations of Titan have long revealed the presence of seasonal cycles on Titan (haze, clouds, organic compounds), the ins and outs of which are still poorly understood. In particular, the lack of information on the different flows that govern these cycles prevents us from understanding all the phenomena taking place in Titan’s atmosphere. The need to develop a complete climate model, including microphysics, therefore becomes essential.

The latest improvements in the Titan PCM radiative transfer, now based on a flexible correlated-k method and up-to-date gases spectroscopic data, lead to a better modelling of the temperature profiles in the middle atmosphere. The photochemical solver extends computation of the composition above the top of the PCM (roughly 500 km) up to 1300 km. Radiative transfer is coupled with a new microphysics model in moments. This model includes phenomena such as the nucleation and condensation of clouds, and precipitation that shape the satellite’s landscape.

We are now able to model the processes involved in the formation of tropospheric (CH4) and polar (C2H2, C2H6 and HCN) clouds on Titan. Cloud formation induces new seasonal cycles, particularly at the tropopause where clouds empty the lower layers of the atmosphere of aerosols, featuring two boundary, the main haze layer and a layer of condensed organic compounds. Higher up, in the lower stratosphere, the haze follows a new cycle constrained solely by the circulation, leading to a better modelling of the temperature profiles in the low stratosphere and the troposphere.

From the results of coupled simulations, we can discuss multiple questions raised by observations. Special interest is bear on the overall control of the thermal structure, and impact of the coupling on equinoctial circulation reversal. We also discuss the radiative destabilization of the lower polar winter stratosphere, observed by Cassini radio-occultations.

How to cite: Lebonnois, S., de Batz de Trenquelleon, B., Rosset, L., Vatant d'Ollone, J., and Rannou, P.: The Titan PCM : a fully coupled climate model to study thermal structures, haze, clouds and their seasonal variations, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-16561, https://doi.org/10.5194/egusphere-egu24-16561, 2024.

Exoplanets

X3.67

EGU24-19629

Modelling Stellar Energetic Particles effects on the atmospheres of terrestrial (exo)planets: INCREASE

Lee Grenfell, Nicolas Iro, Miriam Sinnhuber, Konstantin herbst, Andreas Bartenschlager, Klaus Scherer, and Benjamin Taysum

Posters virtual: Wed, 17 Apr, 14:00–15:45 | vHall X3

Display time: Wed, 17 Apr 08:30–Wed, 17 Apr 18:00

Chairpersons: Arnaud Beth, Shane Carberry Mogan

Mars

vX3.8

EGU24-5955

ECS

Calibration and performance of the MEDA pressure sensor on the Perseverance rover

(withdrawn)

Iina Jaakonaho, Maria Hieta, Maria Genzer, Jouni Polkko, Terhi Mäkinen, Agustín Sánchez-Lavega, Ricardo Hueso, Teresa del Río Gaztelurrutia, Ari-Matti Harri, Harri Haukka, Manuel de la Torre Juárez, and Jose Antonio Rodríguez-Manfredi

vX3.9

EGU24-18637

ECS

OSPP

Interannual Variability of Dust Storms between Mars Years 24 and 36 and analysis of dust vertical distribution of the MY 34 late-storm.

Carolina Martín-Rubio, Alvaro Vicente-Retortillo, Gema Martínez-Esteve, Felipe Gómez, and Jose Antonio Rodríguez-Manfredi

Dust storms on Mars cause variations in atmospheric temperatures and dynamics due to direct solar heating and its dynamic response. These effects are most intense during the dust storm season (Ls 180º - 360º), when most global and regional storms occur and when the suspended dust reaches higher altitudes in the atmosphere. The thermal impact of these events affects the regional and global circulation of Mars. Thanks to measurements taken by the Thermal Emission Spectrometer (TES) onboard the Mars Global Surveyor (MGS) and the Mars Climate Sounder (MCS) onboard the Mars Recoinnasance Orbiter (MRO) it is possible to study the spatial and temporal variability of these storms over the last 12 Martian years (Martín-Rubio et al., 2024). Although each storm must be considered independently, it is possible to observe how the storms recur seasonally following specific patterns that allow them to be grouped according to their time of occurrence and evolution, with the recurrence patterns named as type A, B and C (Kass et al., 2016). Late northern winter large regional storms (C-type storms) show the highest variability; it appears that the occurrence of Global Dust Storms does not have a simple direct effect in the intensity of the subsequent C-type storm. We analyze recent intense type C storms (MY 34, 35 and 36, with particular focus on MY 34, when a Global Dust Storm occurred), studying the vertical, latitudinal and longitudinal dust distribution that occurred between solar longitudes Ls = 318° - 335°. This study is important to better understand the interannual variability of regional dust storms on Mars, as well as dust transport during late northern winter regional storms.

References:

Martín Rubio, C., Vicente-Retortillo, A., Gómez, F. and Rodríguez-Manfredi, J.A., 2024. Interannual variability of Regional Dust Storms between Mars Years 24 and 36, Icarus (under review).

Kass, D. M., Kleinböhl, A., McCleese, D. J., Schofield, J. T., Smith M.D. 2016. Interannual similarity in the Martian atmosphere during the dust storm season

How to cite: Martín-Rubio, C., Vicente-Retortillo, A., Martínez-Esteve, G., Gómez, F., and Rodríguez-Manfredi, J. A.: Interannual Variability of Dust Storms between Mars Years 24 and 36 and analysis of dust vertical distribution of the MY 34 late-storm., EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-18637, https://doi.org/10.5194/egusphere-egu24-18637, 2024.

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