Water vapor vertical distributions on Mars: Results from three years of TGO/NOMAD science operations

<div> Nadir and Occultation for Mars Discovery (NOMAD) onboard ExoMars Trace Gas Orbiter (TGO) started&#160; science measurements on 21 April, 2018. Here, we present results on the retrievals of water vapor vertical distributions in the Martian atmosphere from three years of TGO/NOMAD science operations. </div> &#160; NOMAD is a spectrometer operating in the spectral ranges between 0.2 and 4.3 &#956;m onboard ExoMars TGO. NOMAD has 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). The infrared channels (SO and LNO) have high spectral resolution (&#955;/d&#955;~10,000&#8211;20,000) provided by an echelle grating used in combination with an Acousto Optic Tunable Filter (AOTF) which selects diffraction orders. The sampling rate for the solar occultation measurement is 1 second, which provides a good vertical sampling step (~1 km) with higher resolution (~2 km) from the surface to 200 km. Thanks to the instantaneous change of the observing diffraction orders achieved by the AOTF, the SO channel is able to measure five or six different diffraction orders per second in solar occultation mode. In this study, we analyze the solar occultation measurements at diffraction order 134 (3011-3035 cm-1), order 136 (3056-3080 cm-1), order 168 (3775-3805 cm-1), and order 169 (3798-3828 cm-1) acquired by the SO channel in order to investigate water vapor vertical distributions. Knowledge of the water vapor vertical profile is important to understand the water cycle and its escape process. Solar occultation measurements by two new spectrometers onboard TGO - NOMAD and Atmospheric Chemistry Suite (ACS) - allows us to daily monitor the water vapor vertical distributions through the whole Martian Year and obtain a good latitudinal coverage for every ~20&#176; of Ls. In 2018, for the first time after 2007, a global dust storm occurred on Mars. It lasted for more than two months (from June to August). Moreover, following the global dust storm, a regional dust storm occurred in January 2019. The NOMAD and ACS observations therefore fully cover the majority of the global and regional dust storms and offer a unique opportunity to study the trace gases distributions during the dust storms. We analyzed those datasets and found a significant increase of water vapor abundances in the middle atmosphere (40-100 km) during the global dust storm from June to mid-September 2018 and the regional dust storm in January 2019. In particular, water vapor reaches very high altitude, at least 100 km, during the global dust storm (Aoki et al., 2019, Journal of Geophysical Research, Volume124, Issue12, Pages 3482-3497, doi:10.1029/2019JE006109). A GCM simulation explained that dust storm related increases of atmospheric temperatures suppress the hygropause, hence reducing ice cloud formation and so allowing water vapor to extend into the middle atmosphere (Neary et al., 2020, Geophysical Research Letters, accepted, Volume47, Issue7, e2019GL084354, doi: 10.1029/2019GL084354). This study presents the results with the extended dataset, which covers a full Mars year. The extended dataset newly includes aphelion season that involves interesting phenomena such as sublimation of water vapor from the northern polar cap and formation of the equatorial cloud belt, which are known as key periods to understand the large north-south hemispheric asymmetries of Mars water vapor. Yet, only a few papers report the water vapor vertical distributions in the aphelion season. The extended dataset also includes the southern summer season (dusty season) in MY 35, which will allow us to compare the water vapor distributions in the global dust storm year with those in the non-global dust storm year. In the presentation, we will discuss the water vapor vertical profiles as well as the aerosols vertical distributions retrieved from the three-year measurements of the TGO/NOMAD.

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Water vapor vertical profiles on Mars: Results from the first full Mars Year of TGO/NOMAD science operations

10.5194/epsc2020-392 ◽

2020 ◽

Author(s):

Shohei Aoki ◽

AnnCarine Vandaele ◽

Frank Daerden ◽

Geronimo Villanueva ◽

Ian Thomas ◽

...

Keyword(s):

Water Vapor ◽

Vertical Distribution ◽

Dust Storm ◽

Middle Atmosphere ◽

Dust Storms ◽

High Spectral Resolution ◽

Vertical Profiles ◽

Geophysical Research ◽

Solar Occultation ◽

Science Operations

Nadir and Occultation for Mars Discovery (NOMAD) onboard ExoMars Trace Gas Orbiter (TGO) started the science measurements on 21 April, 2018. We present results on the retrievals of water vapor vertical profiles in the Martian atmosphere from the first Mars year measurements of the TGO/NOMAD.NOMAD is a spectrometer operating in the spectral ranges between 0.2 and 4.3 &#956;m onboard ExoMars TGO. NOMAD has 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). The infrared channels (SO and LNO) have high spectral resolution (&#955;/d&#955;~10,000&#8211;20,000) provided by an echelle grating used in combination with an Acousto Optic Tunable Filter (AOTF) which selects diffraction orders. The concept of the infrared channels are derived from the Solar Occultation in the IR (SOIR) instrument onboard Venus Express (VEx). The sampling rate for the solar occultation measurement is 1 second, which provides better vertical sampling step (~1 km) with higher resolution (~2 km) from the surface to 200 km. Thanks to the instantaneous change of the observing diffraction orders achieved by the AOTF, the SO channel is able to measure five or six different diffraction orders per second in solar occultation mode. In this study, we analyze the solar occultation measurements at diffraction order 134 (3011-3035 cm-1), order 136 (3056-3080 cm-1) and 168 (3775-3805 cm-1) acquired by the SO channel in order to investigate H2O vertical profiles.Knowledge of the water vapor vertical distribution is important to understand the water cycle and escape processes. Solar occultation measurements by the two spectrometers onboard TGO - NOMAD and Atmospheric Chemistry Suite (ACS) - allow us to monitor daily the water vapor vertical profiles through one whole Martian Year and obtain a latitudinal map for every ~20&#176; of Ls. In 2018, for the first time after 2007, a global dust storm occurred on Mars. It lasted for more than two months (from June to August). Moreover, following the global dust storm, a regional dust storm occurred in January 2019. TGO began its science operations on 21 April 2018. NOMAD observations therefore fully cover the period before/during/after the global and regional dust storms and offer a unique opportunity to study the trace gases distributions during such events. We have analyzed those datasets and found a significant increase of water vapor abundance in the middle atmosphere (40-100 km) during the global dust storm from June to mid-September 2018 and the regional dust storm in January 2019. In particular, water vapor reaches very high altitudes, at least 100 km, during the global dust storm (Aoki et al., 2019, Journal of Geophysical Research, Volume124, Issue12, Pages 3482-3497, doi:10.1029/2019JE006109). A GCM simulation explained that dust storm related increases of atmospheric temperatures suppress the hygropause, hence reducing ice cloud formation and so allowing water vapor to extend into the middle atmosphere (Neary et al., 2020, Geophysical Research Letters, 47, e2019GL084354., doi: 10.1029/2019GL084354). The current study presents the results obtained when considering the extended dataset, which covers a full Martian year. The extended dataset includes the recent aphelion season that involves interesting phenomena such as sublimation of water vapor from the northern polar cap and formation of the equatorial cloud belt, and is known as a key period to understand the large north-south hemispheric asymmetries of Mars water vapor. Yet, until now, only few papers reported the water vapor vertical distribution during the aphelion season. The extended dataset also includes the period when the global dust storm occurred the year before; this will allow us to compare the water vapor distributions under global dust storm conditions with those found during non-global dust storm years. In the presentation, we will discuss the H2O vertical profiles as well as the aerosols vertical distribution retrieved from the first full Martian year measurements of the TGO/NOMAD. How to cite: Aoki, S., Vandaele, A., Daerden, F., Villanueva, G., Thomas, I., Erwin, J., Trompet, L., Robert, S., Neary, L., Viscardy, S., Piccialli, A., Liuzzi, G., Crismani, M., Clancy, T., Smith, M., Ristic, B., Lopez-Valverde, M.-A., Patel, M., Bellucci, G., and Lopez-Moreno, J.-J.: Water vapor vertical profiles on Mars: Results from the first full Mars Year of TGO/NOMAD science operations, Europlanet Science Congress 2020, online, 21 September&#8211;9 Oct 2020, EPSC2020-392, 2020

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On the role of dust storms in triggering atmospheric gravity waves observed in the middle atmosphere

Annales Geophysicae ◽

10.5194/angeo-29-1647-2011 ◽

2011 ◽

Vol 29 (9) ◽

pp. 1647-1654 ◽

Cited By ~ 7

Author(s):

S. K. Das ◽

A. Taori ◽

A. Jayaraman

Keyword(s):

Gravity Waves ◽

Dust Storm ◽

Hot Spots ◽

Middle Atmosphere ◽

Thermal Structure ◽

Dust Storms ◽

Storm Events ◽

Atmospheric Perturbations ◽

Atmospheric Gravity

Abstract. Lower atmospheric perturbations often produce measurable effects in the middle and upper atmosphere. The present study demonstrates the response of the middle atmospheric thermal structure to the significant enhancement of the lower atmospheric heating effect caused by dust storms observed over the Thar Desert, India. Our study from multi-satellite observations of two dust storm events that occurred on 3 and 8 May 2007 suggests that dust storm events produce substantial changes in the lower atmospheric temperatures as hot spots which can become sources for gravity waves observed in the middle atmosphere.

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An Observational Overview of Dusty Deep Convection in Martian Dust Storms

Journal of the Atmospheric Sciences ◽

10.1175/jas-d-19-0042.1 ◽

2019 ◽

Vol 76 (11) ◽

pp. 3299-3326 ◽

Cited By ~ 6

Author(s):

Nicholas G. Heavens ◽

David M. Kass ◽

James H. Shirley ◽

Sylvain Piqueux ◽

Bruce A. Cantor

Keyword(s):

Dust Storm ◽

Large Scale ◽

Middle Atmosphere ◽

Deep Convection ◽

High Surface ◽

Dust Storms ◽

Radiative Heating ◽

Storm Activity ◽

Mesoscale Circulations ◽

Convective Structures

Abstract Deep convection, as used in meteorology, refers to the rapid ascent of air parcels in Earth’s troposphere driven by the buoyancy generated by phase change in water. Deep convection undergirds some of Earth’s most important and violent weather phenomena and is responsible for many aspects of the observed distribution of energy, momentum, and constituents (particularly water) in Earth’s atmosphere. Deep convection driven by buoyancy generated by the radiative heating of atmospheric dust may be similarly important in the atmosphere of Mars but lacks a systematic description. Here we propose a comprehensive framework for this phenomenon of dusty deep convection (DDC) that is supported by energetic calculations and observations of the vertical dust distribution and exemplary dusty deep convective structures within local, regional, and global dust storm activity. In this framework, DDC is distinct from a spectrum of weaker dusty convective activity because DDC originates from preexisting or concurrently forming mesoscale circulations that generate high surface dust fluxes, oppose large-scale horizontal advective–diffusive processes, and are thus able to maintain higher dust concentrations than typically simulated. DDC takes two distinctive forms. Mesoscale circulations that form near Mars’s highest volcanoes in dust storms of all scales can transport dust to the base of the upper atmosphere in as little as 2 h. In the second distinctive form, mesoscale circulations at low elevations within regional and global dust storm activity generate freely convecting streamers of dust that are sheared into the middle atmosphere over the diurnal cycle.

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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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Water vapor in the middle atmosphere of Mars during the 2007 global dust storm

Icarus ◽

10.1016/j.icarus.2017.09.025 ◽

2018 ◽

Vol 300 ◽

pp. 440-457 ◽

Cited By ~ 39

Author(s):

Anna Fedorova ◽

Jean-Loup Bertaux ◽

Daria Betsis ◽

Franck Montmessin ◽

Oleg Korablev ◽

...

Keyword(s):

Water Vapor ◽

Dust Storm ◽

Middle Atmosphere

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Trajectories of Major Martian Dust Storms

10.5194/egusphere-egu2020-9223 ◽

2020 ◽

Author(s):

Huiqun (Helen) Wang ◽

Mark Richardson ◽

Anthony Toigo

Keyword(s):

Optical Depth ◽

Dust Storm ◽

General Circulation ◽

Middle Atmosphere ◽

Thermal Structure ◽

Great Variability ◽

Dust Storms ◽

The Past ◽

Annual Variability

&#160;&#160;&#160;&#160;&#160; Major dust storms &#8211; including large regional and global dust storms &#8211; dramatically influence atmospheric optical depth, thermal structure, and circulation. They represent probably the most significant inter-annual variability in the Martian lower / middle atmosphere and are of particular concern for spacecraft missions. Great variability is exhibited not only in their timing and magnitudes, but also in histories of their evolution. Mars Daily Global Maps (MDGMs) over the past Mars decade have shown that all major dust storms develop through a combination of dust storm sequences evolving along one or more trajectories, where each dust storm sequence is composed of multiple dust storm members of various sizes and durations along a trajectory. In this presentation, we will illustrate the trajectories of major dust storms observed in MDGMs and examine their relationship with the general circulation.

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Impact of atmospheric gravity waves on the Martian global water cycle during dust storms

10.5194/egusphere-egu21-5562 ◽

2021 ◽

Author(s):

Dmitry Shaposhnikov ◽

Alexander Medvedev ◽

Alexander Rodin ◽

Paul Hartogh

Keyword(s):

Water Vapor ◽

Gravity Waves ◽

Dust Storm ◽

Water Cycle ◽

Dust Storms ◽

Upper Atmosphere ◽

Atmospheric Gravity Waves ◽

Global Water Cycle ◽

Atmospheric Gravity ◽

Global Water

Effects of atmospheric gravity waves (GWs) on the global water cycle in the middle and high atmosphere of Mars during the global dust storms (Martian years 28 and 34) have been studied for the first time using a general circulation model. Dust storm simulations were compared with those utilizing the climatological distribution of dust in the absence of a GW parameterization. The dust storm scenarios are based on the observations of the dust optical depth by the Mars Climate Sounder instrument on board Mars Reconnaissance Orbiter. The simulations show that accounting for the influence of GWs leads to a change in the concentration of water vapor in the thermosphere. The most significant effect of GWs is twofold. First, cooling of the thermosphere at the poles leads to a decrease in the water vapor abundance during certain periods. Second, heating in the regions representing the main channels of water supply to the upper atmosphere (the so-called water "pump" mechanism) increases, on the contrary, its concentration. Since the temperature increase provides more intensive atmospheric mixing, and also expands the supply channel through an increase in saturation pressure. The dynamic balance of these basic mechanisms drives the changes in the distribution of water vapor in the upper atmosphere. Dust storms enhance pumping of water vapor into the upper atmosphere. Seasonal differences in the storm occurrences in different years allow for tracking the paths of water vapor transport to the upper atmosphere.

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Estimation of Vertical Distributions of Water Vapor and Aerosols from Spaceborne Observations of Scattered Sunlight

10.21236/ada610165 ◽

2000 ◽

Author(s):

Dale P. Winebrenner ◽

John Sylvester

Keyword(s):

Water Vapor ◽

Vertical Distributions

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Dust Transport from Inland Australia and Its Impact on Air Quality and Health on the Eastern Coast of Australia during the February 2019 Dust Storm

Atmosphere ◽

10.3390/atmos12020141 ◽

2021 ◽

Vol 12 (2) ◽

pp. 141

Author(s):

Emilie Aragnou ◽

Sean Watt ◽

Hiep Nguyen Duc ◽

Cassandra Cheeseman ◽

Matthew Riley ◽

...

Keyword(s):

Air Quality ◽

Dust Storm ◽

New South ◽

New South Wales ◽

The State ◽

Dust Storms ◽

Eastern Coast ◽

Storm Event ◽

South Wales ◽

Dust Storm Event

Dust storms originating from Central Australia and western New South Wales frequently cause high particle concentrations at many sites across New South Wales, both inland and along the coast. This study focussed on a dust storm event in February 2019 which affected air quality across the state as detected at many ambient monitoring stations in the Department of Planning, Industry and Environment (DPIE) air quality monitoring network. The WRF-Chem (Weather Research and Forecast Model—Chemistry) model is used to study the formation, dispersion and transport of dust across the state of New South Wales (NSW, Australia). Wildfires also happened in northern NSW at the same time of the dust storm in February 2019, and their emissions are taken into account in the WRF-Chem model by using Fire Inventory from NCAR (FINN) as emission input. The model performance is evaluated and is shown to predict fairly accurate the PM2.5 and PM10 concentration as compared to observation. The predicted PM2.5 concentration over New South Wales during 5 days from 11 to 15 February 2019 is then used to estimate the impact of the February 2019 dust storm event on three health endpoints, namely mortality, respiratory and cardiac disease hospitalisation rates. The results show that even though as the daily average of PM2.5 over some parts of the state, especially in western and north western NSW near the centre of the dust storm and wild fires, are very high (over 900 µg/m3), the population exposure is low due to the sparse population. Generally, the health impact is similar in order of magnitude to that caused by biomass burning events from wildfires or from hazardous reduction burnings (HRBs) near populous centres such as in Sydney in May 2016. One notable difference is the higher respiratory disease hospitalisation for this dust event (161) compared to the fire event (24).

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