Articles | Volume 26, issue 20
https://doi.org/10.5194/acp-26-14577-2026
© Author(s) 2026. 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-26-14577-2026
© Author(s) 2026. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
15 Oct 2026
Research article |
| 15 Oct 2026
| 15 Oct 2026
Interacting effects of droplet number and ice formation processes on mixed-phase cold-air outbreak clouds
Institute for Climate and Atmospheric Science, School of Earth and Environment, University of Leeds, Leeds LS2 9JT, UK
Paul R. Field
Institute for Climate and Atmospheric Science, School of Earth and Environment, University of Leeds, Leeds LS2 9JT, UK
Met Office, Exeter EX1 3PB, UK
Ross J. Herbert
Institute for Climate and Atmospheric Science, School of Earth and Environment, University of Leeds, Leeds LS2 9JT, UK
Benjamin J. Murray
Institute for Climate and Atmospheric Science, School of Earth and Environment, University of Leeds, Leeds LS2 9JT, UK
Floortje van den Heuvel
British Antarctic Survey, Cambridge CB3 0ET, UK
Daniel P. Grosvenor
Institute for Climate and Atmospheric Science, School of Earth and Environment, University of Leeds, Leeds LS2 9JT, UK
Met Office, Exeter EX1 3PB, UK
Rachel W. N. Sansom
Institute for Climate and Atmospheric Science, School of Earth and Environment, University of Leeds, Leeds LS2 9JT, UK
Kenneth S. Carslaw
Institute for Climate and Atmospheric Science, School of Earth and Environment, University of Leeds, Leeds LS2 9JT, UK
Related authors
Xinyi Huang, Paul R. Field, Benjamin J. Murray, Daniel P. Grosvenor, Floortje van den Heuvel, and Kenneth S. Carslaw
Atmos. Chem. Phys., 25, 11363–11406, https://doi.org/10.5194/acp-25-11363-2025, https://doi.org/10.5194/acp-25-11363-2025, 2025
Short summary
Short summary
Cold-air outbreak (CAO) clouds play a vital role in climate prediction. This study explores the responses of CAO clouds to aerosols and ice production under different environmental conditions. We found that CAO cloud responses vary with cloud temperature and are strongly controlled by the liquid–ice partitioning in these clouds, suggesting the importance of good representations of cloud microphysics properties to predict the behaviours of CAO clouds in a warming climate.
Michael Biggart, Thomas W. Choularton, Martin W. Gallagher, Keith N. Bower, Gary Lloyd, Paul J. Connolly, Benjamin J. Murray, Mark D. Tarn, Erin N. Raif, and Steven J. Abel
Atmos. Chem. Phys., 26, 13401–13439, https://doi.org/10.5194/acp-26-13401-2026, https://doi.org/10.5194/acp-26-13401-2026, 2026
Short summary
Short summary
Microphysical processes controlling the phase of mixed-phase clouds in cold air outbreaks (CAOs) are poorly represented by climate models. Of these, secondary ice production (SIP) is a major contributor to uncertainties in the mixed-phase cloud response to warming. We examine observations made in CAOs to understand which SIP processes are dominating and under which conditions. Our results inform future modelling, helping reduce radiative flux biases and uncertainties in climate sensitivity.
Ross J. Herbert, Larissa Lacher, Alexander Böhmländer, Mark D. Tarn, Antoine Canzi, Aidan Pantoya, Evelyn Freney, Kristina Höhler, Pia Bogert, Céline Planche, Ping Tian, Michael Adams, Sarah Barr, David Brus, Nicole Büttner, Martin Daily, Konstantinos Doulgeris, Konstantinos Eleftheriadis, Grant Forster, Romy Fösig, Dimitrios G. Georgakopoulos, Maria I. Gini, A. Gannet Hallar, Radovan Krejci, Elke Ludewig, Mauro Mazzola, Ian B. McCubbin, Athanasios Nenes, Tuukka Petäjä, Joseph Robinson, Franziska Vogel, Paul Zieger, Stephen Arnold, Kenneth S. Carslaw, Naruki Hiranuma, Ottmar Möhler, and Benjamin J. Murray
Earth Syst. Sci. Data, 18, 6465–6483, https://doi.org/10.5194/essd-18-6465-2026, https://doi.org/10.5194/essd-18-6465-2026, 2026
Short summary
Short summary
Ice formation in sub-zero clouds is influenced by airborne particles called ice-nucleating particles (INPs), whose concentrations vary substantially over short time and spatial scales. To assess the role of INPs in our climate, a comprehensive and consistent global dataset is essential. Our GloPINE model-ready dataset is a major step in this direction, comprising 36,000 measurements made using a single instrument design (PINE) over 70,000 hours of operation at 20 Northern Hemisphere sites.
Joseph Robinson, Martin I. Daily, Polly B. Foster, Jack P. Macklin, James B. McQuaid, Mark D. Tarn, and Benjamin J. Murray
Aerosol Research, 4, 373–396, https://doi.org/10.5194/ar-4-373-2026, https://doi.org/10.5194/ar-4-373-2026, 2026
Short summary
Short summary
Ice formation in many clouds is initiated by airborne particles, which are often measured by collecting them on a filter and washing them into water for analysis. Using controlled laboratory experiments, we show that some of these particles adhere strongly to the filter and are not recovered. As a result, this common method can underestimate how many ice-forming particles are present in the atmosphere.
Megan Malpas, Floortje van den Heuvel, Rachael H. Rhodes, Xin Yang, Shaun Miller, Manuela van Pinxteren, Sebastian Zeppenfeld, and Markus M. Frey
EGUsphere, https://doi.org/10.5194/egusphere-2026-5047, https://doi.org/10.5194/egusphere-2026-5047, 2026
Short summary
Short summary
We investigated a type of aerosol that facilitates the formation of ice in clouds, to understand whether snow on sea ice lifted by strong winds in the Arctic could be a source of this aerosol. We did not observe increases in the concentration of this aerosol during these strong wind events; however, we did observe the formation of ice on aerosol at warmer temperatures. We conclude that aerosol released during strong winds is influenced by both snow sublimation and transport from lower latitudes.
Ulrike Proske, John Hillier, Stefan Gaillard, Theresa Blume, Eduardo Queiroz Alves, Susanne Buiter, Ken S. Carslaw, Kirsten von Elverfeldt, Tim H. M. van Emmerik, Barbara Ervens, Rolf Hut, Sam Illingworth, Daniel Klotz, and Jonas Pyschik
Geosci. Commun., 9, 371–383, https://doi.org/10.5194/gc-9-371-2026, https://doi.org/10.5194/gc-9-371-2026, 2026
Short summary
Short summary
We explain a new article type that is being introduced in participating EGU publications. "LESSONS" articles describe the Limitations, Errors, Surprises, Shortcomings and Opportunities for New Science emerging from the scientific process. The publication of non-positive results and associated learnings aims to complete an unbiased record of the research effort, contributes to open and transparent science, allows the authors and others to learn, and may open opportunities for new science.
Noah Liguori-Bills, Catherine E. Scott, Ken S. Carslaw, Natalie Kehrwald, Stijn Hantson, Susan Kaspari, Carlo Barbante, Elena Barbaro, Paolo Gabrielli, Roberta Zangrando, Lonnie G. Thompson, and Douglas S. Hamilton
EGUsphere, https://doi.org/10.5194/egusphere-2026-2728, https://doi.org/10.5194/egusphere-2026-2728, 2026
Short summary
Short summary
Ice cores preserve changes in landscape fires and human-caused combustion. In this study, we compared ice core data from every continent, except Oceania, to computer model simulations of fire. We found a large disagreement in the 1850 CE to 1980 CE black carbon ratio. After exploring changes in emissions, transport, and aerosol microphysical processes as potential reasons for this disagreement, our results suggested that fire emission input datasets for climate models are the primary cause.
Nicole Büttner, Romy Fösig, Alexander Böhmländer, Larissa Lacher, Franziska Vogel, Mark Tarn, Pia Bogert, Jens Nadolny, Benjamin Murray, and Ottmar Möhler
Atmos. Meas. Tech., 19, 5007–5026, https://doi.org/10.5194/amt-19-5007-2026, https://doi.org/10.5194/amt-19-5007-2026, 2026
Short summary
Short summary
We developed a new Python software tool that standardises and automates the analysis of data from a cloud simulation chamber. It identifies ice-forming particles in the atmosphere and ensures consistent data quality through built-in checks, making results more comparable across studies. We also analysed measurement data to provide recommendations for improving instrument reliability and long-term monitoring of atmospheric ice-forming particles. This helps to better understand how clouds behave.
Gabriella Wallentin, Alexander Böhmländer, Ross Herbert, Heike Wex, Charlotte M. Beall, Pia Bogert, Zoé Brasseur, Jie Chen, Jessie M. Creamean, Paul J. DeMott, Oliver Eckermann, Kunfeng Gao, Xianda Gong, Silvia Henning, Naruki Hiranuma, Christina S. McCluskey, Christos Mitsios, Ottmar Möhler, Athanasios Nenes, Mark D. Tarn, Christian Tatzelt, Ping Tian, Yutaka Tobo, Franziska Vogel, André Welti, Elise Wilbourn, Jennifer Winstone, and Corinna Hoose
EGUsphere, https://doi.org/10.5194/egusphere-2026-4134, https://doi.org/10.5194/egusphere-2026-4134, 2026
This preprint is open for discussion and under review for Atmospheric Chemistry and Physics (ACP).
Short summary
Short summary
Ice nucleating particles (INPs) are aerosols essential for cloud ice formation in the temperature range -38 °C and 0 °C. Due to measurement challenges, the availability of observations of INPs remains scarce. This study applies machine learning to predict a global INP distribution using aerosol mass concentration reanalysis and observed INPs. This manuscript demonstrates that even with limited measurements, the occurrence of INPs can be estimated, following the spatial pattern of key aerosols.
Ezri E. Alkilani-Brown, Declan L. Finney, Alan M. Blyth, Paul R. Field, Jonathan Crosier, and Chetan R. Deva
EGUsphere, https://doi.org/10.5194/egusphere-2026-3385, https://doi.org/10.5194/egusphere-2026-3385, 2026
Short summary
Short summary
Graupel continues to be one of the most poorly characterised ice particles in deep convective clouds. In situ images are critical for understanding its microphysical development. Consequently, a plethora of independent classification schemes has become commonplace. Here, an independent evaluation of several open-source algorithms was undertaken to assess if they are generalisable. Classifications were then applied to the entire DCMEX campaign, to infer graupel concentrations.
Zhangcheng Pei, Sonya L. Fiddes, Marc D. Mallet, Matthew T. Woodhouse, Simon P. Alexander, Alain Protat, Kalli Furtado, and Paul R. Field
EGUsphere, https://doi.org/10.5194/egusphere-2026-3541, https://doi.org/10.5194/egusphere-2026-3541, 2026
This preprint is open for discussion and under review for Atmospheric Chemistry and Physics (ACP).
Short summary
Short summary
Climate models misrepresent Southern Ocean clouds, causing warming biases. Using ship data, we updated a weather model to test how sea spray affects cloud ice. Adding realistic ocean particles prevents deep clouds from freezing too fast, correcting sunlight trasmissions. Yet, shallow clouds remain flawed due to missing moisture. Thus, accurate climate predictions require improving both aerosol-cloud interactions and large-scale weather dynamics.
Kunal Ghosh, Leighton A. Regayre, Léa Prévost, and Ken S. Carslaw
EGUsphere, https://doi.org/10.5281/zenodo.20374157, https://doi.org/10.5281/zenodo.20374157, 2026
Short summary
Short summary
Tiny airborne particles affect climate by changing clouds, but this remains hard to predict. We tested whether an observed link between cloud droplet number and cloud water can reduce uncertainty in climate-model estimates. Using many versions of a climate model, we found that this link gives useful clues about cloud processes but cannot constrain aerosol–cloud climate effects on its own. Combining it with other observations helps, but also reveals weaknesses in how models represent clouds.
Xinyue Shao, Yaman Liu, Xinyi Dong, Minghuai Wang, Ruochong Xu, Joel A. Thornton, Duseong S. Jo, Man Yue, Wenxiang Shen, Manish Shrivastava, Stephen R. Arnold, and Ken S. Carslaw
Atmos. Chem. Phys., 26, 6427–6448, https://doi.org/10.5194/acp-26-6427-2026, https://doi.org/10.5194/acp-26-6427-2026, 2026
Short summary
Short summary
Highly Oxygenated Organic Molecules (HOMs) are key precursors of secondary organic aerosols (SOA). Incorporating the HOMs chemical mechanism into a global climate model allows for a reasonable reproduction of observed HOM characteristics. HOM-SOA constitutes a significant fraction of global SOA, and its distribution and formation pathways exhibit strong sensitivity to uncertainties in autoxidation processes and peroxy radical branching ratios.
Ken S. Carslaw, Leighton A. Regayre, Ulrike Proske, Andrew Gettelman, David M. H. Sexton, Yun Qian, Lauren R. Marshall, Oliver Wild, Marcus van Lier-Walqui, Annika Oertel, Saloua Peatier, Ben Yang, Jill S. Johnson, Sihan Li, Daniel T. McCoy, Benjamin M. Sanderson, Christina J. Williamson, Gregory S. Elsaesser, Kuniko Yamazaki, and Ben B. B. Booth
Atmos. Chem. Phys., 26, 4651–4667, https://doi.org/10.5194/acp-26-4651-2026, https://doi.org/10.5194/acp-26-4651-2026, 2026
Short summary
Short summary
A major challenge in climate science is reducing projection uncertainty despite advances in models and observational constraints. Perturbed parameter ensembles (PPEs) offer a powerful tool to explore and reduce uncertainty by revealing model weaknesses and guiding development. PPEs are now widely applied across climate systems and scales. We argue they should be prioritized alongside complexity and resolution in model resource planning.
Xinyue Shao, Minghuai Wang, Xinyi Dong, Yaman Liu, Stephen R. Arnold, Leighton A. Regayre, Duseong S. Jo, Wenxiang Shen, Hao Wang, Man Yue, Jingyi Wang, Wenxin Zhang, and Ken S. Carslaw
Atmos. Chem. Phys., 26, 4439–4451, https://doi.org/10.5194/acp-26-4439-2026, https://doi.org/10.5194/acp-26-4439-2026, 2026
Short summary
Short summary
This study uses a global chemistry–climate model to investigate how new particle formation (NPF) from highly oxygenated organic molecules (HOMs) contributes to cloud condensation nuclei (CCN) in both preindustrial and present-day environments and its impact on aerosol indirect radiative forcing. The findings highlight the crucial role of biogenic emissions in climate change, providing new insights for carbon-neutral scenarios and enhancing our understanding of aerosol–cloud interactions.
Masaru Yoshioka, Daniel P. Grosvenor, Amy H. Peace, Jim M. Haywood, Ying Chen, and Paul R. Field
Atmos. Chem. Phys., 26, 4341–4358, https://doi.org/10.5194/acp-26-4341-2026, https://doi.org/10.5194/acp-26-4341-2026, 2026
Short summary
Short summary
We used advanced computer simulations to study how aerosol particles from a volcanic eruption in Iceland affected clouds. The eruption plume increased small droplets, but changes in cloud water and horizontal extent were not clear. Satellite comparisons between plume and non-plume regions can miss volcanic effects due to spatial variability in weather and aerosol, but simulations can isolate the impact by comparing cases with and without the eruption.
Anna Tippett, Paul R. Field, and Edward Gryspeerdt
Atmos. Chem. Phys., 26, 4251–4274, https://doi.org/10.5194/acp-26-4251-2026, https://doi.org/10.5194/acp-26-4251-2026, 2026
Short summary
Short summary
Clouds and their interactions with tiny particles in the air (aerosols) are a large source of uncertainty in climate models. To study Marine Cloud Brightening (MCB), we use ship tracks (changes to clouds from ship pollution). Comparing real ship track data with model results, we find the model struggles under rainy conditions and overestimates effects at high pollution levels, suggesting it needs improvement for reliable MCB simulations.
Xu-Cheng He, Nathan Luke Abraham, Han Ding, Maria R. Russo, Daniel P. Grosvenor, Yao Ge, Xuemei Wang, Anthony C. Jones, Pedro Campuzano-Jost, Benjamin Nault, Agnieszka Kupc, Donald Blake, Jose L. Jimenez, Christina J. Williamson, James Weber, Alexander T. Archibald, and Hamish Gordon
Atmos. Chem. Phys., 26, 3805–3851, https://doi.org/10.5194/acp-26-3805-2026, https://doi.org/10.5194/acp-26-3805-2026, 2026
Short summary
Short summary
Aerosols affect clouds and climate. However, current climate models still struggle to simulate them accurately. We used aircraft data from a global mission to evaluate how well the UK Earth System Model represents aerosols and their precursors. Our results show that the model misses key formation processes in clean ocean regions, suggesting that future improvements should focus on better representing how aerosols form naturally in the atmosphere.
Léa M. C. Prévost, Leighton A. Regayre, Jill S. Johnson, Doug McNeall, Sean Milton, and Kenneth S. Carslaw
Atmos. Chem. Phys., 26, 2487–2530, https://doi.org/10.5194/acp-26-2487-2026, https://doi.org/10.5194/acp-26-2487-2026, 2026
Short summary
Short summary
Climate models rely on uncertain adjustable parameters. We tested millions of combinations of these inputs to see how well the model matches real-world data. We found that no single set of inputs can match several observations at the same time, which suggests that the issue lies in the model itself. We developed a method to detect these conflicts and trace them back trace them to their source. The aim is to help modellers target improvements that reduce uncertainty in climate projections.
Leighton A. Regayre, Léa M. C. Prévost, Kunal Ghosh, Jill S. Johnson, Jeremy E. Oakley, Jonathan Owen, Iain Webb, and Ken S. Carslaw
Atmos. Chem. Phys., 26, 2293–2317, https://doi.org/10.5194/acp-26-2293-2026, https://doi.org/10.5194/acp-26-2293-2026, 2026
Short summary
Short summary
Tiny particles called aerosols affect how much sunlight the Earth reflects back into space – one of the biggest climate uncertainties. We use a large set of climate model simulations and find that uncertainty drops in some regions, but persists in other areas, after comparing models to observations. By identifying the specific processes that cause the remaining uncertainty, we guide future efforts to reduce the aerosol forcing uncertainty so we can make more reliable climate predictions.
Rachel W. N. Sansom, Jill S. Johnson, Leighton A. Regayre, Lindsay A. Lee, and Ken S. Carslaw
Atmos. Chem. Phys., 26, 1713–1733, https://doi.org/10.5194/acp-26-1713-2026, https://doi.org/10.5194/acp-26-1713-2026, 2026
Short summary
Short summary
The cloud transition from stratocumulus to cumulus features a distinct decrease in cloud cover. We used a high-resolution model to simulate many instances of the transition with different environmental conditions. In low aerosol conditions, the transition occurred faster due to drizzle depleting the cloud of moisture and aerosol, whereas in high aerosol conditions, other factors were more important. Understanding different regimes is important for accurately simulating clouds in global models.
Mengyu Sun, Paul J. Connolly, Paul R. Field, Declan L. Finney, and Alan M. Blyth
Atmos. Chem. Phys., 25, 18549–18569, https://doi.org/10.5194/acp-25-18549-2025, https://doi.org/10.5194/acp-25-18549-2025, 2025
Short summary
Short summary
We investigated how extra ice particles form inside tropical storm clouds and how they affect rainfall and sunlight reflection. By using a weather model, we found that these extra ice particles can change how clouds grow, reduce heat escaping to space, and slightly shift where rain falls. This helps improve how weather and climate models predict tropical storms.
Mengyu Sun, Paul J. Connolly, Paul R. Field, Declan L. Finney, and Alan M. Blyth
EGUsphere, https://doi.org/10.5194/egusphere-2025-5665, https://doi.org/10.5194/egusphere-2025-5665, 2025
Short summary
Short summary
We use a high resolution weather model together with satellite and radar data to study how small particles in the air influence ice and rain in a tropical storm near Darwin. We find that when particle levels are moderate, storm clouds form more ice high in the atmosphere, spread a wider cloud cover, and produce stronger rainfall concentrated in certain regions. These results help improve how weather and climate models represent tropical storms and their rainfall.
Weiyu Zhang, Paul R. Field, Kwinten Van Weverberg, Piers M. Forster, Cyril J. Morcrette, and Alexandru Rap
Atmos. Chem. Phys., 25, 14153–14166, https://doi.org/10.5194/acp-25-14153-2025, https://doi.org/10.5194/acp-25-14153-2025, 2025
Short summary
Short summary
Contrail cirrus is the largest, yet the most uncertain, aviation climate impact term. A newly implemented contrail cirrus scheme in a double-moment cloud microphysics scheme in climate model realistically reproduces the contrail evolution and provides regional forcing estimates within the range reported by other models. The work highlights the importance of initial contrail characteristics and the need for detailed cloud particle representations in climate model contrail simulations.
Barbara Ervens, Ken S. Carslaw, Thomas Koop, and Ulrich Pöschl
Atmos. Chem. Phys., 25, 13903–13952, https://doi.org/10.5194/acp-25-13903-2025, https://doi.org/10.5194/acp-25-13903-2025, 2025
Short summary
Short summary
Over 25 years, the European Geosciences Union (EGU) has demonstrated the success, viability and benefits of interactive open-access (OA) publishing with public peer review in its journals, its publishing platform EGUsphere and virtual compilations. The article summarizes the evolution of the EGU/Copernicus publications and of OA publishing with interactive public peer review at large by placing the EGU/Copernicus publications in the context of current and future global open science.
Weronika Osmolska, Charles Chemel, Amanda Maycock, and Paul Field
Weather Clim. Dynam., 6, 1221–1240, https://doi.org/10.5194/wcd-6-1221-2025, https://doi.org/10.5194/wcd-6-1221-2025, 2025
Short summary
Short summary
Extreme cold temperatures have widespread impacts on health, agriculture, infrastructures and the economy. We develop for the first time a methodology to build a catalogue of cold spell events, tracked in space and time. This catalogue is used to examine the behaviour of cold spells and its climatology. The results reveal specific pathways through which cold air affect midlatitudes.
Xinyi Huang, Paul R. Field, Benjamin J. Murray, Daniel P. Grosvenor, Floortje van den Heuvel, and Kenneth S. Carslaw
Atmos. Chem. Phys., 25, 11363–11406, https://doi.org/10.5194/acp-25-11363-2025, https://doi.org/10.5194/acp-25-11363-2025, 2025
Short summary
Short summary
Cold-air outbreak (CAO) clouds play a vital role in climate prediction. This study explores the responses of CAO clouds to aerosols and ice production under different environmental conditions. We found that CAO cloud responses vary with cloud temperature and are strongly controlled by the liquid–ice partitioning in these clouds, suggesting the importance of good representations of cloud microphysics properties to predict the behaviours of CAO clouds in a warming climate.
K. S. Apsara, Aravindakshan Jayakumar, Theethai Jacob Anurose, Saji Mohandas, Paul R. Field, Thara Prabhakaran, Mahen Konwar, and Vijayapurapu Srinivasa Prasad
Atmos. Chem. Phys., 25, 11423–11439, https://doi.org/10.5194/acp-25-11423-2025, https://doi.org/10.5194/acp-25-11423-2025, 2025
Short summary
Short summary
Science has made significant strides in weather prediction, especially for intense tropical rainfall that can lead to floods and landslides. Our study aims to improve monsoon rainfall forecasts by analyzing raindrop sizes. Using a new approach to model raindrop growth, we achieved a more accurate depiction of large rainfall events. These improvements can be generalized to enhance early warning systems, offering reliable predictions that help reduce risks from severe tropical weather events.
Pratapaditya Ghosh, Ian Boutle, Paul Field, Adrian Hill, Marie Mazoyer, Katherine J. Evans, Salil Mahajan, Hyun-Gyu Kang, Min Xu, Wei Zhang, and Hamish Gordon
Atmos. Chem. Phys., 25, 11157–11182, https://doi.org/10.5194/acp-25-11157-2025, https://doi.org/10.5194/acp-25-11157-2025, 2025
Short summary
Short summary
We study the life cycle of fog events in Europe using a weather and climate model. By incorporating droplet formation and growth driven by radiative cooling, our model better simulates the total liquid water in foggy atmospheric columns. We show that both adiabatic and radiative cooling play significant, often equally important, roles in driving droplet formation and growth. We discuss strategies to address droplet number overpredictions by improving model physics and addressing model artifacts.
Declan L. Finney, Alan M. Blyth, Paul R. Field, Martin I. Daily, Benjamin J. Murray, Mengyu Sun, Paul J. Connolly, Zhiqiang Cui, and Steven Böing
Atmos. Chem. Phys., 25, 10907–10929, https://doi.org/10.5194/acp-25-10907-2025, https://doi.org/10.5194/acp-25-10907-2025, 2025
Short summary
Short summary
We present observation-informed modelling from the Deep Convective Microphysics Experiment (DCMEX) to study how environmental conditions and cloud processes affect anvil cloud albedo and radiation. Aerosols influencing cloud droplets or influencing ice formation yield varying radiative effects. We introduce fingerprint metrics to discern these effects. Using detailed observations and modelling, we offer insights into high-cloud radiative effects and feedbacks.
Xuemei Wang, Kenneth S. Carslaw, Daniel P. Grosvenor, and Hamish Gordon
Atmos. Chem. Phys., 25, 9685–9717, https://doi.org/10.5194/acp-25-9685-2025, https://doi.org/10.5194/acp-25-9685-2025, 2025
Short summary
Short summary
Anthropogenic emissions can influence aerosol particle number concentrations and cloud formation. Our model simulations predict around a 10 % increase in the particle and cloud droplet number concentrations when doubling the emissions in the Manaus region in the Amazonian wet season. However, the corresponding changes in cloud water and rain mass are around 4 %. Such a weak response implies that this convective environment is not sensitive to the localized anthropogenic emission changes here.
Pratapaditya Ghosh, Katherine J. Evans, Daniel P. Grosvenor, Hyun-Gyu Kang, Salil Mahajan, Min Xu, Wei Zhang, and Hamish Gordon
Geosci. Model Dev., 18, 4899–4913, https://doi.org/10.5194/gmd-18-4899-2025, https://doi.org/10.5194/gmd-18-4899-2025, 2025
Short summary
Short summary
The most popular algorithm for calculating cloud droplet number concentrations in climate models is sensitive to parameters that control simulated aerosol particle number concentrations at different sizes. We recommend small modifications to functions in the algorithm to improve its performance. Implementing the changes in the UK Met Office climate model reduced average bias in simulated global droplet number concentrations, leading to more reflected solar radiation and a net cooling effect.
Ross J. Herbert, Andrew I. L. Williams, Philipp Weiss, Duncan Watson-Parris, Elisabeth Dingley, Daniel Klocke, and Philip Stier
Atmos. Chem. Phys., 25, 7789–7814, https://doi.org/10.5194/acp-25-7789-2025, https://doi.org/10.5194/acp-25-7789-2025, 2025
Short summary
Short summary
Clouds exist at scales that climate models struggle to represent, limiting our knowledge of how climate change may impact clouds. Here we use a new kilometer-scale global model representing an important step towards the necessary scale. We focus on how aerosol particles modify clouds, radiation, and precipitation. We find the magnitude and manner of responses tend to vary from region to region, highlighting the potential of global kilometer-scale simulations and a need to represent aerosols in climate models.
Emma Sands, Ruth M. Doherty, Fiona M. O'Connor, Richard J. Pope, James Weber, and Daniel P. Grosvenor
Atmos. Chem. Phys., 25, 7269–7297, https://doi.org/10.5194/acp-25-7269-2025, https://doi.org/10.5194/acp-25-7269-2025, 2025
Short summary
Short summary
We perform a detailed satellite–model comparison for isoprene, formaldehyde and aerosol optical depth in an Earth system model. We quantify the impacts of several processes that affect how biosphere–atmosphere interactions influence atmospheric chemistry and aerosols. Our findings highlight that the aerosol direct effect is sensitive to the processes studied. These results can inform future investigations of how the biosphere can affect atmospheric composition and climate.
Mike Bush, David L. A. Flack, Huw W. Lewis, Sylvia I. Bohnenstengel, Chris J. Short, Charmaine Franklin, Adrian P. Lock, Martin Best, Paul Field, Anne McCabe, Kwinten Van Weverberg, Segolene Berthou, Ian Boutle, Jennifer K. Brooke, Seb Cole, Shaun Cooper, Gareth Dow, John Edwards, Anke Finnenkoetter, Kalli Furtado, Kate Halladay, Kirsty Hanley, Margaret A. Hendry, Adrian Hill, Aravindakshan Jayakumar, Richard W. Jones, Humphrey Lean, Joshua C. K. Lee, Andy Malcolm, Marion Mittermaier, Saji Mohandas, Stuart Moore, Cyril Morcrette, Rachel North, Aurore Porson, Susan Rennie, Nigel Roberts, Belinda Roux, Claudio Sanchez, Chun-Hsu Su, Simon Tucker, Simon Vosper, David Walters, James Warner, Stuart Webster, Mark Weeks, Jonathan Wilkinson, Michael Whitall, Keith D. Williams, and Hugh Zhang
Geosci. Model Dev., 18, 3819–3855, https://doi.org/10.5194/gmd-18-3819-2025, https://doi.org/10.5194/gmd-18-3819-2025, 2025
Short summary
Short summary
RAL configurations define settings for the Unified Model atmosphere and Joint UK Land Environment Simulator. The third version of the Regional Atmosphere and Land (RAL3) science configuration for kilometre- and sub-kilometre-scale modelling represents a major advance compared to previous versions (RAL2) by delivering a common science definition for applications in tropical and mid-latitude regions. RAL3 has more realistic precipitation distributions and an improved representation of clouds and visibility.
Philipp Weiss, Ross Herbert, and Philip Stier
Geosci. Model Dev., 18, 3877–3894, https://doi.org/10.5194/gmd-18-3877-2025, https://doi.org/10.5194/gmd-18-3877-2025, 2025
Short summary
Short summary
Aerosols strongly influence Earth's climate as they interact with radiation and clouds. New Earth system models run at resolutions of a few kilometers. To simulate the Earth system with interactive aerosols, we developed a new aerosol module. It represents aerosols as an ensemble of lognormal modes with given sizes and compositions. We present a year-long simulation with four modes at a resolution of 5 km. It captures key processes like the formation of dust storms in the Sahara.
Kathleen A. Alden, Paul Bieber, Anna J. Miller, Nicole Link, Benjamin J. Murray, and Nadine Borduas-Dedekind
Atmos. Chem. Phys., 25, 6179–6195, https://doi.org/10.5194/acp-25-6179-2025, https://doi.org/10.5194/acp-25-6179-2025, 2025
Short summary
Short summary
Lignin and Snomax are surface-active macromolecules that show a relationship between increasing concentrations, decreasing surface tension, and increasing ice-nucleating ability. However, this relationship did not hold for agricultural soil extracts collected in the UK and Canada. To explain this difference, we propose that as the complexity of the sample increases, the hydrophobic interfaces in the bulk compete with the air–water interface.
James Brean, David C. S. Beddows, Eija Asmi, Aki Virkkula, Lauriane L. J. Quéléver, Mikko Sipilä, Floortje Van Den Heuvel, Thomas Lachlan-Cope, Anna Jones, Markus Frey, Angelo Lupi, Jiyeon Park, Young Jun Yoon, Rolf Weller, Giselle L. Marincovich, Gabriela C. Mulena, Roy M. Harrison, and Manuel Dall'Osto
Atmos. Chem. Phys., 25, 1145–1162, https://doi.org/10.5194/acp-25-1145-2025, https://doi.org/10.5194/acp-25-1145-2025, 2025
Short summary
Short summary
Our results emphasise how understanding the geographical variation in surface types across the Antarctic is key to understanding secondary aerosol sources.
Ulrike Proske, Michael P. Adams, Grace C. E. Porter, Mark A. Holden, Jaana Bäck, and Benjamin J. Murray
Atmos. Chem. Phys., 25, 979–995, https://doi.org/10.5194/acp-25-979-2025, https://doi.org/10.5194/acp-25-979-2025, 2025
Short summary
Short summary
Ice-nucleating particles (INPs) aid the freezing of water droplets in clouds and thus modify cloud properties. In a campaign in a Finnish boreal forest, biological INPs were observed, despite many of their potential biological sources being snow-covered. We sampled tree-dwelling lichens that were not covered in snow and tested their ice nucleation ability in the laboratory. We found that the lichen harbours INPs, which may be important in similar snowy environments.
Weiyu Zhang, Kwinten Van Weverberg, Cyril J. Morcrette, Wuhu Feng, Kalli Furtado, Paul R. Field, Chih-Chieh Chen, Andrew Gettelman, Piers M. Forster, Daniel R. Marsh, and Alexandru Rap
Atmos. Chem. Phys., 25, 473–489, https://doi.org/10.5194/acp-25-473-2025, https://doi.org/10.5194/acp-25-473-2025, 2025
Short summary
Short summary
Contrail cirrus is the largest, but also most uncertain, contribution of aviation to global warming. We evaluate, for the first time, the impact of the host climate model on contrail cirrus properties. Substantial differences exist between contrail cirrus formation, persistence, and radiative effects in the host climate models. Reliable contrail cirrus simulations require advanced representation of cloud optical properties and microphysics, which should be better constrained by observations.
Ross J. Herbert, Alberto Sanchez-Marroquin, Daniel P. Grosvenor, Kirsty J. Pringle, Stephen R. Arnold, Benjamin J. Murray, and Kenneth S. Carslaw
Atmos. Chem. Phys., 25, 291–325, https://doi.org/10.5194/acp-25-291-2025, https://doi.org/10.5194/acp-25-291-2025, 2025
Short summary
Short summary
Aerosol particles that help form ice in clouds vary in number and type around the world and with time. However, in many weather and climate models cloud ice is not linked to aerosols that are known to nucleate ice. Here we report the first steps towards representing ice-nucleating particles within the UK Earth System Model. We conclude that in addition to ice nucleation by sea spray and mineral components of soil dust, we also need to represent ice nucleation by the organic components of soils.
Erin N. Raif, Sarah L. Barr, Mark D. Tarn, James B. McQuaid, Martin I. Daily, Steven J. Abel, Paul A. Barrett, Keith N. Bower, Paul R. Field, Kenneth S. Carslaw, and Benjamin J. Murray
Atmos. Chem. Phys., 24, 14045–14072, https://doi.org/10.5194/acp-24-14045-2024, https://doi.org/10.5194/acp-24-14045-2024, 2024
Short summary
Short summary
Ice-nucleating particles (INPs) allow ice to form in clouds at temperatures warmer than −35°C. We measured INP concentrations over the Norwegian and Barents seas in weather events where cold air is ejected from the Arctic. These concentrations were among the highest measured in the Arctic. It is likely that the INPs were transported to the Arctic from distant regions. These results show it is important to consider hemispheric-scale INP processes to understand INP concentrations in the Arctic.
Masaru Yoshioka, Daniel P. Grosvenor, Ben B. B. Booth, Colin P. Morice, and Ken S. Carslaw
Atmos. Chem. Phys., 24, 13681–13692, https://doi.org/10.5194/acp-24-13681-2024, https://doi.org/10.5194/acp-24-13681-2024, 2024
Short summary
Short summary
A 2020 regulation has reduced sulfur emissions from shipping by about 80 %, leading to a decrease in atmospheric aerosols that have a cooling effect primarily by affecting cloud properties and amounts. Our climate model simulations predict a global temperature increase of 0.04 K over the next 3 decades as a result, which could contribute to surpassing the Paris Agreement's 1.5 °C target. Reduced aerosols may have also contributed to the recent temperature spikes.
Franziska Vogel, Michael P. Adams, Larissa Lacher, Polly B. Foster, Grace C. E. Porter, Barbara Bertozzi, Kristina Höhler, Julia Schneider, Tobias Schorr, Nsikanabasi S. Umo, Jens Nadolny, Zoé Brasseur, Paavo Heikkilä, Erik S. Thomson, Nicole Büttner, Martin I. Daily, Romy Fösig, Alexander D. Harrison, Jorma Keskinen, Ulrike Proske, Jonathan Duplissy, Markku Kulmala, Tuukka Petäjä, Ottmar Möhler, and Benjamin J. Murray
Atmos. Chem. Phys., 24, 11737–11757, https://doi.org/10.5194/acp-24-11737-2024, https://doi.org/10.5194/acp-24-11737-2024, 2024
Short summary
Short summary
Primary ice formation in clouds strongly influences their properties; hence, it is important to understand the sources of ice-nucleating particles (INPs) and their variability. We present 2 months of INP measurements in a Finnish boreal forest using a new semi-autonomous INP counting device based on gas expansion. These results show strong variability in INP concentrations, and we present a case that the INPs we observe are, at least some of the time, of biological origin.
Xinyue Shao, Minghuai Wang, Xinyi Dong, Yaman Liu, Wenxiang Shen, Stephen R. Arnold, Leighton A. Regayre, Meinrat O. Andreae, Mira L. Pöhlker, Duseong S. Jo, Man Yue, and Ken S. Carslaw
Atmos. Chem. Phys., 24, 11365–11389, https://doi.org/10.5194/acp-24-11365-2024, https://doi.org/10.5194/acp-24-11365-2024, 2024
Short summary
Short summary
Highly oxygenated organic molecules (HOMs) play an important role in atmospheric new particle formation (NPF). By semi-explicitly coupling the chemical mechanism of HOMs and a comprehensive nucleation scheme in a global climate model, the updated model shows better agreement with measurements of nucleation rate, growth rate, and NPF event frequency. Our results reveal that HOM-driven NPF leads to a considerable increase in particle and cloud condensation nuclei burden globally.
Mark D. Tarn, Bethany V. Wyld, Naama Reicher, Matan Alayof, Daniella Gat, Alberto Sanchez-Marroquin, Sebastien N. F. Sikora, Alexander D. Harrison, Yinon Rudich, and Benjamin J. Murray
Aerosol Research, 2, 161–182, https://doi.org/10.5194/ar-2-161-2024, https://doi.org/10.5194/ar-2-161-2024, 2024
Short summary
Short summary
Ambient ice-nucleating particle (INP) concentrations were measured in Israel, which experiences air masses from a variety of sources. We found that the INP activity is typically dominated by K-feldspar mineral dust but that air masses passing over regions of fertile soils correlated with high INP concentrations and indicators of biological activity. This suggests that these fertile regions could be sporadic sources of warm-temperature biogenic INPs and warrants further study of these areas.
Declan L. Finney, Alan M. Blyth, Martin Gallagher, Huihui Wu, Graeme J. Nott, Michael I. Biggerstaff, Richard G. Sonnenfeld, Martin Daily, Dan Walker, David Dufton, Keith Bower, Steven Böing, Thomas Choularton, Jonathan Crosier, James Groves, Paul R. Field, Hugh Coe, Benjamin J. Murray, Gary Lloyd, Nicholas A. Marsden, Michael Flynn, Kezhen Hu, Navaneeth M. Thamban, Paul I. Williams, Paul J. Connolly, James B. McQuaid, Joseph Robinson, Zhiqiang Cui, Ralph R. Burton, Gordon Carrie, Robert Moore, Steven J. Abel, Dave Tiddeman, and Graydon Aulich
Earth Syst. Sci. Data, 16, 2141–2163, https://doi.org/10.5194/essd-16-2141-2024, https://doi.org/10.5194/essd-16-2141-2024, 2024
Short summary
Short summary
The DCMEX (Deep Convective Microphysics Experiment) project undertook an aircraft- and ground-based measurement campaign of New Mexico deep convective clouds during July–August 2022. The campaign coordinated a broad range of instrumentation measuring aerosol, cloud physics, radar signals, thermodynamics, dynamics, electric fields, and weather. The project's objectives included the utilisation of these data with satellite observations to study the anvil cloud radiative effect.
Larissa Lacher, Michael P. Adams, Kevin Barry, Barbara Bertozzi, Heinz Bingemer, Cristian Boffo, Yannick Bras, Nicole Büttner, Dimitri Castarede, Daniel J. Cziczo, Paul J. DeMott, Romy Fösig, Megan Goodell, Kristina Höhler, Thomas C. J. Hill, Conrad Jentzsch, Luis A. Ladino, Ezra J. T. Levin, Stephan Mertes, Ottmar Möhler, Kathryn A. Moore, Benjamin J. Murray, Jens Nadolny, Tatjana Pfeuffer, David Picard, Carolina Ramírez-Romero, Mickael Ribeiro, Sarah Richter, Jann Schrod, Karine Sellegri, Frank Stratmann, Benjamin E. Swanson, Erik S. Thomson, Heike Wex, Martin J. Wolf, and Evelyn Freney
Atmos. Chem. Phys., 24, 2651–2678, https://doi.org/10.5194/acp-24-2651-2024, https://doi.org/10.5194/acp-24-2651-2024, 2024
Short summary
Short summary
Aerosol particles that trigger ice formation in clouds are important for the climate system but are very rare in the atmosphere, challenging measurement techniques. Here we compare three cloud chambers and seven methods for collecting aerosol particles on filters for offline analysis at a mountaintop station. A general good agreement of the methods was found when sampling aerosol particles behind a whole air inlet, supporting their use for obtaining data that can be implemented in models.
Joel Ponsonby, Leon King, Benjamin J. Murray, and Marc E. J. Stettler
Atmos. Chem. Phys., 24, 2045–2058, https://doi.org/10.5194/acp-24-2045-2024, https://doi.org/10.5194/acp-24-2045-2024, 2024
Short summary
Short summary
Aerosol emissions from aircraft engines contribute to the formation of contrails, which have a climate impact as important as that of aviation’s CO2 emissions. For the first time, we experimentally investigate the freezing behaviour of water droplets formed on jet lubrication oil aerosol. We show that they can activate to form water droplets and discuss their potential impact on contrail formation. Our study has implications for contrails produced by future aircraft engine and fuel technologies.
Rolf Müller, Ulrich Pöschl, Thomas Koop, Thomas Peter, and Ken Carslaw
Atmos. Chem. Phys., 23, 15445–15453, https://doi.org/10.5194/acp-23-15445-2023, https://doi.org/10.5194/acp-23-15445-2023, 2023
Short summary
Short summary
Paul J. Crutzen was a pioneer in atmospheric sciences and a kind-hearted, humorous person with empathy for the private lives of his colleagues and students. He made fundamental scientific contributions to a wide range of scientific topics in all parts of the atmosphere. Paul was among the founders of the journal Atmospheric Chemistry and Physics. His work will continue to be a guide for generations of scientists and environmental policymakers to come.
Hamza Ahsan, Hailong Wang, Jingbo Wu, Mingxuan Wu, Steven J. Smith, Susanne Bauer, Harrison Suchyta, Dirk Olivié, Gunnar Myhre, Hitoshi Matsui, Huisheng Bian, Jean-François Lamarque, Ken Carslaw, Larry Horowitz, Leighton Regayre, Mian Chin, Michael Schulz, Ragnhild Bieltvedt Skeie, Toshihiko Takemura, and Vaishali Naik
Atmos. Chem. Phys., 23, 14779–14799, https://doi.org/10.5194/acp-23-14779-2023, https://doi.org/10.5194/acp-23-14779-2023, 2023
Short summary
Short summary
We examine the impact of the assumed effective height of SO2 injection, SO2 and BC emission seasonality, and the assumed fraction of SO2 emissions injected as SO4 on climate and chemistry model results. We find that the SO2 injection height has a large impact on surface SO2 concentrations and, in some models, radiative flux. These assumptions are a
hiddensource of inter-model variability and may be leading to bias in some climate model results.
Alberto Sanchez-Marroquin, Sarah L. Barr, Ian T. Burke, James B. McQuaid, and Benjamin J. Murray
Atmos. Chem. Phys., 23, 13819–13834, https://doi.org/10.5194/acp-23-13819-2023, https://doi.org/10.5194/acp-23-13819-2023, 2023
Short summary
Short summary
The sources and concentrations of ice-nucleating particles (INPs) in the Arctic are still poorly understood. Here we report aircraft-based INP concentrations and aerosol composition in the western North American Arctic. The concentrations of INPs and all aerosol particles were low. The aerosol samples contained mostly sea salt and dust particles. Dust particles were more relevant for the INP concentrations than sea salt. However, dust alone cannot account for all of the measured INPs.
Leighton A. Regayre, Lucia Deaconu, Daniel P. Grosvenor, David M. H. Sexton, Christopher Symonds, Tom Langton, Duncan Watson-Paris, Jane P. Mulcahy, Kirsty J. Pringle, Mark Richardson, Jill S. Johnson, John W. Rostron, Hamish Gordon, Grenville Lister, Philip Stier, and Ken S. Carslaw
Atmos. Chem. Phys., 23, 8749–8768, https://doi.org/10.5194/acp-23-8749-2023, https://doi.org/10.5194/acp-23-8749-2023, 2023
Short summary
Short summary
Aerosol forcing of Earth’s energy balance has persisted as a major cause of uncertainty in climate simulations over generations of climate model development. We show that structural deficiencies in a climate model are exposed by comprehensively exploring parametric uncertainty and that these deficiencies limit how much the model uncertainty can be reduced through observational constraint. This provides a future pathway towards building models with greater physical realism and lower uncertainty.
Jonas Elm, Aladár Czitrovszky, Andreas Held, Annele Virtanen, Astrid Kiendler-Scharr, Benjamin J. Murray, Daniel McCluskey, Daniele Contini, David Broday, Eirini Goudeli, Hilkka Timonen, Joan Rosell-Llompart, Jose L. Castillo, Evangelia Diapouli, Mar Viana, Maria E. Messing, Markku Kulmala, Naděžda Zíková, and Sebastian H. Schmitt
Aerosol Research, 1, 13–16, https://doi.org/10.5194/ar-1-13-2023, https://doi.org/10.5194/ar-1-13-2023, 2023
Robert Wagner, Alexander D. James, Victoria L. Frankland, Ottmar Möhler, Benjamin J. Murray, John M. C. Plane, Harald Saathoff, Ralf Weigel, and Martin Schnaiter
Atmos. Chem. Phys., 23, 6789–6811, https://doi.org/10.5194/acp-23-6789-2023, https://doi.org/10.5194/acp-23-6789-2023, 2023
Short summary
Short summary
Polar stratospheric clouds (PSCs) play an important role in the depletion of stratospheric ozone. They can consist of different chemical species, including crystalline nitric acid hydrates. We found that mineral dust or meteoric ablation material can efficiently catalyse the formation of a specific phase of nitric acid dihydrate crystals. We determined predominant particle shapes and infrared optical properties of these crystals, which are important inputs for remote sensing detection of PSCs.
Daniel P. Grosvenor and Kenneth S. Carslaw
Atmos. Chem. Phys., 23, 6743–6773, https://doi.org/10.5194/acp-23-6743-2023, https://doi.org/10.5194/acp-23-6743-2023, 2023
Short summary
Short summary
We determine what causes long-term trends in short-wave (SW) radiative fluxes in two climate models. A positive trend occurs between 1850 and 1970 (increasing SW reflection) and a negative trend between 1970 and 2014; the pre-1970 positive trend is mainly driven by an increase in cloud droplet number concentrations due to increases in aerosol, and the 1970–2014 trend is driven by a decrease in cloud fraction, which we attribute to changes in clouds caused by greenhouse gas-induced warming.
Ernesto Reyes-Villegas, Douglas Lowe, Jill S. Johnson, Kenneth S. Carslaw, Eoghan Darbyshire, Michael Flynn, James D. Allan, Hugh Coe, Ying Chen, Oliver Wild, Scott Archer-Nicholls, Alex Archibald, Siddhartha Singh, Manish Shrivastava, Rahul A. Zaveri, Vikas Singh, Gufran Beig, Ranjeet Sokhi, and Gordon McFiggans
Atmos. Chem. Phys., 23, 5763–5782, https://doi.org/10.5194/acp-23-5763-2023, https://doi.org/10.5194/acp-23-5763-2023, 2023
Short summary
Short summary
Organic aerosols (OAs), their sources and their processes remain poorly understood. The volatility basis set (VBS) approach, implemented in air quality models such as WRF-Chem, can be a useful tool to describe primary OA (POA) production and aging. However, the main disadvantage is its complexity. We used a Gaussian process simulator to reproduce model results and to estimate the sources of model uncertainty. We do this by comparing the outputs with OA observations made at Delhi, India, in 2018.
Gillian Young McCusker, Jutta Vüllers, Peggy Achtert, Paul Field, Jonathan J. Day, Richard Forbes, Ruth Price, Ewan O'Connor, Michael Tjernström, John Prytherch, Ryan Neely III, and Ian M. Brooks
Atmos. Chem. Phys., 23, 4819–4847, https://doi.org/10.5194/acp-23-4819-2023, https://doi.org/10.5194/acp-23-4819-2023, 2023
Short summary
Short summary
In this study, we show that recent versions of two atmospheric models – the Unified Model and Integrated Forecasting System – overestimate Arctic cloud fraction within the lower troposphere by comparison with recent remote-sensing measurements made during the Arctic Ocean 2018 expedition. The overabundance of cloud is interlinked with the modelled thermodynamic structure, with strong negative temperature biases coincident with these overestimated cloud layers.
Ross Herbert and Philip Stier
Atmos. Chem. Phys., 23, 4595–4616, https://doi.org/10.5194/acp-23-4595-2023, https://doi.org/10.5194/acp-23-4595-2023, 2023
Short summary
Short summary
We provide robust evidence from multiple sources showing that smoke from fires in the Amazon rainforest significantly modifies the diurnal cycle of convection and cools the climate. Low to moderate amounts of smoke increase deep convective clouds and rain, whilst beyond a threshold amount, the smoke starts to suppress the convection and rain. We are currently at this threshold, suggesting increases in fires from agricultural practices or droughts will reduce cloudiness and rain over the region.
Xuemei Wang, Hamish Gordon, Daniel P. Grosvenor, Meinrat O. Andreae, and Ken S. Carslaw
Atmos. Chem. Phys., 23, 4431–4461, https://doi.org/10.5194/acp-23-4431-2023, https://doi.org/10.5194/acp-23-4431-2023, 2023
Short summary
Short summary
New particle formation in the upper troposphere is important for the global boundary layer aerosol population, and they can be transported downward in Amazonia. We use a global and a regional model to quantify the number of aerosols that are formed at high altitude and transported downward in a 1000 km region. We find that the majority of the aerosols are from outside the region. This suggests that the 1000 km region is unlikely to be a
closed loopfor aerosol formation, transport and growth.
Ruth Price, Andrea Baccarini, Julia Schmale, Paul Zieger, Ian M. Brooks, Paul Field, and Ken S. Carslaw
Atmos. Chem. Phys., 23, 2927–2961, https://doi.org/10.5194/acp-23-2927-2023, https://doi.org/10.5194/acp-23-2927-2023, 2023
Short summary
Short summary
Arctic clouds can control how much energy is absorbed by the surface or reflected back to space. Using a computer model of the atmosphere we investigated the formation of atmospheric particles that allow cloud droplets to form. We found that particles formed aloft are transported to the lowest part of the Arctic atmosphere and that this is a key source of particles. Our results have implications for the way Arctic clouds will behave in the future as climate change continues to impact the region.
Alexander D. James, Finn Pace, Sebastien N. F. Sikora, Graham W. Mann, John M. C. Plane, and Benjamin J. Murray
Atmos. Chem. Phys., 23, 2215–2233, https://doi.org/10.5194/acp-23-2215-2023, https://doi.org/10.5194/acp-23-2215-2023, 2023
Short summary
Short summary
Here, we examine whether several materials of meteoric origin can nucleate crystallisation in stratospheric cloud droplets which would affect ozone depletion. We find that material which could fragment on atmospheric entry without melting is unlikely to be present in high enough concentration in the stratosphere to contribute to observed crystalline clouds. Material which ablates completely then forms a new solid known as meteoric smoke can provide enough nucleation to explain observed clouds.
Leighton A. Regayre, Lucia Deaconu, Daniel P. Grosvenor, David Sexton, Christopher C. Symonds, Tom Langton, Duncan Watson-Paris, Jane P. Mulcahy, Kirsty J. Pringle, Mark Richardson, Jill S. Johnson, John Rostron, Hamish Gordon, Grenville Lister, Philip Stier, and Ken S. Carslaw
EGUsphere, https://doi.org/10.5194/egusphere-2022-1330, https://doi.org/10.5194/egusphere-2022-1330, 2022
Preprint archived
Short summary
Short summary
We show that potential structural deficiencies in a climate model can be exposed by comprehensively exploring its parametric uncertainty, and that these deficiencies limit how much the model uncertainty can be reduced through observational constraint. Combined consideration of parametric and structural uncertainties provides a future pathway towards building models that have greater physical realism and lower uncertainty.
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
Short summary
Short summary
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.
Johannes Quaas, Hailing Jia, Chris Smith, Anna Lea Albright, Wenche Aas, Nicolas Bellouin, Olivier Boucher, Marie Doutriaux-Boucher, Piers M. Forster, Daniel Grosvenor, Stuart Jenkins, Zbigniew Klimont, Norman G. Loeb, Xiaoyan Ma, Vaishali Naik, Fabien Paulot, Philip Stier, Martin Wild, Gunnar Myhre, and Michael Schulz
Atmos. Chem. Phys., 22, 12221–12239, https://doi.org/10.5194/acp-22-12221-2022, https://doi.org/10.5194/acp-22-12221-2022, 2022
Short summary
Short summary
Pollution particles cool climate and offset part of the global warming. However, they are washed out by rain and thus their effect responds quickly to changes in emissions. We show multiple datasets to demonstrate that aerosol emissions and their concentrations declined in many regions influenced by human emissions, as did the effects on clouds. Consequently, the cooling impact on the Earth energy budget became smaller. This change in trend implies a relative warming.
Outi Meinander, Pavla Dagsson-Waldhauserova, Pavel Amosov, Elena Aseyeva, Cliff Atkins, Alexander Baklanov, Clarissa Baldo, Sarah L. Barr, Barbara Barzycka, Liane G. Benning, Bojan Cvetkovic, Polina Enchilik, Denis Frolov, Santiago Gassó, Konrad Kandler, Nikolay Kasimov, Jan Kavan, James King, Tatyana Koroleva, Viktoria Krupskaya, Markku Kulmala, Monika Kusiak, Hanna K. Lappalainen, Michał Laska, Jerome Lasne, Marek Lewandowski, Bartłomiej Luks, James B. McQuaid, Beatrice Moroni, Benjamin Murray, Ottmar Möhler, Adam Nawrot, Slobodan Nickovic, Norman T. O’Neill, Goran Pejanovic, Olga Popovicheva, Keyvan Ranjbar, Manolis Romanias, Olga Samonova, Alberto Sanchez-Marroquin, Kerstin Schepanski, Ivan Semenkov, Anna Sharapova, Elena Shevnina, Zongbo Shi, Mikhail Sofiev, Frédéric Thevenet, Throstur Thorsteinsson, Mikhail Timofeev, Nsikanabasi Silas Umo, Andreas Uppstu, Darya Urupina, György Varga, Tomasz Werner, Olafur Arnalds, and Ana Vukovic Vimic
Atmos. Chem. Phys., 22, 11889–11930, https://doi.org/10.5194/acp-22-11889-2022, https://doi.org/10.5194/acp-22-11889-2022, 2022
Short summary
Short summary
High-latitude dust (HLD) is a short-lived climate forcer, air pollutant, and nutrient source. Our results suggest a northern HLD belt at 50–58° N in Eurasia and 50–55° N in Canada and at >60° N in Eurasia and >58° N in Canada. Our addition to the previously identified global dust belt (GDB) provides crucially needed information on the extent of active HLD sources with both direct and indirect impacts on climate and environment in remote regions, which are often poorly understood and predicted.
Amy H. Peace, Ben B. B. Booth, Leighton A. Regayre, Ken S. Carslaw, David M. H. Sexton, Céline J. W. Bonfils, and John W. Rostron
Earth Syst. Dynam., 13, 1215–1232, https://doi.org/10.5194/esd-13-1215-2022, https://doi.org/10.5194/esd-13-1215-2022, 2022
Short summary
Short summary
Anthropogenic aerosol emissions have been linked to driving climate responses such as shifts in the location of tropical rainfall. However, the interaction of aerosols with climate remains one of the most uncertain aspects of climate modelling and limits our ability to predict future climate change. We use an ensemble of climate model simulations to investigate what impact the large uncertainty in how aerosols interact with climate has on predicting future tropical rainfall shifts.
Alexander D. Harrison, Daniel O'Sullivan, Michael P. Adams, Grace C. E. Porter, Edmund Blades, Cherise Brathwaite, Rebecca Chewitt-Lucas, Cassandra Gaston, Rachel Hawker, Ovid O. Krüger, Leslie Neve, Mira L. Pöhlker, Christopher Pöhlker, Ulrich Pöschl, Alberto Sanchez-Marroquin, Andrea Sealy, Peter Sealy, Mark D. Tarn, Shanice Whitehall, James B. McQuaid, Kenneth S. Carslaw, Joseph M. Prospero, and Benjamin J. Murray
Atmos. Chem. Phys., 22, 9663–9680, https://doi.org/10.5194/acp-22-9663-2022, https://doi.org/10.5194/acp-22-9663-2022, 2022
Short summary
Short summary
The formation of ice in clouds fundamentally alters cloud properties; hence it is important we understand the special aerosol particles that can nucleate ice when immersed in supercooled cloud droplets. In this paper we show that African desert dust that has travelled across the Atlantic to the Caribbean nucleates ice much less well than we might have expected.
Martin I. Daily, Mark D. Tarn, Thomas F. Whale, and Benjamin J. Murray
Atmos. Meas. Tech., 15, 2635–2665, https://doi.org/10.5194/amt-15-2635-2022, https://doi.org/10.5194/amt-15-2635-2022, 2022
Short summary
Short summary
Mineral dust and particles of biological origin are important types of ice-nucleating particles (INPs) that can trigger ice formation of supercooled cloud droplets. Heat treatments are used to detect the presence of biological INPs in samples collected from the environment as the activity of mineral INPs is assumed unchanged, although not fully assessed. We show that the ice-nucleating ability of some minerals can change after heating and discuss how INP heat tests should be interpreted.
Zoé Brasseur, Dimitri Castarède, Erik S. Thomson, Michael P. Adams, Saskia Drossaart van Dusseldorp, Paavo Heikkilä, Kimmo Korhonen, Janne Lampilahti, Mikhail Paramonov, Julia Schneider, Franziska Vogel, Yusheng Wu, Jonathan P. D. Abbatt, Nina S. Atanasova, Dennis H. Bamford, Barbara Bertozzi, Matthew Boyer, David Brus, Martin I. Daily, Romy Fösig, Ellen Gute, Alexander D. Harrison, Paula Hietala, Kristina Höhler, Zamin A. Kanji, Jorma Keskinen, Larissa Lacher, Markus Lampimäki, Janne Levula, Antti Manninen, Jens Nadolny, Maija Peltola, Grace C. E. Porter, Pyry Poutanen, Ulrike Proske, Tobias Schorr, Nsikanabasi Silas Umo, János Stenszky, Annele Virtanen, Dmitri Moisseev, Markku Kulmala, Benjamin J. Murray, Tuukka Petäjä, Ottmar Möhler, and Jonathan Duplissy
Atmos. Chem. Phys., 22, 5117–5145, https://doi.org/10.5194/acp-22-5117-2022, https://doi.org/10.5194/acp-22-5117-2022, 2022
Short summary
Short summary
The present measurement report introduces the ice nucleation campaign organized in Hyytiälä, Finland, in 2018 (HyICE-2018). We provide an overview of the campaign settings, and we describe the measurement infrastructure and operating procedures used. In addition, we use results from ice nucleation instrument inter-comparison to show that the suite of these instruments deployed during the campaign reports consistent results.
Kalli Furtado and Paul Field
Atmos. Chem. Phys., 22, 3391–3407, https://doi.org/10.5194/acp-22-3391-2022, https://doi.org/10.5194/acp-22-3391-2022, 2022
Short summary
Short summary
The complex processes involved mean that no simple answer to this
question has so far been discovered: do aerosols increase or decrease precipitation? Using high-resolution weather simulations, we find a self-similar property of rainfall that is not affected by aerosols. Using this invariant, we can collapse all our simulations to a single curve. So, although aerosol effects on rain are many, there may be a universal constraint on the number of degrees of freedom needed to represent them.
Zhiqiang Cui, Alan Blyth, Yahui Huang, Gary Lloyd, Thomas Choularton, Keith Bower, Paul Field, Rachel Hawker, and Lindsay Bennett
Atmos. Chem. Phys., 22, 1649–1667, https://doi.org/10.5194/acp-22-1649-2022, https://doi.org/10.5194/acp-22-1649-2022, 2022
Short summary
Short summary
High concentrations of ice particles were observed at temperatures greater than about –8 C. The default scheme of the secondary ice production cannot explain the high concentrations. Relaxing the conditions for secondary ice production or considering dust aerosol alone is insufficient to produce the observed amount of ice particles. It is likely that multi-thermals play an important role in producing very high concentrations of secondary ice particles in some tropical clouds.
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
Short summary
Short summary
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.
Rachel E. Hawker, Annette K. Miltenberger, Jill S. Johnson, Jonathan M. Wilkinson, Adrian A. Hill, Ben J. Shipway, Paul R. Field, Benjamin J. Murray, and Ken S. Carslaw
Atmos. Chem. Phys., 21, 17315–17343, https://doi.org/10.5194/acp-21-17315-2021, https://doi.org/10.5194/acp-21-17315-2021, 2021
Short summary
Short summary
We find that ice-nucleating particles (INPs), aerosols that can initiate the freezing of cloud droplets, cause substantial changes to the properties of radiatively important convectively generated anvil cirrus. The number concentration of INPs had a large effect on ice crystal number concentration while the INP temperature dependence controlled ice crystal size and cloud fraction. The results indicate information on INP number and source is necessary for the representation of cloud glaciation.
Cited articles
Abel, S. J., Boutle, I. A., Waite, K., Fox, S., Brown, P. R. A., Cotton, R., Lloyd, G., Choularton, T. W., and Bower, K. N.: The role of precipitation in controlling the transition from stratocumulus to cumulus clouds in a Northern Hemisphere cold-air outbreak, J. Atmos. Sci., 74, 2293–2314, https://doi.org/10.1175/JAS-D-16-0362.1, 2017. a, b, c, d, e, f, g
Albrecht, B. A.: Aerosols, cloud microphysics, and fractional cloudiness, Science, 245, 1227–1230, https://doi.org/10.1126/science.245.4923.1227, 1989. a
Baran, A. J., Manners, J., Field, P. R., Furtado, K., and Hill, A.: A consistent coupling of two-moment microphysics and bulk ice optical properties, and its impact on radiation in a regional weather model, Q. J. Roy. Meteor. Soc., 151, e5025, https://doi.org/10.1002/qj.5025, 2025. a
Barr, S. L., Wyld, B., McQuaid, J. B., Neely III, R. R., and Murray, B. J.: Southern Alaska as a source of atmospheric mineral dust and ice-nucleating particles, Science Advances, 9, eadg3708, https://doi.org/10.1126/sciadv.adg3708, 2023. a
Bastos, L. S. and O'Hagan, A.: Diagnostics for Gaussian process emulators, Technometrics, 51, 425–438, https://doi.org/10.1198/TECH.2009.08019, 2009. a, b
Bergeron, T.: On the physics of clouds and precipitation, in: Proces Verbaux de l'Association de Météorologie, 5th General Assembly of the IUGG, Lisbon 1933, 156–178, 1935. a
Beven, K.: A manifesto for the equifinality thesis, J. Hydrol., 320, 18–36, https://doi.org/10.1016/j.jhydrol.2005.07.007, 2006. a
Bigg, E. K.: The formation of atmospheric ice crystals by the freezing of droplets, Q. J. Roy. Meteor. Soc., 79, 510–519, https://doi.org/10.1002/qj.49707934207, 1953. a
Bodas-Salcedo, A., Mulcahy, J. P., Andrews, T., Williams, K. D., Ringer, M. A., Field, P. R., and Elsaesser, G. S.: Strong dependence of atmospheric feedbacks on mixed-phase microphysics and aerosol-cloud interactions in HadGEM3, J. Adv. Model. Earth Sy., 11, 1735–1758, https://doi.org/10.1029/2019MS001688, 2019. a
Brown, A., Milton, S., Cullen, M., Golding, B., Mitchell, J., and Shelly, A.: Unified modeling and prediction of weather and climate: a 25-year journey, B. Am. Meteorol. Soc., 93, 1865–1877, https://doi.org/10.1175/BAMS-D-12-00018.1, 2012. a, b, c
Brümmer, B.: Boundary-layer modification in wintertime cold-air outbreaks from the Arctic sea ice, Bound.-Lay. Meteorol., 80, 109–125, https://doi.org/10.1007/BF00119014, 1996. a
Brümmer, B.: Roll and cell convection in wintertime Arctic cold-air outbreaks, J. Atmos. Sci., 56, 2613–2636, https://doi.org/10.1175/1520-0469(1999)056<2613:RACCIW>2.0.CO;2, 1999. a, b
Bush, M., Flack, D. L. A., Lewis, H. W., Bohnenstengel, S. I., Short, C. J., Franklin, C., Lock, A. P., Best, M., Field, P., McCabe, A., Van Weverberg, K., Berthou, S., Boutle, I., Brooke, J. K., Cole, S., Cooper, S., Dow, G., Edwards, J., Finnenkoetter, A., Furtado, K., Halladay, K., Hanley, K., Hendry, M. A., Hill, A., Jayakumar, A., Jones, R. W., Lean, H., Lee, J. C. K., Malcolm, A., Mittermaier, M., Mohandas, S., Moore, S., Morcrette, C., North, R., Porson, A., Rennie, S., Roberts, N., Roux, B., Sanchez, C., Su, C.-H., Tucker, S., Vosper, S., Walters, D., Warner, J., Webster, S., Weeks, M., Wilkinson, J., Whitall, M., Williams, K. D., and Zhang, H.: The third Met Office Unified Model–JULES Regional Atmosphere and Land Configuration, RAL3, Geosci. Model Dev., 18, 3819–3855, https://doi.org/10.5194/gmd-18-3819-2025, 2025. a
Carslaw, K. S., Regayre, L. A., Proske, U., Gettelman, A., Sexton, D. M. H., Qian, Y., Marshall, L. R., Wild, O., van Lier-Walqui, M., Oertel, A., Peatier, S., Yang, B., Johnson, J. S., Li, S., McCoy, D. T., Sanderson, B. M., Williamson, C. J., Elsaesser, G. S., Yamazaki, K., and Booth, B. B. B.: Opinion: The importance and future development of perturbed parameter ensembles in climate and atmospheric science, Atmos. Chem. Phys., 26, 4651–4667, https://doi.org/10.5194/acp-26-4651-2026, 2026. a
Ceppi, P., Brient, F., Zelinka, M. D., and Hartmann, D. L.: Cloud feedback mechanisms and their representation in global climate models, WIREs Clim. Change, 8, e465, https://doi.org/10.1002/wcc.465, 2017. a, b, c
Clarke, S. J., Abel, S. J., Nott, G. J., Raif, E. N., Tarn, M. D., Biggart, M., Wu, H., Ashmore, D. W., Barr, S. L., Barrett, P. A., Bower, K. N., Bowles, J., Connolly, P. J., Cotton, R., Evans, M. D., Flynn, M., Foster, P. B., Fox, S., Gallagher, M. W., Hu, K., Kent, J., Lloyd, G., Marsden, N. A., McQuaid, J. B., Robinson, J., Tiddeman, D., Wilson, A., Wivell, K., Field, P. R., Choularton, T. W., and Murray, B. J.: Marine cold-air outbreaks over the Norwegian–Barents and Labrador seas: observational datasets from the ACAO and M-Phase aircraft campaigns, ESS Open Archive, 2026, https://doi.org/10.22541/essoar.15004594/v1, 2026. a, b
Cotton, R. J., Field, P. R., Ulanowski, Z., Kaye, P. H., Hirst, E., Greenaway, R. S., Crawford, I., Crosier, J., and Dorsey, J.: The effective density of small ice particles obtained from in situ aircraft observations of mid-latitude cirrus, Q. J. Roy. Meteor. Soc., 139, 1923–1934, https://doi.org/10.1002/qj.2058, 2013. a
Creamean, J. M., Kirpes, R. M., Pratt, K. A., Spada, N. J., Maahn, M., de Boer, G., Schnell, R. C., and China, S.: Marine and terrestrial influences on ice nucleating particles during continuous springtime measurements in an Arctic oilfield location, Atmos. Chem. Phys., 18, 18023–18042, https://doi.org/10.5194/acp-18-18023-2018, 2018. a
Creamean, J. M., Cross, J. N., Pickart, R., McRaven, L., Lin, P., Pacini, A., Hanlon, R., Schmale, D. G., Ceniceros, J., Aydell, T., Colombi, N., Bolger, E., and DeMott, P. J.: Ice nucleating particles carried from below a phytoplankton bloom to the Arctic atmosphere, Geophys. Res. Lett., 46, 8572–8581, https://doi.org/10.1029/2019GL083039, 2019. a
DeMott, P. J., Prenni, A. J., McMeeking, G. R., Sullivan, R. C., Petters, M. D., Tobo, Y., Niemand, M., Möhler, O., Snider, J. R., Wang, Z., and Kreidenweis, S. M.: Integrating laboratory and field data to quantify the immersion freezing ice nucleation activity of mineral dust particles, Atmos. Chem. Phys., 15, 393–409, https://doi.org/10.5194/acp-15-393-2015, 2015. a
DeMott, P. J., Hill, T. C. J., McCluskey, C. S., Prather, K. A., Collins, D. B., Sullivan, R. C., Ruppel, M. J., Mason, R. H., Irish, V. E., Lee, T., Hwang, C. Y., Rhee, T. S., Snider, J. R., McMeeking, G. R., Dhaniyala, S., Lewis, E. R., Wentzell, J. J. B., Abbatt, J., Lee, C., Sultana, C. M., Ault, A. P., Axson, J. L., Martinez, M. D., Venero, I., Santos-Figueroa, G., Stokes, M. D., Deane, G. B., Mayol-Bracero, O. L., Grassian, V. H., Bertram, T. H., Bertram, A. K., Moffett, B. F., and Franc, G. D.: Sea spray aerosol as a unique source of ice nucleating particles, P. Natl. Acad. Sci. USA, 113, 5797–5803, https://doi.org/10.1073/pnas.1514034112, 2016. a
de Roode, S. R., Frederikse, T., Siebesma, A. P., Ackerman, A. S., Chylik, J., Field, P. R., Fricke, J., Gryschka, M., Hill, A., Honnert, R., Krueger, S. K., Lac, C., Lesage, A. T., and Tomassini, L.: Turbulent transport in the gray zone: a large eddy model intercomparison study of the CONSTRAIN cold air outbreak case, J. Adv. Model. Earth Sy., 11, 597–623, https://doi.org/10.1029/2018MS001443, 2019. a, b
Elsaesser, G. S., van Lier-Walqui, M., Yang, Q., Kelley, M., Ackerman, A. S., Fridlind, A. M., Cesana, G. V., Schmidt, G. A., Wu, J., Behrangi, A., Camargo, S. J., De, B., Inoue, K., Leitmann-Niimi, N. M., and Strong, J. D. O.: Using machine learning to generate a GISS ModelE Calibrated Physics Ensemble (CPE), J. Adv. Model. Earth Sy., 17, e2024MS004713, https://doi.org/10.1029/2024MS004713, 2025. a
Evans, M. D., Abel, S. J., Field, P. R., Finney, D. L., Lloyd, G., Cotton, R. J., Smith, D. K., Murray, B. J., and Huang, X.: Characterising the spatial overlap between liquid and ice in mixed-phase clouds, Q. J. Roy. Meteor. Soc., 151, e5041, https://doi.org/10.1002/qj.5041, 2025. a, b, c, d
Field, P. R., Cotton, R. J., McBeath, K., Lock, A. P., Webster, S., and Allan, R. P.: Improving a convection-permitting model simulation of a cold air outbreak, Q. J. Roy. Meteor. Soc., 140, 124–138, https://doi.org/10.1002/qj.2116, 2014. a, b
Field, P. R., Brožková, R., Chen, M., Dudhia, J., Lac, C., Hara, T., Honnert, R., Olson, J., Siebesma, P., de Roode, S., Tomassini, L., Hill, A., and McTaggart-Cowan, R.: Exploring the convective grey zone with regional simulations of a cold air outbreak, Q. J. Roy. Meteor. Soc., 143, 2537–2555, https://doi.org/10.1002/qj.3105, 2017. a
Field, P. R., Hill, A., Shipway, B., Furtado, K., Wilkinson, J., Miltenberger, A., Gordon, H., Grosvenor, D. P., Stevens, R., and Van Weverberg, K.: Implementation of a double moment cloud microphysics scheme in the UK met office regional numerical weather prediction model, Q. J. Roy. Meteor. Soc., https://doi.org/10.1002/qj.4414, 2023. a, b, c, d, e, f, g, h, i, j, k, l
Findeisen, W., Volken, E., Giesche, A. M., Brönnimann, S.: Colloidal meteorological processes in the formation of precipitation, Meteorol. Z., 24, 443–454, https://doi.org/10.1127/metz/2015/0675, 2015. a
Findeisen, W. and Findeisen, E.: Untersuchungen über die Eissplitterbildung an Reifschichten (Ein Beitrag zur Frage der Entstehung der Gewitterelektrizitat und zur Mikrostruktur der Cumulonimben), Meteor. Z., 60, 145–154, 1943. a
Fletcher, J., Mason, S., and Jakob, C.: The climatology, meteorology, and boundary layer structure of marine cold air outbreaks in both hemispheres, J. Climate, 29, 1999–2014, https://doi.org/10.1175/JCLI-D-15-0268.1, 2016a. a
Fletcher, J. K., Mason, S., and Jakob, C.: A climatology of clouds in marine cold air outbreaks in both hemispheres, J. Climate, 29, 6677–6692, https://doi.org/10.1175/JCLI-D-15-0783.1, 2016b. a, b
Forster, P., Storelvmo, T., Armour, K., Collins, W., Dufresne, J. L., Frame, D., Lunt, D. J., Mauritsen, T., Palmer, M. D., Watanabe, M., Wild, M., and Zhang, H.: The Earth's energy budget, climate feedbacks, and climate sensitivity, in: Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change, edited by: Masson-Delmotte, V., Zhai, P., Pirani, A., Connors, S. L., Péan, C., Berger, S., Caud, N., Chen, Y., Goldfarb, L., Gomis, M. I., Huang, M., Leitzell, K., Lonnoy, E., Matthews, J. B. R., Maycock, T. K., Waterfield, T., Yelekçi, O., Yu, R., and Zhou, B., book section 7, Cambridge University Press, Cambridge, UK and New York, NY, USA, https://doi.org/10.1017/9781009157896.009, 2021. a
Franz Conen, Emiliano Stopelli, L. Z.: Clues that decaying leaves enrich Arctic air with ice nucleating particles, Atmos. Environ., 129, 91–94, https://doi.org/10.1016/j.atmosenv.2016.01.027, 2016. a
Glassmeier, F., Hoffmann, F., Johnson, J. S., Yamaguchi, T., Carslaw, K. S., and Feingold, G.: An emulator approach to stratocumulus susceptibility, Atmos. Chem. Phys., 19, 10191–10203, https://doi.org/10.5194/acp-19-10191-2019, 2019. a
Grosvenor, D. P., Sourdeval, O., Zuidema, P., Ackerman, A., Alexandrov, M. D., Bennartz, R., Boers, R., Cairns, B., Chiu, J. C., Christensen, M., Deneke, H., Diamond, M., Feingold, G., Fridlind, A., Hünerbein, A., Knist, C., Kollias, P., Marshak, A., McCoy, D., Merk, D., Painemal, D., Rausch, J., Rosenfeld, D., Russchenberg, H., Seifert, P., Sinclair, K., Stier, P., van Diedenhoven, B., Wendisch, M., Werner, F., Wood, R., Zhang, Z., and Quaas, J.: Remote sensing of droplet number concentration in warm clouds: a review of the current state of knowledge and perspectives, Rev. Geophys., 56, 409–453, https://doi.org/10.1029/2017RG000593, 2018. a, b
Hallett, J. and Mossop, S. C.: Production of secondary ice particles during the riming process, Nature, 249, 26–28, 1974. a
Harrison, A. D., Lever, K., Sanchez-Marroquin, A., Holden, M. A., Whale, T. F., Tarn, M. D., McQuaid, J. B., and Murray, B. J.: The ice-nucleating ability of quartz immersed in water and its atmospheric importance compared to K-feldspar, Atmos. Chem. Phys., 19, 11343–11361, https://doi.org/10.5194/acp-19-11343-2019, 2019. a, b, c, d, e
Hartmann, M., Adachi, K., Eppers, O., Haas, C., Herber, A., Holzinger, R., Hünerbein, A., Jäkel, E., Jentzsch, C., van Pinxteren, M., Wex, H., Willmes, S., and Stratmann, F.: Wintertime airborne measurements of ice nucleating particles in the high Arctic: a hint to a marine, biogenic source for ice nucleating particles, Geophys. Res. Lett., 47, e2020GL087770, https://doi.org/10.1029/2020GL087770, 2020. a
Hartmann, M., Gong, X., Kecorius, S., van Pinxteren, M., Vogl, T., Welti, A., Wex, H., Zeppenfeld, S., Herrmann, H., Wiedensohler, A., and Stratmann, F.: Terrestrial or marine – indications towards the origin of ice-nucleating particles during melt season in the European Arctic up to 83.7° N, Atmos. Chem. Phys., 21, 11613–11636, https://doi.org/10.5194/acp-21-11613-2021, 2021. a
Hawker, R. E., Miltenberger, A. K., Johnson, J. S., Wilkinson, J. M., Hill, A. A., Shipway, B. J., Field, P. R., Murray, B. J., and Carslaw, K. S.: Model emulation to understand the joint effects of ice-nucleating particles and secondary ice production on deep convective anvil cirrus, Atmos. Chem. Phys., 21, 17315–17343, https://doi.org/10.5194/acp-21-17315-2021, 2021. a
Herbert, R. J., Sanchez-Marroquin, A., Grosvenor, D. P., Pringle, K. J., Arnold, S. R., Murray, B. J., and Carslaw, K. S.: Gaps in our understanding of ice-nucleating particle sources exposed by global simulation of the UK Earth System Model, Atmos. Chem. Phys., 25, 291–325, https://doi.org/10.5194/acp-25-291-2025, 2025. a, b, c
Huang, X., Field, P. R., Murray, B. J., Grosvenor, D. P., van den Heuvel, F., and Carslaw, K. S.: Different responses of cold-air outbreak clouds to aerosol and ice production depending on cloud temperature, Atmos. Chem. Phys., 25, 11363–11406, https://doi.org/10.5194/acp-25-11363-2025, 2025. a, b, c, d, e, f, g, h
Huang, X.: Model data from perturbed parameter ensemble simulations used in manuscript submitted to ACP “Interacting effects of droplet number and ice formation processes on mixed-phase cold-air outbreak clouds” (Version 1), Zenodo [data set], https://doi.org/10.5281/zenodo.18267702, 2026. a
Igel, A. L., van den Heever, S. C., and Johnson, J. S.: Meteorological and land surface properties impacting sea breeze extent and aerosol distribution in a dry environment, J. Geophys. Res.-Atmos., 123, 22–37, https://doi.org/10.1002/2017JD027339, 2018. a
Irish, V. E., Hanna, S. J., Willis, M. D., China, S., Thomas, J. L., Wentzell, J. J. B., Cirisan, A., Si, M., Leaitch, W. R., Murphy, J. G., Abbatt, J. P. D., Laskin, A., Girard, E., and Bertram, A. K.: Ice nucleating particles in the marine boundary layer in the Canadian Arctic during summer 2014, Atmos. Chem. Phys., 19, 1027–1039, https://doi.org/10.5194/acp-19-1027-2019, 2019. a
Johnson, J. S., Cui, Z., Lee, L. A., Gosling, J. P., Blyth, A. M., and Carslaw, K. S.: Evaluating uncertainty in convective cloud microphysics using statistical emulation, J. Adv. Model. Earth Sy., 7, 162–187, https://doi.org/10.1002/2014MS000383, 2015. a, b, c, d
Johnson, J. S., Regayre, L. A., Yoshioka, M., Pringle, K. J., Lee, L. A., Sexton, D. M. H., Rostron, J. W., Booth, B. B. B., and Carslaw, K. S.: The importance of comprehensive parameter sampling and multiple observations for robust constraint of aerosol radiative forcing, Atmos. Chem. Phys., 18, 13031–13053, https://doi.org/10.5194/acp-18-13031-2018, 2018. a
Johnson, J. S., Regayre, L. A., Yoshioka, M., Pringle, K. J., Turnock, S. T., Browse, J., Sexton, D. M. H., Rostron, J. W., Schutgens, N. A. J., Partridge, D. G., Liu, D., Allan, J. D., Coe, H., Ding, A., Cohen, D. D., Atanacio, A., Vakkari, V., Asmi, E., and Carslaw, K. S.: Robust observational constraint of uncertain aerosol processes and emissions in a climate model and the effect on aerosol radiative forcing, Atmos. Chem. Phys., 20, 9491–9524, https://doi.org/10.5194/acp-20-9491-2020, 2020. a
Jones, A. C., Hill, A., Hemmings, J., Lemaitre, P., Quérel, A., Ryder, C. L., and Woodward, S.: Below-cloud scavenging of aerosol by rain: a review of numerical modelling approaches and sensitivity simulations with mineral dust in the Met Office's Unified Model, Atmos. Chem. Phys., 22, 11381–11407, https://doi.org/10.5194/acp-22-11381-2022, 2022. a
Juliano, T. W., Tornow, F., Fridlind, A. M., Ackerman, A. S., Elsaesser, G. S., Geerts, B., Lackner, C. P., Painemal, D., Silber, I., Ovchinnikov, M., Svensson, G., Tjernström, M., Wu, P., Baró Pérez, A., Bogenschutz, P., Chechin, D., Chandrakar, K. K., Chylik, J., Debolskiy, A., Fadeev, R., Gupta, A., Ickes, L., Karalis, M., Köhler, M., Kosović, B., Kuma, P., Li, W., Mortikov, E., Morrison, H., Neggers, R. A. J., Possner, A., Raatikainen, T., Raillard, L., Romakkaniemi, S., Schnierstein, N., Shima, S., Silin, N., Tolstykh, M., Vignon, É., Xue, L., Zhang, M., and Zheng, X.: The Cold-Air Outbreaks in the Marine Boundary Layer Experiment model-observation intercomparison project (COMBLE-MIP) – Part 1: Model specification, observational constraints, and preliminary findings, Atmos. Chem. Phys., 26, 13267–13302, https://doi.org/10.5194/acp-26-13267-2026, 2026. a
Karalis, M., Sotiropoulou, G., Abel, S. J., Bossioli, E., Georgakaki, P., Methymaki, G., Nenes, A., and Tombrou, M.: Effects of secondary ice processes on a stratocumulus to cumulus transition during a cold-air outbreak, Atmos. Res., 277, 106302, https://doi.org/10.1016/j.atmosres.2022.106302, 2022. a, b, c, d, e, f
King, L.: Using a small expansion chamber to characterise ice nucleation by high-latitude mineral dusts and volcanic ash, PhD, University of Leeds, https://etheses.whiterose.ac.uk/id/eprint/35595/ (last access: 30 January 2025), 2024. a
Kolstad, E. W. and Bracegirdle, T. J.: Marine cold-air outbreaks in the future: an assessment of IPCC AR4 model results for the Northern Hemisphere, Clim. Dynam., 30, 871–885, https://doi.org/10.1007/s00382-007-0331-0, 2008. a
Kolstad, E. W., Bracegirdle, T. J., and Seierstad, I. A.: Marine cold-air outbreaks in the North Atlantic: temporal distribution and associations with large-scale atmospheric circulation, Clim. Dynam., 33, 187–197, https://doi.org/10.1007/s00382-008-0431-5, 2009. a
Korolev, A. and Milbrandt, J.: How are mixed-phase clouds mixed?, Geophys. Res. Lett., 49, e2022GL099578, https://doi.org/10.1029/2022GL099578, 2022. a
Korolev, A., McFarquhar, G., Field, P. R., Franklin, C., Lawson, P., Wang, Z., Williams, E., Abel, S. J., Axisa, D., Borrmann, S., Crosier, J., Fugal, J., Krämer, M., Lohmann, U., Schlenczek, O., Schnaiter, M., and Wendisch, M.: Mixed-phase clouds: progress and challenges, Meteor. Mon., 58, 5.1–5.50, https://doi.org/10.1175/AMSMONOGRAPHS-D-17-0001.1, 2017. a
Lee, L. A., Carslaw, K. S., Pringle, K. J., Mann, G. W., and Spracklen, D. V.: Emulation of a complex global aerosol model to quantify sensitivity to uncertain parameters, Atmos. Chem. Phys., 11, 12253–12273, https://doi.org/10.5194/acp-11-12253-2011, 2011. a, b
Lee, L. A., Carslaw, K. S., Pringle, K. J., and Mann, G. W.: Mapping the uncertainty in global CCN using emulation, Atmos. Chem. Phys., 12, 9739–9751, https://doi.org/10.5194/acp-12-9739-2012, 2012. a
Lee, L. A., Pringle, K. J., Reddington, C. L., Mann, G. W., Stier, P., Spracklen, D. V., Pierce, J. R., and Carslaw, K. S.: The magnitude and causes of uncertainty in global model simulations of cloud condensation nuclei, Atmos. Chem. Phys., 13, 8879–8914, https://doi.org/10.5194/acp-13-8879-2013, 2013. a
Lee, L. A., Reddington, C. L., and Carslaw, K. S.: On the relationship between aerosol model uncertainty and radiative forcing uncertainty, P. Natl. Acad. Sci. USA, 113, 5820–5827, https://doi.org/10.1073/pnas.1507050113, 2016. a, b
Lee, S. S., Ha, K.-J., Manoj, M. G., Kamruzzaman, M., Kim, H., Utsumi, N., Zheng, Y., Kim, B.-G., Jung, C. H., Um, J., Guo, J., Choi, K. O., and Kim, G.-U.: Midlatitude mixed-phase stratocumulus clouds and their interactions with aerosols: how ice processes affect microphysical, dynamic, and thermodynamic development in those clouds and interactions?, Atmos. Chem. Phys., 21, 16843–16868, https://doi.org/10.5194/acp-21-16843-2021, 2021. a
Leisner, T., Pander, T., Handmann, P., and Kiselev, A.: Secondary ice processes upon heterogeneous freezing of cloud droplets, in: Proceedings of the 14th Conference on Cloud Physics and 14th Conference on Atmospheric Radiation, American Meteorological Society, Boston, MA, USA, https://ams.confex.com/ams/14CLOUD14ATRAD/webprogram/Paper250221.html (last access: 30 January 2025), 2014. a
Li, X.-Y., Wang, H., Chen, J., Endo, S., Kirschler, S., Voigt, C., Crosbie, E., Ziemba, L. D., Painemal, D., Cairns, B., Hair, J. W., Corral, A. F., Robinson, C., Dadashazar, H., Sorooshian, A., Chen, G., Ferrare, R. A., Kleb, M. M., Liu, H., Moore, R., Scarino, A. J., Shook, M. A., Shingler, T. J., Thornhill, K. L., Tornow, F., Xiao, H., and Zeng, X.: Large-eddy simulations of marine boundary layer clouds associated with cold-air outbreaks during the ACTIVATE campaign. Part II: Aerosol–meteorology–cloud interaction, J. Atmos. Sci., 80, 1025–1045, https://doi.org/10.1175/JAS-D-21-0324.1, 2023. a
Lock, A. P., Brown, A. R., Bush, M. R., Martin, G. M., and Smith, R. N. B.: A new boundary layer mixing scheme. Part I: Scheme description and single-column model tests, Mon. Weather Rev., 128, 3187–3199, https://doi.org/10.1175/1520-0493(2000)128<3187:ANBLMS>2.0.CO;2, 2000. a
Loeppky, J. L., Sacks, J., and Welch, W. J.: Choosing the sample size of a computer experiment: a practical guide, Technometrics, 51, 366–376, https://doi.org/10.1198/TECH.2009.08040, 2009. a
Mann, G. W., Carslaw, K. S., Spracklen, D. V., Ridley, D. A., Manktelow, P. T., Chipperfield, M. P., Pickering, S. J., and Johnson, C. E.: Description and evaluation of GLOMAP-mode: a modal global aerosol microphysics model for the UKCA composition-climate model, Geosci. Model Dev., 3, 519–551, https://doi.org/10.5194/gmd-3-519-2010, 2010. a
Manners, J., Edwards, J. M., Hill, P., and Thelen, J.-C.: SOCRATES Technical Guide Suite Of Community RAdiative Transfer codes based on Edwards and Slingo, Met Office, FitzRoy Rd, Exeter EX1 3PB, https://code.metoffice.gov.uk/trac/socrates (last access: 30 January 2025), 2023. a
Marshall, L., Johnson, J. S., Mann, G. W., Lee, L., Dhomse, S. S., Regayre, L., Yoshioka, M., Carslaw, K. S., and Schmidt, A.: Exploring how eruption source parameters affect volcanic radiative forcing using statistical emulation, J. Geophys. Res.-Atmos., 124, 964–985, https://doi.org/10.1029/2018JD028675, 2019. a
Mason, R. H., Si, M., Chou, C., Irish, V. E., Dickie, R., Elizondo, P., Wong, R., Brintnell, M., Elsasser, M., Lassar, W. M., Pierce, K. M., Leaitch, W. R., MacDonald, A. M., Platt, A., Toom-Sauntry, D., Sarda-Estève, R., Schiller, C. L., Suski, K. J., Hill, T. C. J., Abbatt, J. P. D., Huffman, J. A., DeMott, P. J., and Bertram, A. K.: Size-resolved measurements of ice-nucleating particles at six locations in North America and one in Europe, Atmos. Chem. Phys., 16, 1637–1651, https://doi.org/10.5194/acp-16-1637-2016, 2016. a
McCluskey, C. S., Ovadnevaite, J., Rinaldi, M., Atkinson, J., Belosi, F., Ceburnis, D., Marullo, S., Hill, T. C. J., Lohmann, U., Kanji, Z. A., O'Dowd, C., Kreidenweis, S. M., and DeMott, P. J.: Marine and terrestrial organic ice-nucleating particles in pristine marine to continentally influenced northeast Atlantic air masses, J. Geophys. Res.-Atmos., 123, 6196–6212, https://doi.org/10.1029/2017JD028033, 2018. a, b
McCluskey, C. S., Niu, Q., Hannay, C., Nusbaumer, J. M., Medeiros, B., McFarquhar, G. M., Chapman, W., Fowler, M. D., Stephens, B., Wang, D., Protat, A., and Mace, G. G.: Mixed phase aerosol-cloud interactions over the Southern Ocean, in: AGU Fall Meeting Abstracts, Vol. 2024 of AGU Fall Meeting Abstracts, A54C–01, https://studio.m-anage.com/agu/agu24/meetingapp.cgi/Paper/1647330 (last access: 30 January 2025), 2024. a
McCoy, I. L., Wood, R., and Fletcher, J. K.: Identifying meteorological controls on open and closed mesoscale cellular convection associated with marine cold air outbreaks, J. Geophys. Res.-Atmos., 122, 11678–11702, https://doi.org/10.1002/2017JD027031, 2017. a, b, c
Mitchell, J. F. B., Senior, C. A., and Ingram, W. J.: CO2 and climate: a missing feedback?, Nature, 341, 132–134, https://doi.org/10.1038/341132a0, 1989. a
MODIS Characterization Support Team (MCST): MODIS 1 km Calibrated Radiances Product, MODIS Adaptive Processing System, Goddard Space Flight Center, USA [data set], https://doi.org/10.5067/MODIS/MYD021KM.061, 2017. a
Morrison, H., van Lier-Walqui, M., Fridlind, A. M., Grabowski, W. W., Harrington, J. Y., Hoose, C., Korolev, A., Kumjian, M. R., Milbrandt, J. A., Pawlowska, H., Posselt, D. J., Prat, O. P., Reimel, K. J., Shima, S.-I., van Diedenhoven, B., and Xue, L.: Confronting the challenge of modeling cloud and precipitation microphysics, J. Adv. Model. Earth Sy., 12, e2019MS001689, https://doi.org/10.1029/2019MS001689, 2020. a
Murray, B. and the M-Phase Team: Ice production in northern hemisphere cold air-outbreak clouds: two contrasting aircraft campaigns, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-11598, https://doi.org/10.5194/egusphere-egu24-11598, 2024. a, b
Murray, B. J., O'Sullivan, D., Atkinson, J. D., and Webb, M. E.: Ice nucleation by particles immersed in supercooled cloud droplets, Chem. Soc. Rev., 41, 6519–6554, https://doi.org/10.1039/C2CS35200A, 2012. a
Murray, B. J., Carslaw, K. S., and Field, P. R.: Opinion: Cloud-phase climate feedback and the importance of ice-nucleating particles, Atmos. Chem. Phys., 21, 665–679, https://doi.org/10.5194/acp-21-665-2021, 2021. a, b
Murray-Watson, R. J., Gryspeerdt, E., and Goren, T.: Investigating the development of clouds within marine cold-air outbreaks, Atmos. Chem. Phys., 23, 9365–9383, https://doi.org/10.5194/acp-23-9365-2023, 2023. a
Niu, Q., McCluskey, C., and McFarquhar, G. M.: Marine boundary layer cloud condensation nuclei bias over the Southern Ocean: comparisons between the Community Atmosphere Model 6 and field observations, J. Geophys. Res.-Atmos., 130, e2024JD042734, https://doi.org/10.1029/2024JD042734, 2025. a
Oakley, J. and O'Hagan, A.: Bayesian inference for the uncertainty distribution of computer model outputs, Biometrika, 89, 769–784, https://doi.org/10.1093/biomet/89.4.769, 2002. a, b
O'Sullivan, D., Murray, B. J., Malkin, T. L., Whale, T. F., Umo, N. S., Atkinson, J. D., Price, H. C., Baustian, K. J., Browse, J., and Webb, M. E.: Ice nucleation by fertile soil dusts: relative importance of mineral and biogenic components, Atmos. Chem. Phys., 14, 1853–1867, https://doi.org/10.5194/acp-14-1853-2014, 2014. a
O'Hagan, A.: Bayesian analysis of computer code outputs: a tutorial, Reliability Engineering and System Safety, 91, 1290–1300, https://doi.org/10.1016/j.ress.2005.11.025, 2006. a, b
Paramonov, M., David, R. O., Kretzschmar, R., and Kanji, Z. A.: A laboratory investigation of the ice nucleation efficiency of three types of mineral and soil dust, Atmos. Chem. Phys., 18, 16515–16536, https://doi.org/10.5194/acp-18-16515-2018, 2018. a
Park, J. M., van den Heever, S. C., Igel, A. L., Grant, L. D., Johnson, J. S., Saleeby, S. M., Miller, S. D., and Reid, J. S.: Environmental controls on tropical sea breeze convection and resulting aerosol redistribution, J. Geophys. Res.-Atmos., 125, e2019JD031699, https://doi.org/10.1029/2019JD031699, 2020. a
Phillips, V. T. J., Yano, J.-I., and Khain, A.: Ice multiplication by breakup in ice–ice collisions. Part I: Theoretical formulation, J. Atmos. Sci., 74, 1705–1719, https://doi.org/10.1175/JAS-D-16-0224.1, 2017. a, b, c
Pinder, T. and Dodd, D.: GPJax: a Gaussian process framework in JAX, Journal of Open Source Software, 7, 4455, https://doi.org/10.21105/joss.04455, 2022. a
Porter, G. C. E., Sikora, S. N. F., Adams, M. P., Proske, U., Harrison, A. D., Tarn, M. D., Brooks, I. M., and Murray, B. J.: Resolving the size of ice-nucleating particles with a balloon deployable aerosol sampler: the SHARK, Atmos. Meas. Tech., 13, 2905–2921, https://doi.org/10.5194/amt-13-2905-2020, 2020. a, b
Porter, G. C. E., Adams, M. P., Brooks, I. M., Ickes, L., Karlsson, L., Leck, C., Salter, M. E., Schmale, J., Siegel, K., Sikora, S. N. F., Tarn, M. D., Vüllers, J., Wernli, H., Zieger, P., Zinke, J., and Murray, B. J.: Highly active ice-nucleating particles at the summer North Pole, J. Geophys. Res.-Atmos., 127, e2021JD036059, https://doi.org/10.1029/2021JD036059, 2022. a
Possner, A., Pfannkuch, K., and Ramadoss, V.: Cloud-Resolving ICON Simulations of Secondary Ice Production in Arctic Mixed-Phase Stratocumuli Observed during M-PACE, J. Atmos. Sci., 81, 417–434, https://doi.org/10.1175/JAS-D-23-0069.1, 2024. a
Prévost, L. M. C., Regayre, L. A., Johnson, J. S., McNeall, D., Milton, S., and Carslaw, K. S.: Detection of potential structural deficiencies in a global aerosol model using a perturbed parameter ensemble, Atmos. Chem. Phys., 26, 2487–2530, https://doi.org/10.5194/acp-26-2487-2026, 2026. a
Proske, U., Ferrachat, S., Neubauer, D., Staab, M., and Lohmann, U.: Assessing the potential for simplification in global climate model cloud microphysics, Atmos. Chem. Phys., 22, 4737–4762, https://doi.org/10.5194/acp-22-4737-2022, 2022. a
Proske, U., Ferrachat, S., Klampt, S., Abeling, M., and Lohmann, U.: Addressing complexity in global aerosol climate model cloud microphysics, J. Adv. Model. Earth Sy., 15, e2022MS003571, https://doi.org/10.1029/2022MS003571, 2023. a
Pruppacher, H. and Klett, J.: Microphysics of Clouds and Precipitation, Atmospheric and Oceanographic Sciences Library, Springer Netherlands, https://doi.org/10.1007/978-0-306-48100-0, 1996. a
Raif, E. N., Barr, S. L., Tarn, M. D., McQuaid, J. B., Daily, M. I., Abel, S. J., Barrett, P. A., Bower, K. N., Field, P. R., Carslaw, K. S., and Murray, B. J.: High ice-nucleating particle concentrations associated with Arctic haze in springtime cold-air outbreaks, Atmos. Chem. Phys., 24, 14045–14072, https://doi.org/10.5194/acp-24-14045-2024, 2024. a
Regayre, L. A., Pringle, K. J., Booth, B. B. B., Lee, L. A., Mann, G. W., Browse, J., Woodhouse, M. T., Rap, A., Reddington, C. L., and Carslaw, K. S.: Uncertainty in the magnitude of aerosol-cloud radiative forcing over recent decades, Geophys. Res. Lett., 41, 9040–9049, https://doi.org/10.1002/2014GL062029, 2014. a
Regayre, L. A., Pringle, K. J., Lee, L. A., Rap, A., Browse, J., Mann, G. W., Reddington, C. L., Carslaw, K. S., Booth, B. B. B., and Woodhouse, M. T.: The climatic importance of uncertainties in regional aerosol–cloud radiative forcings over recent decades, J. Climate, 28, 6589–6607, https://doi.org/10.1175/JCLI-D-15-0127.1, 2015. a
Regayre, L. A., Johnson, J. S., Yoshioka, M., Pringle, K. J., Sexton, D. M. H., Booth, B. B. B., Lee, L. A., Bellouin, N., and Carslaw, K. S.: Aerosol and physical atmosphere model parameters are both important sources of uncertainty in aerosol ERF, Atmos. Chem. Phys., 18, 9975–10006, https://doi.org/10.5194/acp-18-9975-2018, 2018. a
Regayre, L. A., Deaconu, L., Grosvenor, D. P., Sexton, D. M. H., Symonds, C., Langton, T., Watson-Paris, D., Mulcahy, J. P., Pringle, K. J., Richardson, M., Johnson, J. S., Rostron, J. W., Gordon, H., Lister, G., Stier, P., and Carslaw, K. S.: Identifying climate model structural inconsistencies allows for tight constraint of aerosol radiative forcing, Atmos. Chem. Phys., 23, 8749–8768, https://doi.org/10.5194/acp-23-8749-2023, 2023. a, b
Renfrew, I. A. and Moore, G. W. K.: An extreme cold-air outbreak over the Labrador Sea: roll vortices and air–sea interaction, Mon. Weather Rev., 127, 2379–2394, https://doi.org/10.1175/1520-0493(1999)127<2379:AECAOO>2.0.CO;2, 1999. a
Sanchez-Marroquin, A., Arnalds, O., Baustian-Dorsi, K. J., Browse, J., Dagsson-Waldhauserova, P., Harrison, A. D., Maters, E. C., Pringle, K. J., Vergara-Temprado, J., Burke, I. T., McQuaid, J. B., Carslaw, K. S., and Murray, B. J.: Iceland is an episodic source of atmospheric ice-nucleating particles relevant for mixed-phase clouds, Science Advances, 6, eaba8137, https://doi.org/10.1126/sciadv.aba8137, 2020. a, b
Sansom, R.: Demystifying the complex nature of stratocumulus clouds with machine learning, Weather, 76, 185–191, https://doi.org/10.1002/wea.4001, 2021. a
Sansom, R. W. N., Carslaw, K. S., Johnson, J. S., and Lee, L.: An emulator of stratocumulus cloud response to two cloud-controlling factors accounting for internal variability, J. Adv. Model. Earth Sy., 16, e2023MS004179, https://doi.org/10.1029/2023MS004179, 2024. a
Sansom, R. W. N., Johnson, J. S., Regayre, L. A., Lee, L. A., and Carslaw, K. S.: Strong control of the stratocumulus-to-cumulus transition time by aerosol: analysis of the joint roles of several cloud-controlling factors using Gaussian process emulation, Atmos. Chem. Phys., 26, 1713–1733, https://doi.org/10.5194/acp-26-1713-2026, 2026. a
Sherwood, S. C., Webb, M. J., Annan, J. D., Armour, K. C., Forster, P. M., Hargreaves, J. C., Hegerl, G., Klein, S. A., Marvel, K. D., Rohling, E. J., Watanabe, M., Andrews, T., Braconnot, P., Bretherton, C. S., Foster, G. L., Hausfather, Z., von der Heydt, A. S., Knutti, R., Mauritsen, T., Norris, J. R., Proistosescu, C., Rugenstein, M., Schmidt, G. A., Tokarska, K. B., and Zelinka, M. D.: An assessment of Earth's climate sensitivity using multiple lines of evidence, Rev. Geophys., 58, e2019RG000678, https://doi.org/10.1029/2019RG000678, 2020. a, b
Si, M., Evoy, E., Yun, J., Xi, Y., Hanna, S. J., Chivulescu, A., Rawlings, K., Veber, D., Platt, A., Kunkel, D., Hoor, P., Sharma, S., Leaitch, W. R., and Bertram, A. K.: Concentrations, composition, and sources of ice-nucleating particles in the Canadian High Arctic during spring 2016, Atmos. Chem. Phys., 19, 3007–3024, https://doi.org/10.5194/acp-19-3007-2019, 2019. a
Sotiropoulou, G., Sullivan, S., Savre, J., Lloyd, G., Lachlan-Cope, T., Ekman, A. M. L., and Nenes, A.: The impact of secondary ice production on Arctic stratocumulus, Atmos. Chem. Phys., 20, 1301–1316, https://doi.org/10.5194/acp-20-1301-2020, 2020. a, b
Steinke, I., Funk, R., Busse, J., Iturri, A., Kirchen, S., Leue, M., Möhler, O., Schwartz, T., Schnaiter, M., Sierau, B., Toprak, E., Ullrich, R., Ulrich, A., Hoose, C., and Leisner, T.: Ice nucleation activity of agricultural soil dust aerosols from Mongolia, Argentina, and Germany, J. Geophys. Res.-Atmos., 121, 13559–13576, https://doi.org/10.1002/2016JD025160, 2016. a
Steinke, I., Hiranuma, N., Funk, R., Höhler, K., Tüllmann, N., Umo, N. S., Weidler, P. G., Möhler, O., and Leisner, T.: Complex plant-derived organic aerosol as ice-nucleating particles – more than the sums of their parts?, Atmos. Chem. Phys., 20, 11387–11397, https://doi.org/10.5194/acp-20-11387-2020, 2020. a
Storelvmo, T., Tan, I., and Korolev, A. V.: Cloud phase changes induced by CO2 warming—a powerful yet poorly constrained cloud-climate feedback, Current Climate Change Reports, 1, 288–296, 2015. a
Takahashi, T., Nagao, Y., and Kushiyama, Y.: Possible high ice particle production during graupel–graupel collisions, J. Atmos. Sci., 52, 4523–4527, https://doi.org/10.1175/1520-0469(1995)052<4523:PHIPPD>2.0.CO;2, 1995. a, b
Tarn, M., Foster, P., McQuaid, J., Robinson, J., Clarke, S., Raif, E., Choularton, T., Gallagher, M., Bower, K., Field, P., and Murray, B.: Ice-nucleating particle measurements from the M-Phase 2022 flight campaign, Zenodo [data set], https://doi.org/10.5281/zenodo.14781199, 2025. a, b
Thompson, K. A.: The ice-nucleating activity of fertile soils and crop pathogens, PhD, University of Leeds, https://etheses.whiterose.ac.uk/id/eprint/34821/ (last access: 30 January 2025), 2024. a
Tornow, F., Ackerman, A. S., and Fridlind, A. M.: Preconditioning of overcast-to-broken cloud transitions by riming in marine cold air outbreaks, Atmos. Chem. Phys., 21, 12049–12067, https://doi.org/10.5194/acp-21-12049-2021, 2021. a, b, c, d
Twomey, S.: The influence of pollution on the shortwave albedo of clouds, J. Atmos. Sci., 34, 1149–1152, https://doi.org/10.1175/1520-0469(1977)034<1149:TIOPOT>2.0.CO;2, 1977. a
Usher, W., Herman, J., Whealton, C., Hadka, D., xantares, Rios, F., bernardoct, Mutel, C., and van Engelen, J.: SALib/SALib: Launch!, Zenodo [code], https://doi.org/10.5281/zenodo.160164, 2016. a
Vali, G.: Repeatability and randomness in heterogeneous freezing nucleation, Atmos. Chem. Phys., 8, 5017–5031, https://doi.org/10.5194/acp-8-5017-2008, 2008. a
Van Weverberg, K., Morcrette, C. J., and Boutle, I.: A bimodal diagnostic cloud fraction parameterization. Part II: Evaluation and resolution sensitivity, Mon. Weather Rev., 149, 859–878, https://doi.org/10.1175/MWR-D-20-0230.1, 2021a. a
Van Weverberg, K., Morcrette, C. J., Boutle, I., Furtado, K., and Field, P. R.: A bimodal diagnostic cloud fraction parameterization. Part I: Motivating analysis and scheme description, Mon. Weather Rev., 149, 841–857, https://doi.org/10.1175/MWR-D-20-0224.1, 2021b. a
Van Weverberg, K., Giangrande, S., Zhang, D., Morcrette, C. J., and Field, P. R.: On the role of macrophysics and microphysics in km-scale simulations of mixed-phase clouds during cold air outbreaks, J. Geophys. Res.-Atmos., 128, e2022JD037854, https://doi.org/10.1029/2022JD037854, 2023. a
Vergara-Temprado, J., Miltenberger, A. K., Furtado, K., Grosvenor, D. P., Shipway, B. J., Hill, A. A., Wilkinson, J. M., Field, P. R., Murray, B. J., and Carslaw, K. S.: Strong control of Southern Ocean cloud reflectivity by ice-nucleating particles, P. Natl. Acad. Sci. USA, 115, 2687–2692, https://doi.org/10.1073/pnas.1721627115, 2018. a, b
Walters, D., Boutle, I., Brooks, M., Melvin, T., Stratton, R., Vosper, S., Wells, H., Williams, K., Wood, N., Allen, T., Bushell, A., Copsey, D., Earnshaw, P., Edwards, J., Gross, M., Hardiman, S., Harris, C., Heming, J., Klingaman, N., Levine, R., Manners, J., Martin, G., Milton, S., Mittermaier, M., Morcrette, C., Riddick, T., Roberts, M., Sanchez, C., Selwood, P., Stirling, A., Smith, C., Suri, D., Tennant, W., Vidale, P. L., Wilkinson, J., Willett, M., Woolnough, S., and Xavier, P.: The Met Office Unified Model Global Atmosphere 6.0/6.1 and JULES Global Land 6.0/6.1 configurations, Geosci. Model Dev., 10, 1487–1520, https://doi.org/10.5194/gmd-10-1487-2017, 2017. a
Wegener, A.: Thermodynamik der Atmosphäre, https://books.google.co.uk/books?id=BMMxAAAAMAAJ (last access: 30 January 2025), 1911. a
Wellmann, C., Barrett, A. I., Johnson, J. S., Kunz, M., Vogel, B., Carslaw, K. S., and Hoose, C.: Using emulators to understand the sensitivity of deep convective clouds and hail to environmental conditions, J. Adv. Model. Earth Sy., 10, 3103–3122, https://doi.org/10.1029/2018MS001465, 2018. a
Wellmann, C., Barrett, A. I., Johnson, J. S., Kunz, M., Vogel, B., Carslaw, K. S., and Hoose, C.: Comparing the impact of environmental conditions and microphysics on the forecast uncertainty of deep convective clouds and hail, Atmos. Chem. Phys., 20, 2201–2219, https://doi.org/10.5194/acp-20-2201-2020, 2020. a
Welti, A., Bigg, E. K., DeMott, P. J., Gong, X., Hartmann, M., Harvey, M., Henning, S., Herenz, P., Hill, T. C. J., Hornblow, B., Leck, C., Löffler, M., McCluskey, C. S., Rauker, A. M., Schmale, J., Tatzelt, C., van Pinxteren, M., and Stratmann, F.: Ship-based measurements of ice nuclei concentrations over the Arctic, Atlantic, Pacific and Southern oceans, Atmos. Chem. Phys., 20, 15191–15206, https://doi.org/10.5194/acp-20-15191-2020, 2020. a
Willett, M., Brooks, M., Bushell, A., Earnshaw, P., Smith, S., Tomassini, L., Best, M., Boutle, I., Brooke, J., Edwards, J. M., Elvidge, A. D., Furtado, K., Hardacre, C., Hartley, A. J., Hewitt, A. J., Johnson, B., Lock, A., Malcolm, A., Mulcahy, J., Müller, E., Renfrew, I. A., Rumbold, H., Rooney, G. G., Sellar, A., Ujiie, M., van Niekerk, A., Wiltshire, A., and Whitall, M.: The Met Office Unified Model Global Atmosphere 8.0 and JULES Global Land 9.0 configurations, Geosci. Model Dev., 19, 1473–1517, https://doi.org/10.5194/gmd-19-1473-2026, 2026. a, b
Woodward, S., Sellar, A. A., Tang, Y., Stringer, M., Yool, A., Robertson, E., and Wiltshire, A.: The simulation of mineral dust in the United Kingdom Earth System Model UKESM1, Atmos. Chem. Phys., 22, 14503–14528, https://doi.org/10.5194/acp-22-14503-2022, 2022. a
Wu, P. and Ovchinnikov, M.: Cloud morphology evolution in Arctic cold-air outbreak: two cases during COMBLE period, J. Geophys. Res.-Atmos., 127, e2021JD035966, https://doi.org/10.1029/2021JD035966, 2022. a
Wu, P., Ovchinnikov, M., Xiao, H., Lackner, C. P., Geerts, B., Tornow, F., and Elsaesser, G.: Effect of ice number concentration on the evolution of boundary layer clouds during Arctic marine cold-air outbreaks, J. Geophys. Res.-Atmos., 130, e2024JD041282, https://doi.org/10.1029/2024JD041282, 2025. a
Young, G., Lachlan-Cope, T., O'Shea, S. J., Dearden, C., Listowski, C., Bower, K. N., Choularton, T. W., and Gallagher, M. W.: Radiative effects of secondary ice enhancement in coastal Antarctic clouds, Geophys. Res. Lett., 46, 2312–2321, https://doi.org/10.1029/2018GL080551, 2019. a
Zelinka, M. D., Myers, T. A., McCoy, D. T., Po-Chedley, S., Caldwell, P. M., Ceppi, P., Klein, S. A., and Taylor, K. E.: Causes of higher climate sensitivity in CMIP6 models, Geophys. Res. Lett., 47, e2019GL085782, https://doi.org/10.1029/2019GL085782, 2020. a
Short summary
Aerosol-cloud interactions and ice formation processes are key to modelling mixed-phase clouds in cold-air outbreaks. However, no studies have investigated the joint effects of these processes. Here, we used perturbed parameter ensembles and model emulators to show that these processes have strongly interacting effects on the properties of cold air outbreak clouds. Single sensitivity tests may therefore provide incomplete information about cloud-controlling factors.
Aerosol-cloud interactions and ice formation processes are key to modelling mixed-phase clouds...
Altmetrics
Final-revised paper
Preprint