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

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

<p><strong>Introduction:</strong>  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 CO<sub>2</sub> ice, and each have distinct spatiotemporal distributions and radiative effects.</p> <p>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].</p> <p>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’ perihelion season [5] as well as during GDS [6,7].</p> <p>Mars’ low atmospheric temperatures also enable the formation of CO<sub>2</sub> 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].</p> <p> 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’ vertical aerosol structure.</p> <p><strong>Results: </strong>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,<strong> </strong>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’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.</p> <p><strong>References:</strong> [1] Heavens, N. G. et al (2011) <em>JGR (Planets), 116(E4), </em>E04003. [2] Heavens, N. G. et al (2019) <em>GRL, 124</em>(11), 2863-2892. [3] Smith M. D. (2008) <em>Annu. Rev. Earth Planet Sci, 26, </em>191-219. [4] Wang, H. & Ingersoll, A. P. (2002) <em>JGR (Planets), 107(E10), </em>8-1-8-16. [5] Clancy, R. T. et al (2019) <em>Icarus, 328, </em>246-273. [6] Liuzzi G. et al (2020) <em>JGR (Planets), 125</em>(4). [7] Stcherbinine, A. et al (2020) <em>JGR (Planets), 125</em>(3). [8] Aoki, S. et al (2018) <em>Icarus, 302, </em>175-190. [9] Listowski, C. et al (2014) <em>Icarus, 237, </em>239-261. [10] Hayne, P. O. et al (2012) <em>JGR (Planets), 117</em>(E8). [11] Patel, M. R. et al (2017) <em>Appl. Opt., 56</em>(10), 2771-2782. [12] Vandaele, A. C. et al (2015) <em>Planet. Space Sci., 119</em>, 233-249.</p>

A Comparison of Aphelion Cloud Belt Phase Functions Before and After the Mars Year 34 Global Dust Storm

2021 ◽  
Author(s):  
Alex Innanen ◽  
Brittney Cooper ◽  
Charissa Campbell ◽  
Scott Guzewich ◽  
Jacob Kloos ◽  
...  
Keyword(s):  
Dust Storm ◽  
Phase Function ◽  
Dust Storms ◽  
Ice Crystal ◽  
Ice Clouds ◽  
Water Ice ◽  
Ice Cloud ◽  
Sky Survey ◽  
Scattering Phase ◽  
Scattering Phase Function

<p>1. INTRODUCTION</p><p>The Mars Science Laboratory (MSL) is located in Gale Crater (4.5°S, 137.4°E), and has been performing cloud observations for the entirety of its mission, since its landing in 2012 [eg. 1,2,3]. One such observation is the Phase Function Sky Survey (PFSS), developed by Cooper et al [3] and instituted in Mars Year (MY) 34 to determine the scattering phase function of Martian water-ice clouds. The clouds of interest form during the Aphelion Cloud Belt (ACB) season (L<sub>s</sub>=50°-150°), a period of time during which there is an increase in the formation of water-ice clouds around the Martian equator [4]. The PFSS observation was also performed during the MY 35 ACB season and the current MY 36 ACB season.</p><p>Following the MY 34 ACB season, Mars experienced a global dust storm which lasted from L<sub>s</sub>~188° to L<sub>s</sub>~250° of that Mars year [5]. Global dust storms are planet-encircling storms which occur every few Mars years and can significantly impact the atmosphere leading to increased dust aerosol sizes [6], an increase in middle atmosphere water vapour [7], and the formation of unseasonal water-ice clouds [8]. While the decrease in visibility during the global dust storm itself made cloud observation difficult, comparing the scattering phase function prior to and following the global dust storm can help to understand the long-term impacts of global dust storms on water-ice clouds.</p><p>2. METHODS</p><p>The PFSS consists of 9 cloud movies of three frames each, taken using MSL’s navigation cameras, at a variety of pointings in order to observe a large range of scattering angles. The goal of the PFSS is to characterise the scattering properties of water-ice clouds and to determine ice crystal geometry.  In each movie, clouds are identified using mean frame subtraction, and the phase function is computed using the formula derived by Cooper et al [3]. An average phase function can then be computed for the entirety of the ACB season.</p><p><img src="https://contentmanager.copernicus.org/fileStorageProxy.php?f=gnp.eda718c85da062913791261/sdaolpUECMynit/1202CSPE&app=m&a=0&c=67584351a5c2fde95856e0760f04bbf3&ct=x&pn=gnp.elif&d=1" alt="Figure 1 – Temporal Distribution of Phase Function Sky Survey Observations for Mars Years 34 and 35" width="800" height="681"></p><p>Figure 1 shows the temporal distributions of PFSS observations taken during MYs 34 and 35. We aim to capture both morning and afternoon observations in order to study any diurnal variability in water-ice clouds.</p><p>3. RESULTS AND DISCUSSION</p><p>There were a total of 26 PFSS observations taken in MY 35 between L<sub>s</sub>~50°-160°, evenly distributed between AM and PM observations. Typically, times further from local noon (i.e. earlier in the morning or later in the afternoon) show stronger cloud features, and run less risk of being obscured by the presence of the sun. In all movies in which clouds are detected, a phase function can be calculated, and an average phase function determined for the whole ACB season.  </p><p>Future work will look at the water-ice cloud scattering properties for the MY 36 ACB season, allowing us to get more information about the interannual variability of the ACB and to further constrain the ice crystal habit. The PFSS observations will not only assist in our understanding of the long-term atmospheric impacts of global dust storms but also add to a more complete image of time-varying water-ice cloud properties.</p>

Investigating the relationship between ozone and water-ice in the martian atmosphere

2020 ◽  
Author(s):  
Megan Brown ◽  
Manish Patel ◽  
Stephen Lewis ◽  
Amel Bennaceur
Keyword(s):  
Carbon Dioxide ◽  
Water Vapour ◽  
Hydroxyl Radicals ◽  
Atmospheric Chemistry ◽  
Martian Atmosphere ◽  
Reaction Rates ◽  
Chemical Processes ◽  
Ice Clouds ◽  
Water Ice ◽  
The Relationship

<p>This project maps ozone and ice-water clouds detected in the martian atmosphere to assess the atmospheric chemistry between ozone, water-ice and hydroxyl radicals. Hydroxyl photochemistry may be indicated by a non-negative or fluctuating correlation between ozone and water-ice. This will contribute to understanding the stability of carbon dioxide and atmospheric chemistry of Mars.</p><p>Ozone (O<sub>3</sub>) can be used for tracking general circulation of the martian atmosphere and other trace chemicals, as well as acting as a proxy for water vapour. The photochemical break down of water vapour produces hydroxyl radicals known to participate in the destruction of ozone. The relationship between water vapour and ozone is therefore negatively correlated. Atmospheric water-ice concentrations may also follow this theory. The photochemical reactions between ozone, water-ice clouds and hydroxyl radicals are poorly understood in the martian atmosphere due to the short half-life and rapid reaction rates of hydroxyl radicals. These reactions destroy ozone, as well as indirectly contributing to the water cycle and stability of carbon dioxide (measured by the CO<sub>2</sub>–CO ratio). However, the detection of ozone in the presence of water-ice clouds suggests the relationship between them is not always anti-correlated. Global climate models (GCMs) struggle to describe the chemical processes occurring within water-ice clouds. For example, the heterogeneous photochemistry described in the LMD (Laboratoire de Météorologie Dynamique) GCM did not significantly improve the model. This leads to the following questions:<em> what is the relationship between water-ice clouds and ozone, and can the chemical reactions of hydroxyl radicals occurring within water-ice clouds be determined through this relationship?</em></p><p>This project aims to address these questions using nadir and occultation retrievals of ozone and water-ice clouds, potentially using retrievals from the UVIS instrument aboard NOMAD (Nadir and Occultation for Mars Discovery), ExoMars Trace Gas Orbiter. Analysis will include temporal and spatial binning of data to help identify any patterns present. Correlation tests will be conducted to determine the significance of any relationship at short term and seasonal scales along a range of zonally averaged latitude photochemical model from the LMD-UK GCM will be used to further explore the chemical processes.</p><p>Interactions between hydroxyl radicals and the surface of water-ice clouds are poorly understood. Ozone abundance is greatest in the winter at the polar regions, which also coincides with the appearance of the polar hood clouds. The use of nadir observations will enable the comparison between total column of ozone abundance at high latitudes (>60°S) in a range of varying water-ice cloud opacities, as well as the equatorial region (30°S – 30°N) during aphelion. Water-ice clouds may remove hydroxyl radicals responsible for the destruction of ozone and thus the previously assumed anticorrelation between ozone and water-ice will not hold. The project will therefore assess the hypothesis that: <em>water-ice clouds may act as a sink for hydroxyl radicals.</em></p>

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

2020 ◽  
Author(s):  
Ann Carine Vandaele ◽  
Arianna Piccialli ◽  
Ian R. Thomas ◽  
Frank Daerden ◽  
Shohei Aoki ◽  
...  
Keyword(s):  
Spectral Range ◽  
Dust Storm ◽  
Trace Gases ◽  
Martian Atmosphere ◽  
Trace Gas ◽  
Ice Clouds ◽  
Mars Atmosphere ◽  
Solar Occultation ◽  
Composition And Structure

<p>The NOMAD (“Nadir and Occultation for MArs Discovery”) 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 probing the ultraviolet and infrared regions covering large parts of the 0.2-4.3 µm spectral range [1,2].</p><p>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: investigation of the 2018 Global dust storm and its impact on the water uplifting and escape, its impact on temperature increases within the atmosphere as inferred by GCM modeling and observations, the dust and ice clouds distribution during the event, ozone measurements, dayglow observations and in general advances in the analysis of the spectra recorded by the three channels of NOMAD.</p><p>References</p><p>[1] Vandaele, A.C., et al., 2015. Planet. Space Sci. 119, 233-249.</p><p>[2] Vandaele et al., 2018. Space Sci. Rev., 214:80, doi.org/10.1007/s11214-11018-10517-11212.</p>

Retrieval of the water ice column and physical properties of water-ice clouds in the martian atmosphere using the OMEGA imaging spectrometer

Icarus ◽  
2021 ◽  
Vol 353 ◽  
pp. 113229 ◽  
Author(s):  
K.S. Olsen ◽  
F. Forget ◽  
J.-B. Madeleine ◽  
A. Szantai ◽  
J. Audouard ◽  
...  
Keyword(s):  
Physical Properties ◽  
Martian Atmosphere ◽  
Imaging Spectrometer ◽  
Ice Clouds ◽  
Water Ice

scholarly journals Strong Variability of Martian Water Ice Clouds During Dust Storms Revealed From ExoMars Trace Gas Orbiter/NOMAD

2020 ◽  
Vol 125 (4) ◽  
Author(s):  
Giuliano Liuzzi ◽  
Geronimo L. Villanueva ◽  
Matteo M.J. Crismani ◽  
Michael D. Smith ◽  
Michael J. Mumma ◽  
...  
Keyword(s):  
Dust Storms ◽  
Trace Gas ◽  
Ice Clouds ◽  
Water Ice

Water ice clouds in the Martian atmosphere: Two Martian years of SPICAM nadir UV measurements

2009 ◽  
Vol 57 (8-9) ◽  
pp. 1022-1031 ◽  
Author(s):  
N. Mateshvili ◽  
D. Fussen ◽  
F. Vanhellemont ◽  
C. Bingen ◽  
E. Dekemper ◽  
...  
Keyword(s):  
Martian Atmosphere ◽  
Ice Clouds ◽  
Water Ice

scholarly journals Clouds in the Martian Atmosphere

2018 ◽  
Author(s):  
Anni Määttänen ◽  
Franck Montmessin
Keyword(s):  
Martian Atmosphere ◽  
Planetary Science ◽  
Ice Crystals ◽  
Forthcoming Article ◽  
Ice Clouds ◽  
Water Ice ◽  
Ice Nuclei ◽  
Tiny Amount ◽  
Long Time ◽  
Mesospheric Clouds

This is an advance summary of a forthcoming article in the Oxford Research Encyclopedia of Planetary Science. Please check back later for the full article. Although resembling an extremely dry desert, planet Mars hosts clouds in its atmosphere. Every day somewhere on the planet a part of the tiny amount of water vapor held by the atmosphere can condense as ice crystals to form cirrus-type clouds. The existence of water ice clouds has been known for a long time, and they have been studied for decades, leading to the establishment of a well-known climatology and understanding of their formation and properties. Despite their thinness, they have a clear impact on the atmospheric temperatures, thus affecting the Martian climate. Another, more exotic type of clouds forms as well on Mars. The atmospheric temperatures can plunge to such frigid values that the major gaseous component of the atmosphere, CO2, condenses as ice crystals. These clouds form in the cold polar night where they also contribute to the formation of the CO2 ice polar cap, and also in the mesosphere at very high altitudes, near the edge of space, analogously to the noctilucent clouds on Earth. The mesospheric clouds are a fairly recent discovery and have put our understanding of the Martian atmosphere to a test. On Mars, cloud crystals form on ice nuclei, mostly provided by the omnipresent dust. Thus, the clouds link the three major climatic cycles: those of the two major volatiles, H2O and CO2; and that of dust, which is a major climatic agent itself.

Numerical Simulations of the Formation and Evolution of Water Ice Clouds in the Martian Atmosphere

Icarus ◽  
1993 ◽  
Vol 102 (2) ◽  
pp. 261-285 ◽  
Author(s):  
Diane V. Michelangeli ◽  
Owen B. Toon ◽  
Robert M. Haberle ◽  
James B. Pollack
Keyword(s):  
Numerical Simulations ◽  
Martian Atmosphere ◽  
Ice Clouds ◽  
Water Ice ◽  
Formation And Evolution

A new look to the Martian atmosphere

1974 ◽  
Vol 341 (1626) ◽  
pp. 317-330 ◽  
Keyword(s):  
Martian Atmosphere ◽  
Daily Basis ◽  
Dust Storms ◽  
Lower Atmosphere ◽  
Ice Age ◽  
Orbital Eccentricity ◽  
Geological Evidence ◽  
Water Ice ◽  
Local Dust ◽  
Cloud Patterns

Although the Martian atmosphere is at present only about 1% as dense as the Earth’s atmosphere it has been revealed as a dramatically active environment by the observations made during 1971-72 by the Mariner 9 and Soviet Mars 2 and 3 spacecrafts which arrived at the planet during a major global dust storm. Local dust storms were seen to change in intensity on a daily basis and other evidence for winds were seen in cloud patterns and in visible streaks on the planet’s surface. Cloud layers composed of both CO 2 and water ice have been observed. The variations in the albedos of surface markings are probably caused by the wind blow dust. At the present time the lower atmosphere is found to consist mainly of CO 2 with traces of CO, O 3 , O 2 and H 2 O. Geological evidence of channels and gullies suggests erosion by water at some stage of the planet’s development although it is also possible that wind erosion has played a role in sculpturing these features. Periodic variations in the Martian climate may be created through variations in the planets obliquity and orbital eccentricity over time scales of 25000 years. Mars today, then, may be in a temporary ice age.

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