Articles | Volume 21, issue 1
https://doi.org/10.5194/acp-21-561-2021
© Author(s) 2021. 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-21-561-2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| Highlight paper
| 
15 Jan 2021
Research article | Highlight paper |
| 15 Jan 2021
| 15 Jan 2021
On the ice-nucleating potential of warm hydrometeors in mixed-phase clouds
Institute for Hydromechanics, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
Agathe Chouippe
Institute for Hydromechanics, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
now at: ICube, Fluid Mechanics Group, Université de Strasbourg, Strasbourg, France
Markus Uhlmann
Institute for Hydromechanics, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
Jan Dušek
ICube, Fluid Mechanics Group, Université de Strasbourg, Strasbourg, France
Thomas Leisner
Institute of Meteorology and Climate Research, Atmospheric Aerosol Research Department, Karlsruhe Institute of Technology (KIT),
Eggenstein-Leopoldshafen, Germany
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Alexander Julian Böhmländer, Larissa Lacher, Kristina Höhler, David Brus, Konstantinos-Matthaios Doulgeris, Jessica Girdwood, Thomas Leisner, and Ottmar Möhler
Earth Syst. Sci. Data Discuss., https://doi.org/10.5194/essd-2025-87, https://doi.org/10.5194/essd-2025-87, 2025
Preprint under review for ESSD
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Clouds play a key role in weather and climate. Pure liquid water droplets are liquid until about -35 °C without the presence of a small subset of aerosols, ice-nucleating particles (INPs). These INPs lead to primary ice formation and therefore impact the phase of clouds. The dataset described herein provides INP concentration measurements at two altitudes. Connecting this data to synoptic conditions and ambient data might provide a better understanding of INPs in Finnish Lapland.
Feng Jiang, Harald Saathoff, Uzoamaka Ezenobi, Junwei Song, Hengheng Zhang, Linyu Gao, and Thomas Leisner
Atmos. Chem. Phys., 25, 1917–1930, https://doi.org/10.5194/acp-25-1917-2025, https://doi.org/10.5194/acp-25-1917-2025, 2025
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The chemical composition of brown carbon in the particle and gas phase was determined by mass spectrometry. BrC in the gas phase was mainly controlled by secondary formation and particle-to-gas partitioning. BrC in the particle phase was mainly from secondary formation. This work helps to get a better understanding of diurnal variations and the sources of brown carbon aerosol at a rural location in central Europe.
Junwei Song, Georgios I. Gkatzelis, Ralf Tillmann, Nicolas Brüggemann, Thomas Leisner, and Harald Saathoff
Atmos. Chem. Phys., 24, 13199–13217, https://doi.org/10.5194/acp-24-13199-2024, https://doi.org/10.5194/acp-24-13199-2024, 2024
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Biogenic volatile organic compounds (BVOCs) and organic aerosol (OA) particles were measured online in a stressed spruce-dominated forest. OA was mainly attributed to the monoterpene oxidation products. The mixing ratios of BVOCs were higher than the values previously measured in other temperate forests. The results demonstrate that BVOCs are influenced not only by meteorology and biogenic emissions but also by local anthropogenic emissions and subsequent chemical transformation processes.
Hengheng Zhang, Wei Huang, Xiaoli Shen, Ramakrishna Ramisetty, Junwei Song, Olga Kiseleva, Christopher Claus Holst, Basit Khan, Thomas Leisner, and Harald Saathoff
Atmos. Chem. Phys., 24, 10617–10637, https://doi.org/10.5194/acp-24-10617-2024, https://doi.org/10.5194/acp-24-10617-2024, 2024
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Our study unravels how stagnant winter conditions elevate aerosol levels in Stuttgart. Cloud cover at night plays a pivotal role, impacting morning air quality. Validating a key model, our findings aid accurate air quality predictions, crucial for effective pollution mitigation in urban areas.
Alexander Julian Böhmländer, Larissa Lacher, David Brus, Konstantinos-Matthaios Doulgeris, Zoé Brasseur, Matthew Boyer, Joel Kuula, Thomas Leisner, and Ottmar Möhler
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2024-120, https://doi.org/10.5194/amt-2024-120, 2024
Revised manuscript accepted for AMT
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Clouds and aerosol are important for weather and climate. Typically, pure water cloud droplets stay liquid until around -35 °C, unless they come into contact with ice-nucleating particles (INPs). INPs are a rare subset of aerosol particles. Using uncrewed aerial vehicles (UAVs), it is possible to collect aerosol particles and analyse them on their ice-nucleating ability. This study describes the test and validation of a sampling setup that can be used to collect aerosol particles onto a filter.
Junwei Song, Harald Saathoff, Feng Jiang, Linyu Gao, Hengheng Zhang, and Thomas Leisner
Atmos. Chem. Phys., 24, 6699–6717, https://doi.org/10.5194/acp-24-6699-2024, https://doi.org/10.5194/acp-24-6699-2024, 2024
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This study presents concurrent online measurements of organic gas and particles (VOCs and OA) at a forested site in summer. Both VOCs and OA were largely contributed by oxygenated organic compounds. Semi-volatile oxygenated OA and organic nitrate formed from monoterpenes and sesquiterpenes contributed significantly to nighttime particle growth. The results help us to understand the causes of nighttime particle growth regularly observed in summer in central European rural forested environments.
Hengheng Zhang, Christian Rolf, Ralf Tillmann, Christian Wesolek, Frank Gunther Wienhold, Thomas Leisner, and Harald Saathoff
Aerosol Research, 2, 135–151, https://doi.org/10.5194/ar-2-135-2024, https://doi.org/10.5194/ar-2-135-2024, 2024
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Our study employs advanced tools, including scanning lidar, balloons, and UAVs, to explore aerosol particles in the atmosphere. The scanning lidar offers distinctive near-ground-level insights, enriching our comprehension of aerosol distribution from ground level to the free troposphere. This research provides valuable data for comparing remote sensing and in situ aerosol measurements, advancing our understanding of aerosol impacts on radiative transfer, clouds, and air quality.
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.
Feng Jiang, Kyla Siemens, Claudia Linke, Yanxia Li, Yiwei Gong, Thomas Leisner, Alexander Laskin, and Harald Saathoff
Atmos. Chem. Phys., 24, 2639–2649, https://doi.org/10.5194/acp-24-2639-2024, https://doi.org/10.5194/acp-24-2639-2024, 2024
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We investigated the optical properties, chemical composition, and formation mechanisms of secondary organic aerosol (SOA) and brown carbon (BrC) from the oxidation of indole with and without NO2 in the Aerosol Interaction and Dynamics in the Atmosphere (AIDA) simulation chamber. This work is one of the very few to link the optical properties and chemical composition of indole SOA with and without NO2 by simulation chamber experiments.
Yiwei Gong, Feng Jiang, Yanxia Li, Thomas Leisner, and Harald Saathoff
Atmos. Chem. Phys., 24, 167–184, https://doi.org/10.5194/acp-24-167-2024, https://doi.org/10.5194/acp-24-167-2024, 2024
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This study investigates the role of the important atmospheric reactive intermediates in the formation of dimers and aerosol in monoterpene ozonolysis at different temperatures. Through conducting a series of chamber experiments and utilizing chemical kinetic and aerosol dynamic models, the SOA formation processes are better described, especially for colder regions. The results can be used to improve the chemical mechanism modeling of monoterpenes and SOA parameterization in transport models.
Mohit Singh, Stephanie Helen Jones, Alexei Kiselev, Denis Duft, and Thomas Leisner
Atmos. Meas. Tech., 16, 5205–5215, https://doi.org/10.5194/amt-16-5205-2023, https://doi.org/10.5194/amt-16-5205-2023, 2023
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We introduce a novel method for simultaneous measurement of the viscosity and surface tension of metastable liquids. Our approach is based on the phase analysis of excited shape oscillations in levitated droplets. It is applicable to a wide range of atmospheric conditions and can monitor changes in real time. The technique holds great promise for investigating the effect of atmospheric processing on the viscosity and surface tension of solution droplets in equilibrium with water vapour.
Feng Jiang, Junwei Song, Jonas Bauer, Linyu Gao, Magdalena Vallon, Reiner Gebhardt, Thomas Leisner, Stefan Norra, and Harald Saathoff
Atmos. Chem. Phys., 22, 14971–14986, https://doi.org/10.5194/acp-22-14971-2022, https://doi.org/10.5194/acp-22-14971-2022, 2022
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We studied brown carbon aerosol during typical summer and winter periods in downtown Karlsruhe in southwestern Germany. The chromophore and chemical composition of brown carbon was determined by excitation–emission spectroscopy and mass spectrometry. The chromophore types and sources were substantially different in winter and summer. Humic-like chromophores of different degrees of oxidation dominated and were associated with molecules of different molecular weight and nitrogen content.
Fritz Waitz, Martin Schnaiter, Thomas Leisner, and Emma Järvinen
Atmos. Chem. Phys., 22, 7087–7103, https://doi.org/10.5194/acp-22-7087-2022, https://doi.org/10.5194/acp-22-7087-2022, 2022
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Riming, i.e., the accretion of small droplets on the surface of ice particles via collision, is one of the major uncertainties in model prediction of mixed-phase clouds. We discuss the occurrence (up to 50% of particles) and aging of rimed ice particles and show correlations of the occurrence and the degree of riming with ambient meteorological parameters using data gathered by the Particle Habit Imaging and Polar Scattering (PHIPS) probe during three airborne in situ field campaigns.
Linyu Gao, Junwei Song, Claudia Mohr, Wei Huang, Magdalena Vallon, Feng Jiang, Thomas Leisner, and Harald Saathoff
Atmos. Chem. Phys., 22, 6001–6020, https://doi.org/10.5194/acp-22-6001-2022, https://doi.org/10.5194/acp-22-6001-2022, 2022
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We study secondary organic aerosol (SOA) from β-caryophyllene (BCP) ozonolysis with and without nitrogen oxides over 213–313 K in the simulation chamber. The yields and the rate constants were determined at 243–313 K. Chemical compositions varied at different temperatures, indicating a strong impact on the BCP ozonolysis pathways. This work helps to better understand the SOA from BCP ozonolysis for conditions representative of the real atmosphere from the boundary layer to the upper troposphere.
Magdalena Vallon, Linyu Gao, Feng Jiang, Bianca Krumm, Jens Nadolny, Junwei Song, Thomas Leisner, and Harald Saathoff
Atmos. Meas. Tech., 15, 1795–1810, https://doi.org/10.5194/amt-15-1795-2022, https://doi.org/10.5194/amt-15-1795-2022, 2022
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A LED-based light source has been constructed for the AIDA simulation chamber at the Karlsruhe Institute of Technology. It allows aerosol formation and ageing studies under atmospherically relevant illumination intensities and spectral characteristics at temperatures from –90 °C to 30 °C with the possibility of changing the photon flux and irradiation spectrum at any point. The first results of photolysis experiments with 2,3-pentanedione, iron oxalate and a brown carbon component are shown.
Ulrich Platt, Thomas Wagner, Jonas Kuhn, and Thomas Leisner
Atmos. Meas. Tech., 14, 6867–6883, https://doi.org/10.5194/amt-14-6867-2021, https://doi.org/10.5194/amt-14-6867-2021, 2021
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Absorption spectroscopy of scattered sunlight is extremely useful for the analysis of atmospheric trace gas distributions. A central parameter for the achievable sensitivity of spectroscopic instruments is the light throughput, which can be enhanced in a number of ways. We present new ideas and considerations of how instruments could be optimized. Particular emphasis is on arrays of massively parallel instruments. Such arrays can reduce the size and weight of instruments by orders of magnitude.
Julia Schneider, Kristina Höhler, Robert Wagner, Harald Saathoff, Martin Schnaiter, Tobias Schorr, Isabelle Steinke, Stefan Benz, Manuel Baumgartner, Christian Rolf, Martina Krämer, Thomas Leisner, and Ottmar Möhler
Atmos. Chem. Phys., 21, 14403–14425, https://doi.org/10.5194/acp-21-14403-2021, https://doi.org/10.5194/acp-21-14403-2021, 2021
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Homogeneous freezing is a relevant mechanism for the formation of cirrus clouds in the upper troposphere. Based on an extensive set of homogeneous freezing experiments at the AIDA chamber with aqueous sulfuric acid aerosol, we provide a new fit line for homogeneous freezing onset conditions of sulfuric acid aerosol focusing on cirrus temperatures. In the atmosphere, homogeneous freezing thresholds have important implications on the cirrus cloud occurrence and related cloud radiative effects.
Alexei A. Kiselev, Alice Keinert, Tilia Gaedeke, Thomas Leisner, Christoph Sutter, Elena Petrishcheva, and Rainer Abart
Atmos. Chem. Phys., 21, 11801–11814, https://doi.org/10.5194/acp-21-11801-2021, https://doi.org/10.5194/acp-21-11801-2021, 2021
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Alkali feldspar is the most abundant mineral in the Earth's crust and is often present in mineral dust aerosols that are responsible for the formation of rain and snow in clouds. However, the cloud droplets containing pure potassium-rich feldspar would not freeze unless cooled down to a very low temperature. Here we show that partly replacing potassium with sodium would induce fracturing of feldspar, exposing a crystalline surface that could initiate freezing at higher temperature.
Hengheng Zhang, Frank Wagner, Harald Saathoff, Heike Vogel, Gholam Ali Hoshyaripour, Vanessa Bachmann, Jochen Förstner, and Thomas Leisner
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2021-193, https://doi.org/10.5194/amt-2021-193, 2021
Revised manuscript not accepted
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The evolution and the properties of Saharan dust plume were characterized by LIDARs, a sun photometer, and a regional transport model. Comparison between LIDAR measurements, sun photometer and ICON-ART predictions shows a good agreement for dust arrival time, dust layer height, and dust structure but also that the model overestimates the backscatter coefficients by a factor of (2.2 ± 0.16) and underestimate aerosol optical depth by a factor of (1.5 ± 0.11).
Barbara Bertozzi, Robert Wagner, Junwei Song, Kristina Höhler, Joschka Pfeifer, Harald Saathoff, Thomas Leisner, and Ottmar Möhler
Atmos. Chem. Phys., 21, 10779–10798, https://doi.org/10.5194/acp-21-10779-2021, https://doi.org/10.5194/acp-21-10779-2021, 2021
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Internally mixed particles composed of sulfate and organics are among the most abundant aerosol types. Their ice nucleation (IN) ability influences the formation of cirrus and, thus, the climate. We show that the presence of a thin organic coating suppresses the heterogeneous IN ability of crystalline ammonium sulfate particles. However, the IN ability of the same particle can substantially change if subjected to atmospheric processing, mainly due to differences in the resulting morphology.
Fritz Waitz, Martin Schnaiter, Thomas Leisner, and Emma Järvinen
Atmos. Meas. Tech., 14, 3049–3070, https://doi.org/10.5194/amt-14-3049-2021, https://doi.org/10.5194/amt-14-3049-2021, 2021
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A major challenge in the observations of mixed-phase clouds remains the phase discrimination and sizing of cloud droplets and ice crystals, especially for particles with diameters smaller than 0.1 mm. Here, we present a new method to derive the phase and size of single cloud particles using their angular-light-scattering information. Comparisons with other in situ instruments in three case studies show good agreement.
Julia Schneider, Kristina Höhler, Paavo Heikkilä, Jorma Keskinen, Barbara Bertozzi, Pia Bogert, Tobias Schorr, Nsikanabasi Silas Umo, Franziska Vogel, Zoé Brasseur, Yusheng Wu, Simo Hakala, Jonathan Duplissy, Dmitri Moisseev, Markku Kulmala, Michael P. Adams, Benjamin J. Murray, Kimmo Korhonen, Liqing Hao, Erik S. Thomson, Dimitri Castarède, Thomas Leisner, Tuukka Petäjä, and Ottmar Möhler
Atmos. Chem. Phys., 21, 3899–3918, https://doi.org/10.5194/acp-21-3899-2021, https://doi.org/10.5194/acp-21-3899-2021, 2021
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By triggering the formation of ice crystals, ice-nucleating particles (INP) strongly influence cloud formation. Continuous, long-term measurements are needed to characterize the atmospheric INP variability. Here, a first long-term time series of INP spectra measured in the boreal forest for more than 1 year is presented, showing a clear seasonal cycle. It is shown that the seasonal dependency of INP concentrations and prevalent INP types is driven by the abundance of biogenic aerosol.
Robert Wagner, Baptiste Testa, Michael Höpfner, Alexei Kiselev, Ottmar Möhler, Harald Saathoff, Jörn Ungermann, and Thomas Leisner
Atmos. Meas. Tech., 14, 1977–1991, https://doi.org/10.5194/amt-14-1977-2021, https://doi.org/10.5194/amt-14-1977-2021, 2021
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During the Asian summer monsoon period, air pollutants are transported from layers near the ground to high altitudes of 13 to 18 km in the atmosphere. Infrared measurements have shown that particles composed of solid ammonium nitrate are a major part of these pollutants. To enable the quantitative analysis of the infrared spectra, we have determined for the first time accurate optical constants of ammonium nitrate for the low-temperature conditions of the upper atmosphere.
Alexei Korolev and Thomas Leisner
Atmos. Chem. Phys., 20, 11767–11797, https://doi.org/10.5194/acp-20-11767-2020, https://doi.org/10.5194/acp-20-11767-2020, 2020
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Secondary ice production (SIP) plays a key role in the formation of ice particles in tropospheric clouds. This work presents a critical review of the laboratory studies related to secondary ice production. It aims to identify gaps in our knowledge of SIP as well as to stimulate further laboratory studies focused on obtaining a quantitative description of efficiencies for each SIP mechanism.
Isabelle Steinke, Naruki Hiranuma, Roger Funk, Kristina Höhler, Nadine Tüllmann, Nsikanabasi Silas Umo, Peter G. Weidler, Ottmar Möhler, and Thomas Leisner
Atmos. Chem. Phys., 20, 11387–11397, https://doi.org/10.5194/acp-20-11387-2020, https://doi.org/10.5194/acp-20-11387-2020, 2020
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In this study, we highlight the potential impact of particles from certain terrestrial sources on the formation of ice crystals in clouds. In particular, we focus on biogenic particles consisting of various organic compounds, which makes it very difficult to predict the ice nucleation properties of complex ambient particles. We find that these ambient particles are often more ice active than individual components.
Xiaoli Shen, Heike Vogel, Bernhard Vogel, Wei Huang, Claudia Mohr, Ramakrishna Ramisetty, Thomas Leisner, André S. H. Prévôt, and Harald Saathoff
Atmos. Chem. Phys., 19, 13189–13208, https://doi.org/10.5194/acp-19-13189-2019, https://doi.org/10.5194/acp-19-13189-2019, 2019
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This study provides good insight into the chemical nature and complex origin of aerosols by combining comprehensive field observations and transport modelling. We suggest that factors related to topography, metrological conditions, local emissions, in situ formation and growth, regional transport, and the interaction of biogenic and anthropogenic compounds need to be considered for a comprehensive understanding of aerosol processes.
Tasha Aylett, James S. A. Brooke, Alexander D. James, Mario Nachbar, Denis Duft, Thomas Leisner, and John M. C. Plane
Atmos. Chem. Phys., 19, 12767–12777, https://doi.org/10.5194/acp-19-12767-2019, https://doi.org/10.5194/acp-19-12767-2019, 2019
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Interplanetary dust particles entering the Earth's atmosphere often melt and evaporate, injecting metals such as iron and magnesium into the atmosphere between 80 and 105 km. These metals become oxidized and then coagulate into small particles a few nanometres is size, known as meteoric smoke. In this study, iron oxide smoke particles were created in the laboratory, and their composition and optical properties were determined in order to understand satellite measurements.
Wei Huang, Harald Saathoff, Xiaoli Shen, Ramakrishna Ramisetty, Thomas Leisner, and Claudia Mohr
Atmos. Chem. Phys., 19, 11687–11700, https://doi.org/10.5194/acp-19-11687-2019, https://doi.org/10.5194/acp-19-11687-2019, 2019
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We investigate the molecular composition and volatility of oxygenated organic aerosol (OOA) particles in summer and winter in Stuttgart, Germany. OOA in summer is more influenced by biogenic emissions, while in winter biomass burning emissions are an important source. OOA in winter is also less volatile. Potential reasons are discussed in our paper. Our study shows the important contributions of nonfossil OA from biogenic and biomass burning even in an urban area with high traffic emissions.
Martin Schnaiter, Claudia Linke, Inas Ibrahim, Alexei Kiselev, Fritz Waitz, Thomas Leisner, Stefan Norra, and Till Rehm
Atmos. Chem. Phys., 19, 10829–10844, https://doi.org/10.5194/acp-19-10829-2019, https://doi.org/10.5194/acp-19-10829-2019, 2019
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When combustion particles are deposited to the ground, they darken Earth's snow and ice surfaces by even tiny quantities. This darkening reduces the back reflection of sunlight and induces an additional climate warming. Particles from fresh snow samples were investigated according to their light absorption strength. Enhanced absorption was found in the snow that cannot fully be attributed to combustion particles. Dust and biogenic matter are likely the cause of this additional snow darkening.
Nsikanabasi Silas Umo, Robert Wagner, Romy Ullrich, Alexei Kiselev, Harald Saathoff, Peter G. Weidler, Daniel J. Cziczo, Thomas Leisner, and Ottmar Möhler
Atmos. Chem. Phys., 19, 8783–8800, https://doi.org/10.5194/acp-19-8783-2019, https://doi.org/10.5194/acp-19-8783-2019, 2019
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Annually, over 600 Tg of coal fly ash (CFA) is produced; a significant proportion of this amount is injected into the atmosphere, which could significantly contribute to heterogeneous ice formation in clouds. This study presents an improved understanding of CFA particles' behaviour in forming ice in clouds, especially when exposed to lower temperatures before being re-circulated in the upper troposphere or entrained into the lower troposphere.
Xiaoli Shen, Harald Saathoff, Wei Huang, Claudia Mohr, Ramakrishna Ramisetty, and Thomas Leisner
Atmos. Meas. Tech., 12, 2219–2240, https://doi.org/10.5194/amt-12-2219-2019, https://doi.org/10.5194/amt-12-2219-2019, 2019
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Based on single-particle mass spectra from field measurements in the upper Rhine valley, we identified characteristic particle classes and estimated their mass contributions without the need of a reference instrument in the field. Our study provides a good example for quantitative interpretation of single-particle data. Together with the complimentary results from bulk measurements, we have shown how a better understanding of the mixing state of ambient aerosol particles can be achieved.
Mario Nachbar, Henrike Wilms, Denis Duft, Tasha Aylett, Kensei Kitajima, Takuya Majima, John M. C. Plane, Markus Rapp, and Thomas Leisner
Atmos. Chem. Phys., 19, 4311–4322, https://doi.org/10.5194/acp-19-4311-2019, https://doi.org/10.5194/acp-19-4311-2019, 2019
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Polar mesospheric clouds (PMC) are water ice clouds forming on nanoparticles in the polar summer mesopause. We investigate the impact of solar radiation on PMC formation in the laboratory. We show that Mie theory calculations combined with an equilibrium temperature model presented in this work predict the warming of the particles very well. Using this model we demonstrate that the impact of solar radiation on ice particle formation is significantly lower than previously assumed.
Denis Duft, Mario Nachbar, and Thomas Leisner
Atmos. Chem. Phys., 19, 2871–2879, https://doi.org/10.5194/acp-19-2871-2019, https://doi.org/10.5194/acp-19-2871-2019, 2019
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How ice particles form in polar mesospheric clouds is still a challenging question. We measured the water adsorption and onset conditions for ice growth on meteoric smoke analogue particles in the laboratory. We find that the particles activate by growth of amorphous ice and at much warmer conditions than previously assumed, affirming meteoric smoke as likely seeds in mesospheric ice clouds. We propose an ice-activation model and show that the particle charge does not play a significant role.
Emma Järvinen, Olivier Jourdan, David Neubauer, Bin Yao, Chao Liu, Meinrat O. Andreae, Ulrike Lohmann, Manfred Wendisch, Greg M. McFarquhar, Thomas Leisner, and Martin Schnaiter
Atmos. Chem. Phys., 18, 15767–15781, https://doi.org/10.5194/acp-18-15767-2018, https://doi.org/10.5194/acp-18-15767-2018, 2018
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Using light diffraction it is possible to detect microscopic features within ice particles that have not yet been fully characterized. Here, this technique was applied in airborne measurements, where it was found that majority of atmospheric ice particles have features that significantly change the way ice particles interact with solar light. The microscopic features make ice-containing clouds more reflective than previously thought, which could have consequences for predicting our climate.
Ramakrishna Ramisetty, Ahmed Abdelmonem, Xiaoli Shen, Harald Saathoff, Thomas Leisner, and Claudia Mohr
Atmos. Meas. Tech., 11, 4345–4360, https://doi.org/10.5194/amt-11-4345-2018, https://doi.org/10.5194/amt-11-4345-2018, 2018
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In this study we coupled a laser ablation aerosol time-of-flight (LAAPTOF) single-particle mass spectrometer, originally equipped with an excimer laser, to a femtosecond laser. The objective was to assess the influence of the higher laser power density of the femtosecond laser on ablation–ionization of atmospheric particles, ion signal, and ultimately quantitative abilities of the single-particle mass spectrometer.
Xiaoli Shen, Ramakrishna Ramisetty, Claudia Mohr, Wei Huang, Thomas Leisner, and Harald Saathoff
Atmos. Meas. Tech., 11, 2325–2343, https://doi.org/10.5194/amt-11-2325-2018, https://doi.org/10.5194/amt-11-2325-2018, 2018
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This paper presents performance data and reference spectra from the commercially available single-particle mass spectrometer LAAPTOF. The main characteristics of the instrument, like its detection efficiency, are given for a wide particle size range. Furthermore, reference mass spectra for 32 well-defined different particle types relevant for atmospheric aerosol compounds are presented. It is shown that these reference mass spectra are very useful in analysis of atmospheric aerosol particles.
Mario Nachbar, Denis Duft, and Thomas Leisner
Atmos. Chem. Phys., 18, 3419–3431, https://doi.org/10.5194/acp-18-3419-2018, https://doi.org/10.5194/acp-18-3419-2018, 2018
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The crystallization process of amorphous ice below 160 K forms nano-crystalline ice. We report high-quality vapor pressure measurements over ice crystallized from amorphous ice below 160 K. We show that the vapor pressure is increased by more than 100 % compared to bulk crystalline ice and that amorphous ice always forms first, followed by the crystallization of nano-crystalline ice. Our findings are relevant for cold ice clouds in the atmospheres of planets, e.g., Earth and Mars.
Wei Huang, Harald Saathoff, Aki Pajunoja, Xiaoli Shen, Karl-Heinz Naumann, Robert Wagner, Annele Virtanen, Thomas Leisner, and Claudia Mohr
Atmos. Chem. Phys., 18, 2883–2898, https://doi.org/10.5194/acp-18-2883-2018, https://doi.org/10.5194/acp-18-2883-2018, 2018
Sylvia C. Sullivan, Corinna Hoose, Alexei Kiselev, Thomas Leisner, and Athanasios Nenes
Atmos. Chem. Phys., 18, 1593–1610, https://doi.org/10.5194/acp-18-1593-2018, https://doi.org/10.5194/acp-18-1593-2018, 2018
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Ice multiplication (IM) processes can have a profound impact on cloud and precipitation development but are poorly understood. Here we study whether a lower limit of ice nuclei exists to initiate IM. The lower limit is found to be extremely low (0.01 per liter or less). A counterintuitive but profound conclusion thus emerges: IM requires cloud formation around a thermodynamic
sweet spotand is sensitive to fluctuations in cloud condensation nuclei concentration alone.
Martin Schnaiter, Emma Järvinen, Ahmed Abdelmonem, and Thomas Leisner
Atmos. Meas. Tech., 11, 341–357, https://doi.org/10.5194/amt-11-341-2018, https://doi.org/10.5194/amt-11-341-2018, 2018
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PHIPS-HALO is a novel aircraft instrument for cloud research. It combines microscopic imaging of single cloud particles with the measurement of their spacial light scattering properties. The knowledge of how atmospheric ice particles in clouds scatter visible light is important for improving future climate models.
Claudia Linke, Inas Ibrahim, Nina Schleicher, Regina Hitzenberger, Meinrat O. Andreae, Thomas Leisner, and Martin Schnaiter
Atmos. Meas. Tech., 9, 5331–5346, https://doi.org/10.5194/amt-9-5331-2016, https://doi.org/10.5194/amt-9-5331-2016, 2016
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Various carbonaceous materials are present in the atmosphere. Besides gaseous organic compounds, carbonaceous particles like soot are emitted into the air from traffic sources, residential wood combustion, or wildfires. Variable chemical compositions of such materials, which often result from incomplete combustion processes, show differences in the absorption behavior at visible wavelengths. Our instrument is able to measure the absorption at three visible wavelengths.
Andreas Peckhaus, Alexei Kiselev, Thibault Hiron, Martin Ebert, and Thomas Leisner
Atmos. Chem. Phys., 16, 11477–11496, https://doi.org/10.5194/acp-16-11477-2016, https://doi.org/10.5194/acp-16-11477-2016, 2016
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The precipitation in midlatitude clouds proceeds predominantly via nucleation of ice in the supercooled droplets containing foreign inclusions, like feldspar mineral dust, that have been recently identified as one of the most active ice nucleating agents in the atmosphere. We have built an apparatus to observe the freezing of feldspar immersed in up to 1500 identical droplets simultaneously. With this setup we investigated four feldspar samples and show that it can induce freezing at −5 °C.
Ahmed Abdelmonem, Emma Järvinen, Denis Duft, Edwin Hirst, Steffen Vogt, Thomas Leisner, and Martin Schnaiter
Atmos. Meas. Tech., 9, 3131–3144, https://doi.org/10.5194/amt-9-3131-2016, https://doi.org/10.5194/amt-9-3131-2016, 2016
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The properties of ice crystals present in mixed-phase and ice clouds influence the radiation properties, precipitation occurrence and lifetime of these clouds. It is necessary to investigate the optical and microphysical properties of cloud particles particularly in situ, and to get correlation between these properties. To this end we have developed PHIPS-HALO to measure the optical properties and the corresponding microphysical parameters of individual cloud particles simultaneously.
Emma Järvinen, Karoliina Ignatius, Leonid Nichman, Thomas B. Kristensen, Claudia Fuchs, Christopher R. Hoyle, Niko Höppel, Joel C. Corbin, Jill Craven, Jonathan Duplissy, Sebastian Ehrhart, Imad El Haddad, Carla Frege, Hamish Gordon, Tuija Jokinen, Peter Kallinger, Jasper Kirkby, Alexei Kiselev, Karl-Heinz Naumann, Tuukka Petäjä, Tamara Pinterich, Andre S. H. Prevot, Harald Saathoff, Thea Schiebel, Kamalika Sengupta, Mario Simon, Jay G. Slowik, Jasmin Tröstl, Annele Virtanen, Paul Vochezer, Steffen Vogt, Andrea C. Wagner, Robert Wagner, Christina Williamson, Paul M. Winkler, Chao Yan, Urs Baltensperger, Neil M. Donahue, Rick C. Flagan, Martin Gallagher, Armin Hansel, Markku Kulmala, Frank Stratmann, Douglas R. Worsnop, Ottmar Möhler, Thomas Leisner, and Martin Schnaiter
Atmos. Chem. Phys., 16, 4423–4438, https://doi.org/10.5194/acp-16-4423-2016, https://doi.org/10.5194/acp-16-4423-2016, 2016
P. Vochezer, E. Järvinen, R. Wagner, P. Kupiszewski, T. Leisner, and M. Schnaiter
Atmos. Meas. Tech., 9, 159–177, https://doi.org/10.5194/amt-9-159-2016, https://doi.org/10.5194/amt-9-159-2016, 2016
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To study clouds constituting of liquid droplets as well as ice particles we used the latest versions of the Small Ice Detector which record high resolution scattering patterns of individual small cloud particles. In the case of a droplet its precise size is obtained and for ice particles its shape is deduced from the scattering pattern.We present results from artificial clouds at the AIDA cloud chamber and natural clouds probed at a mountain top station as well as from an aircraft in the arctic.
A. Abdelmonem, J. Lützenkirchen, and T. Leisner
Atmos. Meas. Tech., 8, 3519–3526, https://doi.org/10.5194/amt-8-3519-2015, https://doi.org/10.5194/amt-8-3519-2015, 2015
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This manuscript belongs and is important to the environmental and atmospheric science, particularly cloud formation and cloud seeding, and presents a setup to apply Second Harmonic Generation spectroscopy to heterogeneous freezing research. We describe the setup and provide first results on temperature-dependent structural changes of water on the surfaces of two relevant atmospheric aerosol substances (sapphire and mica as poor and good ice nucleators, respectively).
I. Steinke, C. Hoose, O. Möhler, P. Connolly, and T. Leisner
Atmos. Chem. Phys., 15, 3703–3717, https://doi.org/10.5194/acp-15-3703-2015, https://doi.org/10.5194/acp-15-3703-2015, 2015
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Ice nucleation in clouds has a significant influence on the global radiative budget and the hydrological cycle. Several studies have investigated the ice formation in droplets and parameterizations have been developed in order to include immersion freezing in climate models. In contrast, there are fewer studies regarding the conversion of water vapor into ice (so-called deposition nucleation) which is the topic of this paper which investigates deposition nucleation by Arizona Test dust in detail
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.
N. Hoffmann, A. Kiselev, D. Rzesanke, D. Duft, and T. Leisner
Atmos. Meas. Tech., 6, 2373–2382, https://doi.org/10.5194/amt-6-2373-2013, https://doi.org/10.5194/amt-6-2373-2013, 2013
H. Saathoff, S. Henin, K. Stelmaszczyk, M. Petrarca, R. Delagrange, Z. Hao, J. Lüder, O. Möhler, Y. Petit, P. Rohwetter, M. Schnaiter, J. Kasparian, T. Leisner, J.-P. Wolf, and L. Wöste
Atmos. Chem. Phys., 13, 4593–4604, https://doi.org/10.5194/acp-13-4593-2013, https://doi.org/10.5194/acp-13-4593-2013, 2013
J. Skrotzki, P. Connolly, M. Schnaiter, H. Saathoff, O. Möhler, R. Wagner, M. Niemand, V. Ebert, and T. Leisner
Atmos. Chem. Phys., 13, 4451–4466, https://doi.org/10.5194/acp-13-4451-2013, https://doi.org/10.5194/acp-13-4451-2013, 2013
Related subject area
Subject: Clouds and Precipitation | Research Activity: Atmospheric Modelling and Data Analysis | Altitude Range: Troposphere | Science Focus: Physics (physical properties and processes)
Constraining aerosol–cloud adjustments by uniting surface observations with a perturbed parameter ensemble
Investigating ice formation pathways using a novel two-moment multi-class cloud microphysics scheme
Microphysics regimes due to haze–cloud interactions: cloud oscillation and cloud collapse
Impact of secondary ice production on thunderstorm electrification under different aerosol conditions
Accelerated impact of airborne glaciogenic seeding of stratiform clouds by turbulence
Model analysis of biases in the satellite-diagnosed aerosol effect on the cloud liquid water path
Evaluation of biases in mid-to-high-latitude surface snowfall and cloud phase in ERA5 and CMIP6 using satellite observations
Failed cyclogenesis of a mesoscale convective system near Cape Verde: The role of the Saharan trade wind layer among other inhibiting factors observed during the CADDIWA field campaign
Dynamical imprints on precipitation cluster statistics across a hierarchy of high-resolution simulations
Technical note: Phase space depiction of CCN activation and cloud droplet diffusional growth
Role of a key microphysical factor in mixed-phase stratocumulus clouds and their interactions with aerosols
Investigating the impact of subgrid-scale aerosol-cloud interaction on mesoscale meteorology prediction
Correction of ERA5 temperature and relative humidity biases by bivariate quantile mapping for contrail formation analysis
Can pollen affect precipitation?
Potential impacts of marine fuel regulations on an Arctic stratocumulus case and its radiative response
The impact of the mesh size and microphysics scheme on the representation of mid-level clouds in the ICON model in hilly and complex terrain
The role of ascent timescales for warm conveyor belt (WCB) moisture transport into the upper troposphere and lower stratosphere (UTLS)
Magnitude and timescale of liquid water path adjustments to cloud droplet number concentration perturbations for nocturnal non-precipitating marine stratocumulus
On the Processes Determining the Slope of Cloud-Water Adjustments in Non-Precipitating Stratocumulus
Estimating the concentration of silver iodide needed to detect unambiguous signatures of glaciogenic cloud seeding
On the impact of thunder on cloud ice crystals and droplets
Ice-nucleating particle concentration impacts cloud properties over Dronning Maud Land, East Antarctica, in COSMO-CLM2
Numerical simulation of aerosol concentration effects on cloud droplet size spectrum evolutions of warm stratiform clouds in Jiangxi, China
The impact of aerosol on cloud water: a heuristic perspective
Cold pools mediate mesoscale adjustments of trade-cumulus fields to changes in cloud-droplet number concentration
The presence of clouds lowers climate sensitivity in the MPI-ESM1.2 climate model
Diurnal variation in an amplified canopy urban heat island during heat wave periods in the megacity of Beijing: roles of mountain–valley breeze and urban morphology
Diurnal evolution of non-precipitating marine stratocumuli in a large-eddy simulation ensemble
Ambient and Intrinsic Dependencies of Evolving Ice-Phase Particles within a Decaying Winter Storm During IMPACTS
Counteracting Influences of Gravitational Settling Modulate Aerosol Impacts on Cloud Base Lowering Fog Characteristics
Numerical Case Study of the Aerosol-Cloud-Interactions in Warm Boundary Layer Clouds over the Eastern North Atlantic with an Interactive Chemistry Module
High ice water content in tropical mesoscale convective systems (a conceptual model)
Evolution of cloud droplet temperature and lifetime in spatiotemporally varying subsaturated environments with implications for ice nucleation at cloud edges
Effect of secondary ice production processes on the simulation of ice pellets using the Predicted Particle Properties microphysics scheme
Simulated particle evolution within a winter storm: contributions of riming to radar moments and precipitation fallout
Arctic Multilayer Clouds Require Accurate Thermodynamic Profiles and Efficient Primary and Secondary Ice Processes for a Realistic Structure and Composition
A thermal-driven graupel generation process to explain dry-season convective vigor over the Amazon
Modeling homogeneous ice nucleation from drop-freezing experiments: impact of droplet volume dispersion and cooling rates
Cloud water adjustments to aerosol perturbations are buffered by solar heating in non-precipitating marine stratocumuli
Glaciation of mixed-phase clouds: insights from bulk model and bin-microphysics large-eddy simulation informed by laboratory experiment
Influence of Temperature and Humidity on Contrail Formation Regions in EMAC: A Spring Case Study
Microphysical processes involving the vapour phase dominate in simulated low-level Arctic clouds
Understanding aerosol–cloud interactions using a single-column model for a cold-air outbreak case during the ACTIVATE campaign
The Critical Number and Size of Precipitation Embryos to Accelerate Warm Rain Initiation
On the sensitivity of aerosol–cloud interactions to changes in sea surface temperature in radiative–convective equilibrium
Exploring aerosol–cloud interactions in liquid-phase clouds over eastern China and its adjacent ocean using the WRF-Chem–SBM model
Impact on the stratocumulus-to-cumulus transition of the interaction of cloud microphysics and macrophysics with large-scale circulation
How the representation of microphysical processes affects tropical condensate in a global storm-resolving model
Finite domains cause bias in measured and modeled distributions of cloud sizes
A systematic evaluation of high-cloud controlling factors
August Mikkelsen, Daniel T. McCoy, Trude Eidhammer, Andrew Gettelman, Ci Song, Hamish Gordon, and Isabel L. McCoy
Atmos. Chem. Phys., 25, 4547–4570, https://doi.org/10.5194/acp-25-4547-2025, https://doi.org/10.5194/acp-25-4547-2025, 2025
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Whether increased aerosol increases or decreases liquid cloud mass has been a longstanding question. Observed correlations suggest that aerosols thin liquid cloud, but we are able to show that observations were consistent with an increase in liquid cloud in response to aerosols by leveraging a model where causality could be traced.
Tim Lüttmer, Peter Spichtinger, and Axel Seifert
Atmos. Chem. Phys., 25, 4505–4529, https://doi.org/10.5194/acp-25-4505-2025, https://doi.org/10.5194/acp-25-4505-2025, 2025
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We investigate ice formation pathways in idealized convective clouds using a novel microphysics scheme that distinguishes between five ice classes each with their own unique formation mechanism. Ice crystals from rime splintering form the lowermost layer of ice crystals around the updraft core. The majority of ice crystals in the anvil of the convective cloud stems from frozen droplets. Ice stemming from homogeneous and deposition nucleation was only relevant in the overshoot.
Fan Yang, Hamed Fahandezh Sadi, Raymond A. Shaw, Fabian Hoffmann, Pei Hou, Aaron Wang, and Mikhail Ovchinnikov
Atmos. Chem. Phys., 25, 3785–3806, https://doi.org/10.5194/acp-25-3785-2025, https://doi.org/10.5194/acp-25-3785-2025, 2025
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Large-eddy simulations of a convection cloud chamber show two new microphysics regimes, cloud oscillation and cloud collapse, due to haze–cloud interactions. Our results suggest that haze particles and their interactions with cloud droplets should be considered especially in polluted conditions. To properly simulate haze–cloud interactions, we need to resolve droplet activation and deactivation processes, instead of using Twomey-type activation parameterization.
Shiye Huang, Jing Yang, Jiaojiao Li, Qian Chen, Qilin Zhang, and Fengxia Guo
Atmos. Chem. Phys., 25, 1831–1850, https://doi.org/10.5194/acp-25-1831-2025, https://doi.org/10.5194/acp-25-1831-2025, 2025
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Aerosol and secondary ice production are both vital to charge separation in thunderstorms, but the relative importance of different SIP processes to cloud electrification under different aerosol conditions is not well understood. In this study, we show in a clean environment, the shattering of freezing drops has the greatest effect on the charging rate, while in a polluted environment, both rime splintering and the shattering of freezing drops have a significant effect on cloud electrification.
Meilian Chen, Xiaoqin Jing, Jiaojiao Li, Jing Yang, Xiaobo Dong, Bart Geerts, Yan Yin, Baojun Chen, Lulin Xue, Mengyu Huang, Ping Tian, and Shaofeng Hua
EGUsphere, https://doi.org/10.5194/egusphere-2025-47, https://doi.org/10.5194/egusphere-2025-47, 2025
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Several recent studies have reported complete cloud glaciation induced by airborne-based glaciogenic cloud seeding over plains. Since turbulence is an important factor to maintain clouds in mixed-phase, it is hypothesized that turbulence may have an impact on the seeding effect. This hypothesis is evident in the present study, which shows turbulence can accelerate the impact of airborne glaciogenic seeding of stratiform clouds.
Harri Kokkola, Juha Tonttila, Silvia M. Calderón, Sami Romakkaniemi, Antti Lipponen, Aapo Peräkorpi, Tero Mielonen, Edward Gryspeerdt, Timo Henrik Virtanen, Pekka Kolmonen, and Antti Arola
Atmos. Chem. Phys., 25, 1533–1543, https://doi.org/10.5194/acp-25-1533-2025, https://doi.org/10.5194/acp-25-1533-2025, 2025
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Understanding how atmospheric aerosols affect clouds is a scientific challenge. One question is how aerosols affects the amount of cloud water. We used a cloud-scale model to study these effects on marine clouds. The study showed that variations in cloud properties and instrument noise can cause bias in satellite-derived cloud water content. However, our results suggest that for similar weather conditions with well-defined aerosol concentrations, satellite data can reliably track these effects.
Franziska Hellmuth, Tim Carlsen, Anne Sophie Daloz, Robert Oscar David, Haochi Che, and Trude Storelvmo
Atmos. Chem. Phys., 25, 1353–1383, https://doi.org/10.5194/acp-25-1353-2025, https://doi.org/10.5194/acp-25-1353-2025, 2025
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This article compares the occurrence of supercooled liquid-containing clouds (sLCCs) and their link to surface snowfall in CloudSat–CALIPSO, ERA5, and the CMIP6 models. Significant discrepancies were found, with ERA5 and CMIP6 consistently overestimating sLCC and snowfall frequency. This bias is likely due to cloud microphysics parameterization. This conclusion has implications for accurately representing cloud phase and snowfall in future climate projections.
Guillaume Feger, Jean-Pierre Chaboureau, Thibaut Dauhut, Julien Delanoë, and Pierre Coutris
EGUsphere, https://doi.org/10.5194/egusphere-2025-105, https://doi.org/10.5194/egusphere-2025-105, 2025
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The Saharan air at trade wind layer, cold pools, and upper tropospheric dry air are identified as the three main factors inhibiting the cyclogenesis of the Pierre Henri mesoscale convective system. The findings were obtained trough observations made during two flights of the CADDIWA campaign and a convection-permitting simulation run with the Meso-NH model. They provide new insights into the complex dynamics of cyclogenesis in the Cape Verde region and challenge the existing model of the SAL.
Claudia Christine Stephan and Bjorn Stevens
Atmos. Chem. Phys., 25, 1209–1226, https://doi.org/10.5194/acp-25-1209-2025, https://doi.org/10.5194/acp-25-1209-2025, 2025
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Tropical precipitation cluster area and intensity distributions follow power laws, but the physical processes responsible for this behavior remain unknown. We analyze global simulations that realistically represent precipitation processes. We consider Earth-like planets as well as virtual planets to realize different types of large-scale dynamics. Our finding is that power laws in Earth’s precipitation cluster statistics stem from the robust power laws in Earth’s atmospheric wind field.
Wojciech W. Grabowski and Hanna Pawlowska
EGUsphere, https://doi.org/10.5194/egusphere-2024-4104, https://doi.org/10.5194/egusphere-2024-4104, 2025
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A simple diagram to depict cloud droplets formation via activation of cloud condensation nuclei (CCN) as well as their subsequent growth and evaporation is presented.
Seoung Soo Lee, Chang Hoon Jung, Jinho Choi, Young Jun Yoon, Junshik Um, Youtong Zheng, Jianping Guo, Manguttathil G. Manoj, Sang-Keun Song, and Kyung-Ja Ha
Atmos. Chem. Phys., 25, 705–726, https://doi.org/10.5194/acp-25-705-2025, https://doi.org/10.5194/acp-25-705-2025, 2025
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This study attempts to test a general factor that explains differences in the properties of different mixed-phase clouds using a modeling tool. Although this attempt is not to identify a factor that can perfectly explain and represent the properties of different mixed-phase clouds, we believe that this attempt acts as a valuable stepping stone towards a more complete, general way of using climate models to better predict climate change.
Wenjie Zhang, Hong Wang, Xiaoye Zhang, Yue Peng, Zhaodong Liu, Deying Wang, Da Zhang, Chen Han, Yang Zhao, Junting Zhong, Wenxing Jia, Huiqiong Ning, and Huizheng Che
EGUsphere, https://doi.org/10.5194/egusphere-2024-3677, https://doi.org/10.5194/egusphere-2024-3677, 2025
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We implement a real-time subgrid-scale aerosol-cloud interaction (ACI) mechanism in a mesoscale atmospheric chemistry system and find that subgrid-scale ACI can improve meteorological factors predictions. This study demonstrates the importance of real-time subgrid-scale ACI to weather forecast and the necessity of multiscale ACI studies.
Kevin Wolf, Nicolas Bellouin, Olivier Boucher, Susanne Rohs, and Yun Li
Atmos. Chem. Phys., 25, 157–181, https://doi.org/10.5194/acp-25-157-2025, https://doi.org/10.5194/acp-25-157-2025, 2025
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ERA5 atmospheric reanalysis and airborne in situ observations from IAGOS are compared in terms of the representation of the contrail formation potential and the presence of supersaturation. Differences are traced back to biases in ERA5 relative humidity fields. Those biases are addressed by applying a quantile mapping technique that significantly improved contrail estimation based on post-processed ERA5 data.
Marje Prank, Juha Tonttila, Xiaoxia Shang, Sami Romakkaniemi, and Tomi Raatikainen
Atmos. Chem. Phys., 25, 183–197, https://doi.org/10.5194/acp-25-183-2025, https://doi.org/10.5194/acp-25-183-2025, 2025
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Large primary bioparticles such as pollen can be abundant in the atmosphere. In humid conditions pollen can rupture and release a large number of fine sub-pollen particles (SPPs). The paper investigates what kind of birch pollen concentrations are needed for the pollen and SPPs to start playing a noticeable role in cloud processes and alter precipitation formation. In the studied cases only the largest observed pollen concentrations were able to noticeably alter the precipitation formation.
Luís Filipe Escusa dos Santos, Hannah C. Frostenberg, Alejandro Baró Pérez, Annica M. L. Ekman, Luisa Ickes, and Erik S. Thomson
Atmos. Chem. Phys., 25, 119–142, https://doi.org/10.5194/acp-25-119-2025, https://doi.org/10.5194/acp-25-119-2025, 2025
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The Arctic is experiencing enhanced surface warming. The observed decline in Arctic sea-ice extent is projected to lead to an increase in Arctic shipping activity, which may lead to further climatic feedbacks. Using an atmospheric model and results from marine engine experiments that focused on fuel sulfur content reduction and exhaust wet scrubbing, we investigate how ship exhaust particles influence the properties of Arctic clouds. Implications for radiative surface processes are discussed.
Nadja Omanovic, Brigitta Goger, and Ulrike Lohmann
Atmos. Chem. Phys., 24, 14145–14175, https://doi.org/10.5194/acp-24-14145-2024, https://doi.org/10.5194/acp-24-14145-2024, 2024
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We evaluated the numerical weather model ICON in two horizontal resolutions with two bulk microphysics schemes over hilly and complex terrain in Switzerland and Austria, respectively. We focused on the model's ability to simulate mid-level clouds in summer and winter. By combining observational data from two different field campaigns, we show that an increase in the horizontal resolution and a more advanced cloud microphysics scheme is strongly beneficial for cloud representation.
Cornelis Schwenk and Annette Miltenberger
Atmos. Chem. Phys., 24, 14073–14099, https://doi.org/10.5194/acp-24-14073-2024, https://doi.org/10.5194/acp-24-14073-2024, 2024
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Warm conveyor belts (WCBs) transport moisture into the upper atmosphere, where it acts as a greenhouse gas. This transport is not well understood, and the role of rapidly rising air is unclear. We simulate a WCB and look at fast- and slow-rising air to see how moisture is (differently) transported. We find that for fast-ascending air more ice particles reach higher into the atmosphere and that frozen cloud particles are removed differently than during slow ascent, which has more water vapour.
Yao-Sheng Chen, Prasanth Prabhakaran, Fabian Hoffmann, Jan Kazil, Takanobu Yamaguchi, and Graham Feingold
EGUsphere, https://doi.org/10.5194/egusphere-2024-3891, https://doi.org/10.5194/egusphere-2024-3891, 2024
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Injecting sea salt aerosols into marine stratiform clouds can distribute the cloud water over more droplets in smaller sizes. This process is expected to make the clouds brighter, allowing them to reflect more sunlight back to space. However, it may also cause the clouds to lose water over time, reducing their ability to reflect sunlight. We use a computer model to show that the loss of cloud water occurs relatively quickly and does not completely offset the initial brightening.
Fabian Hoffmann, Yao-Sheng Chen, and Graham Feingold
EGUsphere, https://doi.org/10.5194/egusphere-2024-3893, https://doi.org/10.5194/egusphere-2024-3893, 2024
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Clouds reflect a substantial portion of the incoming solar radiation back into space. This capacity is determined by the number of cloud droplets, which in turn is influenced by the number of aerosol particles, forming the basis for aerosol-cloud-climate interactions. In this study, we use a simple mixed-layer approach to understand the effect of aerosol on cloud water in non-precipitating stratocumulus.
Jing Yang, Jiaojiao Li, Meilian Chen, Xiaoqin Jing, Yan Yin, Bart Geerts, Zhien Wang, Yubao Liu, Baojun Chen, Shaofeng Hua, Hao Hu, Xiaobo Dong, Ping Tian, Qian Chen, and Yang Gao
Atmos. Chem. Phys., 24, 13833–13848, https://doi.org/10.5194/acp-24-13833-2024, https://doi.org/10.5194/acp-24-13833-2024, 2024
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Detecting unambiguous signatures is vital for examining cloud-seeding impacts, but often, seeding signatures are immersed in natural variability. In this study, reflectivity changes induced by glaciogenic seeding using different AgI concentrations are investigated under various conditions, and a method is developed to estimate the AgI concentration needed to detect unambiguous seeding signatures. The results aid in operational seeding-based decision-making regarding the amount of AgI dispersed.
Konstantinos Kourtidis, Stavros Stathopoulos, and Vassilis Amiridis
EGUsphere, https://doi.org/10.5194/egusphere-2024-3314, https://doi.org/10.5194/egusphere-2024-3314, 2024
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The loud sound of thunder will induce mechanical effects on cloud droplets and ice particles, causing changes in their size distribution.
Florian Sauerland, Niels Souverijns, Anna Possner, Heike Wex, Preben Van Overmeiren, Alexander Mangold, Kwinten Van Weverberg, and Nicole van Lipzig
Atmos. Chem. Phys., 24, 13751–13768, https://doi.org/10.5194/acp-24-13751-2024, https://doi.org/10.5194/acp-24-13751-2024, 2024
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We use a regional climate model, COSMO-CLM², enhanced with a module resolving aerosol processes, to study Antarctic clouds. We prescribe different concentrations of ice-nucleating particles to our model to assess how these clouds respond to concentration changes, validating results with cloud and aerosol observations from the Princess Elisabeth Antarctica station. Our results show that aerosol–cloud interactions vary with temperature, providing valuable insights into Antarctic cloud dynamics.
Yi Li, Xiaoli Liu, and Hengjia Cai
Atmos. Chem. Phys., 24, 13525–13540, https://doi.org/10.5194/acp-24-13525-2024, https://doi.org/10.5194/acp-24-13525-2024, 2024
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The influence of different aerosol modes on cloud processes remains controversial. We modified the aerosol spectra and concentrations to simulate a warm stratiform cloud process in Jiangxi, China, using the WRF-SBM scheme. Research shows that different aerosol spectra have diverse effects on cloud droplet spectra, cloud development, and the correlation between dispersion (ε) and cloud physics quantities. Compared to cloud droplet concentration, ε is more sensitive to the volume radius.
Fabian Hoffmann, Franziska Glassmeier, and Graham Feingold
Atmos. Chem. Phys., 24, 13403–13412, https://doi.org/10.5194/acp-24-13403-2024, https://doi.org/10.5194/acp-24-13403-2024, 2024
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Clouds constitute a major cooling influence on Earth's climate system by reflecting a large fraction of the incident solar radiation back to space. This ability is controlled by the number of cloud droplets, which is governed by the number of aerosol particles in the atmosphere, laying the foundation for so-called aerosol–cloud–climate interactions. In this study, a simple model to understand the effect of aerosol on cloud water is developed and applied.
Pouriya Alinaghi, Fredrik Jansson, Daniel A. Blázquez, and Franziska Glassmeier
EGUsphere, https://doi.org/10.5194/egusphere-2024-3501, https://doi.org/10.5194/egusphere-2024-3501, 2024
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Shallow clouds in the trades are a major source of uncertainty in climate projections. These clouds organize into striking mesoscale patterns that are exactly what climate models lack. This study explores the origin of such patterns and investigates how variations in microscale properties control them. The importance of microscale effects is compared to that of large-scale forcing on the mesoscale organization of trade-cumulus fields.
Andrea Mosso, Thomas Hocking, and Thorsten Mauritsen
Atmos. Chem. Phys., 24, 12793–12806, https://doi.org/10.5194/acp-24-12793-2024, https://doi.org/10.5194/acp-24-12793-2024, 2024
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Clouds play a crucial role in the Earth's energy balance, as they can either warm up or cool down the area they cover depending on their height and depth. They are expected to alter their behaviour under climate change, affecting the warming generated by greenhouse gases. This paper proposes a new method to estimate their overall effect on this warming by simulating a climate where clouds are transparent. Results show that with the model used, clouds have a stabilising effect on climate.
Tao Shi, Yuanjian Yang, Ping Qi, and Simone Lolli
Atmos. Chem. Phys., 24, 12807–12822, https://doi.org/10.5194/acp-24-12807-2024, https://doi.org/10.5194/acp-24-12807-2024, 2024
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This paper explored the formation mechanisms of the amplified canopy urban heat island intensity (ΔCUHII) during heat wave (HW) periods in the megacity of Beijing from the perspectives of mountain–valley breeze and urban morphology. During the mountain breeze phase, high-rise buildings with lower sky view factors (SVFs) had a pronounced effect on the ΔCUHII. During the valley breeze phase, high-rise buildings exerted a dual influence on the ΔCUHII.
Yao-Sheng Chen, Jianhao Zhang, Fabian Hoffmann, Takanobu Yamaguchi, Franziska Glassmeier, Xiaoli Zhou, and Graham Feingold
Atmos. Chem. Phys., 24, 12661–12685, https://doi.org/10.5194/acp-24-12661-2024, https://doi.org/10.5194/acp-24-12661-2024, 2024
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Marine stratocumulus cloud is a type of shallow cloud that covers the vast areas of Earth's surface. It plays an important role in Earth's energy balance by reflecting solar radiation back to space. We used numerical models to simulate a large number of marine stratocumuli with different characteristics. We found that how the clouds develop throughout the day is affected by the level of humidity in the air above the clouds and how closely the clouds connect to the ocean surface.
Andrew DeLaFrance, Lynn McMurdie, Angela Rowe, and Andrew Heymsfield
EGUsphere, https://doi.org/10.5194/egusphere-2024-3423, https://doi.org/10.5194/egusphere-2024-3423, 2024
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Numerical modeling simulations are used to investigate ice crystal growth and decay processes within a banded region of enhanced precipitation rates during a prominent winter storm. We identify robust primary ice growth in the upper portion of the cloud but decay exceeding 70 % during fallout through a subsaturated layer. The ice fall characteristics and decay rate are sensitive to the ambient cloud properties which has implications for radar-based measurements and precipitation accumulations.
Nathan H. Pope and Adele L. Igel
EGUsphere, https://doi.org/10.5194/egusphere-2024-3214, https://doi.org/10.5194/egusphere-2024-3214, 2024
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We used PAFOG, an atmospheric model that simulates a single column, to study the sensitivity of marine fog formed through the lowering of the base of a stratus cloud to meteorology and aerosols. We found that higher aerosol concentration reduces the likelihood and duration of fog, but leads to denser fog. This overall trend was caused by multiple physical mechanisms depending on conditions.
Hsiang-He Lee, Xue Zheng, Shaoyue Qiu, and Yuan Wang
EGUsphere, https://doi.org/10.5194/egusphere-2024-3199, https://doi.org/10.5194/egusphere-2024-3199, 2024
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The study investigates how aerosol-cloud interactions affect warm boundary layer stratiform clouds over the Eastern North Atlantic. High-resolution WRF-Chem simulations reveal that non-rain clouds at the edges of cloud systems are prone to evaporation, leading to an aerosol drying effect and a transition of aerosols back to accumulation mode for future activation. The study emphasizes that this dynamic behavior is often not adequately represented in most previous prescribed-aerosol simulations.
Alexei Korolev, Zhipeng Qu, Jason Milbrandt, Ivan Heckman, Mélissa Cholette, Mengistu Wolde, Cuong Nguyen, Greg M. McFarquhar, Paul Lawson, and Ann M. Fridlind
Atmos. Chem. Phys., 24, 11849–11881, https://doi.org/10.5194/acp-24-11849-2024, https://doi.org/10.5194/acp-24-11849-2024, 2024
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The phenomenon of high ice water content (HIWC) occurs in mesoscale convective systems (MCSs) when a large number of small ice particles with typical sizes of a few hundred micrometers is found at high altitudes. It was found that secondary ice production in the vicinity of the melting layer plays a key role in the formation and maintenance of HIWC. This study presents a conceptual model of the formation of HIWC in tropical MCSs based on in situ observations and numerical simulation.
Puja Roy, Robert M. Rauber, and Larry Di Girolamo
Atmos. Chem. Phys., 24, 11653–11678, https://doi.org/10.5194/acp-24-11653-2024, https://doi.org/10.5194/acp-24-11653-2024, 2024
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Cloud droplet temperature and lifetime impact cloud microphysical processes such as the activation of ice-nucleating particles. We investigate the thermal and radial evolution of supercooled cloud droplets and their surrounding environments with an aim to better understand observed enhanced ice formation at supercooled cloud edges. This analysis shows that the magnitude of droplet cooling during evaporation is greater than estimated from past studies, especially for drier environments.
Mathieu Lachapelle, Mélissa Cholette, and Julie M. Thériault
Atmos. Chem. Phys., 24, 11285–11304, https://doi.org/10.5194/acp-24-11285-2024, https://doi.org/10.5194/acp-24-11285-2024, 2024
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Hazardous precipitation types such as ice pellets and freezing rain are difficult to predict because they are associated with complex microphysical processes. Using Predicted Particle Properties (P3), this work shows that secondary ice production processes increase the amount of ice pellets simulated while decreasing the amount of freezing rain. Moreover, the properties of the simulated precipitation compare well with those that were measured.
Andrew DeLaFrance, Lynn A. McMurdie, Angela K. Rowe, and Andrew J. Heymsfield
Atmos. Chem. Phys., 24, 11191–11206, https://doi.org/10.5194/acp-24-11191-2024, https://doi.org/10.5194/acp-24-11191-2024, 2024
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Using a numerical model, the process whereby falling ice crystals accumulate supercooled liquid water droplets is investigated to elucidate its effects on radar-based measurements and surface precipitation. We demonstrate that this process accounted for 55% of the precipitation during a wintertime storm and is uniquely discernable from other ice crystal growth processes in Doppler velocity measurements. These results have implications for measurements from airborne and spaceborne platforms.
Gabriella Wallentin, Annika Oertel, Luisa Ickes, Peggy Achtert, Matthias Tesche, and Corinna Hoose
EGUsphere, https://doi.org/10.5194/egusphere-2024-2988, https://doi.org/10.5194/egusphere-2024-2988, 2024
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Multilayer clouds are common in the Arctic but remain understudied. We use an atmospheric model to simulate multilayer cloud cases from the Arctic expedition MOSAiC 2019/2020. We find that it is complex to accurately model these cloud layers due to the lack of correct temperature and humidity profiles. The model also struggles to capture the observed cloud phase, the relative concentration of cloud droplets and cloud ice. We constrain our model to measured aerosols to mitigate this issue.
Toshi Matsui, Daniel Hernandez-Deckers, Scott E. Giangrande, Thiago S. Biscaro, Ann Fridlind, and Scott Braun
Atmos. Chem. Phys., 24, 10793–10814, https://doi.org/10.5194/acp-24-10793-2024, https://doi.org/10.5194/acp-24-10793-2024, 2024
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Using computer simulations and real measurements, we discovered that storms over the Amazon were narrower but more intense during the dry periods, producing heavier rain and more ice particles in the clouds. Our research showed that cumulus bubbles played a key role in creating these intense storms. This study can improve the representation of the effect of continental and ocean environments on tropical regions' rainfall patterns in simulations.
Ravi Kumar Reddy Addula, Ingrid de Almeida Ribeiro, Valeria Molinero, and Baron Peters
Atmos. Chem. Phys., 24, 10833–10848, https://doi.org/10.5194/acp-24-10833-2024, https://doi.org/10.5194/acp-24-10833-2024, 2024
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Ice nucleation from supercooled droplets is important in many weather and climate modeling efforts. For experiments where droplets are steadily supercooled from the freezing point, our work combines nucleation theory and survival probability analysis to predict the nucleation spectrum, i.e., droplet freezing probabilities vs. temperature. We use the new framework to extract approximately consistent rate parameters from experiments with different cooling rates and droplet sizes.
Jianhao Zhang, Yao-Sheng Chen, Takanobu Yamaguchi, and Graham Feingold
Atmos. Chem. Phys., 24, 10425–10440, https://doi.org/10.5194/acp-24-10425-2024, https://doi.org/10.5194/acp-24-10425-2024, 2024
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Quantifying cloud response to aerosol perturbations presents a major challenge in understanding the human impact on climate. Using a large number of process-resolving simulations of marine stratocumulus, we show that solar heating drives a negative feedback mechanism that buffers the persistent negative trend in cloud water adjustment after sunrise. This finding has implications for the dependence of the cloud cooling effect on the timing of deliberate aerosol perturbations.
Aaron Wang, Steve Krueger, Sisi Chen, Mikhail Ovchinnikov, Will Cantrell, and Raymond A. Shaw
Atmos. Chem. Phys., 24, 10245–10260, https://doi.org/10.5194/acp-24-10245-2024, https://doi.org/10.5194/acp-24-10245-2024, 2024
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We employ two methods to examine a laboratory experiment on clouds with both ice and liquid phases. The first assumes well-mixed properties; the second resolves the spatial distribution of turbulence and cloud particles. Results show that while the trends in mean properties generally align, when turbulence is resolved, liquid droplets are not fully depleted by ice due to incomplete mixing. This underscores the threshold of ice mass fraction in distinguishing mixed-phase clouds from ice clouds.
Patrick Peter, Sigrun Matthes, Christine Frömming, Patrick Jöckel, Luca Bugliaro, Andreas Giez, Martina Krämer, and Volker Grewe
EGUsphere, https://doi.org/10.5194/egusphere-2024-2142, https://doi.org/10.5194/egusphere-2024-2142, 2024
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Our study examines how temperature and humidity representations influence contrail (-cirrus) formation criteria. Using various model setups, we identified biases that lead to overestimation of contrail formation areas. By comparing simulations with in-flight and satellite observations, we confirmed that humidity threshold choices greatly affect contrail predictions. These findings can help develop strategies for climate-optimized flight routes, potentially reducing aviation's climate effect.
Theresa Kiszler, Davide Ori, and Vera Schemann
Atmos. Chem. Phys., 24, 10039–10053, https://doi.org/10.5194/acp-24-10039-2024, https://doi.org/10.5194/acp-24-10039-2024, 2024
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Microphysical processes impact the phase-partitioning of clouds. In this study we evaluate these processes while focusing on low-level Arctic clouds. To achieve this we used an extensive simulation set in combination with a new diagnostic tool. This study presents our findings on the relevance of these processes and their behaviour under different thermodynamic regimes.
Shuaiqi Tang, Hailong Wang, Xiang-Yu Li, Jingyi Chen, Armin Sorooshian, Xubin Zeng, Ewan Crosbie, Kenneth L. Thornhill, Luke D. Ziemba, and Christiane Voigt
Atmos. Chem. Phys., 24, 10073–10092, https://doi.org/10.5194/acp-24-10073-2024, https://doi.org/10.5194/acp-24-10073-2024, 2024
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We examined marine boundary layer clouds and their interactions with aerosols in the E3SM single-column model (SCM) for a case study. The SCM shows good agreement when simulating the clouds with high-resolution models. It reproduces the relationship between cloud droplet and aerosol particle number concentrations as produced in global models. However, the relationship between cloud liquid water and droplet number concentration is different, warranting further investigation.
Jung-Sub Lim, Yign Noh, Hyunho Lee, and Fabian Hoffmann
EGUsphere, https://doi.org/10.5194/egusphere-2024-2636, https://doi.org/10.5194/egusphere-2024-2636, 2024
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The onset of rain is not fully understood. In this study, we address the impact of comparably large particles (precipitation embryos), speculated to initiate rain in clouds that do not contain ice. We showed that these particles can accelerate rain initiation only if their size and number exceed a threshold. As this threshold depends on the cloud's micro- and macrostructure, the impact of large particles on rain initiation is situation-dependent.
Suf Lorian and Guy Dagan
Atmos. Chem. Phys., 24, 9323–9338, https://doi.org/10.5194/acp-24-9323-2024, https://doi.org/10.5194/acp-24-9323-2024, 2024
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We examine the combined effect of aerosols and sea surface temperature (SST) on clouds under equilibrium conditions in cloud-resolving radiative–convective equilibrium simulations. We demonstrate that the aerosol–cloud interaction's effect on top-of-atmosphere energy gain strongly depends on the underlying SST, while the shortwave part of the spectrum is significantly more sensitive to SST. Furthermore, increasing aerosols influences upper-troposphere stability and thus anvil cloud fraction.
Jianqi Zhao, Xiaoyan Ma, Johannes Quaas, and Hailing Jia
Atmos. Chem. Phys., 24, 9101–9118, https://doi.org/10.5194/acp-24-9101-2024, https://doi.org/10.5194/acp-24-9101-2024, 2024
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We explore aerosol–cloud interactions in liquid-phase clouds over eastern China and its adjacent ocean in winter based on the WRF-Chem–SBM model, which couples a spectral-bin microphysics scheme and an online aerosol module. Our study highlights the differences in aerosol–cloud interactions between land and ocean and between precipitation clouds and non-precipitation clouds, and it differentiates and quantifies their underlying mechanisms.
Je-Yun Chun, Robert Wood, Peter N. Blossey, and Sarah J. Doherty
EGUsphere, https://doi.org/10.5194/egusphere-2024-2439, https://doi.org/10.5194/egusphere-2024-2439, 2024
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This study explores how aerosols affect clouds transitioning from stratocumulus to cumulus along trade winds under varying atmospheric conditions. We found that aerosols typically reduce precipitation and raise cloud height, but their impact changes when subsidence changes by aerosol enhancement are considered. Our findings indicate that the cooling effect of aerosols might be overestimated if these atmospheric changes are not accounted for.
Ann Kristin Naumann, Monika Esch, and Bjorn Stevens
EGUsphere, https://doi.org/10.5194/egusphere-2024-2268, https://doi.org/10.5194/egusphere-2024-2268, 2024
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This study explores how uncertainties in the representation of microphysical processes affect the tropical condensate distribution in the global storm-resolving model ICON. The results point to the importance of the fall speed of hydrometeor particles and to a simple relationship: the faster a condensate falls, the less there is of it. Implications for the energy balance and precipitation properties are discussed.
Thomas D. DeWitt and Timothy J. Garrett
Atmos. Chem. Phys., 24, 8457–8472, https://doi.org/10.5194/acp-24-8457-2024, https://doi.org/10.5194/acp-24-8457-2024, 2024
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There is considerable disagreement on mathematical parameters that describe the number of clouds of different sizes as well as the size of the largest clouds. Both are key defining characteristics of Earth's atmosphere. A previous study provided an incorrect explanation for the disagreement. Instead, the disagreement may be explained by prior studies not properly accounting for the size of their measurement domain. We offer recommendations for how the domain size can be accounted for.
Sarah Wilson Kemsley, Paulo Ceppi, Hendrik Andersen, Jan Cermak, Philip Stier, and Peer Nowack
Atmos. Chem. Phys., 24, 8295–8316, https://doi.org/10.5194/acp-24-8295-2024, https://doi.org/10.5194/acp-24-8295-2024, 2024
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Aiming to inform parameter selection for future observational constraint analyses, we incorporate five candidate meteorological drivers specifically targeting high clouds into a cloud controlling factor framework within a range of spatial domain sizes. We find a discrepancy between optimal domain size for predicting locally and globally aggregated cloud radiative anomalies and identify upper-tropospheric static stability as an important high-cloud controlling factor.
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Short summary
We address the phenomenon of ice enhancement in the vicinity of warm hydrometeors using highly accurate flow simulation techniques. It is found that the transiently supersaturated zones induced by the hydrometeor's wake are by far larger than what has been previously estimated. The ice enhancement is quantified on the micro- and macroscale, and its relevance is discussed. The results provided may contribute to a (currently unavailable) parametrization of the phenomenon.
We address the phenomenon of ice enhancement in the vicinity of warm hydrometeors using highly...
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