Articles | Volume 25, issue 9
https://doi.org/10.5194/acp-25-4867-2025
© Author(s) 2025. 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-25-4867-2025
© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
09 May 2025
Research article |
| 09 May 2025
| 09 May 2025
Impact of wildfire smoke on Arctic cirrus formation – Part 2: Simulation of MOSAiC 2019–2020 cases
Leibniz Institute for Tropospheric Research, Leipzig, Germany
Cristofer Jimenez
Leibniz Institute for Tropospheric Research, Leipzig, Germany
Daniel A. Knopf
School of Marine and Atmospheric Sciences, Stony Brook University, Stony Brook, NY 11794, USA
Johanna Roschke
Leibniz Institute for Tropospheric Research, Leipzig, Germany
Johannes Bühl
Leibniz Institute for Tropospheric Research, Leipzig, Germany
Harz University of Applied Sciences, Wernigerode, Germany
Kevin Ohneiser
Leibniz Institute for Tropospheric Research, Leipzig, Germany
Ronny Engelmann
Leibniz Institute for Tropospheric Research, Leipzig, Germany
Related authors
Athena Augusta Floutsi, Konstantinos Rizos, Dimitri Trapon, Ronny Engelmann, Dietrich Althausen, Eleni Marinou, Peristera Paschou, Julian Hofer, Emmanouil Proestakis, Henriette Gebauer, Annett Skupin, Albert Ansmann, Thorsten Fehr, Timon Hummel, Rob Koopman, Vassilis Amiridis, Ulla Wandinger, and Holger Baars
Atmos. Meas. Tech., 19, 1901–1925, https://doi.org/10.5194/amt-19-1901-2026, https://doi.org/10.5194/amt-19-1901-2026, 2026
Short summary
Short summary
We assess the representativeness of a remote ground-based station in Mindelo, Cabo Verde by utilizing continuous observations of a ground-based multiwavelength polarization Raman lidar and the LIdar climatology of Vertical Aerosol Structure (LIVAS) products. Based on a statistical analysis of the optical properties at different radii around Mindelo and case studies, we conclude that overall, the ground-based station in Mindelo can be considered conditionally representative.
Kangwen Sun, Guangyao Dai, Dimitri Trapon, Holger Baars, Albert Ansmann, Ulla Wandinger, and Songhua Wu
EGUsphere, https://doi.org/10.5194/egusphere-2026-596, https://doi.org/10.5194/egusphere-2026-596, 2026
This preprint is open for discussion and under review for Atmospheric Chemistry and Physics (ACP).
Short summary
Short summary
Targeting a large-scale smoke transport from the western US to Europe in September 2020 a smoke dataset was constructed based on Aeolus observations, in synergy with multi-platform data. The selected cross-sections show the vertical structure of the smoke layers at different transport phases. Statistical analyses of the complete dataset reveal the evolution of the smoke plume throughout its transatlantic transport.
Albert Ansmann, Julian Hofer, Rodanthi-Elisavet Mamouri, Moritz Haarig, Holger Baars, and Ulla Wandinger
EGUsphere, https://doi.org/10.5194/egusphere-2026-648, https://doi.org/10.5194/egusphere-2026-648, 2026
This preprint is open for discussion and under review for Atmospheric Measurement Techniques (AMT).
Short summary
Short summary
Updated lidar and ceilometer conversion factors are presented. The conversion factors allow us to calculate microphyscial properties from measurned optical properties. One the main goals is to support 355 nm lidar observations performed in the framwork of ESA's EarthCARE mission.
Yonatan Peleg, Lior Zeida-Cohen, Imri Tzror, Johannes Bühl, Albert Ansmann, Alexandra Chudnovsky, and Zohar Yakhini
EGUsphere, https://doi.org/10.5194/egusphere-2025-5215, https://doi.org/10.5194/egusphere-2025-5215, 2026
This preprint is open for discussion and under review for Atmospheric Measurement Techniques (AMT).
Short summary
Short summary
Mapping the vertical structure of aerosols and clouds is vital for climate science. We developed an AI model that reconstructs full atmospheric profiles from standard lidar data, even above signal attenuation. It accurately classifies aerosol and cloud types, capturing key atmospheric features. This cost-effective approach extends beyond sparse Cloudnet sites, enhancing monitoring and supporting improved weather and climate models.
Hannes Jascha Griesche, Ronny Engelmann, Martin Radenz, Julian Hofer, Dietrich Althausen, Albert Ansmann, Kevin Barry, Jessie Creamean, Cristofer Jimenez, and Patric Seifert
EGUsphere, https://doi.org/10.5194/egusphere-2025-5708, https://doi.org/10.5194/egusphere-2025-5708, 2025
Short summary
Short summary
A full annual cycle of mixed-phase ice-formation temperatures in the high Arctic is presented. Ship-based remote sensing with lidar and cloud radar from the Arctic expedition MOSAiC was used to investigate the impact of surface processes on mixed-phase cloud properties. Surface mixed-layer cloud coupling was derived base on radiosonde profiles. Combined with INP filter samples, sea ice concentration and back-trajectory analysis an influence of surface processes on the cloud properties was found.
Kevin Ohneiser, Patric Seifert, Willi Schimmel, Fabian Senf, Tom Gaudek, Martin Radenz, Audrey Teisseire, Veronika Ettrichrätz, Teresa Vogl, Nina Maherndl, Nils Pfeifer, Jan Henneberger, Anna J. Miller, Nadja Omanovic, Christopher Fuchs, Huiying Zhang, Fabiola Ramelli, Robert Spirig, Anton Kötsche, Heike Kalesse-Los, Maximilian Maahn, Heather Corden, Alexis Berne, Majid Hajipour, Hannes Griesche, Julian Hofer, Ronny Engelmann, Annett Skupin, Albert Ansmann, and Holger Baars
Atmos. Chem. Phys., 25, 17363–17386, https://doi.org/10.5194/acp-25-17363-2025, https://doi.org/10.5194/acp-25-17363-2025, 2025
Short summary
Short summary
This study focuses on a seeder-feeder cloud system on 8 Jan 2024 in Eriswil, Switzerland. It is shown how the interaction of these cloud systems changes the cloud microphysical properties and the precipitation patterns. A big set of advanced remote-sensing techniques and retrieval algorithms are applied, so that a detailed view on the seeder-feeder cloud system is available. The gained knowledge can be used to improve weather models and weather forecasts.
Yun He, Goutam Choudhury, Matthias Tesche, Albert Ansmann, Fan Yi, Detlef Müller, and Zhenping Yin
Atmos. Meas. Tech., 18, 5669–5685, https://doi.org/10.5194/amt-18-5669-2025, https://doi.org/10.5194/amt-18-5669-2025, 2025
Short summary
Short summary
We present a global dataset of POlarization LIdar PHOtometer Networking (POLIPHON) dust conversion factors at 532 nm obtained using Aerosol RObotic NETwork (AERONET) observations at 137 sites for ice-nucleating particle (INP) and 123 sites for cloud condensation nucleation (CCN) calculations. We also conduct a comparison of dust CCN concentration profiles derived using both POLIPHON and the independent Optical Modelling of the CALIPSO Aerosol Microphysics (OMCAM) retrieval.
Cristofer Jimenez, Albert Ansmann, Kevin Ohneiser, Hannes Griesche, Ronny Engelmann, Martin Radenz, Julian Hofer, Dietrich Althausen, Daniel A. Knopf, Sandro Dahlke, Johannes Bühl, Holger Baars, Patric Seifert, and Ulla Wandinger
Atmos. Chem. Phys., 25, 12955–12981, https://doi.org/10.5194/acp-25-12955-2025, https://doi.org/10.5194/acp-25-12955-2025, 2025
Short summary
Short summary
We studied the water and ice phases of Arctic mixed-phase clouds (MPCs) using dual FOV polarization lidar and Doppler radar on board Polarstern during the MOSAiC expedition. Two long-lasting Arctic MPCs and year-round statistics show persistent droplet activation and dominant immersion freezing, indicating well-filled cloud condensation nuclei and ice-nucleating particle reservoirs. These findings help explain MPC longevity and may improve cloud life cycle representation in weather and climate models.
Tom Gaudek, Cristofer Jimenez, Kevin Ohneiser, Christopher Fuchs, Jan Henneberger, Johannes Bühl, Andi Klamt, Albert Ansmann, Ronny Engelmann, and Patric Seifert
EGUsphere, https://doi.org/10.5194/egusphere-2025-4105, https://doi.org/10.5194/egusphere-2025-4105, 2025
Short summary
Short summary
This study introduces the maximum diameter (Dmax) of precipitation particles measured by a two-dimensional video disdrometer (2DVD) as a novel parameter. Dmax is applied in a cloud seeding study during the Cloudlab campaign and, for the first time, in a MOSAiC case to evaluate the LIRAS-ice remote-sensing retrieval of in-cloud ice crystal size and number. Both quantities agreed well with the 2DVD measurements under ideal conditions, highlighting the potential of Dmax for precipitation studies.
Sofía Gómez Maqueo Anaya, Dietrich Althausen, Julian Hofer, Moritz Haarig, Ulla Wandinger, Bernd Heinold, Ina Tegen, Matthias Faust, Holger Baars, Albert Ansmann, Ronny Engelmann, Annett Skupin, Birgit Heese, and Kerstin Schepanski
Atmos. Chem. Phys., 25, 9737–9764, https://doi.org/10.5194/acp-25-9737-2025, https://doi.org/10.5194/acp-25-9737-2025, 2025
Short summary
Short summary
This study investigates how hematite in Sahara dust affects how dust particles interact with radiation. Using lidar data from Cabo Verde (2021–2022) and hematite content from atmospheric model simulations, the results show that a higher hematite fraction leads to a decrease in the particle backscattering coefficients in a spectrally different way. These findings can improve the representation of mineral dust in climate models, particularly regarding their radiative effect.
Gladiola Malollari, Albert Ansmann, Holger Baars, Cristofer Jimenez, Julian Hofer, Ronny Engelmann, Nathan Skupin, and Seit Shallari
Atmos. Meas. Tech., 18, 3937–3944, https://doi.org/10.5194/amt-18-3937-2025, https://doi.org/10.5194/amt-18-3937-2025, 2025
Short summary
Short summary
This study presents, for the first time, the uncertainty analysis of the Ångström exponent assumption on the full set of retrievable optical properties obtained with Raman lidar. A quantitative comparison between the pure rotational and vibrational–rotational Raman lidar approaches is presented. A minor impact of a wrong Ångström exponent on the determined aerosol optical properties is found.
Zhaolong Wu, Patric Seifert, Yun He, Holger Baars, Haoran Li, Cristofer Jimenez, Chengcai Li, and Albert Ansmann
Atmos. Meas. Tech., 18, 3611–3634, https://doi.org/10.5194/amt-18-3611-2025, https://doi.org/10.5194/amt-18-3611-2025, 2025
Short summary
Short summary
This study introduces a novel method to detect horizontally oriented ice crystals (HOICs) using two ground-based polarization lidars at different zenith angles, based on a yearlong dataset collected in Beijing. Combined with cloud radar and reanalysis data, the fine categorization results reveal HOICs occur in calm winds and moderately cold temperatures and are influenced by turbulence near cloud bases. The results enhance our understanding of cloud processes and improve atmospheric models.
Hossein Panahifar, Maria Poutli, George Kotsias, Argyro Nisantzi, Silas Michaelides, Diofantos Hadjimitsis, Patric Seifert, Albert Ansmann, and Rodanthi-Elisavet Mamouri
Int. Arch. Photogramm. Remote Sens. Spatial Inf. Sci., XLVIII-G-2025, 1153–1158, https://doi.org/10.5194/isprs-archives-XLVIII-G-2025-1153-2025, https://doi.org/10.5194/isprs-archives-XLVIII-G-2025-1153-2025, 2025
Moritz Haarig, Ronny Engelmann, Holger Baars, Benedikt Gast, Dietrich Althausen, and Albert Ansmann
Atmos. Chem. Phys., 25, 7741–7763, https://doi.org/10.5194/acp-25-7741-2025, https://doi.org/10.5194/acp-25-7741-2025, 2025
Short summary
Short summary
The lidar ratio is an important quantity in aerosol typing. Its spectral slope contains information about the source region or transport paths of the observed aerosol. The extension to 1064 nm is a recent development led by our institute. We gathered previous observations and added new ones to provide the spectral slope for the most important aerosol types such as marine and continental aerosol, dust, smoke, and sulfate. We compared it to assumptions used for spaceborne backscatter lidars.
Albert Ansmann, Cristofer Jimenez, Johanna Roschke, Johannes Bühl, Kevin Ohneiser, Ronny Engelmann, Martin Radenz, Hannes Griesche, Julian Hofer, Dietrich Althausen, Daniel A. Knopf, Sandro Dahlke, Tom Gaudek, Patric Seifert, and Ulla Wandinger
Atmos. Chem. Phys., 25, 4847–4866, https://doi.org/10.5194/acp-25-4847-2025, https://doi.org/10.5194/acp-25-4847-2025, 2025
Short summary
Short summary
In this study, we focus on the potential impact of wildfire smoke on cirrus formation. For the first time, state-of-the-art aerosol and cirrus observations with lidar and radar, presented in this paper (Part 1 of a series of two articles), are closely linked to the comprehensive modeling of gravity-wave-induced ice nucleation in cirrus evolution processes, presented in a companion paper (Part 2). We found a clear impact of wildfire smoke on cirrus evolution.
Benedikt Gast, Cristofer Jimenez, Albert Ansmann, Moritz Haarig, Ronny Engelmann, Felix Fritzsch, Athena A. Floutsi, Hannes Griesche, Kevin Ohneiser, Julian Hofer, Martin Radenz, Holger Baars, Patric Seifert, and Ulla Wandinger
Atmos. Chem. Phys., 25, 3995–4011, https://doi.org/10.5194/acp-25-3995-2025, https://doi.org/10.5194/acp-25-3995-2025, 2025
Short summary
Short summary
In this study, we discuss the enhanced detection capabilities of a fluorescence lidar in the case of optically thin aerosol layers in the upper troposphere and lower stratosphere (UTLS) region. Our results suggest that such thin aerosol layers are not so rare in the UTLS and can potentially trigger and impact cirrus cloud formation through heterogeneous ice nucleation. By altering the microphysical cloud properties, this could affect clouds' evolution and lifetime and thus their climate effect.
Silke Groß, Volker Freudenthaler, Moritz Haarig, Albert Ansmann, Carlos Toledano, David Mateos, Petra Seibert, Rodanthi-Elisavet Mamouri, Argyro Nisantzi, Josef Gasteiger, Maximilian Dollner, Anne Tipka, Manuel Schöberl, Marilena Teri, and Bernadett Weinzierl
Atmos. Chem. Phys., 25, 3191–3211, https://doi.org/10.5194/acp-25-3191-2025, https://doi.org/10.5194/acp-25-3191-2025, 2025
Short summary
Short summary
Aerosols contribute to the largest uncertainties in climate change predictions. The eastern Mediterranean is a hotspot for aerosols with natural and anthropogenic contributions. We present lidar measurements performed during A-LIFE (Absorbing aerosol layers in a changing climate: aging, lifetime and dynamics) to characterize aerosols and aerosol mixtures. We extend current lidar classification and separation schemes and compare them to classification schemes using different methods.
Henriette Gebauer, Athena Augusta Floutsi, Moritz Haarig, Martin Radenz, Ronny Engelmann, Dietrich Althausen, Annett Skupin, Albert Ansmann, Cordula Zenk, and Holger Baars
Atmos. Chem. Phys., 24, 5047–5067, https://doi.org/10.5194/acp-24-5047-2024, https://doi.org/10.5194/acp-24-5047-2024, 2024
Short summary
Short summary
Sulfate aerosol from the volcanic eruption at La Palma in 2021 was observed over Cabo Verde. We characterized the aerosol burden based on a case study of lidar and sun photometer observations. We compared the volcanic case to the typical background conditions (reference case) to quantify the volcanic pollution. We show the first ever measurements of the extinction coefficient, lidar ratio and depolarization ratio at 1064 nm for volcanic sulfate.
Sofía Gómez Maqueo Anaya, Dietrich Althausen, Matthias Faust, Holger Baars, Bernd Heinold, Julian Hofer, Ina Tegen, Albert Ansmann, Ronny Engelmann, Annett Skupin, Birgit Heese, and Kerstin Schepanski
Geosci. Model Dev., 17, 1271–1295, https://doi.org/10.5194/gmd-17-1271-2024, https://doi.org/10.5194/gmd-17-1271-2024, 2024
Short summary
Short summary
Mineral dust aerosol particles vary greatly in their composition depending on source region, which leads to different physicochemical properties. Most atmosphere–aerosol models consider mineral dust aerosols to be compositionally homogeneous, which ultimately increases model uncertainty. Here, we present an approach to explicitly consider the heterogeneity of the mineralogical composition for simulations of the Saharan atmospheric dust cycle with regard to dust transport towards the Atlantic.
Julian Hofer, Patric Seifert, J. Ben Liley, Martin Radenz, Osamu Uchino, Isamu Morino, Tetsu Sakai, Tomohiro Nagai, and Albert Ansmann
Atmos. Chem. Phys., 24, 1265–1280, https://doi.org/10.5194/acp-24-1265-2024, https://doi.org/10.5194/acp-24-1265-2024, 2024
Short summary
Short summary
An 11-year dataset of polarization lidar observations from Lauder, New Zealand / Aotearoa, was used to distinguish the thermodynamic phase of natural clouds. The cloud dataset was separated to assess the impact of air mass origin on the frequency of heterogeneous ice formation. Ice formation efficiency in clouds above Lauder was found to be lower than in the polluted Northern Hemisphere midlatitudes but higher than in very clean and pristine environments, such as Punta Arenas in southern Chile.
Rodanthi-Elisavet Mamouri, Albert Ansmann, Kevin Ohneiser, Daniel A. Knopf, Argyro Nisantzi, Johannes Bühl, Ronny Engelmann, Annett Skupin, Patric Seifert, Holger Baars, Dragos Ene, Ulla Wandinger, and Diofantos Hadjimitsis
Atmos. Chem. Phys., 23, 14097–14114, https://doi.org/10.5194/acp-23-14097-2023, https://doi.org/10.5194/acp-23-14097-2023, 2023
Short summary
Short summary
For the first time, rather clear evidence is found that wildfire smoke particles can trigger strong cirrus formation. This finding is of importance because intensive and large wildfires may occur increasingly often in the future as climate change proceeds. Based on lidar observations in Cyprus in autumn 2020, we provide detailed insight into the cirrus formation at the tropopause in the presence of aged wildfire smoke (here, 8–9 day old Californian wildfire smoke).
Albert Ansmann, Kevin Ohneiser, Ronny Engelmann, Martin Radenz, Hannes Griesche, Julian Hofer, Dietrich Althausen, Jessie M. Creamean, Matthew C. Boyer, Daniel A. Knopf, Sandro Dahlke, Marion Maturilli, Henriette Gebauer, Johannes Bühl, Cristofer Jimenez, Patric Seifert, and Ulla Wandinger
Atmos. Chem. Phys., 23, 12821–12849, https://doi.org/10.5194/acp-23-12821-2023, https://doi.org/10.5194/acp-23-12821-2023, 2023
Short summary
Short summary
The 1-year MOSAiC (2019–2020) expedition with the German ice breaker Polarstern was the largest polar field campaign ever conducted. The Polarstern, with our lidar aboard, drifted with the pack ice north of 85° N for more than 7 months (October 2019 to mid-May 2020). We measured the full annual cycle of aerosol conditions in terms of aerosol optical and cloud-process-relevant properties. We observed a strong contrast between polluted winter and clean summer aerosol conditions.
Ulla Wandinger, Athena Augusta Floutsi, Holger Baars, Moritz Haarig, Albert Ansmann, Anja Hünerbein, Nicole Docter, David Donovan, Gerd-Jan van Zadelhoff, Shannon Mason, and Jason Cole
Atmos. Meas. Tech., 16, 2485–2510, https://doi.org/10.5194/amt-16-2485-2023, https://doi.org/10.5194/amt-16-2485-2023, 2023
Short summary
Short summary
We introduce an aerosol classification model that has been developed for the Earth Clouds, Aerosols and Radiation Explorer (EarthCARE). The model provides a consistent description of microphysical, optical, and radiative properties of common aerosol types such as dust, sea salt, pollution, and smoke. It is used for aerosol classification and assessment of radiation effects based on the synergy of active and passive observations with lidar, imager, and radiometer of the multi-instrument platform.
Athena Augusta Floutsi, Holger Baars, Ronny Engelmann, Dietrich Althausen, Albert Ansmann, Stephanie Bohlmann, Birgit Heese, Julian Hofer, Thomas Kanitz, Moritz Haarig, Kevin Ohneiser, Martin Radenz, Patric Seifert, Annett Skupin, Zhenping Yin, Sabur F. Abdullaev, Mika Komppula, Maria Filioglou, Elina Giannakaki, Iwona S. Stachlewska, Lucja Janicka, Daniele Bortoli, Eleni Marinou, Vassilis Amiridis, Anna Gialitaki, Rodanthi-Elisavet Mamouri, Boris Barja, and Ulla Wandinger
Atmos. Meas. Tech., 16, 2353–2379, https://doi.org/10.5194/amt-16-2353-2023, https://doi.org/10.5194/amt-16-2353-2023, 2023
Short summary
Short summary
DeLiAn is a collection of lidar-derived aerosol intensive optical properties for several aerosol types, namely the particle linear depolarization ratio, the extinction-to-backscatter ratio (lidar ratio) and the Ångström exponent. The data collection is based on globally distributed, long-term, ground-based, multiwavelength, Raman and polarization lidar measurements and currently covers two wavelengths, 355 and 532 nm, for 13 aerosol categories ranging from basic aerosol types to mixtures.
Yun He, Zhenping Yin, Albert Ansmann, Fuchao Liu, Longlong Wang, Dongzhe Jing, and Huijia Shen
Atmos. Meas. Tech., 16, 1951–1970, https://doi.org/10.5194/amt-16-1951-2023, https://doi.org/10.5194/amt-16-1951-2023, 2023
Short summary
Short summary
With the AERONET database, this study derives dust-related conversion factors at oceanic sites used in the POLIPHON method, which can convert lidar-retrieved dust extinction to ice-nucleating particle (INP)- and cloud condensation nuclei (CCN)-relevant parameters. The particle linear depolarization ratio in the AERONET aerosol inversion product is used to identify dust data points. The derived conversion factors can be applied to inverse 3-D global distributions of dust-related INPCs and CCNCs.
Kevin Ohneiser, Albert Ansmann, Jonas Witthuhn, Hartwig Deneke, Alexandra Chudnovsky, Gregor Walter, and Fabian Senf
Atmos. Chem. Phys., 23, 2901–2925, https://doi.org/10.5194/acp-23-2901-2023, https://doi.org/10.5194/acp-23-2901-2023, 2023
Short summary
Short summary
This study shows that smoke layers can reach the tropopause via the self-lofting effect within 3–7 d in the absence of pyrocumulonimbus convection if the
aerosol optical thickness is larger than approximately 2 for a longer time period. When reaching the stratosphere, wildfire smoke can sensitively influence the stratospheric composition on a hemispheric scale and thus can affect the Earth’s climate and the ozone layer.
Albert Ansmann, Kevin Ohneiser, Alexandra Chudnovsky, Daniel A. Knopf, Edwin W. Eloranta, Diego Villanueva, Patric Seifert, Martin Radenz, Boris Barja, Félix Zamorano, Cristofer Jimenez, Ronny Engelmann, Holger Baars, Hannes Griesche, Julian Hofer, Dietrich Althausen, and Ulla Wandinger
Atmos. Chem. Phys., 22, 11701–11726, https://doi.org/10.5194/acp-22-11701-2022, https://doi.org/10.5194/acp-22-11701-2022, 2022
Short summary
Short summary
For the first time we present a systematic study on the impact of wildfire smoke on ozone depletion in the Arctic (2020) and Antarctic stratosphere (2020, 2021). Two major fire events in Siberia and Australia were responsible for the observed record-breaking stratospheric smoke pollution. Our analyses were based on lidar observations of smoke parameters (Polarstern, Punta Arenas) and NDACC Arctic and Antarctic ozone profiles as well as on Antarctic OMI satellite observations of column ozone.
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
Short summary
Short summary
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.
Kevin Ohneiser, Albert Ansmann, Bernd Kaifler, Alexandra Chudnovsky, Boris Barja, Daniel A. Knopf, Natalie Kaifler, Holger Baars, Patric Seifert, Diego Villanueva, Cristofer Jimenez, Martin Radenz, Ronny Engelmann, Igor Veselovskii, and Félix Zamorano
Atmos. Chem. Phys., 22, 7417–7442, https://doi.org/10.5194/acp-22-7417-2022, https://doi.org/10.5194/acp-22-7417-2022, 2022
Short summary
Short summary
We present and discuss 2 years of long-term lidar observations of the largest stratospheric perturbation by wildfire smoke ever observed. The smoke originated from the record-breaking Australian fires in 2019–2020 and affects climate conditions and even the ozone layer in the Southern Hemisphere. The obvious link between dense smoke occurrence in the stratosphere and strong ozone depletion found in the Arctic and in the Antarctic in 2020 can be regarded as a new aspect of climate change.
Goutam Choudhury, Albert Ansmann, and Matthias Tesche
Atmos. Chem. Phys., 22, 7143–7161, https://doi.org/10.5194/acp-22-7143-2022, https://doi.org/10.5194/acp-22-7143-2022, 2022
Short summary
Short summary
Lidars provide height-resolved type-specific aerosol properties and are key in studying vertically collocated aerosols and clouds. In this study, we compare the aerosol number concentrations derived from spaceborne lidar with the in situ flight measurements. Our results show a reasonable agreement between both datasets. Such an agreement has not been achieved yet. It shows the potential of spaceborne lidar in studying aerosol–cloud interactions, which is needed to improve our climate forecasts.
Igor Veselovskii, Qiaoyun Hu, Albert Ansmann, Philippe Goloub, Thierry Podvin, and Mikhail Korenskiy
Atmos. Chem. Phys., 22, 5209–5221, https://doi.org/10.5194/acp-22-5209-2022, https://doi.org/10.5194/acp-22-5209-2022, 2022
Short summary
Short summary
A remote sensing method based on fluorescence lidar measurements can detect and quantify the smoke content in the upper troposphere and inside cirrus clouds. Based on two case studies, we demonstrate that the fluorescence lidar technique provides the possibility to estimate the smoke surface area concentration within freshly formed cirrus layers. This value was used in a smoke ice nucleating particle parameterization scheme to predict ice crystal number concentrations in cirrus generation cells.
Michaël Sicard, Carmen Córdoba-Jabonero, María-Ángeles López-Cayuela, Albert Ansmann, Adolfo Comerón, María-Paz Zorzano, Alejandro Rodríguez-Gómez, and Constantino Muñoz-Porcar
Atmos. Chem. Phys., 22, 1921–1937, https://doi.org/10.5194/acp-22-1921-2022, https://doi.org/10.5194/acp-22-1921-2022, 2022
Short summary
Short summary
This paper completes the companion paper of Córdoba-Jabonero et al. (2021). We estimate the total direct radiative effect produced by mineral dust particles during the June 2019 mega-heatwave at two sites in Spain and Germany. The results show that the dust particles in the atmosphere contribute to cooling the surface (less radiation reaches the surface) and that the heatwave (parametrized by high surface and air temperatures) contributes to reducing this cooling.
Moritz Haarig, Albert Ansmann, Ronny Engelmann, Holger Baars, Carlos Toledano, Benjamin Torres, Dietrich Althausen, Martin Radenz, and Ulla Wandinger
Atmos. Chem. Phys., 22, 355–369, https://doi.org/10.5194/acp-22-355-2022, https://doi.org/10.5194/acp-22-355-2022, 2022
Short summary
Short summary
The irregular shape of dust particles makes it difficult to treat them correctly in optical models. Atmospheric measurements of dust optical properties are therefore of great importance. The present study increases the space of observed parameters from 355 and 532 nm towards 1064 nm, which is of special importance for large dust particles. The lidar ratio influenced by mineralogy and the depolarization ratio influenced by shape are measured for the first time at all three wavelengths.
Martin Radenz, Johannes Bühl, Patric Seifert, Holger Baars, Ronny Engelmann, Boris Barja González, Rodanthi-Elisabeth Mamouri, Félix Zamorano, and Albert Ansmann
Atmos. Chem. Phys., 21, 17969–17994, https://doi.org/10.5194/acp-21-17969-2021, https://doi.org/10.5194/acp-21-17969-2021, 2021
Short summary
Short summary
This study brings together long-term ground-based remote-sensing observations of mixed-phase clouds at three key locations of aerosol–cloud interactions in the Northern and Southern Hemisphere midlatitudes. The findings contribute several new aspects on the nature of the excess of supercooled liquid clouds in the Southern Hemisphere, such as a long-term lidar-based estimate of ice-nucleating particle profiles as well as the effects of boundary layer coupling and gravity waves on ice formation.
Sebastian Düsing, Albert Ansmann, Holger Baars, Joel C. Corbin, Cyrielle Denjean, Martin Gysel-Beer, Thomas Müller, Laurent Poulain, Holger Siebert, Gerald Spindler, Thomas Tuch, Birgit Wehner, and Alfred Wiedensohler
Atmos. Chem. Phys., 21, 16745–16773, https://doi.org/10.5194/acp-21-16745-2021, https://doi.org/10.5194/acp-21-16745-2021, 2021
Short summary
Short summary
The work deals with optical properties of aerosol particles in dried and atmospheric states. Based on two measurement campaigns in the rural background of central Europe, different measurement approaches were compared with each other, such as modeling based on Mie theory and direct in situ or remote sensing measurements. Among others, it was shown that the aerosol extinction-to-backscatter ratio is relative humidity dependent, and refinement with respect to the model input parameters is needed.
Kevin Ohneiser, Albert Ansmann, Alexandra Chudnovsky, Ronny Engelmann, Christoph Ritter, Igor Veselovskii, Holger Baars, Henriette Gebauer, Hannes Griesche, Martin Radenz, Julian Hofer, Dietrich Althausen, Sandro Dahlke, and Marion Maturilli
Atmos. Chem. Phys., 21, 15783–15808, https://doi.org/10.5194/acp-21-15783-2021, https://doi.org/10.5194/acp-21-15783-2021, 2021
Short summary
Short summary
The highlight of the lidar measurements during the 1-year MOSAiC (Multidisciplinary drifting Observatory for the Study of Arctic Climate) expedition of the German icebreaker Polarstern (October 2019–October 2020) was the detection of a persistent, 10 km deep Siberian wildfire smoke layer in the upper troposphere and lower stratosphere (UTLS) from about 7–8 km to 17–18 km height that could potentially have impacted the record-breaking ozone depletion over the Arctic in the spring of 2020.
Ronny Engelmann, Albert Ansmann, Kevin Ohneiser, Hannes Griesche, Martin Radenz, Julian Hofer, Dietrich Althausen, Sandro Dahlke, Marion Maturilli, Igor Veselovskii, Cristofer Jimenez, Robert Wiesen, Holger Baars, Johannes Bühl, Henriette Gebauer, Moritz Haarig, Patric Seifert, Ulla Wandinger, and Andreas Macke
Atmos. Chem. Phys., 21, 13397–13423, https://doi.org/10.5194/acp-21-13397-2021, https://doi.org/10.5194/acp-21-13397-2021, 2021
Short summary
Short summary
A Raman lidar was operated aboard the icebreaker Polarstern during MOSAiC and monitored aerosol and cloud layers in the central Arctic up to 30 km height. The article provides an overview of the spectrum of aerosol profiling observations and shows aerosol–cloud interaction studies for liquid-water and ice clouds. A highlight was the detection of a 10 km deep wildfire smoke layer over the North Pole up to 17 km height from the fire season of 2019, which persisted over the whole winter period.
Carmen Córdoba-Jabonero, Albert Ansmann, Cristofer Jiménez, Holger Baars, María-Ángeles López-Cayuela, and Ronny Engelmann
Atmos. Meas. Tech., 14, 5225–5239, https://doi.org/10.5194/amt-14-5225-2021, https://doi.org/10.5194/amt-14-5225-2021, 2021
Short summary
Short summary
An experimental assessment of a polarized micro-pulse lidar (P-MPL) in comparison to reference lidars is presented regarding the retrieval of aerosol optical properties. The evaluation is focused on both the optimally determined overlap function and volume linear depolarization ratio. A P-MPL overlap must be regularly estimated to derive suitable aerosol products (backscatter, extinction, and particle depolarization ratio). This methodology can be easily applied to other P-MPL systems.
Hannes J. Griesche, Kevin Ohneiser, Patric Seifert, Martin Radenz, Ronny Engelmann, and Albert Ansmann
Atmos. Chem. Phys., 21, 10357–10374, https://doi.org/10.5194/acp-21-10357-2021, https://doi.org/10.5194/acp-21-10357-2021, 2021
Short summary
Short summary
Heterogeneous ice formation in Arctic mixed-phase clouds under consideration of their surface-coupling state is investigated. Cloud phase and macrophysical properties were determined by means of lidar and cloud radar measurements, the coupling state, and cloud minimum temperature by radiosonde profiles. Above −15 °C cloud minimum temperature, surface-coupled clouds are more likely to contain ice by a factor of 2–6. By means of a literature survey, causes of the observed effects are discussed.
Albert Ansmann, Kevin Ohneiser, Rodanthi-Elisavet Mamouri, Daniel A. Knopf, Igor Veselovskii, Holger Baars, Ronny Engelmann, Andreas Foth, Cristofer Jimenez, Patric Seifert, and Boris Barja
Atmos. Chem. Phys., 21, 9779–9807, https://doi.org/10.5194/acp-21-9779-2021, https://doi.org/10.5194/acp-21-9779-2021, 2021
Short summary
Short summary
We present retrievals of tropospheric and stratospheric height profiles of particle mass, volume, surface area concentration of wildfire smoke layers, and related cloud condensation nuclei (CCN) and ice-nucleating particle (INP) concentrations. The new analysis scheme is applied to ground-based lidar observations of stratospheric Australian smoke over southern South America and to spaceborne lidar observations of tropospheric North American smoke.
Carmen Córdoba-Jabonero, Michaël Sicard, María-Ángeles López-Cayuela, Albert Ansmann, Adolfo Comerón, María-Paz Zorzano, Alejandro Rodríguez-Gómez, and Constantino Muñoz-Porcar
Atmos. Chem. Phys., 21, 6455–6479, https://doi.org/10.5194/acp-21-6455-2021, https://doi.org/10.5194/acp-21-6455-2021, 2021
Short summary
Short summary
The particular pathway of dust outbreaks defines the aerosol scenario and short-wave (SW) dust direct radiative effect (DRE). The synergetic use of POLIPHON method with continuous P-MPL measurements allows SW DRE of coarse (Dc) and fine (Df) dust particles to be evaluated separately. A dust-induced cooling effect is found, and despite Dc usually being dominant in intense dust events, the Df contribution to the total DRE can be significant, being higher at the top of atmosphere than on surface.
Athena Augusta Floutsi, Konstantinos Rizos, Dimitri Trapon, Ronny Engelmann, Dietrich Althausen, Eleni Marinou, Peristera Paschou, Julian Hofer, Emmanouil Proestakis, Henriette Gebauer, Annett Skupin, Albert Ansmann, Thorsten Fehr, Timon Hummel, Rob Koopman, Vassilis Amiridis, Ulla Wandinger, and Holger Baars
Atmos. Meas. Tech., 19, 1901–1925, https://doi.org/10.5194/amt-19-1901-2026, https://doi.org/10.5194/amt-19-1901-2026, 2026
Short summary
Short summary
We assess the representativeness of a remote ground-based station in Mindelo, Cabo Verde by utilizing continuous observations of a ground-based multiwavelength polarization Raman lidar and the LIdar climatology of Vertical Aerosol Structure (LIVAS) products. Based on a statistical analysis of the optical properties at different radii around Mindelo and case studies, we conclude that overall, the ground-based station in Mindelo can be considered conditionally representative.
Henriette Gebauer, Athena Augusta Floutsi, Julian Hofer, Moritz Haarig, Annett Skupin, Ronny Engelmann, Cristofer Jimenez, Robert Wagner, and Holger Baars
Atmos. Chem. Phys., 26, 3439–3465, https://doi.org/10.5194/acp-26-3439-2026, https://doi.org/10.5194/acp-26-3439-2026, 2026
Short summary
Short summary
The annual aerosol cycle over Mindelo, Cabo Verde, was characterized using lidar and sun photometer measurements between July 2021 and August 2023. The observations were used to define and characterize the aerosol-related seasons at this location. These are the dust season (June–September), when thick layers of Saharan dust are transported over Mindelo, and the mixing season (November–March), when this dust is mixed with smoke from the African continent. April, May, and October were defined as transition months.
Kevin Ohneiser, Markus Hartmann, Heike Wex, Patric Seifert, Anja Hardt, Anna Miller, Katharina Baudrexl, Werner Thomas, Veronika Ettrichrätz, Maximilian Maahn, Tom Gaudek, Willi Schimmel, Fabian Senf, Hannes Griesche, Martin Radenz, and Jan Henneberger
Atmos. Chem. Phys., 26, 3223–3236, https://doi.org/10.5194/acp-26-3223-2026, https://doi.org/10.5194/acp-26-3223-2026, 2026
Short summary
Short summary
This study highlights the efficiency of supercooled liquid-dominated stratus clouds to remove ice-nucleating particles (INPs). When within the planetary boundary layer (PBL), lower concentrations of INPs were measured under supercooled stratus conditions, compared to when the stratus cloud layers occurred at temperatures above freezing. Under supercooling conditions, the free-troposphere above the supercooled stratus covered PBL was found to be an additional potential source of INP.
Yijia Sun, Ann M. Fridlind, Israel Silber, Nicole Riemer, and Daniel A. Knopf
Geosci. Model Dev., 19, 1581–1617, https://doi.org/10.5194/gmd-19-1581-2026, https://doi.org/10.5194/gmd-19-1581-2026, 2026
Short summary
Short summary
The role of Arctic clouds in the regional climate remains uncertain due to insufficient understanding of the amount of liquid droplets and ice crystals present in these clouds. An aerosol-cloud model is employed to examine the role of different aerosol types and freezing parameterizations on the number of ice crystals. The choice of freezing parameterization significantly changes the number of ice crystals impacting the interpretation of the evolution and warming effect of Arctic clouds.
Kangwen Sun, Guangyao Dai, Dimitri Trapon, Holger Baars, Albert Ansmann, Ulla Wandinger, and Songhua Wu
EGUsphere, https://doi.org/10.5194/egusphere-2026-596, https://doi.org/10.5194/egusphere-2026-596, 2026
This preprint is open for discussion and under review for Atmospheric Chemistry and Physics (ACP).
Short summary
Short summary
Targeting a large-scale smoke transport from the western US to Europe in September 2020 a smoke dataset was constructed based on Aeolus observations, in synergy with multi-platform data. The selected cross-sections show the vertical structure of the smoke layers at different transport phases. Statistical analyses of the complete dataset reveal the evolution of the smoke plume throughout its transatlantic transport.
Albert Ansmann, Julian Hofer, Rodanthi-Elisavet Mamouri, Moritz Haarig, Holger Baars, and Ulla Wandinger
EGUsphere, https://doi.org/10.5194/egusphere-2026-648, https://doi.org/10.5194/egusphere-2026-648, 2026
This preprint is open for discussion and under review for Atmospheric Measurement Techniques (AMT).
Short summary
Short summary
Updated lidar and ceilometer conversion factors are presented. The conversion factors allow us to calculate microphyscial properties from measurned optical properties. One the main goals is to support 355 nm lidar observations performed in the framwork of ESA's EarthCARE mission.
Simone Pulimeno, Angelo Lupi, Vito Vitale, Claudia Frangipani, Carlos Toledano, Stelios Kazadzis, Natalia Kouremeti, Christoph Ritter, Sandra Graßl, Kerstin Stebel, Vitali Fioletov, Ihab Abboud, Sandra Blindheim, Lynn Ma, Norm O'Neill, Piotr Sobolewski, Pawan Gupta, Elena Lind, Thomas F. Eck, Antti Hyvärinen, Veijo Aaltonen, Rigel Kivi, Janae Csavina, Dmitry Kabanov, Sergey M. Sakerin, Olga R. Sidorova, Robert S. Stone, Hagen Telg, Laura Riihimaki, Raul R. Cordero, Martin Radenz, Ronny Engelmann, Michel Van Roozendal, Anatoli Chaikovsky, Philippe Goloub, Junji Hisamitsu, and Mauro Mazzola
Atmos. Chem. Phys., 26, 1809–1846, https://doi.org/10.5194/acp-26-1809-2026, https://doi.org/10.5194/acp-26-1809-2026, 2026
Short summary
Short summary
This study analyzed aerosols optical properties over the Arctic and Antarctic to measure them even during long periods of darkness. It found that pollution in the Arctic is decreasing, likely due to European emission regulations, while wildfires are becoming a more important source of particles. In Antarctica, particle levels are higher near the coast than inland, and vary by season. These results help us better understand how air pollution and climate are changing at the Earth’s poles.
Yonatan Peleg, Lior Zeida-Cohen, Imri Tzror, Johannes Bühl, Albert Ansmann, Alexandra Chudnovsky, and Zohar Yakhini
EGUsphere, https://doi.org/10.5194/egusphere-2025-5215, https://doi.org/10.5194/egusphere-2025-5215, 2026
This preprint is open for discussion and under review for Atmospheric Measurement Techniques (AMT).
Short summary
Short summary
Mapping the vertical structure of aerosols and clouds is vital for climate science. We developed an AI model that reconstructs full atmospheric profiles from standard lidar data, even above signal attenuation. It accurately classifies aerosol and cloud types, capturing key atmospheric features. This cost-effective approach extends beyond sparse Cloudnet sites, enhancing monitoring and supporting improved weather and climate models.
Hannes Jascha Griesche, Ronny Engelmann, Martin Radenz, Julian Hofer, Dietrich Althausen, Albert Ansmann, Kevin Barry, Jessie Creamean, Cristofer Jimenez, and Patric Seifert
EGUsphere, https://doi.org/10.5194/egusphere-2025-5708, https://doi.org/10.5194/egusphere-2025-5708, 2025
Short summary
Short summary
A full annual cycle of mixed-phase ice-formation temperatures in the high Arctic is presented. Ship-based remote sensing with lidar and cloud radar from the Arctic expedition MOSAiC was used to investigate the impact of surface processes on mixed-phase cloud properties. Surface mixed-layer cloud coupling was derived base on radiosonde profiles. Combined with INP filter samples, sea ice concentration and back-trajectory analysis an influence of surface processes on the cloud properties was found.
Kevin Ohneiser, Patric Seifert, Willi Schimmel, Fabian Senf, Tom Gaudek, Martin Radenz, Audrey Teisseire, Veronika Ettrichrätz, Teresa Vogl, Nina Maherndl, Nils Pfeifer, Jan Henneberger, Anna J. Miller, Nadja Omanovic, Christopher Fuchs, Huiying Zhang, Fabiola Ramelli, Robert Spirig, Anton Kötsche, Heike Kalesse-Los, Maximilian Maahn, Heather Corden, Alexis Berne, Majid Hajipour, Hannes Griesche, Julian Hofer, Ronny Engelmann, Annett Skupin, Albert Ansmann, and Holger Baars
Atmos. Chem. Phys., 25, 17363–17386, https://doi.org/10.5194/acp-25-17363-2025, https://doi.org/10.5194/acp-25-17363-2025, 2025
Short summary
Short summary
This study focuses on a seeder-feeder cloud system on 8 Jan 2024 in Eriswil, Switzerland. It is shown how the interaction of these cloud systems changes the cloud microphysical properties and the precipitation patterns. A big set of advanced remote-sensing techniques and retrieval algorithms are applied, so that a detailed view on the seeder-feeder cloud system is available. The gained knowledge can be used to improve weather models and weather forecasts.
Ioanna Tsikoudi, Eleni Marinou, Maria Tombrou, Eleni Giannakaki, Emmanouil Proestakis, Konstantinos Rizos, Ville Vakkari, Holger Baars, Annett Skupin, Ronny Engelmann, Zhenping Yin, and Vassilis Amiridis
Atmos. Chem. Phys., 25, 16491–16510, https://doi.org/10.5194/acp-25-16491-2025, https://doi.org/10.5194/acp-25-16491-2025, 2025
Short summary
Short summary
We study the characteristics of the boundary layer over three areas: the tropical Atlantic, the tropical West African continent, and near Cabo Verde using PollyXT and CALIPSO (Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations) lidar measurements, as well as ECMWF (European Centre for Medium-Range Weather Forecasts) data. The findings underline the strengths and limitations of different observational and modeling approaches, and emphasizes on the importance of considering aerosol conditions and local meteorology when interpreting boundary layer dynamics.
Yun He, Goutam Choudhury, Matthias Tesche, Albert Ansmann, Fan Yi, Detlef Müller, and Zhenping Yin
Atmos. Meas. Tech., 18, 5669–5685, https://doi.org/10.5194/amt-18-5669-2025, https://doi.org/10.5194/amt-18-5669-2025, 2025
Short summary
Short summary
We present a global dataset of POlarization LIdar PHOtometer Networking (POLIPHON) dust conversion factors at 532 nm obtained using Aerosol RObotic NETwork (AERONET) observations at 137 sites for ice-nucleating particle (INP) and 123 sites for cloud condensation nucleation (CCN) calculations. We also conduct a comparison of dust CCN concentration profiles derived using both POLIPHON and the independent Optical Modelling of the CALIPSO Aerosol Microphysics (OMCAM) retrieval.
Cristofer Jimenez, Albert Ansmann, Kevin Ohneiser, Hannes Griesche, Ronny Engelmann, Martin Radenz, Julian Hofer, Dietrich Althausen, Daniel A. Knopf, Sandro Dahlke, Johannes Bühl, Holger Baars, Patric Seifert, and Ulla Wandinger
Atmos. Chem. Phys., 25, 12955–12981, https://doi.org/10.5194/acp-25-12955-2025, https://doi.org/10.5194/acp-25-12955-2025, 2025
Short summary
Short summary
We studied the water and ice phases of Arctic mixed-phase clouds (MPCs) using dual FOV polarization lidar and Doppler radar on board Polarstern during the MOSAiC expedition. Two long-lasting Arctic MPCs and year-round statistics show persistent droplet activation and dominant immersion freezing, indicating well-filled cloud condensation nuclei and ice-nucleating particle reservoirs. These findings help explain MPC longevity and may improve cloud life cycle representation in weather and climate models.
Majid Hajipour, Patric Seifert, Hannes Griesche, Kevin Ohneiser, and Martin Radenz
Atmos. Meas. Tech., 18, 5199–5222, https://doi.org/10.5194/amt-18-5199-2025, https://doi.org/10.5194/amt-18-5199-2025, 2025
Short summary
Short summary
This study presents an approach that enables the detection of the shape and orientation of multiple types of co-located hydrometeors in mixed-phase cloud systems. This information is key for improving the understanding of these clouds, as they do contain ice and liquid water simultaneously, making them relevant for the precipitation budget and radiative balance of the Earth's atmosphere. The retrieval is based on elevation scans of polarimetric cloud radars and can therefore be flexibly applied.
Christopher Fuchs, Fabiola Ramelli, Anna J. Miller, Nadja Omanovic, Robert Spirig, Huiying Zhang, Patric Seifert, Kevin Ohneiser, Ulrike Lohmann, and Jan Henneberger
Atmos. Chem. Phys., 25, 12177–12196, https://doi.org/10.5194/acp-25-12177-2025, https://doi.org/10.5194/acp-25-12177-2025, 2025
Short summary
Short summary
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. These data fill the gap in quantitative in situ observation of ice crystal growth, helping to validate models and laboratory experiments.
Wenhan Tang, Sylwester Arabas, Jeffrey H. Curtis, Daniel A. Knopf, Matthew West, and Nicole Riemer
EGUsphere, https://doi.org/10.5194/egusphere-2025-4326, https://doi.org/10.5194/egusphere-2025-4326, 2025
Short summary
Short summary
We studied how aerosol particles help form ice in clouds. Using new theory and detailed computer simulations, we found that the way different materials are mixed within these particles has a strong impact on how much ice forms. When ice-forming material is spread across all particles, more droplets freeze than when it is only in a few. This result means that to better predict clouds and climate, models need to account for how particle materials are mixed.
Tom Gaudek, Cristofer Jimenez, Kevin Ohneiser, Christopher Fuchs, Jan Henneberger, Johannes Bühl, Andi Klamt, Albert Ansmann, Ronny Engelmann, and Patric Seifert
EGUsphere, https://doi.org/10.5194/egusphere-2025-4105, https://doi.org/10.5194/egusphere-2025-4105, 2025
Short summary
Short summary
This study introduces the maximum diameter (Dmax) of precipitation particles measured by a two-dimensional video disdrometer (2DVD) as a novel parameter. Dmax is applied in a cloud seeding study during the Cloudlab campaign and, for the first time, in a MOSAiC case to evaluate the LIRAS-ice remote-sensing retrieval of in-cloud ice crystal size and number. Both quantities agreed well with the 2DVD measurements under ideal conditions, highlighting the potential of Dmax for precipitation studies.
Audrey Teisseire, Patric Seifert, Kevin Ohneiser, Maximilian Maahn, Robert Spirig, and Jan Henneberger
EGUsphere, https://doi.org/10.5194/egusphere-2025-3923, https://doi.org/10.5194/egusphere-2025-3923, 2025
Short summary
Short summary
This study evaluates the vertical distribution of particle shape (VDPS) method for identifying particle shapes and riming/aggregation using in-situ and multi-frequency radar data from the CLOUDLAB campaign. Despite non-Rayleigh scattering effects, results show that the VDPS method using a Ka-band scanning cloud radar in slanted depolarization ratio (SLDR) mode is effective for hydrometeor classification.
Sofía Gómez Maqueo Anaya, Dietrich Althausen, Julian Hofer, Moritz Haarig, Ulla Wandinger, Bernd Heinold, Ina Tegen, Matthias Faust, Holger Baars, Albert Ansmann, Ronny Engelmann, Annett Skupin, Birgit Heese, and Kerstin Schepanski
Atmos. Chem. Phys., 25, 9737–9764, https://doi.org/10.5194/acp-25-9737-2025, https://doi.org/10.5194/acp-25-9737-2025, 2025
Short summary
Short summary
This study investigates how hematite in Sahara dust affects how dust particles interact with radiation. Using lidar data from Cabo Verde (2021–2022) and hematite content from atmospheric model simulations, the results show that a higher hematite fraction leads to a decrease in the particle backscattering coefficients in a spectrally different way. These findings can improve the representation of mineral dust in climate models, particularly regarding their radiative effect.
Gladiola Malollari, Albert Ansmann, Holger Baars, Cristofer Jimenez, Julian Hofer, Ronny Engelmann, Nathan Skupin, and Seit Shallari
Atmos. Meas. Tech., 18, 3937–3944, https://doi.org/10.5194/amt-18-3937-2025, https://doi.org/10.5194/amt-18-3937-2025, 2025
Short summary
Short summary
This study presents, for the first time, the uncertainty analysis of the Ångström exponent assumption on the full set of retrievable optical properties obtained with Raman lidar. A quantitative comparison between the pure rotational and vibrational–rotational Raman lidar approaches is presented. A minor impact of a wrong Ångström exponent on the determined aerosol optical properties is found.
Zhaolong Wu, Patric Seifert, Yun He, Holger Baars, Haoran Li, Cristofer Jimenez, Chengcai Li, and Albert Ansmann
Atmos. Meas. Tech., 18, 3611–3634, https://doi.org/10.5194/amt-18-3611-2025, https://doi.org/10.5194/amt-18-3611-2025, 2025
Short summary
Short summary
This study introduces a novel method to detect horizontally oriented ice crystals (HOICs) using two ground-based polarization lidars at different zenith angles, based on a yearlong dataset collected in Beijing. Combined with cloud radar and reanalysis data, the fine categorization results reveal HOICs occur in calm winds and moderately cold temperatures and are influenced by turbulence near cloud bases. The results enhance our understanding of cloud processes and improve atmospheric models.
Hossein Panahifar, Maria Poutli, George Kotsias, Argyro Nisantzi, Silas Michaelides, Diofantos Hadjimitsis, Patric Seifert, Albert Ansmann, and Rodanthi-Elisavet Mamouri
Int. Arch. Photogramm. Remote Sens. Spatial Inf. Sci., XLVIII-G-2025, 1153–1158, https://doi.org/10.5194/isprs-archives-XLVIII-G-2025-1153-2025, https://doi.org/10.5194/isprs-archives-XLVIII-G-2025-1153-2025, 2025
Moritz Haarig, Ronny Engelmann, Holger Baars, Benedikt Gast, Dietrich Althausen, and Albert Ansmann
Atmos. Chem. Phys., 25, 7741–7763, https://doi.org/10.5194/acp-25-7741-2025, https://doi.org/10.5194/acp-25-7741-2025, 2025
Short summary
Short summary
The lidar ratio is an important quantity in aerosol typing. Its spectral slope contains information about the source region or transport paths of the observed aerosol. The extension to 1064 nm is a recent development led by our institute. We gathered previous observations and added new ones to provide the spectral slope for the most important aerosol types such as marine and continental aerosol, dust, smoke, and sulfate. We compared it to assumptions used for spaceborne backscatter lidars.
Albert Ansmann, Cristofer Jimenez, Johanna Roschke, Johannes Bühl, Kevin Ohneiser, Ronny Engelmann, Martin Radenz, Hannes Griesche, Julian Hofer, Dietrich Althausen, Daniel A. Knopf, Sandro Dahlke, Tom Gaudek, Patric Seifert, and Ulla Wandinger
Atmos. Chem. Phys., 25, 4847–4866, https://doi.org/10.5194/acp-25-4847-2025, https://doi.org/10.5194/acp-25-4847-2025, 2025
Short summary
Short summary
In this study, we focus on the potential impact of wildfire smoke on cirrus formation. For the first time, state-of-the-art aerosol and cirrus observations with lidar and radar, presented in this paper (Part 1 of a series of two articles), are closely linked to the comprehensive modeling of gravity-wave-induced ice nucleation in cirrus evolution processes, presented in a companion paper (Part 2). We found a clear impact of wildfire smoke on cirrus evolution.
Benedikt Gast, Cristofer Jimenez, Albert Ansmann, Moritz Haarig, Ronny Engelmann, Felix Fritzsch, Athena A. Floutsi, Hannes Griesche, Kevin Ohneiser, Julian Hofer, Martin Radenz, Holger Baars, Patric Seifert, and Ulla Wandinger
Atmos. Chem. Phys., 25, 3995–4011, https://doi.org/10.5194/acp-25-3995-2025, https://doi.org/10.5194/acp-25-3995-2025, 2025
Short summary
Short summary
In this study, we discuss the enhanced detection capabilities of a fluorescence lidar in the case of optically thin aerosol layers in the upper troposphere and lower stratosphere (UTLS) region. Our results suggest that such thin aerosol layers are not so rare in the UTLS and can potentially trigger and impact cirrus cloud formation through heterogeneous ice nucleation. By altering the microphysical cloud properties, this could affect clouds' evolution and lifetime and thus their climate effect.
Silke Groß, Volker Freudenthaler, Moritz Haarig, Albert Ansmann, Carlos Toledano, David Mateos, Petra Seibert, Rodanthi-Elisavet Mamouri, Argyro Nisantzi, Josef Gasteiger, Maximilian Dollner, Anne Tipka, Manuel Schöberl, Marilena Teri, and Bernadett Weinzierl
Atmos. Chem. Phys., 25, 3191–3211, https://doi.org/10.5194/acp-25-3191-2025, https://doi.org/10.5194/acp-25-3191-2025, 2025
Short summary
Short summary
Aerosols contribute to the largest uncertainties in climate change predictions. The eastern Mediterranean is a hotspot for aerosols with natural and anthropogenic contributions. We present lidar measurements performed during A-LIFE (Absorbing aerosol layers in a changing climate: aging, lifetime and dynamics) to characterize aerosols and aerosol mixtures. We extend current lidar classification and separation schemes and compare them to classification schemes using different methods.
Johanna Roschke, Jonas Witthuhn, Marcus Klingebiel, Moritz Haarig, Andreas Foth, Anton Kötsche, and Heike Kalesse-Los
Atmos. Meas. Tech., 18, 487–508, https://doi.org/10.5194/amt-18-487-2025, https://doi.org/10.5194/amt-18-487-2025, 2025
Short summary
Short summary
We present a technique to discriminate between the Cloudnet target classification of "drizzle or rain" and sea salt aerosols that is applicable to marine Cloudnet sites. The method is crucial for investigating the occurrence of precipitation and significantly improves the Cloudnet target classification scheme for measurements over the Barbados Cloud Observatory (BCO). A first-ever analysis of the Cloudnet product including the new "haze echo" target over 2 years at the BCO is presented.
Yun He, Dongzhe Jing, Zhenping Yin, Kevin Ohneiser, and Fan Yi
Atmos. Chem. Phys., 24, 11431–11450, https://doi.org/10.5194/acp-24-11431-2024, https://doi.org/10.5194/acp-24-11431-2024, 2024
Short summary
Short summary
We present a long-term ground-based lidar observation of stratospheric aerosols at a mid-latitude site, Wuhan, in central China, from 2010 to 2021. We observed a stratospheric background period from 2013 to mid-2017, along with several perturbations from volcanic aerosols and wildfire-induced smoke. In summer, injected stratospheric aerosols are found to be captured by the Asian monsoon anticyclone, resulting in prolonged residence and regional transport in the mid-latitudes of East Asia.
Nadja Omanovic, Sylvaine Ferrachat, Christopher Fuchs, Jan Henneberger, Anna J. Miller, Kevin Ohneiser, Fabiola Ramelli, Patric Seifert, Robert Spirig, Huiying Zhang, and Ulrike Lohmann
Atmos. Chem. Phys., 24, 6825–6844, https://doi.org/10.5194/acp-24-6825-2024, https://doi.org/10.5194/acp-24-6825-2024, 2024
Short summary
Short summary
We present simulations with a high-resolution numerical weather prediction model to study the growth of ice crystals in low clouds following glaciogenic seeding. We show that the simulated ice crystals grow slower than observed and do not consume as many cloud droplets as measured in the field. This may have implications for forecasting precipitation, as the ice phase is crucial for precipitation at middle and high latitudes.
Henriette Gebauer, Athena Augusta Floutsi, Moritz Haarig, Martin Radenz, Ronny Engelmann, Dietrich Althausen, Annett Skupin, Albert Ansmann, Cordula Zenk, and Holger Baars
Atmos. Chem. Phys., 24, 5047–5067, https://doi.org/10.5194/acp-24-5047-2024, https://doi.org/10.5194/acp-24-5047-2024, 2024
Short summary
Short summary
Sulfate aerosol from the volcanic eruption at La Palma in 2021 was observed over Cabo Verde. We characterized the aerosol burden based on a case study of lidar and sun photometer observations. We compared the volcanic case to the typical background conditions (reference case) to quantify the volcanic pollution. We show the first ever measurements of the extinction coefficient, lidar ratio and depolarization ratio at 1064 nm for volcanic sulfate.
Daniel A. Knopf, Markus Ammann, Thomas Berkemeier, Ulrich Pöschl, and Manabu Shiraiwa
Atmos. Chem. Phys., 24, 3445–3528, https://doi.org/10.5194/acp-24-3445-2024, https://doi.org/10.5194/acp-24-3445-2024, 2024
Short summary
Short summary
The initial step of interfacial and multiphase chemical processes involves adsorption and desorption of gas species. This study demonstrates the role of desorption energy governing the residence time of the gas species at the environmental interface. A parameterization is formulated that enables the prediction of desorption energy based on the molecular weight, polarizability, and oxygen-to-carbon ratio of the desorbing chemical species. Its application to gas–particle interactions is discussed.
Sofía Gómez Maqueo Anaya, Dietrich Althausen, Matthias Faust, Holger Baars, Bernd Heinold, Julian Hofer, Ina Tegen, Albert Ansmann, Ronny Engelmann, Annett Skupin, Birgit Heese, and Kerstin Schepanski
Geosci. Model Dev., 17, 1271–1295, https://doi.org/10.5194/gmd-17-1271-2024, https://doi.org/10.5194/gmd-17-1271-2024, 2024
Short summary
Short summary
Mineral dust aerosol particles vary greatly in their composition depending on source region, which leads to different physicochemical properties. Most atmosphere–aerosol models consider mineral dust aerosols to be compositionally homogeneous, which ultimately increases model uncertainty. Here, we present an approach to explicitly consider the heterogeneity of the mineralogical composition for simulations of the Saharan atmospheric dust cycle with regard to dust transport towards the Atlantic.
Audrey Teisseire, Patric Seifert, Alexander Myagkov, Johannes Bühl, and Martin Radenz
Atmos. Meas. Tech., 17, 999–1016, https://doi.org/10.5194/amt-17-999-2024, https://doi.org/10.5194/amt-17-999-2024, 2024
Short summary
Short summary
The vertical distribution of particle shape (VDPS) method, introduced in this study, aids in characterizing the density-weighted shape of cloud particles from scanning slanted linear depolarization ratio (SLDR)-mode cloud radar observations. The VDPS approach represents a new, versatile way to study microphysical processes by combining a spheroidal scattering model with real measurements of SLDR.
Julian Hofer, Patric Seifert, J. Ben Liley, Martin Radenz, Osamu Uchino, Isamu Morino, Tetsu Sakai, Tomohiro Nagai, and Albert Ansmann
Atmos. Chem. Phys., 24, 1265–1280, https://doi.org/10.5194/acp-24-1265-2024, https://doi.org/10.5194/acp-24-1265-2024, 2024
Short summary
Short summary
An 11-year dataset of polarization lidar observations from Lauder, New Zealand / Aotearoa, was used to distinguish the thermodynamic phase of natural clouds. The cloud dataset was separated to assess the impact of air mass origin on the frequency of heterogeneous ice formation. Ice formation efficiency in clouds above Lauder was found to be lower than in the polluted Northern Hemisphere midlatitudes but higher than in very clean and pristine environments, such as Punta Arenas in southern Chile.
Rodanthi-Elisavet Mamouri, Albert Ansmann, Kevin Ohneiser, Daniel A. Knopf, Argyro Nisantzi, Johannes Bühl, Ronny Engelmann, Annett Skupin, Patric Seifert, Holger Baars, Dragos Ene, Ulla Wandinger, and Diofantos Hadjimitsis
Atmos. Chem. Phys., 23, 14097–14114, https://doi.org/10.5194/acp-23-14097-2023, https://doi.org/10.5194/acp-23-14097-2023, 2023
Short summary
Short summary
For the first time, rather clear evidence is found that wildfire smoke particles can trigger strong cirrus formation. This finding is of importance because intensive and large wildfires may occur increasingly often in the future as climate change proceeds. Based on lidar observations in Cyprus in autumn 2020, we provide detailed insight into the cirrus formation at the tropopause in the presence of aged wildfire smoke (here, 8–9 day old Californian wildfire smoke).
Albert Ansmann, Kevin Ohneiser, Ronny Engelmann, Martin Radenz, Hannes Griesche, Julian Hofer, Dietrich Althausen, Jessie M. Creamean, Matthew C. Boyer, Daniel A. Knopf, Sandro Dahlke, Marion Maturilli, Henriette Gebauer, Johannes Bühl, Cristofer Jimenez, Patric Seifert, and Ulla Wandinger
Atmos. Chem. Phys., 23, 12821–12849, https://doi.org/10.5194/acp-23-12821-2023, https://doi.org/10.5194/acp-23-12821-2023, 2023
Short summary
Short summary
The 1-year MOSAiC (2019–2020) expedition with the German ice breaker Polarstern was the largest polar field campaign ever conducted. The Polarstern, with our lidar aboard, drifted with the pack ice north of 85° N for more than 7 months (October 2019 to mid-May 2020). We measured the full annual cycle of aerosol conditions in terms of aerosol optical and cloud-process-relevant properties. We observed a strong contrast between polluted winter and clean summer aerosol conditions.
Holger Baars, Joshua Walchester, Elizaveta Basharova, Henriette Gebauer, Martin Radenz, Johannes Bühl, Boris Barja, Ulla Wandinger, and Patric Seifert
Atmos. Meas. Tech., 16, 3809–3834, https://doi.org/10.5194/amt-16-3809-2023, https://doi.org/10.5194/amt-16-3809-2023, 2023
Short summary
Short summary
In 2018, the Aeolus satellite of the European Space Agency (ESA) was launched to improve weather forecasts through global measurements of wind profiles. Given the novel lidar technique onboard, extensive validation efforts have been needed to verify the observations. For this reason, we performed long-term validation measurements in Germany and Chile. We found significant improvement in the data products due to a new algorithm version and can confirm the general validity of Aeolus observations.
Daniel A. Knopf, Peiwen Wang, Benny Wong, Jay M. Tomlin, Daniel P. Veghte, Nurun N. Lata, Swarup China, Alexander Laskin, Ryan C. Moffet, Josephine Y. Aller, Matthew A. Marcus, and Jian Wang
Atmos. Chem. Phys., 23, 8659–8681, https://doi.org/10.5194/acp-23-8659-2023, https://doi.org/10.5194/acp-23-8659-2023, 2023
Short summary
Short summary
Ambient particle populations and associated ice-nucleating particles (INPs)
were examined from particle samples collected on board aircraft in the marine
boundary layer and free troposphere in the eastern North Atlantic during
summer and winter. Chemical imaging shows distinct differences in the
particle populations seasonally and with sampling altitudes, which are
reflected in the INP types. Freezing parameterizations are derived for
implementation in cloud-resolving and climate models.
Ulla Wandinger, Athena Augusta Floutsi, Holger Baars, Moritz Haarig, Albert Ansmann, Anja Hünerbein, Nicole Docter, David Donovan, Gerd-Jan van Zadelhoff, Shannon Mason, and Jason Cole
Atmos. Meas. Tech., 16, 2485–2510, https://doi.org/10.5194/amt-16-2485-2023, https://doi.org/10.5194/amt-16-2485-2023, 2023
Short summary
Short summary
We introduce an aerosol classification model that has been developed for the Earth Clouds, Aerosols and Radiation Explorer (EarthCARE). The model provides a consistent description of microphysical, optical, and radiative properties of common aerosol types such as dust, sea salt, pollution, and smoke. It is used for aerosol classification and assessment of radiation effects based on the synergy of active and passive observations with lidar, imager, and radiometer of the multi-instrument platform.
Athena Augusta Floutsi, Holger Baars, Ronny Engelmann, Dietrich Althausen, Albert Ansmann, Stephanie Bohlmann, Birgit Heese, Julian Hofer, Thomas Kanitz, Moritz Haarig, Kevin Ohneiser, Martin Radenz, Patric Seifert, Annett Skupin, Zhenping Yin, Sabur F. Abdullaev, Mika Komppula, Maria Filioglou, Elina Giannakaki, Iwona S. Stachlewska, Lucja Janicka, Daniele Bortoli, Eleni Marinou, Vassilis Amiridis, Anna Gialitaki, Rodanthi-Elisavet Mamouri, Boris Barja, and Ulla Wandinger
Atmos. Meas. Tech., 16, 2353–2379, https://doi.org/10.5194/amt-16-2353-2023, https://doi.org/10.5194/amt-16-2353-2023, 2023
Short summary
Short summary
DeLiAn is a collection of lidar-derived aerosol intensive optical properties for several aerosol types, namely the particle linear depolarization ratio, the extinction-to-backscatter ratio (lidar ratio) and the Ångström exponent. The data collection is based on globally distributed, long-term, ground-based, multiwavelength, Raman and polarization lidar measurements and currently covers two wavelengths, 355 and 532 nm, for 13 aerosol categories ranging from basic aerosol types to mixtures.
Yun He, Zhenping Yin, Albert Ansmann, Fuchao Liu, Longlong Wang, Dongzhe Jing, and Huijia Shen
Atmos. Meas. Tech., 16, 1951–1970, https://doi.org/10.5194/amt-16-1951-2023, https://doi.org/10.5194/amt-16-1951-2023, 2023
Short summary
Short summary
With the AERONET database, this study derives dust-related conversion factors at oceanic sites used in the POLIPHON method, which can convert lidar-retrieved dust extinction to ice-nucleating particle (INP)- and cloud condensation nuclei (CCN)-relevant parameters. The particle linear depolarization ratio in the AERONET aerosol inversion product is used to identify dust data points. The derived conversion factors can be applied to inverse 3-D global distributions of dust-related INPCs and CCNCs.
Kevin Ohneiser, Albert Ansmann, Jonas Witthuhn, Hartwig Deneke, Alexandra Chudnovsky, Gregor Walter, and Fabian Senf
Atmos. Chem. Phys., 23, 2901–2925, https://doi.org/10.5194/acp-23-2901-2023, https://doi.org/10.5194/acp-23-2901-2023, 2023
Short summary
Short summary
This study shows that smoke layers can reach the tropopause via the self-lofting effect within 3–7 d in the absence of pyrocumulonimbus convection if the
aerosol optical thickness is larger than approximately 2 for a longer time period. When reaching the stratosphere, wildfire smoke can sensitively influence the stratospheric composition on a hemispheric scale and thus can affect the Earth’s climate and the ozone layer.
Albert Ansmann, Kevin Ohneiser, Alexandra Chudnovsky, Daniel A. Knopf, Edwin W. Eloranta, Diego Villanueva, Patric Seifert, Martin Radenz, Boris Barja, Félix Zamorano, Cristofer Jimenez, Ronny Engelmann, Holger Baars, Hannes Griesche, Julian Hofer, Dietrich Althausen, and Ulla Wandinger
Atmos. Chem. Phys., 22, 11701–11726, https://doi.org/10.5194/acp-22-11701-2022, https://doi.org/10.5194/acp-22-11701-2022, 2022
Short summary
Short summary
For the first time we present a systematic study on the impact of wildfire smoke on ozone depletion in the Arctic (2020) and Antarctic stratosphere (2020, 2021). Two major fire events in Siberia and Australia were responsible for the observed record-breaking stratospheric smoke pollution. Our analyses were based on lidar observations of smoke parameters (Polarstern, Punta Arenas) and NDACC Arctic and Antarctic ozone profiles as well as on Antarctic OMI satellite observations of column ozone.
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
Short summary
Short summary
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.
Bernd Heinold, Holger Baars, Boris Barja, Matthew Christensen, Anne Kubin, Kevin Ohneiser, Kerstin Schepanski, Nick Schutgens, Fabian Senf, Roland Schrödner, Diego Villanueva, and Ina Tegen
Atmos. Chem. Phys., 22, 9969–9985, https://doi.org/10.5194/acp-22-9969-2022, https://doi.org/10.5194/acp-22-9969-2022, 2022
Short summary
Short summary
The extreme 2019–2020 Australian wildfires produced massive smoke plumes lofted into the lower stratosphere by pyrocumulonimbus convection. Most climate models do not adequately simulate the injection height of such intense fires. By combining aerosol-climate modeling with prescribed pyroconvective smoke injection and lidar observations, this study shows the importance of the representation of the most extreme wildfire events for estimating the atmospheric energy budget.
Jörg Wieder, Nikola Ihn, Claudia Mignani, Moritz Haarig, Johannes Bühl, Patric Seifert, Ronny Engelmann, Fabiola Ramelli, Zamin A. Kanji, Ulrike Lohmann, and Jan Henneberger
Atmos. Chem. Phys., 22, 9767–9797, https://doi.org/10.5194/acp-22-9767-2022, https://doi.org/10.5194/acp-22-9767-2022, 2022
Short summary
Short summary
Ice formation and its evolution in mixed-phase clouds are still uncertain. We evaluate the lidar retrieval of ice-nucleating particle concentration in dust-dominated and continental air masses over the Swiss Alps with in situ observations. A calibration factor to improve the retrieval from continental air masses is proposed. Ice multiplication factors are obtained with a new method utilizing remote sensing. Our results indicate that secondary ice production occurs at temperatures down to −30 °C.
Kevin Ohneiser, Albert Ansmann, Bernd Kaifler, Alexandra Chudnovsky, Boris Barja, Daniel A. Knopf, Natalie Kaifler, Holger Baars, Patric Seifert, Diego Villanueva, Cristofer Jimenez, Martin Radenz, Ronny Engelmann, Igor Veselovskii, and Félix Zamorano
Atmos. Chem. Phys., 22, 7417–7442, https://doi.org/10.5194/acp-22-7417-2022, https://doi.org/10.5194/acp-22-7417-2022, 2022
Short summary
Short summary
We present and discuss 2 years of long-term lidar observations of the largest stratospheric perturbation by wildfire smoke ever observed. The smoke originated from the record-breaking Australian fires in 2019–2020 and affects climate conditions and even the ozone layer in the Southern Hemisphere. The obvious link between dense smoke occurrence in the stratosphere and strong ozone depletion found in the Arctic and in the Antarctic in 2020 can be regarded as a new aspect of climate change.
Goutam Choudhury, Albert Ansmann, and Matthias Tesche
Atmos. Chem. Phys., 22, 7143–7161, https://doi.org/10.5194/acp-22-7143-2022, https://doi.org/10.5194/acp-22-7143-2022, 2022
Short summary
Short summary
Lidars provide height-resolved type-specific aerosol properties and are key in studying vertically collocated aerosols and clouds. In this study, we compare the aerosol number concentrations derived from spaceborne lidar with the in situ flight measurements. Our results show a reasonable agreement between both datasets. Such an agreement has not been achieved yet. It shows the potential of spaceborne lidar in studying aerosol–cloud interactions, which is needed to improve our climate forecasts.
Daniel A. Knopf, Joseph C. Charnawskas, Peiwen Wang, Benny Wong, Jay M. Tomlin, Kevin A. Jankowski, Matthew Fraund, Daniel P. Veghte, Swarup China, Alexander Laskin, Ryan C. Moffet, Mary K. Gilles, Josephine Y. Aller, Matthew A. Marcus, Shira Raveh-Rubin, and Jian Wang
Atmos. Chem. Phys., 22, 5377–5398, https://doi.org/10.5194/acp-22-5377-2022, https://doi.org/10.5194/acp-22-5377-2022, 2022
Short summary
Short summary
Marine boundary layer aerosols collected in the remote region of the eastern North Atlantic induce immersion freezing and deposition ice nucleation under typical mixed-phase and cirrus cloud conditions. Corresponding ice nucleation parameterizations for model applications have been derived. Chemical imaging of ambient aerosol and ice-nucleating particles demonstrates that the latter is dominated by sea salt and organics while also representing a major particle type in the particle population.
Igor Veselovskii, Qiaoyun Hu, Albert Ansmann, Philippe Goloub, Thierry Podvin, and Mikhail Korenskiy
Atmos. Chem. Phys., 22, 5209–5221, https://doi.org/10.5194/acp-22-5209-2022, https://doi.org/10.5194/acp-22-5209-2022, 2022
Short summary
Short summary
A remote sensing method based on fluorescence lidar measurements can detect and quantify the smoke content in the upper troposphere and inside cirrus clouds. Based on two case studies, we demonstrate that the fluorescence lidar technique provides the possibility to estimate the smoke surface area concentration within freshly formed cirrus layers. This value was used in a smoke ice nucleating particle parameterization scheme to predict ice crystal number concentrations in cirrus generation cells.
Michaël Sicard, Carmen Córdoba-Jabonero, María-Ángeles López-Cayuela, Albert Ansmann, Adolfo Comerón, María-Paz Zorzano, Alejandro Rodríguez-Gómez, and Constantino Muñoz-Porcar
Atmos. Chem. Phys., 22, 1921–1937, https://doi.org/10.5194/acp-22-1921-2022, https://doi.org/10.5194/acp-22-1921-2022, 2022
Short summary
Short summary
This paper completes the companion paper of Córdoba-Jabonero et al. (2021). We estimate the total direct radiative effect produced by mineral dust particles during the June 2019 mega-heatwave at two sites in Spain and Germany. The results show that the dust particles in the atmosphere contribute to cooling the surface (less radiation reaches the surface) and that the heatwave (parametrized by high surface and air temperatures) contributes to reducing this cooling.
Jerónimo Escribano, Enza Di Tomaso, Oriol Jorba, Martina Klose, Maria Gonçalves Ageitos, Francesca Macchia, Vassilis Amiridis, Holger Baars, Eleni Marinou, Emmanouil Proestakis, Claudia Urbanneck, Dietrich Althausen, Johannes Bühl, Rodanthi-Elisavet Mamouri, and Carlos Pérez García-Pando
Atmos. Chem. Phys., 22, 535–560, https://doi.org/10.5194/acp-22-535-2022, https://doi.org/10.5194/acp-22-535-2022, 2022
Short summary
Short summary
We explore the benefits and consistency in adding lidar dust observations in a dust optical depth assimilation. We show that adding lidar data to a dust optical depth assimilation has valuable benefits and the dust analysis improves. We discuss the impact of the narrow satellite footprint of the lidar dust observations on the assimilation.
Moritz Haarig, Albert Ansmann, Ronny Engelmann, Holger Baars, Carlos Toledano, Benjamin Torres, Dietrich Althausen, Martin Radenz, and Ulla Wandinger
Atmos. Chem. Phys., 22, 355–369, https://doi.org/10.5194/acp-22-355-2022, https://doi.org/10.5194/acp-22-355-2022, 2022
Short summary
Short summary
The irregular shape of dust particles makes it difficult to treat them correctly in optical models. Atmospheric measurements of dust optical properties are therefore of great importance. The present study increases the space of observed parameters from 355 and 532 nm towards 1064 nm, which is of special importance for large dust particles. The lidar ratio influenced by mineralogy and the depolarization ratio influenced by shape are measured for the first time at all three wavelengths.
Jay M. Tomlin, Kevin A. Jankowski, Daniel P. Veghte, Swarup China, Peiwen Wang, Matthew Fraund, Johannes Weis, Guangjie Zheng, Yang Wang, Felipe Rivera-Adorno, Shira Raveh-Rubin, Daniel A. Knopf, Jian Wang, Mary K. Gilles, Ryan C. Moffet, and Alexander Laskin
Atmos. Chem. Phys., 21, 18123–18146, https://doi.org/10.5194/acp-21-18123-2021, https://doi.org/10.5194/acp-21-18123-2021, 2021
Short summary
Short summary
Analysis of individual atmospheric particles shows that aerosol transported from North America during meteorological dry intrusion episodes may have a substantial impact on the mixing state and particle-type population over the mid-Atlantic, as organic contribution and particle-type diversity are significantly enhanced during these periods. These observations need to be considered in current atmospheric models.
Martin Radenz, Johannes Bühl, Patric Seifert, Holger Baars, Ronny Engelmann, Boris Barja González, Rodanthi-Elisabeth Mamouri, Félix Zamorano, and Albert Ansmann
Atmos. Chem. Phys., 21, 17969–17994, https://doi.org/10.5194/acp-21-17969-2021, https://doi.org/10.5194/acp-21-17969-2021, 2021
Short summary
Short summary
This study brings together long-term ground-based remote-sensing observations of mixed-phase clouds at three key locations of aerosol–cloud interactions in the Northern and Southern Hemisphere midlatitudes. The findings contribute several new aspects on the nature of the excess of supercooled liquid clouds in the Southern Hemisphere, such as a long-term lidar-based estimate of ice-nucleating particle profiles as well as the effects of boundary layer coupling and gravity waves on ice formation.
Sebastian Düsing, Albert Ansmann, Holger Baars, Joel C. Corbin, Cyrielle Denjean, Martin Gysel-Beer, Thomas Müller, Laurent Poulain, Holger Siebert, Gerald Spindler, Thomas Tuch, Birgit Wehner, and Alfred Wiedensohler
Atmos. Chem. Phys., 21, 16745–16773, https://doi.org/10.5194/acp-21-16745-2021, https://doi.org/10.5194/acp-21-16745-2021, 2021
Short summary
Short summary
The work deals with optical properties of aerosol particles in dried and atmospheric states. Based on two measurement campaigns in the rural background of central Europe, different measurement approaches were compared with each other, such as modeling based on Mie theory and direct in situ or remote sensing measurements. Among others, it was shown that the aerosol extinction-to-backscatter ratio is relative humidity dependent, and refinement with respect to the model input parameters is needed.
Kevin Ohneiser, Albert Ansmann, Alexandra Chudnovsky, Ronny Engelmann, Christoph Ritter, Igor Veselovskii, Holger Baars, Henriette Gebauer, Hannes Griesche, Martin Radenz, Julian Hofer, Dietrich Althausen, Sandro Dahlke, and Marion Maturilli
Atmos. Chem. Phys., 21, 15783–15808, https://doi.org/10.5194/acp-21-15783-2021, https://doi.org/10.5194/acp-21-15783-2021, 2021
Short summary
Short summary
The highlight of the lidar measurements during the 1-year MOSAiC (Multidisciplinary drifting Observatory for the Study of Arctic Climate) expedition of the German icebreaker Polarstern (October 2019–October 2020) was the detection of a persistent, 10 km deep Siberian wildfire smoke layer in the upper troposphere and lower stratosphere (UTLS) from about 7–8 km to 17–18 km height that could potentially have impacted the record-breaking ozone depletion over the Arctic in the spring of 2020.
Daniel A. Knopf and Markus Ammann
Atmos. Chem. Phys., 21, 15725–15753, https://doi.org/10.5194/acp-21-15725-2021, https://doi.org/10.5194/acp-21-15725-2021, 2021
Short summary
Short summary
Adsorption on and desorption of gas molecules from solid or liquid surfaces or interfaces represent the initial interaction of gas-to-condensed-phase processes that can define the physicochemical evolution of the condensed phase. We apply a thermodynamic and microscopic treatment of these multiphase processes to evaluate how adsorption and desorption rates and surface accommodation depend on the choice of adsorption model and standard states with implications for desorption energy and lifetimes.
Ronny Engelmann, Albert Ansmann, Kevin Ohneiser, Hannes Griesche, Martin Radenz, Julian Hofer, Dietrich Althausen, Sandro Dahlke, Marion Maturilli, Igor Veselovskii, Cristofer Jimenez, Robert Wiesen, Holger Baars, Johannes Bühl, Henriette Gebauer, Moritz Haarig, Patric Seifert, Ulla Wandinger, and Andreas Macke
Atmos. Chem. Phys., 21, 13397–13423, https://doi.org/10.5194/acp-21-13397-2021, https://doi.org/10.5194/acp-21-13397-2021, 2021
Short summary
Short summary
A Raman lidar was operated aboard the icebreaker Polarstern during MOSAiC and monitored aerosol and cloud layers in the central Arctic up to 30 km height. The article provides an overview of the spectrum of aerosol profiling observations and shows aerosol–cloud interaction studies for liquid-water and ice clouds. A highlight was the detection of a 10 km deep wildfire smoke layer over the North Pole up to 17 km height from the fire season of 2019, which persisted over the whole winter period.
Carmen Córdoba-Jabonero, Albert Ansmann, Cristofer Jiménez, Holger Baars, María-Ángeles López-Cayuela, and Ronny Engelmann
Atmos. Meas. Tech., 14, 5225–5239, https://doi.org/10.5194/amt-14-5225-2021, https://doi.org/10.5194/amt-14-5225-2021, 2021
Short summary
Short summary
An experimental assessment of a polarized micro-pulse lidar (P-MPL) in comparison to reference lidars is presented regarding the retrieval of aerosol optical properties. The evaluation is focused on both the optimally determined overlap function and volume linear depolarization ratio. A P-MPL overlap must be regularly estimated to derive suitable aerosol products (backscatter, extinction, and particle depolarization ratio). This methodology can be easily applied to other P-MPL systems.
Yang Wang, Guangjie Zheng, Michael P. Jensen, Daniel A. Knopf, Alexander Laskin, Alyssa A. Matthews, David Mechem, Fan Mei, Ryan Moffet, Arthur J. Sedlacek, John E. Shilling, Stephen Springston, Amy Sullivan, Jason Tomlinson, Daniel Veghte, Rodney Weber, Robert Wood, Maria A. Zawadowicz, and Jian Wang
Atmos. Chem. Phys., 21, 11079–11098, https://doi.org/10.5194/acp-21-11079-2021, https://doi.org/10.5194/acp-21-11079-2021, 2021
Short summary
Short summary
This paper reports the vertical profiles of trace gas and aerosol properties over the eastern North Atlantic, a region of persistent but diverse subtropical marine boundary layer (MBL) clouds. We examined the key processes that drive the cloud condensation nuclei (CCN) population and how it varies with season and synoptic conditions. This study helps improve the model representation of the aerosol processes in the remote MBL, reducing the simulated aerosol indirect effects.
Hannes J. Griesche, Kevin Ohneiser, Patric Seifert, Martin Radenz, Ronny Engelmann, and Albert Ansmann
Atmos. Chem. Phys., 21, 10357–10374, https://doi.org/10.5194/acp-21-10357-2021, https://doi.org/10.5194/acp-21-10357-2021, 2021
Short summary
Short summary
Heterogeneous ice formation in Arctic mixed-phase clouds under consideration of their surface-coupling state is investigated. Cloud phase and macrophysical properties were determined by means of lidar and cloud radar measurements, the coupling state, and cloud minimum temperature by radiosonde profiles. Above −15 °C cloud minimum temperature, surface-coupled clouds are more likely to contain ice by a factor of 2–6. By means of a literature survey, causes of the observed effects are discussed.
Albert Ansmann, Kevin Ohneiser, Rodanthi-Elisavet Mamouri, Daniel A. Knopf, Igor Veselovskii, Holger Baars, Ronny Engelmann, Andreas Foth, Cristofer Jimenez, Patric Seifert, and Boris Barja
Atmos. Chem. Phys., 21, 9779–9807, https://doi.org/10.5194/acp-21-9779-2021, https://doi.org/10.5194/acp-21-9779-2021, 2021
Short summary
Short summary
We present retrievals of tropospheric and stratospheric height profiles of particle mass, volume, surface area concentration of wildfire smoke layers, and related cloud condensation nuclei (CCN) and ice-nucleating particle (INP) concentrations. The new analysis scheme is applied to ground-based lidar observations of stratospheric Australian smoke over southern South America and to spaceborne lidar observations of tropospheric North American smoke.
Fabiola Ramelli, Jan Henneberger, Robert O. David, Johannes Bühl, Martin Radenz, Patric Seifert, Jörg Wieder, Annika Lauber, Julie T. Pasquier, Ronny Engelmann, Claudia Mignani, Maxime Hervo, and Ulrike Lohmann
Atmos. Chem. Phys., 21, 6681–6706, https://doi.org/10.5194/acp-21-6681-2021, https://doi.org/10.5194/acp-21-6681-2021, 2021
Short summary
Short summary
Orographic mixed-phase clouds are an important source of precipitation, but the ice formation processes within them remain uncertain. Here we investigate the origin of ice crystals in a mixed-phase cloud in the Swiss Alps using aerosol and cloud data from in situ and remote sensing observations. We found that ice formation primarily occurs in cloud top generating cells. Our results indicate that secondary ice processes are active in the feeder region, which can enhance orographic precipitation.
Carmen Córdoba-Jabonero, Michaël Sicard, María-Ángeles López-Cayuela, Albert Ansmann, Adolfo Comerón, María-Paz Zorzano, Alejandro Rodríguez-Gómez, and Constantino Muñoz-Porcar
Atmos. Chem. Phys., 21, 6455–6479, https://doi.org/10.5194/acp-21-6455-2021, https://doi.org/10.5194/acp-21-6455-2021, 2021
Short summary
Short summary
The particular pathway of dust outbreaks defines the aerosol scenario and short-wave (SW) dust direct radiative effect (DRE). The synergetic use of POLIPHON method with continuous P-MPL measurements allows SW DRE of coarse (Dc) and fine (Df) dust particles to be evaluated separately. A dust-induced cooling effect is found, and despite Dc usually being dominant in intense dust events, the Df contribution to the total DRE can be significant, being higher at the top of atmosphere than on surface.
Ville Vakkari, Holger Baars, Stephanie Bohlmann, Johannes Bühl, Mika Komppula, Rodanthi-Elisavet Mamouri, and Ewan James O'Connor
Atmos. Chem. Phys., 21, 5807–5820, https://doi.org/10.5194/acp-21-5807-2021, https://doi.org/10.5194/acp-21-5807-2021, 2021
Short summary
Short summary
The depolarization ratio is a valuable parameter for aerosol categorization from remote sensing measurements. Here, we introduce particle depolarization ratio measurements at the 1565 nm wavelength, which is substantially longer than previously utilized wavelengths and enhances our capabilities to study the wavelength dependency of the particle depolarization ratio.
Fabiola Ramelli, Jan Henneberger, Robert O. David, Annika Lauber, Julie T. Pasquier, Jörg Wieder, Johannes Bühl, Patric Seifert, Ronny Engelmann, Maxime Hervo, and Ulrike Lohmann
Atmos. Chem. Phys., 21, 5151–5172, https://doi.org/10.5194/acp-21-5151-2021, https://doi.org/10.5194/acp-21-5151-2021, 2021
Short summary
Short summary
Interactions between dynamics, microphysics and orography can enhance precipitation. Yet the exact role of these interactions is still uncertain. Here we investigate the role of low-level blocking and turbulence for precipitation by combining remote sensing and in situ observations. The observations show that blocked flow can induce the formation of feeder clouds and that turbulence can enhance hydrometeor growth, demonstrating the importance of local flow effects for orographic precipitation.
Alexander Zaytsev, Martin Breitenlechner, Anna Novelli, Hendrik Fuchs, Daniel A. Knopf, Jesse H. Kroll, and Frank N. Keutsch
Atmos. Meas. Tech., 14, 2501–2513, https://doi.org/10.5194/amt-14-2501-2021, https://doi.org/10.5194/amt-14-2501-2021, 2021
Short summary
Short summary
We have developed an online method for speciated measurements of organic peroxy radicals and stabilized Criegee intermediates using chemical derivatization combined with chemical ionization mass spectrometry. Chemical derivatization prevents secondary radical reactions and eliminates potential interferences. Comparison between our measurements and results from numeric modeling shows that the method can be used for the quantification of a wide range of atmospheric radicals and intermediates.
Cited articles
Ansmann, A., Wandinger, U., Wiedensohler, A., and Leiterer, U.: Lindenberg Aerosol Characterization Experiment 1998 (LACE 98): Overview, J. Geophys. Res.-Atmos., 107, LAC 11-1–LAC 11-12, https://doi.org/10.1029/2000JD000233, 2002. a
Ansmann, A., Ohneiser, K., Mamouri, R.-E., Knopf, D. A., Veselovskii, I., Baars, H., Engelmann, R., Foth, A., Jimenez, C., Seifert, P., and Barja, B.: Tropospheric and stratospheric wildfire smoke profiling with lidar: mass, surface area, CCN, and INP retrieval, Atmos. Chem. Phys., 21, 9779–9807, https://doi.org/10.5194/acp-21-9779-2021, 2021. a, b, c, d, e, f
Ansmann, A., Ohneiser, K., Engelmann, R., Radenz, M., Griesche, H., Hofer, J., Althausen, D., Creamean, J. M., Boyer, M. C., Knopf, D. A., Dahlke, S., Maturilli, M., Gebauer, H., Bühl, J., Jimenez, C., Seifert, P., and Wandinger, U.: Annual cycle of aerosol properties over the central Arctic during MOSAiC 2019–2020 – light-extinction, CCN, and INP levels from the boundary layer to the tropopause, Atmos. Chem. Phys., 23, 12821–12849, https://doi.org/10.5194/acp-23-12821-2023, 2023. a, b, c, d
Ansmann, A., Veselovskii, I., Ohneiser, K., and Chudnovsky, A.: Comment on “Stratospheric Aerosol Composition Observed by the Atmospheric Chemistry Experiment Following the 2019 Raikoke Eruption” by Boone et al., J. Geophys. Res.-Atmos., 129, e2022JD038080, https://doi.org/10.1029/2022JD038080, 2024. a, b
Ansmann, A., Jimenez, C., Roschke, J., Bühl, J., Ohneiser, K., Engelmann, R., Radenz, M., Griesche, H., Hofer, J., Althausen, D., Knopf, D. A., Dahlke, S., Gaudek, T., Seifert, P., and Wandinger, U.: Impact of wildfire smoke on Arctic cirrus formation – Part 1: Analysis of MOSAiC 2019–2020 observations, Atmos. Chem. Phys., 25, 4847–4866, https://doi.org/10.5194/acp-25-4847-2025, 2025. a, b, c, d, e, f, g, h, i, j, k, l, m, n, o, p, q, r, s, t, u, v
Cziczo, D. J., Ladino, L., Boose, Y., Kanji, Z. A., Kupiszewski, P., Lance, S., Mertes, S., and Wex, H.: Measurements of Ice Nucleating Particles and Ice Residuals, Meteorol. Monogr., 58, 8.1–8.13, https://doi.org/10.1175/AMSMONOGRAPHS-D-16-0008.1, 2017. a
DeMott, P. J., Prenni, A. J., Liu, X., Kreidenweis, S. M., Petters, M. D., Twohy, C. H., Richardson, M. S., Eidhammer, T., and Rogers, D. C.: Predicting global atmospheric ice nuclei distributions and their impacts on climate, P. Natl. Acad. Sci. USA, 107, 11217–11222, https://doi.org/10.1073/pnas.0910818107, 2010. a
Engelmann, R., Althausen, D., Baars, H., Griesche, H., Hofer, J., Radenz, M., and Seifert, P.: Custom collection of categorize data from RV Polarstern between 11 Oct 2019 and 30 Sep 2020, ACTRIS Cloud remote sensing data centre unit (CLU) [data set], https://doi.org/10.60656/00945b67503743f0, 2023. a
Haag, W. and Kärcher, B.: The impact of aerosols and gravity waves on cirrus clouds at midlatitudes, J. Geophys. Res.-Atmos., 109, D12202, https://doi.org/10.1029/2004JD004579, 2004. a
Heymsfield, A. J., Krämer, M., Luebke, A., Brown, P., Cziczo, D. J., Franklin, C., Lawson, P., Lohmann, U., McFarquhar, G., Ulanowski, Z., and Tricht, K. V.: Cirrus Clouds, Meteorol. Monogr., 58, 2.1–2.26, https://doi.org/10.1175/AMSMONOGRAPHS-D-16-0010.1, 2017. a
Kanji, Z. A., Florea, O., and Abbatt, J. P. D.: Ice formation via deposition nucleation on mineral dust and organics: dependence of onset relative humidity on total particulate surface area, Environ. Res. Lett., 3, 025004, https://doi.org/10.1088/1748-9326/3/2/025004, 2008. a, b
Kärcher, B. and Lohmann, U.: A parameterization of cirrus cloud formation: Homogeneous freezing of supercooled aerosols, J. Geophys. Res.-Atmos., 107, AAC4-1–AAC4-10, https://doi.org/10.1029/2001JD000470, 2002. a, b
Kärcher, B. and Podglajen, A.: A Stochastic Representation of Temperature Fluctuations Induced by Mesoscale Gravity Waves, J. Geophys. Res.-Atmos., 124, 11506–11529, https://doi.org/10.1029/2019JD030680, 2019. a, b
Kärcher, B., Jensen, E. J., and Lohmann, U.: The Impact of Mesoscale Gravity Waves on Homogeneous Ice Nucleation in Cirrus Clouds, Geophys. Res. Lett., 46, 5556–5565, https://doi.org/10.1029/2019GL082437, 2019. a
Kärcher, B., DeMott, P. J., Jensen, E. J., and Harrington, J. Y.: Studies on the Competition Between Homogeneous and Heterogeneous Ice Nucleation in Cirrus Formation, J. Geophys. Res.-Atmos., 127, e2021JD035805, https://doi.org/10.1029/2021JD035805, 2022. a, b, c, d
Kärcher, B., Jensen, E. J., Pokrifka, G. F., and Harrington, J. Y.: Ice Supersaturation Variability in Cirrus Clouds: Role of Vertical Wind Speeds and Deposition Coefficients, J. Geophys. Res.-Atmos., 128, e2023JD039324, https://doi.org/10.1029/2023JD039324, 2023. a, b, c
Khvorostyanov, V. I. and Curry, J. A.: Fall Velocities of Hydrometeors in the Atmosphere: Refinements to a Continuous Analytical Power Law, J. Atmos. Sci., 62, 4343–4357, https://doi.org/10.1175/JAS3622.1, 2005. a
Knopf, D. A. and Alpert, P. A.: A water activity based model of heterogeneous ice nucleation kinetics for freezing of water and aqueous solution droplets, Farad. Discuss., 165, 513–534, https://doi.org/10.1039/c3fd00035d, 2013. a
Knopf, D. A. and Alpert, P. A.: Atmospheric ice nucleation, Nat. Rev. Phys., 5, 203–217, https://doi.org/10.1038/s42254-023-00570-7, 2023. a
Knopf, D. A. and Rigg, Y. J.: Homogeneous Ice Nucleation From Aqueous Inorganic/Organic Particles Representative of Biomass Burning: Water Activity, Freezing Temperatures, Nucleation Rates, The J. Phys. Chem. A, 115, 762–773, https://doi.org/10.1021/jp109171g, pMID: 21235213, 2011. a, b
Knopf, D. A., Alpert, P. A., and Wang, B.: The role of organic aerosol in atmospheric ice nucleation: a review, ACS Earth Space Chem., 2, 168–202, https://doi.org/10.1021/acsearthspacechem.7b00120, 2018. a, b, c
Knopf, D. A., Wang, P., Wong, B., Tomlin, J. M., Veghte, D. P., Lata, N. N., China, S., Laskin, A., Moffet, R. C., Aller, J. Y., Marcus, M. A., and Wang, J.: Physicochemical characterization of free troposphere and marine boundary layer ice-nucleating particles collected by aircraft in the eastern North Atlantic, Atmos. Chem. Phys., 23, 8659–8681, https://doi.org/10.5194/acp-23-8659-2023, 2023b. a
Koop, T. and Zobrist, B.: Parameterizations for ice nucleation in biological and atmospheric systems, Phys. Chem. Chem. Phys., 11, 10839–10850, https://doi.org/10.1039/B914289D, 2009. a
Koop, T., Luo, B. P., Tsias, A., and Peter, T.: Water activity as the determinant for homogeneous ice nucleation in aqueous solutions, Nature, 406, 611–614, https://doi.org/10.1038/35020537, 2000. a, b
Krämer, M., Rolf, C., Luebke, A., Afchine, A., Spelten, N., Costa, A., Meyer, J., Zöger, M., Smith, J., Herman, R. L., Buchholz, B., Ebert, V., Baumgardner, D., Borrmann, S., Klingebiel, M., and Avallone, L.: A microphysics guide to cirrus clouds – Part 1: Cirrus types, Atmos. Chem. Phys., 16, 3463–3483, https://doi.org/10.5194/acp-16-3463-2016, 2016. a, b, c
Kuebbeler, M., Lohmann, U., Hendricks, J., and Kärcher, B.: Dust ice nuclei effects on cirrus clouds, Atmos. Chem. Phys., 14, 3027–3046, https://doi.org/10.5194/acp-14-3027-2014, 2014. a
Lohmann, U., Lüönd, F., and Mahrt, F.: An Introduction to Clouds: From the Microscale to Climate, Cambridge University Press, https://doi.org/10.1017/CBO9781139087513, 2016. a, b, c
Maturilli, M., Holdridge, D. J., Dahlke, S., Graeser, J., Sommerfeld, A., Jaiser, R., Deckelmann, H., and Schulz, A.: Initial radiosonde data from 2019-10 to 2020-09 during project MOSAiC, PANGAEA [data set], https://doi.org/10.1594/PANGAEA.928656, 2021. a
Maturilli, M., Sommer, M., Holdridge, D. J., Dahlke, S., Graeser, J., Sommerfeld, A., Jaiser, R., Deckelmann, H., and Schulz, A.: MOSAiC radiosonde data (level 3) [dataset publication series], Pangaea, https://doi.org/10.1594/PANGAEA.943870, 2022. a, b
Murray, B. J., Wilson, T. W., Dobbie, S., and Cui, Z.: Heterogeneous nucleation of ice particles on glassy aerosols under cirrus conditions, Nat. Geosci., 3, 233–237, https://doi.org/10.1038/ngeo817, 2010. a
Nixdorf, U., Dethloff, K., Rex, M., Shupe, M., Sommerfeld, A., Perovich, D., Nicolaus, M., Heuzé, C., Rabe, B., Loose, B., Damm, E., Gradinger, R., Fong., A, Maslowski, W., Rinke, A., Kwok, R., Spreen, G., Wendisch, M., Herber, A., Hirsekorn, M., Mohaupt, V., Frickenhaus, S., Immerz, A., Weiss-Tuider, K., König, B., Mengedoht, D., Regnery, J., Gerchow, P., Ransby, D., Krumpen, T., Morgenstern, A., Haas, C., Kanzow, T., Rack, F. R., Saitzev, V., Sokolov, V., Makarov, A., Schwarze, S., Wunderlich, T., Wurr, K., and Boetius, A.: MOSAiC extended acknowledgement, Zenodo, https://doi.org/10.5281/zenodo.5179738, 2021. a
Ohneiser, K., Ansmann, A., Baars, H., Seifert, P., Barja, B., Jimenez, C., Radenz, M., Teisseire, A., Floutsi, A., Haarig, M., Foth, A., Chudnovsky, A., Engelmann, R., Zamorano, F., Bühl, J., and Wandinger, U.: Smoke of extreme Australian bushfires observed in the stratosphere over Punta Arenas, Chile, in January 2020: optical thickness, lidar ratios, and depolarization ratios at 355 and 532 nm, Atmos. Chem. Phys., 20, 8003–8015, https://doi.org/10.5194/acp-20-8003-2020, 2020. a
Ohneiser, K., Ansmann, A., Chudnovsky, A., Engelmann, R., Ritter, C., Veselovskii, I., Baars, H., Gebauer, H., Griesche, H., Radenz, M., Hofer, J., Althausen, D., Dahlke, S., and Maturilli, M.: The unexpected smoke layer in the High Arctic winter stratosphere during MOSAiC 2019–2020, Atmos. Chem. Phys., 21, 15783–15808, https://doi.org/10.5194/acp-21-15783-2021, 2021a. a, b, c, d
Ohneiser, K., Ansmann, A., Engelmann, R., Griesche, H., Radenz, M., Hofer, J., and Althausen, D.: Optical aerosol profiles from the Raman Lidar Polly-XT during MOSAiC, Pangaea [data set], https://doi.org/10.1594/PANGAEA.935539, 2021b. a
Ohneiser, K., Ansmann, A., Kaifler, B., Chudnovsky, A., Barja, B., Knopf, D. A., Kaifler, N., Baars, H., Seifert, P., Villanueva, D., Jimenez, C., Radenz, M., Engelmann, R., Veselovskii, I., and Zamorano, F.: Australian wildfire smoke in the stratosphere: the decay phase in 2020/2021 and impact on ozone depletion, Atmos. Chem. Phys., 22, 7417–7442, https://doi.org/10.5194/acp-22-7417-2022, 2022. a
Polly: PollyNET lidar data base, available at: http://polly.tropos.de/ (last access: 10 January 2024), 2024. a
Radenz, M., Bühl, J., Seifert, P., Baars, H., Engelmann, R., Barja González, B., Mamouri, R.-E., Zamorano, F., and Ansmann, A.: Hemispheric contrasts in ice formation in stratiform mixed-phase clouds: disentangling the role of aerosol and dynamics with ground-based remote sensing, Atmos. Chem. Phys., 21, 17969–17994, https://doi.org/10.5194/acp-21-17969-2021, 2021. a
Riechers, B., Wittbracht, F., Hütten, A., and Koop, T.: The homogeneous ice nucleation rate of water droplets produced in a microfluidic device and the role of temperature uncertainty, Phys. Chem. Chem. Phys., 15, 5873–5887, https://doi.org/10.1039/C3CP42437E, 2013. a
Rigg, Y. J., Alpert, P. A., and Knopf, D. A.: Immersion freezing of water and aqueous ammonium sulfate droplets initiated by humic-like substances as a function of water activity, Atmos. Chem. Phys., 13, 6603–6622, https://doi.org/10.5194/acp-13-6603-2013, 2013. a
Rolf, C., Krämer, M., Schiller, C., Hildebrandt, M., and Riese, M.: Lidar observation and model simulation of a volcanic-ash-induced cirrus cloud during the Eyjafjallajökull eruption, Atmos. Chem. Phys., 12, 10281–10294, https://doi.org/10.5194/acp-12-10281-2012, 2012. a
Schneider, J., Höhler, K., Wagner, R., Saathoff, H., Schnaiter, M., Schorr, T., Steinke, I., Benz, S., Baumgartner, M., Rolf, C., Krämer, M., Leisner, T., and Möhler, O.: High homogeneous freezing onsets of sulfuric acid aerosol at cirrus temperatures, Atmos. Chem. Phys., 21, 14403–14425, https://doi.org/10.5194/acp-21-14403-2021, 2021. a
Schröder, F., Kärcher, B., Fiebig, M., and Petzold, A.: Aerosol states in the free troposphere at northern midlatitudes, J. Geophys. Res.-Atmos., 107, LAC8-1–LAC8-8, https://doi.org/10.1029/2000JD000194, 2002. a
Shupe, M. D., Rex, M., Blomquist, B., Ola, P., Persson, G., Schmale, J., Uttal, T., Althausen, D., Angot, H., Archer, S., Bariteau, L., Beck, I., Bilberry, J., Bucci, S., Buck, C., Boyer, M., Brasseur, Z., Brooks, I. M., Calmer, R., Cassano, J., Castro, V., Chu, D., Costa, D., Cox, C. J., Creamean, J., Crewell, S., Dahlke, S., Damm, E., de Boer, G., Deckelmann, H., Dethloff, K., Dütsch, M., Ebell, K., Ehrlich, A., Ellis, J., Engelmann, R., Fong, A. A., Frey, M. M., Gallagher, M. R., Ganzeveld, L., Gradinger, R., Graeser, J., Greenamyer, V., Griesche, H., Griffiths, S., Hamilton, J., Heinemann, G., Helmig, D., Herber, A., Heuzé, C., Hofer, J., Houchens, T., Howard, D., Inoue, J., Jacobi, H.-W., Jaiser, R., Jokinen, T., Jourdan, O., Jozef, G., King, W., Kirchgaessner, A., Klingebiel, M., Krassovski, M., Krumpen, T., Lampert, A., Landing, W., Laurila, T., Lawrence, D., Lonardi, M., Loose, B., Lüpkes, C., Maahn, M., Macke, A., Maslowski, W., Marsay, C., Maturilli, M., Mech, M., Morris, S., Moser, M., Nicolaus, M., Ortega, P., Osborn, J., Pätzold, F., Perovich, D. K., Petäjä, T., Pilz, C., Pirazzini, R., Posman, K., Powers, H., Pratt, K. A., Preußer, A., Quéléver, L., Radenz, M., Rabe, B., Rinke, A., Sachs, T., Schulz, A., Siebert, H., Silva, T., Solomon, A., Sommerfeld, A., Spreen, G., Stephens, M., Stohl, A., Svensson, G., Uin, J., Viegas, J., Voigt, C., von der Gathen, P., Wehner, B., Welker, J. M., Wendisch, M., Werner, M., Xie, Z., and Yue, F.: Overview of the MOSAiC expedition: Atmosphere, Elementa: Sci. Anthrop., 10, 00060, https://doi.org/10.1525/elementa.2021.00060, 2022. a
Skrotzki, J., Connolly, P., Schnaiter, M., Saathoff, H., Möhler, O., Wagner, R., Niemand, M., Ebert, V., and Leisner, T.: The accommodation coefficient of water molecules on ice – cirrus cloud studies at the AIDA simulation chamber, Atmos. Chem. Phys., 13, 4451–4466, https://doi.org/10.5194/acp-13-4451-2013, 2013. a, b, c, d, e, f
Spichtinger, P. and Cziczo, D. J.: Impact of heterogeneous ice nuclei on homogeneous freezing events in cirrus clouds, J. Geophys. Res.-Atmos., 115, D14208, https://doi.org/10.1029/2009JD012168, 2010. a, b, c
Spichtinger, P. and Gierens, K. M.: Modelling of cirrus clouds – Part 1a: Model description and validation, Atmos. Chem. Phys., 9, 685–706, https://doi.org/10.5194/acp-9-685-2009, 2009. a
Spichtinger, P., Gierens, K., and Dörnbrack, A.: Formation of ice supersaturation by mesoscale gravity waves, Atmos. Chem. Phys., 5, 1243–1255, https://doi.org/10.5194/acp-5-1243-2005, 2005. a
Spichtinger, P., Marschalik, P., and Baumgartner, M.: Impact of formulations of the homogeneous nucleation rate on ice nucleation events in cirrus, Atmos. Chem. Phys., 23, 2035–2060, https://doi.org/10.5194/acp-23-2035-2023, 2023. a, b, c
Wang, B., Lambe, A. T., Massoli, P., Onasch, T. B., Davidovits, P., Worsnop, D. R., and Knopf, D. A.: The deposition ice nucleation and immersion freezing potential of amorphous secondary organic aerosol: Pathways for ice and mixed-phase cloud formation, J. Geophys. Res.-Atmos., 117, D16206, https://doi.org/10.1029/2012JD018063, 2012. a, b
Westbrook, C. D., Hogan, R. J., and Illingworth, A. J.: The Capacitance of Pristine Ice Crystals and Aggregate Snowflakes, J. Atmos. Sci., 65, 206–219, https://doi.org/10.1175/2007JAS2315.1, 2008. a
Wolf, M., Zhang, Y., Zawadowicz, M., Goodell, M., Froyd, K., Freney, E., Sellegri, K., Rösch, M., Cui, T., Winter, M., Lacher, L., Axisa, D., Axisa, D., DeMott, P. J., Levin, E., T., J., Gute, E., Abbatt, J., Koss, A., Kroll, J. H., Surratt, J. D., and Cziczo, D. J.: A biogenic secondary organic aerosol source of cirrus ice nucleating particles, Nat. Commun., 11, 4834, https://doi.org/10.1038/s41467-020-18424-6, 2020. a
Short summary
In this study, we focus on the potential impact of wildfire smoke on cirrus formation. Aerosol and cirrus observations with lidar and radar during the MOSAiC (Multidisciplinary drifting Observatory for the Study of Arctic Climate) expedition, presented in the companion paper (Ansmann et al., 2025), are closely linked to comprehensive modeling of ice nucleation in cirrus evolution processes, presented in this article. A clear impact of wildfire smoke on cirrus formation was found.
In this study, we focus on the potential impact of wildfire smoke on cirrus formation. Aerosol...
Altmetrics
Final-revised paper
Preprint