Ammonium nitrate particles formed in upper troposphere from ground ammonia sources during Asian monsoons


The rise of ammonia emissions in Asia is predicted to increase radiative cooling and air pollution by forming ammonium nitrate particles in the lower troposphere. There is, however, a severe lack of knowledge about ammonia and ammoniated aerosol particles in the upper troposphere and their possible effects on the formation of clouds. Here we employ satellite observations and high-altitude aircraft measurements, combined with atmospheric trajectory simulations and cloud-chamber experiments, to demonstrate the presence of ammonium nitrate particles and also track the source of the ammonia that forms into the particles. We found that during the Asian monsoon period, solid ammonium nitrate particles are surprisingly ubiquitous in the upper troposphere from the Eastern Mediterranean to the Western Pacific—even as early as in 1997. We show that this ammonium nitrate aerosol layer is fed by convection that transports large amounts of ammonia from surface sources into the upper troposphere. Impurities of ammonium sulfate allow the crystallization of ammonium nitrate even in the conditions, such as a high relative humidity, that prevail in the upper troposphere. Solid ammonium nitrate particles in the upper troposphere play a hitherto neglected role in ice cloud formation and aerosol indirect radiative forcing.

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Fig. 1: AN observed by CRISTA in the UT in 1997.
Fig. 2: Time series of AN and NH3 in the AMA.
Fig. 3: Airborne limb-imaging observations of AN and NH3 in the UT above India during the 2017 Asian monsoon season.
Fig. 4: Airborne in situ aerosol observations in the Asian monsoon UT on 31 July 2017.

Data availability

The data sets generated and analysed during the current study are available from the corresponding author upon request. Additionally, the CRISTA data set of AN is publicly available at MIPAS and GLORIA data for NH3 and AN as well as trajectory information and AIDA spectra can be downloaded from the KITopen archive at IASI data on NH3 are available at


  1. 1.

    Dentener, F. J. & Crutzen, P. J. A three-dimensional model of the global ammonia cycle. J. Atmos. Chem. 19, 331–369 (1994).

    Google Scholar 

  2. 2.

    Behera, S. N., Sharma, M., Aneja, V. P. & Balasubramanian, R. Ammonia in the atmosphere: a review on emission sources, atmospheric chemistry and deposition on terrestrial bodies. Environ. Sci. Pollut. Res. 20, 8092–8131 (2013).

    Google Scholar 

  3. 3.

    Bouwman, A. et al. A global high-resolution emission inventory for ammonia. Glob. Biogeochem. Cycles 11, 561–587 (1997).

    Google Scholar 

  4. 4.

    Erisman, J. W., Sutton, M. A., Galloway, J., Klimont, Z. & Winiwarter, W. How a century of ammonia synthesis changed the world. Nat. Geosci. 1, 636–639 (2008).

    Google Scholar 

  5. 5.

    Warner, J. X. et al. Increased atmospheric ammonia over the world’s major agricultural areas detected from space. Geophys. Res. Lett. 44, 2875–2884 (2017).

    Google Scholar 

  6. 6.

    Xu, R. T. et al. Half-century ammonia emissions from agricultural systems in southern Asia: magnitude, spatiotemporal patterns, and implications for human health. Geohealth 2, 40–53 (2018).

    Google Scholar 

  7. 7.

    Hauglustaine, D. A., Balkanski, Y. & Schulz, M. A global model simulation of present and future nitrate aerosols and their direct radiative forcing of climate. Atmos. Chem. Phys. 14, 11031–11063 (2014).

    Google Scholar 

  8. 8.

    IPCC Climate Change 2013: The Physical Science Basis (eds Stocker, T. F. et al.) (Cambridge Univ. Press, 2013).

  9. 9.

    Kirkby, J. et al. Role of sulphuric acid, ammonia and galactic cosmic rays in atmospheric aerosol nucleation. Nature 476, 429–433 (2011).

    Google Scholar 

  10. 10.

    Kürten, A. et al. Experimental particle formation rates spanning tropospheric sulfuric acid and ammonia abundances, ion production rates, and temperatures. J. Geophys. Res. 121, 12377–12400 (2016).

    Google Scholar 

  11. 11.

    Abbatt, J. P. D. et al. Solid ammonium sulfate aerosols as ice nuclei: a pathway for cirrus cloud formation. Science 313, 1770–1773 (2006).

    Google Scholar 

  12. 12.

    Cziczo, D. J. & Abbatt, J. P. D. Infrared observations of the response of NaCl, MgCl2, NH4HSO4, and NH4NO3 aerosols to changes in relative humidity from 298 to 238 K. J. Phys. Chem. A 104, 2038–2047 (2000).

    Google Scholar 

  13. 13.

    Cziczo, D. J. & Abbatt, J. P. D. Ice nucleation in NH4HSO4, NH4NO3, and H2SO4 aqueous particles: implications for cirrus cloud formation. Geophys. Res. Lett. 28, 963–966 (2001).

    Google Scholar 

  14. 14.

    Höpfner, M. et al. First detection of ammonia (NH3) in the Asian summer monsoon upper troposphere. Atmos. Chem. Phys. 16, 14357–14369 (2016).

    Google Scholar 

  15. 15.

    Ploeger, F. et al. A potential vorticity-based determination of the transport barrier in the Asian summer monsoon anticyclone. Atmos. Chem. Phys. 15, 13145–13159 (2015).

    Google Scholar 

  16. 16.

    Park, M., Randel, W. J., Gettelman, A., Massie, S. T. & Jiang, J. H. Transport above the Asian summer monsoon anticyclone inferred from Aura Microwave Limb Sounder tracers. J. Geophys. Res. 112, D16309 (2007).

    Google Scholar 

  17. 17.

    Park, M. et al. Chemical isolation in the Asian monsoon anticyclone observed in Atmospheric Chemistry Experiment (ACE-FTS) data. Atmos. Chem. Phys. 8, 757–764 (2008).

    Google Scholar 

  18. 18.

    Randel, W. J. et al. Asian monsoon transport of pollution to the stratosphere. Science 328, 611–613 (2010).

    Google Scholar 

  19. 19.

    Ungermann, J. et al. Observations of PAN and its confinement in the Asian summer monsoon anticyclone in high spatial resolution. Atmos. Chem. Phys. 16, 8389–8403 (2016).

    Google Scholar 

  20. 20.

    Santee, M. L. et al. A comprehensive overview of the climatological composition of the Asian summer monsoon anticyclone based on 10 years of Aura microwave limb sounder measurements. J. Geophys. Res. 122, 5491–5514 (2017).

    Google Scholar 

  21. 21.

    Lelieveld, J. et al. The South Asian monsoon: pollution pump and purifier. Science 361, 270–273 (2018).

    Google Scholar 

  22. 22.

    Ploeger, F., Konopka, P., Walker, K. & Riese, M. Quantifying pollution transport from the Asian monsoon anticyclone into the lower stratosphere. Atmos. Chem. Phys. 17, 7055–7066 (2017).

    Google Scholar 

  23. 23.

    Yu, P. et al. Efficient transport of tropospheric aerosol into the stratosphere via the Asian summer monsoon anticyclone. Proc. Natl Acad. Sci. USA 114, 6972–6977 (2017).

    Google Scholar 

  24. 24.

    Vernier, J.-P., Tomason, L. W. & Kar, J. CALIPSO detection of an Asian tropopause aerosol layer. Geophys. Res. Lett. 38, L07804 (2011).

    Google Scholar 

  25. 25.

    Thomason, L. W. & Vernier, J.-P. Improved SAGE II cloud/aerosol categorization and observations of the Asian tropopause aerosol layer: 1989–2005. Atmos. Chem. Phys. 13, 4605–4616 (2013).

    Google Scholar 

  26. 26.

    Vernier, J. P. et al. Increase in upper tropospheric and lower stratospheric aerosol levels and its potential connection with Asian pollution. J. Geophys. Res. 120, 1608–1619 (2015).

    Google Scholar 

  27. 27.

    Vernier, J.-P. et al. BATAL: the balloon measurement campaigns of the Asian tropopause aerosol layer. Bull. Am. Meteorol. Soc. 99, 955–973 (2018).

    Google Scholar 

  28. 28.

    Fadnavis, S. et al. Transport of aerosols into the UTLS and their impact on the Asian monsoon region as seen in a global model simulation. Atmos. Chem. Phys. 13, 8771–8786 (2013).

    Google Scholar 

  29. 29.

    Neely, R. R. et al. The contribution of anthropogenic SO2 emissions to the Asian tropopause aerosol layer. J. Geophys. Res. 119, 1571–1579 (2014).

    Google Scholar 

  30. 30.

    Yu, P., Toon, O. B., Neely, R. R., Martinsson, B. G. & Brenninkmeijer, C. A. M. Composition and physical properties of the Asian tropopause aerosol layer and the North American tropospheric aerosol layer. Geophys. Res. Lett. 42, 2540–2546 (2015).

    Google Scholar 

  31. 31.

    Lau, W. K. M., Yuan, C. & Li, Z. Origin, maintenance and variability of the Asian Tropopause Aerosol Layer (ATAL): the roles of monsoon dynamics. Sci. Rep. 8, 3960 (2018).

    Google Scholar 

  32. 32.

    Gu, Y., Liao, H. & Bian, J. Summertime nitrate aerosol in the upper troposphere and lower stratosphere over the Tibetan Plateau and the South Asian summer monsoon region. Atmos. Chem. Phys. 16, 6641–6663 (2016).

    Google Scholar 

  33. 33.

    Schlenker, J. C. & Martin, S. T. Crystallization pathways of sulfate–nitrate–ammonium aerosol particles. J. Phys. Chem. A 109, 9980–9985 (2005).

    Google Scholar 

  34. 34.

    Vogel, B. et al. Lagrangian simulations of the transport of young air masses to the top of the Asian monsoon anticyclone and into the tropical pipe. Atmos. Chem. Phys. 19, 6007–6034 (2019).

    Google Scholar 

  35. 35.

    Friedl-Vallon, F. et al. Instrument concept of the imaging Fourier transform spectrometer GLORIA. Atmos. Meas. Tech. 7, 3565–3577 (2014).

    Google Scholar 

  36. 36.

    Riese, M. et al. Gimballed limb observer for radiance imaging of the atmosphere (GLORIA) scientific objectives. Atmos. Meas. Tech. 7, 1915–1928 (2014).

    Google Scholar 

  37. 37.

    Cai, Y., Montague, D. C., Mooiweer-Bryan, W. & Deshler, T. Performance characteristics of the ultra high sensitivity aerosol spectrometer for particles between 55 and 800 nm: laboratory and field studies. J. Aerosol Sci. 39, 759–769 (2008).

    Google Scholar 

  38. 38.

    Weigel, R. et al. In situ observations of new particle formation in the tropical upper troposphere: the role of clouds and the nucleation mechanism. Atmos. Chem. Phys. 11, 9983–10010 (2011).

    Google Scholar 

  39. 39.

    Drewnick, F. et al. A new time-of-flight aerosol mass spectrometer (TOF-AMS)—instrument description and first field deployment. Aerosol Sci. Technol. 39, 637–658 (2005).

    Google Scholar 

  40. 40.

    Allan, J. D. et al. A generalised method for the extraction of chemically resolved mass spectra from aerodyne aerosol mass spectrometer data. J. Aerosol Sci. 35, 909–922 (2004).

    Google Scholar 

  41. 41.

    Schulz, C. et al. Aircraft-based observations of isoprene-epoxydiol-derived secondary organic aerosol (IEPOX-SOA) in the tropical upper troposphere over the Amazon region. Atmos. Chem. Phys. 18, 14979–15001 (2018).

    Google Scholar 

  42. 42.

    Van Damme, M. et al. Version 2 of the IASI NH3 neural network retrieval algorithm: near-real-time and reanalysed datasets. Atmos. Meas. Tech. 10, 4905–4914 (2017).

    Google Scholar 

  43. 43.

    Clarisse, L., Clerbaux, C., Dentener, F., Hurtmans, D. & Coheur, P.-F. Global ammonia distribution derived from infrared satellite observations. Nat. Geosci. 2, 479–483 (2009).

    Google Scholar 

  44. 44.

    van Damme, M. et al. Industrial and agricultural ammonia point sources exposed. Nature 564, 99–103 (2018).

    Google Scholar 

  45. 45.

    Metzger, S., Dentener, F., Krol, M., Jeuken, A. & Lelieveld, J. Gas/aerosol partitioning 2. Global modeling results. J. Geophys. Res. 107, 4313 (2002).

    Google Scholar 

  46. 46.

    Hoog, I., Mitra, S. K., Diehl, K. & Borrmann, S. Laboratory studies about the interaction of ammonia with ice crystals at temperatures between 0 and −20 °C. J. Atmos. Chem. 57, 73–84 (2007).

    Google Scholar 

  47. 47.

    Jost, A., Szakáll, M., Diehl, K., Mitra, S. K. & Borrmann, S. Chemistry of riming: the retention of organic and inorganic atmospheric trace constituents. Atmos. Chem. Phys. 17, 9717–9732 (2017).

    Google Scholar 

  48. 48.

    Ge, C., Zhu, C., Francisco, J. S., Zeng, X. C. & Wang, J. A molecular perspective for global modeling of upper atmospheric NH3 from freezing clouds. Proc. Natl Acad. Sci. USA 115, 6147–6152 (2018).

    Google Scholar 

  49. 49.

    Möhler, O. et al. Experimental investigation of homogeneous freezing of sulphuric acid particles in the aerosol chamber AIDA. Atmos. Chem. Phys. 3, 211–223 (2003).

    Google Scholar 

  50. 50.

    Fahey, D. W. et al. The AquaVIT-1 intercomparison of atmospheric water vapor measurement techniques. Atmos. Meas. Tech. 7, 3177–3213 (2014).

    Google Scholar 

  51. 51.

    Wagner, R., Benz, S., Möhler, O., Saathoff, H. & Schurath, U. Probing ice clouds by broadband mid-infrared extinction spectroscopy: case studies from ice nucleation experiments in the AIDA aerosol and cloud chamber. Atmos. Chem. Phys. 6, 4775–4800 (2006).

    Google Scholar 

  52. 52.

    Schnaiter, M. et al. Influence of particle size and shape on the backscattering linear depolarisation ratio of small ice crystals—cloud chamber measurements in the context of contrail and cirrus microphysics. Atmos. Chem. Phys. 12, 10465–10484 (2012).

    Google Scholar 

  53. 53.

    Wagner, R. et al. A review of optical measurements at the aerosol and cloud chamber AIDA. J. Quant. Spectrosc. Radiat. Transf. 110, 930–949 (2009).

    Google Scholar 

  54. 54.

    Offermann, D. et al. Cryogenic infrared spectrometers and telescopes for the atmosphere (CRISTA) experiment and middle atmosphere variability. J. Geophys. Res. 104, 16311–16325 (1999).

    Google Scholar 

  55. 55.

    Riese, M. et al. Cryogenic infrared spectrometers and telescopes for the atmosphere (CRISTA) data processing and atmospheric temperature and trace gas retrieval. J. Geophys. Res. 104, 16349–16367 (1999).

    Google Scholar 

  56. 56.

    Grossmann, K. U. et al. The CRISTA-2 mission. J. Geophys. Res. 107, 8173 (2002).

    Google Scholar 

  57. 57.

    Fischer, H. et al. MIPAS: an instrument for atmospheric and climate research. Atmos. Chem. Phys. 8, 2151–2188 (2008).

    Google Scholar 

  58. 58.

    Kleinert, A. et al. Level 0 to 1 processing of the imaging Fourier transform spectrometer GLORIA: generation of radiometrically and spectrally calibrated spectra. Atmos. Meas. Tech. 7, 4167–4184 (2014).

    Google Scholar 

  59. 59.

    Toon, O. B., Tolbert, M. A., Middlebrook, A. M. & Jordan, J. Infrared optical constants of H2O, ice, amorphous nitric acid solutions, and nitric acid hydrates. J. Geophys. Res. 99, 25631–25654 (1994).

    Google Scholar 

  60. 60.

    Koch, T. G., Holmes, N. S., Roddis, T. B. & Sodeau, J. R. Low-temperature reflection/absorption IR study of thin films of nitric acid hydrates and ammonium nitrate adsorbed on gold foil. J. Chem. Soc. Faraday Trans. 92, 4787 (1996).

    Google Scholar 

  61. 61.

    Biermann, U. M. Gefrier- und FTIR-Experimente zur Nukleation und Lebensdauer stratosphärischer Wolken. PhD thesis, Universität Bielefeld (1998).

  62. 62.

    Spang, R. & Remedios, J. J. Observations of a distinctive infra-red spectral feature in the atmospheric spectra of polar stratospheric clouds measured by the CRISTA instrument. Geophys. Res. Lett. 30, 1875 (2003).

    Google Scholar 

  63. 63.

    Höpfner, M. et al. Spectroscopic evidence for NAT, STS, and ice in MIPAS infrared limb emission measurements of polar stratospheric clouds. Atmos. Chem. Phys. 6, 1201–1219 (2006).

    Google Scholar 

  64. 64.

    Woiwode, W. et al. Spectroscopic evidence of large aspherical β-NAT particles involved in denitrification in the December 2011 Arctic stratosphere. Atmos. Chem. Phys. 16, 9505–9532 (2016).

    Google Scholar 

  65. 65.

    Théorêt, A. & Sandorfy, C. Infrared spectra and crystalline phase transitions of ammonium nitrate. Can. J. Chem. 42, 57–62 (1964).

    Google Scholar 

  66. 66.

    Fernandes, J. R., Ganguly, S. & Rao, C. Infrared spectroscopic study of the phase transitions in CsNO3, RbNO3 and NH4NO3. Spectrochim. Acta A 35, 1013–1020 (1979).

    Google Scholar 

  67. 67.

    Allen, D. T., Palen, E. J., Haimov, M. I., Hering, S. V. & Young, J. R. Fourier transform infrared spectroscopy of aerosol collected in a low pressure impactor (LPI/FTIR): method development and field calibration. Aerosol Sci. Technol. 21, 325–342 (1994).

    Google Scholar 

  68. 68.

    Hopey, J. A., Fuller, K. A., Krishnaswamy, V., Bowdle, D. & Newchurch, M. J. Fourier transform infrared spectroscopy of size-segregated aerosol deposits on foil substrates. Appl. Opt. 47, 2266–2274 (2008).

    Google Scholar 

  69. 69.

    Earle, M. E., Pancescu, R. G., Cosic, B., Zasetsky, A. Y. & Sloan, J. J. Temperature-dependent complex indices of refraction for crystalline (NH4)2SO4. J. Phys. Chem. A 110, 13022–13028 (2006).

    Google Scholar 

  70. 70.

    Rosenoern, T., Schlenker, J. C. & Martin, S. T. Hygroscopic growth of multicomponent aerosol particles influenced by several cycles of relative humidity. J. Phys. Chem. A 112, 2378–2385 (2008).

    Google Scholar 

  71. 71.

    Laskina, O., Young, M. A., Kleiber, P. D. & Grassian, V. H. Infrared extinction spectra of mineral dust aerosol: Single components and complex mixtures. J. Geophys. Res. 117, D18210 (2012).

    Google Scholar 

  72. 72.

    Braban, C. F., Carroll, M. F., Styler, S. A. & Abbatt, J. P. D. Phase transitions of malonic and oxalic acid aerosols. J. Phys. Chem. A 107, 6594–6602 (2003).

    Google Scholar 

  73. 73.

    Miñambres, L., Sánchez, M. N., Castaño, F. & Basterretxea, F. J. Hygroscopic properties of internally mixed particles of ammonium sulfate and succinic acid studied by infrared spectroscopy. J. Phys. Chem. A 114, 6124–6130 (2010).

    Google Scholar 

  74. 74.

    Chasan, D. E. & Norwitz, G. Infrared determination of inorganic nitrates by the pellet technique; infrared determination of two inorganic nitrates in the presence of each other. Appl. Spectrosc. 24, 283–287 (1970).

    Google Scholar 

  75. 75.

    Harris, M. J., Salje, E. K. H. & Guttler, B. K. An infrared spectroscopic study of the internal modes of sodium nitrate: implications for the structural phase transition. J. Phys. Condens. Matter 2, 5517–5527 (1990).

    Google Scholar 

  76. 76.

    Ungermann, J. et al. CRISTA-NF measurements with unprecedented vertical resolution during the RECONCILE aircraft campaign. Atmos. Meas. Tech. 5, 1173–1191 (2012).

    Google Scholar 

  77. 77.

    Sutton, M. A., Erisman, J. W., Dentener, F. & Möller, D. Ammonia in the environment: from ancient times to the present. Environ. Pollut. 156, 583–604 (2008).

    Google Scholar 

  78. 78.

    von Bobrutzki, K. et al. Field inter-comparison of eleven atmospheric ammonia measurement techniques. Atmos. Meas. Tech. 3, 91–112 (2010).

    Google Scholar 

  79. 79.

    von Clarmann, T. et al. Retrieval of temperature, H2O, O3, HNO3, CH4, N2O, ClONO2 and ClO from MIPAS reduced resolution nominal mode limb emission measurements. Atmos. Meas. Tech. 2, 159–175 (2009).

    Google Scholar 

  80. 80.

    Tikhonov, A. On the solution of incorrectly stated problems and method of regularization. Dokl. Akad. Nauk. SSSR 151, 501–504 (1963).

    Google Scholar 

  81. 81.

    Woiwode, W. et al. Validation of first chemistry mode retrieval results from the new limb-imaging FTS GLORIA with correlative MIPAS-STR observations. Atmos. Meas. Tech. 8, 2509–2520 (2015).

    Google Scholar 

  82. 82.

    Johansson, S. et al. Airborne limb-imaging measurements of temperature, HNO3, O3, ClONO2, H2O and CFC-12 during the Arctic winter 2015/16: characterization, in situ validation and comparison to Aura/MLS. Atmos. Meas. Tech. 11, 4737–4756 (2018).

    Google Scholar 

  83. 83.

    Brands, M. et al. Characterization of a newly developed aircraft-based laser ablation aerosol mass spectrometer (ALABAMA) and first field deployment in urban pollution plumes over Paris during MEGAPOLI 2009. Aerosol Sci. Technol. 45, 46–64 (2011).

    Google Scholar 

  84. 84.

    Murphy, D. M. & Thomson, D. S. Laser ionization mass spectroscopy of single aerosol particles. Aerosol Sci. Technol. 22, 237–249 (1995).

    Google Scholar 

  85. 85.

    Cairo, F. et al. A comparison of light backscattering and particle size distribution measurements in tropical cirrus clouds. Atmos. Meas. Tech. 4, 557–570 (2011).

    Google Scholar 

  86. 86.

    Pisso, I. & Legras, B. Turbulent vertical diffusivity in the sub-tropical stratosphere. Atmos. Chem. Phys. 8, 697–707 (2008).

    Google Scholar 

  87. 87.

    Tissier, A.-S. & Legras, B. Convective sources of trajectories traversing the tropical tropopause layer. Atmos. Chem. Phys. 16, 3383–3398 (2016).

    Google Scholar 

  88. 88.

    Wohltmann, I. & Rex, M. The Lagrangian chemistry and transport model ATLAS: validation of advective transport and mixing. Geosci. Mod. Dev. 2, 153–173 (2009).

    Google Scholar 

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We acknowledge the Geophysica pilots and crew as well as the local support in Kathmandu. We are grateful to the instrument development and operation teams of GLORIA at KIT and Jülich, and of ERICA at MPI-C and IPA-JGU and to the technical team of AIDA at KIT. The work at KIT and Jülich was supported by the Helmholtz ATMO program. We thank the teams at ULB/LATMOS (Université Libre de Bruxelles/Laboratoire Atmosphères, Milieux, Observations Spatiales) for provision of the IASI NH3 data. The European Space Agency is acknowledged for MIPAS data provision. Meteorological analysis data were provided by the European Centre for Medium-Range Weather Forecasts. ERA5 trajectory computations were generated using Copernicus Climate Change Service Information. D. Offermann and his team are acknowledged for conducting the CRISTA observations in the AMA region. We thank M. L. Santee for helpful discussions on satellite data sets. Funding for the ERICA instrument development was provided by the European Research Council Advanced Grant to S. Borrmann (EXCATRO project, grant no. 321040). Part of this work was supported by the European Community’s Seventh Framework Programme (FP7/2007–2013) under grant agreement no. 603557, CEFIPRA5607-1, ANR-17-CE01-0015 and by the German “Bundesministerium für Bildung und Forschung” (BMBF) under the joint ROMIC-project SPITFIRE (01LG1205A). We also thank the Aeris data infrastructure for providing access to the MSG1 and Himawari data.

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M.H. conducted the analysis of MIPAS and GLORIA data, produced Figs. 24 and wrote the paper with all the authors contributing. J.U. conducted the analysis of the CRISTA data, helped with analysis of the GLORIA data and produced Fig. 1. A.D., S.M., A.M.B., O.A., A.H. and S. Borrmann performed and analysed the aircraft in situ measurements of ERICA. C.M. and R. Weigel prepared the analyses for Fig. 4a and O.A. for Fig. 4b. C.M. and R. Weigel conducted the measurements and data analyses for UHSAS and COPAS, respectively. R. Wagner, H.S., O.M. and T.L. conceived and performed the AIDA experiments and contributed to their interpretation. R.S. discovered the AN emission feature in the CRISTA data. M. Riese conceived the reanalysis of the CRISTA data with respect to signals of the ATAL. G.S. contributed to the analysis of the MIPAS data. B.L. and S. Bucci conducted the TRACZILLA trajectory calculations. F.C. performed the MAS aircraft observations and conducted their analysis. F.F.-V. conducted the GLORIA aircraft observations. S.J. analysed the trajectory data sets in combination with the IASI measurements. S.J. and L.K. helped with the analysis of the GLORIA data. P.P. contributed to the CRISTA and GLORIA data analysis. T.N. helped to perform the GLORIA observations. R.M. contributed to the interpretation of the observations. J.O. contributed to the interpretation of spectroscopic issues with AN and NH3. F.S. and M. Rex. defined the flight region, the general approach, general flight patterns and instrumentation of the aircraft campaign and organized it. I.W. developed the ATLAS model and provided the trajectory calculations from it, with contributions from M. Rex.

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Correspondence to Michael Höpfner.

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Höpfner, M., Ungermann, J., Borrmann, S. et al. Ammonium nitrate particles formed in upper troposphere from ground ammonia sources during Asian monsoons. Nat. Geosci. 12, 608–612 (2019).

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