Search Publications
Revealing a High Water Abundance in the Upper Mesosphere of Mars With ACS Onboard TGO
Montmessin, Franck; Belyaev, Denis A.; Fedorova, Anna A. +7 more
We present the first water vapor profiles encompassing the upper mesosphere of Mars, 100-120 km, far exceeding the maximum altitudes where remote sensing has been able to observe water to date. Our results are based on solar occultation measurements by Atmospheric Chemistry Suite (ACS) onboard the ExoMars Trace Gas Orbiter (TGO). The observed wave…
Annual Appearance of Hydrogen Chloride on Mars and a Striking Similarity With the Water Vapor Vertical Distribution Observed by TGO/NOMAD
Aoki, S.; Vandaele, A. C.; Daerden, F. +23 more
Hydrogen chloride (HCl) was recently discovered in the atmosphere of Mars by two spectrometers onboard the ExoMars Trace Gas Orbiter. The reported detection made in Martian Year 34 was transient, present several months after the global dust storm during the southern summer season. Here, we present the full data set of vertically resolved HCl detec…
First Detection and Thermal Characterization of Terminator CO2 Ice Clouds With ExoMars/NOMAD
Vandaele, Ann Carine; Stolzenbach, Aurélien; Aoki, Shohei +16 more
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 retrie…
Probing the Atmospheric Cl Isotopic Ratio on Mars: Implications for Planetary Evolution and Atmospheric Chemistry
Vandaele, Ann Carine; Aoki, Shohei; Liuzzi, Giuliano +22 more
Following the recent detection of HCl in the atmosphere of Mars by ExoMars/Trace Gas Orbiter, we present here the first measurement of the 37Cl/35Cl isotopic ratio in the Martian atmosphere using a set of Nadir Occultation for MArs Discovery (NOMAD) observations. We determine an isotopic anomaly of −6 ± 78‰ compared to Earth …
Enhanced Super-Rotation Before and During the 2018 Martian Global Dust Storm
Fedorova, Anna A.; Holmes, James A.; Lewis, Stephen R. +3 more
Super-rotation affects—and is affected by—the distribution of dust in the martian atmosphere. We modeled this interaction during the 2018 global dust storm (GDS) of Mars Year 34 using data assimilation. Super-rotation increased by a factor of two at the peak of the GDS, as compared to the same period in the previous year which did not feature a GD…
First Observation of the Oxygen 630 nm Emission in the Martian Dayglow
Aoki, S.; Vandaele, A. C.; Daerden, F. +13 more
Following the recent detection of the oxygen green line airglow on Mars, we have improved the statistical analysis of the data recorded by the NOMAD/UVIS instrument on board the ExoMars Trace Gas Orbiter mission by summing up hundreds of spectra to increase the signal to noise ratio. This led to the observation of the OI 630 nm emission, the first…
Active Boulder Falls in Terra Sirenum, Mars: Constraints on Timing and Causes
Conway, Susan J.; Grindrod, Peter M.; Davis, Joel M. +1 more
We use time series images to identify significant active boulder falls in an impact crater on Mars. Evidence for active boulder falls include boulder trails with impact marks from bouncing and rolling, and dark patches from boulder impacts away from the base of the crater walls. We were able to define three time periods with active boulder falls a…