Publications

2023 (JGR) https://doi.org/10.1029/2022JE007279

L. Trompet, A.C. Vandaele, I. Thomas, S. Aoki, F. Daerden, J. Erwin, Z. Flimon, A. Mahieux, L. Neary, S. Robert, G. Villanueva, G. Liuzzi, Lopez Valverde, A. Brines, G. Bellucci, J. J. Lopez-Moreno, M. R. Patel

The Solar Occultation (SO) channel of the Nadir and Occultation for Mars Discovery (NOMAD) instrument scans the Martian atmosphere since 21 April 2018. In this work, we present a subset of the NOMAD SO data measured at the mesosphere. We focused on a spectral range that started to be recorded in Martian Year (MY) 35. A total of 968 vertical profiles of carbon dioxide density and temperature covering MY 35 and the beginning of MY 36 are investigated until 135° of solar longitude. We compared 47 profiles with co-located profiles of Mars Climate Sounder onboard Mars Reconnaissance Orbiter. Most profiles show a good agreement as SO temperatures are only 1.8 K higher but some biases lead to an average absolute difference of 7.4°K. The SO dataset is also compared with simulations from GEM-Mars general circulation model. Both datasets are in good agreement except for the presence of a cold layer in the winter hemisphere and a warm layer at dawn in the Northern hemisphere for solar longitudes between 240° to 360°. Five profiles contain temperatures lower than the limit for CO2 condensation. Strong warm layers are found in 13.5% of the profiles. They are present mainly at dawn and in the winter hemisphere while the Northern dusks appear featureless. The dataset mainly covers high latitudes around 60° and we derived some non-migrating tides. In the Southern winter hemisphere, we derived apparent zonal wavenumber-1 and wavenumber-3 tidal components with a maximum amplitude of 10% and 5% at 63 km, respectively.

Panel a) six temperature profiles for diffraction order 148 with some values lower than the temperature limit for CO2
condensation. Panel b) transmittances at pixel 180 corresponding to the profiles in panel a. The second Y-axis provides rough
altitude values.

JGR (2023) https://doi.org/10.1029/2022JE007277

L. Trompet, A.C. Vandaele, I. Thomas, S. Aoki, F. Daerden, J. Erwin, Z. Flimon, A. Mahieux, L. Neary, S. Robert, G. Villanueva, G. Liuzzi, Lopez-Valverde, A. Brines, G. Bellucci, J. J. Lopez-Moreno, M. R. Patel

The SO (Solar Occultation) channel of the Nadir and Occultation for Mars Discovery (NOMAD) instrument has been scanning the Martian atmosphere for almost two Martian years. In this work, we present a subset of the NOMAD SO data measured at the mesosphere at the terminator. From the dataset, we investigated 968 vertical profiles of carbon dioxide density and temperature covering Martian Year (MY) 35 as well as MY 36 up to a solar longitude (Ls) of 135° and altitudes around 60 km to 100 km. While carbon dioxide density profiles are directly retrieved from the spectral signature in the spectra, temperature profiles are more challenging to retrieve as unlike density profiles, temperature profiles can present some spurious features if the regularization is not correctly managed. Comparing seven regularization methods, we found that the expected error estimation method provides the best regularization parameters. The vertical resolution of the profiles is on average 1.6 km. Numerous warm layers and cold pockets appear in this dataset. The warm layers are found in the Northern hemisphere at dawn and dusk as well as in the Southern hemisphere at dawn. Strong warm layers are present in more than 13.5% of the profiles. The Southern hemisphere at dusk does not present any warm layer between Ls 50° and 150°. The height and latitudinal distribution of those warm layers are similar in MY 35 and MY 36 during the first half of the year (Ls=0 - 135°).

Retrieved temperature for a pressure of 0.1 Pa over MY 35 and MY 36 until Ls 135° as a function of solar longitude (panels a and b), as a function of local solar time (panel c), and as a function of latitude (panel d). In Panel a, the color code corresponds to the solar local time, and in panel b to the latitude. Local solar time and latitudinal trends are present in panels a and b.

JGR (2022), https://doi.org/10.1029/2022JE007273

A. Brines, M. A. López-Valverde, A. Stolzenbach, A. Modak, B. Funke, F. G. Galindo, S. Aoki, G. L. Villanueva, G. Liuzzi, I. R. Thomas, J. T. Erwin, U. Grabowski, F. Forget, J. J. Lopez-Moreno, J. Rodriguez-Gomez, F. Daerden, L. Trompet, B. Ristic, M. R. Patel, G. Bellucci, A. C. Vandaele

The water vapor in the Martian atmosphere plays a significant role in the planet’s climate, being crucial in most of the chemical and radiative transfer processes. Despite its importance, the vertical distribution of H2O in the atmosphere has not still been characterized precisely enough. The recent ExoMars Trace Gas Orbiter (TGO) mission, with its Nadir and Occultation for MArs Discovery (NOMAD) instrument, has allowed us to measure the H2O vertical distribution with unprecedented resolution. Recent studies of vertical profiles have shown that high dust concentration in the atmosphere, in particular during dust storms, induces an efficient transport of the H2O to higher altitudes, from 40 km up to 80 km. We study the H2O vertical distribution in a subset of solar occultations during the perihelion of two Martian years (MYs), including the 2018 Global Dust Storm (GDS), in order to compare the same Martian season under GDS and non-GDS conditions. We present our state-of-the-art retrieval scheme, and we apply it to a combination of two diffraction orders, which permits sounding up to about 100 km. We confirm recent findings of H2O increasing at high altitudes during Ls = 190-205° in MY 34, reaching abundances of about 150 ppmv at 80 km in both hemispheres not found during the same period of MY 35. We found a hygropause’s steep rising during the GDS from 30 up to 80 km. Furthermore, strong supersaturation events have been identified at mesospheric altitudes even in presence of water ice layers retrieved by the IAA team.

Seasonal vertical distribution maps of the retrieved water vapor (b,d) during the MY 34 in the Northern (left panels) and the Southern (right panels) hemispheres. The red line indicates the hygropause level. Top panels (a,c) show the latitudes and the Local Solar Time of the observations analyzed.

JGR (2002); https://doi.org/10.1029/2022JE007278

Miguel-Angel López Valverde, Bernd Funke, Adrian Brines, Aurèlien Stolzenbach, Ashimananda Modak, Brittany Hill, Francisco González-Galindo, Ian Thomas, Loic Trompet, Shohei Aoki, Gerónimo Villanueva, Giuliano Liuzzi, Justin Erwin, Udo Grabowski, Francois Forget, José Juan Lopez Moreno, Julio Rodriguez-Gómez, Bojan Ristic, Frank Daerden, Giancarlo Bellucci, Manish Patel, Ann-Carine Vandaele, the NOMAD team

We present vertical profiles of temperature and density from solar occultation (SO) observations by the “Nadir and Occultation for Mars Discovery” (NOMAD) spectrometer on board the Trace Gas Orbiter (TGO) during its first operational year, which covered the second half of Mars Year 34. We used calibrated transmittance spectra in 380 scans, and apply an in-house pre-processing to clean data systematics. Temperature and CO₂ profiles up to about 90 km, with consistent hydrostatic adjustment, are obtained, after adapting an Earth-tested retrieval scheme to Mars conditions. Both pre-processing and retrieval are discussed to illustrate their performance and robustness. Our results reveal the large impact of the MY34 Global Dust Storm (GDS), which warmed the atmosphere at all altitudes. The large GDS aerosols opacity limited the sounding of tropospheric layers. The retrieved temperatures agree well with global climate models (GCM) at tropospheric altitudes, but NOMAD mesospheric temperatures are wavier and globally colder by 10 K in the perihelion season, particularly during the GDS and its decay phase. We observe a warm layer around 80 km during the Southern Spring, especially in the Northern Hemisphere morning terminator, associated to large thermal tides, significantly stronger than in the GCM. Cold mesospheric pockets, close to CO₂ condensation temperatures, are more frequently observed than in the GCM. NOMAD CO₂ densities show oscillations upon a seasonal trend that track well the latitudinal variations expected. Results uncertainties and suggestions to improve future data re-analysis are briefly discussed.

Temperature latitude-solar longitude cross sections at 3 different altitudes, 30 km (left panels), 50 km (central column’s panels) and 80 km (right-hand panels). The retrieved temperatures are shown in the central row, while Latitude-Ls cross sections from the LMD-MGCM are shown in the top panel, for reference.

Planetary and Space Science (2023); https://doi.org/10.1016/j.pss.2023.105638

A. Waza, J. Kjer, M. Peiteado, T. Jardiel, J. Iversen, K. Rasmussen, J. Merrison

In this laboratory investigation, Mars dust analogues have been mobilized by wind flow under Martian conditions of low density CO₂. Various laser based techniques have been employed to quantify dust mobilization and suspension; these include 2D laser Doppler velocimetry, optical opacity and optical reflectance. Direct mobilization of dust has been observed with a threshold shear stress as low as around 0.036 ​± ​0.007 ​Pa though only for dust layers of >1 monolayer and at a flux as high as 220 ​± ​100 ​mg/m²/s at around 20% above threshold. The dust resuspension fluxes for this direct process have been measured to be significantly lower (order of magnitude) than the mobilization rate, typically around 10 ​mg/m²/s at a shear stress of 0.15 ​Pa. This mechanism involved the removal, transport and breakup of dust aggregates. In another mechanism, saltating sand was seen to remobilize deposited dust layers <1 monolayer at a similar mobilization flux of around 50 ​± ​20 ​mg/m²/s and with a threshold of around 0.08 ​± ​0.008 ​Pa. At the high wind speeds used in these studies a significant fraction of the saltating sand grains become transported at relatively high elevation (>10 ​cm) and to high velocity. These essentially suspended grains were seen to generate a large flux of dust through impact abrasion. This constitutes a potential mechanism for dust generation on Mars, though is beyond the scope of this study to isolate and investigate

This is a Photograph series of the dust coated immobile sand beds after exposure to wind flow under Mars simulation conditions.

Planetary Science Journal (2023); 10.3847/PSJ/acf318

T. Becker, J. Teiser, T. Jardiel, M. Peiteado, O. Munoz, J. Martikainen, J. C. Gomez Martin, J. Merrison, and G. Wurm

Our earlier laboratory measurements showed that low-velocity sand impacts release fine 5 μm dust from a Martian simulant soil. This dust will become airborne in the Martian atmosphere. Here, we extend this study by measuring aerodynamic properties of ejecta and characterizing deviations from the behavior of spherical, monolithic grains. We observe the settling of particles emitted as part of an impact splash. The sizes (20 to 280 μm) and sedimentation velocities (0.1 to 0.8 m s−1) of the particles are deduced from high-speed videos while the particles sediment under low ambient pressure of about 1 mbar. The particles regularly settle slower than expected, down to a factor of about 0.3. Using optical microscopy, the shape of the captured particles is characterized by simple axis ratios (longest/smallest), which show that the vast majority of particles are irregular but typically not too elongated, with axis ratios below 2 on average. Electron microscopy further reveals that the particles are typically porous aggregates, which is the most likely reason for the reduction of the sedimentation velocity. Due to the reduced bulk density, aggregates up to 10 μm in diameter should regularly be a part of the dust in the Martian atmosphere.

Sedimentation velocity over geometrical size (measured particle diameter) of the 92 observed particles. The dashed blue line is the freefall velocity from the dust bed height. For small geometrical sizes, the measured sedimentation velocity varies by up to a factor of 5 between nearly same-sized particles, while it decreases for increasing geometrical sizes.

Planet. Sci. J. 3 195   https://doi.org/10.3847/PSJ/ac8477

Becker, T., Teiser J., Jardiel T., Peiteado M., Munoz O., Martikainen J., Gomez Martin J.C., Wurm G.

Emission of dust up to a few microns in size by impacts of sand grains during saltation is thought to be one source of dust within the Martian atmosphere. To study this dust fraction, we carried out laboratory impact experiments. Small numbers of particles of about 200 μm in diameter impacted a simulated Martian soil (bimodal Mars Global Simulant). Impacts occurred at angles of ∼18° in vacuum with an impact speed of ∼1 m s⁻¹. Ejected dust was captured on adjacent microscope slides and the emitted particle size distribution (PSD) was found to be related to the soil PSD. We find that the ejection of clay-sized dust gets increasingly harder the smaller these grains are. However, in spite of strong cohesive forces, individual impacts emit dust of 1 μm and less, i.e., dust in the size range that can be suspended in the Martian atmosphere. More generally, the probability of ejecting dust of a given size can be characterized by a power law in the size range between 0.5 and 5 μm (diameter).

Image of an impact, showing the impactor as a white circle as well as a cloud of ejecta.

JGR (2022); https://doi.org/10.1029/2022JE007231

S. Aoki, A. C. Vandaele, F. Daerden, G. L. Villanueva, G. Liuzzi, R. T. Clancy, M. A. Lopez-Valverde, A. Brines, I. R. Thomas, L. Trompet, J. T. Erwin, L. Neary, S. Robert, A. Piccialli, J. A. Holmes, M. R. Patel, N. Yoshida, J. Whiteway, M. D. Smith, B. Ristic, G. Bellucci, J. J. Lopez-Moreno, A. A. Fedorova

Seasonal variation of the water vapor vertical profiles from LS=160° in MY 34 to LS=130° in MY 36 retrieved from the NOMAD data in the northern hemisphere (the middle panel) and the southern hemisphere (the bottom panel). The retrievals are binned with an interval of 1° of solar longitudes (averaged in latitudes and longitude). The top panel shows the latitudes and local solar time of the measurements (same as Fig. 1). The white represents either no detection or no measurement.

GRL (2022) https://doi.org/10.1029/2022GL098821

F. Daerden, L. Neary, M. J. Wolff, R. T. Clancy, F. Lefèvre, J. A. Whiteway, S. Viscardy, A. Piccialli, Y. Willame, C. Depiesse, S. Aoki, I. R. Thomas, B. Ristic, J. Erwin, J.-C. Gérard, B. J. Sandor, A. Khayat, M. D. Smith, J. P. Mason, M. R. Patel, G. L. Villanueva, G. Liuzzi, G. Bellucci, J.-J. Lopez-Moreno, A. C. Vandaele

The NOMAD/UVIS spectrometer on the ExoMars Trace Gas Orbiter provided observations of ozone and water vapor in the global dust storm of 2018. Here we show in detail, using advanced data filtering and chemical modeling, how Martian ozone in the middle atmosphere was destroyed during the dust storm. In data taken exactly one year later when no dust storm occurred, the normal situation had been reestablished. The model simulates how water vapor is transported to high altitudes and latitudes in the storm, where it photolyses to form odd hydrogen species that catalyze ozone. Ozone destruction is simulated at all latitudes and up to 100 km, except near the surface where it increases. The simulations also predict a strong increase in the photochemical production of atomic hydrogen in the middle atmosphere, consistent with the enhanced hydrogen escape observed in the upper atmosphere during global dust storms.

Latitude-height cross-sections of the simulated number densities of H2O, OH, H, HO2, O and O3 for MY34 (left column) and MY35 (center column), averaged over Ls = 210°–220° (period which falls in the global dust storm (GDS) in MY34). The right column show the ratio of the averaged number densities in MY34 and MY35, except for O3 for which the relative difference is shown. The densities from both years were first interpolated to a common altitude grid as the atmospheric height scale changed during the GDS.

GRL (2022) https://doi.org/10.1029/2022GL098161

Geronimo L. Villanueva, Giuliano Liuzzi, Shohei Aoki, Shane W. Stone, Adrian Brines, Ian R. Thomas, Miguel Angel Lopez-Valverde, Loic Trompet, Justin Erwin, Frank Daerden, Bojan Ristic, Michael D. Smith, Michael J. Mumma, Sara Faggi, Vincent Kofman, Séverine Robert, Lori Neary, Manish Patel, Giancarlo Bellucci, J.-J. Lopez-Moreno, Ann Carine Vandaele

https://doi.org/10.1016/j.icarus.2021.114766 and https://arxiv.org

Felix Jungmann, Maximilian Kruss, Jens Teiser, Gerhard Wurm

Dust emission mechanisms as one aspect of wind-driven particle motion on planetary surfaces are still poorly understood. The microphysics is important though as it determines dust sizes and morphologies which set sedimentation speeds and optical properties. We consider the effects of tribocharging in this context as grains in wind driven granular matter charge significantly. This leads to large electric fields above the granular bed. Airborne dielectric grains are polarized in these electric fields, which leads to attractive forces between grains. To simulate aggregation under these conditions we carried out drop tower experiments using tracer particles, mimicking the gas coupling behavior of small dust grains in terms of high surface to mass ratios and efficient gas drag. Under microgravity, the particles are released into an observation chamber in which an alternating electric field up to 80 kV/m is applied. Without electric field no aggregation can be observed on timescales of seconds. However, polarization instantly leads to aggregation of particles when the field is switched on and long chains aligned to the electric field form. Scaled to dust entrained into planetary atmospheres, fine and coarse grain fractions might readily form aggregates after being liberated. Under certain natural conditions, aggregates might therefore start chain-like or at least a chain-like appearance is favored. If atmospheric influences on their stability are small, aerodynamic and optical properties might depend on this.

Hollow spheres emerging from the shaker.

JGR Planets (2022) https://doi.org/10.1029/2021JE007079

F. Daerden, L. Neary, G. Villanueva, G. Liuzzi, S. Aoki, R. T. Clancy, J. A. Whiteway, B. J. Sandor, M. D. Smith, M. J. Wolff, A. Pankine, A. Khayat, R. Novak, B. Cantor, M. Crismani, M. J. Mumma, S. Viscardy, J. Erwin, C. Depiesse, A. Mahieux, A. Piccialli, S. Robert, L. Trompet, Y. Willame, E. Neefs, I. R. Thomas, B. Ristic, A. C. Vandaele

The vertical profiles of water vapor and its semi-heavy hydrogen isotope HDO provided by instruments on ExoMars Trace Gas Orbiter constitute a unique new data set to understand the Martian water cycle including its isotopic composition. As water vapor undergoes hydrogen isotopic fractionation upon deposition (but not sublimation), the D/H isotopic ratio in water is a tracer of phase transitions, and a key quantity to understand the long-term history of water on Mars. Here, we present 3D global simulations of D/H in water vapor and compare them to the vertically resolved observations of D/H and water ice clouds taken by NOMAD during the second half of Mars year 34. D/H is predicted to be constant with height up to the main cloud level, above which it drops because of strong fractionation, explaining the upper cut-off in the NOMAD observations when HDO drops below detectability. During the global and regional dust storms of 2018/2019, we find that HDO ascends with H2O, and that the D/H ratio is constant and detectable up to larger heights. The simulations are within the provided observational uncertainties over wide ranges in season, latitude and height. Our work provides evidence that the variability of the D/H ratio in the lower and middle atmosphere of Mars is controlled by fractionation on water ice clouds, and thus modulated by diurnally and seasonally varying cloud formation. We find no evidence of other processes or reservoirs that would have a significant impact on the D/H ratio in water vapor.

Overview of NOMAD D/H observations (left) and model simulations (right, MY34 simulation) in three wide latitude ranges. The simulation output was interpolated to the time and location of the observations. The black contour lines show the simulated zonal mean ice mass mixing ratio (in ppmm), averaged over the respective latitude ranges, over all local times and over 5° Ls.

JGR Planets (2022) https://doi.org/10.1029/2021JE007065

Paul M. Streeter, Graham Sellers, Michael J. Wolff, Jonathon P. Mason, Manish R. Patel, Stephen R. Lewis, James A. Holmes, Frank Daerden, Ian R. Thomas, Bojan Ristic, Yannick Willame, Cédric Depiesse, Ann Carine Vandaele, Giancarlo Bellucci, José Juan López-Moreno

The vertical opacity structure of the martian atmosphere is important for understanding the distribution of ice (water and carbon dioxide) and dust. We present a new data set of extinction opacity profiles from the NOMAD/UVIS spectrometer aboard the ExoMars Trace Gas Orbiter, covering one and a half Mars Years (MY) including the MY 34 Global Dust Storm and several regional dust storms. We discuss specific mesospheric cloud features and compare with existing literature and a Mars Global Climate Model (MGCM) run with data assimilation. Mesospheric opacity features, interpreted to be water ice, were present during the global and regional dust events and correlate with an elevated hygropause in the MGCM, providing evidence that regional dust storms can boost transport of vapor to mesospheric altitudes (with potential implications for atmospheric escape). The season of the dust storms also had an apparent impact on the resulting lifetime of the cloud features, with events earlier in the dusty season correlating with longer-lasting mesospheric cloud layers. Mesospheric opacity features were also present during the dusty season even in the absence of regional dust storms, and interpreted to be water ice based on previous literature. The assimilated MGCM temperature structure agreed well with the UVIS opacities, but the MGCM opacity field struggled to reproduce mesospheric ice features, suggesting a need for further development of water ice parameterizations. The UVIS opacity data set offers opportunities for further research into the vertical aerosol structure of the martian atmosphere, and for validation of how this is represented in numerical models.

For MY 34 in the northern hemisphere (top five plots) and southern hemisphere (bottom five plots), from top to bottom: UVIS occultation latitude and local solar time distribution; UVIS occultation opacity profiles at 320–360 nm; total (dust + water ice) opacity profiles from the MGCM run with assimilation, matched to the same locations as the UVIS occultations; atmospheric temperatures from the MGCM run with assimilation, matched to the same locations as the UVIS occultations, and overlaid with black dots indicating the approximate location of the hygropause in the MGCM water vapor field, defined here as 70 ppmv (J. Holmes et al., 2021); ratio of UVIS occultation opacities at 600 nm over 320 nm.

https://doi.org/10.1029/2021GL095895

Giuliano Liuzzi, Geronimo L. Villanueva, Loïc Trompet,Matteo M. J. Crismani,Arianna Piccialli,Shohei Aoki,Miguel Angel Lopez-Valverde,Aurélien Stolzenbach,Frank Daerden,Lori Neary,Michael D. Smith,Manish R. Patel,Stephen R. Lewis,R. Todd Clancy,Ian R. Thomas,Bojan Ristic,Giancarlo Bellucci,Jose-Juan Lopez-Moreno, Ann Carine Vandaele

We present observations of terminator CO₂ ice clouds events in three groups: Equatorial dawn, Equatorial dusk (both between 20°S and 20°N) and Southern midlatitudes at dawn (45°S and 55°S east of Hellas Basin) with ESA ExoMars Trace Gas Orbiter's Nadir and Occultation for MArs Discovery instrument. CO₂ ice abundance is retrieved simultaneously with water ice, dust, and particle sizes, and rotational temperature and CO₂ column profiles in 16 of 26 cases. Small particles (<0.5 μm) prevail at dusk, while water ice likely provides most source nuclei at dawn. Clouds east of Hellas are found to be dominantly nucleated on surface-lifted dust. CO₂ ice is sometimes detected in unsaturated air together with dust nuclei at dawn, suggesting ongoing sublimation. Depending on latitude and local time, the interplay between particle precipitation and the lifetime of temperature minima (i.e., cold pockets) determines CO₂ ice properties.

(a) Summary of the detections in the Equatorial region at dusk, dawn (b) and in the Hellas region at dawn (c). The plots report only the cases in which temperature (and CO₂ saturation ratio, contours) is retrieved together with the properties of dust (orange dots), CO₂ ice (white) and water ice (blue). 

https://doi.org/10.1029/2021JE006834

Alain SJ. Khayat, Michael D. Smith, Michael Wolff, Frank Daerden, Lori Neary, Manish R. Patel, Arianna Piccialli, Ann C. Vandaele, Ian Thomas, Bojan Ristic, Jon Mason, Yannick Willame, Cedric Depiesse, Giancarlo Bellucci, José Juan López-Moreno.

Solar occultations performed by the Nadir and Occultation for MArs Discovery (NOMAD) ultraviolet and visible spectrometer (UVIS) onboard the ExoMars Trace Gas Orbiter (TGO) have provided a comprehensive mapping of atmospheric ozone density. The observations here extend over a full Mars year (MY) between April 21, 2018 at the beginning of the TGO science operations during late northern summer on Mars (MY 34, L_s = 163°) and March 9, 2020 (MY 35). UVIS provided transmittance spectra of the Martian atmosphere allowing measurements of the vertical distribution of ozone density using its Hartley absorption band (200 – 300 nm). The overall comparison to water vapor is found in the companion paper to this work (Patel et al., 2021). Our findings indicate the presence of (1) a high-altitude peak of ozone between 40 and 60 km in altitude over the north polar latitudes for at least 45 % of the Martian year during mid-northern spring, late northern summer-early southern spring, and late southern summer, and (2) a second, but more prominent, high-altitude ozone peak in the south polar latitudes, lasting for at least 60 % of the year including the southern autumn and winter seasons. When present, both high-altitude peaks are observed in the sunrise and sunset occultations, suggesting that the layers could persist during the day. Results from the Mars general circulation models predict the general behavior of these peaks of ozone and are used in an attempt to further our understanding of the chemical processes controlling high-altitude ozone on Mars.

Seasonal distribution of the retrieved vertical O3 abundance (molecules/cm3) in the northern (upper panel) and southern (lower panel) hemispheres. The results are shown after applying a two-dimensional convolution of ∆Ls= 5 ° in the local time dimension (x axis) and ∆? = 3 km in the altitude dimension (y axis). The high-altitude peaks of ozone are visible in both hemispheres during northern spring (southern fall).

https://doi.org/10.1029/2021JE006837  

M. R. Patel, G. Sellers, J. P. Mason, J. A. Holmes, M. A. J. Brown, S. R. Lewis, K. Rajendran, P. M. Streeter, C. Marriner, B. G. Hathi, D. J. Slade, M. R. Leese, M. J. Wolff, A. S. J. Khayat, M. D. Smith, S. Aoki, A. Piccialli, A. C. Vandaele, S. Robert, F. Daerden, I. R. Thomas, B. Ristic, Y. Willame, C. Depiesse, G. Bellucci, J.-J. Lopez-Moreno

We present ∼1.5 Mars Years (MY) of ozone vertical profiles, covering L_S = 163° in MY34 to L_S = 320° in MY35, a period which includes the 2018 global dust storm. Since April 2018, the Ultraviolet and Visible Spectrometer channel of the Nadir and Occultation for Mars Discovery (NOMAD) instrument aboard the ExoMars Trace Gas Orbiter has observed the vertical, latitudinal and seasonal distributions of ozone. Around perihelion, the relative abundance of both ozone and water (from coincident NOMAD measurements) increases with decreasing altitude below ∼40 km. Around aphelion, localized decreases in ozone abundance exist between 25 and 35 km coincident with the location of modeled peak water abundances. High-latitude (>±55°), high altitude (40–55 km) equinoctial ozone enhancements are observed in both hemispheres (L_S ∼350°–40°) and discussed in the companion article to this work (Khayat et al., 2021). The descending branch of the main Hadley cell shapes the observed ozone distribution at L_S = 40°–60°, with the possible signature of a northern hemisphere thermally indirect cell identifiable from L_S = 40°–80°. Morning terminator observations show elevated ozone abundances with respect to evening observations, with average ozone abundances between 20 and 40 km an order of magnitude higher at sunrise compared to sunset, attributed to diurnal photochemical partitioning along the line of sight between ozone and O or fluctuations in water abundance. The ozone retrievals presented here provide the most complete global description of Mars ozone vertical distributions to date as a function of season and latitude.

https://doi.org/10.1029/2021JE006878   http://oro.open.ac.uk/79769/2/Crismani%202021accepted.pdf

Slightly less than a Martian Year of nominal science (March 2018–January 2020) with the ExoMars Trace Gas Orbiter has furthered the ongoing investigation of dayside water vapor column abundance. These dayside observations span latitudes between 75°S and 75°N, and all longitudes, which can provide global snapshots of the total water column abundances. In addition to tracking the seasonal transport of water vapor between poles, geographic enhancements are noted, particularly in the southern hemisphere, both in Hellas Basin, and in other regions not obviously correlated to topography. We report consistent water vapor climatology with previous spacecraft observations, however, note a difference in total water vapor content is noted. Finally, we are unable to find evidence for substantial diurnal variation in the total dayside water vapor column.

 

 

Observations of H2O vapor column abundances, zonally averaged in longitude and scaled by 6 mbar, are presented for solar longitudes from the beginning of nominal science (March 2018) for almost an entire Martian Year (January 2020).

 

The RoadMap project is mentioned in a paper published by The Innovation Platform. It will be available in Issue7 of their Magazine.

The text is however already available on their web site, see here

11 June 2021 - The official magazine of Europlanet, the European community for planetary science, has just been launched.

The first issue of the Europlanet Magazine has been published on line today. The e-Magazine aims to highlight the range of activities carried out by the partners of Europlanet 2024 Research Infrastructure (RI), the members of the Europlanet Society, the Europlanet Early Careers Network, academic and industrial partners, and the wider planetary community. The Magazine is published twice a year in May/June and November/December.

The Europlanet Magazine is funded through the Europlanet 2024 RI project (supported by the European Union’s Horizon 2020 research and innovation programme under grant agreement No 871149). Currently, the Europlanet Magazine is only available online as an e-magazine.

This first issue has a strong focus on Mars, including European contributions to current missions, experimental research in labs and in the field, and outreach initiatives to engage the next generation. It looks back at the origins of Europlanet and its links to the Cassini-Huygens mission at the beginning of this century. It also has updates on the Winchcombe meteorite and on several new partnerships to support planetary science.

Several members of the RoadMap consortium are actively contributing to the Europlanet Society.

One of the articles in this first issue is describing the RoadMp project, see here.