Abstract

Global dust storms on Mars are rare1,2 but can affect the Martian atmosphere for several months. They can cause changes in atmospheric dynamics and inflation of the atmosphere3, primarily owing to solar heating of the dust3. In turn, changes in atmospheric dynamics can affect the distribution of atmospheric water vapour, with potential implications for the atmospheric photochemistry and climate on Mars4. Recent observations of the water vapour abundance in the Martian atmosphere during dust storm conditions revealed a high-altitude increase in atmospheric water vapour that was more pronounced at high northern latitudes5,6, as well as a decrease in the water column at low latitudes7,8. Here we present concurrent, high-resolution measurements of dust, water and semiheavy water (HDO) at the onset of a global dust storm, obtained by the NOMAD and ACS instruments onboard the ExoMars Trace Gas Orbiter. We report the vertical distribution of the HDO/H2O ratio (D/H) from the planetary boundary layer up to an altitude of 80 kilometres. Our findings suggest that before the onset of the dust storm, HDO abundances were reduced to levels below detectability at altitudes above 40 kilometres. This decrease in HDO coincided with the presence of water-ice clouds. During the storm, an increase in the abundance of H2O and HDO was observed at altitudes between 40 and 80 kilometres. We propose that these increased abundances may be the result of warmer temperatures during the dust storm causing stronger atmospheric circulation and preventing ice cloud formation, which may confine water vapour to lower altitudes through gravitational fall and subsequent sublimation of ice crystals3. The observed changes in H2O and HDO abundance occurred within a few days during the development of the dust storm, suggesting a fast impact of dust storms on the Martian atmosphere.

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Data availability

The datasets generated by the NOMAD and ACS instruments and analysed in this study will be available in the ESA PSA repository, https://archives.esac.esa.int/psa, after the proprietary period. The datasets used directly in this study, including the data used for the figures, are available from the corresponding author upon reasonable request.

Code availability

The codes used to calculate the dust/aerosol optical depths shown in Fig. 1 are available upon request from the corresponding author. The code used to inverse the NOMAD and ACS spectra and derive density profiles has been favourably compared to the PSG tool, which can be accessed at https://psg.gsfc.nasa.gov/ and which is part of this study. A version of the retrieval code is available at https://psg.gsfc.nasa.gov/helpatm.php#retrieval.

Additional information

Publisher’s note: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Change history

  • 17 April 2019

    The surname of author Cathy Quantin-Nataf was misspelled ‘Quantin-Nata’ , authors Ehouarn Millour and Roland Young were missing from the ACS Science Team list, and minor changes have been made to the author and affiliation lists; see accompanying Amendment. These errors have been corrected online.

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Acknowledgements

ExoMars is a space mission of the European Space Agency (ESA) and Roscosmos. The NOMAD experiment is led by the Royal Belgian Institute for Space Aeronomy (IASB-BIRA), assisted by Co-Principal Investigator teams from Spain (IAA-CSIC), Italy (INAF-IAPS) and the UK (Open University). This project acknowledges funding by the Belgian Science Policy Office (BELSPO), with financial and contractual coordination by the ESA Prodex Office (PEA 4000103401, 4000121493); by the Spanish MICINN through its Plan Nacional and by European funds under grants ESP2015-65064-C2-1-P and ESP2017-87143-R (MINECO/FEDER); by the UK Space Agency through grants ST/R005761/1, ST/P001262/1, ST/R001405/1, ST/S00145X/1, ST/R001367/1, ST/P001572/1 and ST/R001502/1; and the Italian Space Agency through grant 2018-2-HH.0. The IAA/CSIC team acknowledges financial support from the State Agency for Research of the Spanish MCIU through the ‘Center of Excellence Severo Ochoa’ award for the Instituto de Astrofísica de Andalucía (SEV-2017-0709). This work was supported by the Belgian Fonds de la Recherche Scientifique – FNRS under grant number 30442502 (ET_HOME). The ACS experiment is led by IKI, Space Research Institute in Moscow, assisted by LATMOS in France. The project acknowledges funding by Roscosmos and CNES. The science operations of ACS are funded by Roscosmos and ESA. IKI affiliates acknowledge funding under grant number 14.W03.31.0017 and contract number 0120.0 602993 (0028-2014-0004) of the Russian government. We are grateful to all ESA ESOC, ESAC and IKI Science Operations Center personnel, whose efforts made the success of TGO possible.

Reviewer information

Nature thanks Timothy McConnochie and the other anonymous reviewer(s) for their contribution to the peer review of this work.

Author information

Author notes

  1. A list of participants and their affiliations appears at the end of the paper.

Affiliations

  1. Royal Belgian Institute for Space Aeronomy (IASB-BIRA), Brussels, Belgium

    • Ann Carine Vandaele
    • , Frank Daerden
    • , Shohei Aoki
    • , Ian R. Thomas
    • , Justin T. Erwin
    • , Loïc Trompet
    • , David Bolsée
    • , Cédric Depiesse
    • , Arnaud Mahieux
    • , Lori Neary
    • , Eddy Neefs
    • , Bojan Ristic
    • , Séverine Robert
    • , Sébastien Viscardy
    • , Yannick Willame
    • , Valérie Wilquet
    • , Ann Carine Vandaele
    • , Shohei Aoki
    • , David Bolsée
    • , Frank Daerden
    • , Fabiana Da Pieve
    • , Cédric Depiesse
    • , Justin T. Erwin
    • , Didier Fussen
    • , Arnaud Mahieux
    • , Lori Neary
    • , Eddy Neefs
    • , Arianna Piccialli
    • , Séverine Robert
    • , Ian R. Thomas
    • , Loïc Trompet
    • , Sébastien Viscardy
    • , Valerie Wilquet
    • , Yannick Willame
    • , Ian R. Thomas
    •  & Valérie Wilquet
  2. Space Research Institute (IKI), Russian Academy of Sciences (RAS), Moscow, Russia

    • Oleg Korablev
    • , Anna A. Fedorova
    • , Alexander Trokhimovskiy
    • , Denis A. Belyaev
    • , Nikolay I. Ignatiev
    • , Mikhail Luginin
    • , Jean-Loup Bertaux
    • , Daria Betsis
    • , Alexey V. Grigoriev
    • , Igor Maslov
    • , Andrey Patrakeev
    • , Dmitry Patsaev
    • , Alexey Shakun
    • , Daniel Rodionov
    • , Anna A. Fedorova
    • , Nicolay I. Ignatiev
    • , Alexander Trokhimovskiy
    • , Konstantin Anufreychik
    • , Denis A. Belyaev
    • , Jean-Loup Bertaux
    • , Anna A. Fedorova
    • , Alexey V. Grigoriev
    • , Nikolay I. Ignatiev
    • , Igor Khatuntsev
    • , Nikita Kokonkov
    • , Oleg Korablev
    • , Ruslan Kuzmin
    • , Igor Maslov
    • , Mikhail Luginin
    • , Boris Moshkin
    • , Andrey Patrakeev
    • , Dmitry Patsaev
    • , Daniel Rodionov
    • , Alexey Shakun
    • , Alexander Trokhimovsky
    • , Ludmila Zasova
    •  & Lev Zelenyi
  3. Istituto di Astrofisica e Planetologia Spaziali (IAPS/INAF), Rome, Italy

    • Francesca Altieri
    • , Marco Giuranna
    • , Giancarlo Bellucci
    • , Giancarlo Bellucci
    • , Francesca Altieri
    • , Giacomo Carrozzo
    • , Emiliano D’Aversa
    • , Giuseppe Etiope
    • , Anna Geminale
    • , Marco Giuranna
    • , Fabrizio Oliva
    • , Paulina Wolkenberg
    • , Francesca Altieri
    •  & Davide Grassi
  4. Instituto de Astrofìsica de Andalucia (IAA), Consejo Superior de Investigaciones Científicas (CSIC), Granada, Spain

    • Miguel López-Valverde
    • , Bernd Funke
    • , Maia Garcia-Comas
    • , Francisco Gonzalez-Galindo
    • , Manuel López-Puertas
    • , Jose-Juan López-Moreno
    • , Jose-Juan López-Moreno
    • , Bernd Funke
    • , Maia Garcia-Comas
    • , Francisco Gonzalez-Galindo
    • , Manuel López-Puertas
    • , Miguel López-Valverde
    •  & Miguel López-Valverde
  5. NASA Goddard Space Flight Center, Greenbelt, MD, USA

    • Geronimo Villanueva
    • , Giuliano Liuzzi
    • , Michael D. Smith
    • , Michael J. Mumma
    • , Matteo Crismani
    • , Giuliano Liuzzi
    • , Michael J. Mumma
    • , Robert E. Novak
    • , Michael D. Smith
    •  & Geronimo Villanueva
  6. Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), UVSQ Université Paris-Saclay, Sorbonne Université, CNRS, Paris, France

    • Franck Montmessin
    • , Kevin S. Olsen
    • , Lucio Baggio
    • , Jean-Loup Bertaux
    • , Franck Lefèvre
    • , Franck Lefèvre
    • , Lucio Baggio
    • , Jean-Loup Bertaux
    • , Gaétan Lacombe
    • , Franck Lefèvre
    • , Anni Määttänen
    • , Emmanuel Marcq
    • , Franck Montmessin
    •  & Kevin S. Olsen
  7. Department of Physics, Oxford University, Oxford, UK

    • Juan Alday
    • , Colin F. Wilson
    • , Juan Alday
    •  & Colin F. Wilson
  8. Space Science Institute, Boulder, CO, USA

    • R. Todd Clancy
    • , Michael J. Wolff
    • , R. Todd Clancy
    •  & Michael J. Wolff
  9. Department of Geography, University of Winnipeg, Winnipeg, Manitoba, Canada

    • Edward Cloutis
    •  & Edward Cloutis
  10. Laboratory for Planetary and Atmospheric Physics (LPAP), University of Liège, Liège, Belgium

    • Jean-Claude Gérard
    • , Jean-Claude Gérard
    • , Leo Gkouvelis
    • , Benoît Hubert
    •  & Birgit Ritter
  11. Main Astronomical Observatory (MAO), National Academy of Sciences of Ukraine, Kiev, Ukraine

    • Yuriy S. Ivanov
  12. Institute of Geophysics, Polish Academy of Sciences, Warsaw, Poland

    • Jacek Kaminski
    •  & Jacek Kaminski
  13. Royal Observatory of Belgium, Brussels, Belgium

    • Ozgur Karatekin
    • , Ozgur Karatekin
    •  & Birgit Ritter
  14. School of Physical Sciences, The Open University, Milton Keynes, UK

    • Stephen Lewis
    • , Jon Mason
    • , Manish R. Patel
    • , Manish R. Patel
    • , James Holmes
    • , Stephen Lewis
    • , Jon Mason
    •  & Manish R. Patel
  15. Geosciences Paris Sud (GEOPS), Université Paris Sud, Orsay, France

    • Frédéric Schmidt
    •  & Frédéric Schmidt
  16. School of Earth Sciences, University of Bristol, Bristol, UK

    • Nicholas A. Teanby
    •  & Nicholas A. Teanby
  17. Centre for Research in Earth and Space Science, York University, Toronto, Ontario, Canada

    • James Whiteway
    •  & James Whiteway
  18. Laboratoire de Météorologie Dynamique (LMD), CNRS Jussieu, Paris, France

    • François Forget
    • , François Forget
    • , Sandrine Guerlet
    • , Ehouarn Millour
    •  & Roland Young
  19. European Space Research and Technology Centre (ESTEC), ESA, Noordwijk, The Netherlands

    • Håkan Svedhem
    •  & Jorge L. Vago
  20. Instituto Universitario de Microgravedad, Universidad Politécnica de Madrid (IDR-UPM), Madrid, Spain

    • Gustavo Alonso-Rodrigo
  21. Université Libre de Bruxelles, Brussels, Belgium

    • Sophie Bauduin
    •  & Jean Vander Auwera
  22. Istituto Nazionale di Geofisica e Vulcanologia, Rome, Italy

    • Giuseppe Etiope
  23. Faculty of Environmental Science and Engineering, Babes-Bolyai University, Cluj-Napoca, Romania

    • Giuseppe Etiope
  24. Tohoku University, Sendai, Japan

    • Yasumasa Kasaba
    • , Hiromu Nakagawa
    •  & Yasumasa Kasaba
  25. Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA

    • David Kass
    •  & Armin Kleinböhl
  26. Agenzia Spaziale Italiana (ASI), Rome, Italy

    • Orietta Lanciano
    •  & Giuseppe Sindoni
  27. Advanced Mechanical and Optical Systems (AMOS), Liège, Belgium

    • Etienne Renotte
  28. Laboratory for Atmospheric and Space Physics (LASP), Boulder, CO, USA

    • Nick Schneider
    •  & Ed Thiemann
  29. Lunar and Planetary Laboratory (LPL), University of Arizona, Tucson, AZ, USA

    • Roger Yelle
  30. Deutsches Zentrum für Luft- und Raumfahrt (DLR), Institute of Planetary Research, Berlin, Germany

    • Gabriele Arnold
  31. Moscow University, Moscow, Russia

    • Natalia Duxbury
  32. Laboratoire d’études spatiales et d’instrumentation en astrophysique (LESIA), Observatoire de Paris-Meudon, Paris, France

    • Thierry Fouchet
    •  & Emmanuel Lellouch
  33. Max Planck Institute, Göttingen, Germany

    • Paul Hartogh
    •  & Alexander Medvedev
  34. Catholic University of America, Washington, DC, USA

    • Vladimir Krasnopolsky
  35. School of Fundamental and Applied Physics, Moscow Institute of Physics and Technology (MIPT), Moscow, Russia

    • Vladimir Krasnopolsky
    •  & Alexander Rodin
  36. Vernadsky Institute, Russian Academy of Sciences (RAS), Moscow, Russia

    • Ruslan Kuzmin
  37. Luleå University of Technology, Luleå, Sweden

    • Javier Martin-Torres
  38. Instituto Andaluz de Ciencias de la Tierra, Universidad de Granada, Granada, Spain

    • Javier Martin-Torres
  39. Laboratoire de Géologie de Lyon, Université Claude Bernard, Lyon, France

    • Cathy Quantin-Nataf
  40. Institute of Astronomy, Russian Academy of Sciences (RAS), Moscow, Russia

    • Valery Shematovich
  41. University of Bern, Bern, Switzerland

    • Nicolas Thomas
  42. Universidad Complutense de Madrid, Madrid, Spain

    • Luis Vazquez
  43. Institut d’Astrophysique Spatiale, Université Paris Sud, Orsay, France

    • Matthieu Vincendon
  44. Centro de Astrobiología, Instituto Nacional de Técnica Aeroespacial (CSIC/INTA), Madrid, Spain

    • Maria Paz Zorzano

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Consortia

  1. NOMAD Science Team

  1. ACS Science Team

Contributions

A.C.V. and O. Korablev conceived the study, collected inputs and wrote the paper. S.A., G.V. and G.L. retrieved trace gas abundances, including those of H2O and HDO, from the NOMAD instrument. I.R.T. analysed the SO solar occultation data. L.T. provided transmittances from the NOMAD SO v0.3a. J.T.E. and S.R. provided and analysed the data used as input for the retrieval method and initial global circulation model (GCM) fields. F.D. and L.N. provided the GCM fields. S.V., F.G.-G., F.L., S.L. and J.K. provided the GCM background and discussion. F.A., O. Karatekin and V.W. coordinated the dust observations between the infrared and ultraviolet regions, and nadir and occultation. M.L.-V., J.-C.G, M.G.-C., M.L.-P. and B.F. analysed the NOMAD limb data. M.L.-P. provided the dust profiles from the NOMAD infrared channel. M.D.S., R.T.C. and M.J.W. provided contextual information from the Themis/Mars Orbiter instrument. M.G. provided contextual information from PFS/Mars Express. M.J.M. provided support for the spectroscopic parameters selection. F.S. and N.A.T. provided alternative methods to derive trace gases from the NOMAD infrared channel. J.W. and E.C. provided support for the selection of the surface properties. A.M. gave support for the calibration of the infrared channels. C.D., D. Bolsée and Y.W. were involved in the UVIS calibration and data pipeline. B.R. and E.N. designed the NOMAD observations, helped by J.M. for the UVIS channel. A.A.F. calibrated the ACS NIR data and analysed the water profiles assisted by F.M., A.T., D. Betsis and J.-L.B. CO2 data were analysed by D.A.B. The datasets for ACS NIR were prepared by A.T. and A.P., and N.I.I., A.S. and I.M. prepared the TIRVIM dataset. A.T. and A.V.G. designed the ACS observations. M.L. and D.P. analysed the TIRVIM occultation profiles. K.S.O., J.A. and L.B. provided support for the water retrieval. Y.S.I. helped in the MIR calibration. M.R.P., G.B. and J.-J.L.-M. provided support in the selection of the NOMAD observations based on scientific interest. F.F., C.F.W., D.R., J.L.V. and H.S. coordinated the observations of the various instruments on TGO. All authors assisted A.C.V. and O. Korablev with the preparation of the manuscript.

Competing interests

The authors declare no competing interests.

Corresponding author

Correspondence to Ann Carine Vandaele.

Extended data figures and tables

  1. Extended Data Fig. 1 Continuum optical depth versus latitude and solar longitude.

    The colour denotes the lowest altitude at which the optical depth is less than 1.0, that is, the lowest altitude where sunlight can still penetrate the atmosphere easily. There is a strong latitudinal dependence, with northern and southern high latitudes being relatively clear until the line of sight drops below 10–15 km (blue and dark blue)—except during the Ls = 200°–240° period, where the GDS appears to have raised this altitude to 20–25 km (light blue and cyan).

  2. Extended Data Fig. 2 Impact of the dust storm on NOMAD LNO nadir observations.

    a, b, The calibrated radiance at 2.3 μm is shown for two orbits, before (a) and during (b) the dust event, as a function of the latitude. Red lines show the results of a radiative-transfer model. The dust opacity before the GDS is τ = 0.46 at 3 μm, whereas during the event there is an increase by at least a factor of 10 (τ = 4.6). The 1σ error of the data is 8.2 × 10−5 W m−2 sr−1 cm. c, Surface albedo. Black, albedo at 2.33 μm from the OMEGA/Mars Express instrument (corresponding to NOMAD order 190); red, bond albedo from the TES/Mars Global Surveyor instrument, scaled to the OMEGA one.

  3. Extended Data Fig. 3 Atmospheric transmittances measured by NOMAD during the storm.

    Data obtained at Ls = 196.64°, latitude 51° N and longitude 148° E, showing HDO absorption features (arrows) appearing at tangent heights of up to 50 km; most of the other absorption features originate from CO2. The transmittances have been normalized by the continuum defined by a fifth-order polynomial applied to eliminate aerosol extinction and instrument effects. The transmittances are plotted with an interval of 0.015 to avoid overlapping. Source data

  4. Extended Data Fig. 4 Example of NOMAD water-retrieval results.

    Top, transmittance measured at a tangent height of 22.2 km (black), best fit (blue) and different simulations with 1 p.p.m. (cyan) and 100 p.p.m. (green) water content. The insets show zooms on two absorption lines of water. Bottom, residuals between the observation and the best fit. The transmittance errors were calculated from the 1σ noise value.

  5. Extended Data Fig. 5 Example of ACS NIR water-retrieval results.

    Top, transmittance measured at a tangent height of 34.1 km (black), best fit (blue) and different simulations with no water (cyan), 1 p.p.m. (red) and 50 p.p.m. (green) water content. The insets show zooms on several absorption lines of water. Bottom, residuals between the observation and the best fit. The transmittance errors were calculated from the 1σ noise value.

  6. Extended Data Fig. 6 Extinction of water ice measured by NOMAD.

    Results shown as a function of particle size (retrieved effective radius, reff; top) and slant optical depth (in units of km−1; bottom). Data obtained for the solar occultation before the dust storm, on 7 May between 05:40 and 05:46 utc (local time 18:00), which covers the latitude range 44° N to 57° N and the longitude range −122.6° E to −121.4° E. Source data

  7. Extended Data Fig. 7 Independent retrieval of dust and water ice from the TIRVIM dataset.

    Data obtained for a typical southern-hemisphere occultation (20 June 2018; latitude (Lat) 81° N; longitude (Lon) −66° E; egress). Shown is a selection of transmission profiles at five wavelengths (left), the corresponding slant opacities (top centre) and extinction profiles (top right), the retrieved effective radius reff (in micrometres; bottom centre) and the aerosol number density (in cm−3; bottom right). The occultation measurement was performed at orbit 2556 (local time 21:25) and covers the latitude range 81° N to 82° N and the longitude range −67° E to −60° E. The observation corresponds to the ACS MIR H2O and HDO profiles shown in Fig. 3 (yellow curves). The water ice and dust are well distinguished using the 3-µm water-ice absorption band (wavenumber 3,263 cm−1 in the figure). In this case the water-ice cloud is detected at 25–30 km. All errors shown are 1σ.

  8. Extended Data Table 1 Overview of NOMAD and ACS observations of H2O and HDO used in this study

Source data

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DOI

https://doi.org/10.1038/s41586-019-1097-3

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