Articles | Volume 16, issue 8
https://doi.org/10.5194/acp-16-4945-2016
© Author(s) 2016. This work is distributed under
the Creative Commons Attribution 3.0 License.
the Creative Commons Attribution 3.0 License.
https://doi.org/10.5194/acp-16-4945-2016
© Author(s) 2016. This work is distributed under
the Creative Commons Attribution 3.0 License.
the Creative Commons Attribution 3.0 License.
Research article
| 
21 Apr 2016
Research article |
| 21 Apr 2016
Comparing model and measured ice crystal concentrations in orographic clouds during the INUPIAQ campaign
Robert J. Farrington
CORRESPONDING AUTHOR
School of Earth, Atmospheric and Environmental Sciences, The University of Manchester, Manchester, UK
Paul J. Connolly
CORRESPONDING AUTHOR
School of Earth, Atmospheric and Environmental Sciences, The University of Manchester, Manchester, UK
Gary Lloyd
School of Earth, Atmospheric and Environmental Sciences, The University of Manchester, Manchester, UK
Keith N. Bower
School of Earth, Atmospheric and Environmental Sciences, The University of Manchester, Manchester, UK
Michael J. Flynn
School of Earth, Atmospheric and Environmental Sciences, The University of Manchester, Manchester, UK
Martin W. Gallagher
School of Earth, Atmospheric and Environmental Sciences, The University of Manchester, Manchester, UK
Paul R. Field
Met Office, Exeter, UK
Chris Dearden
School of Earth, Atmospheric and Environmental Sciences, The University of Manchester, Manchester, UK
Thomas W. Choularton
School of Earth, Atmospheric and Environmental Sciences, The University of Manchester, Manchester, UK
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Zhiqiang Cui, Alan Blyth, Yahui Huang, Gary Lloyd, Thomas Choularton, Keith Bower, Paul Field, Rachel Hawker, and Lindsay Bennett
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Secondary ice production (SIP) plays an important role in ice formation within mixed-phase clouds. We present a laboratory investigation of a potentially new SIP mechanism involving the collisions of supercooled water drops with ice particles. At impact, the supercooled water drop fragments form smaller secondary drops. Approximately 30 % of the secondary drops formed during the retraction phase of the supercooled water drop impact freeze over a temperature range of −4 °C to −12 °C.
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Bjorn Stevens, Sandrine Bony, David Farrell, Felix Ament, Alan Blyth, Christopher Fairall, Johannes Karstensen, Patricia K. Quinn, Sabrina Speich, Claudia Acquistapace, Franziska Aemisegger, Anna Lea Albright, Hugo Bellenger, Eberhard Bodenschatz, Kathy-Ann Caesar, Rebecca Chewitt-Lucas, Gijs de Boer, Julien Delanoë, Leif Denby, Florian Ewald, Benjamin Fildier, Marvin Forde, Geet George, Silke Gross, Martin Hagen, Andrea Hausold, Karen J. Heywood, Lutz Hirsch, Marek Jacob, Friedhelm Jansen, Stefan Kinne, Daniel Klocke, Tobias Kölling, Heike Konow, Marie Lothon, Wiebke Mohr, Ann Kristin Naumann, Louise Nuijens, Léa Olivier, Robert Pincus, Mira Pöhlker, Gilles Reverdin, Gregory Roberts, Sabrina Schnitt, Hauke Schulz, A. Pier Siebesma, Claudia Christine Stephan, Peter Sullivan, Ludovic Touzé-Peiffer, Jessica Vial, Raphaela Vogel, Paquita Zuidema, Nicola Alexander, Lyndon Alves, Sophian Arixi, Hamish Asmath, Gholamhossein Bagheri, Katharina Baier, Adriana Bailey, Dariusz Baranowski, Alexandre Baron, Sébastien Barrau, Paul A. Barrett, Frédéric Batier, Andreas Behrendt, Arne Bendinger, Florent Beucher, Sebastien Bigorre, Edmund Blades, Peter Blossey, Olivier Bock, Steven Böing, Pierre Bosser, Denis Bourras, Pascale Bouruet-Aubertot, Keith Bower, Pierre Branellec, Hubert Branger, Michal Brennek, Alan Brewer, Pierre-Etienne Brilouet, Björn Brügmann, Stefan A. Buehler, Elmo Burke, Ralph Burton, Radiance Calmer, Jean-Christophe Canonici, Xavier Carton, Gregory Cato Jr., Jude Andre Charles, Patrick Chazette, Yanxu Chen, Michal T. Chilinski, Thomas Choularton, Patrick Chuang, Shamal Clarke, Hugh Coe, Céline Cornet, Pierre Coutris, Fleur Couvreux, Susanne Crewell, Timothy Cronin, Zhiqiang Cui, Yannis Cuypers, Alton Daley, Gillian M. Damerell, Thibaut Dauhut, Hartwig Deneke, Jean-Philippe Desbios, Steffen Dörner, Sebastian Donner, Vincent Douet, Kyla Drushka, Marina Dütsch, André Ehrlich, Kerry Emanuel, Alexandros Emmanouilidis, Jean-Claude Etienne, Sheryl Etienne-Leblanc, Ghislain Faure, Graham Feingold, Luca Ferrero, Andreas Fix, Cyrille Flamant, Piotr Jacek Flatau, Gregory R. Foltz, Linda Forster, Iulian Furtuna, Alan Gadian, Joseph Galewsky, Martin Gallagher, Peter Gallimore, Cassandra Gaston, Chelle Gentemann, Nicolas Geyskens, Andreas Giez, John Gollop, Isabelle Gouirand, Christophe Gourbeyre, Dörte de Graaf, Geiske E. de Groot, Robert Grosz, Johannes Güttler, Manuel Gutleben, Kashawn Hall, George Harris, Kevin C. Helfer, Dean Henze, Calvert Herbert, Bruna Holanda, Antonio Ibanez-Landeta, Janet Intrieri, Suneil Iyer, Fabrice Julien, Heike Kalesse, Jan Kazil, Alexander Kellman, Abiel T. Kidane, Ulrike Kirchner, Marcus Klingebiel, Mareike Körner, Leslie Ann Kremper, Jan Kretzschmar, Ovid Krüger, Wojciech Kumala, Armin Kurz, Pierre L'Hégaret, Matthieu Labaste, Tom Lachlan-Cope, Arlene Laing, Peter Landschützer, Theresa Lang, Diego Lange, Ingo Lange, Clément Laplace, Gauke Lavik, Rémi Laxenaire, Caroline Le Bihan, Mason Leandro, Nathalie Lefevre, Marius Lena, Donald Lenschow, Qiang Li, Gary Lloyd, Sebastian Los, Niccolò Losi, Oscar Lovell, Christopher Luneau, Przemyslaw Makuch, Szymon Malinowski, Gaston Manta, Eleni Marinou, Nicholas Marsden, Sebastien Masson, Nicolas Maury, Bernhard Mayer, Margarette Mayers-Als, Christophe Mazel, Wayne McGeary, James C. McWilliams, Mario Mech, Melina Mehlmann, Agostino Niyonkuru Meroni, Theresa Mieslinger, Andreas Minikin, Peter Minnett, Gregor Möller, Yanmichel Morfa Avalos, Caroline Muller, Ionela Musat, Anna Napoli, Almuth Neuberger, Christophe Noisel, David Noone, Freja Nordsiek, Jakub L. Nowak, Lothar Oswald, Douglas J. Parker, Carolyn Peck, Renaud Person, Miriam Philippi, Albert Plueddemann, Christopher Pöhlker, Veronika Pörtge, Ulrich Pöschl, Lawrence Pologne, Michał Posyniak, Marc Prange, Estefanía Quiñones Meléndez, Jule Radtke, Karim Ramage, Jens Reimann, Lionel Renault, Klaus Reus, Ashford Reyes, Joachim Ribbe, Maximilian Ringel, Markus Ritschel, Cesar B. Rocha, Nicolas Rochetin, Johannes Röttenbacher, Callum Rollo, Haley Royer, Pauline Sadoulet, Leo Saffin, Sanola Sandiford, Irina Sandu, Michael Schäfer, Vera Schemann, Imke Schirmacher, Oliver Schlenczek, Jerome Schmidt, Marcel Schröder, Alfons Schwarzenboeck, Andrea Sealy, Christoph J. Senff, Ilya Serikov, Samkeyat Shohan, Elizabeth Siddle, Alexander Smirnov, Florian Späth, Branden Spooner, M. Katharina Stolla, Wojciech Szkółka, Simon P. de Szoeke, Stéphane Tarot, Eleni Tetoni, Elizabeth Thompson, Jim Thomson, Lorenzo Tomassini, Julien Totems, Alma Anna Ubele, Leonie Villiger, Jan von Arx, Thomas Wagner, Andi Walther, Ben Webber, Manfred Wendisch, Shanice Whitehall, Anton Wiltshire, Allison A. Wing, Martin Wirth, Jonathan Wiskandt, Kevin Wolf, Ludwig Worbes, Ethan Wright, Volker Wulfmeyer, Shanea Young, Chidong Zhang, Dongxiao Zhang, Florian Ziemen, Tobias Zinner, and Martin Zöger
Earth Syst. Sci. Data, 13, 4067–4119, https://doi.org/10.5194/essd-13-4067-2021, https://doi.org/10.5194/essd-13-4067-2021, 2021
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The EUREC4A field campaign, designed to test hypothesized mechanisms by which clouds respond to warming and benchmark next-generation Earth-system models, is presented. EUREC4A comprised roughly 5 weeks of measurements in the downstream winter trades of the North Atlantic – eastward and southeastward of Barbados. It was the first campaign that attempted to characterize the full range of processes and scales influencing trade wind clouds.
Ramiro Checa-Garcia, Yves Balkanski, Samuel Albani, Tommi Bergman, Ken Carslaw, Anne Cozic, Chris Dearden, Beatrice Marticorena, Martine Michou, Twan van Noije, Pierre Nabat, Fiona M. O'Connor, Dirk Olivié, Joseph M. Prospero, Philippe Le Sager, Michael Schulz, and Catherine Scott
Atmos. Chem. Phys., 21, 10295–10335, https://doi.org/10.5194/acp-21-10295-2021, https://doi.org/10.5194/acp-21-10295-2021, 2021
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Thousands of tons of dust are emitted into the atmosphere every year, producing important impacts on the Earth system. However, current global climate models are not yet able to reproduce dust emissions, transport and depositions with the desirable accuracy. Our study analyses five different Earth system models to report aspects to be improved to reproduce better available observations, increase the consistency between models and therefore decrease the current uncertainties.
Vidya Varma, Olaf Morgenstern, Kalli Furtado, Paul Field, and Jonny Williams
Atmos. Chem. Phys. Discuss., https://doi.org/10.5194/acp-2021-438, https://doi.org/10.5194/acp-2021-438, 2021
Revised manuscript not accepted
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We introduce a simple parametrisation whereby the immersion freezing temperature in the model is linked to the mineral dust distribution through a diagnostic function, thus invoking regional differences in the nucleation temperatures instead of the global default value of −10 °C. This provides a functionality to mimic the role of Ice Nucleating Particles in the atmosphere on influencing the short-wave radiation over the Southern Ocean region by impacting the cloud phase.
Rachel E. Hawker, Annette K. Miltenberger, Jonathan M. Wilkinson, Adrian A. Hill, Ben J. Shipway, Zhiqiang Cui, Richard J. Cotton, Ken S. Carslaw, Paul R. Field, and Benjamin J. Murray
Atmos. Chem. Phys., 21, 5439–5461, https://doi.org/10.5194/acp-21-5439-2021, https://doi.org/10.5194/acp-21-5439-2021, 2021
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The impact of aerosols on clouds is a large source of uncertainty for future climate projections. Our results show that the radiative properties of a complex convective cloud field in the Saharan outflow region are sensitive to the temperature dependence of ice-nucleating particle concentrations. This means that differences in the aerosol source or composition, for the same aerosol size distribution, can cause differences in the outgoing radiation from regions dominated by tropical convection.
Annette K. Miltenberger and Paul R. Field
Atmos. Chem. Phys., 21, 3627–3642, https://doi.org/10.5194/acp-21-3627-2021, https://doi.org/10.5194/acp-21-3627-2021, 2021
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The formation of ice in clouds is an important processes in mixed-phase and ice-phase clouds. However, the representation of ice formation in numerical models is highly uncertain. In the last decade, several new parameterizations for heterogeneous freezing have been proposed. Here, we investigate the impact of the parameterization choice on the representation of the convective cloud field and compare the impact to that of initial condition uncertainty.
Sebastian O'Shea, Jonathan Crosier, James Dorsey, Louis Gallagher, Waldemar Schledewitz, Keith Bower, Oliver Schlenczek, Stephan Borrmann, Richard Cotton, Christopher Westbrook, and Zbigniew Ulanowski
Atmos. Meas. Tech., 14, 1917–1939, https://doi.org/10.5194/amt-14-1917-2021, https://doi.org/10.5194/amt-14-1917-2021, 2021
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The number, shape, and size of ice crystals in clouds are important properties that influence the Earth's radiation budget, cloud evolution, and precipitation formation. This work suggests that one of the most widely used methods for in situ measurements of these properties has significant uncertainties and biases. We suggest methods that dramatically improve these measurements, which can be applied to past and future datasets from these instruments.
Fanny Peers, Peter Francis, Steven J. Abel, Paul A. Barrett, Keith N. Bower, Michael I. Cotterell, Ian Crawford, Nicholas W. Davies, Cathryn Fox, Stuart Fox, Justin M. Langridge, Kerry G. Meyer, Steven E. Platnick, Kate Szpek, and Jim M. Haywood
Atmos. Chem. Phys., 21, 3235–3254, https://doi.org/10.5194/acp-21-3235-2021, https://doi.org/10.5194/acp-21-3235-2021, 2021
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Satellite observations at high temporal resolution are a valuable asset to monitor the transport of biomass burning plumes and the cloud diurnal cycle in the South Atlantic, but they need to be validated. Cloud and above-cloud aerosol properties retrieved from SEVIRI are compared against MODIS and measurements from the CLARIFY-2017 campaign. While some systematic differences are observed between SEVIRI and MODIS, the overall agreement in the cloud and aerosol properties is very satisfactory.
Jim M. Haywood, Steven J. Abel, Paul A. Barrett, Nicolas Bellouin, Alan Blyth, Keith N. Bower, Melissa Brooks, Ken Carslaw, Haochi Che, Hugh Coe, Michael I. Cotterell, Ian Crawford, Zhiqiang Cui, Nicholas Davies, Beth Dingley, Paul Field, Paola Formenti, Hamish Gordon, Martin de Graaf, Ross Herbert, Ben Johnson, Anthony C. Jones, Justin M. Langridge, Florent Malavelle, Daniel G. Partridge, Fanny Peers, Jens Redemann, Philip Stier, Kate Szpek, Jonathan W. Taylor, Duncan Watson-Parris, Robert Wood, Huihui Wu, and Paquita Zuidema
Atmos. Chem. Phys., 21, 1049–1084, https://doi.org/10.5194/acp-21-1049-2021, https://doi.org/10.5194/acp-21-1049-2021, 2021
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Every year, the seasonal cycle of biomass burning from agricultural practices in Africa creates a huge plume of smoke that travels many thousands of kilometres over the Atlantic Ocean. This study provides an overview of a measurement campaign called the cloud–aerosol–radiation interaction and forcing for year 2017 (CLARIFY-2017) and documents the rationale, deployment strategy, observations, and key results from the campaign which utilized the heavily equipped FAAM atmospheric research aircraft.
Patrick A. Barker, Grant Allen, Martin Gallagher, Joseph R. Pitt, Rebecca E. Fisher, Thomas Bannan, Euan G. Nisbet, Stéphane J.-B. Bauguitte, Dominika Pasternak, Samuel Cliff, Marina B. Schimpf, Archit Mehra, Keith N. Bower, James D. Lee, Hugh Coe, and Carl J. Percival
Atmos. Chem. Phys., 20, 15443–15459, https://doi.org/10.5194/acp-20-15443-2020, https://doi.org/10.5194/acp-20-15443-2020, 2020
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Africa is estimated to account for approximately 52 % of global biomass burning (BB) carbon emissions. Despite this, there has been little previous in situ study of African BB emissions. This work presents BB emission factors for various atmospheric trace gases sampled from an aircraft in two distinct areas of Africa (Senegal and Uganda). Intracontinental variability in biomass burning methane emission is identified, which is attributed to difference in the specific fuel mixtures burnt.
Douglas Morrison, Ian Crawford, Nicholas Marsden, Michael Flynn, Katie Read, Luis Neves, Virginia Foot, Paul Kaye, Warren Stanley, Hugh Coe, David Topping, and Martin Gallagher
Atmos. Chem. Phys., 20, 14473–14490, https://doi.org/10.5194/acp-20-14473-2020, https://doi.org/10.5194/acp-20-14473-2020, 2020
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We provide conservative estimates of the concentrations of bacteria within transatlantic dust clouds, originating from the African continent. We observe significant seasonal differences in the overall concentrations of particles but no seasonal variation in the ratio between bacteria and dust. With bacteria contributing to ice formation at warmer temperatures than dust, our observations should improve the accuracy of climate models.
Richard J. Bantges, Helen E. Brindley, Jonathan E. Murray, Alan E. Last, Jacqueline E. Russell, Cathryn Fox, Stuart Fox, Chawn Harlow, Sebastian J. O'Shea, Keith N. Bower, Bryan A. Baum, Ping Yang, Hilke Oetjen, and Juliet C. Pickering
Atmos. Chem. Phys., 20, 12889–12903, https://doi.org/10.5194/acp-20-12889-2020, https://doi.org/10.5194/acp-20-12889-2020, 2020
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Understanding how ice clouds influence the Earth's energy balance remains a key challenge for predicting the future climate. These clouds are ubiquitous and are composed of ice crystals that have complex shapes that are incredibly difficult to model. This work exploits new measurements of the Earth's emitted thermal energy made from instruments flown on board an aircraft to test how well the latest ice cloud models can represent these clouds. Results indicate further developments are required.
Jessica Slater, Juha Tonttila, Gordon McFiggans, Paul Connolly, Sami Romakkaniemi, Thomas Kühn, and Hugh Coe
Atmos. Chem. Phys., 20, 11893–11906, https://doi.org/10.5194/acp-20-11893-2020, https://doi.org/10.5194/acp-20-11893-2020, 2020
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The feedback effect between aerosol particles, radiation and meteorology reduces turbulent motion and results in increased surface aerosol concentrations during Beijing haze. Observational analysis and regional modelling studies have examined the feedback effect but these studies are limited. In this work, we set up a high-resolution model for the Beijing environment to examine the sensitivity of the aerosol feedback effect to initial meteorological conditions and aerosol loading.
Hamish Gordon, Paul R. Field, Steven J. Abel, Paul Barrett, Keith Bower, Ian Crawford, Zhiqiang Cui, Daniel P. Grosvenor, Adrian A. Hill, Jonathan Taylor, Jonathan Wilkinson, Huihui Wu, and Ken S. Carslaw
Atmos. Chem. Phys., 20, 10997–11024, https://doi.org/10.5194/acp-20-10997-2020, https://doi.org/10.5194/acp-20-10997-2020, 2020
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The Met Office's Unified Model is widely used both for weather forecasting and climate prediction. We present the first version of the model in which both aerosol and cloud particle mass and number concentrations are allowed to evolve separately and independently, which is important for studying how aerosols affect weather and climate. We test the model against aircraft observations near Ascension Island in the Atlantic, focusing on how aerosols can "activate" to become cloud droplets.
Annette K. Miltenberger, Paul R. Field, Adrian H. Hill, and Andrew J. Heymsfield
Atmos. Chem. Phys., 20, 7979–8001, https://doi.org/10.5194/acp-20-7979-2020, https://doi.org/10.5194/acp-20-7979-2020, 2020
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Orographic wave clouds offer a natural laboratory to investigate cloud microphysical processes and their representation in atmospheric models. They impact the larger-scale flow by a vertical redistribution of moisture and aerosol. We use detailed observations from the ICE-L campaign to evaluate the representation of these clouds in a state-of-the-art numerical weather prediction model and explore the impact of environmental conditions on the vertical redistribution of moisture.
Vidya Varma, Olaf Morgenstern, Paul Field, Kalli Furtado, Jonny Williams, and Patrick Hyder
Atmos. Chem. Phys., 20, 7741–7751, https://doi.org/10.5194/acp-20-7741-2020, https://doi.org/10.5194/acp-20-7741-2020, 2020
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The present generation of global climate models has an insufficiently reflected short-wave radiation, especially over the Southern Ocean. This leads to an excessive heating of the ocean surface in the model, creating sea surface temperature biases and subsequent problems with atmospheric dynamics. Misrepresentation of clouds could be attributed to this radiation bias; we try to address this issue by slowing the growth rate of ice crystals and improving the supercooled liquid clouds in the model.
Kalli Furtado, Paul Field, Yali Luo, Tianjun Zhou, and Adrian Hill
Atmos. Chem. Phys., 20, 5093–5110, https://doi.org/10.5194/acp-20-5093-2020, https://doi.org/10.5194/acp-20-5093-2020, 2020
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By combining observations with simulations from a weather forecasting model, new insights are obtained into extreme rainfall processes. We use a model which includes the effects of aerosols on clouds in a fully consistent way. This greater complexity improves realism but raises the computational cost. We address the cost–benefit relationship of this and show that cloud–aerosol interactions have important, measurable benefits for simulating climate extremes.
Daniel T. McCoy, Paul Field, Hamish Gordon, Gregory S. Elsaesser, and Daniel P. Grosvenor
Atmos. Chem. Phys., 20, 4085–4103, https://doi.org/10.5194/acp-20-4085-2020, https://doi.org/10.5194/acp-20-4085-2020, 2020
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Incomplete understanding of how aerosol affects clouds degrades our ability to predict future climate. In particular, it is unclear how aerosol affects the lifetime of clouds. Does it increase or decrease it? This confusion is partially because causality flows from aerosol to clouds and clouds to aerosol, and it is hard to tell what is happening in observations. Here, we use simulations to tell us about how clouds affect aerosol and use this to interpret observations, showing increased lifetime.
Steven J. Abel, Paul A. Barrett, Paquita Zuidema, Jianhao Zhang, Matt Christensen, Fanny Peers, Jonathan W. Taylor, Ian Crawford, Keith N. Bower, and Michael Flynn
Atmos. Chem. Phys., 20, 4059–4084, https://doi.org/10.5194/acp-20-4059-2020, https://doi.org/10.5194/acp-20-4059-2020, 2020
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In situ measurements of a free-tropospheric (FT) biomass burning aerosol plume in contact with the boundary layer inversion overriding a pocket of open cells (POC) and surrounding stratiform cloud are presented. The data highlight the contrasting thermodynamic, aerosol and cloud properties in the two cloud regimes and further demonstrate that the cloud regime plays a key role in regulating the flow of FT aerosols into the boundary layer, which has implications for the aerosol indirect effect.
Gary Lloyd, Thomas Choularton, Keith Bower, Jonathan Crosier, Martin Gallagher, Michael Flynn, James Dorsey, Dantong Liu, Jonathan W. Taylor, Oliver Schlenczek, Jacob Fugal, Stephan Borrmann, Richard Cotton, Paul Field, and Alan Blyth
Atmos. Chem. Phys., 20, 3895–3904, https://doi.org/10.5194/acp-20-3895-2020, https://doi.org/10.5194/acp-20-3895-2020, 2020
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Measurements of liquid and ice cloud particles were made using an aircraft to penetrate fresh growing convective clouds in the tropical Atlantic. We found small ice particles at surprisingly high temperatures just below freezing. At colder temperatures secondary ice processes rapidly generated high concentrations of ice crystals.
Adil Shah, Joseph R. Pitt, Hugo Ricketts, J. Brian Leen, Paul I. Williams, Khristopher Kabbabe, Martin W. Gallagher, and Grant Allen
Atmos. Meas. Tech., 13, 1467–1484, https://doi.org/10.5194/amt-13-1467-2020, https://doi.org/10.5194/amt-13-1467-2020, 2020
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Methane is a potent greenhouse gas, with large flux uncertainties from facility-scale sources, such as natural gas extraction infrastructure. A recently developed flux quantification method was successfully tested by flying an unmanned aerial vehicle (UAV) downwind of 22 controlled atmospheric methane releases. The UAVs were used to derive high-precision atmospheric methane measurements. The UAV methodology was successful in both detecting the release and providing a rough flux estimate.
Kathryn Fowler, Paul Connolly, and David Topping
Atmos. Chem. Phys., 20, 683–698, https://doi.org/10.5194/acp-20-683-2020, https://doi.org/10.5194/acp-20-683-2020, 2020
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Observations of low–temperature cirrus clouds have found unexpectedly low ice crystal numbers and high supersaturations, suggesting an incomplete understanding of the freezing mechanisms under these conditions. The existence of viscous organic aerosol has offered alternative ice nucleation pathways, which have been observed in laboratory studies. We have developed the first cloud parcel model to investigate the effect of viscosity on ice nucleation.
George Spill, Philip Stier, Paul R. Field, and Guy Dagan
Atmos. Chem. Phys., 19, 13507–13517, https://doi.org/10.5194/acp-19-13507-2019, https://doi.org/10.5194/acp-19-13507-2019, 2019
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Shallow convective clouds are among the most common and least understood clouds in the atmosphere. Here we present simulations of realistic, shallow cloud fields in a large domain, in contrast to typical idealised simulations, and find that in these simulations the response to aerosol perturbations is different.
Joseph R. Pitt, Grant Allen, Stéphane J.-B. Bauguitte, Martin W. Gallagher, James D. Lee, Will Drysdale, Beth Nelson, Alistair J. Manning, and Paul I. Palmer
Atmos. Chem. Phys., 19, 8931–8945, https://doi.org/10.5194/acp-19-8931-2019, https://doi.org/10.5194/acp-19-8931-2019, 2019
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This paper presents a new method to assess inventory estimates of greenhouse gas and air pollutant emissions for large cities and their surrounding regions. A case study using data sampled by a research aircraft around London was used to test the method. We found that the UK national inventory agrees with our observations for CO but needed lower emissions for CH4 to agree with the measured data. Repeated studies could help determine how these emissions vary on different timescales.
Jonathan W. Taylor, Sophie L. Haslett, Keith Bower, Michael Flynn, Ian Crawford, James Dorsey, Tom Choularton, Paul J. Connolly, Valerian Hahn, Christiane Voigt, Daniel Sauer, Régis Dupuy, Joel Brito, Alfons Schwarzenboeck, Thierry Bourriane, Cyrielle Denjean, Phil Rosenberg, Cyrille Flamant, James D. Lee, Adam R. Vaughan, Peter G. Hill, Barbara Brooks, Valéry Catoire, Peter Knippertz, and Hugh Coe
Atmos. Chem. Phys., 19, 8503–8522, https://doi.org/10.5194/acp-19-8503-2019, https://doi.org/10.5194/acp-19-8503-2019, 2019
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Low-level clouds cover a wide area of southern West Africa (SWA) and play an important role in the region's climate, reflecting sunlight away from the surface. We performed aircraft measurements of aerosols and clouds over SWA during the 2016 summer monsoon and found pollution, and polluted clouds, across the whole region. Smoke from biomass burning in Central Africa is transported to West Africa, causing a polluted background which limits the effect of local pollution on cloud properties.
Stuart Fox, Jana Mendrok, Patrick Eriksson, Robin Ekelund, Sebastian J. O'Shea, Keith N. Bower, Anthony J. Baran, R. Chawn Harlow, and Juliet C. Pickering
Atmos. Meas. Tech., 12, 1599–1617, https://doi.org/10.5194/amt-12-1599-2019, https://doi.org/10.5194/amt-12-1599-2019, 2019
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Airborne observations of ice clouds are used to validate radiative transfer simulations using a state-of-the-art database of cloud ice optical properties. Simulations at these wavelengths are required to make use of future satellite instruments such as the Ice Cloud Imager. We show that they can generally reproduce observed cloud signals, but for a given total ice mass there is considerable sensitivity to the cloud microphysics, including the particle shape and distribution of ice mass.
Elizabeth Forde, Martin Gallagher, Virginia Foot, Roland Sarda-Esteve, Ian Crawford, Paul Kaye, Warren Stanley, and David Topping
Atmos. Chem. Phys., 19, 1665–1684, https://doi.org/10.5194/acp-19-1665-2019, https://doi.org/10.5194/acp-19-1665-2019, 2019
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The abundance and diversity of airborne biological particles in different environments remains poorly constrained. Measurements of such particles were conducted at four sites in the United Kingdom, using real-time fluorescence instrumentation. Using local land cover types, sources of suspected particle types were identified and compared. Most sites exhibited a wet-discharged fungal spore dominance, with the exception of one site, which was inferred to be influenced by a local dairy farm.
Daniel T. McCoy, Paul R. Field, Gregory S. Elsaesser, Alejandro Bodas-Salcedo, Brian H. Kahn, Mark D. Zelinka, Chihiro Kodama, Thorsten Mauritsen, Benoit Vanniere, Malcolm Roberts, Pier L. Vidale, David Saint-Martin, Aurore Voldoire, Rein Haarsma, Adrian Hill, Ben Shipway, and Jonathan Wilkinson
Atmos. Chem. Phys., 19, 1147–1172, https://doi.org/10.5194/acp-19-1147-2019, https://doi.org/10.5194/acp-19-1147-2019, 2019
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The largest single source of uncertainty in the climate sensitivity predicted by global climate models is how much low-altitude clouds change as the climate warms. Models predict that the amount of liquid within and the brightness of low-altitude clouds increase in the extratropics with warming. We show that increased fluxes of moisture into extratropical storms in the midlatitudes explain the majority of the observed trend and the modeled increase in liquid water within these storms.
Franco Marenco, Claire Ryder, Victor Estellés, Debbie O'Sullivan, Jennifer Brooke, Luke Orgill, Gary Lloyd, and Martin Gallagher
Atmos. Chem. Phys., 18, 17655–17668, https://doi.org/10.5194/acp-18-17655-2018, https://doi.org/10.5194/acp-18-17655-2018, 2018
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The AER-D airborne campaign characterised Saharan dust in the eastern Atlantic. We report an instance of unusual vertical structure of the Saharan Air Layer during an intense event, showing a large radiative impact and correlated with anomalous lightning activity. Moreover, we report a significant presence of giant dust particles. This is important because most models would miss the giant particles. Our findings may change the way we represent dust transport and deposition in the Atlantic.
Claire L. Ryder, Franco Marenco, Jennifer K. Brooke, Victor Estelles, Richard Cotton, Paola Formenti, James B. McQuaid, Hannah C. Price, Dantong Liu, Patrick Ausset, Phil D. Rosenberg, Jonathan W. Taylor, Tom Choularton, Keith Bower, Hugh Coe, Martin Gallagher, Jonathan Crosier, Gary Lloyd, Eleanor J. Highwood, and Benjamin J. Murray
Atmos. Chem. Phys., 18, 17225–17257, https://doi.org/10.5194/acp-18-17225-2018, https://doi.org/10.5194/acp-18-17225-2018, 2018
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Every year, millions of tons of Saharan dust particles are carried across the Atlantic by the wind, where they can affect weather patterns and climate. Their sizes span orders of magnitude, but the largest (over 10 microns – around the width of a human hair) are difficult to measure and few observations exist. Here we show new aircraft observations of large dust particles, finding more than we would expect, and we quantify their properties which allow them to interact with atmospheric radiation.
Gary Lloyd, Thomas W. Choularton, Keith N. Bower, Martin W. Gallagher, Jonathan Crosier, Sebastian O'Shea, Steven J. Abel, Stuart Fox, Richard Cotton, and Ian A. Boutle
Atmos. Chem. Phys., 18, 17191–17206, https://doi.org/10.5194/acp-18-17191-2018, https://doi.org/10.5194/acp-18-17191-2018, 2018
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The work deals with cold weather outbreaks at high latitudes that often bring severe weather such as heavy snow, lightning and high winds but are poorly forecast by weather models. Here we made measurements of these events and the clouds associated with them using a research aircraft. We found that the properties of these clouds were often very different to what the models predicted, and these results can potentially be used to bring significant improvement to the forecasting of these events.
Simon Ruske, David O. Topping, Virginia E. Foot, Andrew P. Morse, and Martin W. Gallagher
Atmos. Meas. Tech., 11, 6203–6230, https://doi.org/10.5194/amt-11-6203-2018, https://doi.org/10.5194/amt-11-6203-2018, 2018
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Pollen, bacteria and fungal spores are common in the environment, can have very important implications for public health and may influence the weather. Biological sensors potentially could be used to monitor quantities of these types of particles. However, it is important to transform the measurements from these instruments into counts of these biological particles. The paper tests a variety of approaches for achieving this aim on data collected in a laboratory.
Hamish Gordon, Paul R. Field, Steven J. Abel, Mohit Dalvi, Daniel P. Grosvenor, Adrian A. Hill, Ben T. Johnson, Annette K. Miltenberger, Masaru Yoshioka, and Ken S. Carslaw
Atmos. Chem. Phys., 18, 15261–15289, https://doi.org/10.5194/acp-18-15261-2018, https://doi.org/10.5194/acp-18-15261-2018, 2018
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Smoke from African fires is frequently transported across the Atlantic Ocean, where it interacts with clouds. We simulate the interaction of the smoke with the clouds, and the consequences of this for the solar radiation the clouds reflect. The simulations use a new regional configuration of the UK Met Office climate model. Our simulations indicate that the properties of the clouds, in particular their height and reflectivity, and the fractional cloud cover, are strongly affected by the smoke.
Christopher Dearden, Adrian Hill, Hugh Coe, and Tom Choularton
Atmos. Chem. Phys., 18, 14253–14269, https://doi.org/10.5194/acp-18-14253-2018, https://doi.org/10.5194/acp-18-14253-2018, 2018
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We perform computer simulations of the life cycle of low-lying clouds over southern West Africa during the monsoon season. Such clouds tend not to produce much precipitation, but they do affect the regional climate by modifying the amount of sunlight reaching the surface. The aim of this work is to understand the factors that influence the growth and break-up of these clouds. We show that the number of water droplets contained within the clouds affects how quickly they dissipate.
Paul I. Palmer, Simon O'Doherty, Grant Allen, Keith Bower, Hartmut Bösch, Martyn P. Chipperfield, Sarah Connors, Sandip Dhomse, Liang Feng, Douglas P. Finch, Martin W. Gallagher, Emanuel Gloor, Siegfried Gonzi, Neil R. P. Harris, Carole Helfter, Neil Humpage, Brian Kerridge, Diane Knappett, Roderic L. Jones, Michael Le Breton, Mark F. Lunt, Alistair J. Manning, Stephan Matthiesen, Jennifer B. A. Muller, Neil Mullinger, Eiko Nemitz, Sebastian O'Shea, Robert J. Parker, Carl J. Percival, Joseph Pitt, Stuart N. Riddick, Matthew Rigby, Harjinder Sembhi, Richard Siddans, Robert L. Skelton, Paul Smith, Hannah Sonderfeld, Kieran Stanley, Ann R. Stavert, Angelina Wenger, Emily White, Christopher Wilson, and Dickon Young
Atmos. Chem. Phys., 18, 11753–11777, https://doi.org/10.5194/acp-18-11753-2018, https://doi.org/10.5194/acp-18-11753-2018, 2018
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This paper provides an overview of the Greenhouse gAs Uk and Global Emissions (GAUGE) experiment. GAUGE was designed to quantify nationwide GHG emissions of the UK, bringing together measurements and atmospheric transport models. This novel experiment is the first of its kind. We anticipate it will inform the blueprint for countries that are building a measurement infrastructure in preparation for global stocktakes, which are a key part of the Paris Agreement.
Matthew Crooks, Paul Connolly, and Gordon McFiggans
Geosci. Model Dev., 11, 3261–3278, https://doi.org/10.5194/gmd-11-3261-2018, https://doi.org/10.5194/gmd-11-3261-2018, 2018
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Clouds form when water condenses onto particles in the atmosphere and the size and chemical composition of these particles can have a large influence over how much water condenses and the subsequent formation of cloud. Additional gases exist in the atmosphere that can condense onto the aerosol particles and change their composition. We present a fast and efficient method of calculating the effect of atmospheric gases on the formation of cloud that can be used in climate and weather models.
Robin G. Stevens, Katharina Loewe, Christopher Dearden, Antonios Dimitrelos, Anna Possner, Gesa K. Eirund, Tomi Raatikainen, Adrian A. Hill, Benjamin J. Shipway, Jonathan Wilkinson, Sami Romakkaniemi, Juha Tonttila, Ari Laaksonen, Hannele Korhonen, Paul Connolly, Ulrike Lohmann, Corinna Hoose, Annica M. L. Ekman, Ken S. Carslaw, and Paul R. Field
Atmos. Chem. Phys., 18, 11041–11071, https://doi.org/10.5194/acp-18-11041-2018, https://doi.org/10.5194/acp-18-11041-2018, 2018
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We perform a model intercomparison of summertime high Arctic clouds. Observed concentrations of aerosol particles necessary for cloud formation fell to extremely low values, coincident with a transition from cloudy to nearly cloud-free conditions. Previous analyses have suggested that at these low concentrations, the radiative properties of the clouds are determined primarily by these particle concentrations. The model results strongly support this hypothesis.
Annette K. Miltenberger, Paul R. Field, Adrian A. Hill, Ben J. Shipway, and Jonathan M. Wilkinson
Atmos. Chem. Phys., 18, 10593–10613, https://doi.org/10.5194/acp-18-10593-2018, https://doi.org/10.5194/acp-18-10593-2018, 2018
Konrad Deetz, Heike Vogel, Peter Knippertz, Bianca Adler, Jonathan Taylor, Hugh Coe, Keith Bower, Sophie Haslett, Michael Flynn, James Dorsey, Ian Crawford, Christoph Kottmeier, and Bernhard Vogel
Atmos. Chem. Phys., 18, 9767–9788, https://doi.org/10.5194/acp-18-9767-2018, https://doi.org/10.5194/acp-18-9767-2018, 2018
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Highly resolved process study simulations for 2–3 July are conducted with COSMO-ART to assess the aerosol direct and indirect effect on meteorological conditions over southern West Africa. The meteorological phenomena of Atlantic inflow and stratus-to-cumulus transition are identified as highly susceptible to the aerosol direct effect, leading to a spatial shift of the Atlantic inflow front and a temporal shift of the stratus-to-cumulus transition with changes in the aerosol amount.
Wiebke Frey, Dawei Hu, James Dorsey, M. Rami Alfarra, Aki Pajunoja, Annele Virtanen, Paul Connolly, and Gordon McFiggans
Atmos. Chem. Phys., 18, 9393–9409, https://doi.org/10.5194/acp-18-9393-2018, https://doi.org/10.5194/acp-18-9393-2018, 2018
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The coupled system of the Manchester Aerosol Chamber and Manchester Ice Cloud Chamber was used to study the ice-forming abilities of secondary
organic aerosol particles under mixed-phase cloud conditions. Given the vast abundance of secondary organic particles in the atmosphere, they
might present an important contribution to ice-nucleating particles. However, we find that in the studied temperature range (20 to 28 °C)
the secondary organic particles do not nucleate ice particles.
Emma L. Simpson, Paul J. Connolly, and Gordon McFiggans
Atmos. Chem. Phys., 18, 7237–7250, https://doi.org/10.5194/acp-18-7237-2018, https://doi.org/10.5194/acp-18-7237-2018, 2018
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This study explores the process of ice formation in clouds by conducting computer model simulations and laboratory experiments in a cloud chamber. We show that the formation of ice in clouds can be limited by the presence of atmospheric aerosol particles and that further research is required to identify the requirements for freezing, e.g. minimum mass of water, in order to accurately calculate ice formation and thus improve climate and weather prediction.
Daniel T. McCoy, Paul R. Field, Anja Schmidt, Daniel P. Grosvenor, Frida A.-M. Bender, Ben J. Shipway, Adrian A. Hill, Jonathan M. Wilkinson, and Gregory S. Elsaesser
Atmos. Chem. Phys., 18, 5821–5846, https://doi.org/10.5194/acp-18-5821-2018, https://doi.org/10.5194/acp-18-5821-2018, 2018
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Here we use a combination of global convection-permitting models, satellite observations and the Holuhraun volcanic eruption to demonstrate that aerosol enhances the cloud liquid content and brightness of midlatitude cyclones. This is important because the strength of anthropogenic radiative forcing is uncertain, leading to uncertainty in the climate sensitivity consistent with observed temperature record.
James D. Lee, Stephen D. Mobbs, Axel Wellpott, Grant Allen, Stephane J.-B. Bauguitte, Ralph R. Burton, Richard Camilli, Hugh Coe, Rebecca E. Fisher, James L. France, Martin Gallagher, James R. Hopkins, Mathias Lanoiselle, Alastair C. Lewis, David Lowry, Euan G. Nisbet, Ruth M. Purvis, Sebastian O'Shea, John A. Pyle, and Thomas B. Ryerson
Atmos. Meas. Tech., 11, 1725–1739, https://doi.org/10.5194/amt-11-1725-2018, https://doi.org/10.5194/amt-11-1725-2018, 2018
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This work describes measurements, made from an aircraft platform, of the emission of methane and other organic gases from an uncontrolled leak from an oil platform in the North Sea (Total Elgin). The measurements made helped the platform operators to devise a strategy for repairing the leak and serve as a methodology for assessing future similar incidents.
Hazel M. Jones, Gillian Young, Thomas W. Choularton, Keith N. Bower, Thomas Lachlan-Cope, Sebastian O'Shea, James Dorsey, Russell Ladkin, Amelié Kirchgaessner, and Alexandra Weiss
Atmos. Chem. Phys. Discuss., https://doi.org/10.5194/acp-2018-283, https://doi.org/10.5194/acp-2018-283, 2018
Revised manuscript not accepted
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This paper presents new in-situ aerosol and cloud physics measurements from the Arctic during the summertime ACCACIA campaign. Data from eight flights in the vicinity of Svalbard are presented and compared to data from previous Arctic projects. It is hoped this dataset will be of use to modellers who wish to develop polar cloud parameterisations.
Dantong Liu, Jonathan W. Taylor, Jonathan Crosier, Nicholas Marsden, Keith N. Bower, Gary Lloyd, Claire L. Ryder, Jennifer K. Brooke, Richard Cotton, Franco Marenco, Alan Blyth, Zhiqiang Cui, Victor Estelles, Martin Gallagher, Hugh Coe, and Tom W. Choularton
Atmos. Chem. Phys., 18, 3817–3838, https://doi.org/10.5194/acp-18-3817-2018, https://doi.org/10.5194/acp-18-3817-2018, 2018
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This article presents measurements of aerosol properties off the coast of west Africa during August 2015. For the first time, an airborne laser-induced incandescence instrument was deployed to measure the hematite content of dust. The single scattering albedo of dust was found to be influenced by the hematite content, but depended on the dust source and potential dust age. This highlights the importance of size-dependent composition in determining the optical properties of dust.
Annette K. Miltenberger, Paul R. Field, Adrian A. Hill, Phil Rosenberg, Ben J. Shipway, Jonathan M. Wilkinson, Robert Scovell, and Alan M. Blyth
Atmos. Chem. Phys., 18, 3119–3145, https://doi.org/10.5194/acp-18-3119-2018, https://doi.org/10.5194/acp-18-3119-2018, 2018
Daniel T. McCoy, Frida A.-M. Bender, Daniel P. Grosvenor, Johannes K. Mohrmann, Dennis L. Hartmann, Robert Wood, and Paul R. Field
Atmos. Chem. Phys., 18, 2035–2047, https://doi.org/10.5194/acp-18-2035-2018, https://doi.org/10.5194/acp-18-2035-2018, 2018
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The interaction between clouds and aerosols represents the largest source of uncertainty in the anthropogenic radiative forcing. Cloud droplet number concentration (CDNC) is the state variable that moderates the interaction between aerosol and clouds. Here we show that CDNC decreases off the coasts of East Asia and North America due to controls on emissions. We support this analysis through an examination of volcanism in Hawaii and Vanuatu.
Kathryn Fowler, Paul J. Connolly, David O. Topping, and Simon O'Meara
Atmos. Chem. Phys., 18, 1629–1642, https://doi.org/10.5194/acp-18-1629-2018, https://doi.org/10.5194/acp-18-1629-2018, 2018
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This is the first time the Maxwell–Stefan framework has been applied to an atmospheric aerosol core–shell model and shows that there is a complex interplay between the viscous and solubility effects on aerosol composition. Understanding aerosol composition is essential to accurately model their interactions within atmospheric systems. We use simple binary systems to demonstrate how viscosity and solubility both play a role in affecting the rate of diffusion through aerosol particles.
Gillian Young, Paul J. Connolly, Christopher Dearden, and Thomas W. Choularton
Atmos. Chem. Phys., 18, 1475–1494, https://doi.org/10.5194/acp-18-1475-2018, https://doi.org/10.5194/acp-18-1475-2018, 2018
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Large-scale subsidence, associated with high-pressure systems, is often used in cloud-resolving models to maintain the height of boundary layer clouds; however, its influence on the small-scale interactions in mixed-phase clouds has not been previously investigated. Using large-eddy simulations, we have identified a relationship between subsidence and convection development in such clouds, with implications for mixed-phase boundary layer clouds forming in the ocean-exposed Arctic regions.
Olivia Goulden, Matthew Crooks, and Paul Connolly
Atmos. Chem. Phys., 18, 275–287, https://doi.org/10.5194/acp-18-275-2018, https://doi.org/10.5194/acp-18-275-2018, 2018
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The formation of cloud from the condensation of water vapour in the atmosphere on aerosol particles is highly dependent of the chemical properties of the particles. The chemistry is further complicated by the presence of condensible gases in the atmosphere other than water. We provide several methods of including the complicated chemical properties of the aerosol particles and condensing gases into single parameter descriptions, which are suitable for inclusion in large-scale models.
Ian Crawford, Martin W. Gallagher, Keith N. Bower, Thomas W. Choularton, Michael J. Flynn, Simon Ruske, Constantino Listowski, Neil Brough, Thomas Lachlan-Cope, Zoë L. Fleming, Virginia E. Foot, and Warren R. Stanley
Atmos. Chem. Phys., 17, 14291–14307, https://doi.org/10.5194/acp-17-14291-2017, https://doi.org/10.5194/acp-17-14291-2017, 2017
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We present the first real-time detection of bioparticles on the Antarctic continent using a novel UV-LIF technique. The high time resolution of the technique allowed us to examine the relationships between bioparticle concentrations and airmass history and local winds, which would not have been possible with conventional high-volume filter sampling techniques. We also show evidence of episodic long-range transport of pollen from coastal South America to the continent.
Sebastian J. O'Shea, Thomas W. Choularton, Michael Flynn, Keith N. Bower, Martin Gallagher, Jonathan Crosier, Paul Williams, Ian Crawford, Zoë L. Fleming, Constantino Listowski, Amélie Kirchgaessner, Russell S. Ladkin, and Thomas Lachlan-Cope
Atmos. Chem. Phys., 17, 13049–13070, https://doi.org/10.5194/acp-17-13049-2017, https://doi.org/10.5194/acp-17-13049-2017, 2017
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Few direct measurements have been made of Antarctic cloud and aerosol properties. As part of the 2015 Microphysics of Antarctic Clouds (MAC) field campaign, detailed airborne and ground-based measurements were made over the Weddell Sea and Antarctic coastal continent. This paper presents the first results from this campaign and discusses the cloud properties and processes important in this region.
Anja Costa, Jessica Meyer, Armin Afchine, Anna Luebke, Gebhard Günther, James R. Dorsey, Martin W. Gallagher, Andre Ehrlich, Manfred Wendisch, Darrel Baumgardner, Heike Wex, and Martina Krämer
Atmos. Chem. Phys., 17, 12219–12238, https://doi.org/10.5194/acp-17-12219-2017, https://doi.org/10.5194/acp-17-12219-2017, 2017
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The paper presents 38 h of in situ cloud spectrometer observations of microphysical cloud properties in the Arctic, midlatitudes and tropics. The clouds are classified via particle concentrations, size distributions, and – as a novelty – small particle aspherical fractions. Cloud-type profiles are given for different temperatures and locations. The results confine regions where different cloud transformation processes occurred and emphasise the importance of small particle shape detection.
Leonid Nichman, Emma Järvinen, James Dorsey, Paul Connolly, Jonathan Duplissy, Claudia Fuchs, Karoliina Ignatius, Kamalika Sengupta, Frank Stratmann, Ottmar Möhler, Martin Schnaiter, and Martin Gallagher
Atmos. Meas. Tech., 10, 3231–3248, https://doi.org/10.5194/amt-10-3231-2017, https://doi.org/10.5194/amt-10-3231-2017, 2017
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Optical probes are frequently used for the detection of cloud particles. The detected microphysical properties may affect particle growth and accretion mechanisms and the light scattering properties of cirrus clouds. In the CLOUD chamber study at CERN, we compared four optical measurement techniques. We show that shape derivation alone is not sufficient to determine the phase of the small cloud particles. None of the instruments were able to unambiguously determine the phase of small particles.
Daniel P. Grosvenor, Paul R. Field, Adrian A. Hill, and Benjamin J. Shipway
Atmos. Chem. Phys., 17, 5155–5183, https://doi.org/10.5194/acp-17-5155-2017, https://doi.org/10.5194/acp-17-5155-2017, 2017
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We used a weather model to simulate low-level layer clouds that lie off the coast of Chile and tested how they would be affected by airborne particulate matter (aerosols) according to the model. We found that as aerosols were increased, the clouds reflected more and more of the sun’s incoming energy due to the combined effects of the cloud droplets becoming smaller, the thickening of clouds, and increased areal coverage. However, the latter two effects were only important at low aerosol levels.
Gillian Young, Paul J. Connolly, Hazel M. Jones, and Thomas W. Choularton
Atmos. Chem. Phys., 17, 4209–4227, https://doi.org/10.5194/acp-17-4209-2017, https://doi.org/10.5194/acp-17-4209-2017, 2017
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Arctic mixed-phase clouds are poorly represented in numerical models, due in part to an overpredicted ice phase. Here, we examine the sensitivity of cloud structure, evolution, and lifetime to modelled primary ice number concentrations over three different surfaces – sea ice, marginal ice, and ocean – to investigate the dependency on both the ice phase and dynamics induced from surface fluxes.
Céline Planche, Graham W. Mann, Kenneth S. Carslaw, Mohit Dalvi, John H. Marsham, and Paul R. Field
Atmos. Chem. Phys., 17, 3371–3384, https://doi.org/10.5194/acp-17-3371-2017, https://doi.org/10.5194/acp-17-3371-2017, 2017
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A convection-permitting limited area model with prognostic aerosol microphysics is applied to investigate how concentrations of cloud condensation nuclei (CCN) in the marine boundary layer are affected by high-resolution dynamical and thermodynamic fields at sub-climate model scale. We gain new insight into the way primary sea-salt and secondary sulfate particles contribute to the overall CCN variance, and find a marked difference in the variability of super- and sub-micron CCN.
Simon Ruske, David O. Topping, Virginia E. Foot, Paul H. Kaye, Warren R. Stanley, Ian Crawford, Andrew P. Morse, and Martin W. Gallagher
Atmos. Meas. Tech., 10, 695–708, https://doi.org/10.5194/amt-10-695-2017, https://doi.org/10.5194/amt-10-695-2017, 2017
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Particles such as bacteria, pollen and fungal spores have important implications within the environment and public health sectors. Here we evaluate the performance of various different methods for distinguishing between these different types of particles using a new instrument. We demonstrate that there may be better alternatives to the currently used methods which can be further investigated in future research.
Nicholas Marsden, Michael J. Flynn, Jonathan W. Taylor, James D. Allan, and Hugh Coe
Atmos. Meas. Tech., 9, 6051–6068, https://doi.org/10.5194/amt-9-6051-2016, https://doi.org/10.5194/amt-9-6051-2016, 2016
Marie Ila Gosselin, Chathurika M. Rathnayake, Ian Crawford, Christopher Pöhlker, Janine Fröhlich-Nowoisky, Beatrice Schmer, Viviane R. Després, Guenter Engling, Martin Gallagher, Elizabeth Stone, Ulrich Pöschl, and J. Alex Huffman
Atmos. Chem. Phys., 16, 15165–15184, https://doi.org/10.5194/acp-16-15165-2016, https://doi.org/10.5194/acp-16-15165-2016, 2016
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We present an analysis of bioaerosol measurements using two real-time fluorescence instruments in combination with molecular tracer techniques for quantifying airborne fungal spores in a semi-arid forest. Both techniques provide fungal spore concentrations of the order of 104 m−3 and up to 30 % of particle mass. Rainy periods exhibited higher concentrations and stronger correlations between fluorescent bioparticle and molecular tracer measurements. Fungal culture results are also presented.
Gillian Young, Hazel M. Jones, Thomas W. Choularton, Jonathan Crosier, Keith N. Bower, Martin W. Gallagher, Rhiannon S. Davies, Ian A. Renfrew, Andrew D. Elvidge, Eoghan Darbyshire, Franco Marenco, Philip R. A. Brown, Hugo M. A. Ricketts, Paul J. Connolly, Gary Lloyd, Paul I. Williams, James D. Allan, Jonathan W. Taylor, Dantong Liu, and Michael J. Flynn
Atmos. Chem. Phys., 16, 13945–13967, https://doi.org/10.5194/acp-16-13945-2016, https://doi.org/10.5194/acp-16-13945-2016, 2016
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Clouds are intricately coupled to the Arctic sea ice. Our inability to accurately model cloud fractions causes large uncertainties in predicted radiative interactions in this region, therefore, affecting sea ice forecasts. Here, we present measurements of cloud microphysics, aerosol properties, and thermodynamic structure over the transition from sea ice to ocean to improve our understanding of the relationship between the Arctic atmosphere and clouds which develop in this region.
Matthew Crooks, Paul Connolly, David Topping, and Gordon McFiggans
Geosci. Model Dev., 9, 3617–3637, https://doi.org/10.5194/gmd-9-3617-2016, https://doi.org/10.5194/gmd-9-3617-2016, 2016
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Semi-volatile compounds, like water, can exist in both vapour phases and condensed phases within a system. This paper presents a method of calculating the condensed and vapour phases of semi-volatile compounds at equilibrium, in particular, when the condensed mass occurs within particles of different sizes and chemical composition. The applications of interest to the authors are those of atmospheric importance such as cloud droplet formation and reflection or absorption of solar radiation.
Jonathan W. Taylor, Thomas W. Choularton, Alan M. Blyth, Michael J. Flynn, Paul I. Williams, Gillian Young, Keith N. Bower, Jonathan Crosier, Martin W. Gallagher, James R. Dorsey, Zixia Liu, and Philip D. Rosenberg
Atmos. Chem. Phys., 16, 11687–11709, https://doi.org/10.5194/acp-16-11687-2016, https://doi.org/10.5194/acp-16-11687-2016, 2016
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We present measurements of boundary layer aerosol concentration, size and composition from research flights performed over the southwest peninsula of the UK during the COnvective Precipitation Experiment (COPE) of summer 2013. We compare case studies of aerosol in cleaner marine air from the Atlantic with anthropogenic pollution from the UK. These measurements are then used to investigate the possible sources of CCN and IN in the region.
James D. Whitehead, Eoghan Darbyshire, Joel Brito, Henrique M. J. Barbosa, Ian Crawford, Rafael Stern, Martin W. Gallagher, Paul H. Kaye, James D. Allan, Hugh Coe, Paulo Artaxo, and Gordon McFiggans
Atmos. Chem. Phys., 16, 9727–9743, https://doi.org/10.5194/acp-16-9727-2016, https://doi.org/10.5194/acp-16-9727-2016, 2016
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We present measurements of aerosols during the transition from wet to dry seasons at a pristine rainforest site in central Amazonia. By excluding pollution episodes, we focus on natural biogenic aerosols. Submicron aerosols are dominated by organic material, similar to previous wet season measurements. Larger particles are dominated by biological material, mostly fungal spores, with higher concentrations at night. This study provides important data on the nature of particles above the Amazon.
Karoliina Ignatius, Thomas B. Kristensen, Emma Järvinen, Leonid Nichman, Claudia Fuchs, Hamish Gordon, Paul Herenz, Christopher R. Hoyle, Jonathan Duplissy, Sarvesh Garimella, Antonio Dias, Carla Frege, Niko Höppel, Jasmin Tröstl, Robert Wagner, Chao Yan, Antonio Amorim, Urs Baltensperger, Joachim Curtius, Neil M. Donahue, Martin W. Gallagher, Jasper Kirkby, Markku Kulmala, Ottmar Möhler, Harald Saathoff, Martin Schnaiter, Antonio Tomé, Annele Virtanen, Douglas Worsnop, and Frank Stratmann
Atmos. Chem. Phys., 16, 6495–6509, https://doi.org/10.5194/acp-16-6495-2016, https://doi.org/10.5194/acp-16-6495-2016, 2016
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Viscous solid or semi-solid secondary organic aerosol (SOA) may influence cloud properties through ice nucleation in the atmosphere. Here, we observed heterogeneous ice nucleation of viscous α-pinene SOA at temperatures between −39 °C and −37.2 °C with ice saturation ratios significantly below the homogeneous freezing limit. Global modelling suggests that viscous biogenic SOA are present in regions where cirrus formation takes place and could contribute to the global ice nuclei budget.
Rebecca M. McKenzie, Mustafa Z. Özel, J. Neil Cape, Julia Drewer, Kerry J. Dinsmore, Eiko Nemitz, Y. Sim Tang, Netty van Dijk, Margaret Anderson, Jacqueline F. Hamilton, Mark A. Sutton, Martin W. Gallagher, and Ute Skiba
Biogeosciences, 13, 2353–2365, https://doi.org/10.5194/bg-13-2353-2016, https://doi.org/10.5194/bg-13-2353-2016, 2016
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Dissolved organic nitrogen (DON) contributes significantly to the overall nitrogen budget and can potentially be biologically available as a source of N. Despite this it is not routinely measured. This study found that DON contributed up to 10 % of the total dissolved nitrogen (TDN) found in precipitation and was the most dominant fraction in soil water (99 %) and stream water (75 %).
Emma Järvinen, Karoliina Ignatius, Leonid Nichman, Thomas B. Kristensen, Claudia Fuchs, Christopher R. Hoyle, Niko Höppel, Joel C. Corbin, Jill Craven, Jonathan Duplissy, Sebastian Ehrhart, Imad El Haddad, Carla Frege, Hamish Gordon, Tuija Jokinen, Peter Kallinger, Jasper Kirkby, Alexei Kiselev, Karl-Heinz Naumann, Tuukka Petäjä, Tamara Pinterich, Andre S. H. Prevot, Harald Saathoff, Thea Schiebel, Kamalika Sengupta, Mario Simon, Jay G. Slowik, Jasmin Tröstl, Annele Virtanen, Paul Vochezer, Steffen Vogt, Andrea C. Wagner, Robert Wagner, Christina Williamson, Paul M. Winkler, Chao Yan, Urs Baltensperger, Neil M. Donahue, Rick C. Flagan, Martin Gallagher, Armin Hansel, Markku Kulmala, Frank Stratmann, Douglas R. Worsnop, Ottmar Möhler, Thomas Leisner, and Martin Schnaiter
Atmos. Chem. Phys., 16, 4423–4438, https://doi.org/10.5194/acp-16-4423-2016, https://doi.org/10.5194/acp-16-4423-2016, 2016
G. Young, H. M. Jones, E. Darbyshire, K. J. Baustian, J. B. McQuaid, K. N. Bower, P. J. Connolly, M. W. Gallagher, and T. W. Choularton
Atmos. Chem. Phys., 16, 4063–4079, https://doi.org/10.5194/acp-16-4063-2016, https://doi.org/10.5194/acp-16-4063-2016, 2016
Leonid Nichman, Claudia Fuchs, Emma Järvinen, Karoliina Ignatius, Niko Florian Höppel, Antonio Dias, Martin Heinritzi, Mario Simon, Jasmin Tröstl, Andrea Christine Wagner, Robert Wagner, Christina Williamson, Chao Yan, Paul James Connolly, James Robert Dorsey, Jonathan Duplissy, Sebastian Ehrhart, Carla Frege, Hamish Gordon, Christopher Robert Hoyle, Thomas Bjerring Kristensen, Gerhard Steiner, Neil McPherson Donahue, Richard Flagan, Martin William Gallagher, Jasper Kirkby, Ottmar Möhler, Harald Saathoff, Martin Schnaiter, Frank Stratmann, and António Tomé
Atmos. Chem. Phys., 16, 3651–3664, https://doi.org/10.5194/acp-16-3651-2016, https://doi.org/10.5194/acp-16-3651-2016, 2016
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Processes in the atmosphere are often governed by the physical and chemical properties of small cloud particles. Ice, water, and mixed clouds, as well as viscous aerosols, were formed under controlled conditions at the CLOUD-CERN facility. The experimental results show a link between cloud particle properties and their unique optical fingerprints. The classification map presented here allows easier discrimination between various particles such as viscous organic aerosol, salt, ice, and liquid.
I. Crawford, G. Lloyd, E. Herrmann, C. R. Hoyle, K. N. Bower, P. J. Connolly, M. J. Flynn, P. H. Kaye, T. W. Choularton, and M. W. Gallagher
Atmos. Chem. Phys., 16, 2273–2284, https://doi.org/10.5194/acp-16-2273-2016, https://doi.org/10.5194/acp-16-2273-2016, 2016
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In this manuscript we discuss observations of fluorescent aerosol and their interactions with cloud at a high-alpine site in the wintertime under background conditions. We find the majority of the fluorescent aerosol to be consistent in nature to mineral dust and no apparent trend was observed between the fluorescent aerosol fraction and meteorological or cloud microphysical parameters, suggesting that particle fluorescence does not impact cloud evolution or formation at the site.
C. R. Hoyle, C. Fuchs, E. Järvinen, H. Saathoff, A. Dias, I. El Haddad, M. Gysel, S. C. Coburn, J. Tröstl, A.-K. Bernhammer, F. Bianchi, M. Breitenlechner, J. C. Corbin, J. Craven, N. M. Donahue, J. Duplissy, S. Ehrhart, C. Frege, H. Gordon, N. Höppel, M. Heinritzi, T. B. Kristensen, U. Molteni, L. Nichman, T. Pinterich, A. S. H. Prévôt, M. Simon, J. G. Slowik, G. Steiner, A. Tomé, A. L. Vogel, R. Volkamer, A. C. Wagner, R. Wagner, A. S. Wexler, C. Williamson, P. M. Winkler, C. Yan, A. Amorim, J. Dommen, J. Curtius, M. W. Gallagher, R. C. Flagan, A. Hansel, J. Kirkby, M. Kulmala, O. Möhler, F. Stratmann, D. R. Worsnop, and U. Baltensperger
Atmos. Chem. Phys., 16, 1693–1712, https://doi.org/10.5194/acp-16-1693-2016, https://doi.org/10.5194/acp-16-1693-2016, 2016
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A significant portion of sulphate, an important constituent of atmospheric aerosols, is formed via the aqueous phase oxidation of sulphur dioxide by ozone. The rate of this reaction has previously only been measured over a relatively small temperature range. Here, we use the state of the art CLOUD chamber at CERN to perform the first measurements of this reaction rate in super-cooled droplets, confirming that the existing extrapolation of the reaction rate to sub-zero temperatures is accurate.
J. W. Taylor, T. W. Choularton, A. M. Blyth, Z. Liu, K. N. Bower, J. Crosier, M. W. Gallagher, P. I. Williams, J. R. Dorsey, M. J. Flynn, L. J. Bennett, Y. Huang, J. French, A. Korolev, and P. R. A. Brown
Atmos. Chem. Phys., 16, 799–826, https://doi.org/10.5194/acp-16-799-2016, https://doi.org/10.5194/acp-16-799-2016, 2016
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We present microphysical observations of cumulus clouds measured over south-west England during COPE in summer 2013. Detailed sampling focused on an isolated liquid cloud that glaciated as it matured to merge with a band of cloud downwind. The first ice particles observed were frozen drizzle, while columnar ice dominated in the mature stages. We discuss the interactions between the warm rain and secondary ice processes, and their importance for the formation of precipitation.
J. R. Pitt, M. Le Breton, G. Allen, C. J. Percival, M. W. Gallagher, S. J.-B. Bauguitte, S. J. O'Shea, J. B. A. Muller, M. S. Zahniser, J. Pyle, and P. I. Palmer
Atmos. Meas. Tech., 9, 63–77, https://doi.org/10.5194/amt-9-63-2016, https://doi.org/10.5194/amt-9-63-2016, 2016
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We present details of an Aerodyne quantum cascade laser absorption spectrometer (QCLAS) used to make airborne measurements of N2O and CH4, including its configuration for use on board an aircraft. Two different methods to correct for the influence of water vapour on the measurements are evaluated. We diagnose a sensitivity of the instrument to changes in pressure, introduce a new calibration procedure to account for this effect, and assess its performance.
J. Grazioli, G. Lloyd, L. Panziera, C. R. Hoyle, P. J. Connolly, J. Henneberger, and A. Berne
Atmos. Chem. Phys., 15, 13787–13802, https://doi.org/10.5194/acp-15-13787-2015, https://doi.org/10.5194/acp-15-13787-2015, 2015
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This study investigates the microphysics of winter alpine snowfall occurring in mixed-phase clouds in an inner-Alpine valley during CLACE2014. From polarimetric radar and in situ observations, riming is shown to be an important process leading to more intense snowfall. Riming is usually associated with more intense turbulence providing supercooled liquid water. Distinct features are identified in the vertical structure of polarimetric radar variables.
I. Crawford, S. Ruske, D. O. Topping, and M. W. Gallagher
Atmos. Meas. Tech., 8, 4979–4991, https://doi.org/10.5194/amt-8-4979-2015, https://doi.org/10.5194/amt-8-4979-2015, 2015
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HCA analysis methods were evaluated for the purpose of identifying primary biological aerosol sampled with a WIBS. The ward linkage with z-score normalisation could discriminate between five test particles with 98% accuracy. We applied these methods to a previously studied ambient data set, where both methods produced similar results with some minor differences in cluster partitioning. Finally we compared to previous approaches and found our new method offered improved quantification of PBA.
G. Lloyd, T. W. Choularton, K. N. Bower, M. W. Gallagher, P. J. Connolly, M. Flynn, R. Farrington, J. Crosier, O. Schlenczek, J. Fugal, and J. Henneberger
Atmos. Chem. Phys., 15, 12953–12969, https://doi.org/10.5194/acp-15-12953-2015, https://doi.org/10.5194/acp-15-12953-2015, 2015
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The paper explores the microphysical structure of clouds at the high-alpine measurement site Jungfraujoch, Switzerland. High concentrations of ice crystals were measured by a range of instruments. The presence of these high concentrations could not be explained through conventional understanding of ice formation processes in clouds and the possibility that the surface provides a significant source of ice crystals is investigated.
D. Liu, B. Quennehen, E. Darbyshire, J. D. Allan, P. I. Williams, J. W. Taylor, S. J.-B. Bauguitte, M. J. Flynn, D. Lowe, M. W. Gallagher, K. N. Bower, T. W. Choularton, and H. Coe
Atmos. Chem. Phys., 15, 11537–11555, https://doi.org/10.5194/acp-15-11537-2015, https://doi.org/10.5194/acp-15-11537-2015, 2015
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We show that during the springtime of 2013, the anthropogenic pollution particularly from sources in Asia, contributed significantly to black carbon across the European Arctic free troposphere. In contrast to previous studies, the contribution from open wildfires was minimal. Given that Asian pollution is likely to continue to rise over the coming years, it is likely that the radiative forcing in the Arctic will also continue to increase.
C. Emersic, P. J. Connolly, S. Boult, M. Campana, and Z. Li
Atmos. Chem. Phys., 15, 11311–11326, https://doi.org/10.5194/acp-15-11311-2015, https://doi.org/10.5194/acp-15-11311-2015, 2015
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D. E. Young, J. D. Allan, P. I. Williams, D. C. Green, M. J. Flynn, R. M. Harrison, J. Yin, M. W. Gallagher, and H. Coe
Atmos. Chem. Phys., 15, 6351–6366, https://doi.org/10.5194/acp-15-6351-2015, https://doi.org/10.5194/acp-15-6351-2015, 2015
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For the first time, the behaviour of non-refractory inorganic and organic submicron particulates through an entire annual cycle is investigated at a UK urban background site. We show secondary aerosols account for a significant fraction of the submicron aerosol burden, high concentration events are governed by different factors depending on season, and on an annual basis there is no variability in the extent of secondary organic aerosol oxidation.
M. Hummel, C. Hoose, M. Gallagher, D. A. Healy, J. A. Huffman, D. O'Connor, U. Pöschl, C. Pöhlker, N. H. Robinson, M. Schnaiter, J. R. Sodeau, M. Stengel, E. Toprak, and H. Vogel
Atmos. Chem. Phys., 15, 6127–6146, https://doi.org/10.5194/acp-15-6127-2015, https://doi.org/10.5194/acp-15-6127-2015, 2015
J. D. Allan, P. I. Williams, J. Najera, J. D. Whitehead, M. J. Flynn, J. W. Taylor, D. Liu, E. Darbyshire, L. J. Carpenter, R. Chance, S. J. Andrews, S. C. Hackenberg, and G. McFiggans
Atmos. Chem. Phys., 15, 5599–5609, https://doi.org/10.5194/acp-15-5599-2015, https://doi.org/10.5194/acp-15-5599-2015, 2015
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New particle formation (NPF) is an important contributor to aerosol number concentrations in the Arctic and thus has a major role in dictating cloud properties and climate in this region. Here we present direct evidence that the oxidation of iodine in the atmosphere causes NPF in the Greenland Sea. This is important because this is a NPF mechanism that has not previously been considered in modelling studies at these latitudes.
J. W. Taylor, J. D. Allan, D. Liu, M. Flynn, R. Weber, X. Zhang, B. L. Lefer, N. Grossberg, J. Flynn, and H. Coe
Atmos. Meas. Tech., 8, 1701–1718, https://doi.org/10.5194/amt-8-1701-2015, https://doi.org/10.5194/amt-8-1701-2015, 2015
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When using the SP2 to report black carbon core/shell coating thickness, the core density and refractive index must be estimated from literature values. We systematically vary the assumed parameters and the instrument calibration, and quantify the effects in the derived coatings. The technique is highly sensitive to the core refractive index but has only a minor sensitivity to the core density and coating refractive index. We identify the most appropriate values to use in future analysis.
I. Steinke, C. Hoose, O. Möhler, P. Connolly, and T. Leisner
Atmos. Chem. Phys., 15, 3703–3717, https://doi.org/10.5194/acp-15-3703-2015, https://doi.org/10.5194/acp-15-3703-2015, 2015
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Ice nucleation in clouds has a significant influence on the global radiative budget and the hydrological cycle. Several studies have investigated the ice formation in droplets and parameterizations have been developed in order to include immersion freezing in climate models. In contrast, there are fewer studies regarding the conversion of water vapor into ice (so-called deposition nucleation) which is the topic of this paper which investigates deposition nucleation by Arizona Test dust in detail
G. Lloyd, T. W. Choularton, K. N. Bower, J. Crosier, H. Jones, J. R. Dorsey, M. W. Gallagher, P. Connolly, A. C. R. Kirchgaessner, and T. Lachlan-Cope
Atmos. Chem. Phys., 15, 3719–3737, https://doi.org/10.5194/acp-15-3719-2015, https://doi.org/10.5194/acp-15-3719-2015, 2015
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Measurements of cloud microphysics are reported from the Aerosol-Cloud Coupling And Climate Interactions (ACCACIA) campaign. Concentrations of ice particles from two spring and two summer cases are compared with particular attention to the role of secondary ice in these clouds. In addition aerosol measurements were used as input to a primary ice nucleation parameterisation which was compared with observed values of primary ice in these clouds. We found higher concentrations of ice during summer.
L. R. Crilley, W. J. Bloss, J. Yin, D. C. S. Beddows, R. M. Harrison, J. D. Allan, D. E. Young, M. Flynn, P. Williams, P. Zotter, A. S. H. Prevot, M. R. Heal, J. F. Barlow, C. H. Halios, J. D. Lee, S. Szidat, and C. Mohr
Atmos. Chem. Phys., 15, 3149–3171, https://doi.org/10.5194/acp-15-3149-2015, https://doi.org/10.5194/acp-15-3149-2015, 2015
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Wood is a renewable fuel but its combustion for residential heating releases a number of locally acting air pollutants, most notably particulate matter known to have adverse effects on human health. This paper used chemical tracers for wood smoke to estimate the contribution that burning wood makes to concentrations of airborne particles in the atmosphere of southern England and most particularly in London.
D. E. Young, J. D. Allan, P. I. Williams, D. C. Green, R. M. Harrison, J. Yin, M. J. Flynn, M. W. Gallagher, and H. Coe
Atmos. Chem. Phys., 15, 2429–2443, https://doi.org/10.5194/acp-15-2429-2015, https://doi.org/10.5194/acp-15-2429-2015, 2015
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Two solid fuel organic aerosol (SFOA) factors, both associated with domestic space heating activities, were derived from positive matrix factorisation (PMF) applied to organic aerosol data from an aerosol mass spectrometer (AMS) deployed at an urban background site in London during winter 2012. The factors controlling the split between the two SFOA factors were assessed, and it is concluded the split is likely governed predominantly by differences in burn conditions.
A. Korolev and P. R. Field
Atmos. Meas. Tech., 8, 761–777, https://doi.org/10.5194/amt-8-761-2015, https://doi.org/10.5194/amt-8-761-2015, 2015
W. T. Morgan, B. Ouyang, J. D. Allan, E. Aruffo, P. Di Carlo, O. J. Kennedy, D. Lowe, M. J. Flynn, P. D. Rosenberg, P. I. Williams, R. Jones, G. B. McFiggans, and H. Coe
Atmos. Chem. Phys., 15, 973–990, https://doi.org/10.5194/acp-15-973-2015, https://doi.org/10.5194/acp-15-973-2015, 2015
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This paper used observations from a research aircraft flying around the UK to investigate how air pollution in north-western Europe can alter nighttime chemical reactions in the atmosphere. These chemical reactions can worsen air quality in the region, as well as influence regional climate change. Ammonium nitrate aerosol appears to play an important role. The paper indicates that representation of these chemical reactions is poorly represented in models used for air quality and climate.
J. W. Taylor, J. D. Allan, G. Allen, H. Coe, P. I. Williams, M. J. Flynn, M. Le Breton, J. B. A. Muller, C. J. Percival, D. Oram, G. Forster, J. D. Lee, A. R. Rickard, M. Parrington, and P. I. Palmer
Atmos. Chem. Phys., 14, 13755–13771, https://doi.org/10.5194/acp-14-13755-2014, https://doi.org/10.5194/acp-14-13755-2014, 2014
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We present a case study of BC wet removal by examining aerosol properties in three biomass burning plumes, one of which passed through a precipitating cloud. Nucleation scavenging preferentially removed the largest and most coated BC-containing particles. Calculated single-scattering albedo (SSA) showed little variation, as a large number of non-BC particles were also present in the precipitation-affected plume.
G. Allen, S. M. Illingworth, S. J. O'Shea, S. Newman, A. Vance, S. J.-B. Bauguitte, F. Marenco, J. Kent, K. Bower, M. W. Gallagher, J. Muller, C. J. Percival, C. Harlow, J. Lee, and J. P. Taylor
Atmos. Meas. Tech., 7, 4401–4416, https://doi.org/10.5194/amt-7-4401-2014, https://doi.org/10.5194/amt-7-4401-2014, 2014
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This paper presents a validated method and data set for new retrievals of trace gas concentrations and temperature from the ARIES infrared spectrometer instrument on the UK Atmospheric Research Aircraft (www.faam.ac.uk). This new capability for the aircraft will allow new science to be done because of the way it can sense information about the atmosphere without having to physically pass through it (remote sensing). This will allow us to better understand the make-up of the lower atmosphere.
S. J. O'Shea, G. Allen, M. W. Gallagher, K. Bower, S. M. Illingworth, J. B. A. Muller, B. T. Jones, C. J. Percival, S. J-B. Bauguitte, M. Cain, N. Warwick, A. Quiquet, U. Skiba, J. Drewer, K. Dinsmore, E. G. Nisbet, D. Lowry, R. E. Fisher, J. L. France, M. Aurela, A. Lohila, G. Hayman, C. George, D. B. Clark, A. J. Manning, A. D. Friend, and J. Pyle
Atmos. Chem. Phys., 14, 13159–13174, https://doi.org/10.5194/acp-14-13159-2014, https://doi.org/10.5194/acp-14-13159-2014, 2014
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This paper presents airborne measurements of greenhouse gases collected in the European Arctic. Regional scale flux estimates for the northern Scandinavian wetlands are derived. These fluxes are found to be in excellent agreement with coincident surface measurements within the aircraft's sampling domain. This has allowed a significant low bias to be identified in two commonly used process-based land surface models.
J. D. Allan, W. T. Morgan, E. Darbyshire, M. J. Flynn, P. I. Williams, D. E. Oram, P. Artaxo, J. Brito, J. D. Lee, and H. Coe
Atmos. Chem. Phys., 14, 11393–11407, https://doi.org/10.5194/acp-14-11393-2014, https://doi.org/10.5194/acp-14-11393-2014, 2014
D. Liu, J. D. Allan, D. E. Young, H. Coe, D. Beddows, Z. L. Fleming, M. J. Flynn, M. W. Gallagher, R. M. Harrison, J. Lee, A. S. H. Prevot, J. W. Taylor, J. Yin, P. I. Williams, and P. Zotter
Atmos. Chem. Phys., 14, 10061–10084, https://doi.org/10.5194/acp-14-10061-2014, https://doi.org/10.5194/acp-14-10061-2014, 2014
D. P. Grosvenor, J. C. King, T. W. Choularton, and T. Lachlan-Cope
Atmos. Chem. Phys., 14, 9481–9509, https://doi.org/10.5194/acp-14-9481-2014, https://doi.org/10.5194/acp-14-9481-2014, 2014
I. Crawford, N. H. Robinson, M. J. Flynn, V. E. Foot, M. W. Gallagher, J. A. Huffman, W. R. Stanley, and P. H. Kaye
Atmos. Chem. Phys., 14, 8559–8578, https://doi.org/10.5194/acp-14-8559-2014, https://doi.org/10.5194/acp-14-8559-2014, 2014
E. Simpson, P. Connolly, and G. McFiggans
Geosci. Model Dev., 7, 1535–1542, https://doi.org/10.5194/gmd-7-1535-2014, https://doi.org/10.5194/gmd-7-1535-2014, 2014
K. Beswick, D. Baumgardner, M. Gallagher, A. Volz-Thomas, P. Nedelec, K.-Y. Wang, and S. Lance
Atmos. Meas. Tech., 7, 1443–1457, https://doi.org/10.5194/amt-7-1443-2014, https://doi.org/10.5194/amt-7-1443-2014, 2014
P. J. Connolly, D. O. Topping, F. Malavelle, and G. McFiggans
Atmos. Chem. Phys., 14, 2289–2302, https://doi.org/10.5194/acp-14-2289-2014, https://doi.org/10.5194/acp-14-2289-2014, 2014
S. J. O'Shea, G. Allen, M. W. Gallagher, S. J.-B. Bauguitte, S. M. Illingworth, M. Le Breton, J. B. A. Muller, C. J. Percival, A. T. Archibald, D. E. Oram, M. Parrington, P. I. Palmer, and A. C. Lewis
Atmos. Chem. Phys., 13, 12451–12467, https://doi.org/10.5194/acp-13-12451-2013, https://doi.org/10.5194/acp-13-12451-2013, 2013
A. M. Gabey, M. Vaitilingom, E. Freney, J. Boulon, K. Sellegri, M. W. Gallagher, I. P. Crawford, N. H. Robinson, W. R. Stanley, and P. H. Kaye
Atmos. Chem. Phys., 13, 7415–7428, https://doi.org/10.5194/acp-13-7415-2013, https://doi.org/10.5194/acp-13-7415-2013, 2013
P. J. Connolly, G. Vaughan, P. Cook, G. Allen, H. Coe, T. W. Choularton, C. Dearden, and A. Hill
Atmos. Chem. Phys., 13, 7133–7152, https://doi.org/10.5194/acp-13-7133-2013, https://doi.org/10.5194/acp-13-7133-2013, 2013
J. A. Huffman, A. J. Prenni, P. J. DeMott, C. Pöhlker, R. H. Mason, N. H. Robinson, J. Fröhlich-Nowoisky, Y. Tobo, V. R. Després, E. Garcia, D. J. Gochis, E. Harris, I. Müller-Germann, C. Ruzene, B. Schmer, B. Sinha, D. A. Day, M. O. Andreae, J. L. Jimenez, M. Gallagher, S. M. Kreidenweis, A. K. Bertram, and U. Pöschl
Atmos. Chem. Phys., 13, 6151–6164, https://doi.org/10.5194/acp-13-6151-2013, https://doi.org/10.5194/acp-13-6151-2013, 2013
C. L. Reddington, G. McMeeking, G. W. Mann, H. Coe, M. G. Frontoso, D. Liu, M. Flynn, D. V. Spracklen, and K. S. Carslaw
Atmos. Chem. Phys., 13, 4917–4939, https://doi.org/10.5194/acp-13-4917-2013, https://doi.org/10.5194/acp-13-4917-2013, 2013
S. J. O'Shea, S. J.-B. Bauguitte, M. W. Gallagher, D. Lowry, and C. J. Percival
Atmos. Meas. Tech., 6, 1095–1109, https://doi.org/10.5194/amt-6-1095-2013, https://doi.org/10.5194/amt-6-1095-2013, 2013
J. Skrotzki, P. Connolly, M. Schnaiter, H. Saathoff, O. Möhler, R. Wagner, M. Niemand, V. Ebert, and T. Leisner
Atmos. Chem. Phys., 13, 4451–4466, https://doi.org/10.5194/acp-13-4451-2013, https://doi.org/10.5194/acp-13-4451-2013, 2013
D. Liu, J. Allan, J. Whitehead, D. Young, M. Flynn, H. Coe, G. McFiggans, Z. L. Fleming, and B. Bandy
Atmos. Chem. Phys., 13, 2015–2029, https://doi.org/10.5194/acp-13-2015-2013, https://doi.org/10.5194/acp-13-2015-2013, 2013
N. H. Robinson, J. D. Allan, J. A. Huffman, P. H. Kaye, V. E. Foot, and M. Gallagher
Atmos. Meas. Tech., 6, 337–347, https://doi.org/10.5194/amt-6-337-2013, https://doi.org/10.5194/amt-6-337-2013, 2013
N. J. King, K. N. Bower, J. Crosier, and I. Crawford
Atmos. Chem. Phys., 13, 191–209, https://doi.org/10.5194/acp-13-191-2013, https://doi.org/10.5194/acp-13-191-2013, 2013
M. Laborde, M. Schnaiter, C. Linke, H. Saathoff, K.-H. Naumann, O. Möhler, S. Berlenz, U. Wagner, J. W. Taylor, D. Liu, M. Flynn, J. D. Allan, H. Coe, K. Heimerl, F. Dahlkötter, B. Weinzierl, A. G. Wollny, M. Zanatta, J. Cozic, P. Laj, R. Hitzenberger, J. P. Schwarz, and M. Gysel
Atmos. Meas. Tech., 5, 3077–3097, https://doi.org/10.5194/amt-5-3077-2012, https://doi.org/10.5194/amt-5-3077-2012, 2012
Related subject area
Subject: Clouds and Precipitation | Research Activity: Atmospheric Modelling and Data Analysis | Altitude Range: Troposphere | Science Focus: Physics (physical properties and processes)
Correction of ERA5 temperature and relative humidity biases by bivariate quantile mapping for contrail formation analysis
Can pollen affect precipitation?
Potential impacts of marine fuel regulations on an Arctic stratocumulus case and its radiative response
The impact of the mesh size and microphysics scheme on the representation of mid-level clouds in the ICON model in hilly and complex terrain
The role of ascent timescales for warm conveyor belt (WCB) moisture transport into the upper troposphere and lower stratosphere (UTLS)
Estimating the concentration of silver iodide needed to detect unambiguous signatures of glaciogenic cloud seeding
Ice-nucleating particle concentration impacts cloud properties over Dronning Maud Land, East Antarctica, in COSMO-CLM2
Numerical simulation of aerosol concentration effects on cloud droplet size spectrum evolutions of warm stratiform clouds in Jiangxi, China
The impact of aerosol on cloud water: a heuristic perspective
The presence of clouds lowers climate sensitivity in the MPI-ESM1.2 climate model
Diurnal variation in an amplified canopy urban heat island during heat wave periods in the megacity of Beijing: roles of mountain–valley breeze and urban morphology
Diurnal evolution of non-precipitating marine stratocumuli in a large-eddy simulation ensemble
High ice water content in tropical mesoscale convective systems (a conceptual model)
Evolution of cloud droplet temperature and lifetime in spatiotemporally varying subsaturated environments with implications for ice nucleation at cloud edges
Effect of secondary ice production processes on the simulation of ice pellets using the Predicted Particle Properties microphysics scheme
Simulated particle evolution within a winter storm: contributions of riming to radar moments and precipitation fallout
A thermal-driven graupel generation process to explain dry-season convective vigor over the Amazon
Modeling homogeneous ice nucleation from drop-freezing experiments: impact of droplet volume dispersion and cooling rates
Cloud water adjustments to aerosol perturbations are buffered by solar heating in non-precipitating marine stratocumuli
Glaciation of mixed-phase clouds: insights from bulk model and bin-microphysics large-eddy simulation informed by laboratory experiment
Microphysical processes involving the vapour phase dominate in simulated low-level Arctic clouds
Understanding aerosol–cloud interactions using a single-column model for a cold-air outbreak case during the ACTIVATE campaign
Investigating ice formation pathways using a novel two-moment multi-class cloud microphysics scheme
On the sensitivity of aerosol–cloud interactions to changes in sea surface temperature in radiative–convective equilibrium
Exploring aerosol–cloud interactions in liquid-phase clouds over eastern China and its adjacent ocean using the WRF-Chem–SBM model
How the representation of microphysical processes affects tropical condensate in a global storm-resolving model
Impact of secondary ice production on thunderstorm electrification under different aerosol conditions
Finite domains cause bias in measured and modeled distributions of cloud sizes
A systematic evaluation of high-cloud controlling factors
Tracking precipitation features and associated large-scale environments over southeastern Texas
Revisiting the evolution of downhill thunderstorms over Beijing: a new perspective from a radar wind profiler mesonet
How well can persistent contrails be predicted? An update
Model analysis of biases in satellite diagnosed aerosol effect on cloud liquid water path
Dynamical imprints on precipitation cluster statistics across a hierarchy of high-resolution simulations
Present-day correlations are insufficient to predict cloud albedo change by anthropogenic aerosols in E3SM v2
Simulations of primary and secondary ice production during an Arctic mixed-phase cloud case from the Ny-Ålesund Aerosol Cloud Experiment (NASCENT) campaign
Microphysical characteristics of precipitation within convective overshooting over East China observed by GPM DPR and ERA5
Effects of radiative cooling on advection fog over the northwest Pacific Ocean: observations and large-eddy simulations
Evaluating the Wegener–Bergeron–Findeisen process in ICON in large-eddy mode with in situ observations from the CLOUDLAB project
Aerosol-induced closure of marine cloud cells: enhanced effects in the presence of precipitation
Impact of ice multiplication on the cloud electrification of a cold-season thunderstorm: a numerical case study
Developing a climatological simplification of aerosols to enter the cloud microphysics of a global climate model
Interactions between trade wind clouds and local forcings over the Great Barrier Reef: a case study using convection-permitting simulations
Variability in the properties of the distribution of the relative humidity with respect to ice: implications for contrail formation
Simulating the seeder–feeder impacts on cloud ice and precipitation over the Alps
Cloud response to co-condensation of water and organic vapors over the boreal forest
Distribution and morphology of non-persistent contrail and persistent contrail formation areas in ERA5
Connection of Surface Snowfall Bias to Cloud Phase Bias – Satellite Observations, ERA5, and CMIP6
Above-cloud concentrations of cloud condensation nuclei help to sustain some Arctic low-level clouds
Contrail formation on ambient aerosol particles for aircraft with hydrogen combustion: a box model trajectory study
Kevin Wolf, Nicolas Bellouin, Olivier Boucher, Susanne Rohs, and Yun Li
Atmos. Chem. Phys., 25, 157–181, https://doi.org/10.5194/acp-25-157-2025, https://doi.org/10.5194/acp-25-157-2025, 2025
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ERA5 atmospheric reanalysis and airborne in situ observations from IAGOS are compared in terms of the representation of the contrail formation potential and the presence of supersaturation. Differences are traced back to biases in ERA5 relative humidity fields. Those biases are addressed by applying a quantile mapping technique that significantly improved contrail estimation based on post-processed ERA5 data.
Marje Prank, Juha Tonttila, Xiaoxia Shang, Sami Romakkaniemi, and Tomi Raatikainen
Atmos. Chem. Phys., 25, 183–197, https://doi.org/10.5194/acp-25-183-2025, https://doi.org/10.5194/acp-25-183-2025, 2025
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Large primary bioparticles such as pollen can be abundant in the atmosphere. In humid conditions pollen can rupture and release a large number of fine sub-pollen particles (SPPs). The paper investigates what kind of birch pollen concentrations are needed for the pollen and SPPs to start playing a noticeable role in cloud processes and alter precipitation formation. In the studied cases only the largest observed pollen concentrations were able to noticeably alter the precipitation formation.
Luís Filipe Escusa dos Santos, Hannah C. Frostenberg, Alejandro Baró Pérez, Annica M. L. Ekman, Luisa Ickes, and Erik S. Thomson
Atmos. Chem. Phys., 25, 119–142, https://doi.org/10.5194/acp-25-119-2025, https://doi.org/10.5194/acp-25-119-2025, 2025
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The Arctic is experiencing enhanced surface warming. The observed decline in Arctic sea-ice extent is projected to lead to an increase in Arctic shipping activity, which may lead to further climatic feedbacks. Using an atmospheric model and results from marine engine experiments that focused on fuel sulfur content reduction and exhaust wet scrubbing, we investigate how ship exhaust particles influence the properties of Arctic clouds. Implications for radiative surface processes are discussed.
Nadja Omanovic, Brigitta Goger, and Ulrike Lohmann
Atmos. Chem. Phys., 24, 14145–14175, https://doi.org/10.5194/acp-24-14145-2024, https://doi.org/10.5194/acp-24-14145-2024, 2024
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We evaluated the numerical weather model ICON in two horizontal resolutions with two bulk microphysics schemes over hilly and complex terrain in Switzerland and Austria, respectively. We focused on the model's ability to simulate mid-level clouds in summer and winter. By combining observational data from two different field campaigns, we show that an increase in the horizontal resolution and a more advanced cloud microphysics scheme is strongly beneficial for cloud representation.
Cornelis Schwenk and Annette Miltenberger
Atmos. Chem. Phys., 24, 14073–14099, https://doi.org/10.5194/acp-24-14073-2024, https://doi.org/10.5194/acp-24-14073-2024, 2024
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Warm conveyor belts (WCBs) transport moisture into the upper atmosphere, where it acts as a greenhouse gas. This transport is not well understood, and the role of rapidly rising air is unclear. We simulate a WCB and look at fast- and slow-rising air to see how moisture is (differently) transported. We find that for fast-ascending air more ice particles reach higher into the atmosphere and that frozen cloud particles are removed differently than during slow ascent, which has more water vapour.
Jing Yang, Jiaojiao Li, Meilian Chen, Xiaoqin Jing, Yan Yin, Bart Geerts, Zhien Wang, Yubao Liu, Baojun Chen, Shaofeng Hua, Hao Hu, Xiaobo Dong, Ping Tian, Qian Chen, and Yang Gao
Atmos. Chem. Phys., 24, 13833–13848, https://doi.org/10.5194/acp-24-13833-2024, https://doi.org/10.5194/acp-24-13833-2024, 2024
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Detecting unambiguous signatures is vital for examining cloud-seeding impacts, but often, seeding signatures are immersed in natural variability. In this study, reflectivity changes induced by glaciogenic seeding using different AgI concentrations are investigated under various conditions, and a method is developed to estimate the AgI concentration needed to detect unambiguous seeding signatures. The results aid in operational seeding-based decision-making regarding the amount of AgI dispersed.
Florian Sauerland, Niels Souverijns, Anna Possner, Heike Wex, Preben Van Overmeiren, Alexander Mangold, Kwinten Van Weverberg, and Nicole van Lipzig
Atmos. Chem. Phys., 24, 13751–13768, https://doi.org/10.5194/acp-24-13751-2024, https://doi.org/10.5194/acp-24-13751-2024, 2024
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We use a regional climate model, COSMO-CLM², enhanced with a module resolving aerosol processes, to study Antarctic clouds. We prescribe different concentrations of ice-nucleating particles to our model to assess how these clouds respond to concentration changes, validating results with cloud and aerosol observations from the Princess Elisabeth Antarctica station. Our results show that aerosol–cloud interactions vary with temperature, providing valuable insights into Antarctic cloud dynamics.
Yi Li, Xiaoli Liu, and Hengjia Cai
Atmos. Chem. Phys., 24, 13525–13540, https://doi.org/10.5194/acp-24-13525-2024, https://doi.org/10.5194/acp-24-13525-2024, 2024
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The influence of different aerosol modes on cloud processes remains controversial. We modified the aerosol spectra and concentrations to simulate a warm stratiform cloud process in Jiangxi, China, using the WRF-SBM scheme. Research shows that different aerosol spectra have diverse effects on cloud droplet spectra, cloud development, and the correlation between dispersion (ε) and cloud physics quantities. Compared to cloud droplet concentration, ε is more sensitive to the volume radius.
Fabian Hoffmann, Franziska Glassmeier, and Graham Feingold
Atmos. Chem. Phys., 24, 13403–13412, https://doi.org/10.5194/acp-24-13403-2024, https://doi.org/10.5194/acp-24-13403-2024, 2024
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Clouds constitute a major cooling influence on Earth's climate system by reflecting a large fraction of the incident solar radiation back to space. This ability is controlled by the number of cloud droplets, which is governed by the number of aerosol particles in the atmosphere, laying the foundation for so-called aerosol–cloud–climate interactions. In this study, a simple model to understand the effect of aerosol on cloud water is developed and applied.
Andrea Mosso, Thomas Hocking, and Thorsten Mauritsen
Atmos. Chem. Phys., 24, 12793–12806, https://doi.org/10.5194/acp-24-12793-2024, https://doi.org/10.5194/acp-24-12793-2024, 2024
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Clouds play a crucial role in the Earth's energy balance, as they can either warm up or cool down the area they cover depending on their height and depth. They are expected to alter their behaviour under climate change, affecting the warming generated by greenhouse gases. This paper proposes a new method to estimate their overall effect on this warming by simulating a climate where clouds are transparent. Results show that with the model used, clouds have a stabilising effect on climate.
Tao Shi, Yuanjian Yang, Ping Qi, and Simone Lolli
Atmos. Chem. Phys., 24, 12807–12822, https://doi.org/10.5194/acp-24-12807-2024, https://doi.org/10.5194/acp-24-12807-2024, 2024
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This paper explored the formation mechanisms of the amplified canopy urban heat island intensity (ΔCUHII) during heat wave (HW) periods in the megacity of Beijing from the perspectives of mountain–valley breeze and urban morphology. During the mountain breeze phase, high-rise buildings with lower sky view factors (SVFs) had a pronounced effect on the ΔCUHII. During the valley breeze phase, high-rise buildings exerted a dual influence on the ΔCUHII.
Yao-Sheng Chen, Jianhao Zhang, Fabian Hoffmann, Takanobu Yamaguchi, Franziska Glassmeier, Xiaoli Zhou, and Graham Feingold
Atmos. Chem. Phys., 24, 12661–12685, https://doi.org/10.5194/acp-24-12661-2024, https://doi.org/10.5194/acp-24-12661-2024, 2024
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Marine stratocumulus cloud is a type of shallow cloud that covers the vast areas of Earth's surface. It plays an important role in Earth's energy balance by reflecting solar radiation back to space. We used numerical models to simulate a large number of marine stratocumuli with different characteristics. We found that how the clouds develop throughout the day is affected by the level of humidity in the air above the clouds and how closely the clouds connect to the ocean surface.
Alexei Korolev, Zhipeng Qu, Jason Milbrandt, Ivan Heckman, Mélissa Cholette, Mengistu Wolde, Cuong Nguyen, Greg M. McFarquhar, Paul Lawson, and Ann M. Fridlind
Atmos. Chem. Phys., 24, 11849–11881, https://doi.org/10.5194/acp-24-11849-2024, https://doi.org/10.5194/acp-24-11849-2024, 2024
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The phenomenon of high ice water content (HIWC) occurs in mesoscale convective systems (MCSs) when a large number of small ice particles with typical sizes of a few hundred micrometers is found at high altitudes. It was found that secondary ice production in the vicinity of the melting layer plays a key role in the formation and maintenance of HIWC. This study presents a conceptual model of the formation of HIWC in tropical MCSs based on in situ observations and numerical simulation.
Puja Roy, Robert M. Rauber, and Larry Di Girolamo
Atmos. Chem. Phys., 24, 11653–11678, https://doi.org/10.5194/acp-24-11653-2024, https://doi.org/10.5194/acp-24-11653-2024, 2024
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Cloud droplet temperature and lifetime impact cloud microphysical processes such as the activation of ice-nucleating particles. We investigate the thermal and radial evolution of supercooled cloud droplets and their surrounding environments with an aim to better understand observed enhanced ice formation at supercooled cloud edges. This analysis shows that the magnitude of droplet cooling during evaporation is greater than estimated from past studies, especially for drier environments.
Mathieu Lachapelle, Mélissa Cholette, and Julie M. Thériault
Atmos. Chem. Phys., 24, 11285–11304, https://doi.org/10.5194/acp-24-11285-2024, https://doi.org/10.5194/acp-24-11285-2024, 2024
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Hazardous precipitation types such as ice pellets and freezing rain are difficult to predict because they are associated with complex microphysical processes. Using Predicted Particle Properties (P3), this work shows that secondary ice production processes increase the amount of ice pellets simulated while decreasing the amount of freezing rain. Moreover, the properties of the simulated precipitation compare well with those that were measured.
Andrew DeLaFrance, Lynn A. McMurdie, Angela K. Rowe, and Andrew J. Heymsfield
Atmos. Chem. Phys., 24, 11191–11206, https://doi.org/10.5194/acp-24-11191-2024, https://doi.org/10.5194/acp-24-11191-2024, 2024
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Using a numerical model, the process whereby falling ice crystals accumulate supercooled liquid water droplets is investigated to elucidate its effects on radar-based measurements and surface precipitation. We demonstrate that this process accounted for 55% of the precipitation during a wintertime storm and is uniquely discernable from other ice crystal growth processes in Doppler velocity measurements. These results have implications for measurements from airborne and spaceborne platforms.
Toshi Matsui, Daniel Hernandez-Deckers, Scott E. Giangrande, Thiago S. Biscaro, Ann Fridlind, and Scott Braun
Atmos. Chem. Phys., 24, 10793–10814, https://doi.org/10.5194/acp-24-10793-2024, https://doi.org/10.5194/acp-24-10793-2024, 2024
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Using computer simulations and real measurements, we discovered that storms over the Amazon were narrower but more intense during the dry periods, producing heavier rain and more ice particles in the clouds. Our research showed that cumulus bubbles played a key role in creating these intense storms. This study can improve the representation of the effect of continental and ocean environments on tropical regions' rainfall patterns in simulations.
Ravi Kumar Reddy Addula, Ingrid de Almeida Ribeiro, Valeria Molinero, and Baron Peters
Atmos. Chem. Phys., 24, 10833–10848, https://doi.org/10.5194/acp-24-10833-2024, https://doi.org/10.5194/acp-24-10833-2024, 2024
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Ice nucleation from supercooled droplets is important in many weather and climate modeling efforts. For experiments where droplets are steadily supercooled from the freezing point, our work combines nucleation theory and survival probability analysis to predict the nucleation spectrum, i.e., droplet freezing probabilities vs. temperature. We use the new framework to extract approximately consistent rate parameters from experiments with different cooling rates and droplet sizes.
Jianhao Zhang, Yao-Sheng Chen, Takanobu Yamaguchi, and Graham Feingold
Atmos. Chem. Phys., 24, 10425–10440, https://doi.org/10.5194/acp-24-10425-2024, https://doi.org/10.5194/acp-24-10425-2024, 2024
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Quantifying cloud response to aerosol perturbations presents a major challenge in understanding the human impact on climate. Using a large number of process-resolving simulations of marine stratocumulus, we show that solar heating drives a negative feedback mechanism that buffers the persistent negative trend in cloud water adjustment after sunrise. This finding has implications for the dependence of the cloud cooling effect on the timing of deliberate aerosol perturbations.
Aaron Wang, Steve Krueger, Sisi Chen, Mikhail Ovchinnikov, Will Cantrell, and Raymond A. Shaw
Atmos. Chem. Phys., 24, 10245–10260, https://doi.org/10.5194/acp-24-10245-2024, https://doi.org/10.5194/acp-24-10245-2024, 2024
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We employ two methods to examine a laboratory experiment on clouds with both ice and liquid phases. The first assumes well-mixed properties; the second resolves the spatial distribution of turbulence and cloud particles. Results show that while the trends in mean properties generally align, when turbulence is resolved, liquid droplets are not fully depleted by ice due to incomplete mixing. This underscores the threshold of ice mass fraction in distinguishing mixed-phase clouds from ice clouds.
Theresa Kiszler, Davide Ori, and Vera Schemann
Atmos. Chem. Phys., 24, 10039–10053, https://doi.org/10.5194/acp-24-10039-2024, https://doi.org/10.5194/acp-24-10039-2024, 2024
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Microphysical processes impact the phase-partitioning of clouds. In this study we evaluate these processes while focusing on low-level Arctic clouds. To achieve this we used an extensive simulation set in combination with a new diagnostic tool. This study presents our findings on the relevance of these processes and their behaviour under different thermodynamic regimes.
Shuaiqi Tang, Hailong Wang, Xiang-Yu Li, Jingyi Chen, Armin Sorooshian, Xubin Zeng, Ewan Crosbie, Kenneth L. Thornhill, Luke D. Ziemba, and Christiane Voigt
Atmos. Chem. Phys., 24, 10073–10092, https://doi.org/10.5194/acp-24-10073-2024, https://doi.org/10.5194/acp-24-10073-2024, 2024
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We examined marine boundary layer clouds and their interactions with aerosols in the E3SM single-column model (SCM) for a case study. The SCM shows good agreement when simulating the clouds with high-resolution models. It reproduces the relationship between cloud droplet and aerosol particle number concentrations as produced in global models. However, the relationship between cloud liquid water and droplet number concentration is different, warranting further investigation.
Tim Lüttmer, Peter Spichtinger, and Axel Seifert
EGUsphere, https://doi.org/10.5194/egusphere-2024-2157, https://doi.org/10.5194/egusphere-2024-2157, 2024
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We investigate ice formation pathways in idealized convective clouds using a novel microphysics scheme, that distinguishes between five ice classes each with their unique formation mechanism. Ice crystals from rime splintering forms the lowermost layer of ice crystals around the updraft core. The majority of ice crystals in the anvil of the convective cloud stems from frozen droplets. Ice stemming from homogeneous and deposition nucleation was only relevant in the overshoot.
Suf Lorian and Guy Dagan
Atmos. Chem. Phys., 24, 9323–9338, https://doi.org/10.5194/acp-24-9323-2024, https://doi.org/10.5194/acp-24-9323-2024, 2024
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We examine the combined effect of aerosols and sea surface temperature (SST) on clouds under equilibrium conditions in cloud-resolving radiative–convective equilibrium simulations. We demonstrate that the aerosol–cloud interaction's effect on top-of-atmosphere energy gain strongly depends on the underlying SST, while the shortwave part of the spectrum is significantly more sensitive to SST. Furthermore, increasing aerosols influences upper-troposphere stability and thus anvil cloud fraction.
Jianqi Zhao, Xiaoyan Ma, Johannes Quaas, and Hailing Jia
Atmos. Chem. Phys., 24, 9101–9118, https://doi.org/10.5194/acp-24-9101-2024, https://doi.org/10.5194/acp-24-9101-2024, 2024
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We explore aerosol–cloud interactions in liquid-phase clouds over eastern China and its adjacent ocean in winter based on the WRF-Chem–SBM model, which couples a spectral-bin microphysics scheme and an online aerosol module. Our study highlights the differences in aerosol–cloud interactions between land and ocean and between precipitation clouds and non-precipitation clouds, and it differentiates and quantifies their underlying mechanisms.
Ann Kristin Naumann, Monika Esch, and Bjorn Stevens
EGUsphere, https://doi.org/10.5194/egusphere-2024-2268, https://doi.org/10.5194/egusphere-2024-2268, 2024
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This study explores how uncertainties in the representation of microphysical processes affect the tropical condensate distribution in the global storm-resolving model ICON. The results point to the importance of the fall speed of hydrometeor particles and to a simple relationship: the faster a condensate falls, the less there is of it. Implications for the energy balance and precipitation properties are discussed.
Shiye Huang, Jing Yang, Qian Chen, Jiaojiao Li, Qilin Zhang, and Fengxia Guo
EGUsphere, https://doi.org/10.5194/egusphere-2024-2013, https://doi.org/10.5194/egusphere-2024-2013, 2024
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Aerosol and secondary ice production are both vital to charge separation in thunderstorms, but the relative importance of different SIP processes to cloud electrification under different aerosol conditions is not well understood. In this study, we show in a clean environment, the shattering of freezing drops has the greatest effect on the charging rate, while in a polluted environment, both rime splintering and the shattering of freezing drops have a significant effect on cloud electrification.
Thomas D. DeWitt and Timothy J. Garrett
Atmos. Chem. Phys., 24, 8457–8472, https://doi.org/10.5194/acp-24-8457-2024, https://doi.org/10.5194/acp-24-8457-2024, 2024
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There is considerable disagreement on mathematical parameters that describe the number of clouds of different sizes as well as the size of the largest clouds. Both are key defining characteristics of Earth's atmosphere. A previous study provided an incorrect explanation for the disagreement. Instead, the disagreement may be explained by prior studies not properly accounting for the size of their measurement domain. We offer recommendations for how the domain size can be accounted for.
Sarah Wilson Kemsley, Paulo Ceppi, Hendrik Andersen, Jan Cermak, Philip Stier, and Peer Nowack
Atmos. Chem. Phys., 24, 8295–8316, https://doi.org/10.5194/acp-24-8295-2024, https://doi.org/10.5194/acp-24-8295-2024, 2024
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Aiming to inform parameter selection for future observational constraint analyses, we incorporate five candidate meteorological drivers specifically targeting high clouds into a cloud controlling factor framework within a range of spatial domain sizes. We find a discrepancy between optimal domain size for predicting locally and globally aggregated cloud radiative anomalies and identify upper-tropospheric static stability as an important high-cloud controlling factor.
Ye Liu, Yun Qian, Larry K. Berg, Zhe Feng, Jianfeng Li, Jingyi Chen, and Zhao Yang
Atmos. Chem. Phys., 24, 8165–8181, https://doi.org/10.5194/acp-24-8165-2024, https://doi.org/10.5194/acp-24-8165-2024, 2024
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Deep convection under various large-scale meteorological patterns (LSMPs) shows distinct precipitation features. In southeastern Texas, mesoscale convective systems (MCSs) contribute significantly to precipitation year-round, while isolated deep convection (IDC) is prominent in summer and fall. Self-organizing maps (SOMs) reveal convection can occur without large-scale lifting or moisture convergence. MCSs and IDC events have distinct life cycles influenced by specific LSMPs.
Xiaoran Guo, Jianping Guo, Tianmeng Chen, Ning Li, Fan Zhang, and Yuping Sun
Atmos. Chem. Phys., 24, 8067–8083, https://doi.org/10.5194/acp-24-8067-2024, https://doi.org/10.5194/acp-24-8067-2024, 2024
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The prediction of downhill thunderstorms (DSs) remains elusive. We propose an objective method to identify DSs, based on which enhanced and dissipated DSs are discriminated. A radar wind profiler (RWP) mesonet is used to derive divergence and vertical velocity. The mid-troposphere divergence and prevailing westerlies enhance the intensity of DSs, whereas low-level divergence is observed when the DS dissipates. The findings highlight the key role that an RWP mesonet plays in the evolution of DSs.
Sina Hofer, Klaus Gierens, and Susanne Rohs
Atmos. Chem. Phys., 24, 7911–7925, https://doi.org/10.5194/acp-24-7911-2024, https://doi.org/10.5194/acp-24-7911-2024, 2024
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We try to improve the forecast of ice supersaturation (ISS) and potential persistent contrails using data on dynamical quantities in addition to temperature and relative humidity in a modern kind of regression model. Although the results are improved, they are not good enough for flight routing. The origin of the problem is the strong overlap of probability densities conditioned on cases with and without ice-supersaturated regions (ISSRs) in the important range of 70–100 %.
Harri Kokkola, Juha Tonttila, Silvia Calderón, Sami Romakkaniemi, Antti Lipponen, Aapo Peräkorpi, Tero Mielonen, Edward Gryspeerdt, Timo H. Virtanen, Pekka Kolmonen, and Antti Arola
EGUsphere, https://doi.org/10.5194/egusphere-2024-1964, https://doi.org/10.5194/egusphere-2024-1964, 2024
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Understanding how atmospheric aerosols affect clouds is a scientific challenge. One question is how aerosols affects the amount cloud water. We used a cloud-scale model to study these effects on marine clouds. The study showed that variations in cloud properties and instrument noise can cause bias in satellite derived cloud water content. However, our results suggest that for similar weather conditions with well-defined aerosol concentrations, satellite data can reliably track these effects.
Claudia Christine Stephan and Bjorn Stevens
EGUsphere, https://doi.org/10.5194/egusphere-2024-2020, https://doi.org/10.5194/egusphere-2024-2020, 2024
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Tropical precipitation cluster area and intensity distributions follow power laws, but the physical processes responsible for this behavior remain unknown. We analyze global simulations that realistically represent precipitation processes. We consider Earth-like planets as well as virtual planets to realize different types of large-scale dynamics. Our finding is that power laws in Earth’s precipitation cluster statistics stem from the robust power laws in Earth’s atmospheric wind field.
Naser Mahfouz, Johannes Mülmenstädt, and Susannah Burrows
Atmos. Chem. Phys., 24, 7253–7260, https://doi.org/10.5194/acp-24-7253-2024, https://doi.org/10.5194/acp-24-7253-2024, 2024
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Climate models are our primary tool to probe past, present, and future climate states unlike the more recent observation record. By constructing a hypothetical model configuration, we show that present-day correlations are insufficient to predict a persistent uncertainty in climate projection (how much sun because clouds will reflect in a changing climate). We hope our result will contribute to the scholarly conversation on better utilizing observations to constrain climate uncertainties.
Britta Schäfer, Robert Oscar David, Paraskevi Georgakaki, Julie Thérèse Pasquier, Georgia Sotiropoulou, and Trude Storelvmo
Atmos. Chem. Phys., 24, 7179–7202, https://doi.org/10.5194/acp-24-7179-2024, https://doi.org/10.5194/acp-24-7179-2024, 2024
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Mixed-phase clouds, i.e., clouds consisting of ice and supercooled water, are very common in the Arctic. However, how these clouds form is often not correctly represented in standard weather models. We show that both ice crystal concentrations in the cloud and precipitation from the cloud can be improved in the model when aerosol concentrations are prescribed from observations and when more processes for ice multiplication, i.e., the production of new ice particles from existing ice, are added.
Nan Sun, Gaopeng Lu, and Yunfei Fu
Atmos. Chem. Phys., 24, 7123–7135, https://doi.org/10.5194/acp-24-7123-2024, https://doi.org/10.5194/acp-24-7123-2024, 2024
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Microphysical characteristics of convective overshooting are essential but poorly understood, and we examine them by using the latest data. (1) Convective overshooting events mainly occur over NC (Northeast China) and northern MEC (Middle and East China). (2) Radar reflectivity of convective overshooting over NC accounts for a higher proportion below the zero level, while the opposite is the case for MEC and SC (South China). (3) Droplets of convective overshooting are large but sparse.
Liu Yang, Saisai Ding, Jing-Wu Liu, and Su-Ping Zhang
Atmos. Chem. Phys., 24, 6809–6824, https://doi.org/10.5194/acp-24-6809-2024, https://doi.org/10.5194/acp-24-6809-2024, 2024
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Advection fog occurs when warm and moist air moves over a cold sea surface. In this situation, the temperature of the foggy air usually drops below the sea surface temperature (SST), particularly at night. High-resolution simulations show that the cooling effect of longwave radiation from the top of the fog layer permeates through the fog, resulting in a cooling of the surface air below SST. This study emphasizes the significance of monitoring air temperature to enhance sea fog forecasting.
Nadja Omanovic, Sylvaine Ferrachat, Christopher Fuchs, Jan Henneberger, Anna J. Miller, Kevin Ohneiser, Fabiola Ramelli, Patric Seifert, Robert Spirig, Huiying Zhang, and Ulrike Lohmann
Atmos. Chem. Phys., 24, 6825–6844, https://doi.org/10.5194/acp-24-6825-2024, https://doi.org/10.5194/acp-24-6825-2024, 2024
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We present simulations with a high-resolution numerical weather prediction model to study the growth of ice crystals in low clouds following glaciogenic seeding. We show that the simulated ice crystals grow slower than observed and do not consume as many cloud droplets as measured in the field. This may have implications for forecasting precipitation, as the ice phase is crucial for precipitation at middle and high latitudes.
Matthew W. Christensen, Peng Wu, Adam C. Varble, Heng Xiao, and Jerome D. Fast
Atmos. Chem. Phys., 24, 6455–6476, https://doi.org/10.5194/acp-24-6455-2024, https://doi.org/10.5194/acp-24-6455-2024, 2024
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Clouds are essential to keep Earth cooler by reflecting sunlight back to space. We show that an increase in aerosol concentration suppresses precipitation in clouds, causing them to accumulate water and expand in a polluted environment with stronger turbulence and radiative cooling. This process enhances their reflectance by 51 %. It is therefore prudent to account for cloud fraction changes in assessments of aerosol–cloud interactions to improve predictions of climate change.
Jing Yang, Shiye Huang, Tianqi Yang, Qilin Zhang, Yuting Deng, and Yubao Liu
Atmos. Chem. Phys., 24, 5989–6010, https://doi.org/10.5194/acp-24-5989-2024, https://doi.org/10.5194/acp-24-5989-2024, 2024
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This study contributes to filling the dearth of understanding the impacts of different secondary ice production (SIP) processes on the cloud electrification in cold-season thunderstorms. The results suggest that SIP, especially the rime-splintering process and the shattering of freezing drops, has significant impacts on the charge structure of the storm. In addition, the modeled radar composite reflectivity and flash rate are improved after implementing the SIP processes in the model.
Ulrike Proske, Sylvaine Ferrachat, and Ulrike Lohmann
Atmos. Chem. Phys., 24, 5907–5933, https://doi.org/10.5194/acp-24-5907-2024, https://doi.org/10.5194/acp-24-5907-2024, 2024
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Climate models include treatment of aerosol particles because these influence clouds and radiation. Over time their representation has grown increasingly detailed. This complexity may hinder our understanding of model behaviour. Thus here we simplify the aerosol representation of our climate model by prescribing mean concentrations, which saves run time and helps to discover unexpected model behaviour. We conclude that simplifications provide a new perspective for model study and development.
Wenhui Zhao, Yi Huang, Steven Siems, Michael Manton, and Daniel Harrison
Atmos. Chem. Phys., 24, 5713–5736, https://doi.org/10.5194/acp-24-5713-2024, https://doi.org/10.5194/acp-24-5713-2024, 2024
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We studied how shallow clouds and rain behave over the Great Barrier Reef (GBR) using a detailed weather model. We found that the shape of the land, especially mountains, and particles in the air play big roles in influencing these clouds. Surprisingly, the sea's temperature had a smaller effect. Our research helps us understand the GBR's climate and how various factors can influence it, where the importance of the local cloud in thermal coral bleaching has recently been identified.
Sidiki Sanogo, Olivier Boucher, Nicolas Bellouin, Audran Borella, Kevin Wolf, and Susanne Rohs
Atmos. Chem. Phys., 24, 5495–5511, https://doi.org/10.5194/acp-24-5495-2024, https://doi.org/10.5194/acp-24-5495-2024, 2024
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Relative humidity relative to ice (RHi) is a key variable in the formation of cirrus clouds and contrails. This study shows that the properties of the probability density function of RHi differ between the tropics and higher latitudes. In line with RHi and temperature variability, aircraft are likely to produce more contrails with bioethanol and liquid hydrogen as fuel. The impact of this fuel change decreases with decreasing pressure levels but increases from high latitudes to the tropics.
Zane Dedekind, Ulrike Proske, Sylvaine Ferrachat, Ulrike Lohmann, and David Neubauer
Atmos. Chem. Phys., 24, 5389–5404, https://doi.org/10.5194/acp-24-5389-2024, https://doi.org/10.5194/acp-24-5389-2024, 2024
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Ice particles precipitating into lower clouds from an upper cloud, the seeder–feeder process, can enhance precipitation. A numerical modeling study conducted in the Swiss Alps found that 48 % of observed clouds were overlapping, with the seeder–feeder process occurring in 10 % of these clouds. Inhibiting the seeder–feeder process reduced the surface precipitation and ice particle growth rates, which were further reduced when additional ice multiplication processes were included in the model.
Liine Heikkinen, Daniel G. Partridge, Sara Blichner, Wei Huang, Rahul Ranjan, Paul Bowen, Emanuele Tovazzi, Tuukka Petäjä, Claudia Mohr, and Ilona Riipinen
Atmos. Chem. Phys., 24, 5117–5147, https://doi.org/10.5194/acp-24-5117-2024, https://doi.org/10.5194/acp-24-5117-2024, 2024
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The organic vapor condensation with water vapor (co-condensation) in rising air below clouds is modeled in this work over the boreal forest because the forest air is rich in organic vapors. We show that the number of cloud droplets can increase by 20 % if considering co-condensation. The enhancements are even larger if the air contains many small, naturally produced aerosol particles. Such conditions are most frequently met in spring in the boreal forest.
Kevin Wolf, Nicolas Bellouin, and Olivier Boucher
Atmos. Chem. Phys., 24, 5009–5024, https://doi.org/10.5194/acp-24-5009-2024, https://doi.org/10.5194/acp-24-5009-2024, 2024
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The contrail formation potential and its tempo-spatial distribution are estimated for the North Atlantic flight corridor. Meteorological conditions of temperature and relative humidity are taken from the ERA5 re-analysis and IAGOS. Based on IAGOS flight tracks, crossing length, size, orientation, frequency of occurrence, and overlap of persistent contrail formation areas are determined. The presented conclusions might provide a guide for statistical flight track optimization to reduce contrails.
Franziska Hellmuth, Tim Carlsen, Anne Sophie Daloz, Robert Oscar David, and Trude Storelvmo
EGUsphere, https://doi.org/10.5194/egusphere-2024-754, https://doi.org/10.5194/egusphere-2024-754, 2024
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This article compares the occurrence of supercooled liquid-containing clouds (sLCCs) and their link to surface snowfall in CloudSat-CALIPSO, ERA5, and CMIP6 models. Significant discrepancies were found, with ERA5 and CMIP6 consistently overestimating sLCC and snowfall frequency. This bias is likely due to cloud microphysics parameterization. This conclusion has implications for accurately representing cloud phase and snowfall in future climate projections.
Lucas J. Sterzinger and Adele L. Igel
Atmos. Chem. Phys., 24, 3529–3540, https://doi.org/10.5194/acp-24-3529-2024, https://doi.org/10.5194/acp-24-3529-2024, 2024
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Using idealized large eddy simulations, we find that clouds forming in the Arctic in environments with low concentrations of aerosol particles may be sustained by mixing in new particles through the cloud top. Observations show that higher concentrations of these particles regularly exist above cloud top in concentrations that are sufficient to promote this sustenance.
Andreas Bier, Simon Unterstrasser, Josef Zink, Dennis Hillenbrand, Tina Jurkat-Witschas, and Annemarie Lottermoser
Atmos. Chem. Phys., 24, 2319–2344, https://doi.org/10.5194/acp-24-2319-2024, https://doi.org/10.5194/acp-24-2319-2024, 2024
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Using hydrogen as aviation fuel affects contrails' climate impact. We study contrail formation behind aircraft with H2 combustion. Due to the absence of soot emissions, contrail ice crystals are assumed to form only on ambient particles mixed into the plume. The ice crystal number, which strongly varies with temperature and aerosol number density, is decreased by more than 80 %–90 % compared to kerosene contrails. However H2 contrails can form at lower altitudes due to higher H2O emissions.
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Short summary
This paper assesses the reasons for high ice number concentrations observed in orographic clouds by comparing observations with model simulations over Jungfraujoch, Switzerland. The results suggest that ice nuclei do not significantly contribute to the high concentrations and that a surface source of ice crystals is responsible for the witnessed ice number concentrations.
This paper assesses the reasons for high ice number concentrations observed in orographic clouds...
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