Stormy water on Mars: The distribution and saturation of atmospheric water during the dusty season

The loss of water from Mars to space is thought to result from the transport of water to the upper atmosphere, where it is dissociated to hydrogen and escapes the planet. Recent observations have suggested large, rapid seasonal intrusions of water into the upper atmosphere, boosting the hydrogen abundance. We use the Atmospheric Chemistry Suite on the ExoMars Trace Gas Orbiter to characterize the water distribution by altitude. Water profiles during the 2018–2019 southern spring and summer stormy seasons show that high-altitude water is preferentially supplied close to perihelion, and supersaturation occurs even when clouds are present. This implies that the potential for water to escape from Mars is higher than previously thought.

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Photolysis controls the isotopic composition of water products escaping Mars’ atmosphere

10.21203/rs.3.rs-128379/v1 ◽

2021 ◽

Author(s):

Juan Alday ◽

Alexander Trokhimovskiy ◽

Patrick Irwin ◽

Colin Wilson ◽

Franck Montmessin ◽

...

Keyword(s):

Atmospheric Chemistry ◽

Isotope Composition ◽

Relative Proportion ◽

Upper Atmosphere ◽

Trace Gas ◽

Main Process ◽

Deuterated Water ◽

Ion Chemistry ◽

Mars Atmosphere ◽

Photolysis Rates

Abstract The current Martian atmosphere is about five times more enriched in deuterium than Earth's, providing a direct testimony that Mars hosted several times more water in its early youth than nowadays. Estimates of the total amount of water lost to space from the current mean D/H value depend on a rigorous appraisal of the relative escape between deuterated and non-deuterated water. The transport of water to the upper atmosphere, from whence it may escape to space, has been assumed to be controlled by water condensation and photolysis, both of which affect the isotope composition of the escaping hydrogen. Their respective role in influencing the relative proportion of escaping D and H atom populations in the upper atmosphere has remained speculative. Here we report HDO and H<2sub>O profiles observed by the Atmospheric Chemistry Suite (ExoMars Trace Gas Orbiter) in orbit around Mars that, once combined with expected photolysis rates, reveal that the ultraviolet dissociation of water not only governs the production of atomic hydrogen, prevailing over the ion chemistry mechanism, but also dominates the production of H relative to D atoms, disrupting the old paradigm of atmospheric condensation being the main process differentiating D and H in the upper atmosphere.

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Case studies of the impact of orbital sampling on stratospheric trend detection and derivation of tropical vertical velocities: solar occultation vs. limb emission sounding

Atmospheric Chemistry and Physics ◽

10.5194/acp-16-11521-2016 ◽

2016 ◽

Vol 16 (18) ◽

pp. 11521-11534 ◽

Cited By ~ 9

Author(s):

Luis F. Millán ◽

Nathaniel J. Livesey ◽

Michelle L. Santee ◽

Jessica L. Neu ◽

Gloria L. Manney ◽

...

Keyword(s):

Case Studies ◽

Atmospheric Chemistry ◽

Stratospheric Ozone ◽

Sampling Bias ◽

Nonuniform Sampling ◽

Trend Detection ◽

Trace Gas ◽

Uniform Sampling ◽

Solar Occultation ◽

The Impact

Abstract. This study investigates the representativeness of two types of orbital sampling applied to stratospheric temperature and trace gas fields. Model fields are sampled using real sampling patterns from the Aura Microwave Limb Sounder (MLS), the HALogen Occultation Experiment (HALOE) and the Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS). The MLS sampling acts as a proxy for a dense uniform sampling pattern typical of limb emission sounders, while HALOE and ACE-FTS represent coarse nonuniform sampling patterns characteristic of solar occultation instruments. First, this study revisits the impact of sampling patterns in terms of the sampling bias, as previous studies have done. Then, it quantifies the impact of different sampling patterns on the estimation of trends and their associated detectability. In general, we find that coarse nonuniform sampling patterns may introduce non-negligible errors in the inferred magnitude of temperature and trace gas trends and necessitate considerably longer records for their definitive detection. Lastly, we explore the impact of these sampling patterns on tropical vertical velocities derived from stratospheric water vapor measurements. We find that coarse nonuniform sampling may lead to a biased depiction of the tropical vertical velocities and, hence, to a biased estimation of the impact of the mechanisms that modulate these velocities. These case studies suggest that dense uniform sampling such as that available from limb emission sounders provides much greater fidelity in detecting signals of stratospheric change (for example, fingerprints of greenhouse gas warming and stratospheric ozone recovery) than coarse nonuniform sampling such as that of solar occultation instruments.

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Dynamics and composition of the Asian summer monsoon anticyclone

10.5194/acp-2017-420 ◽

2017 ◽

Cited By ~ 1

Author(s):

Klaus-Dirk Gottschaldt ◽

Hans Schlager ◽

Robert Baumann ◽

Duy S. Cai ◽

Veronika Eyring ◽

...

Keyword(s):

Summer Monsoon ◽

Atmospheric Chemistry ◽

Asian Summer Monsoon ◽

Monsoon Season ◽

Lower Troposphere ◽

Equatorial Region ◽

Ozone Production ◽

Trace Gas ◽

Asian Summer ◽

Southern Fringe

Abstract. This study places HALO research aircraft observations in the upper-tropospheric Asian summer monsoon anticyclone (ASMA) obtained during the Earth System Model Validation (ESMVal) campaign in September 2012 into the context of regional, intra-annual variability by hindcasts with the ECHAM/MESSy Atmospheric Chemistry (EMAC) model. The simulations demonstrate that tropospheric trace gas profiles in the monsoon season are distinct from the rest of the year. Air uplifted from the lower troposphere to the tropopause layer dominates the eastern part of the ASMA’s interior, while the western part is characterised by subsidence down to the mid-troposphere. Soluble compounds are being washed out when uplifted by convection in the eastern part, where lightning simultaneously replenishes reactive nitrogen in the upper troposphere. Net photochemical ozone production is significantly enhanced in the ASMA, contrasted by an ozone depleting regime in the mid-troposphere and more neutral conditions in autumn and winter. An analysis of multiple monsoon seasons in the simulation shows that stratospherically influenced tropopause layer air is regularly entrained at the eastern ASMA flank, and then transported in the southern fringe around the interior region. Observed and simulated tracer-tracer relations reflect photochemical O3 production, as well as in-mixing from the lower troposphere and the tropopause layer. The simulation additionally shows entrainment of clean air from the equatorial region by northerly winds at the western ASMA flank. Although the in situ measurements were performed towards the end of summer, the main ingredients needed for their interpretation are present throughout the monsoon season. A transition between two dynamical modes of the ASMA took place during the HALO ESMVal campaign. Transport barriers of the original anticyclone are overcome effectively when it splits up. Air from the fringe is stirred into the interiors of the new anticyclones and vice versa. Instabilities of this and other types occur quite frequently. Our study emphasises their paramountcy for the trace gas composition of the ASMA and its outflow into regions around the world.

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The high Arctic in extreme winters: vortex, temperature, and MLS and ACE-FTS trace gas evolution

Atmospheric Chemistry and Physics ◽

10.5194/acp-8-505-2008 ◽

2008 ◽

Vol 8 (3) ◽

pp. 505-522 ◽

Cited By ~ 62

Author(s):

G. L. Manney ◽

W. H. Daffer ◽

K. B. Strawbridge ◽

K. A. Walker ◽

C. D. Boone ◽

...

Keyword(s):

Atmospheric Chemistry ◽

Lower Stratosphere ◽

High Arctic ◽

Trace Gas ◽

Satellite Measurements ◽

Broadband Emission ◽

Gas Measurements ◽

Chemistry Experiment ◽

Very High ◽

Good Agreement

Abstract. The first three Arctic winters of the ACE mission represented two extremes of winter variability: Stratospheric sudden warmings (SSWs) in 2004 and 2006 were among the strongest, most prolonged on record; 2005 was a record cold winter. Canadian Arctic Atmospheric Chemistry Experiment (ACE) Validation Campaigns were conducted at Eureka (80° N, 86° W) during each of these winters. New satellite measurements from ACE-Fourier Transform Spectrometer (ACE-FTS), Sounding of the Atmosphere using Broadband Emission Radiometry (SABER), and Aura Microwave Limb Sounder (MLS), along with meteorological analyses and Eureka lidar temperatures, are used to detail the meteorology in these winters, to demonstrate its influence on transport, and to provide a context for interpretation of ACE-FTS and validation campaign observations. During the 2004 and 2006 SSWs, the vortex broke down throughout the stratosphere, reformed quickly in the upper stratosphere, and remained weak in the middle and lower stratosphere. The stratopause reformed at very high altitude, near 75 km. ACE measurements covered both vortex and extra-vortex conditions in each winter, except in late-February through mid-March 2004 and 2006, when the strong, pole-centered vortex that reformed after the SSWs resulted in ACE sampling only inside the vortex in the middle through upper stratosphere. The 2004 and 2006 Eureka campaigns were during the recovery from the SSWs, with the redeveloping vortex over Eureka. 2005 was the coldest winter on record in the lower stratosphere, but with an early final warming in mid-March. The vortex was over Eureka at the start of the 2005 campaign, but moved away as it broke up. Disparate temperature profile structure and vortex evolution resulted in much lower (higher) temperatures in the upper (lower) stratosphere in 2004 and 2006 than in 2005. Satellite temperatures agree well with lidar data up to 50–60 km, and ACE-FTS, MLS and SABER show good agreement in high-latitude temperatures throughout the winters. Consistent with a strong, cold upper stratospheric vortex and enhanced radiative cooling after the SSWs, MLS and ACE-FTS trace gas measurements show strongly enhanced descent in the upper stratospheric vortex in late January through March 2006 compared to that in 2005.

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Validation of MIPAS IMK/IAA methane profiles

Atmospheric Measurement Techniques ◽

10.5194/amt-8-5251-2015 ◽

2015 ◽

Vol 8 (12) ◽

pp. 5251-5261 ◽

Cited By ~ 16

Author(s):

A. Laeng ◽

J. Plieninger ◽

T. von Clarmann ◽

U. Grabowski ◽

G. Stiller ◽

...

Keyword(s):

Atmospheric Chemistry ◽

Michelson Interferometer ◽

European Space Agency ◽

Trace Gas ◽

Mixing Ratios ◽

Air Sampler ◽

Solar Occultation ◽

Space Agency ◽

Scanning Imaging ◽

Satellite Instruments

Abstract. The Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) is an infrared (IR) limb emission spectrometer on the Envisat platform. It measures trace gas distributions during day and night, pole-to-pole, over an altitude range from 6 to 70 km in nominal mode and up to 170 km in special modes, depending on the measurement mode, producing more than 1000 profiles day−1. We present the results of a validation study of methane, version V5R_CH4_222, retrieved with the IMK/IAA (Institut für Meteorologie und Klimaforschung, Karlsruhe/Instituto de Astrofisica de Andalucia, Grenada) MIPAS scientific level 2 processor. The level 1 spectra are provided by the ESA (European Space Agency) and version 5 was used. The time period covered is 2005–2012, which corresponds to the period when MIPAS measured trace gas distributions at a reduced spectral resolution of 0.0625 cm−1. The comparison with satellite instruments includes the Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS), the HALogen Occultation Experiment (HALOE), the Solar Occultation For Ice Experiment (SOFIE) and the SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY (SCIAMACHY). Furthermore, comparisons with MkIV balloon-borne solar occultation measurements and with air sampling measurements performed by the University of Frankfurt are presented. The validation activities include bias determination, assessment of stability, precision validation, analysis of histograms and comparison of corresponding climatologies. Above 50 km altitude, MIPAS methane mixing ratios agree within 3 % with ACE-FTS and SOFIE. Between 30 and 40 km an agreement within 3 % with SCIAMACHY has been found. In the middle stratosphere, there is no clear indication of a MIPAS bias since comparisons with various instruments contradict each other. In the lower stratosphere (below 25 km) MIPAS CH4 is biased high with respect to satellite instruments, and the most likely estimate of this bias is 14 %. However, in the comparison with CH4 data obtained from cryogenic whole-air sampler (cryosampler) measurements, there is no evidence of a high bias in MIPAS between 20 and 25 km altitude. Precision validation is performed on collocated MIPAS–MIPAS pairs and suggests a slight underestimation of its uncertainties by a factor of 1.2. No significant evidence of an instrumental drift has been found.

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First detection of ozone in the mid-infrared at Mars: implications for methane detection

Astronomy and Astrophysics ◽

10.1051/0004-6361/202038125 ◽

2020 ◽

Vol 639 ◽

pp. A141 ◽

Cited By ~ 3

Author(s):

K. S. Olsen ◽

F. Lefèvre ◽

F. Montmessin ◽

A. Trokhimovskiy ◽

L. Baggio ◽

...

Keyword(s):

Atmospheric Chemistry ◽

Polar Vortex ◽

Trace Gas ◽

Spectral Signature ◽

Infrared Range ◽

Mid Infrared ◽

Northern Latitudes ◽

Ultraviolet Range ◽

Vibration Rotation ◽

Methane Detection

Aims. The ExoMars Trace Gas Orbiter was sent to Mars in March 2016 to search for trace gases diagnostic of active geological or biogenic processes. Methods. We report the first observation of the spectral features of Martian ozone (O3) in the mid-infrared range using the Atmospheric Chemistry Suite Mid-InfaRed (MIR) channel, a cross-dispersion spectrometer operating in solar occultation mode with the finest spectral resolution of any remote sensing mission to Mars. Results. Observations of ozone were made at high northern latitudes (>65°N) prior to the onset of the 2018 global dust storm (Ls = 163–193°). During this fast transition phase between summer and winter ozone distribution, the O3 volume mixing ratio observed is 100–200 ppbv near 20 km. These amounts are consistent with past observations made at the edge of the southern polar vortex in the ultraviolet range. The observed spectral signature of ozone at 3000–3060 cm−1 directly overlaps with the spectral range of the methane (CH4) ν3 vibration-rotation band, and it, along with a newly discovered CO2 band in the same region, may interfere with measurements of methane abundance.

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Oxygen isotopic ratios in Martian water vapour observed by ACS MIR on board the ExoMars Trace Gas Orbiter

Astronomy and Astrophysics ◽

10.1051/0004-6361/201936234 ◽

2019 ◽

Vol 630 ◽

pp. A91 ◽

Cited By ~ 2

Author(s):

J. Alday ◽

C. F. Wilson ◽

P. G. J. Irwin ◽

K. S. Olsen ◽

L. Baggio ◽

...

Keyword(s):

Water Vapour ◽

Atmospheric Chemistry ◽

Trace Gas ◽

Oxygen Isotope Ratios ◽

Infrared Measurements ◽

History Of ◽

Oxygen Isotopic ◽

Atmospheric Loss ◽

The Impact ◽

First Time

Oxygen isotope ratios provide important constraints on the history of the Martian volatile system, revealing the impact of several processes that might fractionate them, such as atmospheric loss into space or interaction with the surface. We report infrared measurements of the Martian atmosphere obtained with the mid-infrared channel (MIR) of the Atmospheric Chemistry Suite (ACS), onboard the ExoMars Trace Gas Orbiter. Absorption lines of the three main oxygen isotopologues of water vapour (H216O, H218O, and H217O) observed in the transmission spectra allow, for the first time, the measurement of vertical profiles of the 18O/16O and 17O/16O ratios in atmospheric water vapour. The observed ratios are enriched with respect to Earth-like values (δ18O = 200 ± 80‰ and δ17O = 230 ± 110‰ corresponding to the Vienna Standard Mean Ocean Water). The vertical structure of these ratios does not appear to show significant evidence of altitudinal variations.

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Aerosol extinction profiles at 525 nm and 1020 nm derived from ACE imager data: comparisons with GOMOS, SAGE II, SAGE III, POAM III, and OSIRIS

Atmospheric Chemistry and Physics ◽

10.5194/acp-8-2027-2008 ◽

2008 ◽

Vol 8 (7) ◽

pp. 2027-2037 ◽

Cited By ~ 16

Author(s):

F. Vanhellemont ◽

C. Tetard ◽

A. Bourassa ◽

M. Fromm ◽

J. Dodion ◽

...

Keyword(s):

Atmospheric Chemistry ◽

Trace Gas ◽

Aerosol Extinction ◽

Optical Extinction ◽

Solar Occultation ◽

Comparison Results ◽

Stellar Occultation ◽

Relative Differences ◽

Atmospheric Trace Gas ◽

Chemistry Experiment

Abstract. The Canadian ACE (Atmospheric Chemistry Experiment) mission is dedicated to the retrieval of a large number of atmospheric trace gas species using the solar occultation technique in the infrared and UV/visible spectral domain. However, two additional solar disk imagers (at 525 nm and 1020 nm) were added for a number of reasons, including the retrieval of aerosol and cloud products. In this paper, we present first comparison results for these imager aerosol/cloud optical extinction coefficient profiles, with the ones derived from measurements performed by 3 solar occultation instruments (SAGE II, SAGE III, POAM III), one stellar occultation instrument (GOMOS) and one limb sounder (OSIRIS). The results indicate that the ACE imager profiles are of good quality in the upper troposphere/lower stratosphere, although the aerosol extinction for the visible channel at 525 nm contains a significant negative bias at higher altitudes, while the relative differences indicate that ACE profiles are almost always too high at 1020 nm. Both problems are probably related to ACE imager instrumental issues.

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Fast-Atom Bombardment Mass Spectrometry in Heterogeneous Atmospheric Chemistry

European Journal of Mass Spectrometry ◽

10.1255/ejms.481 ◽

2002 ◽

Vol 8 (2) ◽

pp. 131-138 ◽

Cited By ~ 1

Author(s):

G.B. Pronchev ◽

I.A. Korobeinikova ◽

A.N. Yermakov

Keyword(s):

Mass Spectrometry ◽

Atmospheric Aerosols ◽

Atmospheric Chemistry ◽

Fast Atom Bombardment ◽

Atmospheric Water ◽

Ferric Ions ◽

Fab Mass Spectrometry ◽

Essential Components ◽

The Given ◽

Heterogeneous Atmospheric Chemistry

The application of fast-atom bombardment (FAB) mass spectrometry to solving the problems of heterogeneous atmospheric chemistry is briefly reviewed. The method is useful in studying the state of surfaces and molecules adsorbed thereon and looks appropriate in investigations of the dynamics and mechanisms of chemical reactions occurring both on a surface and in a volume of moving particulate matter suspended in a gas. It was shown that composition of atmospheric aerosols and components dissolved in atmospheric water (clouds, fogs, mists etc.) can be determined by the FAB technique. The given method, as was found in our investigations, allows the discrimination of ferrous and ferric ions. Detection limits for concentrations of H2SO4 and Fe(II / III) ions as essential components of atmospheric water determined in model experiments are established at the level of 10−6 M.

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Global airborne microbial communities controlled by surrounding landscapes and wind conditions

Scientific Reports ◽

10.1038/s41598-019-51073-4 ◽

2019 ◽

Vol 9 (1) ◽

Cited By ~ 16

Author(s):

Romie Tignat-Perrier ◽

Aurélien Dommergue ◽

Alban Thollot ◽

Christoph Keuschnig ◽

Olivier Magand ◽

...

Keyword(s):

Particulate Matter ◽

High Altitude ◽

Microbial Communities ◽

Atmospheric Chemistry ◽

Sampling Site ◽

Temporal Stability ◽

Fungal Species ◽

The World ◽

Bacteria And Fungi ◽

Over Time

Abstract The atmosphere is an important route for transporting and disseminating microorganisms over short and long distances. Understanding how microorganisms are distributed in the atmosphere is critical due to their role in public health, meteorology and atmospheric chemistry. In order to determine the dominant processes that structure airborne microbial communities, we investigated the diversity and abundance of both bacteria and fungi from the PM10 particle size (particulate matter of 10 micrometers or less in diameter) as well as particulate matter chemistry and local meteorological characteristics over time at nine different meteorological stations around the world. The bacterial genera Bacillus and Sphingomonas as well as the fungal species Pseudotaeniolina globaosa and Cladophialophora proteae were the most abundant taxa of the dataset, although their relative abundances varied greatly based on sampling site. Bacterial and fungal concentration was the highest at the high-altitude and semi-arid plateau of Namco (China; 3.56 × 106 ± 3.01 × 106 cells/m3) and at the high-altitude and vegetated mountain peak Storm-Peak (Colorado, USA; 8.78 × 104 ± 6.49 × 104 cells/m3), respectively. Surrounding ecosystems, especially within a 50 km perimeter of our sampling stations, were the main contributors to the composition of airborne microbial communities. Temporal stability in the composition of airborne microbial communities was mainly explained by the diversity and evenness of the surrounding landscapes and the wind direction variability over time. Airborne microbial communities appear to be the result of large inputs from nearby sources with possible low and diluted inputs from distant sources.

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