Search Publications
Global Transport of Chlorine Species in the Martian Atmosphere and the Resulting Surface Distribution of Perchlorates
Patel, M. R.; Korablev, O.; Olsen, K. S. +5 more
Recent observations by instruments aboard the ExoMars Trace Gas Orbiter (TGO) have revealed the seasonal presence of hydrogen chloride ($\text{HCl}$) in the Martian atmosphere. This discovery may have important implications for Martian photochemistry as chlorine species are chemically active, and it may provide a link between the atmosphere and kn…
Aerosol Climatology on Mars as Observed by NOMAD UVIS on ExoMars TGO
Vandaele, A. C.; Daerden, F.; Thomas, I. R. +16 more
The Nadir and Occultation for MArs Discovery spectrometer on board Trace Gas Orbiter began science operations in April 2018, providing infrared and ultraviolet-visible spectra of the Martian atmosphere. This paper explores the application of the UVIS channel in solar occultation to study aerosols. We have developed a retrieval scheme that allows u…
Climatology and Diurnal Variation of Ozone Column Abundances for 2.5 Mars Years as Measured by the NOMAD-UVIS Spectrometer
Vandaele, A. C.; Daerden, F.; Ristic, B. +14 more
The distribution of Mars ozone (O3) is well established; however, our knowledge on the dayside diurnal variation of O3 is limited. We present measurements of Mars O3 column abundances, spanning Mars Year (MY) 34 to the end of MY 36, by the Ultraviolet and VIsible Spectrometer (UVIS), part of the Nadir and Occultati…
Relationships Between HCl, H2O, Aerosols, and Temperature in the Martian Atmosphere: 1. Climatological Outlook
Patel, M. R.; Montmessin, F.; Fedorova, A. A. +15 more
Detecting trace gases such as hydrogen chloride (HCl) in Mars' atmosphere is among the primary objectives of the ExoMars Trace Gas Orbiter (TGO) mission. Terrestrially, HCl is closely associated with active volcanic activity, so its detection on Mars was expected to point to some form of active magmatism/outgassing. However, after its discovery us…
Relationships Between HCl, H2O, Aerosols, and Temperature in the Martian Atmosphere: 2. Quantitative Correlations
Patel, M. R.; Montmessin, F.; Fedorova, A. A. +15 more
The detection of hydrogen chloride (HCl) in the atmosphere of Mars was among the primary objectives of the ExoMars Trace Gas Orbiter (TGO) mission. Its discovery using the Atmospheric Chemistry Suite mid-infrared channel (ACS MIR) showed a distinct seasonality and possible link to dust activity. This paper is part 2 of a study investigating the li…
The Dynamics of CO2-Driven Granular Flows in Gullies on Mars
Iversen, Jens Jacob; Conway, Susan J.; Kleinhans, Maarten G. +10 more
Martian gullies are landforms consisting of an erosional alcove, a channel, and a depositional apron. A significant proportion of Martian gullies at the mid-latitudes is active today. The seasonal sublimation of CO2 ice has been suggested as a driver behind present-day gully activity. However, due to a lack of in situ observations, the …
The Role and Lifetime of Dissociative Heterogeneous Processes in Improving Simulated Ozone on Mars
Patel, M. R.; Mason, J. P.; Lefèvre, F. +4 more
Ozone simulated in Mars Global Climate Models (MGCMs) is used to assess the underlying chemistry occurring in the atmosphere. Currently, ozone total column abundance (TCA) is under-predicted in MGCMs by up to 120%, implying missing or inaccurate chemistry in models. Heterogeneous reactions of hydroxyl radicals (HOX) have been offered as…
Ultraviolet NO and Visible O2 Nightglow in the Mars Southern Winter Polar Region: Statistical Study and Model Comparison
Vandaele, A. C.; Daerden, F.; Thomas, I. R. +8 more
The Mars NO and the O2 nightglow are produced by the recombination of atoms produced on the dayside by photodissociation and transported to the nightside. These emissions are tracers of the summer to winter pole dynamics in the upper Mars atmosphere. The UV-visible (UVIS) channel of the Nadir and Occultation for MArs Discovery (NOMAD) s…
A Low Albedo, Thin, Resistant Unit in Oxia Planum, Mars: Evidence for an Airfall Deposit and Late-Stage Groundwater Activity at the ExoMars Rover Landing Site
Fawdon, P.; Grindrod, P. M.; Davis, J. M. +2 more
Oxia Planum, Mars, is the future landing site of the ExoMars Rosalind Franklin rover mission, which will search for preserved biosignatures in a phyllosilicate-bearing unit. Overlying the mission-important phyllosilicate-bearing rocks is a dark, capping unit—known here as the Low albedo, Thin, Resistant (LTR) unit—which may have protected the phyl…
A Two-Martian Years Survey of the Water Vapor Saturation State on Mars Based on ACS NIR/TGO Occultations
Montmessin, Franck; Trokhimovskiy, Alexander; Alday, Juan +9 more
On Mars, condensation is the major factor constraining the vertical distribution of water vapor. Recent measurements of water and temperature profiles showed that water can be strongly supersaturated at and above the level where clouds form during the aphelion and perihelion seasons. Since 2018, the near-infrared spectrometer (NIR) of the Atmosphe…