View in EDS

Aerosol Climatology on Mars as Observed by NOMAD UVIS on ExoMars TGO.

Saved in:
Bibliographic Details
Title: Aerosol Climatology on Mars as Observed by NOMAD UVIS on ExoMars TGO.
Authors: Flimon, Z.1,2 (AUTHOR) zachary.flimon@aeronomie.be, Erwin, J.1 (AUTHOR), Robert, S.1 (AUTHOR), Neary, L.1 (AUTHOR), Piccialli, A.1 (AUTHOR), Trompet, L.1 (AUTHOR), Willame, Y.1 (AUTHOR), Vanhellemont, F.1 (AUTHOR), Daerden, F.1 (AUTHOR), Bauduin, S.2 (AUTHOR), Wolff, M.3 (AUTHOR), Thomas, I. R.1 (AUTHOR), Ristic, B.1 (AUTHOR), Mason, J. P.4 (AUTHOR), Depiesse, C.1 (AUTHOR), Patel, M. R.4 (AUTHOR), Bellucci, G.5 (AUTHOR), Lopez‐Moreno, J.‐J.6 (AUTHOR), Vandaele, A. C.1 (AUTHOR)
Source: Journal of Geophysical Research. Planets. Mar2025, Vol. 130 Issue 3, p1-22. 22p.
Subject Terms: *Atmospheric aerosols, *Dust storms, *Trace gases, Martian atmosphere, Mie scattering, Water vapor, Ice clouds
Abstract: 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 us to study the size and extinction of the aerosol as a function of altitude. Results from mid‐MY 34 to the end of MY 36 are reported and discussed. Particle size is retrieved using a Mie code with log‐normal distribution with an effective radius (reff), 0.1–0.8 μm and an effective variance (veff) equal 0.1. In this work, we show the presence of aerosol‐detached layers, characterized by a local increase in particle size and extinction. These detached layers can be composed of dust, H2O ice, or CO2 ice. CO2 ice clouds can be detected up to 80 km, while H2O ice clouds are usually more present around 30–50 km. Symmetry of the particle effective radius between the northern and southern regions is observed. During northern/southern winter, the atmospheric aerosols are composed of smaller particles below 0.6 μm but in summer, the size increases to micron‐sized particles that are larger than the sensitivity of UVIS. This increase in size in the northern/southern summer is not correlated with a similar increase in extinction. Our data support the previously observed relationship between water vapor and aerosol, especially the formation of high‐altitude water ice cloud during the global dust storm event. Plain Language Summary: The Martian atmosphere is composed of several aerosols such as dust, H2O ice and CO2 ice. Using remote sensing measurements from space, we are able to monitor the latitude‐longitude patterns as they evolve across time for 2.5 Martian years. The particle size of aerosols is modeled, but larger particle sizes cannot be detected due to instrument limitations. Aerosols are important because not only do they impact the temperature in the atmosphere by local heating for dust and local cooling for ice clouds but also play a role in the global chemistry. We discuss how it is possible to discern aerosols using the particle size and the local temperature of the atmosphere. A comparison with water vapor profiles during a dust storm shows that water vapor could be found at very high altitudes during these events. Finally, the presence of several ice clouds was observed at different altitudes. We discuss how this work can be built upon in future, combining other observations at different wavelengths to give greater constraints on our data set, allowing us to have better size sensitivity and observation coverage. Key Points: Extinction and size vertical profiles were produced for two and half Martian years from ExoMars TGO/NOMAD‐UVIS solar occultation spectraDerive particle size between 0.1 and 0.8 microns in the UV‐Visible using a Mie scattering codeTemperature and water vapor profiles were used to constrain the composition of aerosols [ABSTRACT FROM AUTHOR]
Copyright of Journal of Geophysical Research. Planets is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
Database: GreenFILE
Description
Abstract: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 us to study the size and extinction of the aerosol as a function of altitude. Results from mid‐MY 34 to the end of MY 36 are reported and discussed. Particle size is retrieved using a Mie code with log‐normal distribution with an effective radius (reff), 0.1–0.8 μm and an effective variance (veff) equal 0.1. In this work, we show the presence of aerosol‐detached layers, characterized by a local increase in particle size and extinction. These detached layers can be composed of dust, H2O ice, or CO2 ice. CO2 ice clouds can be detected up to 80 km, while H2O ice clouds are usually more present around 30–50 km. Symmetry of the particle effective radius between the northern and southern regions is observed. During northern/southern winter, the atmospheric aerosols are composed of smaller particles below 0.6 μm but in summer, the size increases to micron‐sized particles that are larger than the sensitivity of UVIS. This increase in size in the northern/southern summer is not correlated with a similar increase in extinction. Our data support the previously observed relationship between water vapor and aerosol, especially the formation of high‐altitude water ice cloud during the global dust storm event. Plain Language Summary: The Martian atmosphere is composed of several aerosols such as dust, H2O ice and CO2 ice. Using remote sensing measurements from space, we are able to monitor the latitude‐longitude patterns as they evolve across time for 2.5 Martian years. The particle size of aerosols is modeled, but larger particle sizes cannot be detected due to instrument limitations. Aerosols are important because not only do they impact the temperature in the atmosphere by local heating for dust and local cooling for ice clouds but also play a role in the global chemistry. We discuss how it is possible to discern aerosols using the particle size and the local temperature of the atmosphere. A comparison with water vapor profiles during a dust storm shows that water vapor could be found at very high altitudes during these events. Finally, the presence of several ice clouds was observed at different altitudes. We discuss how this work can be built upon in future, combining other observations at different wavelengths to give greater constraints on our data set, allowing us to have better size sensitivity and observation coverage. Key Points: Extinction and size vertical profiles were produced for two and half Martian years from ExoMars TGO/NOMAD‐UVIS solar occultation spectraDerive particle size between 0.1 and 0.8 microns in the UV‐Visible using a Mie scattering codeTemperature and water vapor profiles were used to constrain the composition of aerosols [ABSTRACT FROM AUTHOR]
ISSN:21699097
DOI:10.1029/2024JE008303