6 Earth Years (3 Martian Years) of Mars Observations by NOMAD on ExoMars TGO
- 1Belgian Institute for Space Aeronomy (BIRA-IASB), Belgium
- 2University of Tokyo, Japan
- 3Open University, UK
- 4Instituto de Astrofisica de Andalucía, CSIC, Spain
- 5Rutherford Appleton Laboratory, UK
- 6IAPS Institute for Space Astrophysics and Planetology, Italy
- *A full list of authors appears at the end of the abstract
On 21st April 2018, the ExoMars Trace Gas Orbiter began its nominal science phase [1]. Since then, for the last 6 and a half years, the NOMAD instrument has taken more than a 100 million spectra in the ultra-violet, visible and infrared.
NOMAD, or “Nadir and Occultation for MArs Discovery”, is a suite of three spectrometers: two operate in the infrared and one operates in the 200-650nm range. Of the two infrared spectrometers, “SO” is designed primarily for solar occultation observations; and “LNO” is primarily designed for nadir observations but can also operate in solar occultation and limb modes [2], and measure Phobos. The ultraviolet-visible spectrometer can do all the above: solar occultation, limb, nadir, and Phobos and Deimos observations [3].
The very high resolving power of the infrared SO and LNO spectrometers (~17000 and ~10000 respectively [4]) mean that they are well suited for measuring atmospheric absorption lines, and are therefore able to measure clouds [5], dust [6], H2O [7], [8], CO [9], [10], CO2 (for temperature and pressure)[11], [12] and HCl [13] in solar occultation mode, plus their isotopes such as HDO [14] and H37CL [15]. SO spectra can also be used to put upper limits on trace gases that are not detected, such as CH4 [16] and HF. In nadir, LNO is primarily measuring H2O [17] and CO [18] in the atmosphere and the albedo/composition of the surface [19], [20]. Work is being done the constrain the potential 2.7µm hydration band in Phobos spectra.
The ultraviolet-visible spectrometer, “UVIS”, measures O3 and dust/aerosols in both solar occultation [21] and nadir modes [22], in addition to Phobos and Deimos [23]. Of particular note is the ongoing work to observe the limb of Mars during both the day and night, to measure the various airglow emission lines present in the limb spectra [24], [25], [26], [27].
Also, calibration efforts are continually ongoing to improve detection limits and retrieval accuracies.
In this presentation we will show the latest results from NOMAD, and describe how scientists outside the NOMAD team can also access all the latest data generated by the instrument.
References
[1] A. C. Vandaele et al., ‘Science objectives and performances of NOMAD’, PSS, 2015, doi: 10.1016/j.pss.2015.10.003.
[2] E. Neefs et al., ‘NOMAD spectrometer on the ExoMars trace gas orbiter mission: part 1—design, manufacturing and testing of the infrared channels’, Appl. Opt., 2015, doi: 10.1364/AO.54.008494.
[3] M. R. Patel et al., ‘NOMAD spectrometer on the ExoMars trace gas orbiter mission: part 2—design, manufacturing, and testing of the ultraviolet and visible channel’, Appl. Opt., 2017, doi: 10.1364/AO.56.002771.
[4] G. Liuzzi et al., ‘Methane on Mars: New insights into the sensitivity of CH4 with the NOMAD/ExoMars spectrometer through its first in-flight calibration’, Icarus, 2019, doi: 10.1016/j.icarus.2018.09.021.
[5] G. Liuzzi et al., ‘First Detection and Thermal Characterization of Terminator CO 2 Ice Clouds With ExoMars/NOMAD’, GRL, 2021, doi: 10.1029/2021GL095895.
[6] A. Stolzenbach et al., ‘Martian Atmospheric Aerosols Composition and Distribution Retrievals During the First Martian Year of NOMAD/TGO Solar Occultation Measurements’, JGR Planets, 2023, doi: 10.1029/2022JE007276.
[7] S. Aoki et al., ‘Global Vertical Distribution of Water Vapor on Mars: Results From 3.5 Years of ExoMars‐TGO/NOMAD Science Operations’, JGR Planets, 2022, doi: 10.1029/2022JE007231.
[8] A. Brines et al., ‘Water Vapor Vertical Distribution on Mars During Perihelion Season of MY 34 and MY 35 With ExoMars‐TGO/NOMAD Observations’, JGR Planets, 2023, doi: 10.1029/2022JE007273.
[9] N. Yoshida et al., ‘Variations in Vertical CO/CO 2 Profiles in the Martian Mesosphere and Lower Thermosphere Measured by the ExoMars TGO/NOMAD: Implications of Variations in Eddy Diffusion Coefficient’, GRL, 2022, doi: 10.1029/2022GL098485.
[10] A. Modak et al., ‘Retrieval of Martian Atmospheric CO Vertical Profiles From NOMAD Observations During the First Year of TGO Operations’, JGR Planets, 2023, doi: 10.1029/2022JE007282.
[11] M. A. López‐Valverde et al., ‘Martian Atmospheric Temperature and Density Profiles During the First Year of NOMAD/TGO Solar Occultation Measurements’, JGR Planets, 2023, doi: 10.1029/2022JE007278.
[12] L. Trompet et al., ‘Carbon Dioxide Retrievals From NOMAD‐SO on ESA’s ExoMars Trace Gas Orbiter and Temperature Profile Retrievals With the Hydrostatic Equilibrium Equation’, JGR Planets, 2023, doi: 10.1029/2022JE007279.
[13] S. Aoki et al., ‘Annual Appearance of Hydrogen Chloride on Mars and a Striking Similarity With the Water Vapor Vertical Distribution Observed by TGO/NOMAD’, GRL, 2021, doi: 10.1029/2021GL092506.
[14] G. L. Villanueva et al., ‘The Deuterium Isotopic Ratio of Water Released From the Martian Caps as Measured With TGO/NOMAD’, GRL, 2022, doi: 10.1029/2022GL098161.
[15] G. Liuzzi et al., ‘Probing the Atmospheric Cl Isotopic Ratio on Mars: Implications for Planetary Evolution and Atmospheric Chemistry’, GRL, 2021, doi: 10.1029/2021GL092650.
[16] E. W. Knutsen et al., ‘Comprehensive investigation of Mars methane and organics with ExoMars/NOMAD’, Icarus, 2021, doi: 10.1016/j.icarus.2020.114266.
[17] M. M. J. Crismani et al., ‘A Global and Seasonal Perspective of Martian Water Vapor From ExoMars/NOMAD’, JGR Planets, 2021, doi: 10.1029/2021JE006878.
[18] M. D. Smith et al., ‘The climatology of carbon monoxide on Mars as observed by NOMAD nadir-geometry observations’, Icarus, 2021, doi: 10.1016/j.icarus.2021.114404.
[19] L. Ruiz Lozano et al., ‘Observation of the Southern Polar cap during MY34-36 with ExoMars-TGO NOMAD LNO’, Icarus, 2024, doi: 10.1016/j.icarus.2023.115698.
[20] F. Oliva et al., ‘Martian CO2 Ice Observation at High Spectral Resolution With ExoMars/TGO NOMAD’, JGR Planets, 2022, doi: 10.1029/2021JE007083.
[21] M. R. Patel et al., ‘ExoMars TGO/NOMAD-UVIS Vertical Profiles of Ozone: 1. Seasonal Variation and Comparison to Water’, JGR Planets, 2021, doi: 10.1029/2021JE006837.
[22] J. P. Mason et al., ‘Climatology and Diurnal Variation of Ozone Column Abundances for 2.5 Mars Years as Measured by the NOMAD-UVIS Spectrometer’, JGR Planets, 2024, doi: 10.1029/2023JE008270.
[23] J. P. Mason et al., ‘Ultraviolet and Visible Reflectance Spectra of Phobos and Deimos as Measured by the ExoMars‐TGO/NOMAD‐UVIS Spectrometer’, JGR Planets, 2023, doi: 10.1029/2023JE008002.
[24] J.-C. Gérard et al., ‘Detection of green line emission in the dayside atmosphere of Mars from NOMAD-TGO observations’, Nat Astron, 2020, doi: 10.1038/s41550-020-1123-2.
[25] J.-C. Gérard et al., ‘First Observation of the Oxygen 630 nm Emission in the Martian Dayglow’, GRL, 2021, doi: 10.1029/2020GL092334.
[26] J.-C. Gérard et al., ‘Observation of the Mars O2 visible nightglow by the NOMAD spectrometer onboard the Trace Gas Orbiter’, Nat Astron, 2024, doi: 10.1038/s41550-023-02104-8.
[27] L. Soret et al., ‘The Ultraviolet Martian Dayglow Observed With NOMAD/UVIS on ExoMars Trace Gas Orbiter’, JGR Planets, 2023, doi: 10.1029/2023JE007762.
The NOMAD Team
How to cite: Thomas, I., Vandaele, A. C., Trompet, L., Aoki, S., Willame, Y., Piccialli, A., Flimon, Z., Daerden, F., Neary, L., Ristic, B., Mason, J., Robert, S., Viscardy, S., Erwin, J., Lopez Valverde, M. A., Patel, M., and Bellucci, G. and the The NOMAD Team: 6 Earth Years (3 Martian Years) of Mars Observations by NOMAD on ExoMars TGO, Europlanet Science Congress 2024, Berlin, Germany, 8–13 Sep 2024, EPSC2024-263, https://doi.org/10.5194/epsc2024-263, 2024.
