Articles | Volume 18, issue 8
https://doi.org/10.5194/acp-18-5307-2018
© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/acp-18-5307-2018
© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
19 Apr 2018
Research article |
| 19 Apr 2018
| 19 Apr 2018
Concentration and variability of ice nuclei in the subtropical maritime boundary layer
Leibniz Institute for Tropospheric Research (TROPOS), Leipzig, Germany
Konrad Müller
Leibniz Institute for Tropospheric Research (TROPOS), Leipzig, Germany
Zoë L. Fleming
National Centre for Atmospheric Science (NCAS), Department of Chemistry, University of Leicester, Leicester, UK
Frank Stratmann
Leibniz Institute for Tropospheric Research (TROPOS), Leipzig, Germany
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Arctic sea-ice retreat, atmospheric new particle formation (NPF), and aerosol–cloud interaction may all be linked via a positive feedback mechanism. Understanding the sources of cloud condensation nuclei (CCN) is an important piece in the Arctic amplification puzzle. We show that Arctic newly formed particles do not have to grow beyond the Aitken mode to act as CCN. This is important, because NPF occurrence in the Arctic is expected to increase, making it a significant contributor to CCN budget.
André Welti, Ulrike Lohmann, and Zamin A. Kanji
Atmos. Chem. Phys., 19, 10901–10918, https://doi.org/10.5194/acp-19-10901-2019, https://doi.org/10.5194/acp-19-10901-2019, 2019
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The ice nucleation ability of singly immersed feldspar particles in suspended water droplets relevant for ice crystal formation under mixed-phase cloud conditions is presented. The effects of particle size, crystal structure, trace metal and mineralogical composition are discussed by testing up to five different diameters in the submicron range and nine different feldspar samples at conditions relevant for ice nucleation in mixed-phase clouds.
Paul J. DeMott, Ottmar Möhler, Daniel J. Cziczo, Naruki Hiranuma, Markus D. Petters, Sarah S. Petters, Franco Belosi, Heinz G. Bingemer, Sarah D. Brooks, Carsten Budke, Monika Burkert-Kohn, Kristen N. Collier, Anja Danielczok, Oliver Eppers, Laura Felgitsch, Sarvesh Garimella, Hinrich Grothe, Paul Herenz, Thomas C. J. Hill, Kristina Höhler, Zamin A. Kanji, Alexei Kiselev, Thomas Koop, Thomas B. Kristensen, Konstantin Krüger, Gourihar Kulkarni, Ezra J. T. Levin, Benjamin J. Murray, Alessia Nicosia, Daniel O'Sullivan, Andreas Peckhaus, Michael J. Polen, Hannah C. Price, Naama Reicher, Daniel A. Rothenberg, Yinon Rudich, Gianni Santachiara, Thea Schiebel, Jann Schrod, Teresa M. Seifried, Frank Stratmann, Ryan C. Sullivan, Kaitlyn J. Suski, Miklós Szakáll, Hans P. Taylor, Romy Ullrich, Jesus Vergara-Temprado, Robert Wagner, Thomas F. Whale, Daniel Weber, André Welti, Theodore W. Wilson, Martin J. Wolf, and Jake Zenker
Atmos. Meas. Tech., 11, 6231–6257, https://doi.org/10.5194/amt-11-6231-2018, https://doi.org/10.5194/amt-11-6231-2018, 2018
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The ability to measure ice nucleating particles is vital to quantifying their role in affecting clouds and precipitation. Methods for measuring droplet freezing were compared while co-sampling relevant particle types. Measurement correspondence was very good for ice nucleating particles of bacterial and natural soil origin, and somewhat more disparate for those of mineral origin. Results reflect recently improved capabilities and provide direction toward addressing remaining measurement issues.
Sarah Grawe, Stefanie Augustin-Bauditz, Hans-Christian Clemen, Martin Ebert, Stine Eriksen Hammer, Jasmin Lubitz, Naama Reicher, Yinon Rudich, Johannes Schneider, Robert Staacke, Frank Stratmann, André Welti, and Heike Wex
Atmos. Chem. Phys., 18, 13903–13923, https://doi.org/10.5194/acp-18-13903-2018, https://doi.org/10.5194/acp-18-13903-2018, 2018
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In this study, coal fly ash particles immersed in supercooled cloud droplets were analyzed concerning their freezing behavior. Additionally, physico-chemical particle properties (morphology, chemical composition, crystallography) were investigated. In combining both aspects, components that potentially contribute to the observed freezing behavior of the ash could be identified. Interactions at the particle-water interface, that depend on suspension time and influence freezing, are discussed.
Juliane L. Fry, Steven S. Brown, Ann M. Middlebrook, Peter M. Edwards, Pedro Campuzano-Jost, Douglas A. Day, José L. Jimenez, Hannah M. Allen, Thomas B. Ryerson, Ilana Pollack, Martin Graus, Carsten Warneke, Joost A. de Gouw, Charles A. Brock, Jessica Gilman, Brian M. Lerner, William P. Dubé, Jin Liao, and André Welti
Atmos. Chem. Phys., 18, 11663–11682, https://doi.org/10.5194/acp-18-11663-2018, https://doi.org/10.5194/acp-18-11663-2018, 2018
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This paper uses measurements made during research aircraft flights through power plant smokestack emissions plumes as a natural laboratory in the field experiment. We investigated a specific source of airborne particulate matter from the combination of human-produced NOx pollutant emissions (the smokestack plumes) with isoprene emitted by naturally by trees in the southeastern United States. These field-based yields appear to be higher than those typically measured in chamber studies.
Jin Liao, Charles A. Brock, Daniel M. Murphy, Donna T. Sueper, André Welti, and Ann M. Middlebrook
Atmos. Meas. Tech., 10, 3801–3820, https://doi.org/10.5194/amt-10-3801-2017, https://doi.org/10.5194/amt-10-3801-2017, 2017
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The Aerodyne aerosol mass spectrometer (AMS) has emerged as a widely used method for measuring the real-time, submicron, nonrefractory aerosol composition. A large uncertainty in accurate measurements with the AMS (the collection efficiency due to particle bounce) is evaluated in this paper using in situ measurements of particle light scattering. Current calculations of the collection efficiency reasonably predict this effect in acidic environments, resulting in more confidence for AMS results.
Monika Burkert-Kohn, Heike Wex, André Welti, Susan Hartmann, Sarah Grawe, Lisa Hellner, Paul Herenz, James D. Atkinson, Frank Stratmann, and Zamin A. Kanji
Atmos. Chem. Phys., 17, 11683–11705, https://doi.org/10.5194/acp-17-11683-2017, https://doi.org/10.5194/acp-17-11683-2017, 2017
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Several instruments can investigate properties of ice-nucleating particles (INPs), which are crucial to understanding ice cloud formation. We intercompare four online ice nucleation counters and reasonable agreement is found when the same ice nucleation mode is tested. A variable scaling factor was necessary to reconcile condensation freezing results with immersion freezing. Factors related to instrumental setup and aerosol generation are discussed to explain observed differences.
Luisa Ickes, André Welti, and Ulrike Lohmann
Atmos. Chem. Phys., 17, 1713–1739, https://doi.org/10.5194/acp-17-1713-2017, https://doi.org/10.5194/acp-17-1713-2017, 2017
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The goal of this study is to find a parameterization scheme for general circulation models to describe immersion freezing with the ability to shift and adjust the slope of the freezing curve compared to homogeneous freezing to match experimental data. We investigated how accurate different formulations of classical nucleation theory reproduce measured immersion freezing curves for different mineral dust types.
Yvonne Boose, André Welti, James Atkinson, Fabiola Ramelli, Anja Danielczok, Heinz G. Bingemer, Michael Plötze, Berko Sierau, Zamin A. Kanji, and Ulrike Lohmann
Atmos. Chem. Phys., 16, 15075–15095, https://doi.org/10.5194/acp-16-15075-2016, https://doi.org/10.5194/acp-16-15075-2016, 2016
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We compare the immersion freezing behavior of four airborne to 11 surface-collected dust samples to investigate the role of different minerals for atmospheric ice nucleation on desert dust. We find that present K-feldspars dominate at T > 253 K, while quartz does at colder temperatures, and surface-collected dust samples are not necessarily representative for airborne dust. For improved ice cloud prediction, modeling of quartz and feldspar emission and transport are key.
Baban Nagare, Claudia Marcolli, André Welti, Olaf Stetzer, and Ulrike Lohmann
Atmos. Chem. Phys., 16, 8899–8914, https://doi.org/10.5194/acp-16-8899-2016, https://doi.org/10.5194/acp-16-8899-2016, 2016
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The relative importance of contact freezing and immersion freezing at mixed-phase cloud temperatures is the subject of debate. We performed experiments using continuous-flow diffusion chambers to compare the freezing efficiency of ice-nucleating particles for both these nucleation modes. Silver iodide, kaolinite and Arizona Test Dust were used as ice-nucleating particles. We could not confirm the dominance of contact freezing over immersion freezing for our experimental conditions.
Claudia Marcolli, Baban Nagare, André Welti, and Ulrike Lohmann
Atmos. Chem. Phys., 16, 8915–8937, https://doi.org/10.5194/acp-16-8915-2016, https://doi.org/10.5194/acp-16-8915-2016, 2016
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Silver iodide is one of the best-investigated ice nuclei. It has relevance for the atmosphere since it is used for glaciogenic cloud seeding. Nevertheless, many open questions remain. This paper gives an overview of silver iodide as an ice nucleus and tries to identify the factors that influence the ice nucleation ability of silver iodide.
Sarvesh Garimella, Thomas Bjerring Kristensen, Karolina Ignatius, Andre Welti, Jens Voigtländer, Gourihar R. Kulkarni, Frank Sagan, Gregory Lee Kok, James Dorsey, Leonid Nichman, Daniel Alexander Rothenberg, Michael Rösch, Amélie Catharina Ruth Kirchgäßner, Russell Ladkin, Heike Wex, Theodore W. Wilson, Luis Antonio Ladino, Jon P. D. Abbatt, Olaf Stetzer, Ulrike Lohmann, Frank Stratmann, and Daniel James Cziczo
Atmos. Meas. Tech., 9, 2781–2795, https://doi.org/10.5194/amt-9-2781-2016, https://doi.org/10.5194/amt-9-2781-2016, 2016
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The SPectrometer for Ice Nuclei (SPIN) is a commercially available ice nuclei counter manufactured by Droplet Measurement Technologies in Boulder, CO. This study characterizes the SPIN chamber, reporting data from laboratory measurements and quantifying uncertainties. Overall, we report that the SPIN is able to reproduce previous CFDC ice nucleation measurements.
Charles A. Brock, Nicholas L. Wagner, Bruce E. Anderson, Alexis R. Attwood, Andreas Beyersdorf, Pedro Campuzano-Jost, Annmarie G. Carlton, Douglas A. Day, Glenn S. Diskin, Timothy D. Gordon, Jose L. Jimenez, Daniel A. Lack, Jin Liao, Milos Z. Markovic, Ann M. Middlebrook, Nga L. Ng, Anne E. Perring, Matthews S. Richardson, Joshua P. Schwarz, Rebecca A. Washenfelder, Andre Welti, Lu Xu, Luke D. Ziemba, and Daniel M. Murphy
Atmos. Chem. Phys., 16, 4987–5007, https://doi.org/10.5194/acp-16-4987-2016, https://doi.org/10.5194/acp-16-4987-2016, 2016
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Microscopic pollution particles make the atmosphere look hazy and also cool the earth by sending sunlight back to space. When the air is moist, these particles swell with water and scatter even more sunlight. We showed that particles formed from organic material – which dominates particulate pollution in the southeastern U.S. – does not take up water very effectively, toward the low end of most previous studies. We also found a better way to mathematically describe this swelling process.
Charles A. Brock, Nicholas L. Wagner, Bruce E. Anderson, Andreas Beyersdorf, Pedro Campuzano-Jost, Douglas A. Day, Glenn S. Diskin, Timothy D. Gordon, Jose L. Jimenez, Daniel A. Lack, Jin Liao, Milos Z. Markovic, Ann M. Middlebrook, Anne E. Perring, Matthews S. Richardson, Joshua P. Schwarz, Andre Welti, Luke D. Ziemba, and Daniel M. Murphy
Atmos. Chem. Phys., 16, 5009–5019, https://doi.org/10.5194/acp-16-5009-2016, https://doi.org/10.5194/acp-16-5009-2016, 2016
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Two research aircraft made dozens of vertical profiles over rural areas in the southeastern US in summer 2013. These measurements show that, in addition to how much pollution was present and how moist the atmosphere was, the size of the pollutant particles affected how much sunlight was reflected back to space. These measurements will help climate modelers determine which characteristics of pollution are important to predict with accuracy.
P. S. Kim, D. J. Jacob, J. A. Fisher, K. Travis, K. Yu, L. Zhu, R. M. Yantosca, M. P. Sulprizio, J. L. Jimenez, P. Campuzano-Jost, K. D. Froyd, J. Liao, J. W. Hair, M. A. Fenn, C. F. Butler, N. L. Wagner, T. D. Gordon, A. Welti, P. O. Wennberg, J. D. Crounse, J. M. St. Clair, A. P. Teng, D. B. Millet, J. P. Schwarz, M. Z. Markovic, and A. E. Perring
Atmos. Chem. Phys., 15, 10411–10433, https://doi.org/10.5194/acp-15-10411-2015, https://doi.org/10.5194/acp-15-10411-2015, 2015
N. L. Wagner, C. A. Brock, W. M. Angevine, A. Beyersdorf, P. Campuzano-Jost, D. Day, J. A. de Gouw, G. S. Diskin, T. D. Gordon, M. G. Graus, J. S. Holloway, G. Huey, J. L. Jimenez, D. A. Lack, J. Liao, X. Liu, M. Z. Markovic, A. M. Middlebrook, T. Mikoviny, J. Peischl, A. E. Perring, M. S. Richardson, T. B. Ryerson, J. P. Schwarz, C. Warneke, A. Welti, A. Wisthaler, L. D. Ziemba, and D. M. Murphy
Atmos. Chem. Phys., 15, 7085–7102, https://doi.org/10.5194/acp-15-7085-2015, https://doi.org/10.5194/acp-15-7085-2015, 2015
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This paper investigates the summertime vertical profile of aerosol over the southeastern US using in situ measurements collected from aircraft. We use a vertical mixing model and measurements of CO to predict the vertical profile of aerosol that we would expect from vertical mixing alone and compare with the observed aerosol profile. We found a modest enhancement of aerosol in the cloudy transition layer during shallow cumulus convection and attribute the enhancement to local aerosol formation.
N. Hiranuma, S. Augustin-Bauditz, H. Bingemer, C. Budke, J. Curtius, A. Danielczok, K. Diehl, K. Dreischmeier, M. Ebert, F. Frank, N. Hoffmann, K. Kandler, A. Kiselev, T. Koop, T. Leisner, O. Möhler, B. Nillius, A. Peckhaus, D. Rose, S. Weinbruch, H. Wex, Y. Boose, P. J. DeMott, J. D. Hader, T. C. J. Hill, Z. A. Kanji, G. Kulkarni, E. J. T. Levin, C. S. McCluskey, M. Murakami, B. J. Murray, D. Niedermeier, M. D. Petters, D. O'Sullivan, A. Saito, G. P. Schill, T. Tajiri, M. A. Tolbert, A. Welti, T. F. Whale, T. P. Wright, and K. Yamashita
Atmos. Chem. Phys., 15, 2489–2518, https://doi.org/10.5194/acp-15-2489-2015, https://doi.org/10.5194/acp-15-2489-2015, 2015
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Seventeen ice nucleation measurement techniques contributed to investigate the immersion freezing behavior of illite NX. All data showed a similar temperature trend, but the measured ice nucleation activity was on average smaller for the wet suspended samples and higher for the dry-dispersed aerosol samples at high temperatures. A continued investigation and collaboration is necessary to obtain further insights into consistency or diversity of ice nucleation measurements.
Z. A. Kanji, A. Welti, C. Chou, O. Stetzer, and U. Lohmann
Atmos. Chem. Phys., 13, 9097–9118, https://doi.org/10.5194/acp-13-9097-2013, https://doi.org/10.5194/acp-13-9097-2013, 2013
Zsófia Jurányi, Christof Lüpkes, Frank Stratmann, Jörg Hartmann, Jonas Schaefer, Anna-Marie Jörss, Alexander Schulz, Bruno Wetzel, David Simon, Eduard Gebhard, Maximilian Stöhr, Paula Hofmann, Dirk Kalmbach, Sarah Grawe, Manfred Wendisch, and Andreas Herber
Atmos. Meas. Tech., 18, 3477–3494, https://doi.org/10.5194/amt-18-3477-2025, https://doi.org/10.5194/amt-18-3477-2025, 2025
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Understanding the lowest layers of the atmosphere is crucial for climate research, especially in the Arctic. Our study introduces the T-Bird, an aircraft-towed platform designed to measure turbulence and aerosol properties at extremely low altitudes. Traditional aircraft cannot access this region, making the T-Bird a breakthrough for capturing critical atmospheric data. Its first deployment over the Arctic demonstrated its potential to improve our understanding of polar processes.
Guangyu Li, André Welti, Iris Thurnherr, Ulrike Lohmann, and Zamin A. Kanji
EGUsphere, https://doi.org/10.5194/egusphere-2025-2798, https://doi.org/10.5194/egusphere-2025-2798, 2025
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This study presents ship-based measurements of summertime ice-nucleating particles (INPs) over the data-scarce Eurasian-Arctic Seas. We found that INPs are driven by both local and regional sources, with the highest levels observed near land and over ice-free waters. This study is highlighted for improving the understanding of INP abundance, sources, and their role in cloud processes in the rapidly warming Arctic.
Kaiqi Wang, Kai Bi, Shuling Chen, Markus Hartmann, Zhijun Wu, Jiyu Gao, Xiaoyu Xu, Yuhan Cheng, Mengyu Huang, Yunbo Chen, Huiwen Xue, Bingbing Wang, Yaqiong Hu, Xiongying Zhang, Xincheng Ma, Ruijie Li, Ping Tian, Ottmar Möhler, Heike Wex, Frank Startmann, Jie Chen, and Xianda Gong
EGUsphere, https://doi.org/10.5194/egusphere-2025-1873, https://doi.org/10.5194/egusphere-2025-1873, 2025
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Understanding how ice forms in clouds is crucial for predicting weather and climate; however, accurately measuring the ice-nucleating particles that trigger ice formation remains challenging. We developed an advanced instrument called the Freezing Ice Nucleation Detection Analyzer. By refining temperature control, automating freezing detection, and rigorously testing, we demonstrated that this instrument can reliably measure ice-nucleating particles across diverse conditions.
Dennis Niedermeier, Rasmus Hoffmann, Silvio Schmalfuss, Wiebke Frey, Fabian Senf, Olaf Hellmuth, Mira Pöhlker, and Frank Stratmann
Aerosol Research, 3, 219–230, https://doi.org/10.5194/ar-3-219-2025, https://doi.org/10.5194/ar-3-219-2025, 2025
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This study examines the deliquescence behavior of NaCl particles in a turbulent humidity field using the wind tunnel LACIS-T (Turbulent Leipzig Aerosol Cloud Interaction Simulator). The results show that turbulent relative humidity (RH) fluctuations affect the number of deliquesced particles, depending on the mean RH, strength of humidity fluctuations, and particle residence time. It turns out that, in addition to the mean RH, it is essential to consider humidity fluctuations and particle history when determining the phase state of the deliquescent particles.
André Ehrlich, Susanne Crewell, Andreas Herber, Marcus Klingebiel, Christof Lüpkes, Mario Mech, Sebastian Becker, Stephan Borrmann, Heiko Bozem, Matthias Buschmann, Hans-Christian Clemen, Elena De La Torre Castro, Henning Dorff, Regis Dupuy, Oliver Eppers, Florian Ewald, Geet George, Andreas Giez, Sarah Grawe, Christophe Gourbeyre, Jörg Hartmann, Evelyn Jäkel, Philipp Joppe, Olivier Jourdan, Zsófia Jurányi, Benjamin Kirbus, Johannes Lucke, Anna E. Luebke, Maximilian Maahn, Nina Maherndl, Christian Mallaun, Johanna Mayer, Stephan Mertes, Guillaume Mioche, Manuel Moser, Hanno Müller, Veronika Pörtge, Nils Risse, Greg Roberts, Sophie Rosenburg, Johannes Röttenbacher, Michael Schäfer, Jonas Schaefer, Andreas Schäfler, Imke Schirmacher, Johannes Schneider, Sabrina Schnitt, Frank Stratmann, Christian Tatzelt, Christiane Voigt, Andreas Walbröl, Anna Weber, Bruno Wetzel, Martin Wirth, and Manfred Wendisch
Earth Syst. Sci. Data, 17, 1295–1328, https://doi.org/10.5194/essd-17-1295-2025, https://doi.org/10.5194/essd-17-1295-2025, 2025
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This paper provides an overview of the HALO–(AC)3 aircraft campaign data sets, the campaign-specific instrument operation, data processing, and data quality. The data set comprises in situ and remote sensing observations from three research aircraft: HALO, Polar 5, and Polar 6. All data are published in the PANGAEA database by instrument-separated data subsets. It is highlighted how the scientific analysis of the HALO–(AC)3 data benefits from the coordinated operation of three aircraft.
Olivia G. Norman, Colette L. Heald, Solomon Bililign, Pedro Campuzano-Jost, Hugh Coe, Marc N. Fiddler, Jaime R. Green, Jose L. Jimenez, Katharina Kaiser, Jin Liao, Ann M. Middlebrook, Benjamin A. Nault, John B. Nowak, Johannes Schneider, and André Welti
Atmos. Chem. Phys., 25, 771–795, https://doi.org/10.5194/acp-25-771-2025, https://doi.org/10.5194/acp-25-771-2025, 2025
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This study finds that one component of secondary inorganic aerosols, nitrate, is greatly overestimated by a global atmospheric chemistry model compared to observations from 11 flight campaigns. None of the loss and production pathways explored can explain the nitrate bias alone. The model’s inability to capture the variability in the observations remains and requires future investigation to avoid biases in policy-related studies (i.e., air quality, health, climate impacts of these aerosols).
Ari Laaksonen, Golnaz Roudsari, Ana A. Piedehierro, and André Welti
EGUsphere, https://doi.org/10.5194/egusphere-2024-4095, https://doi.org/10.5194/egusphere-2024-4095, 2025
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The mechanisms of ice nucleation at temperatures below 235 K have remained unclear for the past century. We suggest that ice nucleation is caused by the freezing of water adsorbed on aerosol surfaces. To test this hypothesis, we derived theoretical equations to predict the exact atmospheric conditions under which ice nucleation occurs. Our predictions agree well with experiments. The new theory thus provides a basis for an improved description of ice nucleation in the atmosphere.
Manfred Wendisch, Susanne Crewell, André Ehrlich, Andreas Herber, Benjamin Kirbus, Christof Lüpkes, Mario Mech, Steven J. Abel, Elisa F. Akansu, Felix Ament, Clémantyne Aubry, Sebastian Becker, Stephan Borrmann, Heiko Bozem, Marlen Brückner, Hans-Christian Clemen, Sandro Dahlke, Georgios Dekoutsidis, Julien Delanoë, Elena De La Torre Castro, Henning Dorff, Regis Dupuy, Oliver Eppers, Florian Ewald, Geet George, Irina V. Gorodetskaya, Sarah Grawe, Silke Groß, Jörg Hartmann, Silvia Henning, Lutz Hirsch, Evelyn Jäkel, Philipp Joppe, Olivier Jourdan, Zsofia Jurányi, Michail Karalis, Mona Kellermann, Marcus Klingebiel, Michael Lonardi, Johannes Lucke, Anna E. Luebke, Maximilian Maahn, Nina Maherndl, Marion Maturilli, Bernhard Mayer, Johanna Mayer, Stephan Mertes, Janosch Michaelis, Michel Michalkov, Guillaume Mioche, Manuel Moser, Hanno Müller, Roel Neggers, Davide Ori, Daria Paul, Fiona M. Paulus, Christian Pilz, Felix Pithan, Mira Pöhlker, Veronika Pörtge, Maximilian Ringel, Nils Risse, Gregory C. Roberts, Sophie Rosenburg, Johannes Röttenbacher, Janna Rückert, Michael Schäfer, Jonas Schaefer, Vera Schemann, Imke Schirmacher, Jörg Schmidt, Sebastian Schmidt, Johannes Schneider, Sabrina Schnitt, Anja Schwarz, Holger Siebert, Harald Sodemann, Tim Sperzel, Gunnar Spreen, Bjorn Stevens, Frank Stratmann, Gunilla Svensson, Christian Tatzelt, Thomas Tuch, Timo Vihma, Christiane Voigt, Lea Volkmer, Andreas Walbröl, Anna Weber, Birgit Wehner, Bruno Wetzel, Martin Wirth, and Tobias Zinner
Atmos. Chem. Phys., 24, 8865–8892, https://doi.org/10.5194/acp-24-8865-2024, https://doi.org/10.5194/acp-24-8865-2024, 2024
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The Arctic is warming faster than the rest of the globe. Warm-air intrusions (WAIs) into the Arctic may play an important role in explaining this phenomenon. Cold-air outbreaks (CAOs) out of the Arctic may link the Arctic climate changes to mid-latitude weather. In our article, we describe how to observe air mass transformations during CAOs and WAIs using three research aircraft instrumented with state-of-the-art remote-sensing and in situ measurement devices.
Johanna S. Seidel, Alexei A. Kiselev, Alice Keinert, Frank Stratmann, Thomas Leisner, and Susan Hartmann
Atmos. Chem. Phys., 24, 5247–5263, https://doi.org/10.5194/acp-24-5247-2024, https://doi.org/10.5194/acp-24-5247-2024, 2024
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Clouds often contain several thousand times more ice crystals than aerosol particles catalyzing ice formation. This phenomenon, commonly known as ice multiplication, is often explained by secondary ice formation due to the collisions between falling ice particles and droplets. In this study, we mimic this riming process. Contrary to earlier experiments, we found no efficient ice multiplication, which fundamentally questions the importance of the rime-splintering mechanism.
Larissa Lacher, Michael P. Adams, Kevin Barry, Barbara Bertozzi, Heinz Bingemer, Cristian Boffo, Yannick Bras, Nicole Büttner, Dimitri Castarede, Daniel J. Cziczo, Paul J. DeMott, Romy Fösig, Megan Goodell, Kristina Höhler, Thomas C. J. Hill, Conrad Jentzsch, Luis A. Ladino, Ezra J. T. Levin, Stephan Mertes, Ottmar Möhler, Kathryn A. Moore, Benjamin J. Murray, Jens Nadolny, Tatjana Pfeuffer, David Picard, Carolina Ramírez-Romero, Mickael Ribeiro, Sarah Richter, Jann Schrod, Karine Sellegri, Frank Stratmann, Benjamin E. Swanson, Erik S. Thomson, Heike Wex, Martin J. Wolf, and Evelyn Freney
Atmos. Chem. Phys., 24, 2651–2678, https://doi.org/10.5194/acp-24-2651-2024, https://doi.org/10.5194/acp-24-2651-2024, 2024
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Aerosol particles that trigger ice formation in clouds are important for the climate system but are very rare in the atmosphere, challenging measurement techniques. Here we compare three cloud chambers and seven methods for collecting aerosol particles on filters for offline analysis at a mountaintop station. A general good agreement of the methods was found when sampling aerosol particles behind a whole air inlet, supporting their use for obtaining data that can be implemented in models.
Sarah Grawe, Conrad Jentzsch, Jonas Schaefer, Heike Wex, Stephan Mertes, and Frank Stratmann
Atmos. Meas. Tech., 16, 4551–4570, https://doi.org/10.5194/amt-16-4551-2023, https://doi.org/10.5194/amt-16-4551-2023, 2023
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Measurements of ice-nucleating particle (INP) concentrations are valuable for the simulation of cloud properties. In recent years, filter sampling in combination with offline INP measurements has become increasingly popular. However, most sampling is ground-based, and the vertical transport of INPs is not well quantified. The High-volume flow aERosol particle filter sAmpler (HERA) for applications on board aircraft was developed to expand the sparse dataset of INP concentrations at cloud level.
Hannah C. Frostenberg, André Welti, Mikael Luhr, Julien Savre, Erik S. Thomson, and Luisa Ickes
Atmos. Chem. Phys., 23, 10883–10900, https://doi.org/10.5194/acp-23-10883-2023, https://doi.org/10.5194/acp-23-10883-2023, 2023
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Observations show that ice-nucleating particle concentrations (INPCs) have a large variety and follow lognormal distributions for a given temperature. We introduce a new immersion freezing parameterization that applies this lognormal behavior. INPCs are drawn randomly from a temperature-dependent lognormal distribution. We then show that the ice content of the modeled Arctic stratocumulus cloud is highly sensitive to the probability of drawing large INPCs.
Dimitri Castarède, Zoé Brasseur, Yusheng Wu, Zamin A. Kanji, Markus Hartmann, Lauri Ahonen, Merete Bilde, Markku Kulmala, Tuukka Petäjä, Jan B. C. Pettersson, Berko Sierau, Olaf Stetzer, Frank Stratmann, Birgitta Svenningsson, Erik Swietlicki, Quynh Thu Nguyen, Jonathan Duplissy, and Erik S. Thomson
Atmos. Meas. Tech., 16, 3881–3899, https://doi.org/10.5194/amt-16-3881-2023, https://doi.org/10.5194/amt-16-3881-2023, 2023
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Clouds play a key role in Earth’s climate by influencing the surface energy budget. Certain types of atmospheric aerosols, called ice-nucleating particles (INPs), induce the formation of ice in clouds and, thus, often initiate precipitation formation. The Portable Ice Nucleation Chamber 2 (PINCii) is a new instrument developed to study ice formation and to conduct ambient measurements of INPs, allowing us to investigate the sources and properties of the atmospheric aerosols that can act as INPs.
Joschka Pfeifer, Naser G. A. Mahfouz, Benjamin C. Schulze, Serge Mathot, Dominik Stolzenburg, Rima Baalbaki, Zoé Brasseur, Lucia Caudillo, Lubna Dada, Manuel Granzin, Xu-Cheng He, Houssni Lamkaddam, Brandon Lopez, Vladimir Makhmutov, Ruby Marten, Bernhard Mentler, Tatjana Müller, Antti Onnela, Maxim Philippov, Ana A. Piedehierro, Birte Rörup, Meredith Schervish, Ping Tian, Nsikanabasi S. Umo, Dongyu S. Wang, Mingyi Wang, Stefan K. Weber, André Welti, Yusheng Wu, Marcel Zauner-Wieczorek, Antonio Amorim, Imad El Haddad, Markku Kulmala, Katrianne Lehtipalo, Tuukka Petäjä, António Tomé, Sander Mirme, Hanna E. Manninen, Neil M. Donahue, Richard C. Flagan, Andreas Kürten, Joachim Curtius, and Jasper Kirkby
Atmos. Chem. Phys., 23, 6703–6718, https://doi.org/10.5194/acp-23-6703-2023, https://doi.org/10.5194/acp-23-6703-2023, 2023
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Attachment rate coefficients between ions and charged aerosol particles determine their lifetimes and may also influence cloud dynamics and aerosol processing. Here we present novel experiments that measure ion–aerosol attachment rate coefficients for multiply charged aerosol particles under atmospheric conditions in the CERN CLOUD chamber. Our results provide experimental discrimination between various theoretical models.
Lucía Caudillo, Mihnea Surdu, Brandon Lopez, Mingyi Wang, Markus Thoma, Steffen Bräkling, Angela Buchholz, Mario Simon, Andrea C. Wagner, Tatjana Müller, Manuel Granzin, Martin Heinritzi, Antonio Amorim, David M. Bell, Zoé Brasseur, Lubna Dada, Jonathan Duplissy, Henning Finkenzeller, Xu-Cheng He, Houssni Lamkaddam, Naser G. A. Mahfouz, Vladimir Makhmutov, Hanna E. Manninen, Guillaume Marie, Ruby Marten, Roy L. Mauldin, Bernhard Mentler, Antti Onnela, Tuukka Petäjä, Joschka Pfeifer, Maxim Philippov, Ana A. Piedehierro, Birte Rörup, Wiebke Scholz, Jiali Shen, Dominik Stolzenburg, Christian Tauber, Ping Tian, António Tomé, Nsikanabasi Silas Umo, Dongyu S. Wang, Yonghong Wang, Stefan K. Weber, André Welti, Marcel Zauner-Wieczorek, Urs Baltensperger, Richard C. Flagan, Armin Hansel, Jasper Kirkby, Markku Kulmala, Katrianne Lehtipalo, Douglas R. Worsnop, Imad El Haddad, Neil M. Donahue, Alexander L. Vogel, Andreas Kürten, and Joachim Curtius
Atmos. Chem. Phys., 23, 6613–6631, https://doi.org/10.5194/acp-23-6613-2023, https://doi.org/10.5194/acp-23-6613-2023, 2023
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In this study, we present an intercomparison of four different techniques for measuring the chemical composition of nanoparticles. The intercomparison was performed based on the observed chemical composition, calculated volatility, and analysis of the thermograms. We found that the methods generally agree on the most important compounds that are found in the nanoparticles. However, they do see different parts of the organic spectrum. We suggest potential explanations for these differences.
Kevin C. H. Sze, Heike Wex, Markus Hartmann, Henrik Skov, Andreas Massling, Diego Villanueva, and Frank Stratmann
Atmos. Chem. Phys., 23, 4741–4761, https://doi.org/10.5194/acp-23-4741-2023, https://doi.org/10.5194/acp-23-4741-2023, 2023
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Ice-nucleating particles (INPs) play an important role in cloud formation and thus in our climate. But little is known about the abundance and properties of INPs, especially in the Arctic, where the temperature increases almost 4 times as fast as that of the rest of the globe. We observe higher INP concentrations and more biological INPs in summer than in winter, likely from local sources. We also provide three equations for estimating INP concentrations in models at different times of the year.
Yuan Wang, Silvia Henning, Laurent Poulain, Chunsong Lu, Frank Stratmann, Yuying Wang, Shengjie Niu, Mira L. Pöhlker, Hartmut Herrmann, and Alfred Wiedensohler
Atmos. Chem. Phys., 22, 15943–15962, https://doi.org/10.5194/acp-22-15943-2022, https://doi.org/10.5194/acp-22-15943-2022, 2022
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Aerosol particle activation affects cloud, precipitation, radiation, and thus the global climate. Its long-term measurements are important but still scarce. In this study, more than 4 years of measurements at a central European station were analyzed. The overall characteristics and seasonal changes of aerosol particle activation are summarized. The power-law fit between particle hygroscopicity factor and diameter was recommended for predicting cloud
condensation nuclei number concentration.
Xianda Gong, Martin Radenz, Heike Wex, Patric Seifert, Farnoush Ataei, Silvia Henning, Holger Baars, Boris Barja, Albert Ansmann, and Frank Stratmann
Atmos. Chem. Phys., 22, 10505–10525, https://doi.org/10.5194/acp-22-10505-2022, https://doi.org/10.5194/acp-22-10505-2022, 2022
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The sources of ice-nucleating particles (INPs) are poorly understood in the Southern Hemisphere (SH). We studied INPs in the boundary layer in the southern Patagonia region. No seasonal cycle of INP concentrations was observed. The majority of INPs are biogenic particles, likely from local continental sources. The INP concentrations are higher when strong precipitation occurs. While previous studies focused on marine INP sources in SH, we point out the importance of continental sources of INPs.
Christian Tatzelt, Silvia Henning, André Welti, Andrea Baccarini, Markus Hartmann, Martin Gysel-Beer, Manuela van Pinxteren, Robin L. Modini, Julia Schmale, and Frank Stratmann
Atmos. Chem. Phys., 22, 9721–9745, https://doi.org/10.5194/acp-22-9721-2022, https://doi.org/10.5194/acp-22-9721-2022, 2022
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We present the abundance and origin of cloud-relevant aerosol particles in the preindustral-like conditions of the Southern Ocean (SO) during austral summer. Cloud condensation nuclei (CCN) and ice-nucleating particles (INP) were measured during a circum-Antarctic scientific cruise with in situ instrumentation and offline filter measurements, respectively. Transport processes were found to play an equally important role as local sources for both the CCN and INP population of the SO.
Jakub L. Nowak, Robert Grosz, Wiebke Frey, Dennis Niedermeier, Jędrzej Mijas, Szymon P. Malinowski, Linda Ort, Silvio Schmalfuß, Frank Stratmann, Jens Voigtländer, and Tadeusz Stacewicz
Atmos. Meas. Tech., 15, 4075–4089, https://doi.org/10.5194/amt-15-4075-2022, https://doi.org/10.5194/amt-15-4075-2022, 2022
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A high-resolution infrared hygrometer (FIRH) was adapted to measure humidity and its rapid fluctuations in turbulence inside a moist-air wind tunnel LACIS-T where two air streams of different temperature and humidity are mixed. The measurement was achieved from outside the tunnel through its glass windows and provided an agreement with a reference dew-point hygrometer placed inside. The characterization of humidity complements previous investigations of velocity and temperature fields.
Manuela van Pinxteren, Tiera-Brandy Robinson, Sebastian Zeppenfeld, Xianda Gong, Enno Bahlmann, Khanneh Wadinga Fomba, Nadja Triesch, Frank Stratmann, Oliver Wurl, Anja Engel, Heike Wex, and Hartmut Herrmann
Atmos. Chem. Phys., 22, 5725–5742, https://doi.org/10.5194/acp-22-5725-2022, https://doi.org/10.5194/acp-22-5725-2022, 2022
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A class of marine particles (transparent exopolymer particles, TEPs) that is ubiquitously found in the world oceans was measured for the first time in ambient marine aerosol particles and marine cloud waters in the tropical Atlantic Ocean. TEPs are likely to have good properties for influencing clouds. We show that TEPs are transferred from the ocean to the marine atmosphere via sea-spray formation and our results suggest that they can also form directly in aerosol particles and in cloud water.
Xianda Gong, Heike Wex, Thomas Müller, Silvia Henning, Jens Voigtländer, Alfred Wiedensohler, and Frank Stratmann
Atmos. Chem. Phys., 22, 5175–5194, https://doi.org/10.5194/acp-22-5175-2022, https://doi.org/10.5194/acp-22-5175-2022, 2022
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We conducted 10 yr measurements to characterize the atmospheric aerosol at Cabo Verde. An unsupervised machine learning algorithm, K-means, was implemented to study the aerosol types. Cloud condensation nuclei number concentrations during dust periods were 2.5 times higher than marine periods. The long-term data sets, together with the aerosol classification, can be used as a basis to improve understanding of annual cycles of aerosol, and aerosol-cloud interactions in the North Atlantic.
Rupert Holzinger, Oliver Eppers, Kouji Adachi, Heiko Bozem, Markus Hartmann, Andreas Herber, Makoto Koike, Dylan B. Millet, Nobuhiro Moteki, Sho Ohata, Frank Stratmann, and Atsushi Yoshida
Atmos. Chem. Phys. Discuss., https://doi.org/10.5194/acp-2022-95, https://doi.org/10.5194/acp-2022-95, 2022
Revised manuscript not accepted
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In spring 2018 the research aircraft Polar 5 conducted flights in the Arctic atmosphere. The flight operation was from Station Nord in Greenland, 1700 km north of the Arctic Circle (81°43'N, 17°47'W). Using a mass spectrometer we measured more than 100 organic compounds in the air. We found a clear signature of natural organic compounds that are transported from forests to the high Arctic. These compounds have the potential to change the cloud cover and energy budget of the Arctic region.
Lucía Caudillo, Birte Rörup, Martin Heinritzi, Guillaume Marie, Mario Simon, Andrea C. Wagner, Tatjana Müller, Manuel Granzin, Antonio Amorim, Farnoush Ataei, Rima Baalbaki, Barbara Bertozzi, Zoé Brasseur, Randall Chiu, Biwu Chu, Lubna Dada, Jonathan Duplissy, Henning Finkenzeller, Loïc Gonzalez Carracedo, Xu-Cheng He, Victoria Hofbauer, Weimeng Kong, Houssni Lamkaddam, Chuan P. Lee, Brandon Lopez, Naser G. A. Mahfouz, Vladimir Makhmutov, Hanna E. Manninen, Ruby Marten, Dario Massabò, Roy L. Mauldin, Bernhard Mentler, Ugo Molteni, Antti Onnela, Joschka Pfeifer, Maxim Philippov, Ana A. Piedehierro, Meredith Schervish, Wiebke Scholz, Benjamin Schulze, Jiali Shen, Dominik Stolzenburg, Yuri Stozhkov, Mihnea Surdu, Christian Tauber, Yee Jun Tham, Ping Tian, António Tomé, Steffen Vogt, Mingyi Wang, Dongyu S. Wang, Stefan K. Weber, André Welti, Wang Yonghong, Wu Yusheng, Marcel Zauner-Wieczorek, Urs Baltensperger, Imad El Haddad, Richard C. Flagan, Armin Hansel, Kristina Höhler, Jasper Kirkby, Markku Kulmala, Katrianne Lehtipalo, Ottmar Möhler, Harald Saathoff, Rainer Volkamer, Paul M. Winkler, Neil M. Donahue, Andreas Kürten, and Joachim Curtius
Atmos. Chem. Phys., 21, 17099–17114, https://doi.org/10.5194/acp-21-17099-2021, https://doi.org/10.5194/acp-21-17099-2021, 2021
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We performed experiments in the CLOUD chamber at CERN at low temperatures to simulate new particle formation in the upper free troposphere (at −30 ºC and −50 ºC). We measured the particle and gas phase and found that most of the compounds present in the gas phase are detected as well in the particle phase. The major compounds in the particles are C8–10 and C18–20. Specifically, we showed that C5 and C15 compounds are detected in a mixed system with isoprene and α-pinene at −30 ºC, 20 % RH.
Markus Hartmann, Xianda Gong, Simonas Kecorius, Manuela van Pinxteren, Teresa Vogl, André Welti, Heike Wex, Sebastian Zeppenfeld, Hartmut Herrmann, Alfred Wiedensohler, and Frank Stratmann
Atmos. Chem. Phys., 21, 11613–11636, https://doi.org/10.5194/acp-21-11613-2021, https://doi.org/10.5194/acp-21-11613-2021, 2021
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Ice-nucleating particles (INPs) are not well characterized in the Arctic despite their importance for the Arctic energy budget. Little is known about their nature (mineral or biological) and sources (terrestrial or marine, long-range transport or local). We find indications that, at the beginning of the melt season, a local, biogenic, probably marine source is likely, but significant enrichment of INPs has to take place from the ocean to the aerosol phase.
Ana A. Piedehierro, André Welti, Angela Buchholz, Kimmo Korhonen, Iida Pullinen, Ilkka Summanen, Annele Virtanen, and Ari Laaksonen
Atmos. Chem. Phys., 21, 11069–11078, https://doi.org/10.5194/acp-21-11069-2021, https://doi.org/10.5194/acp-21-11069-2021, 2021
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Ice crystals in cirrus clouds contain particles that start ice formation. We study whether particles forming above boreal forests can help in the making of cirrus clouds and if the water content in the particles affects this property. In the laboratory, we made boreal-forest-like particles and cooled and humidified them to measure whether an ice crystal develops. We found that only when dry can these particles form an ice crystal but no better than solution droplets.
Laurent Poulain, Benjamin Fahlbusch, Gerald Spindler, Konrad Müller, Dominik van Pinxteren, Zhijun Wu, Yoshiteru Iinuma, Wolfram Birmili, Alfred Wiedensohler, and Hartmut Herrmann
Atmos. Chem. Phys., 21, 3667–3684, https://doi.org/10.5194/acp-21-3667-2021, https://doi.org/10.5194/acp-21-3667-2021, 2021
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We present results from source apportionment analysis on the carbonaceous aerosol particles, including organic aerosol (OA) and equivalent black carbon (eBC), allowing us to distinguish local emissions from long-range transport for OA and eBC sources. By merging online chemical measurements and considering particle number size distribution, the different air masses reaching the sampling place were described and discussed, based on their respective chemical composition and size distribution.
André Welti, Kimmo Korhonen, Pasi Miettinen, Ana A. Piedehierro, Yrjö Viisanen, Annele Virtanen, and Ari Laaksonen
Atmos. Meas. Tech., 13, 7059–7067, https://doi.org/10.5194/amt-13-7059-2020, https://doi.org/10.5194/amt-13-7059-2020, 2020
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We describe a modification of the SPectrometer for Ice Nuclei (SPIN) chamber to study ice nucleation at low temperatures, relevant for ice formation in cirrus clouds. Validation experiments of homogeneous freezing of aqueous ammonium sulfate droplets and heterogeneous ice nucleation on silver iodide particles are included to demonstrate the advantages of the modified SPIN chamber for the investigation of ice nucleation in the extended temperature range.
André Welti, E. Keith Bigg, Paul J. DeMott, Xianda Gong, Markus Hartmann, Mike Harvey, Silvia Henning, Paul Herenz, Thomas C. J. Hill, Blake Hornblow, Caroline Leck, Mareike Löffler, Christina S. McCluskey, Anne Marie Rauker, Julia Schmale, Christian Tatzelt, Manuela van Pinxteren, and Frank Stratmann
Atmos. Chem. Phys., 20, 15191–15206, https://doi.org/10.5194/acp-20-15191-2020, https://doi.org/10.5194/acp-20-15191-2020, 2020
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Ship-based measurements of maritime ice nuclei concentrations encompassing all oceans are compiled. From this overview it is found that maritime ice nuclei concentrations are typically 10–100 times lower than over continents, while concentrations are surprisingly similar in different oceanic regions. The analysis of the influence of ship emissions shows no effect on the data, making ship-based measurements an efficient strategy for the large-scale exploration of ice nuclei concentrations.
Hans-Christian Clemen, Johannes Schneider, Thomas Klimach, Frank Helleis, Franziska Köllner, Andreas Hünig, Florian Rubach, Stephan Mertes, Heike Wex, Frank Stratmann, André Welti, Rebecca Kohl, Fabian Frank, and Stephan Borrmann
Atmos. Meas. Tech., 13, 5923–5953, https://doi.org/10.5194/amt-13-5923-2020, https://doi.org/10.5194/amt-13-5923-2020, 2020
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We improved the efficiency of a single-particle mass spectrometer with a newly developed aerodynamic lens system, delayed ion extraction, and better electric shielding. The new components result in significantly improved particle analysis and sample statistics. This is particularly important for measurements of low-number-density particles, such as ice-nucleating particles, and for aircraft-based measurements at high altitudes or where high temporal and spatial resolution is required.
Aikaterini Bougiatioti, Athanasios Nenes, Jack J. Lin, Charles A. Brock, Joost A. de Gouw, Jin Liao, Ann M. Middlebrook, and André Welti
Atmos. Chem. Phys., 20, 12163–12176, https://doi.org/10.5194/acp-20-12163-2020, https://doi.org/10.5194/acp-20-12163-2020, 2020
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The number concentration of droplets in clouds in the summertime in the southeastern United States is influenced by aerosol variations but limited by the strong competition for supersaturated water vapor. Concurrent variations in vertical velocity magnify the response of cloud droplet number to aerosol increases by up to a factor of 5. Omitting the covariance of vertical velocity with aerosol number may therefore bias estimates of the cloud albedo effect from aerosols.
Leighton A. Regayre, Julia Schmale, Jill S. Johnson, Christian Tatzelt, Andrea Baccarini, Silvia Henning, Masaru Yoshioka, Frank Stratmann, Martin Gysel-Beer, Daniel P. Grosvenor, and Ken S. Carslaw
Atmos. Chem. Phys., 20, 10063–10072, https://doi.org/10.5194/acp-20-10063-2020, https://doi.org/10.5194/acp-20-10063-2020, 2020
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The amount of energy reflected back into space because of man-made particles is highly uncertain. Processes related to naturally occurring particles cause most of the uncertainty, but these processes are poorly constrained by present-day measurements. We show that measurements over the Southern Ocean, far from pollution sources, efficiently reduce climate model uncertainties. Our results pave the way to designing experiments and measurement campaigns that reduce this uncertainty even further.
Manuela van Pinxteren, Khanneh Wadinga Fomba, Nadja Triesch, Christian Stolle, Oliver Wurl, Enno Bahlmann, Xianda Gong, Jens Voigtländer, Heike Wex, Tiera-Brandy Robinson, Stefan Barthel, Sebastian Zeppenfeld, Erik Hans Hoffmann, Marie Roveretto, Chunlin Li, Benoit Grosselin, Veronique Daële, Fabian Senf, Dominik van Pinxteren, Malena Manzi, Nicolás Zabalegui, Sanja Frka, Blaženka Gašparović, Ryan Pereira, Tao Li, Liang Wen, Jiarong Li, Chao Zhu, Hui Chen, Jianmin Chen, Björn Fiedler, Wolf von Tümpling, Katie Alana Read, Shalini Punjabi, Alastair Charles Lewis, James Roland Hopkins, Lucy Jane Carpenter, Ilka Peeken, Tim Rixen, Detlef Schulz-Bull, María Eugenia Monge, Abdelwahid Mellouki, Christian George, Frank Stratmann, and Hartmut Herrmann
Atmos. Chem. Phys., 20, 6921–6951, https://doi.org/10.5194/acp-20-6921-2020, https://doi.org/10.5194/acp-20-6921-2020, 2020
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An introduction to a comprehensive field campaign performed at the Cape Verde Atmospheric Observatory regarding ocean–atmosphere interactions is given. Chemical, physical, biological and meteorological techniques were applied, and measurements of bulk water, the sea surface microlayer, cloud water and ambient aerosol particles took place. Oceanic compounds were found to be transferred to atmospheric aerosol and to the cloud level; however, sea spray contributions to CCN and INPs were limited.
Elise S. Droste, Karina E. Adcock, Matthew J. Ashfold, Charles Chou, Zoë Fleming, Paul J. Fraser, Lauren J. Gooch, Andrew J. Hind, Ray L. Langenfelds, Emma C. Leedham Elvidge, Norfazrin Mohd Hanif, Simon O'Doherty, David E. Oram, Chang-Feng Ou-Yang, Marios Panagi, Claire E. Reeves, William T. Sturges, and Johannes C. Laube
Atmos. Chem. Phys., 20, 4787–4807, https://doi.org/10.5194/acp-20-4787-2020, https://doi.org/10.5194/acp-20-4787-2020, 2020
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We update the tropospheric trends and emissions of six perfluorocarbon (PFC) gases, including separate isomers. Trends for these strong greenhouse gases are still increasing, but at slower rates than previously. The lack of natural sinks results in the global accumulation of 833 million metric tonnes of CO2 equivalent for these six PFCs by 2017. Modelling results indicate potential source regions and types in East Asia, but we find that many emissions are unaccounted for in emission reports.
Dennis Niedermeier, Jens Voigtländer, Silvio Schmalfuß, Daniel Busch, Jörg Schumacher, Raymond A. Shaw, and Frank Stratmann
Atmos. Meas. Tech., 13, 2015–2033, https://doi.org/10.5194/amt-13-2015-2020, https://doi.org/10.5194/amt-13-2015-2020, 2020
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In this paper, we present the new moist-air wind tunnel LACIS-T (Turbulent Leipzig Aerosol Cloud Interaction Simulator). It is used to study cloud physical processes in general and interactions between turbulence and cloud microphysical processes in particular. The operating principle of LACIS-T is explained, and the first results are depicted from deliquescence and droplet formation experiments observing clear indications on the effect of turbulence on these microphysical processes.
Xianda Gong, Heike Wex, Jens Voigtländer, Khanneh Wadinga Fomba, Kay Weinhold, Manuela van Pinxteren, Silvia Henning, Thomas Müller, Hartmut Herrmann, and Frank Stratmann
Atmos. Chem. Phys., 20, 1431–1449, https://doi.org/10.5194/acp-20-1431-2020, https://doi.org/10.5194/acp-20-1431-2020, 2020
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We characterized the aerosol particles in Cabo Verde at sea and cloud levels. We found four well-separable types of PNSDs, with the strongest differences between air masses coming from the ocean compared to from the African continent. During the strongest observed dust periods, CCN concentrations were 2.5 higher than during clean marine periods. The hygroscopicity of the particles did not vary much between different periods. Aerosol at sea level and on the mountaintop was well in agreement.
Xianda Gong, Heike Wex, Manuela van Pinxteren, Nadja Triesch, Khanneh Wadinga Fomba, Jasmin Lubitz, Christian Stolle, Tiera-Brandy Robinson, Thomas Müller, Hartmut Herrmann, and Frank Stratmann
Atmos. Chem. Phys., 20, 1451–1468, https://doi.org/10.5194/acp-20-1451-2020, https://doi.org/10.5194/acp-20-1451-2020, 2020
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In this study, we examined number concentrations of ice nucleating particles (INPs) at Cabo Verde in the oceanic sea surface microlayer and underlying seawater, in the air close to both sea level and cloud level, and in cloud water. The results show that most INPs are supermicron in size, that INP number concentrations in air fit well to those in cloud water and that sea spray aerosols at maximum contributed a small fraction of all INPs in the air at Cabo Verde.
Simonas Kecorius, Teresa Vogl, Pauli Paasonen, Janne Lampilahti, Daniel Rothenberg, Heike Wex, Sebastian Zeppenfeld, Manuela van Pinxteren, Markus Hartmann, Silvia Henning, Xianda Gong, Andre Welti, Markku Kulmala, Frank Stratmann, Hartmut Herrmann, and Alfred Wiedensohler
Atmos. Chem. Phys., 19, 14339–14364, https://doi.org/10.5194/acp-19-14339-2019, https://doi.org/10.5194/acp-19-14339-2019, 2019
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Arctic sea-ice retreat, atmospheric new particle formation (NPF), and aerosol–cloud interaction may all be linked via a positive feedback mechanism. Understanding the sources of cloud condensation nuclei (CCN) is an important piece in the Arctic amplification puzzle. We show that Arctic newly formed particles do not have to grow beyond the Aitken mode to act as CCN. This is important, because NPF occurrence in the Arctic is expected to increase, making it a significant contributor to CCN budget.
André Welti, Ulrike Lohmann, and Zamin A. Kanji
Atmos. Chem. Phys., 19, 10901–10918, https://doi.org/10.5194/acp-19-10901-2019, https://doi.org/10.5194/acp-19-10901-2019, 2019
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The ice nucleation ability of singly immersed feldspar particles in suspended water droplets relevant for ice crystal formation under mixed-phase cloud conditions is presented. The effects of particle size, crystal structure, trace metal and mineralogical composition are discussed by testing up to five different diameters in the submicron range and nine different feldspar samples at conditions relevant for ice nucleation in mixed-phase clouds.
Xianda Gong, Heike Wex, Thomas Müller, Alfred Wiedensohler, Kristina Höhler, Konrad Kandler, Nan Ma, Barbara Dietel, Thea Schiebel, Ottmar Möhler, and Frank Stratmann
Atmos. Chem. Phys., 19, 10883–10900, https://doi.org/10.5194/acp-19-10883-2019, https://doi.org/10.5194/acp-19-10883-2019, 2019
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For the diverse aerosol on Cyprus, we found the following: new particle formation can be a source of cloud condensation nuclei. Particle hygroscopicity showed that particles ~<100 nm contained mostly organic material, while larger ones were more hygroscopic. Two separate methods obtained similar concentrations of ice-nucleating particles (INP), with mostly no evidence of a local origin. Different parameterizations overestimated INP concentration in this rather polluted region.
Heike Wex, Lin Huang, Wendy Zhang, Hayley Hung, Rita Traversi, Silvia Becagli, Rebecca J. Sheesley, Claire E. Moffett, Tate E. Barrett, Rossana Bossi, Henrik Skov, Anja Hünerbein, Jasmin Lubitz, Mareike Löffler, Olivia Linke, Markus Hartmann, Paul Herenz, and Frank Stratmann
Atmos. Chem. Phys., 19, 5293–5311, https://doi.org/10.5194/acp-19-5293-2019, https://doi.org/10.5194/acp-19-5293-2019, 2019
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We found an annual cycle for ice-nucleating particles in the Arctic. These particles are important for Arctic clouds, as they can change the lifetime of clouds. We suggest that higher concentrations of these particles in summertime originate from the Arctic biosphere (both marine and terrestrial). With a warming Arctic, these concentrations may increase further, influencing aerosol–cloud interactions and therewith the observed strong warming of the Arctic.
Paul Herenz, Heike Wex, Alexander Mangold, Quentin Laffineur, Irina V. Gorodetskaya, Zoë L. Fleming, Marios Panagi, and Frank Stratmann
Atmos. Chem. Phys., 19, 275–294, https://doi.org/10.5194/acp-19-275-2019, https://doi.org/10.5194/acp-19-275-2019, 2019
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Atmospheric aerosol particles were observed in Antarctica, at the Belgian Princess Elisabeth station during three austral summers. Possible source regions for the particles were examined. Air that spent more than 90 %; of the time during 10 days over Antarctica had low and stable number concentrations, while the highest (new particle formation) and lowest (scavenging and wet deposition) concentrations were observed for air masses that were more strongly influenced by the Southern Ocean.
Paul J. DeMott, Ottmar Möhler, Daniel J. Cziczo, Naruki Hiranuma, Markus D. Petters, Sarah S. Petters, Franco Belosi, Heinz G. Bingemer, Sarah D. Brooks, Carsten Budke, Monika Burkert-Kohn, Kristen N. Collier, Anja Danielczok, Oliver Eppers, Laura Felgitsch, Sarvesh Garimella, Hinrich Grothe, Paul Herenz, Thomas C. J. Hill, Kristina Höhler, Zamin A. Kanji, Alexei Kiselev, Thomas Koop, Thomas B. Kristensen, Konstantin Krüger, Gourihar Kulkarni, Ezra J. T. Levin, Benjamin J. Murray, Alessia Nicosia, Daniel O'Sullivan, Andreas Peckhaus, Michael J. Polen, Hannah C. Price, Naama Reicher, Daniel A. Rothenberg, Yinon Rudich, Gianni Santachiara, Thea Schiebel, Jann Schrod, Teresa M. Seifried, Frank Stratmann, Ryan C. Sullivan, Kaitlyn J. Suski, Miklós Szakáll, Hans P. Taylor, Romy Ullrich, Jesus Vergara-Temprado, Robert Wagner, Thomas F. Whale, Daniel Weber, André Welti, Theodore W. Wilson, Martin J. Wolf, and Jake Zenker
Atmos. Meas. Tech., 11, 6231–6257, https://doi.org/10.5194/amt-11-6231-2018, https://doi.org/10.5194/amt-11-6231-2018, 2018
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The ability to measure ice nucleating particles is vital to quantifying their role in affecting clouds and precipitation. Methods for measuring droplet freezing were compared while co-sampling relevant particle types. Measurement correspondence was very good for ice nucleating particles of bacterial and natural soil origin, and somewhat more disparate for those of mineral origin. Results reflect recently improved capabilities and provide direction toward addressing remaining measurement issues.
Sarah Grawe, Stefanie Augustin-Bauditz, Hans-Christian Clemen, Martin Ebert, Stine Eriksen Hammer, Jasmin Lubitz, Naama Reicher, Yinon Rudich, Johannes Schneider, Robert Staacke, Frank Stratmann, André Welti, and Heike Wex
Atmos. Chem. Phys., 18, 13903–13923, https://doi.org/10.5194/acp-18-13903-2018, https://doi.org/10.5194/acp-18-13903-2018, 2018
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In this study, coal fly ash particles immersed in supercooled cloud droplets were analyzed concerning their freezing behavior. Additionally, physico-chemical particle properties (morphology, chemical composition, crystallography) were investigated. In combining both aspects, components that potentially contribute to the observed freezing behavior of the ash could be identified. Interactions at the particle-water interface, that depend on suspension time and influence freezing, are discussed.
Jens Voigtländer, Cedric Chou, Henner Bieligk, Tina Clauss, Susan Hartmann, Paul Herenz, Dennis Niedermeier, Georg Ritter, Frank Stratmann, and Zbigniew Ulanowski
Atmos. Chem. Phys., 18, 13687–13702, https://doi.org/10.5194/acp-18-13687-2018, https://doi.org/10.5194/acp-18-13687-2018, 2018
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Surface roughness of ice crystals has recently been acknowledged to strongly influence the radiative properties of cold clouds such as cirrus, but it is unclear how this roughness arises. The study investigates the origins of ice surface roughness under a variety of atmospherically relevant conditions, using a novel method to measure roughness quantitatively. It is found that faster growth leads to stronger roughness. Roughness also increases following repeated growth–sublimation cycles.
Juliane L. Fry, Steven S. Brown, Ann M. Middlebrook, Peter M. Edwards, Pedro Campuzano-Jost, Douglas A. Day, José L. Jimenez, Hannah M. Allen, Thomas B. Ryerson, Ilana Pollack, Martin Graus, Carsten Warneke, Joost A. de Gouw, Charles A. Brock, Jessica Gilman, Brian M. Lerner, William P. Dubé, Jin Liao, and André Welti
Atmos. Chem. Phys., 18, 11663–11682, https://doi.org/10.5194/acp-18-11663-2018, https://doi.org/10.5194/acp-18-11663-2018, 2018
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This paper uses measurements made during research aircraft flights through power plant smokestack emissions plumes as a natural laboratory in the field experiment. We investigated a specific source of airborne particulate matter from the combination of human-produced NOx pollutant emissions (the smokestack plumes) with isoprene emitted by naturally by trees in the southeastern United States. These field-based yields appear to be higher than those typically measured in chamber studies.
Paul Herenz, Heike Wex, Silvia Henning, Thomas Bjerring Kristensen, Florian Rubach, Anja Roth, Stephan Borrmann, Heiko Bozem, Hannes Schulz, and Frank Stratmann
Atmos. Chem. Phys., 18, 4477–4496, https://doi.org/10.5194/acp-18-4477-2018, https://doi.org/10.5194/acp-18-4477-2018, 2018
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The Arctic climate is changing much faster than other regions on Earth. Hence, it is necessary to investigate the processes that are liable for this phenomena and to document the current situation in the Arctic. Therefore, we measured the number and also the size of aerosol particles. It turned out that we captured the transition from the Arctic spring to the Arctic summer and that the according air masses show differences in particle properties. Also, the particles have a low water receptivity.
Julian Hofer, Dietrich Althausen, Sabur F. Abdullaev, Abduvosit N. Makhmudov, Bakhron I. Nazarov, Georg Schettler, Ronny Engelmann, Holger Baars, K. Wadinga Fomba, Konrad Müller, Bernd Heinold, Konrad Kandler, and Albert Ansmann
Atmos. Chem. Phys., 17, 14559–14577, https://doi.org/10.5194/acp-17-14559-2017, https://doi.org/10.5194/acp-17-14559-2017, 2017
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The Central Asian Dust Experiment provides unprecedented data on vertically resolved aerosol optical properties over Central Asia from continuous 18-month polarization Raman lidar observations in Dushanbe, Tajikistan. Central Asia is affected by climate change (e.g. glacier retreat) but in a large part missing vertically resolved aerosol measurements, which would help to better understand transport of dust and pollution aerosol across Central Asia and their influence on climate and health.
Ian Crawford, Martin W. Gallagher, Keith N. Bower, Thomas W. Choularton, Michael J. Flynn, Simon Ruske, Constantino Listowski, Neil Brough, Thomas Lachlan-Cope, Zoë L. Fleming, Virginia E. Foot, and Warren R. Stanley
Atmos. Chem. Phys., 17, 14291–14307, https://doi.org/10.5194/acp-17-14291-2017, https://doi.org/10.5194/acp-17-14291-2017, 2017
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We present the first real-time detection of bioparticles on the Antarctic continent using a novel UV-LIF technique. The high time resolution of the technique allowed us to examine the relationships between bioparticle concentrations and airmass history and local winds, which would not have been possible with conventional high-volume filter sampling techniques. We also show evidence of episodic long-range transport of pollen from coastal South America to the continent.
Sebastian J. O'Shea, Thomas W. Choularton, Michael Flynn, Keith N. Bower, Martin Gallagher, Jonathan Crosier, Paul Williams, Ian Crawford, Zoë L. Fleming, Constantino Listowski, Amélie Kirchgaessner, Russell S. Ladkin, and Thomas Lachlan-Cope
Atmos. Chem. Phys., 17, 13049–13070, https://doi.org/10.5194/acp-17-13049-2017, https://doi.org/10.5194/acp-17-13049-2017, 2017
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Few direct measurements have been made of Antarctic cloud and aerosol properties. As part of the 2015 Microphysics of Antarctic Clouds (MAC) field campaign, detailed airborne and ground-based measurements were made over the Weddell Sea and Antarctic coastal continent. This paper presents the first results from this campaign and discusses the cloud properties and processes important in this region.
Jin Liao, Charles A. Brock, Daniel M. Murphy, Donna T. Sueper, André Welti, and Ann M. Middlebrook
Atmos. Meas. Tech., 10, 3801–3820, https://doi.org/10.5194/amt-10-3801-2017, https://doi.org/10.5194/amt-10-3801-2017, 2017
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The Aerodyne aerosol mass spectrometer (AMS) has emerged as a widely used method for measuring the real-time, submicron, nonrefractory aerosol composition. A large uncertainty in accurate measurements with the AMS (the collection efficiency due to particle bounce) is evaluated in this paper using in situ measurements of particle light scattering. Current calculations of the collection efficiency reasonably predict this effect in acidic environments, resulting in more confidence for AMS results.
Monika Burkert-Kohn, Heike Wex, André Welti, Susan Hartmann, Sarah Grawe, Lisa Hellner, Paul Herenz, James D. Atkinson, Frank Stratmann, and Zamin A. Kanji
Atmos. Chem. Phys., 17, 11683–11705, https://doi.org/10.5194/acp-17-11683-2017, https://doi.org/10.5194/acp-17-11683-2017, 2017
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Several instruments can investigate properties of ice-nucleating particles (INPs), which are crucial to understanding ice cloud formation. We intercompare four online ice nucleation counters and reasonable agreement is found when the same ice nucleation mode is tested. A variable scaling factor was necessary to reconcile condensation freezing results with immersion freezing. Factors related to instrumental setup and aerosol generation are discussed to explain observed differences.
Leonid Nichman, Emma Järvinen, James Dorsey, Paul Connolly, Jonathan Duplissy, Claudia Fuchs, Karoliina Ignatius, Kamalika Sengupta, Frank Stratmann, Ottmar Möhler, Martin Schnaiter, and Martin Gallagher
Atmos. Meas. Tech., 10, 3231–3248, https://doi.org/10.5194/amt-10-3231-2017, https://doi.org/10.5194/amt-10-3231-2017, 2017
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Optical probes are frequently used for the detection of cloud particles. The detected microphysical properties may affect particle growth and accretion mechanisms and the light scattering properties of cirrus clouds. In the CLOUD chamber study at CERN, we compared four optical measurement techniques. We show that shape derivation alone is not sufficient to determine the phase of the small cloud particles. None of the instruments were able to unambiguously determine the phase of small particles.
Georgios Tsagkogeorgas, Pontus Roldin, Jonathan Duplissy, Linda Rondo, Jasmin Tröstl, Jay G. Slowik, Sebastian Ehrhart, Alessandro Franchin, Andreas Kürten, Antonio Amorim, Federico Bianchi, Jasper Kirkby, Tuukka Petäjä, Urs Baltensperger, Michael Boy, Joachim Curtius, Richard C. Flagan, Markku Kulmala, Neil M. Donahue, and Frank Stratmann
Atmos. Chem. Phys., 17, 8923–8938, https://doi.org/10.5194/acp-17-8923-2017, https://doi.org/10.5194/acp-17-8923-2017, 2017
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The H2SO4 vapour pressure plays key role in Earth's and Venus' atmospheres. In regions where RH is low and stabilising bases are scarce, H2SO4 can evaporate from particles; however the H2SO4 vapour pressure at low RH is uncertain. To address this, we measured H2SO4 evaporation versus T and RH in the CLOUD chamber and constrained the equilibrium constants for dissociation and dehydration of H2SO4. This study is important for nucleation, particle growth and H2SO4 formation occurring in atmosphere.
Luisa Ickes, André Welti, and Ulrike Lohmann
Atmos. Chem. Phys., 17, 1713–1739, https://doi.org/10.5194/acp-17-1713-2017, https://doi.org/10.5194/acp-17-1713-2017, 2017
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The goal of this study is to find a parameterization scheme for general circulation models to describe immersion freezing with the ability to shift and adjust the slope of the freezing curve compared to homogeneous freezing to match experimental data. We investigated how accurate different formulations of classical nucleation theory reproduce measured immersion freezing curves for different mineral dust types.
Yvonne Boose, André Welti, James Atkinson, Fabiola Ramelli, Anja Danielczok, Heinz G. Bingemer, Michael Plötze, Berko Sierau, Zamin A. Kanji, and Ulrike Lohmann
Atmos. Chem. Phys., 16, 15075–15095, https://doi.org/10.5194/acp-16-15075-2016, https://doi.org/10.5194/acp-16-15075-2016, 2016
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We compare the immersion freezing behavior of four airborne to 11 surface-collected dust samples to investigate the role of different minerals for atmospheric ice nucleation on desert dust. We find that present K-feldspars dominate at T > 253 K, while quartz does at colder temperatures, and surface-collected dust samples are not necessarily representative for airborne dust. For improved ice cloud prediction, modeling of quartz and feldspar emission and transport are key.
Ying Chen, Yafang Cheng, Nan Ma, Ralf Wolke, Stephan Nordmann, Stephanie Schüttauf, Liang Ran, Birgit Wehner, Wolfram Birmili, Hugo A. C. Denier van der Gon, Qing Mu, Stefan Barthel, Gerald Spindler, Bastian Stieger, Konrad Müller, Guang-Jie Zheng, Ulrich Pöschl, Hang Su, and Alfred Wiedensohler
Atmos. Chem. Phys., 16, 12081–12097, https://doi.org/10.5194/acp-16-12081-2016, https://doi.org/10.5194/acp-16-12081-2016, 2016
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Sea salt aerosol (SSA) is important for primary and secondary aerosols on a global scale. During 10–20 September 2013, the SSA mass concentration was overestimated by a factor of 8–20 over central Europe by WRF-Chem model, stem from the uncertainty of its emission scheme. This could facilitate the coarse-mode nitrate formation (~ 140 % but inhibit the fine-mode nitrate formation (~−20 %). A special long-range transport mechanism could broaden this influence of SSA to a larger downwind region.
Baban Nagare, Claudia Marcolli, André Welti, Olaf Stetzer, and Ulrike Lohmann
Atmos. Chem. Phys., 16, 8899–8914, https://doi.org/10.5194/acp-16-8899-2016, https://doi.org/10.5194/acp-16-8899-2016, 2016
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The relative importance of contact freezing and immersion freezing at mixed-phase cloud temperatures is the subject of debate. We performed experiments using continuous-flow diffusion chambers to compare the freezing efficiency of ice-nucleating particles for both these nucleation modes. Silver iodide, kaolinite and Arizona Test Dust were used as ice-nucleating particles. We could not confirm the dominance of contact freezing over immersion freezing for our experimental conditions.
Claudia Marcolli, Baban Nagare, André Welti, and Ulrike Lohmann
Atmos. Chem. Phys., 16, 8915–8937, https://doi.org/10.5194/acp-16-8915-2016, https://doi.org/10.5194/acp-16-8915-2016, 2016
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Silver iodide is one of the best-investigated ice nuclei. It has relevance for the atmosphere since it is used for glaciogenic cloud seeding. Nevertheless, many open questions remain. This paper gives an overview of silver iodide as an ice nucleus and tries to identify the factors that influence the ice nucleation ability of silver iodide.
Nan Ma, Chunsheng Zhao, Jiangchuan Tao, Zhijun Wu, Simonas Kecorius, Zhibin Wang, Johannes Größ, Hongjian Liu, Yuxuan Bian, Ye Kuang, Monique Teich, Gerald Spindler, Konrad Müller, Dominik van Pinxteren, Hartmut Herrmann, Min Hu, and Alfred Wiedensohler
Atmos. Chem. Phys., 16, 8593–8607, https://doi.org/10.5194/acp-16-8593-2016, https://doi.org/10.5194/acp-16-8593-2016, 2016
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New particle formation (NPF) is one of main sources of cloud condensation nuclei (CCN) in the atmosphere. Based on in situ measurements, we found that CCN activity of newly formed particles largely differs in different NPF events. It is therefore difficult to find a simple parameterization of CCN activity for NPF events. Using a fixed size-resolved activation ratio curve or critical diameter is very likely to result in large biases up to 50 % in the calculated NCCN during NPF events.
Sarvesh Garimella, Thomas Bjerring Kristensen, Karolina Ignatius, Andre Welti, Jens Voigtländer, Gourihar R. Kulkarni, Frank Sagan, Gregory Lee Kok, James Dorsey, Leonid Nichman, Daniel Alexander Rothenberg, Michael Rösch, Amélie Catharina Ruth Kirchgäßner, Russell Ladkin, Heike Wex, Theodore W. Wilson, Luis Antonio Ladino, Jon P. D. Abbatt, Olaf Stetzer, Ulrike Lohmann, Frank Stratmann, and Daniel James Cziczo
Atmos. Meas. Tech., 9, 2781–2795, https://doi.org/10.5194/amt-9-2781-2016, https://doi.org/10.5194/amt-9-2781-2016, 2016
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The SPectrometer for Ice Nuclei (SPIN) is a commercially available ice nuclei counter manufactured by Droplet Measurement Technologies in Boulder, CO. This study characterizes the SPIN chamber, reporting data from laboratory measurements and quantifying uncertainties. Overall, we report that the SPIN is able to reproduce previous CFDC ice nucleation measurements.
Charles A. Brock, Nicholas L. Wagner, Bruce E. Anderson, Alexis R. Attwood, Andreas Beyersdorf, Pedro Campuzano-Jost, Annmarie G. Carlton, Douglas A. Day, Glenn S. Diskin, Timothy D. Gordon, Jose L. Jimenez, Daniel A. Lack, Jin Liao, Milos Z. Markovic, Ann M. Middlebrook, Nga L. Ng, Anne E. Perring, Matthews S. Richardson, Joshua P. Schwarz, Rebecca A. Washenfelder, Andre Welti, Lu Xu, Luke D. Ziemba, and Daniel M. Murphy
Atmos. Chem. Phys., 16, 4987–5007, https://doi.org/10.5194/acp-16-4987-2016, https://doi.org/10.5194/acp-16-4987-2016, 2016
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Microscopic pollution particles make the atmosphere look hazy and also cool the earth by sending sunlight back to space. When the air is moist, these particles swell with water and scatter even more sunlight. We showed that particles formed from organic material – which dominates particulate pollution in the southeastern U.S. – does not take up water very effectively, toward the low end of most previous studies. We also found a better way to mathematically describe this swelling process.
Charles A. Brock, Nicholas L. Wagner, Bruce E. Anderson, Andreas Beyersdorf, Pedro Campuzano-Jost, Douglas A. Day, Glenn S. Diskin, Timothy D. Gordon, Jose L. Jimenez, Daniel A. Lack, Jin Liao, Milos Z. Markovic, Ann M. Middlebrook, Anne E. Perring, Matthews S. Richardson, Joshua P. Schwarz, Andre Welti, Luke D. Ziemba, and Daniel M. Murphy
Atmos. Chem. Phys., 16, 5009–5019, https://doi.org/10.5194/acp-16-5009-2016, https://doi.org/10.5194/acp-16-5009-2016, 2016
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Two research aircraft made dozens of vertical profiles over rural areas in the southeastern US in summer 2013. These measurements show that, in addition to how much pollution was present and how moist the atmosphere was, the size of the pollutant particles affected how much sunlight was reflected back to space. These measurements will help climate modelers determine which characteristics of pollution are important to predict with accuracy.
Dominik van Pinxteren, Khanneh Wadinga Fomba, Stephan Mertes, Konrad Müller, Gerald Spindler, Johannes Schneider, Taehyoung Lee, Jeffrey L. Collett, and Hartmut Herrmann
Atmos. Chem. Phys., 16, 3185–3205, https://doi.org/10.5194/acp-16-3185-2016, https://doi.org/10.5194/acp-16-3185-2016, 2016
P. S. Kim, D. J. Jacob, J. A. Fisher, K. Travis, K. Yu, L. Zhu, R. M. Yantosca, M. P. Sulprizio, J. L. Jimenez, P. Campuzano-Jost, K. D. Froyd, J. Liao, J. W. Hair, M. A. Fenn, C. F. Butler, N. L. Wagner, T. D. Gordon, A. Welti, P. O. Wennberg, J. D. Crounse, J. M. St. Clair, A. P. Teng, D. B. Millet, J. P. Schwarz, M. Z. Markovic, and A. E. Perring
Atmos. Chem. Phys., 15, 10411–10433, https://doi.org/10.5194/acp-15-10411-2015, https://doi.org/10.5194/acp-15-10411-2015, 2015
K. W. Fomba, D. van Pinxteren, K. Müller, Y. Iinuma, T. Lee, J. L. Collett Jr., and H. Herrmann
Atmos. Chem. Phys., 15, 8751–8765, https://doi.org/10.5194/acp-15-8751-2015, https://doi.org/10.5194/acp-15-8751-2015, 2015
N. L. Wagner, C. A. Brock, W. M. Angevine, A. Beyersdorf, P. Campuzano-Jost, D. Day, J. A. de Gouw, G. S. Diskin, T. D. Gordon, M. G. Graus, J. S. Holloway, G. Huey, J. L. Jimenez, D. A. Lack, J. Liao, X. Liu, M. Z. Markovic, A. M. Middlebrook, T. Mikoviny, J. Peischl, A. E. Perring, M. S. Richardson, T. B. Ryerson, J. P. Schwarz, C. Warneke, A. Welti, A. Wisthaler, L. D. Ziemba, and D. M. Murphy
Atmos. Chem. Phys., 15, 7085–7102, https://doi.org/10.5194/acp-15-7085-2015, https://doi.org/10.5194/acp-15-7085-2015, 2015
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This paper investigates the summertime vertical profile of aerosol over the southeastern US using in situ measurements collected from aircraft. We use a vertical mixing model and measurements of CO to predict the vertical profile of aerosol that we would expect from vertical mixing alone and compare with the observed aerosol profile. We found a modest enhancement of aerosol in the cloudy transition layer during shallow cumulus convection and attribute the enhancement to local aerosol formation.
N. Hiranuma, S. Augustin-Bauditz, H. Bingemer, C. Budke, J. Curtius, A. Danielczok, K. Diehl, K. Dreischmeier, M. Ebert, F. Frank, N. Hoffmann, K. Kandler, A. Kiselev, T. Koop, T. Leisner, O. Möhler, B. Nillius, A. Peckhaus, D. Rose, S. Weinbruch, H. Wex, Y. Boose, P. J. DeMott, J. D. Hader, T. C. J. Hill, Z. A. Kanji, G. Kulkarni, E. J. T. Levin, C. S. McCluskey, M. Murakami, B. J. Murray, D. Niedermeier, M. D. Petters, D. O'Sullivan, A. Saito, G. P. Schill, T. Tajiri, M. A. Tolbert, A. Welti, T. F. Whale, T. P. Wright, and K. Yamashita
Atmos. Chem. Phys., 15, 2489–2518, https://doi.org/10.5194/acp-15-2489-2015, https://doi.org/10.5194/acp-15-2489-2015, 2015
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Seventeen ice nucleation measurement techniques contributed to investigate the immersion freezing behavior of illite NX. All data showed a similar temperature trend, but the measured ice nucleation activity was on average smaller for the wet suspended samples and higher for the dry-dispersed aerosol samples at high temperatures. A continued investigation and collaboration is necessary to obtain further insights into consistency or diversity of ice nucleation measurements.
K. W. Fomba, K. Müller, D. van Pinxteren, L. Poulain, M. van Pinxteren, and H. Herrmann
Atmos. Chem. Phys., 14, 8883–8904, https://doi.org/10.5194/acp-14-8883-2014, https://doi.org/10.5194/acp-14-8883-2014, 2014
S. Scheinhardt, D. van Pinxteren, K. Müller, G. Spindler, and H. Herrmann
Atmos. Chem. Phys., 14, 4531–4538, https://doi.org/10.5194/acp-14-4531-2014, https://doi.org/10.5194/acp-14-4531-2014, 2014
N. Niedermeier, A. Held, T. Müller, B. Heinold, K. Schepanski, I. Tegen, K. Kandler, M. Ebert, S. Weinbruch, K. Read, J. Lee, K. W. Fomba, K. Müller, H. Herrmann, and A. Wiedensohler
Atmos. Chem. Phys., 14, 2245–2266, https://doi.org/10.5194/acp-14-2245-2014, https://doi.org/10.5194/acp-14-2245-2014, 2014
Z. A. Kanji, A. Welti, C. Chou, O. Stetzer, and U. Lohmann
Atmos. Chem. Phys., 13, 9097–9118, https://doi.org/10.5194/acp-13-9097-2013, https://doi.org/10.5194/acp-13-9097-2013, 2013
Z. J. Wu, L. Poulain, S. Henning, K. Dieckmann, W. Birmili, M. Merkel, D. van Pinxteren, G. Spindler, K. Müller, F. Stratmann, H. Herrmann, and A. Wiedensohler
Atmos. Chem. Phys., 13, 7983–7996, https://doi.org/10.5194/acp-13-7983-2013, https://doi.org/10.5194/acp-13-7983-2013, 2013
K. W. Fomba, K. Müller, D. van Pinxteren, and H. Herrmann
Atmos. Chem. Phys., 13, 4801–4814, https://doi.org/10.5194/acp-13-4801-2013, https://doi.org/10.5194/acp-13-4801-2013, 2013
Related subject area
Subject: Clouds and Precipitation | Research Activity: Field Measurements | Altitude Range: Troposphere | Science Focus: Physics (physical properties and processes)
Light scattering and microphysical properties of atmospheric bullet rosette ice crystals
Moisture budget estimates derived from airborne observations in an Arctic atmospheric river during its dissipation
Aerosol–cloud interactions in cirrus clouds based on global-scale airborne observations and machine learning models
In-cloud characteristics observed in northeastern and midwestern US non-orographic winter storms with implications for ice particle mass growth and residence time
Vertical profiles of liquid water content in fog layers during the SOFOG3D experiment
Quantified ice-nucleating ability of AgI-containing seeding particles in natural clouds
Measurement report: A survey of meteorological and cloud properties during ACTIVATE’s postfrontal flights and their suitability for Lagrangian case studies
Quantifying the impact of solar zenith angle, cloud optical thickness, and surface albedo on the solar radiative effect of Arctic low-level clouds over open ocean and sea ice
Characterization of fog microphysics and their relationships with visibility at a mountain site in China
Quantifying ice crystal growth rates in natural clouds from glaciogenic cloud seeding experiments
Measurement report: Microphysical and optical characteristic of radiation fog – a study using in-situ, remote sensing, and balloon techniques
Hunting for gravity waves in non-orographic winter storms using 3+ years of regional surface air pressure network and radar observations
Theoretical framework for measuring cloud effective supersaturation fluctuations with an advanced optical system
Airborne observations of cloud properties during their evolution from organized streets to isotropic cloud structures along an Arctic cold air outbreak
Synthesis of surface snowfall rates and radar-observed storm structures in 10+ years of Northeast US winter storms
Investigating the role of typhoon-induced waves and stratospheric hydration in the formation of tropopause cirrus clouds observed during the 2017 Asian monsoon
How does riming influence the observed spatial variability of ice water in mixed-phase clouds?
Microphysical view of the development and ice production of mid-latitude stratiform clouds with embedded convection during an extratropical cyclone
Clouds and precipitation in the initial phase of marine cold-air outbreaks as observed by airborne remote sensing
Estimating the snow density using collocated Parsivel and Micro-Rain Radar measurements: a preliminary study from ICE-POP 2017/2018
Technical note: On the ice microphysics of isolated thunderstorms and non-thunderstorms in southern China – a radar polarimetric perspective
Distinctive aerosol–cloud–precipitation interactions in marine boundary layer clouds from the ACE-ENA and SOCRATES aircraft field campaigns
Drivers of droplet formation in east Mediterranean orographic clouds
Observed impacts of aerosol concentration on maritime tropical convection within constrained environments using airborne radiometer, radar, lidar, and dropsondes
Causal Analysis of Aerosol Impacts on Isolated Deep Convection: Findings from TRACER
Observability of moisture transport divergence in Arctic atmospheric rivers by dropsondes
Elucidating the boundary layer turbulence dissipation rate using high-resolution measurements from a radar wind profiler network over the Tibetan Plateau
Environmental controls on isolated convection during the Amazonian wet season
Isotopic composition of convective rainfall in the inland tropics of Brazil
Measurement report: Cloud and environmental properties associated with aggregated shallow marine cumulus and cumulus congestus
Lifecycle of updrafts and mass flux in isolated deep convection over the Amazon rainforest: insights from cell tracking
Thermodynamic and cloud evolution in a cold-air outbreak during HALO-(AC)3: quasi-Lagrangian observations compared to the ERA5 and CARRA reanalyses
Powering aircraft with 100 % sustainable aviation fuel reduces ice crystals in contrails
Supercooled liquid water clouds observed over Dome C, Antarctica: temperature sensitivity and cloud radiative forcing
Role of thermodynamic and turbulence processes on the fog life cycle during SOFOG3D experiment
Characterizing the near-global cloud vertical structures over land using high-resolution radiosonde measurements
Differences in microphysical properties of cirrus at high and mid-latitudes
Sub-cloud rain evaporation in the North Atlantic winter trade winds derived by pairing isotopic data with a bin-resolved microphysical model
Overview and statistical analysis of boundary layer clouds and precipitation over the western North Atlantic Ocean
A set of methods to evaluate the below-cloud evaporation effect on local precipitation isotopic composition: a case study for Xi'an, China
Earth-system-model evaluation of cloud and precipitation occurrence for supercooled and warm clouds over the Southern Ocean's Macquarie Island
Pollution slightly enhances atmospheric cooling by low-level clouds in tropical West Africa
Investigating an indirect aviation effect on mid-latitude cirrus clouds – linking lidar-derived optical properties to in situ measurements
Investigating the vertical extent and short-wave radiative effects of the ice phase in Arctic summertime low-level clouds
Microphysical and thermodynamic phase analyses of Arctic low-level clouds measured above the sea ice and the open ocean in spring and summer
Aircraft observations of gravity wave activity and turbulence in the tropical tropopause layer: prevalence, influence on cirrus clouds, and comparison with global storm-resolving models
Influence of air mass origin on microphysical properties of low-level clouds in a subarctic environment
Sensitivity of convectively driven tropical tropopause cirrus properties to ice habits in high-resolution simulations
Upper-tropospheric slightly ice-subsaturated regions: frequency of occurrence and statistical evidence for the appearance of contrail cirrus
Examination of aerosol indirect effects during cirrus cloud evolution
Shawn W. Wagner, Martin Schnaiter, Guanglang Xu, Franziska Rogge, and Emma Järvinen
Atmos. Chem. Phys., 25, 8785–8804, https://doi.org/10.5194/acp-25-8785-2025, https://doi.org/10.5194/acp-25-8785-2025, 2025
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Understanding the interaction between cirrus clouds and solar radiation is critical for modeling the Earth's climate. A common crystal type found in cirrus clouds is the bullet rosette. Here, atmospheric bullet rosettes measured from jet aircraft are analyzed for their morphological and radiative properties. Atmospheric bullet rosettes are found to be more morphologically complex than previously assumed. This complexity has a significant impact on their radiative properties.
Henning Dorff, Florian Ewald, Heike Konow, Mario Mech, Davide Ori, Vera Schemann, Andreas Walbröl, Manfred Wendisch, and Felix Ament
Atmos. Chem. Phys., 25, 8329–8354, https://doi.org/10.5194/acp-25-8329-2025, https://doi.org/10.5194/acp-25-8329-2025, 2025
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Using observations of an Arctic atmospheric river (AR) from a long-range research aircraft, we analyse how moisture transported into the Arctic by the AR is transformed and how it interacts with the Arctic environment. The moisture transport divergence is the main driver of local moisture change over time. Surface precipitation and evaporation are rather weak when averaged over extended AR sectors, although considerable heterogeneity of precipitation within the AR is observed.
Derek Ngo, Minghui Diao, Ryan J. Patnaude, Sarah Woods, and Glenn Diskin
Atmos. Chem. Phys., 25, 7007–7036, https://doi.org/10.5194/acp-25-7007-2025, https://doi.org/10.5194/acp-25-7007-2025, 2025
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Key controlling factors of cirrus clouds were individually quantified using machine learning models based on global-scale in situ observations from 12 campaigns at 67° S–87° N. Relative humidity shows much larger effects on cirrus occurrences and ice water content (IWC) fluctuations than vertical velocity. Aerosol–cloud interactions are seen for both large and small aerosols, with higher IWC and ice crystal number concentration under higher aerosol concentrations. Large aerosols are more impactful than small aerosols.
Luke R. Allen, Sandra E. Yuter, Declan M. Crowe, Matthew A. Miller, and K. Lee Thornhill
Atmos. Chem. Phys., 25, 6679–6701, https://doi.org/10.5194/acp-25-6679-2025, https://doi.org/10.5194/acp-25-6679-2025, 2025
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We analyzed in-cloud characteristics using in situ measurements from 42 research flights across two field campaigns into non-orographic, non-lake-effect winter storms. Much of the storm volume contains weak vertical motions (a few centimeters per second), and most updrafts ≥ 0.5 m s-1 are small (< 1 km). Within 2 km of cloud radar echo top, stronger vertical motions and conditions for ice particle growth are more common. Overturning air motions near cloud top appear important for the production of snow particles.
Théophane Costabloz, Frédéric Burnet, Christine Lac, Pauline Martinet, Julien Delanoë, Susana Jorquera, and Maroua Fathalli
Atmos. Chem. Phys., 25, 6539–6573, https://doi.org/10.5194/acp-25-6539-2025, https://doi.org/10.5194/acp-25-6539-2025, 2025
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This study documents vertical profiles of liquid water content (LWC) in fogs from in situ measurements collected during the SOFOG3D field campaign in 2019–2020. The analysis of 140 vertical profiles reveals a reverse trend in LWC, maximum values at ground decreasing with height, during stable conditions in optically thin fogs, evolving towards quasi-adiabatic characteristics when fogs become thick. These results offer new perspectives for better constraining fog numerical simulations.
Anna J. Miller, Christopher Fuchs, Fabiola Ramelli, Huiying Zhang, Nadja Omanovic, Robert Spirig, Claudia Marcolli, Zamin A. Kanji, Ulrike Lohmann, and Jan Henneberger
Atmos. Chem. Phys., 25, 5387–5407, https://doi.org/10.5194/acp-25-5387-2025, https://doi.org/10.5194/acp-25-5387-2025, 2025
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We analyzed the ability of silver iodide particles (a commonly used cloud-seeding agent) to form ice crystals in naturally occurring liquid clouds at −5 to −8 °C and found that only ≈ 0.1 %−1 % of particles nucleate ice, with a negative dependence on temperature. By contextualizing our results with previous laboratory studies, we help to bridge the gap between laboratory and field experiments, which also helps to inform future cloud-seeding projects.
Florian Tornow, Ann Fridlind, George Tselioudis, Brian Cairns, Andrew Ackerman, Seethala Chellappan, David Painemal, Paquita Zuidema, Christiane Voigt, Simon Kirschler, and Armin Sorooshian
Atmos. Chem. Phys., 25, 5053–5074, https://doi.org/10.5194/acp-25-5053-2025, https://doi.org/10.5194/acp-25-5053-2025, 2025
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The recent NASA campaign ACTIVATE (Aerosol Cloud meTeorology Interactions oVer the western ATlantic Experiment) performed 71 tandem flights in mid-latitude marine cold-air outbreaks off the US eastern seaboard. We provide meteorological and cloud transition stage context, allowing us to identify days that are most suitable for Lagrangian modeling and analysis. Surveyed cloud properties show signatures of cloud microphysical processes, such as cloud-top entrainment and secondary ice formation.
Sebastian Becker, André Ehrlich, Michael Schäfer, and Manfred Wendisch
EGUsphere, https://doi.org/10.5194/egusphere-2025-1210, https://doi.org/10.5194/egusphere-2025-1210, 2025
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Clouds interact with solar radiation and can alter the surface temperature. The strength of this cloud impact is driven by cloud properties as well as solar elevation and surface reflection. Since these dependences are poorly represented in climate models, cloud, surface, and radiation observations are used to quantify the contributions of the drivers in the Arctic. It is shown that the weaker surface reflection dominates the stronger cooling effect of clouds over open ocean compared to sea ice.
Quan Liu, Xiaojing Shen, Junying Sun, Yangmei Zhang, Bing Qi, Qianli Ma, Lujie Han, Honghui Xu, Xinyao Hu, Jiayuan Lu, Shuo Liu, Aoyuan Yu, Linlin Liang, Qian Gao, Hong Wang, Huizheng Che, and Xiaoye Zhang
Atmos. Chem. Phys., 25, 3253–3267, https://doi.org/10.5194/acp-25-3253-2025, https://doi.org/10.5194/acp-25-3253-2025, 2025
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Through simultaneous measurements of aerosol particles and fog droplets, the evolution of droplets size distribution during the eight observed fog events was investigated. The results showed that the concentration and size distribution of pre-fog aerosol had significant impacts on fog microphysical characteristics. The extinction of fog interstitial particles played an important role in visibility degradation for light fogs, especially in polluted regions.
Christopher Fuchs, Fabiola Ramelli, Anna J. Miller, Nadja Omanovic, Robert Spirig, Huiying Zhang, Patric Seifert, Kevin Ohneiser, Ulrike Lohmann, and Jan Henneberger
EGUsphere, https://doi.org/10.5194/egusphere-2025-688, https://doi.org/10.5194/egusphere-2025-688, 2025
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We quantify diffusional ice crystal growth in natural clouds using cloud seeding experiments. We report growth rates for 14 experiments between -5.1°C and -8.3°C and observe strong variations depending on the cloud characteristics. Comparing our growth rates to laboratory data, we found similar temperature-dependent trends, but the laboratory rates are higher. This data fills the gap in quantitative in situ observation of ice crystal growth, helping to validate models and laboratory experiments.
Katarzyna Nurowska, Przemysław Makuch, and Krzysztof M. Markowicz
EGUsphere, https://doi.org/10.5194/egusphere-2024-4074, https://doi.org/10.5194/egusphere-2024-4074, 2025
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This study explores the properties of radiation fog in Southeastern Poland, focusing on how droplets and water content vary with height. Data from three September 2023 fog events show that larger droplets form near the ground, while fog dissipates from both top and bottom. Key findings include average droplet sizes, water content, and how fog impacts radiation. The results improve understanding of fog behavior and its environmental effects.
Luke R. Allen, Sandra E. Yuter, Matthew A. Miller, and Laura M. Tomkins
Atmos. Chem. Phys., 25, 1765–1790, https://doi.org/10.5194/acp-25-1765-2025, https://doi.org/10.5194/acp-25-1765-2025, 2025
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Atmospheric gravity waves (GWs) are air oscillations in which buoyancy is the restoring force, and they may enhance precipitation under certain conditions. We used 3+ seasons of pressure data to identify GWs with wavelengths ≤ 170 km in the Toronto and New York metropolitan areas in the context of snow storms. We found only six GW events during snow storms, suggesting that GWs on those scales are uncommon at the two locations during snow storms and, thus, do not often enhance snowfall.
Ye Kuang, Jiangchuan Tao, Hanbing Xu, Li Liu, Pengfei Liu, Wanyun Xu, Weiqi Xu, Yele Sun, and Chunsheng Zhao
Atmos. Chem. Phys., 25, 1163–1174, https://doi.org/10.5194/acp-25-1163-2025, https://doi.org/10.5194/acp-25-1163-2025, 2025
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This study presents a novel optical framework to measure supersaturation, a fundamental parameter in cloud physics, by observing the scattering properties of particles that have or have not grown into cloud droplets. The technique offers high-resolution measurements, capturing essential fluctuations in supersaturation necessary for understanding cloud physics.
Marcus Klingebiel, André Ehrlich, Micha Gryschka, Nils Risse, Nina Maherndl, Imke Schirmacher, Sophie Rosenburg, Sabine Hörnig, Manuel Moser, Evelyn Jäkel, Michael Schäfer, Hartwig Deneke, Mario Mech, Christiane Voigt, and Manfred Wendisch
EGUsphere, https://doi.org/10.5194/egusphere-2025-201, https://doi.org/10.5194/egusphere-2025-201, 2025
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Our study is using aircraft measurements from the HALO-(𝒜𝒞)³ campaign to investigate the transition from organized Arctic cloud street structures to more scattered cloud shapes. We show that lower wind speeds cause this transition. In addition we look at the changes of the cloud coverage, the height of the clouds, the cloud particles and the radiative properties.
Laura M. Tomkins, Sandra E. Yuter, Matthew A. Miller, Mariko Oue, and Charles N. Helms
EGUsphere, https://doi.org/10.5194/egusphere-2025-6, https://doi.org/10.5194/egusphere-2025-6, 2025
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This study investigates how radar-detected snow bands relate to snowfall rates during winter storms in the northeastern U.S. Using over a decade of data, we found that snow bands are not consistently linked to heavy snowfall at the surface, as snow particles are often dispersed by wind before reaching the ground. These findings highlight limitations of using radar reflectivity for predicting snow rates and suggest focusing on radar echo duration to better understand snowfall patterns.
Amit Kumar Pandit, Jean-Paul Vernier, Thomas Duncan Fairlie, Kristopher M. Bedka, Melody A. Avery, Harish Gadhavi, Madineni Venkat Ratnam, Sanjeev Dwivedi, Kasimahanthi Amar Jyothi, Frank G. Wienhold, Holger Vömel, Hongyu Liu, Bo Zhang, Buduru Suneel Kumar, Tra Dinh, and Achuthan Jayaraman
Atmos. Chem. Phys., 24, 14209–14238, https://doi.org/10.5194/acp-24-14209-2024, https://doi.org/10.5194/acp-24-14209-2024, 2024
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This study investigates the formation mechanism of a tropopause cirrus cloud layer observed at extremely cold temperatures over Hyderabad in India during the 2017 Asian summer monsoon using balloon-borne sensors. Ice crystals smaller than 50 µm were found in this optically thin cirrus cloud layer. Combined analysis of back trajectories, satellite, and model data revealed that the formation of this layer was influenced by waves and stratospheric hydration induced by typhoon Hato.
Nina Maherndl, Manuel Moser, Imke Schirmacher, Aaron Bansemer, Johannes Lucke, Christiane Voigt, and Maximilian Maahn
Atmos. Chem. Phys., 24, 13935–13960, https://doi.org/10.5194/acp-24-13935-2024, https://doi.org/10.5194/acp-24-13935-2024, 2024
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It is not clear why ice crystals in clouds occur in clusters. Here, airborne measurements of clouds in mid-latitudes and high latitudes are used to study the spatial variability of ice. Further, we investigate the influence of riming, which occurs when liquid droplets freeze onto ice crystals. We find that riming enhances the occurrence of ice clusters. In the Arctic, riming leads to ice clustering at spatial scales of 3–5 km. This is due to updrafts and not higher amounts of liquid water.
Yuanmou Du, Dantong Liu, Delong Zhao, Mengyu Huang, Ping Tian, Dian Wen, Wei Xiao, Wei Zhou, Hui He, Baiwan Pan, Dongfei Zuo, Xiange Liu, Yingying Jing, Rong Zhang, Jiujiang Sheng, Fei Wang, Yu Huang, Yunbo Chen, and Deping Ding
Atmos. Chem. Phys., 24, 13429–13444, https://doi.org/10.5194/acp-24-13429-2024, https://doi.org/10.5194/acp-24-13429-2024, 2024
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By conducting in situ measurements, we investigated ice production processes in stratiform clouds with embedded convection over the North China Plain. The results show that the ice number concentration is strongly related to the distance to the cloud top, and the level with a larger distance to the cloud top has more graupel falling from upper levels, which promotes collision and coalescence between graupel and droplets and enhances secondary ice production.
Imke Schirmacher, Sabrina Schnitt, Marcus Klingebiel, Nina Maherndl, Benjamin Kirbus, André Ehrlich, Mario Mech, and Susanne Crewell
Atmos. Chem. Phys., 24, 12823–12842, https://doi.org/10.5194/acp-24-12823-2024, https://doi.org/10.5194/acp-24-12823-2024, 2024
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During Arctic marine cold-air outbreaks, cold air flows from sea ice over open water. Roll circulations evolve, forming cloud streets. We investigate the initial circulation and cloud development using high-resolution airborne measurements. We compute the distance an air mass traveled over water (fetch) from back trajectories. Cloud streets form at 15 km fetch, cloud cover strongly increases at around 20 km, and precipitation forms at around 30 km.
Wei-Yu Chang, Yung-Chuan Yang, Chen-Yu Hung, Kwonil Kim, Gyuwon Lee, and Ali Tokay
Atmos. Chem. Phys., 24, 11955–11979, https://doi.org/10.5194/acp-24-11955-2024, https://doi.org/10.5194/acp-24-11955-2024, 2024
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Snow density is derived by collocated Micro-Rain Radar (MRR) and Parsivel (ICE-POP 2017/2018). We apply the particle size distribution from Parsivel to a T-matrix backscattering simulation and compare with ZHH from MRR. Bulk density and bulk water fractions are derived from comparing simulated and calculated ZHH. Retrieved bulk density is validated by comparing snowfall rate measurements from Pluvio and the Precipitation Imaging Package. Snowfall rate consistency confirms the algorithm.
Chuanhong Zhao, Yijun Zhang, Dong Zheng, Haoran Li, Sai Du, Xueyan Peng, Xiantong Liu, Pengguo Zhao, Jiafeng Zheng, and Juan Shi
Atmos. Chem. Phys., 24, 11637–11651, https://doi.org/10.5194/acp-24-11637-2024, https://doi.org/10.5194/acp-24-11637-2024, 2024
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Understanding lightning activity is important for meteorology and atmospheric chemistry. However, the occurrence of lightning activity in clouds is uncertain. In this study, we quantified the difference between isolated thunderstorms and non-thunderstorms. We showed that lightning activity was more likely to occur with more graupel volume and/or riming. A deeper ZDR column was associated with lightning occurrence. This information can aid in a deeper understanding of lighting physics.
Xiaojian Zheng, Xiquan Dong, Baike Xi, Timothy Logan, and Yuan Wang
Atmos. Chem. Phys., 24, 10323–10347, https://doi.org/10.5194/acp-24-10323-2024, https://doi.org/10.5194/acp-24-10323-2024, 2024
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The marine boundary layer aerosol–cloud interactions (ACIs) are examined using in situ measurements from two aircraft campaigns over the eastern North Atlantic (ACE-ENA) and Southern Ocean (SOCRATES). The SOCRATES clouds have more and smaller cloud droplets. The ACE-ENA clouds exhibit stronger drizzle formation and growth. Results found distinctive aerosol–cloud interactions for two campaigns. The drizzle processes significantly alter sub-cloud aerosol budgets and impact the ACI assessments.
Romanos Foskinis, Ghislain Motos, Maria I. Gini, Olga Zografou, Kunfeng Gao, Stergios Vratolis, Konstantinos Granakis, Ville Vakkari, Kalliopi Violaki, Andreas Aktypis, Christos Kaltsonoudis, Zongbo Shi, Mika Komppula, Spyros N. Pandis, Konstantinos Eleftheriadis, Alexandros Papayannis, and Athanasios Nenes
Atmos. Chem. Phys., 24, 9827–9842, https://doi.org/10.5194/acp-24-9827-2024, https://doi.org/10.5194/acp-24-9827-2024, 2024
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Analysis of modeling, in situ, and remote sensing measurements reveals the microphysical state of orographic clouds and their response to aerosol from the boundary layer and free troposphere. We show that cloud response to aerosol is robust, as predicted supersaturation and cloud droplet number levels agree with those determined from in-cloud measurements. The ability to determine if clouds are velocity- or aerosol-limited allows for novel model constraints and remote sensing products.
Corey G. Amiot, Timothy J. Lang, Susan C. van den Heever, Richard A. Ferrare, Ousmane O. Sy, Lawrence D. Carey, Sundar A. Christopher, John R. Mecikalski, Sean W. Freeman, George Alexander Sokolowsky, Chris A. Hostetler, and Simone Tanelli
EGUsphere, https://doi.org/10.5194/egusphere-2024-2384, https://doi.org/10.5194/egusphere-2024-2384, 2024
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Decoupling aerosol and environmental impacts on convection is challenging. Using airborne data, we correlated microwave-frequency convective metrics with aerosol concentrations in several different environments. Medium-to-high aerosol concentrations were often strongly and positively correlated with convective intensity and frequency, especially in favorable environments based on temperature lapse rates and K-Index. Storm environment is important to consider when evaluating aerosol effects.
Dié Wang, Roni Kobrosly, Tao Zhang, Tamanna Subba, Susan van den Heever, Siddhant Gupta, and Michael Jensen
EGUsphere, https://doi.org/10.5194/egusphere-2024-2436, https://doi.org/10.5194/egusphere-2024-2436, 2024
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We use a new method to understand how tiny particles in the air, called aerosols, affect rain clouds in the Houston-Galveston area. Aerosols generally do not make these clouds grow much taller, with an average height increase of about 1 km under certain conditions. However, their effects on rainfall strength and cloud expansion are less certain. Clouds influenced by sea breezes show a stronger aerosol impact, possibly due to unaccounted factors like vertical winds in near-surface layers.
Henning Dorff, Heike Konow, Vera Schemann, and Felix Ament
Atmos. Chem. Phys., 24, 8771–8795, https://doi.org/10.5194/acp-24-8771-2024, https://doi.org/10.5194/acp-24-8771-2024, 2024
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Using synthetic dropsondes, we assess how discrete spatial sampling and temporal evolution during flight affect the accuracy of real sonde-based moisture transport divergence in Arctic atmospheric rivers (ARs). Non-instantaneous sampling during temporal AR evolution deteriorates the divergence values more than spatial undersampling. Moisture advection is the dominating factor but most sensitive to the sampling method. We suggest a minimum of seven sondes to resolve the AR divergence components.
Deli Meng, Jianping Guo, Xiaoran Guo, Yinjun Wang, Ning Li, Yuping Sun, Zhen Zhang, Na Tang, Haoran Li, Fan Zhang, Bing Tong, Hui Xu, and Tianmeng Chen
Atmos. Chem. Phys., 24, 8703–8720, https://doi.org/10.5194/acp-24-8703-2024, https://doi.org/10.5194/acp-24-8703-2024, 2024
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The turbulence in the planetary boundary layer (PBL) over the Tibetan Plateau (TP) remains unclear. Here we elucidate the vertical profile of and temporal variation in the turbulence dissipation rate in the PBL over the TP based on a radar wind profiler (RWP) network. To the best of our knowledge, this is the first time that the turbulence profile over the whole TP has been revealed. Furthermore, the possible mechanisms of clouds acting on the PBL turbulence structure are investigated.
Leandro Alex Moreira Viscardi, Giuseppe Torri, David K. Adams, and Henrique de Melo Jorge Barbosa
Atmos. Chem. Phys., 24, 8529–8548, https://doi.org/10.5194/acp-24-8529-2024, https://doi.org/10.5194/acp-24-8529-2024, 2024
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We evaluate the environmental conditions that control how clouds grow from fair weather cumulus into severe thunderstorms during the Amazonian wet season. Days with rain clouds begin with more moisture in the air and have strong convergence in the afternoon, while precipitation intensity increases with large-scale vertical velocity, moisture, and low-level wind. These results contribute to understanding how clouds form over the rainforest.
Vinicius dos Santos, Didier Gastmans, Ana María Durán-Quesada, Ricardo Sánchez-Murillo, Kazimierz Rozanski, Oliver Kracht, and Demilson de Assis Quintão
Atmos. Chem. Phys., 24, 6663–6680, https://doi.org/10.5194/acp-24-6663-2024, https://doi.org/10.5194/acp-24-6663-2024, 2024
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We present novel findings on convective rainfall, summer rain in the late afternoon, by coupling water stable isotopes, micro rain radar, and satellite data. We found the tallest clouds in the afternoon and much smaller clouds at night, resulting in differences in day–night ratios in water stable isotopes. We sampled rain and meteorological variables every 5–10 min, allowing us to evaluate the development of convective rainfall, contributing to knowledge of rainfall related to extreme events.
Ewan Crosbie, Luke D. Ziemba, Michael A. Shook, Taylor Shingler, Johnathan W. Hair, Armin Sorooshian, Richard A. Ferrare, Brian Cairns, Yonghoon Choi, Joshua DiGangi, Glenn S. Diskin, Chris Hostetler, Simon Kirschler, Richard H. Moore, David Painemal, Claire Robinson, Shane T. Seaman, K. Lee Thornhill, Christiane Voigt, and Edward Winstead
Atmos. Chem. Phys., 24, 6123–6152, https://doi.org/10.5194/acp-24-6123-2024, https://doi.org/10.5194/acp-24-6123-2024, 2024
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Marine clouds are found to clump together in regions or lines, readily discernible from satellite images of the ocean. While clustering is also a feature of deep storm clouds, we focus on smaller cloud systems associated with fair weather and brief localized showers. Two aircraft sampled the region around these shallow systems: one incorporated measurements taken within, adjacent to, and below the clouds, while the other provided a survey from above using remote sensing techniques.
Siddhant Gupta, Dié Wang, Scott E. Giangrande, Thiago S. Biscaro, and Michael P. Jensen
Atmos. Chem. Phys., 24, 4487–4510, https://doi.org/10.5194/acp-24-4487-2024, https://doi.org/10.5194/acp-24-4487-2024, 2024
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We examine the lifecycle of isolated deep convective clouds (DCCs) in the Amazon rainforest. Weather radar echoes from the DCCs are tracked to evaluate their lifecycle. The DCC size and intensity increase, reach a peak, and then decrease over the DCC lifetime. Vertical profiles of air motion and mass transport from different seasons are examined to understand the transport of energy and momentum within DCC cores and to address the deficiencies in simulating DCCs using weather and climate models.
Benjamin Kirbus, Imke Schirmacher, Marcus Klingebiel, Michael Schäfer, André Ehrlich, Nils Slättberg, Johannes Lucke, Manuel Moser, Hanno Müller, and Manfred Wendisch
Atmos. Chem. Phys., 24, 3883–3904, https://doi.org/10.5194/acp-24-3883-2024, https://doi.org/10.5194/acp-24-3883-2024, 2024
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A research aircraft is used to track the changes in air temperature, moisture, and cloud properties for air that moves from cold Arctic sea ice onto warmer oceanic waters. The measurements are compared to two reanalysis models named ERA5 and CARRA. The biggest differences are found for air temperature over the sea ice and moisture over the ocean. CARRA data are more accurate than ERA5 because they better simulate the sea ice, the transition from sea ice to open ocean, and the forming clouds.
Raphael Satoru Märkl, Christiane Voigt, Daniel Sauer, Rebecca Katharina Dischl, Stefan Kaufmann, Theresa Harlaß, Valerian Hahn, Anke Roiger, Cornelius Weiß-Rehm, Ulrike Burkhardt, Ulrich Schumann, Andreas Marsing, Monika Scheibe, Andreas Dörnbrack, Charles Renard, Maxime Gauthier, Peter Swann, Paul Madden, Darren Luff, Reetu Sallinen, Tobias Schripp, and Patrick Le Clercq
Atmos. Chem. Phys., 24, 3813–3837, https://doi.org/10.5194/acp-24-3813-2024, https://doi.org/10.5194/acp-24-3813-2024, 2024
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In situ measurements of contrails from a large passenger aircraft burning 100 % sustainable aviation fuel (SAF) show a 56 % reduction in contrail ice crystal numbers compared to conventional Jet A-1. Results from a climate model initialized with the observations suggest a significant decrease in radiative forcing from contrails. Our study confirms that future increased use of low aromatic SAF can reduce the climate impact from aviation.
Philippe Ricaud, Massimo Del Guasta, Angelo Lupi, Romain Roehrig, Eric Bazile, Pierre Durand, Jean-Luc Attié, Alessia Nicosia, and Paolo Grigioni
Atmos. Chem. Phys., 24, 613–630, https://doi.org/10.5194/acp-24-613-2024, https://doi.org/10.5194/acp-24-613-2024, 2024
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Clouds affect the Earth's climate in ways that depend on the type of cloud (solid/liquid water). From observations at Concordia (Antarctica), we show that in supercooled liquid water (liquid water for temperatures below 0°C) clouds (SLWCs), temperature and SLWC radiative forcing increase with liquid water (up to 70 W m−2). We extrapolated that the maximum SLWC radiative forcing can reach 40 W m−2 over the Antarctic Peninsula, highlighting the importance of SLWCs for global climate prediction.
Cheikh Dione, Martial Haeffelin, Frédéric Burnet, Christine Lac, Guylaine Canut, Julien Delanoë, Jean-Charles Dupont, Susana Jorquera, Pauline Martinet, Jean-François Ribaud, and Felipe Toledo
Atmos. Chem. Phys., 23, 15711–15731, https://doi.org/10.5194/acp-23-15711-2023, https://doi.org/10.5194/acp-23-15711-2023, 2023
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This paper documents the role of thermodynamics and turbulence in the fog life cycle over southwestern France. It is based on a unique dataset collected during the SOFOG3D field campaign in autumn and winter 2019–2020. The paper gives a threshold for turbulence driving the different phases of the fog life cycle and the role of advection in the night-time dissipation of fog. The results can be operationalised to nowcast fog and improve short-range forecasts in numerical weather prediction models.
Hui Xu, Jianping Guo, Bing Tong, Jinqiang Zhang, Tianmeng Chen, Xiaoran Guo, Jian Zhang, and Wenqing Chen
Atmos. Chem. Phys., 23, 15011–15038, https://doi.org/10.5194/acp-23-15011-2023, https://doi.org/10.5194/acp-23-15011-2023, 2023
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The radiative effect of cloud remains one of the largest uncertain factors in climate change, largely due to the lack of cloud vertical structure (CVS) observations. The study presents the first near-global CVS climatology using high-vertical-resolution soundings. Single-layer cloud mainly occurs over arid regions. As the number of cloud layers increases, clouds tend to have lower bases and thinner layer thicknesses. The occurrence frequency of cloud exhibits a pronounced seasonal diurnal cycle.
Elena De La Torre Castro, Tina Jurkat-Witschas, Armin Afchine, Volker Grewe, Valerian Hahn, Simon Kirschler, Martina Krämer, Johannes Lucke, Nicole Spelten, Heini Wernli, Martin Zöger, and Christiane Voigt
Atmos. Chem. Phys., 23, 13167–13189, https://doi.org/10.5194/acp-23-13167-2023, https://doi.org/10.5194/acp-23-13167-2023, 2023
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In this study, we show the differences in the microphysical properties between high-latitude (HL) cirrus and mid-latitude (ML) cirrus over the Arctic, North Atlantic, and central Europe during summer. The in situ measurements are combined with backward trajectories to investigate the influence of the region on cloud formation. We show that HL cirrus are characterized by a lower concentration of larger ice crystals when compared to ML cirrus.
Mampi Sarkar, Adriana Bailey, Peter Blossey, Simon P. de Szoeke, David Noone, Estefanía Quiñones Meléndez, Mason D. Leandro, and Patrick Y. Chuang
Atmos. Chem. Phys., 23, 12671–12690, https://doi.org/10.5194/acp-23-12671-2023, https://doi.org/10.5194/acp-23-12671-2023, 2023
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We study rain evaporation characteristics below shallow cumulus clouds over the North Atlantic Ocean by pairing isotope observations with a microphysical model. The modeled fraction of rain mass that evaporates below the cloud strongly depends on the raindrop size and distribution width. Moreover, the higher the rain mass fraction evaporated, the greater the change in deuterium excess. In this way, rain evaporation could be studied independently using only isotope and microphysical observations.
Simon Kirschler, Christiane Voigt, Bruce E. Anderson, Gao Chen, Ewan C. Crosbie, Richard A. Ferrare, Valerian Hahn, Johnathan W. Hair, Stefan Kaufmann, Richard H. Moore, David Painemal, Claire E. Robinson, Kevin J. Sanchez, Amy J. Scarino, Taylor J. Shingler, Michael A. Shook, Kenneth L. Thornhill, Edward L. Winstead, Luke D. Ziemba, and Armin Sorooshian
Atmos. Chem. Phys., 23, 10731–10750, https://doi.org/10.5194/acp-23-10731-2023, https://doi.org/10.5194/acp-23-10731-2023, 2023
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In this study we present an overview of liquid and mixed-phase clouds and precipitation in the marine boundary layer over the western North Atlantic Ocean. We compare microphysical properties of pure liquid clouds to mixed-phase clouds and show that the initiation of the ice phase in mixed-phase clouds promotes precipitation. The observational data presented in this study are well suited for investigating the processes that give rise to liquid and mixed-phase clouds, ice, and precipitation.
Meng Xing, Weiguo Liu, Jing Hu, and Zheng Wang
Atmos. Chem. Phys., 23, 9123–9136, https://doi.org/10.5194/acp-23-9123-2023, https://doi.org/10.5194/acp-23-9123-2023, 2023
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The below-cloud evaporation effect (BCE) on precipitation largely impacts the final isotopic composition. However, determining the BCE effect remains poorly constrained. Our work used a ΔdΔδ diagram to differentiate the below-cloud processes. Moreover, by comparing two different computing methods, we considered that both methods are suitable for evaluation the BCE, except for snowfall events. Overall, our work compiled a set of effective methods to evaluate the BCE effect.
McKenna W. Stanford, Ann M. Fridlind, Israel Silber, Andrew S. Ackerman, Greg Cesana, Johannes Mülmenstädt, Alain Protat, Simon Alexander, and Adrian McDonald
Atmos. Chem. Phys., 23, 9037–9069, https://doi.org/10.5194/acp-23-9037-2023, https://doi.org/10.5194/acp-23-9037-2023, 2023
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Clouds play an important role in the Earth’s climate system as they modulate the amount of radiation that either reaches the surface or is reflected back to space. This study demonstrates an approach to robustly evaluate surface-based observations against a large-scale model. We find that the large-scale model precipitates too infrequently relative to observations, contrary to literature documentation suggesting otherwise based on satellite measurements.
Valerian Hahn, Ralf Meerkötter, Christiane Voigt, Sonja Gisinger, Daniel Sauer, Valéry Catoire, Volker Dreiling, Hugh Coe, Cyrille Flamant, Stefan Kaufmann, Jonas Kleine, Peter Knippertz, Manuel Moser, Philip Rosenberg, Hans Schlager, Alfons Schwarzenboeck, and Jonathan Taylor
Atmos. Chem. Phys., 23, 8515–8530, https://doi.org/10.5194/acp-23-8515-2023, https://doi.org/10.5194/acp-23-8515-2023, 2023
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During the DACCIWA campaign in West Africa, we found a 35 % increase in the cloud droplet concentration that formed in a polluted compared with a less polluted environment and a decrease of 17 % in effective droplet diameter. Radiative transfer simulations, based on the measured cloud properties, reveal that these low-level polluted clouds radiate only 2.6 % more energy back to space, compared with a less polluted cloud. The corresponding additional decrease in temperature is rather small.
Silke Groß, Tina Jurkat-Witschas, Qiang Li, Martin Wirth, Benedikt Urbanek, Martina Krämer, Ralf Weigel, and Christiane Voigt
Atmos. Chem. Phys., 23, 8369–8381, https://doi.org/10.5194/acp-23-8369-2023, https://doi.org/10.5194/acp-23-8369-2023, 2023
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Aviation-emitted aerosol can have an impact on cirrus clouds. We present optical and microphysical properties of mid-latitude cirrus clouds which were formed under the influence of aviation-emitted aerosol or which were formed under rather pristine conditions. We find that cirrus clouds affected by aviation-emitted aerosol show larger values of the particle linear depolarization ratio, larger mean effective ice particle diameters and decreased ice particle number concentrations.
Emma Järvinen, Franziska Nehlert, Guanglang Xu, Fritz Waitz, Guillaume Mioche, Regis Dupuy, Olivier Jourdan, and Martin Schnaiter
Atmos. Chem. Phys., 23, 7611–7633, https://doi.org/10.5194/acp-23-7611-2023, https://doi.org/10.5194/acp-23-7611-2023, 2023
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The Arctic is warming faster than other regions. Arctic low-level mixed-phase clouds, where ice crystals and liquid droplets co-exist, are thought to have an important role in Arctic warming. Here we show airborne measurements of vertical distribution of liquid and ice particles and their relative abundance. Ice particles are found in relative warm clouds, which can be explained by multiplication of existing ice crystals. However, the role of ice particles in redistributing sun light is minimal.
Manuel Moser, Christiane Voigt, Tina Jurkat-Witschas, Valerian Hahn, Guillaume Mioche, Olivier Jourdan, Régis Dupuy, Christophe Gourbeyre, Alfons Schwarzenboeck, Johannes Lucke, Yvonne Boose, Mario Mech, Stephan Borrmann, André Ehrlich, Andreas Herber, Christof Lüpkes, and Manfred Wendisch
Atmos. Chem. Phys., 23, 7257–7280, https://doi.org/10.5194/acp-23-7257-2023, https://doi.org/10.5194/acp-23-7257-2023, 2023
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This study provides a comprehensive microphysical and thermodynamic phase analysis of low-level clouds in the northern Fram Strait, above the sea ice and the open ocean, during spring and summer. Using airborne in situ cloud data, we show that the properties of Arctic low-level clouds vary significantly with seasonal meteorological situations and surface conditions. The observations presented in this study can help one to assess the role of clouds in the Arctic climate system.
Rachel Atlas and Christopher S. Bretherton
Atmos. Chem. Phys., 23, 4009–4030, https://doi.org/10.5194/acp-23-4009-2023, https://doi.org/10.5194/acp-23-4009-2023, 2023
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The tropical tropopause layer exists between the troposphere and the stratosphere in the tropics. Very thin cirrus clouds cool Earth's surface by scrubbing water vapor (a greenhouse gas) out of air parcels as they ascend through the tropical tropopause layer on their way to the stratosphere. We show observational evidence from aircraft that small-scale (< 100 km) gravity waves and turbulence increase the amount of ice in these clouds and may allow them to remove more water vapor from the air.
Konstantinos Matthaios Doulgeris, Ville Vakkari, Ewan J. O'Connor, Veli-Matti Kerminen, Heikki Lihavainen, and David Brus
Atmos. Chem. Phys., 23, 2483–2498, https://doi.org/10.5194/acp-23-2483-2023, https://doi.org/10.5194/acp-23-2483-2023, 2023
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We investigated how different long-range-transported air masses can affect the microphysical properties of low-level clouds in a clean subarctic environment. A connection was revealed. Higher values of cloud droplet number concentrations were related to continental air masses, whereas the lowest values of number concentrations were related to marine air masses. These were characterized by larger cloud droplets. Clouds in all regions were sensitive to increases in cloud number concentration.
Fayçal Lamraoui, Martina Krämer, Armin Afchine, Adam B. Sokol, Sergey Khaykin, Apoorva Pandey, and Zhiming Kuang
Atmos. Chem. Phys., 23, 2393–2419, https://doi.org/10.5194/acp-23-2393-2023, https://doi.org/10.5194/acp-23-2393-2023, 2023
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Cirrus in the tropical tropopause layer (TTL) can play a key role in vertical transport. We investigate the role of different cloud regimes and the associated ice habits in regulating the properties of the TTL. We use high-resolution numerical experiments at the scales of large-eddy simulations (LESs) and aircraft measurements. We found that LES-scale parameterizations that predict ice shape are crucial for an accurate representation of TTL cirrus and thus the associated (de)hydration process.
Yun Li, Christoph Mahnke, Susanne Rohs, Ulrich Bundke, Nicole Spelten, Georgios Dekoutsidis, Silke Groß, Christiane Voigt, Ulrich Schumann, Andreas Petzold, and Martina Krämer
Atmos. Chem. Phys., 23, 2251–2271, https://doi.org/10.5194/acp-23-2251-2023, https://doi.org/10.5194/acp-23-2251-2023, 2023
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The radiative effect of aviation-induced cirrus is closely related to ambient conditions and its microphysical properties. Our study investigated the occurrence of contrail and natural cirrus measured above central Europe in spring 2014. It finds that contrail cirrus appears frequently in the pressure range 200 to 245 hPa and occurs more often in slightly ice-subsaturated environments than expected. Avoiding slightly ice-subsaturated regions by aviation might help mitigate contrail cirrus.
Flor Vanessa Maciel, Minghui Diao, and Ryan Patnaude
Atmos. Chem. Phys., 23, 1103–1129, https://doi.org/10.5194/acp-23-1103-2023, https://doi.org/10.5194/acp-23-1103-2023, 2023
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Aerosol indirect effects on cirrus clouds are investigated during cirrus evolution, using global-scale in situ observations and climate model simulations. As cirrus evolves, the mechanisms to form ice crystals also change with time. Both small and large aerosols are found to affect cirrus properties. Southern Hemisphere cirrus appears to be more sensitive to additional aerosols. The climate model underestimates ice crystal mass, likely due to biases of relative humidity and vertical velocity.
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Short summary
We report on ambient concentrations of ice nuclei, measured on the Cabo Verde islands. Concentrations are found to exponentially increase by 7 orders of magnitude from −5 to −38 °C. At each temperature, the frequency distribution of observed concentrations can be described by a lognormal distribution, typical for random dilution of substances during transport. Random dilution is found to account for larger fluctuations in IN concentration than seasonal changes and changes in air mass origin.
We report on ambient concentrations of ice nuclei, measured on the Cabo Verde islands....
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