Observations of the Martian atmosphere by NOMAD on ExoMars Trace Gas Orbiter

The NOMAD (&#8220;Nadir and Occultation for MArs Discovery&#8221;) spectrometer suite on board the ExoMars Trace Gas Orbiter has been designed to investigate the composition of Mars' atmosphere, with a particular focus on trace gases, clouds and dust. The instrument probes the ultraviolet and infrared regions covering large parts of the 0.2-4.3 &#181;m spectral range [1,2], with 3 spectral channels: a solar occultation channel (SO &#8211; Solar Occultation; 2.3&#8211;4.3 &#956;m), a second infrared channel capable of nadir, solar occultation, and limb sounding (LNO &#8211; Limb Nadir and solar Occultation; 2.3&#8211;3.8 &#956;m), and an ultraviolet/visible channel (UVIS &#8211; Ultraviolet and Visible Spectrometer, 200&#8211;650 nm). Since its arrival at Mars in April 2018, NOMAD performed solar occultation, nadir and limb observations dedicated to the determination of the composition and structure of the atmosphere. Here we report on the different discoveries highlighted by the instrument during its first full Martian year of observations: investigation of the 2018 Global dust storm and its impact on the water uplifting and escape, on temperature and pressure increases within the atmosphere; dust and ice clouds distribution; ozone measurements; dayglow observations; detection of HCl vertical profiles and in general advances in the analysis of the spectra recorded by the three channels of NOMAD. References [1] Vandaele, A.C., et al., 2015. Planet. Space Sci. 119, 233-249. [2] Vandaele et al., 2018. Space Sci. Rev., 214:80, doi.org/10.1007/s11214-11018-10517-11212.

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The Martian environment observed by NOMAD on ExoMars Trace Gas Orbiter

10.5194/epsc2021-510 ◽

2021 ◽

Author(s):

Ann Carine Vandaele ◽

Frank Daerden ◽

Ian R. Thomas ◽

Shohei Aoki ◽

Cédric Depiesse ◽

...

Keyword(s):

Carbon Monoxide ◽

Trace Gas ◽

Vertical Profiles ◽

Mars Atmosphere ◽

Solar Occultation ◽

Composition And Structure ◽

Spectral Channels ◽

Distribution Water ◽

Infrared Channel

The NOMAD (&#8220;Nadir and Occultation for MArs Discovery&#8221;) spectrometer suite on board the ExoMars Trace Gas Orbiter has been designed to investigate the composition of Mars' atmosphere, with a particular focus on trace gases, clouds and dust. The instrument probes the ultraviolet and infrared regions covering large parts of the 0.2-4.3 &#181;m spectral range [1,2], with 3 spectral channels: a solar occultation channel (SO &#8211; Solar Occultation; 2.3&#8211;4.3 &#956;m), a second infrared channel capable of nadir, solar occultation, and limb sounding (LNO &#8211; Limb Nadir and solar Occultation; 2.3&#8211;3.8 &#956;m), and an ultraviolet/visible channel (UVIS &#8211; Ultraviolet and Visible Spectrometer, 200&#8211;650 nm). Since its arrival at Mars in April 2018, NOMAD performed solar occultation, nadir and limb observations dedicated to the determination of the composition and structure of the atmosphere.NOMAD has been accumulating data about the Martian atmosphere and its surface since its insertion. We will present some results covering the atmosphere composition including clouds and dust, climatologies of water, carbon monoxide and ozone. We also report on the different discoveries highlighted by the instrument by pointing to a series of contributions to this conference that will present in detail several specific studies, like recent progress in the instrument calibration, the latest CO2 and temperature vertical profiles, studies of aerosol nature and distribution, water vapor profiles and variability, carbon monoxide vertical distribution, dayglow observations; detection of HCl, its vertical profiles and in general advances in the analysis of the spectra recorded by the three channels of NOMAD.References[1] Vandaele, A.C., et al., 2015. Planet. Space Sci. 119, 233-249.[2] Vandaele et al., 2018. Space Sci. Rev., 214:80, doi.org/10.1007/s11214-11018-10517-11212.&#160;

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Nadir retrieval of ice clouds and dust from NOMAD/UVIS on board Exomars TGO

10.5194/epsc2021-715 ◽

2021 ◽

Author(s):

Yannick Willame ◽

Jon Mason ◽

Ann C. Vandaele ◽

Justin Erwin ◽

Arianna Piccialli ◽

...

Keyword(s):

Spectral Range ◽

Seasonal Distribution ◽

Trace Gas ◽

Ice Clouds ◽

Mars Atmosphere ◽

Preliminary Results ◽

Aerosol Retrieval ◽

Solar Occultation ◽

Uv Visible ◽

Applied Optics

The NOMAD (&#8220;Nadir and Occultation for MArs Discovery&#8221;) spectrometer suite on board the ExoMars Trace Gas Orbiter (TGO) has been designed to investigate the composition of Mars' atmosphere using a suite of three spectrometers operating in the UV-visible and infrared. NOMAD is a spectrometer operating in ultraviolet (UV), visible and infrared (IR) wavelengths covering large parts of the 0.2-4.3 &#181;m spectral range [1]. The UV-visible &#8220;UVIS&#8221; instrument covers the spectral range from 200 to 650 nm and can perform solar occultation, nadir and limb observations [2]. The main purpose of UVIS is dedicated to the analysis and monitoring of ozone and aerosols such as dust and ice clouds.&#160; In the present work we will present preliminary results of the aerosol retrieval in the UV recorded in nadir geometry: spatial and seasonal distribution of ice clouds and dust. <div> &#160; References [1] Vandaele et al. 2018. Space Sci. Rev. [2] Patel et al., 2017. Applied Optics. </div> &#160;

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Nadir retrieval of ice clouds, dust and ozone from NOMAD/UVIS on board Exomars TGO

10.5194/epsc2020-741 ◽

2020 ◽

Author(s):

Yannick Willame ◽

Ann C. Vandaele ◽

Arianna Piccialli ◽

Cédric Depiesse ◽

Frank Daerden ◽

...

Keyword(s):

Spectral Range ◽

Seasonal Distribution ◽

Trace Gas ◽

Ice Clouds ◽

Mars Atmosphere ◽

Preliminary Results ◽

Solar Occultation ◽

Uv Visible

The NOMAD (&#8220;Nadir and Occultation for MArs Discovery&#8221;) spectrometer suite on board the ExoMars Trace Gas Orbiter (TGO) has been designed to investigate the composition of Mars' atmosphere using a suite of three spectrometers operating in the UV-visible and infrared. NOMAD is a spectrometer operating in ultraviolet (UV), visible and infrared (IR) wavelengths covering large parts of the 0.2-4.3 &#181;m spectral range [1]. The UV-visible &#8220;UVIS&#8221; instrument covers the spectral range from 200 to 650 nm and can perform solar occultation, nadir and limb observations [2]. The main purpose of UVIS is dedicated to the analysis and monitoring of ozone and aerosols such as dust and ice clouds.&#160; In the present work we will present preliminary results of UV retrievals recorded in nadir geometry: spatial and seasonal distribution of ice clouds, dust and ozone.

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Retrievals of dust and ozone from NOMAD-UVIS

10.5194/egusphere-egu2020-16039 ◽

2020 ◽

Author(s):

Arianna Piccialli ◽

Ann Carine Vandaele ◽

Yannick Willame ◽

Cedric Depiesse ◽

Loic Trompet ◽

...

Keyword(s):

Dust Storm ◽

Circulation Model ◽

Dust Storms ◽

Atmospheric Composition ◽

Trace Gas ◽

Global Circulation Model ◽

Global Circulation ◽

Solar Occultation ◽

Composition And Structure ◽

Hydrogen Radicals

We will present two years of observation of dust and ozone vertical distribution obtained from NOMAD-UVIS solar occultations.Atmospheric aerosols are ubiquitous in the Martian atmosphere and they strongly affect the Martian climate [1]. This is particularly true during dust storms. In June 2018, after a pause of 11 years, a planet-encircling dust storm took place on Mars that lasted two months.Ozone, on the other hand, is a species with a short chemical lifetime and characterized by sharp gradients at the day-night terminator due to photolysis [2]. Odd hydrogen radicals play an important role in the destruction of ozone. This results in a strong anti-correlation between O3 and H2O [2].The NOMAD (Nadir and Occultation for MArs Discovery) &#8211; operating onboard the ExoMars 2016 Trace Gas Orbiter satellite &#8211; started to acquire the first scientific measurements on 21 April 2018.It is a spectrometer composed of 3 channels: 1) a solar occultation channel (SO) operating in the infrared (2.3-4.3 &#956;m); 2) a second infrared channel LNO (2.3-3.8 &#956;m) capable of doing nadir, as well as solar occultation and limb; and 3) an ultraviolet/visible channel UVIS (200-650 nm) that can work in the three observation modes [3,4]. The UVIS channel has a spectral resolution <1.5 nm. In the solar occultation mode it is mainly devoted to study the climatology of ozone and aerosols content [5].Since the beginning of operations, on 21 April 2018, NOMAD-UVIS acquired more than 3000 solar occultations with a complete coverage of the planet. NOMAD-UVIS spectra are simulated using the line-by-line radiative transfer code ASIMUT-ALVL developed at IASB-BIRA [6]. In a preliminary study based on SPICAM-UV solar occultations (see [7]), ASIMUT was modified to take into account the atmospheric composition and structure at the day-night terminator. As input for ASIMUT, we used gradients predicted by the 3D GEM-Mars v4 Global Circulation Model (GCM) [8,9].NOMAD will help us improve our knowledge of the climatology of ozone and aerosols. In particular, we will have the rare opportunity to analyze the distribution of aerosols during a dust storm.References:[1] M&#228;&#228;tt&#228;nen, A., Listowski, C., Montmessin, F., Maltagliati, L., Reberac, A., Joly, L., Bertaux, J.L., Apr. 2013. Icarus 223, 892&#8211;941.[2] Lef&#232;vre, F., et al., Aug. 2008. Nature 454, 971&#8211;975.[3] Vandaele, A.C., et al., Planetary and Space Science, Vol. 119,&#160; pp. 233&#8211;249, 2015.[4] Neefs, E., et al., Applied Optics, Vol. 54 (28),&#160; pp. 8494-8520, 2015.[5] M.R. Patel et al., In: Appl. Opt. 56.10 (2017), pp. 2771&#8211;2782. DOI: 10.1364/AO.56.002771.[6] Vandaele, A.C., et al., JGR, 2008. 113 doi:10.1029/2008JE003140.[7] Piccialli, A., Icarus, in press, https://doi.org/10.1016/j.icarus.2019.113598.[8] Neary, L., and F. Daerden (2018), Icarus, 300, 458&#8211;476, doi:10.1016/j.icarus.2017.09.028.[9] Daerden et al., 2019, Icarus 326, https://doi.org/10.1016/j.icarus.2019.02.030

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A new type of cloud discovered from Earth in the upper Martian atmosphere

10.5194/epsc2021-7 ◽

2021 ◽

Author(s):

Jean Lilensten ◽

Jean-Luc Dauvergne ◽

Christophe Pellier ◽

Marc Delcroix ◽

Emmanuel Beaudoin ◽

...

Keyword(s):

High Altitude ◽

Magnetic Anomaly ◽

Dust Storm ◽

Large Scale ◽

Martian Atmosphere ◽

Ice Clouds ◽

Large Particles ◽

Night Side ◽

Cosmic Particle ◽

New Type

During the 2020 Mars opposition, we observe from Earth the occurrence of a non-typical large-scale high-altitude clouds system, extending over thousands of km from the equator to 50&#176;S. Over 3 hours, they emerge from the night side at an altitude of 90 (-15/+30) km and progressively dissipate in the dayside. They occur at a solar longitude of 316&#176;, west of the magnetic anomaly and concomitantly to a regional dust storm. Despite their high altitude, they are composed of relatively large particles, suggesting a probable CO2 ice composition, although H2O cannot be totally excluded. Such ice clouds were not reported previously. We discuss the formation of this new type of clouds and suggest a possible nucleation from cosmic particle precipitation.

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Determination of an effective trace gas mixing height by differential optical absorption spectroscopy (DOAS)

Atmospheric Measurement Techniques Discussions ◽

10.5194/amtd-2-1663-2009 ◽

2009 ◽

Vol 2 (4) ◽

pp. 1663-1692 ◽

Cited By ~ 1

Author(s):

B. Zhou ◽

S. N. Yang ◽

S. S. Wang ◽

T. Wagner

Keyword(s):

Trace Gases ◽

Mixing Layer ◽

Correlation Coefficients ◽

Trace Gas ◽

Optical Absorption Spectroscopy ◽

Gas Mixing ◽

Mixing Height ◽

Free Atmosphere ◽

Layer Height

Abstract. A new method for the determination of the Mixing layer Height (MH) by the DOAS technique is proposed in this article. The MH can be retrieved by a combination of active DOAS and passive DOAS observations of atmospheric trace gases; here we focus on observations of NO2. Because our observations are sensitive to the vertical distribution of trace gases, we refer to the retrieved layer height as an ''effective trace gas mixing height'' (ETMH). By analyzing trace gas observations in Shanghai over one year (1017 hourly means in 93 days in 2007), the retrieved ETMH was found to range between 0.1 km and 2.8 km (average is 0.78 km); more than 90% of the measurements yield an ETMH between 0.2 km and 2.0 km. The seasonal and diurnal variation of the ETMH shows good agreement with mixing layer heights derived from meteorological observations. We investigated the relationship of the derived ETMH to temperature and wind speed and found correlation coefficients of 0.65 and 0.37, respectively. Also the wind direction has an impact on the measurement to some extent. Especially in cases when the air flow comes from highly polluted areas and the atmospheric lifetime of NO2 is long (e.g. in winter), the NO2 concentration at high altitudes over the measurement site can be enhanced, which leads to an overestimation of the ETMH. Enhanced NO2 concentrations in the free atmosphere and heterogeneity within the mixing layer can cause additional uncertainties. Our method could be easily extended to other species like e.g. SO2, HCHO or Glyoxal. Simultaneous studies of these molecules could yield valuable information on their respective atmospheric lifetimes.

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Observations of CO2 clouds on Mars from TIRVIM and NIR solar occultation measurements onboard TGO

10.5194/egusphere-egu21-12721 ◽

2021 ◽

Author(s):

Mikhail Luginin ◽

Nikolay Ignatiev ◽

Anna Fedorova ◽

Alexander Trokhimovskiy ◽

Alexey Grigoriev ◽

...

Keyword(s):

Carbon Dioxide ◽

Atmospheric Chemistry ◽

Near Infrared ◽

Trace Gas ◽

Major Constituent ◽

Russian Science ◽

Geophysical Research ◽

Ice Clouds ◽

Wind Speeds ◽

Solar Occultation

Carbon dioxide is the major constituent of the Martian atmosphere. Its seasonal cycle plays an important role in atmospheric dynamics and climate. Formation of the polar CO2 frost deposits results in up to 30% of atmospheric pressure variations as well as in dramatic change in surface reflectance and emissivity. Another case of carbon dioxide condensation is formation of a CO2 clouds that are still poorly studied, despite the fact that they have been observed by a number of instruments [1&#8722;6] on the orbit of Mars.In this work, we will present first results of CO2 clouds observations from a combination of thermal-infrared (1.7&#8722;17 &#181;m) and near-infrared (0.7-1.6 &#181;m) spectra measured by TIRVIM and NIR instruments onboard the ExoMars Trace Gas Orbiter (TGO) in solar occultation geometry. These instruments are part of the Atmospheric Chemistry Suite (ACS), a set of three spectrometers (NIR, MIR, and TIRVIM) that is conducting scientific measurements on the orbit of Mars since the spring of 2018 [7].This work was funded by Russian Science Foundation, grant number 20-42-09035.References[1] Montmessin et al. (2006). Subvisible CO2 ice clouds detected in the mesosphere of Mars. Icarus, 183, 403&#8211;410. https://doi.org/10.1016/j.icarus.2006.03.015[2] Montmessin et al. (2007). Hyperspectral imaging of convective CO2 ice clouds in the equatorial mesosphere of Mars. Journal of Geophysical Research, 112, E11S90. https://doi.org/10.1029/2007JE002944[3] M&#228;&#228;tt&#228;nen et al. (2010). Mapping the mesospheric CO2 clouds on Mars: MEx/OMEGA and MEx/HRSC observations and challenges for atmospheric models. Icarus, 209, 452&#8211;469. https://doi.org/10.1016/j.icarus.2010.05.017[4] McConnochie et al. (2010). THEMIS-VIS observations of clouds in the Martian mesosphere: Altitudes, wind speeds, and decameter-scale morphology. Icarus, 210, 545&#8211;565. https://doi.org/10.1016/j.icarus.2010.07.021[5] Vincendon et al. (2011). New near-IR observations of mesospheric CO2 and H2O clouds on Mars. Journal of Geophysical Research, 116, E00J02. https://doi.org/10.1029/2011JE003827[6] Jiang et al., (2019). Detection of Mesospheric CO 2 Ice Clouds on Mars in Southern Summer. Geophysical Research Letters, 46(14), 7962&#8211;7971. https://doi.org/10.1029/2019GL082029[7] Korablev et al., (2018). The Atmospheric Chemistry Suite (ACS) of three spectrometers for the ExoMars 2016 Trace Gas Orbiter. Space Sci. Rev. 214, 7. doi:10.1007/s11214-017-0437-6

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Martian Water Ice Clouds During the 2018 Global Dust Storm as Observed by the ACS‐MIR Channel Onboard the Trace Gas Orbiter

Journal of Geophysical Research Planets ◽

10.1029/2019je006300 ◽

2020 ◽

Vol 125 (3) ◽

Cited By ~ 1

Author(s):

A. Stcherbinine ◽

M. Vincendon ◽

F. Montmessin ◽

M. J. Wolff ◽

O. Korablev ◽

...

Keyword(s):

Dust Storm ◽

Trace Gas ◽

Ice Clouds ◽

Water Ice

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Mesospheric water ice clouds in Mars Year 34-35 as identified in ExoMars UVIS occultation opacities

10.5194/epsc2021-725 ◽

2021 ◽

Author(s):

Paul Streeter ◽

Graham Sellers ◽

Mike Wolff ◽

Jon Mason ◽

Manish Patel ◽

...

Keyword(s):

Vertical Distribution ◽

Atmospheric Aerosols ◽

Numerical Models ◽

Martian Atmosphere ◽

Dust Storms ◽

Earth Planet ◽

Ice Clouds ◽

Great Opportunity ◽

Mars Atmosphere ◽

Water Ice

Introduction:&#160; Suspended atmospheric aerosols are key components of the martian atmosphere, and their vertical distribution has long been a subject of investigation with orbital observations and modelling. The aerosols found in Mars' atmosphere are mineral dust, water ice, and CO2 ice, and each have distinct spatiotemporal distributions and radiative effects. Of particular interest for this study is the vertical distribution of atmospheric aerosols. In recent years, dust has been observed to have a more complex vertical distribution structure than previously thought, with the detection of detached dust layers [1] and large plume-like structures during Global Dust Storms (GDS) [2]. Water ice distribution is tied to the seasonal behaviour of its associated cloud formations, with seasonally recurring features including the aphelion cloud belt (ACB) [3] and polar hood clouds [4] at tropospheric altitudes, as well as higher altitude mesospheric (>40 km) clouds during Mars&#8217; perihelion season [5] as well as during GDS [6,7]. Mars&#8217; low atmospheric temperatures also enable the formation of CO2 ice clouds, which have been detected at mesospheric altitudes over the tropics/subtropics and generally during the colder aphelion season [5,8]. These are thought to be more ephemeral than their water ice counterparts, with lifetimes as low as minutes [9]. More persistent and optically thicker CO2 ice clouds have been detected at tropospheric altitudes in the polar night [10]. &#160;The Ultraviolet and Visible (UVIS) Spectrometer [11], part of the Nadir and Occultation for MArs Discovery (NOMAD) spectrometer suite aboard the ExoMars Trace Gas Orbiter (TGO) [12], has now observed the martian atmospheric limb via solar occultations for over 1.5 martian years. This period covers the 2018/Mars Year (MY) 34 GDS and regional dust storm, as well as the entirety of the more typical MY 35. As such, UVIS solar occultation data provides a great opportunity to examine Mars&#8217; vertical aerosol structure. Results: We present a new UVIS occultation opacity profile dataset, openly available for use by the community. We also discuss particular features of interest in the dataset, and interpret these features by reference to previous published work and by comparison with the MGCM. In particular, we focus on notable mesospheric water ice cloud phenomena observed in both MY 34 and MY 35. We describe the spatiotemporal distribution of these features, and the link between specific water ice features and strong atmospheric dust activity from global and regional storms. The MGCM temperature and aerosol opacity fields provide valuable points of comparison with the UVIS dataset, for the purposes of both explanation and validation of the MGCM&#8217;s existing parametrizations. The UVIS dataset offers opportunities for further research into the vertical aerosol structure of the martian atmosphere, and improvement of how this is represented in numerical models. References: [1] Heavens, N. G. et al (2011) JGR (Planets), 116(E4), E04003. [2] Heavens, N. G. et al (2019) GRL, 124(11), 2863-2892. [3] Smith M. D. (2008) Annu. Rev. Earth Planet Sci, 26, 191-219. [4] Wang, H. & Ingersoll, A. P. (2002) JGR (Planets), 107(E10), 8-1-8-16. [5] Clancy, R. T. et al (2019) Icarus, 328, 246-273. [6] Liuzzi G. et al (2020) JGR (Planets), 125(4). [7] Stcherbinine, A. et al (2020) JGR (Planets), 125(3). [8] Aoki, S. et al (2018) Icarus, 302, 175-190. [9] Listowski, C. et al (2014) Icarus, 237, 239-261. [10] Hayne, P. O. et al (2012) JGR (Planets), 117(E8). [11] Patel, M. R. et al (2017) Appl. Opt., 56(10), 2771-2782. [12] Vandaele, A. C. et al (2015) Planet. Space Sci., 119, 233-249.

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