Articles | Volume 24, issue 8
https://doi.org/10.5194/acp-24-4591-2024
© Author(s) 2024. 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-24-4591-2024
© Author(s) 2024. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
18 Apr 2024
Research article |
| 18 Apr 2024
| 18 Apr 2024
Comparing the simulated influence of biomass burning plumes on low-level clouds over the southeastern Atlantic under varying smoke conditions
Alejandro Baró Pérez
CORRESPONDING AUTHOR
Department of Meteorology, Stockholm University, Stockholm, Sweden
Bolin Centre for Climate Research, Stockholm, Sweden
now at: Department of Space, Earth and Environment, Chalmers University, Gothenburg 41296, Sweden
Michael S. Diamond
Department of Earth, Ocean, & Atmospheric Science, Florida State University, Tallahassee, FL, USA
Frida A.-M. Bender
Department of Meteorology, Stockholm University, Stockholm, Sweden
Bolin Centre for Climate Research, Stockholm, Sweden
Abhay Devasthale
Meteorological Research Unit, Research and Development, Swedish Meteorological and Hydrological Institute, Norrköping, Sweden
Matthias Schwarz
GeoSphere Austria, Hohe Warte 38, 1190 Vienna, Austria
Julien Savre
Meteorological Institute, Fakultät für Physik, Ludwig-Maximilians-Universität Munich, 80333 Munich, Germany
Juha Tonttila
Finnish Meteorological Institute, Kuopio, Finland
Harri Kokkola
Finnish Meteorological Institute, Kuopio, Finland
Hyunho Lee
Department of Atmospheric Science, Kongju National University, Gongju 32588, South Korea
David Painemal
NASA Langley Research Center, Hampton, Virginia, USA
Annica M. L. Ekman
Department of Meteorology, Stockholm University, Stockholm, Sweden
Bolin Centre for Climate Research, Stockholm, Sweden
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Michael S. Diamond, Andrew S. Ackerman, Alejandro Baró Pérez, Ann M. Fridlind, Ehsan Erfani, Caspar Jungbacker, Hyunho Lee, David Painemal, Frida A.-M. Bender, Annica M. L. Ekman, Franziska Glassmeier, Graham Feingold, Fredrik Jansson, David A. Johnson, Matthias Schwarz, Robert Wood, Takanobu Yamaguchi, Jianhao Zhang, Xiaoli Zhou, and Paquita Zuidema
EGUsphere, https://doi.org/10.5194/egusphere-2026-5350, https://doi.org/10.5194/egusphere-2026-5350, 2026
This preprint is open for discussion and under review for Atmospheric Chemistry and Physics (ACP).
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We compare how cloud resolving models represent an important cloud transition over the subtropical oceans. Clouds can either break up by deepening and drying out or by raining and forming an open cell pattern. Compared to observations, the clouds deepen a bit too much and get too polluted when smoke is present. In clean conditions, some models drizzle and break up into open cells while others barely rain; the model spread stems from different rain amounts for similar clouds.
Dominic Heslin-Rees, Peter Tunved, Diego Aliaga, Janne Lampilahti, Ilona Riipinen, Annica M. L. Ekman, Ki-Tae Park, Martina Mazzini, Stefania Gilardoni, Roseline Thakur, Kihong Park, Young Jun Yoon, Kitack Lee, Mikko Sipilä, Mauro Mazzola, and Radovan Krejci
Aerosol Research, 4, 457–483, https://doi.org/10.5194/ar-4-457-2026, https://doi.org/10.5194/ar-4-457-2026, 2026
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New particles form in the atmosphere and can influence the climate. We studied Arctic new particle formation (NPF) from 2022 to 2024 at the Zeppelin Observatory, on Svalbard. NPF occurs from April to November, peaking in late spring as sunlight increases. Some particles measured on-site grow large enough to seed clouds. Sunlight and existing aerosol particles strongly impact the likelihood of NPF, which mainly originates from marine regions, particularly the Greenland Sea.
Kanika Taneja, Silvia M. Calderón, Harri Kokkola, Juha Tonttila, Sami Romakkaniemi, Seethala Chellappan, Antti Arola, Antti Lipponen, Taina Yli-Juuti, Snehitha M. Kommula, Tuukka Petäjä, Markku Kulmala, and Tero Mielonen
EGUsphere, https://doi.org/10.5194/egusphere-2026-4750, https://doi.org/10.5194/egusphere-2026-4750, 2026
This preprint is open for discussion and under review for Atmospheric Chemistry and Physics (ACP).
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Vegetation can cool the climate by releasing gases that form aerosols, which scatter sunlight and brighten clouds. To quantify this feedback in Finland and the United States, we combine field measurements of aerosols and satellite observations of clouds. It is essential to select near-ideal clouds; otherwise, cloud-related cooling is underestimated. Cloud cooling matched aerosol cooling at the clean site in Finland and was nearly three times stronger at the rural site in the United States.
Timothy W. Juliano, Florian Tornow, Ann M. Fridlind, Andrew S. Ackerman, Gregory S. Elsaesser, Bart Geerts, Christian P. Lackner, David Painemal, Israel Silber, Mikhail Ovchinnikov, Gunilla Svensson, Michael Tjernström, Peng Wu, Alejandro Baró Pérez, Peter Bogenschutz, Dmitry Chechin, Kamal Kant Chandrakar, Jan Chylik, Andrey Debolskiy, Rostislav Fadeev, Anu Gupta, Luisa Ickes, Michail Karalis, Martin Köhler, Branko Kosović, Peter Kuma, Weiwei Li, Evgeny Mortikov, Hugh Morrison, Roel A. J. Neggers, Anna Possner, Tomi Raatikainen, Lea Raillard, Sami Romakkaniemi, Niklas Schnierstein, Shin-ichiro Shima, Nikita Silin, Mikhail Tolstykh, Étienne Vignon, Lulin Xue, Meng Zhang, and Xue Zheng
Atmos. Chem. Phys., 26, 13267–13302, https://doi.org/10.5194/acp-26-13267-2026, https://doi.org/10.5194/acp-26-13267-2026, 2026
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Models struggle to capture cloud and precipitation processes and their radiative effects in marine cold-air outbreaks. We use a quasi-Lagrangian framework to compare large-eddy simulation (LES) and single-column model (SCM) output with field and satellite observations. With fixed droplet and ice numbers, LES and SCM agree in liquid-only tests. In mixed-phase conditions, LES plausibly capture cloud thinning and breakup, while SCMs largely remain overcast and thereby miss cloud radiative effects.
Haruki Hirasawa, Knut von Salzen, Matthew Henry, Josh Smith, Frida A.-M. Bender, Cindy Wang, Sarah Doherty, Robert Wood, Philip J. Rasch, and James Haywood
EGUsphere, https://doi.org/10.5194/egusphere-2026-5460, https://doi.org/10.5194/egusphere-2026-5460, 2026
This preprint is open for discussion and under review for Atmospheric Chemistry and Physics (ACP).
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Marine cloud brightening (MCB) is a solar climate intervention proposal to spray sea salt aerosol (SSA) to increase sunlight reflection by low marine clouds. Earth System Models (ESMs) are our main tool for studying potential MCB climate impacts, but there is a large range across ESMs in the MCB sunlight reflection. Comparing MCB in ten ESMs, we find that much of this range is from the size of the SSA and cloud droplet formation from the SSA, both relatively well understood processes.
Liine Heikkinen, Rahul Ranjan, Sini Talvinen, Niels Behr, Sara M. Blichner, Maura Dewey, Lauri R. Ahonen, Mikael Ehn, Annica M. L. Ekman, Radovan Krejci, Tuukka Petäjä, Peter Tunved, and Ilona Riipinen
EGUsphere, https://doi.org/10.5194/egusphere-2026-5082, https://doi.org/10.5194/egusphere-2026-5082, 2026
This preprint is open for discussion and under review for Atmospheric Chemistry and Physics (ACP).
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The impacts of clouds on atmospheric particulate matter (PM) composition are not well understood. Here, we use a new method to infer these interactions as particle number size distributions with bimodal shapes serve as markers of chemical cloud processing. Using concurrent PM composition data from a boreal forest in Finland, we find cloud chemistry to enrich PM in sulfate, but no enhanced formation of organics was observed, despite the abundance of precursors emitted by the forest.
Almuth Neuberger, Rahul Ranjan, Hao Ding, Fredrik Mattsson, Lea Haberstock, Darrel Baumgardner, Stefano Decesari, Annica M. L. Ekman, Dagen D. Hughes, Claudia Mohr, Marco Paglione, Ilona Riipinen, Matteo Rinaldi, and Paul Zieger
Atmos. Chem. Phys., 26, 11991–12017, https://doi.org/10.5194/acp-26-11991-2026, https://doi.org/10.5194/acp-26-11991-2026, 2026
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We studied how particles from air pollution that absorb water but do not yet form fog droplets influence fog and visibility in northern Italy’s Po Valley. Using detailed field observations and computer modeling, we found that these “hydrated” particles can explain many low-visibility events. Recognizing their role helps improve forecasts of fog, air quality, and climate effects in polluted regions.
Jianyu Zheng, Hongbin Yu, Chamara Rajapakse, Mian Chin, Michael Schulz, Yves Balkanski, Susanne E. Bauer, Huisheng Bian, Peter Colarco, Dongchul Kim, Ramiro Checa-Garcia, Yevgeny Derimian, Oleg Dubovik, Paul Ginoux, Zak Kipling, Jasper F. Kok, Harri Kokkola, Philippe Le Sager, Lei Li, Marianne Tronstad Lund, Gunnar Myhre, Hitoshi Matsui, Dirk J. L. Olivie, Samuel Remy, Oyvind Seland, Qianqian Song, Toshihiko Takemura, Qian Tan, Kostas Tsigaridis, Twan van Noije, David Winker, Bin Xie, Hua Zhang, Xindan Zhang, and Zhibo Zhang
EGUsphere, https://doi.org/10.5194/egusphere-2026-4322, https://doi.org/10.5194/egusphere-2026-4322, 2026
This preprint is open for discussion and under review for Atmospheric Chemistry and Physics (ACP).
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Winds carry vast amounts of Saharan dust across the Atlantic Ocean, influencing climate, air quality, and ocean ecosystems. Within the Aerosol Comparisons between Observations and Models (AeroCom) project, we evaluated 17 numerical models against observations. Models deposit dust too quickly, so too little reaches the Caribbean. Better simulations require emitting larger particles, treating their non-spherical shapes, and capturing processes that keep dust aloft during transport.
Sara M. Blichner, Theodore Khadir, Sini Talvinen, Paulo Artaxo, Liine Heikkinen, Harri Kokkola, Radovan Krejci, Muhammed Irfan, Twan van Noije, Tuukka Petäjä, Christopher Pöhlker, Øyvind Seland, Carl Svenhag, Antti Vartiainen, and Ilona Riipinen
Atmos. Chem. Phys., 26, 11281–11307, https://doi.org/10.5194/acp-26-11281-2026, https://doi.org/10.5194/acp-26-11281-2026, 2026
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This study looks at how well climate models capture the impact of rain on particles that help form cloud droplets. Using data from three measurement stations and applying both a correlation analysis and a machine learning approach, we found that models often miss how new particles form after rain and struggle in cold environments. This matters because these particles influence cloud formation and climate.
William Wandji Nyamsi, Ville Leinonen, Antti Lipponen, Else van den Besselaar, Santtu Mikkonen, Arturo Sanchez-Lorenzo, Martin Wild, Doris Folini, Tero Mielonen, Harri Kokkola, Antti Kukkurainen, Neus Sabater, Rei Kudo, Ben Liley, Raghav Srinivasan, Bruce W. Forgan, Alexandru Dumitrescu, Grzegorz Urban, Michał K. Kowalewski, Márcia Akemi Yamasoe, Nilton Évora do Rosário, Dimitra Founda, Stelios Kazadzis, Veronica Manara, Derbetini A. Vondou, Christian Gueymard, Anders V. Lindfors, Atsumu Ohmura, and Antti Arola
Atmos. Chem. Phys., 26, 10767–10788, https://doi.org/10.5194/acp-26-10767-2026, https://doi.org/10.5194/acp-26-10767-2026, 2026
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Worldwide reconstructed historical aerosol load reveals that during the period of:
- 1900–1959: the atmosphere became cleaner in most European cities;
- 1960–1985: anthropogenic aerosols were responsible for the dimming phenomenon in Europe. AOD increased over Southeast Brazil and decreased noticeably over Japan while a small negative trend was found over Oceania;
- 1986–2015: generally, the atmosphere has become much cleaner everywhere after the reversal trend around 1980s mainly observed in Europe.
Hao Ding, Almuth Neuberger, Rahul Ranjan, Fredrik Mattsson, Liine Heikkinen, Karam Mansour, Stefano Decesari, Claudia Mohr, Alejandro Baró Pérez, Nazario Mastroianni, Paul Zieger, Ilona Riipinen, and Annica M. L. Ekman
Atmos. Chem. Phys., 26, 9721–9739, https://doi.org/10.5194/acp-26-9721-2026, https://doi.org/10.5194/acp-26-9721-2026, 2026
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Fog poses numerous risks to society, yet it remains challenging to forecast. We use detailed numerical simulations based on fog observations in the Po Valley, Italy, to demonstrate that high concentrations of aerosol particles, as in polluted air, lead to an increase in droplet number, prolonged fog duration, and reduced visibility. The simulations also show the importance of accurately representing haze particles and the shape of the droplet size distribution for improved fog prediction.
Zhujun Li, David Painemal, Yan Feng, and Xiaojian Zheng
Atmos. Chem. Phys., 26, 7705–7720, https://doi.org/10.5194/acp-26-7705-2026, https://doi.org/10.5194/acp-26-7705-2026, 2026
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This study is the first global assessment of aerosol-cloud interactions (ACI) and cloud adjustments that relies on vertically resolved aerosol retrievals that are vertically matched with the location of the cloud layer. We computed ACI metrics and cloud adjustments over the global ocean by combining retrievals from active and passive satellite sensors and found high sensitivity of clouds to changes in their cloud droplet number concentration due to aerosols.
Jianhao Zhang, David Painemal, Tom Dror, Jung-Sub Lim, Armin Sorooshian, and Graham Feingold
Atmos. Chem. Phys., 26, 6015–6034, https://doi.org/10.5194/acp-26-6015-2026, https://doi.org/10.5194/acp-26-6015-2026, 2026
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Clouds transitioning from overcast to broken fields play an important role in regulating the amount of sunlight reaching Earth’s surface. Using satellite imagery and a novel space-time exchange approach, we examine these transitions during marine cold-air outbreaks. Our analysis reveals characteristic signatures (or fingerprints) of liquid- and ice-phase processes, demonstrating how space-borne observations can provide new physical insight into cloud evolution.
Anna Granberg, Vilma Lundholm, Pouria Khalaj, Manu Anna Thomas, Yifan Ding, Daniel Jönsson, and Abhay Devasthale
EGUsphere, https://doi.org/10.5194/egusphere-2026-915, https://doi.org/10.5194/egusphere-2026-915, 2026
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This study explores the potential of machine learning models to classify mesoscale low-level cloud patterns frequently observed in the trade wind regions of the Atlantic Ocean. These clouds significantly influence the Earth's climate. This study is the first of its kind to establish a framework for classifying these shallow clouds – currently parameterized in global climate models and offers a framework that can be integrated into such models to reduce uncertainties in the climate projections.
Paul Glantz, Kevin James Noone, Abhay Devasthale, and Frederik Schenk
EGUsphere, https://doi.org/10.5194/egusphere-2026-1654, https://doi.org/10.5194/egusphere-2026-1654, 2026
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Terrestrial warming rates, divergent to oceans, have accelerated substantially since 1980. Decreases in relative humidity, cloud cover and precipitation in addition to dryer land conditions is a strong indication of perturbed surface water balance that is driven by increases in absorbed infrared and solar radiation at the land surface. An amplifying feedback loop involving humidity, clouds, and solar radiation has likely contributed to the rapid terrestrial warming under global climate change.
Seethala Chellappan, David Painemal, Mandana Thieman, Christian Pelayo, William L. Smith Jr., and Lynn M. Russell
EGUsphere, https://doi.org/10.5194/egusphere-2026-933, https://doi.org/10.5194/egusphere-2026-933, 2026
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We analyzed observations from the ARM EPCAPE campaign at coastal California, and satellite cloud properties to understand how large-scale weather patterns influence marine low clouds and aerosols. Using ERA5 data and Self-Organizing Maps, we identified nine synoptic regimes linked to cloud cover, depth, and liquid water path. Satellite data show anticyclone position strongly affects cloud properties, while aerosol–cloud covariability depends on turbulence and supersaturation.
Jingyi Chen, Hailong Wang, Bo Zhang, Hongyu Liu, David Painemal, Armin Sorooshian, Sheng-Lun Tai, and Christiane Voigt
Atmos. Chem. Phys., 26, 2209–2224, https://doi.org/10.5194/acp-26-2209-2026, https://doi.org/10.5194/acp-26-2209-2026, 2026
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NASA-validated modeling shows +4K SST (sea surface temperature) & +25 % gradients distinctly alter boundary layer dynamics, cloud physics in cold-air outbreaks. Warmer SST reduces cloud cover; increases size, elongation; hydrometeors shift to ice. Sharper Gradients boost liquid water (cold upwind); reduces ice; disrupts organization. Also, SST changes alter cloud-top properties via entrained airmass origin. Resolving ocean-atmosphere coupling in global models is essential for accurate cloud feedback projections.
Timothy W. Juliano, Florian Tornow, Ann M. Fridlind, Andrew S. Ackerman, Gregory S. Elsaesser, Bart Geerts, Christian P. Lackner, David Painemal, Israel Silber, Mikhail Ovchinnikov, Gunilla Svensson, Michael Tjernström, Peng Wu, Alejandro Baró Pérez, Peter Bogenschutz, Dmitry Chechin, Kamal Kant Chandrakar, Jan Chylik, Andrey Debolskiy, Rostislav Fadeev, Anu Gupta, Luisa Ickes, Michail Karalis, Martin Köhler, Branko Kosović, Peter Kuma, Weiwei Li, Evgeny Mortikov, Hugh Morrison, Roel A. J. Neggers, Anna Possner, Tomi Raatikainen, Sami Romakkaniemi, Niklas Schnierstein, Shin-ichiro Shima, Nikita Silin, Mikhail Tolstykh, Lulin Xue, Meng Zhang, and Xue Zheng
EGUsphere, https://doi.org/10.5194/egusphere-2025-6217, https://doi.org/10.5194/egusphere-2025-6217, 2026
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Models struggle to capture cloud and precipitation processes and their radiative effects in marine cold-air outbreaks. We use a quasi-Lagrangian framework to compare large-eddy simulation (LES) and single-column model (SCM) output with field and satellite observations. With fixed droplet and ice numbers, LES and SCM agree in liquid-only tests. In mixed-phase conditions, LES plausibly capture cloud thinning and breakup, while SCMs largely remain overcast and thereby miss cloud radiative effects.
Xiaojian Zheng, Yan Feng, David Painemal, Meng Zhang, Shaocheng Xie, Zhujun Li, Robert Jacob, and Bethany Lusch
Atmos. Chem. Phys., 25, 17473–17499, https://doi.org/10.5194/acp-25-17473-2025, https://doi.org/10.5194/acp-25-17473-2025, 2025
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This study used satellite observations and climate model simulations to examine how aerosols affect marine clouds over the Eastern North Atlantic. Cloud responses to aerosols differed significantly across meteorological regimes. The model captured overall trends but exaggerated cloud responses, performing better for shallower than deeper clouds. The results highlight the need to untangle aerosol effects from meteorology and improve cloud process representation in climate models.
Rahul Ranjan, Maura Dewey, Liine Heikkinen, Lauri R. Ahonen, Krista Luoma, Paul Bowen, Tuukka Petäjä, Annica M. L. Ekman, Daniel G. Partridge, and Ilona Riipinen
Atmos. Chem. Phys., 25, 17275–17300, https://doi.org/10.5194/acp-25-17275-2025, https://doi.org/10.5194/acp-25-17275-2025, 2025
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We use multi-year measurements of cloud condensation nuclei (CCN) at a boreal forest site to inversely infer size-resolved aerosol chemical composition. We find that inorganic species are more enriched in the larger end (accumulation mode) of the sub-micron aerosol population while organics often dominate the smaller end (Aitken mode). Our approach demonstrates the potential of long-term CCN measurements to infer size-resolved chemical composition of sub-micron aerosol.
Michael S. Diamond and Lili F. Boss
Atmos. Chem. Phys., 25, 16401–16409, https://doi.org/10.5194/acp-25-16401-2025, https://doi.org/10.5194/acp-25-16401-2025, 2025
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Militia attacks on ships in the Red Sea disrupted container ship traffic in 2024. We use these traffic changes to quantify how the cloud-altering properties of ship pollution decreased following sulfur regulations in 2020 with measurements of two types of ship pollution, one of which is sensitive to fuel composition and another which is not. Near Africa, cloud changes in 2024 were nearly as large as before the regulations, but only one-third as strong after accounting for increased traffic.
Travis D. Toth, Marian B. Clayton, Zhujun Li, David Painemal, Sharon D. Rodier, Jayanta Kar, Tyler J. Thorsen, Richard A. Ferrare, Mark A. Vaughan, Jason L. Tackett, Huisheng Bian, Mian Chin, Anne E. Garnier, Ellsworth J. Welton, Robert A. Ryan, Charles R. Trepte, and David M. Winker
Atmos. Meas. Tech., 18, 6765–6793, https://doi.org/10.5194/amt-18-6765-2025, https://doi.org/10.5194/amt-18-6765-2025, 2025
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NASA's CALIPSO satellite mission observed aerosols (airborne particles) globally from 2006 to 2023. Its final data products update improves its aerosol optical parameters over oceans by adjusting for regional and seasonal differences in a new measurement-model synergistic approach. This results in a more realistic aerosol characterization, specifically near coastlines (where sea salt mixes with pollution), with potential impacts to future studies of science applications (e.g., climate effects).
Silvia M. Calderón, Noora Hyttinen, Harri Kokkola, Tomi Raatikainen, R. Paul Lawson, and Sami Romakkaniemi
Atmos. Chem. Phys., 25, 14479–14500, https://doi.org/10.5194/acp-25-14479-2025, https://doi.org/10.5194/acp-25-14479-2025, 2025
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Field campaigns suggest secondary ice production (SIP) from mm-sized supercooled droplets drives rapid glaciation and precipitation development in summer cumulus congestus clouds lacking ice-nucleating particles. Our large-eddy simulations with sectional aerosol–hydrometeor microphysics support this, reproducing observed size distributions and showing how SIP accelerates aggregation, enhancing surface precipitation.
Sini Talvinen, Paul Kim, Emanuele Tovazzi, Eemeli Holopainen, Roxana Cremer, Thomas Kühn, Harri Kokkola, Zak Kipling, David Neubauer, João C. Teixeira, Alistair Sellar, Duncan Watson-Parris, Yang Yang, Jialei Zhu, Srinath Krishnan, Annele Virtanen, and Daniel G. Partridge
Atmos. Chem. Phys., 25, 14449–14478, https://doi.org/10.5194/acp-25-14449-2025, https://doi.org/10.5194/acp-25-14449-2025, 2025
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Climate models struggle to predict how clouds and aerosols interact, affecting Earth’s energy balance. This study compares models to observations to see how they describe effects of clouds and rain on aerosols. While both models show similar overall trends, seasonal differences emerged. These, however, align with differences in key variables participating in cloud formation. The study provides insights on how to improve the representation of aerosol-cloud interactions in climate models.
Hans Segura, Xabier Pedruzo-Bagazgoitia, Philipp Weiss, Sebastian K. Müller, Thomas Rackow, Junhong Lee, Edgar Dolores-Tesillos, Imme Benedict, Matthias Aengenheyster, Razvan Aguridan, Gabriele Arduini, Alexander J. Baker, Jiawei Bao, Swantje Bastin, Eulàlia Baulenas, Tobias Becker, Sebastian Beyer, Hendryk Bockelmann, Nils Brüggemann, Lukas Brunner, Suvarchal K. Cheedela, Sushant Das, Jasper Denissen, Ian Dragaud, Piotr Dziekan, Madeleine Ekblom, Jan Frederik Engels, Monika Esch, Richard Forbes, Claudia Frauen, Lilli Freischem, Diego García-Maroto, Philipp Geier, Paul Gierz, Álvaro González-Cervera, Katherine Grayson, Matthew Griffith, Oliver Gutjahr, Helmuth Haak, Ioan Hadade, Kerstin Haslehner, Shabeh ul Hasson, Jan Hegewald, Lukas Kluft, Aleksei Koldunov, Nikolay Koldunov, Tobias Kölling, Shunya Koseki, Sergey Kosukhin, Josh Kousal, Peter Kuma, Arjun U. Kumar, Rumeng Li, Nicolas Maury, Maximilian Meindl, Sebastian Milinski, Kristian Mogensen, Bimochan Niraula, Jakub Nowak, Divya Sri Praturi, Ulrike Proske, Dian Putrasahan, René Redler, David Santuy, Domokos Sármány, Reiner Schnur, Patrick Scholz, Dmitry Sidorenko, Dorian Spät, Birgit Sützl, Daisuke Takasuka, Adrian Tompkins, Alejandro Uribe, Mirco Valentini, Menno Veerman, Aiko Voigt, Sarah Warnau, Fabian Wachsmann, Marta Wacławczyk, Nils Wedi, Karl-Hermann Wieners, Jonathan Wille, Marius Winkler, Yuting Wu, Florian Ziemen, Janos Zimmermann, Frida A.-M. Bender, Dragana Bojovic, Sandrine Bony, Simona Bordoni, Patrice Brehmer, Marcus Dengler, Emanuel Dutra, Saliou Faye, Erich Fischer, Chiel van Heerwaarden, Cathy Hohenegger, Heikki Järvinen, Markus Jochum, Thomas Jung, Johann H. Jungclaus, Noel S. Keenlyside, Daniel Klocke, Heike Konow, Martina Klose, Szymon Malinowski, Olivia Martius, Thorsten Mauritsen, Juan Pedro Mellado, Theresa Mieslinger, Elsa Mohino, Hanna Pawłowska, Karsten Peters-von Gehlen, Abdoulaye Sarré, Pajam Sobhani, Philip Stier, Lauri Tuppi, Pier Luigi Vidale, Irina Sandu, and Bjorn Stevens
Geosci. Model Dev., 18, 7735–7761, https://doi.org/10.5194/gmd-18-7735-2025, https://doi.org/10.5194/gmd-18-7735-2025, 2025
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The Next Generation of Earth Modeling Systems project (nextGEMS) developed two Earth system models that use horizontal grid spacing of 10 km and finer, giving more fidelity to the representation of local phenomena, globally. In its fourth cycle, nextGEMS simulated the Earth System climate over the 2020–2049 period under the SSP3-7.0 scenario. Here, we provide an overview of nextGEMS, insights into the model development, and the realism of multi-decadal, kilometer-scale simulations.
Tuomas Naakka, Daniel Köhler, Kalle Nordling, Petri Räisänen, Marianne Tronstad Lund, Risto Makkonen, Joonas Merikanto, Bjørn H. Samset, Victoria A. Sinclair, Jennie L. Thomas, and Annica M. L. Ekman
Atmos. Chem. Phys., 25, 8127–8145, https://doi.org/10.5194/acp-25-8127-2025, https://doi.org/10.5194/acp-25-8127-2025, 2025
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The effects of warmer sea surface temperatures and decreasing sea ice cover on polar climates have been studied using four climate models with identical prescribed changes in sea surface temperatures and sea ice cover. The models predict similar changes in air temperature and precipitation in the polar regions in a warmer climate with less sea ice. However, the models disagree on how the atmospheric circulation, i.e. the large-scale winds, will change with warmer temperatures and less sea ice.
Abhay Devasthale, Sandra Andersson, Erik Engström, Frank Kaspar, Jörg Trentmann, Anke Duguay-Tetzlaff, Jan Fokke Meirink, Erik Kjellström, Tomas Landelius, Manu Anna Thomas, and Karl-Göran Karlsson
Earth Syst. Dynam., 16, 1169–1182, https://doi.org/10.5194/esd-16-1169-2025, https://doi.org/10.5194/esd-16-1169-2025, 2025
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By compositing trends in multiple climate variables, this study presents emerging regimes that are relevant for solar energy applications. It is shown that the favourable conditions for exploiting solar energy are emerging during spring and early summer. The study also underscores the increasingly important role of clouds in regulating surface solar radiation as the aerosol concentrations are decreasing over Europe and the societal value of satellite-based climate monitoring.
Jung-Sub Lim, Yign Noh, Hyunho Lee, and Fabian Hoffmann
Atmos. Chem. Phys., 25, 5313–5329, https://doi.org/10.5194/acp-25-5313-2025, https://doi.org/10.5194/acp-25-5313-2025, 2025
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Rain formation in warm clouds begins when small droplets collide, but this process can be slow without larger droplets. We used simulations to explore the role of bigger droplets, known as precipitation embryos, in triggering rain. We found that they speed up rain only when their size and number exceed a critical threshold. This threshold becomes larger when collisions are naturally efficient, such as in clouds with broad droplet size distributions or strong turbulence.
Florian Tornow, Ann Fridlind, George Tselioudis, Brian Cairns, Andrew Ackerman, Seethala Chellappan, David Painemal, Paquita Zuidema, Christiane Voigt, Simon Kirschler, and Armin Sorooshian
Atmos. Chem. Phys., 25, 5053–5074, https://doi.org/10.5194/acp-25-5053-2025, https://doi.org/10.5194/acp-25-5053-2025, 2025
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The recent NASA campaign ACTIVATE (Aerosol Cloud meTeorology Interactions oVer the western ATlantic Experiment) performed 71 tandem flights in mid-latitude marine cold-air outbreaks off the US eastern seaboard. We provide meteorological and cloud transition stage context, allowing us to identify days that are most suitable for Lagrangian modeling and analysis. Surveyed cloud properties show signatures of cloud microphysical processes, such as cloud-top entrainment and secondary ice formation.
Duncan Watson-Parris, Laura J. Wilcox, Camilla W. Stjern, Robert J. Allen, Geeta Persad, Massimo A. Bollasina, Annica M. L. Ekman, Carley E. Iles, Manoj Joshi, Marianne T. Lund, Daniel McCoy, Daniel M. Westervelt, Andrew I. L. Williams, and Bjørn H. Samset
Atmos. Chem. Phys., 25, 4443–4454, https://doi.org/10.5194/acp-25-4443-2025, https://doi.org/10.5194/acp-25-4443-2025, 2025
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In 2020, regulations by the International Maritime Organization aimed to reduce aerosol emissions from ships. These aerosols previously had a cooling effect, which the regulations might reduce, revealing more greenhouse gas warming. Here we find that, while there is regional warming, the global 2020–2040 temperature rise is only +0.03 °C. This small change is difficult to distinguish from natural climate variability, indicating the regulations have had a limited effect on observed warming to date.
Hongyu Liu, Bo Zhang, Richard H. Moore, Luke D. Ziemba, Richard A. Ferrare, Hyundeok Choi, Armin Sorooshian, David Painemal, Hailong Wang, Michael A. Shook, Amy Jo Scarino, Johnathan W. Hair, Ewan C. Crosbie, Marta A. Fenn, Taylor J. Shingler, Chris A. Hostetler, Gao Chen, Mary M. Kleb, Gan Luo, Fangqun Yu, Mark A. Vaughan, Yongxiang Hu, Glenn S. Diskin, John B. Nowak, Joshua P. DiGangi, Yonghoon Choi, Christoph A. Keller, and Matthew S. Johnson
Atmos. Chem. Phys., 25, 2087–2121, https://doi.org/10.5194/acp-25-2087-2025, https://doi.org/10.5194/acp-25-2087-2025, 2025
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We use the GEOS-Chem model to simulate aerosol distributions and properties over the western North Atlantic Ocean (WNAO) during the winter and summer deployments in 2020 of the NASA ACTIVATE mission. Model results are evaluated against aircraft, ground-based, and satellite observations. The improved understanding of life cycle, composition, transport pathways, and distribution of aerosols has important implications for characterizing aerosol–cloud–meteorology interactions over WNAO.
Harri Kokkola, Juha Tonttila, Silvia M. Calderón, Sami Romakkaniemi, Antti Lipponen, Aapo Peräkorpi, Tero Mielonen, Edward Gryspeerdt, Timo Henrik Virtanen, Pekka Kolmonen, and Antti Arola
Atmos. Chem. Phys., 25, 1533–1543, https://doi.org/10.5194/acp-25-1533-2025, https://doi.org/10.5194/acp-25-1533-2025, 2025
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Understanding how atmospheric aerosols affect clouds is a scientific challenge. One question is how aerosols affects the amount of cloud water. We used a cloud-scale model to study these effects on marine clouds. The study showed that variations in cloud properties and instrument noise can cause bias in satellite-derived cloud water content. However, our results suggest that for similar weather conditions with well-defined aerosol concentrations, satellite data can reliably track these effects.
Mariya Petrenko, Ralph Kahn, Mian Chin, Susanne E. Bauer, Tommi Bergman, Huisheng Bian, Gabriele Curci, Ben Johnson, Johannes W. Kaiser, Zak Kipling, Harri Kokkola, Xiaohong Liu, Keren Mezuman, Tero Mielonen, Gunnar Myhre, Xiaohua Pan, Anna Protonotariou, Samuel Remy, Ragnhild Bieltvedt Skeie, Philip Stier, Toshihiko Takemura, Kostas Tsigaridis, Hailong Wang, Duncan Watson-Parris, and Kai Zhang
Atmos. Chem. Phys., 25, 1545–1567, https://doi.org/10.5194/acp-25-1545-2025, https://doi.org/10.5194/acp-25-1545-2025, 2025
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We compared smoke plume simulations from 11 global models to each other and to satellite smoke amount observations aimed at constraining smoke source strength. In regions where plumes are thick and background aerosol is low, models and satellites compare well. However, the input emission inventory tends to underestimate in many places, and particle property and loss rate assumptions vary enormously among models, causing uncertainties that require systematic in situ measurements to resolve.
Luís Filipe Escusa dos Santos, Hannah C. Frostenberg, Alejandro Baró Pérez, Annica M. L. Ekman, Luisa Ickes, and Erik S. Thomson
Atmos. Chem. Phys., 25, 119–142, https://doi.org/10.5194/acp-25-119-2025, https://doi.org/10.5194/acp-25-119-2025, 2025
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The Arctic is experiencing enhanced surface warming. The observed decline in Arctic sea-ice extent is projected to lead to an increase in Arctic shipping activity, which may lead to further climatic feedbacks. Using an atmospheric model and results from marine engine experiments that focused on fuel sulfur content reduction and exhaust wet scrubbing, we investigate how ship exhaust particles influence the properties of Arctic clouds. Implications for radiative surface processes are discussed.
Alejandro Uribe, Frida A.-M. Bender, and Thorsten Mauritsen
Atmos. Chem. Phys., 24, 13371–13384, https://doi.org/10.5194/acp-24-13371-2024, https://doi.org/10.5194/acp-24-13371-2024, 2024
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Our study explores climate feedbacks, vital for understanding global warming. It links them to shifts in Earth's energy balance at the atmosphere's top due to natural temperature variations. It takes roughly 50 years to establish this connection. Combined satellite observations and reanalysis suggest that Earth cools more than expected under carbon dioxide influence. However, continuous satellite data until at least the mid-2030s are crucial for refining our understanding of climate feedbacks.
Manu Anna Thomas, Klaus Wyser, Shiyu Wang, Marios Chatziparaschos, Paraskevi Georgakaki, Montserrat Costa-Surós, Maria Gonçalves Ageitos, Maria Kanakidou, Carlos Pérez García-Pando, Athanasios Nenes, Twan van Noije, Philippe Le Sager, and Abhay Devasthale
Geosci. Model Dev., 17, 6903–6927, https://doi.org/10.5194/gmd-17-6903-2024, https://doi.org/10.5194/gmd-17-6903-2024, 2024
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Aerosol–cloud interactions occur at a range of spatio-temporal scales. While evaluating recent developments in EC-Earth3-AerChem, this study aims to understand the extent to which the Twomey effect manifests itself at larger scales. We find a reduction in the warm bias over the Southern Ocean due to model improvements. While we see footprints of the Twomey effect at larger scales, the negative relationship between cloud droplet number and liquid water drives the shortwave radiative effect.
Jutta Kesti, Ewan J. O'Connor, Anne Hirsikko, John Backman, Maria Filioglou, Anu-Maija Sundström, Juha Tonttila, Heikki Lihavainen, Hannele Korhonen, and Eija Asmi
Atmos. Chem. Phys., 24, 9369–9386, https://doi.org/10.5194/acp-24-9369-2024, https://doi.org/10.5194/acp-24-9369-2024, 2024
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The study combines aerosol particle measurements at the surface and vertical profiling of the atmosphere with a scanning Doppler lidar to investigate how particle transportation together with boundary layer evolution can affect particle and SO2 concentrations at the surface in the Arabian Peninsula region. The instrumentation enabled us to see elevated nucleation mode particle and SO2 concentrations at the surface when air masses transported from polluted areas are mixed in the boundary layer.
Muhammed Irfan, Thomas Kühn, Taina Yli-Juuti, Anton Laakso, Eemeli Holopainen, Douglas R. Worsnop, Annele Virtanen, and Harri Kokkola
Atmos. Chem. Phys., 24, 8489–8506, https://doi.org/10.5194/acp-24-8489-2024, https://doi.org/10.5194/acp-24-8489-2024, 2024
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The study examines how the volatility of semi-volatile organic compounds affects secondary organic aerosol (SOA) formation and climate. Our simulations show that uncertainties in these volatilities influence aerosol mass and climate impacts. Accurate representation of these compounds in climate models is crucial for predicting global climate patterns.
Ewan Crosbie, Luke D. Ziemba, Michael A. Shook, Taylor Shingler, Johnathan W. Hair, Armin Sorooshian, Richard A. Ferrare, Brian Cairns, Yonghoon Choi, Joshua DiGangi, Glenn S. Diskin, Chris Hostetler, Simon Kirschler, Richard H. Moore, David Painemal, Claire Robinson, Shane T. Seaman, K. Lee Thornhill, Christiane Voigt, and Edward Winstead
Atmos. Chem. Phys., 24, 6123–6152, https://doi.org/10.5194/acp-24-6123-2024, https://doi.org/10.5194/acp-24-6123-2024, 2024
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Marine clouds are found to clump together in regions or lines, readily discernible from satellite images of the ocean. While clustering is also a feature of deep storm clouds, we focus on smaller cloud systems associated with fair weather and brief localized showers. Two aircraft sampled the region around these shallow systems: one incorporated measurements taken within, adjacent to, and below the clouds, while the other provided a survey from above using remote sensing techniques.
Leong Wai Siu, Joseph S. Schlosser, David Painemal, Brian Cairns, Marta A. Fenn, Richard A. Ferrare, Johnathan W. Hair, Chris A. Hostetler, Longlei Li, Mary M. Kleb, Amy Jo Scarino, Taylor J. Shingler, Armin Sorooshian, Snorre A. Stamnes, and Xubin Zeng
Atmos. Meas. Tech., 17, 2739–2759, https://doi.org/10.5194/amt-17-2739-2024, https://doi.org/10.5194/amt-17-2739-2024, 2024
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An unprecedented 3-year aerosol dataset was collected from a recent NASA field campaign over the western North Atlantic Ocean, which offers a special opportunity to evaluate two state-of-the-art remote sensing instruments, one lidar and the other polarimeter, on the same aircraft. Special attention has been paid to validate aerosol optical depth data and their uncertainties when no reference dataset is available. Physical reasons for the disagreement between two instruments are discussed.
Anton Laakso, Daniele Visioni, Ulrike Niemeier, Simone Tilmes, and Harri Kokkola
Earth Syst. Dynam., 15, 405–427, https://doi.org/10.5194/esd-15-405-2024, https://doi.org/10.5194/esd-15-405-2024, 2024
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This study is the second in a two-part series in which we explore the dependency of the impacts of stratospheric sulfur injections on both the model employed and the strategy of injection utilized. The study uncovers uncertainties associated with these techniques to cool climate, highlighting how the simulated climate impacts are dependent on both the selected model and the magnitude of the injections. We also show that estimating precipitation impacts of aerosol injection is a complex task.
Shaoyue Qiu, Xue Zheng, David Painemal, Christopher R. Terai, and Xiaoli Zhou
Atmos. Chem. Phys., 24, 2913–2935, https://doi.org/10.5194/acp-24-2913-2024, https://doi.org/10.5194/acp-24-2913-2024, 2024
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The aerosol indirect effect (AIE) depends on cloud states, which exhibit significant diurnal variations in the northeastern Atlantic. Yet the AIE diurnal cycle remains poorly understood. Using satellite retrievals, we find a pronounced “U-shaped” diurnal variation in the AIE, which is contributed to by the transition of cloud states combined with the lagged cloud responses. This suggests that polar-orbiting satellites with overpass times at noon underestimate daytime mean values of the AIE.
Dominic Heslin-Rees, Peter Tunved, Johan Ström, Roxana Cremer, Paul Zieger, Ilona Riipinen, Annica M. L. Ekman, Konstantinos Eleftheriadis, and Radovan Krejci
Atmos. Chem. Phys., 24, 2059–2075, https://doi.org/10.5194/acp-24-2059-2024, https://doi.org/10.5194/acp-24-2059-2024, 2024
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Light-absorbing atmospheric particles (e.g. black carbon – BC) exert a warming effect on the Arctic climate. We show that the amount of particle light absorption decreased from 2002 to 2023. We conclude that in addition to reductions in emissions of BC, wet removal plays a role in the long-term reduction of BC in the Arctic, given the increase in surface precipitation experienced by air masses arriving at the site. The potential impact of biomass burning events is shown to have increased.
Kalle Nordling, Jukka-Pekka Keskinen, Sami Romakkaniemi, Harri Kokkola, Petri Räisänen, Antti Lipponen, Antti-Ilari Partanen, Jaakko Ahola, Juha Tonttila, Muzaffer Ege Alper, Hannele Korhonen, and Tomi Raatikainen
Atmos. Chem. Phys., 24, 869–890, https://doi.org/10.5194/acp-24-869-2024, https://doi.org/10.5194/acp-24-869-2024, 2024
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Our results show that the global model is stable and it provides meaningful results. This way we can include a physics-based presentation of sub-grid physics (physics which happens on a 100 m scale) in the global model, whose resolution is on a 100 km scale.
Karl-Göran Karlsson, Martin Stengel, Jan Fokke Meirink, Aku Riihelä, Jörg Trentmann, Tom Akkermans, Diana Stein, Abhay Devasthale, Salomon Eliasson, Erik Johansson, Nina Håkansson, Irina Solodovnik, Nikos Benas, Nicolas Clerbaux, Nathalie Selbach, Marc Schröder, and Rainer Hollmann
Earth Syst. Sci. Data, 15, 4901–4926, https://doi.org/10.5194/essd-15-4901-2023, https://doi.org/10.5194/essd-15-4901-2023, 2023
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This paper presents a global climate data record on cloud parameters, radiation at the surface and at the top of atmosphere, and surface albedo. The temporal coverage is 1979–2020 (42 years) and the data record is also continuously updated until present time. Thus, more than four decades of climate parameters are provided. Based on CLARA-A3, studies on distribution of clouds and radiation parameters can be made and, especially, investigations of climate trends and evaluation of climate models.
Hannah C. Frostenberg, André Welti, Mikael Luhr, Julien Savre, Erik S. Thomson, and Luisa Ickes
Atmos. Chem. Phys., 23, 10883–10900, https://doi.org/10.5194/acp-23-10883-2023, https://doi.org/10.5194/acp-23-10883-2023, 2023
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Observations show that ice-nucleating particle concentrations (INPCs) have a large variety and follow lognormal distributions for a given temperature. We introduce a new immersion freezing parameterization that applies this lognormal behavior. INPCs are drawn randomly from a temperature-dependent lognormal distribution. We then show that the ice content of the modeled Arctic stratocumulus cloud is highly sensitive to the probability of drawing large INPCs.
Simon Kirschler, Christiane Voigt, Bruce E. Anderson, Gao Chen, Ewan C. Crosbie, Richard A. Ferrare, Valerian Hahn, Johnathan W. Hair, Stefan Kaufmann, Richard H. Moore, David Painemal, Claire E. Robinson, Kevin J. Sanchez, Amy J. Scarino, Taylor J. Shingler, Michael A. Shook, Kenneth L. Thornhill, Edward L. Winstead, Luke D. Ziemba, and Armin Sorooshian
Atmos. Chem. Phys., 23, 10731–10750, https://doi.org/10.5194/acp-23-10731-2023, https://doi.org/10.5194/acp-23-10731-2023, 2023
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In this study we present an overview of liquid and mixed-phase clouds and precipitation in the marine boundary layer over the western North Atlantic Ocean. We compare microphysical properties of pure liquid clouds to mixed-phase clouds and show that the initiation of the ice phase in mixed-phase clouds promotes precipitation. The observational data presented in this study are well suited for investigating the processes that give rise to liquid and mixed-phase clouds, ice, and precipitation.
Sushant Das, Frida Bender, and Thorsten Mauritsen
EGUsphere, https://doi.org/10.5194/egusphere-2023-1605, https://doi.org/10.5194/egusphere-2023-1605, 2023
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Quantifying global and Indian precipitation responses to anthropogenic aerosol and CO2 forcings using multiple models is needed for reducing climate uncertainty. The response to global warming from CO2 increases precipitation both globally and over India, whereas the cooling response to sulfate aerosol leads to a reduction in precipitation in both cases. An opposite response to black carbon is noted i.e., a global decrease but an increase of precipitation over India implying changes in dynamics.
Armin Sorooshian, Mikhail D. Alexandrov, Adam D. Bell, Ryan Bennett, Grace Betito, Sharon P. Burton, Megan E. Buzanowicz, Brian Cairns, Eduard V. Chemyakin, Gao Chen, Yonghoon Choi, Brian L. Collister, Anthony L. Cook, Andrea F. Corral, Ewan C. Crosbie, Bastiaan van Diedenhoven, Joshua P. DiGangi, Glenn S. Diskin, Sanja Dmitrovic, Eva-Lou Edwards, Marta A. Fenn, Richard A. Ferrare, David van Gilst, Johnathan W. Hair, David B. Harper, Miguel Ricardo A. Hilario, Chris A. Hostetler, Nathan Jester, Michael Jones, Simon Kirschler, Mary M. Kleb, John M. Kusterer, Sean Leavor, Joseph W. Lee, Hongyu Liu, Kayla McCauley, Richard H. Moore, Joseph Nied, Anthony Notari, John B. Nowak, David Painemal, Kasey E. Phillips, Claire E. Robinson, Amy Jo Scarino, Joseph S. Schlosser, Shane T. Seaman, Chellappan Seethala, Taylor J. Shingler, Michael A. Shook, Kenneth A. Sinclair, William L. Smith Jr., Douglas A. Spangenberg, Snorre A. Stamnes, Kenneth L. Thornhill, Christiane Voigt, Holger Vömel, Andrzej P. Wasilewski, Hailong Wang, Edward L. Winstead, Kira Zeider, Xubin Zeng, Bo Zhang, Luke D. Ziemba, and Paquita Zuidema
Earth Syst. Sci. Data, 15, 3419–3472, https://doi.org/10.5194/essd-15-3419-2023, https://doi.org/10.5194/essd-15-3419-2023, 2023
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The NASA Aerosol Cloud meTeorology Interactions oVer the western ATlantic Experiment (ACTIVATE) produced a unique dataset for research into aerosol–cloud–meteorology interactions. HU-25 Falcon and King Air aircraft conducted systematic and spatially coordinated flights over the northwest Atlantic Ocean. This paper describes the ACTIVATE flight strategy, instrument and complementary dataset products, data access and usage details, and data application notes.
Michael S. Diamond
Atmos. Chem. Phys., 23, 8259–8269, https://doi.org/10.5194/acp-23-8259-2023, https://doi.org/10.5194/acp-23-8259-2023, 2023
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Fuel sulfur regulations were implemented for ships in 2020 to improve air quality but may also accelerate global warming. We use spatial statistics and satellite retrievals to detect changes in the size of cloud droplets and find evidence for a resulting decrease in cloud brightness within a major shipping corridor after the sulfur limits went into effect. Our results confirm both that the regulations are being followed and that they are having a warming influence via their effect on clouds.
Ines Bulatovic, Julien Savre, Michael Tjernström, Caroline Leck, and Annica M. L. Ekman
Atmos. Chem. Phys., 23, 7033–7055, https://doi.org/10.5194/acp-23-7033-2023, https://doi.org/10.5194/acp-23-7033-2023, 2023
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We use numerical modeling with detailed cloud microphysics to investigate a low-altitude cloud system consisting of two cloud layers – a type of cloud situation which was commonly observed during the summer of 2018 in the central Arctic (north of 80° N). The model generally reproduces the observed cloud layers and the thermodynamic structure of the lower atmosphere well. The cloud system is maintained unless there are low aerosol number concentrations or high large-scale wind speeds.
Ian Chang, Lan Gao, Connor J. Flynn, Yohei Shinozuka, Sarah J. Doherty, Michael S. Diamond, Karla M. Longo, Gonzalo A. Ferrada, Gregory R. Carmichael, Patricia Castellanos, Arlindo M. da Silva, Pablo E. Saide, Calvin Howes, Zhixin Xue, Marc Mallet, Ravi Govindaraju, Qiaoqiao Wang, Yafang Cheng, Yan Feng, Sharon P. Burton, Richard A. Ferrare, Samuel E. LeBlanc, Meloë S. Kacenelenbogen, Kristina Pistone, Michal Segal-Rozenhaimer, Kerry G. Meyer, Ju-Mee Ryoo, Leonhard Pfister, Adeyemi A. Adebiyi, Robert Wood, Paquita Zuidema, Sundar A. Christopher, and Jens Redemann
Atmos. Chem. Phys., 23, 4283–4309, https://doi.org/10.5194/acp-23-4283-2023, https://doi.org/10.5194/acp-23-4283-2023, 2023
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Abundant aerosols are present above low-level liquid clouds over the southeastern Atlantic during late austral spring. The model simulation differences in the proportion of aerosol residing in the planetary boundary layer and in the free troposphere can greatly affect the regional aerosol radiative effects. This study examines the aerosol loading and fractional aerosol loading in the free troposphere among various models and evaluates them against measurements from the NASA ORACLES campaign.
Aiden R. Jönsson and Frida A.-M. Bender
Earth Syst. Dynam., 14, 345–365, https://doi.org/10.5194/esd-14-345-2023, https://doi.org/10.5194/esd-14-345-2023, 2023
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The Earth has nearly the same mean albedo in both hemispheres, a feature not well replicated by climate models. Global warming causes changes in surface and cloud properties that affect albedo and that feed back into the warming. We show that models predict more darkening due to ice loss in the Northern than in the Southern Hemisphere in response to increasing CO2 concentrations. This is, to varying degrees, counteracted by changes in cloud cover, with implications for cloud feedback on climate.
Tuuli Miinalainen, Harri Kokkola, Antti Lipponen, Antti-Pekka Hyvärinen, Vijay Kumar Soni, Kari E. J. Lehtinen, and Thomas Kühn
Atmos. Chem. Phys., 23, 3471–3491, https://doi.org/10.5194/acp-23-3471-2023, https://doi.org/10.5194/acp-23-3471-2023, 2023
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We simulated the effects of aerosol emission mitigation on both global and regional radiative forcing and city-level air quality with a global-scale climate model. We used a machine learning downscaling approach to bias-correct the PM2.5 values obtained from the global model for the Indian megacity New Delhi. Our results indicate that aerosol mitigation could result in both improved air quality and less radiative heating for India.
Peter Kuma, Frida A.-M. Bender, Alex Schuddeboom, Adrian J. McDonald, and Øyvind Seland
Atmos. Chem. Phys., 23, 523–549, https://doi.org/10.5194/acp-23-523-2023, https://doi.org/10.5194/acp-23-523-2023, 2023
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We present a machine learning method for determining cloud types in climate model output and satellite observations based on ground observations of cloud genera. We analyse cloud type biases and changes with temperature in climate models and show that the bias is anticorrelated with climate sensitivity. Models simulating decreasing stratiform and increasing cumuliform clouds with increased CO2 concentration tend to have higher climate sensitivity than models simulating the opposite tendencies.
Ville Leinonen, Harri Kokkola, Taina Yli-Juuti, Tero Mielonen, Thomas Kühn, Tuomo Nieminen, Simo Heikkinen, Tuuli Miinalainen, Tommi Bergman, Ken Carslaw, Stefano Decesari, Markus Fiebig, Tareq Hussein, Niku Kivekäs, Radovan Krejci, Markku Kulmala, Ari Leskinen, Andreas Massling, Nikos Mihalopoulos, Jane P. Mulcahy, Steffen M. Noe, Twan van Noije, Fiona M. O'Connor, Colin O'Dowd, Dirk Olivie, Jakob B. Pernov, Tuukka Petäjä, Øyvind Seland, Michael Schulz, Catherine E. Scott, Henrik Skov, Erik Swietlicki, Thomas Tuch, Alfred Wiedensohler, Annele Virtanen, and Santtu Mikkonen
Atmos. Chem. Phys., 22, 12873–12905, https://doi.org/10.5194/acp-22-12873-2022, https://doi.org/10.5194/acp-22-12873-2022, 2022
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We provide the first extensive comparison of detailed aerosol size distribution trends between in situ observations from Europe and five different earth system models. We investigated aerosol modes (nucleation, Aitken, and accumulation) separately and were able to show the differences between measured and modeled trends and especially their seasonal patterns. The differences in model results are likely due to complex effects of several processes instead of certain specific model features.
Silvia M. Calderón, Juha Tonttila, Angela Buchholz, Jorma Joutsensaari, Mika Komppula, Ari Leskinen, Liqing Hao, Dmitri Moisseev, Iida Pullinen, Petri Tiitta, Jian Xu, Annele Virtanen, Harri Kokkola, and Sami Romakkaniemi
Atmos. Chem. Phys., 22, 12417–12441, https://doi.org/10.5194/acp-22-12417-2022, https://doi.org/10.5194/acp-22-12417-2022, 2022
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The spatial and temporal restrictions of observations and oversimplified aerosol representation in large eddy simulations (LES) limit our understanding of aerosol–stratocumulus interactions. In this closure study of in situ and remote sensing observations and outputs from UCLALES–SALSA, we have assessed the role of convective overturning and aerosol effects in two cloud events observed at the Puijo SMEAR IV station, Finland, a diurnal-high aerosol case and a nocturnal-low aerosol case.
Michael S. Diamond, Pablo E. Saide, Paquita Zuidema, Andrew S. Ackerman, Sarah J. Doherty, Ann M. Fridlind, Hamish Gordon, Calvin Howes, Jan Kazil, Takanobu Yamaguchi, Jianhao Zhang, Graham Feingold, and Robert Wood
Atmos. Chem. Phys., 22, 12113–12151, https://doi.org/10.5194/acp-22-12113-2022, https://doi.org/10.5194/acp-22-12113-2022, 2022
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Smoke from southern Africa blankets the southeast Atlantic from June-October, overlying a major transition region between overcast and scattered clouds. The smoke affects Earth's radiation budget by absorbing sunlight and changing cloud properties. We investigate these effects in regional climate and large eddy simulation models based on international field campaigns. We find that large-scale circulation changes more strongly affect cloud transitions than smoke microphysical effects in our case.
Sini Isokääntä, Paul Kim, Santtu Mikkonen, Thomas Kühn, Harri Kokkola, Taina Yli-Juuti, Liine Heikkinen, Krista Luoma, Tuukka Petäjä, Zak Kipling, Daniel Partridge, and Annele Virtanen
Atmos. Chem. Phys., 22, 11823–11843, https://doi.org/10.5194/acp-22-11823-2022, https://doi.org/10.5194/acp-22-11823-2022, 2022
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This research employs air mass history analysis and observations to study how clouds and precipitation affect atmospheric aerosols during transport to a boreal forest site. The mass concentrations of studied chemical species showed exponential decrease as a function of accumulated rain along the air mass route. Our analysis revealed in-cloud sulfate formation, while no major changes in organic mass were seen. Most of the in-cloud-formed sulfate could be assigned to particle sizes above 200 nm.
Qirui Zhong, Nick Schutgens, Guido van der Werf, Twan van Noije, Kostas Tsigaridis, Susanne E. Bauer, Tero Mielonen, Alf Kirkevåg, Øyvind Seland, Harri Kokkola, Ramiro Checa-Garcia, David Neubauer, Zak Kipling, Hitoshi Matsui, Paul Ginoux, Toshihiko Takemura, Philippe Le Sager, Samuel Rémy, Huisheng Bian, Mian Chin, Kai Zhang, Jialei Zhu, Svetlana G. Tsyro, Gabriele Curci, Anna Protonotariou, Ben Johnson, Joyce E. Penner, Nicolas Bellouin, Ragnhild B. Skeie, and Gunnar Myhre
Atmos. Chem. Phys., 22, 11009–11032, https://doi.org/10.5194/acp-22-11009-2022, https://doi.org/10.5194/acp-22-11009-2022, 2022
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Aerosol optical depth (AOD) errors for biomass burning aerosol (BBA) are evaluated in 18 global models against satellite datasets. Notwithstanding biases in satellite products, they allow model evaluations. We observe large and diverse model biases due to errors in BBA. Further interpretations of AOD diversities suggest large biases exist in key processes for BBA which require better constraining. These results can contribute to further model improvement and development.
Marje Prank, Juha Tonttila, Jaakko Ahola, Harri Kokkola, Thomas Kühn, Sami Romakkaniemi, and Tomi Raatikainen
Atmos. Chem. Phys., 22, 10971–10992, https://doi.org/10.5194/acp-22-10971-2022, https://doi.org/10.5194/acp-22-10971-2022, 2022
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Aerosols and clouds persist as the dominant sources of uncertainty in climate projections. In this modelling study, we investigate the role of marine aerosols in influencing the lifetime of low-level clouds. Our high resolution simulations show that sea spray can both extend and shorten the lifetime of the cloud layer depending on the model setup. The impact of the primary marine organics is relatively limited while secondary aerosol from monoterpenes can have larger impact.
Edward Gryspeerdt, Daniel T. McCoy, Ewan Crosbie, Richard H. Moore, Graeme J. Nott, David Painemal, Jennifer Small-Griswold, Armin Sorooshian, and Luke Ziemba
Atmos. Meas. Tech., 15, 3875–3892, https://doi.org/10.5194/amt-15-3875-2022, https://doi.org/10.5194/amt-15-3875-2022, 2022
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Droplet number concentration is a key property of clouds, influencing a variety of cloud processes. It is also used for estimating the cloud response to aerosols. The satellite retrieval depends on a number of assumptions – different sampling strategies are used to select cases where these assumptions are most likely to hold. Here we investigate the impact of these strategies on the agreement with in situ data, the droplet number climatology and estimates of the indirect radiative forcing.
Cheng You, Michael Tjernström, and Abhay Devasthale
Atmos. Chem. Phys., 22, 8037–8057, https://doi.org/10.5194/acp-22-8037-2022, https://doi.org/10.5194/acp-22-8037-2022, 2022
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In winter when solar radiation is absent in the Arctic, the poleward transport of heat and moisture into the high Arctic becomes the main contribution of Arctic warming. Over completely frozen ocean sectors, total surface energy budget is dominated by net long-wave heat, while over the Barents Sea, with an open ocean to the south, total net surface energy budget is dominated by the surface turbulent heat.
Zhujun Li, David Painemal, Gregory Schuster, Marian Clayton, Richard Ferrare, Mark Vaughan, Damien Josset, Jayanta Kar, and Charles Trepte
Atmos. Meas. Tech., 15, 2745–2766, https://doi.org/10.5194/amt-15-2745-2022, https://doi.org/10.5194/amt-15-2745-2022, 2022
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For more than 15 years, CALIPSO has revolutionized our understanding of the role of aerosols in climate. Here we evaluate CALIPSO aerosol typing over the ocean using an independent CALIPSO–CloudSat product. The analysis suggests that CALIPSO correctly categorizes clean marine aerosol over the open ocean, elevated smoke over the SE Atlantic, and dust over the tropical Atlantic. Similarities between clean and dusty marine over the open ocean implies that algorithm modifications are warranted.
Jaakko Ahola, Tomi Raatikainen, Muzaffer Ege Alper, Jukka-Pekka Keskinen, Harri Kokkola, Antti Kukkurainen, Antti Lipponen, Jia Liu, Kalle Nordling, Antti-Ilari Partanen, Sami Romakkaniemi, Petri Räisänen, Juha Tonttila, and Hannele Korhonen
Atmos. Chem. Phys., 22, 4523–4537, https://doi.org/10.5194/acp-22-4523-2022, https://doi.org/10.5194/acp-22-4523-2022, 2022
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Clouds are important for the climate, and cloud droplets have a significant role in cloud properties. Cloud droplets form when air rises and cools and water vapour condenses on small particles that can be natural or of anthropogenic origin. Currently, the updraft velocity, meaning how fast the air rises, is poorly represented in global climate models. In our study, we show three methods that will improve the depiction of updraft velocity and which properties are vital to updrafts.
Tomi Raatikainen, Marje Prank, Jaakko Ahola, Harri Kokkola, Juha Tonttila, and Sami Romakkaniemi
Atmos. Chem. Phys., 22, 3763–3778, https://doi.org/10.5194/acp-22-3763-2022, https://doi.org/10.5194/acp-22-3763-2022, 2022
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Mineral dust or similar ice-nucleating particles (INPs) are needed to initiate cloud droplet freezing at temperatures common in shallow clouds. In this work we examine how INPs that are released from the sea surface impact marine clouds. Our high-resolution simulations show that turbulent updraughts carry these particles effectively up to the clouds, where they initiate cloud droplet freezing. Sea surface INP emissions become more important with decreasing background dust INP concentrations.
Jessica Slater, Hugh Coe, Gordon McFiggans, Juha Tonttila, and Sami Romakkaniemi
Atmos. Chem. Phys., 22, 2937–2953, https://doi.org/10.5194/acp-22-2937-2022, https://doi.org/10.5194/acp-22-2937-2022, 2022
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This paper shows the specific impact of black carbon (BC) on the aerosol–planetary boundary layer (PBL) feedback and its influence on a Beijing haze episode. Overall, this paper shows that strong temperature inversions prevent BC heating within the PBL from significantly increasing PBL height, while BC above the PBL suppresses PBL development significantly through the day. From this we suggest a method by which both locally and regionally emitted BC may impact urban pollution episodes.
Matthew W. Christensen, Andrew Gettelman, Jan Cermak, Guy Dagan, Michael Diamond, Alyson Douglas, Graham Feingold, Franziska Glassmeier, Tom Goren, Daniel P. Grosvenor, Edward Gryspeerdt, Ralph Kahn, Zhanqing Li, Po-Lun Ma, Florent Malavelle, Isabel L. McCoy, Daniel T. McCoy, Greg McFarquhar, Johannes Mülmenstädt, Sandip Pal, Anna Possner, Adam Povey, Johannes Quaas, Daniel Rosenfeld, Anja Schmidt, Roland Schrödner, Armin Sorooshian, Philip Stier, Velle Toll, Duncan Watson-Parris, Robert Wood, Mingxi Yang, and Tianle Yuan
Atmos. Chem. Phys., 22, 641–674, https://doi.org/10.5194/acp-22-641-2022, https://doi.org/10.5194/acp-22-641-2022, 2022
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Trace gases and aerosols (tiny airborne particles) are released from a variety of point sources around the globe. Examples include volcanoes, industrial chimneys, forest fires, and ship stacks. These sources provide opportunistic experiments with which to quantify the role of aerosols in modifying cloud properties. We review the current state of understanding on the influence of aerosol on climate built from the wide range of natural and anthropogenic laboratories investigated in recent decades.
Anton Laakso, Ulrike Niemeier, Daniele Visioni, Simone Tilmes, and Harri Kokkola
Atmos. Chem. Phys., 22, 93–118, https://doi.org/10.5194/acp-22-93-2022, https://doi.org/10.5194/acp-22-93-2022, 2022
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The use of different spatio-temporal sulfur injection strategies with different magnitudes to create an artificial reflective aerosol layer to cool the climate is studied using sectional and modal aerosol schemes in a climate model. There are significant differences in the results depending on the aerosol microphysical module used. Different spatio-temporal injection strategies have a significant impact on the magnitude and zonal distribution of radiative forcing and atmospheric dynamics.
Manu Anna Thomas, Abhay Devasthale, and Michael Kahnert
Atmos. Chem. Phys., 22, 119–137, https://doi.org/10.5194/acp-22-119-2022, https://doi.org/10.5194/acp-22-119-2022, 2022
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The Southern Ocean (SO) covers a large area of our planet and its boundary layer is dominated by sea salt aerosols during winter. These aerosols have large implications for the regional climate through their direct and indirect effects. Using satellite and reanalysis data, we document if and how the aerosol properties over the SO are dependent on different local meteorological parameters. Such an observational assessment is necessary to improve the understanding of atmospheric aerosol processes.
Sarah J. Doherty, Pablo E. Saide, Paquita Zuidema, Yohei Shinozuka, Gonzalo A. Ferrada, Hamish Gordon, Marc Mallet, Kerry Meyer, David Painemal, Steven G. Howell, Steffen Freitag, Amie Dobracki, James R. Podolske, Sharon P. Burton, Richard A. Ferrare, Calvin Howes, Pierre Nabat, Gregory R. Carmichael, Arlindo da Silva, Kristina Pistone, Ian Chang, Lan Gao, Robert Wood, and Jens Redemann
Atmos. Chem. Phys., 22, 1–46, https://doi.org/10.5194/acp-22-1-2022, https://doi.org/10.5194/acp-22-1-2022, 2022
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Between July and October, biomass burning smoke is advected over the southeastern Atlantic Ocean, leading to climate forcing. Model calculations of forcing by this plume vary significantly in both magnitude and sign. This paper compares aerosol and cloud properties observed during three NASA ORACLES field campaigns to the same in four models. It quantifies modeled biases in properties key to aerosol direct radiative forcing and evaluates how these biases propagate to biases in forcing.
Manu Anna Thomas, Abhay Devasthale, and Tiina Nygård
Atmos. Chem. Phys., 21, 16593–16608, https://doi.org/10.5194/acp-21-16593-2021, https://doi.org/10.5194/acp-21-16593-2021, 2021
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The impact of transported pollutants and their spatial distribution in the Arctic are governed by the local atmospheric circulation or weather states. Therefore, we investigated eight different atmospheric circulation types observed during the spring season in the Arctic. Using satellite and reanalysis datasets, this study provides a comprehensive assessment of the typical circulation patterns that can lead to enhanced or reduced pollution concentrations in the different sectors of the Arctic.
Maria Sand, Bjørn H. Samset, Gunnar Myhre, Jonas Gliß, Susanne E. Bauer, Huisheng Bian, Mian Chin, Ramiro Checa-Garcia, Paul Ginoux, Zak Kipling, Alf Kirkevåg, Harri Kokkola, Philippe Le Sager, Marianne T. Lund, Hitoshi Matsui, Twan van Noije, Dirk J. L. Olivié, Samuel Remy, Michael Schulz, Philip Stier, Camilla W. Stjern, Toshihiko Takemura, Kostas Tsigaridis, Svetlana G. Tsyro, and Duncan Watson-Parris
Atmos. Chem. Phys., 21, 15929–15947, https://doi.org/10.5194/acp-21-15929-2021, https://doi.org/10.5194/acp-21-15929-2021, 2021
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Absorption of shortwave radiation by aerosols can modify precipitation and clouds but is poorly constrained in models. A total of 15 different aerosol models from AeroCom phase III have reported total aerosol absorption, and for the first time, 11 of these models have reported in a consistent experiment the contributions to absorption from black carbon, dust, and organic aerosol. Here, we document the model diversity in aerosol absorption.
David Painemal, Douglas Spangenberg, William L. Smith Jr., Patrick Minnis, Brian Cairns, Richard H. Moore, Ewan Crosbie, Claire Robinson, Kenneth L. Thornhill, Edward L. Winstead, and Luke Ziemba
Atmos. Meas. Tech., 14, 6633–6646, https://doi.org/10.5194/amt-14-6633-2021, https://doi.org/10.5194/amt-14-6633-2021, 2021
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Cloud properties derived from satellite sensors are critical for the global monitoring of climate. This study evaluates satellite-based cloud properties over the North Atlantic using airborne data collected during NAAMES. Satellite observations of droplet size and cloud optical depth tend to compare well with NAAMES data. The analysis indicates that the satellite pixel resolution and the specific viewing geometry need to be taken into account in research applications.
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Short summary
We use a numerical model to study interactions between humid light-absorbing aerosol plumes, clouds, and radiation over the southeast Atlantic. We find that the warming produced by the aerosols reduces cloud cover, especially in highly polluted situations. Aerosol impacts on drizzle play a minor role. However, aerosol effects on cloud reflectivity and moisture-induced changes in cloud cover dominate the climatic response and lead to an overall cooling by the biomass burning plumes.
We use a numerical model to study interactions between humid light-absorbing aerosol plumes,...
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