Articles | Volume 18, issue 15
Atmos. Chem. Phys., 18, 11041–11071, 2018
https://doi.org/10.5194/acp-18-11041-2018
© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Special issue: BACCHUS – Impact of Biogenic versus Anthropogenic emissions...
Atmos. Chem. Phys., 18, 11041–11071, 2018
https://doi.org/10.5194/acp-18-11041-2018
© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article 08 Aug 2018
Research article | 08 Aug 2018
A model intercomparison of CCN-limited tenuous clouds in the high Arctic
Robin G. Stevens et al.
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Kimiko M. Sakamoto, James R. Laing, Robin G. Stevens, Daniel A. Jaffe, and Jeffrey R. Pierce
Atmos. Chem. Phys., 16, 7709–7724, https://doi.org/10.5194/acp-16-7709-2016, https://doi.org/10.5194/acp-16-7709-2016, 2016
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We determine how various meteorological and fire factors contribute to shaping the aged biomass-burning particle size distribution through coagulation. The mass emissions flux, fire area, and wind speed are dominant factors controlling the aged size distribution. We parameterize the aged size distribution for global/regional aerosol models. We estimate that the aged biomass-burning particle size distribution may be more sensitive to variability in coagulation than SOA formation.
R. G. Stevens and J. R. Pierce
Atmos. Chem. Phys., 14, 13661–13679, https://doi.org/10.5194/acp-14-13661-2014, https://doi.org/10.5194/acp-14-13661-2014, 2014
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We implement a parameterization of sub-grid new-particle formation in sulfur-rich plumes (P6) for the first time into a global chemical-transport model with online aerosol microphysics. Compared with previous treatments of sub-grid particle formation, use of the P6 parameterization limits sub-grid particle formation in polluted or low-sunlight regions. We also test the sensitivity of sub-grid particle formation to changes in SO2 or NOx emissions due to emissions controls.
R. G. Stevens and J. R. Pierce
Atmos. Chem. Phys., 13, 12117–12133, https://doi.org/10.5194/acp-13-12117-2013, https://doi.org/10.5194/acp-13-12117-2013, 2013
G. S. Stuart, R. G. Stevens, A.-I. Partanen, A. K. L. Jenkins, H. Korhonen, P. M. Forster, D. V. Spracklen, and J. R. Pierce
Atmos. Chem. Phys., 13, 10385–10396, https://doi.org/10.5194/acp-13-10385-2013, https://doi.org/10.5194/acp-13-10385-2013, 2013
Kimmo Korhonen, Thomas Bjerring Kristensen, John Falk, Vilhelm B. Malmborg, Axel Eriksson, Louise Gren, Maja Novakovic, Sam Shamun, Panu Karjalainen, Lassi Markkula, Joakim Pagels, Birgitta Svenningsson, Martin Tunér, Mika Komppula, Ari Laaksonen, and Annele Virtanen
Atmos. Chem. Phys. Discuss., https://doi.org/10.5194/acp-2021-111, https://doi.org/10.5194/acp-2021-111, 2021
Preprint under review for ACP
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We investigated the ice-nucleating abilities of particulate emissions from a modern diesel engine using portable ice-nuclei counter SPIN, a continuous flow diffusion chamber instrument. Three different fuels were studied without blending, including fossil diesel and two renewable fuels, testing different emission aftertreatment systems and photochemical aging. We found that the diesel emissions were inefficient ice-nuclei, and aging had only no or little effect on their ice-nucleating abilities.
Kamalika Sengupta, Kirsty Pringle, Jill S. Johnson, Carly Reddington, Jo Browse, Catherine E. Scott, and Ken Carslaw
Atmos. Chem. Phys., 21, 2693–2723, https://doi.org/10.5194/acp-21-2693-2021, https://doi.org/10.5194/acp-21-2693-2021, 2021
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Global models consistently underestimate atmospheric secondary organic aerosol (SOA), which has significant climatic implications. We use a perturbed parameter model ensemble and ground-based observations to reduce the uncertainty in modelling SOA formation from oxidation of volatile organic compounds. We identify plausible parameter spaces for the yields of extremely low-volatility, low-volatility, and semi-volatile organic compounds based on model–observation match for three key model outputs.
Zane Dedekind, Annika Lauber, Sylvaine Ferrachat, and Ulrike Lohmann
Atmos. Chem. Phys. Discuss., https://doi.org/10.5194/acp-2020-1326, https://doi.org/10.5194/acp-2020-1326, 2021
Preprint under review for ACP
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The RACLETS campaign combined cloud and snow research to improve the understanding of precipitation formation in clouds. A numerical weather prediction model, COSMO, was used to assess the importance of ice crystal enhancement by ice-ice collisions on cloud properties. We found that the number of ice crystals increased 1 to 3 orders of magnitude when ice-ice collisions were permitted to occur reducing localized regions of high precipitation and thereby improving the model performance.
Ana A. Piedehierro, André Welti, Angela Buchholtz, Kimmo Korhonen, Iida Pullinen, Ilkka Summanen, Annele Virtanen, and Ari Laaksonen
Atmos. Chem. Phys. Discuss., https://doi.org/10.5194/acp-2021-10, https://doi.org/10.5194/acp-2021-10, 2021
Preprint under review for ACP
Antti Ruuskanen, Sami Romakkaniemi, Harri Kokkola, Antti Arola, Santtu Mikkonen, Harri Portin, Annele Virtanen, Kari E. J. Lehtinen, Mika Komppula, and Ari Leskinen
Atmos. Chem. Phys., 21, 1683–1695, https://doi.org/10.5194/acp-21-1683-2021, https://doi.org/10.5194/acp-21-1683-2021, 2021
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The study focuses mainly on cloud-scavenging efficiency of absorbing particulate matter (mainly black carbon) but additionally covers cloud-scavenging efficiency of scattering particles and statistics of cloud condensation nuclei. The main findings give insight into how black carbon is distributed in different particle sizes and the sensitivity to cloud scavenged. The main findings are useful for large-scale modelling for evaluating cloud scavenging.
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.
Juha Tonttila, Ali Afzalifar, Harri Kokkola, Tomi Raatikainen, Hannele Korhonen, and Sami Romakkaniemi
Atmos. Chem. Phys., 21, 1035–1048, https://doi.org/10.5194/acp-21-1035-2021, https://doi.org/10.5194/acp-21-1035-2021, 2021
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The focus of this study is on rain enhancement by deliberate injection of small particles into clouds (
cloud seeding). The particles, usually released from an aircraft, are expected to enhance cloud droplet growth, but its practical feasibility is somewhat uncertain. To improve upon this, we simulate the seeding effects with a numerical model. The model reproduces the main features seen in field observations, with a strong sensitivity to the total mass of the injected particle material.
Mao Xiao, Christopher R. Hoyle, Lubna Dada, Dominik Stolzenburg, Andreas Kürten, Mingyi Wang, Houssni Lamkaddam, Olga Garmash, Bernhard Mentler, Ugo Molteni, Andrea Baccarini, Mario Simon, Xu-Cheng He, Katrianne Lehtipalo, Lauri R. Ahonen, Rima Baalbaki, Paulus S. Bauer, Lisa Beck, David Bell, Federico Bianchi, Sophia Brilke, Dexian Chen, Randall Chiu, António Dias, Jonathan Duplissy, Henning Finkenzeller, Hamish Gordon, Victoria Hofbauer, Changhyuk Kim, Theodore K. Koenig, Janne Lampilahti, Chuan Ping Lee, Zijun Li, Huajun Mai, Vladimir Makhmutov, Hanna E. Manninen, Ruby Marten, Serge Mathot, Roy L. Mauldin, Wei Nie, Antti Onnela, Eva Partoll, Tuukka Petäjä, Joschka Pfeifer, Veronika Pospisilova, Lauriane L. J. Quéléver, Matti Rissanen, Siegfried Schobesberger, Simone Schuchmann, Yuri Stozhkov, Christian Tauber, Yee Jun Tham, António Tomé, Miguel Vazquez-Pufleau, Andrea C. Wagner, Robert Wanger, Yonghong Wang, Lena Weitz, Daniela Wimmer, Yusheng Wu, Chao Yan, Penglin Ye, Qing Ye, Qiaozhi Zha, Xueqin Zhou, Antonio Amorim, Ken Carslaw, Joachim Curtius, Armin Hansel, Rainer Volkamer, Paul M. Winkler, Richard C. Flagan, Markku Kulmala, Douglas R. Worsnop, Jasper Kirkby, Neil M. Donahue, Urs Baltensperger, Imad El Haddad, and Josef Dommen
Atmos. Chem. Phys. Discuss., https://doi.org/10.5194/acp-2020-1323, https://doi.org/10.5194/acp-2020-1323, 2021
Preprint under review for ACP
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Experiments at CLOUD show that in polluted environments new particle formation (NPF) is largely driven by the formation of sulfuric acid-base clusters, stabilized by amines, high ammonia concentrations or lower temperatures. While oxidation products of aromatics can nucleate, they play a minor role in urban NPF. Our experiments span the four orders of magnitude variation of observed NPF rates in the ambient. We provide a framework based on NPF and growth rates to interpret ambient observations.
Benjamin J. Murray, Kenneth S. Carslaw, and Paul R. Field
Atmos. Chem. Phys., 21, 665–679, https://doi.org/10.5194/acp-21-665-2021, https://doi.org/10.5194/acp-21-665-2021, 2021
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The balance between the amounts of ice and supercooled water in clouds over the world's oceans strongly influences how much these clouds can dampen or amplify global warming. Aerosol particles which catalyse ice formation can dramatically reduce the amount of supercooled water in clouds; hence we argue that we need a concerted effort to improve our understanding of these ice-nucleating particles if we are to improve our predictions of climate change.
Paolo Pelucchi, David Neubauer, and Ulrike Lohmann
Geosci. Model Dev. Discuss., https://doi.org/10.5194/gmd-2020-384, https://doi.org/10.5194/gmd-2020-384, 2021
Preprint under review for GMD
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Stratocumulus are thin clouds whose cloud cover is underestimated in climate models partly due to too-low vertical resolution. We develop a scheme that locally refines the vertical grid based on a physical constraint for the cloud top. Global simulations reveal that the scheme, implemented only in the radiation routine, can increase stratocumulus cloud cover. However, this effect is not propagated to the simulated cloud cover. The scheme could be more effective if implemented in other routines.
André Welti, Kimmo Korhonen, Pasi Miettinen, Ana A. Piedehierro, Yrjö Viisanen, Annele Virtanen, and Ari Laaksonen
Atmos. Meas. Tech., 13, 7059–7067, https://doi.org/10.5194/amt-13-7059-2020, https://doi.org/10.5194/amt-13-7059-2020, 2020
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We describe a modification of the SPectrometer for Ice Nuclei (SPIN) chamber to study ice nucleation at low temperatures, relevant for ice formation in cirrus clouds. Validation experiments of homogeneous freezing of aqueous ammonium sulfate droplets and heterogeneous ice nucleation on silver iodide particles are included to demonstrate the advantages of the modified SPIN chamber for the investigation of ice nucleation in the extended temperature range.
Jane P. Mulcahy, Colin Johnson, Colin G. Jones, Adam C. Povey, Catherine E. Scott, Alistair Sellar, Steven T. Turnock, Matthew T. Woodhouse, Nathan Luke Abraham, Martin B. Andrews, Nicolas Bellouin, Jo Browse, Ken S. Carslaw, Mohit Dalvi, Gerd A. Folberth, Matthew Glover, Daniel P. Grosvenor, Catherine Hardacre, Richard Hill, Ben Johnson, Andy Jones, Zak Kipling, Graham Mann, James Mollard, Fiona M. O'Connor, Julien Palmiéri, Carly Reddington, Steven T. Rumbold, Mark Richardson, Nick A. J. Schutgens, Philip Stier, Marc Stringer, Yongming Tang, Jeremy Walton, Stephanie Woodward, and Andrew Yool
Geosci. Model Dev., 13, 6383–6423, https://doi.org/10.5194/gmd-13-6383-2020, https://doi.org/10.5194/gmd-13-6383-2020, 2020
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Aerosols are an important component of the Earth system. Here, we comprehensively document and evaluate the aerosol schemes as implemented in the physical and Earth system models, HadGEM3-GC3.1 and UKESM1. This study provides a useful characterisation of the aerosol climatology in both models, facilitating the understanding of the numerous aerosol–climate interaction studies that will be conducted for CMIP6 and beyond.
Twan van Noije, Tommi Bergman, Philippe Le Sager, Declan O'Donnell, Risto Makkonen, María Gonçalves-Ageitos, Ralf Döscher, Uwe Fladrich, Jost von Hardenberg, Jukka-Pekka Keskinen, Hannele Korhonen, Anton Laakso, Stelios Myriokefalitakis, Pirkka Ollinaho, Carlos Pérez García-Pando, Thomas Reerink, Roland Schrödner, Klaus Wyser, and Shuting Yang
Geosci. Model Dev. Discuss., https://doi.org/10.5194/gmd-2020-413, https://doi.org/10.5194/gmd-2020-413, 2020
Preprint under review for GMD
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This paper documents the global climate model EC-Earth3-AerChem, one of the members of the EC-Earth3 family of models participating in the Coupled Model Intercomparison Project phase 6 (CMIP6). We describe the model in detail and provide information about the applied tuning and spin-up procedures. The model's performance is characterized using coupled simulations conducted for CMIP6. The model has an effective equilibrium climate sensitivity of 3.9 °C and a transient climate response of 2.1 °C.
Daniel P. Grosvenor and Kenneth S. Carslaw
Atmos. Chem. Phys., 20, 15681–15724, https://doi.org/10.5194/acp-20-15681-2020, https://doi.org/10.5194/acp-20-15681-2020, 2020
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Particles arising from human activity interact with clouds and affect how much of the Sun's energy is reflected away. Lack of understanding about how to represent this in models leads to large uncertainties in climate predictions. We quantify cloud responses to particles in the latest UK Met Office climate model over the North Atlantic Ocean, showing that, in contrast to suggestions elsewhere, increases in cloud coverage and thickness are important over large areas.
Xiaoxia Shang, Elina Giannakaki, Stephanie Bohlmann, Maria Filioglou, Annika Saarto, Antti Ruuskanen, Ari Leskinen, Sami Romakkaniemi, and Mika Komppula
Atmos. Chem. Phys., 20, 15323–15339, https://doi.org/10.5194/acp-20-15323-2020, https://doi.org/10.5194/acp-20-15323-2020, 2020
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Measurements of the multi-wavelength Raman polarization lidar PollyXT have been combined with measurements of pollen type and concentration using a traditional pollen sampler at a rural forest site in Kuopio, Finland. The depolarization ratio was enhanced when there were pollen grains in the atmosphere, illustrating the potential of lidar to track pollen grains in the atmosphere. The depolarization ratio of pure pollen particles was assessed for birch and pine pollen using a novel algorithm.
Joonas Merikanto, Kalle Nordling, Petri Räisänen, Jouni Räisänen, Declan O'Donnell, Antti-Ilari Partanen, and Hannele Korhonen
Atmos. Chem. Phys. Discuss., https://doi.org/10.5194/acp-2020-1029, https://doi.org/10.5194/acp-2020-1029, 2020
Preprint under review for ACP
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Human-induced aerosols concentrate around their emission sources, yet their climate effects span far and wide. Here, we use two climate models to robustly explore the mechanisms how Asian aerosols impact temperatures across the globe. A total removal of Asian aerosols increases the global temperatures by 0.26 ± 0.04 °C in the models, with most of the uncertainty arising from modelled cloud responses.
Johannes Quaas, Antti Arola, Brian Cairns, Matthew Christensen, Hartwig Deneke, Annica M. L. Ekman, Graham Feingold, Ann Fridlind, Edward Gryspeerdt, Otto Hasekamp, Zhanqing Li, Antti Lipponen, Po-Lun Ma, Johannes Mülmenstädt, Athanasios Nenes, Joyce E. Penner, Daniel Rosenfeld, Roland Schrödner, Kenneth Sinclair, Odran Sourdeval, Philip Stier, Matthias Tesche, Bastiaan van Diedenhoven, and Manfred Wendisch
Atmos. Chem. Phys., 20, 15079–15099, https://doi.org/10.5194/acp-20-15079-2020, https://doi.org/10.5194/acp-20-15079-2020, 2020
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Anthropogenic pollution particles – aerosols – serve as cloud condensation nuclei and thus increase cloud droplet concentration and the clouds' reflection of sunlight (a cooling effect on climate). This Twomey effect is poorly constrained by models and requires satellite data for better quantification. The review summarizes the challenges in properly doing so and outlines avenues for progress towards a better use of aerosol retrievals and better retrievals of droplet concentrations.
Paraskevi Georgakaki, Aikaterini Bougiatioti, Jörg Wieder, Claudia Mignani, Fabiola Ramelli, Zamin A. Kanji, Jan Henneberger, Maxime Hervo, Alexis Berne, Ulrike Lohmann, and Athanasios Nenes
Atmos. Chem. Phys. Discuss., https://doi.org/10.5194/acp-2020-1036, https://doi.org/10.5194/acp-2020-1036, 2020
Preprint under review for ACP
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Aerosol and cloud observations coupled with a droplet activation parameterization was used to investigate the aerosol-cloud droplet link in mixed-phase Alpine clouds. Predicted droplet number, Nd, agrees with observations, and never exceeds a characteristic
limiting droplet number, Ndlim, which depends solely on σw. Nd becomes velocity-limited when it is to within 50 % of Ndlim. Identifying when dynamical changes control Nd variability is central for understanding aerosol-cloud interactions.
Ramiro Checa-Garcia, Yves Balkanski, Samuel Albani, Tommi Bergman, Ken Carslaw, Anne Cozic, Chris Dearden, Beatrice Marticorena, Martine Michou, Twan van Noije, Pierre Nabat, Fionna O'Connor, Dirk Olivié, Joseph M. Prospero, Philippe Le Sager, Michael Schulz, and Catherine Scott
Atmos. Chem. Phys. Discuss., https://doi.org/10.5194/acp-2020-1147, https://doi.org/10.5194/acp-2020-1147, 2020
Preprint under review for ACP
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Thousands of tons of dust are emitted into the atmosphere every year producing important impacts on the Earth system. However, the current global climate models are not yet able to reproduce dust emissions, transport and depositions with the desirable accuracy. Our study analyses 5 different Earth-System-Models to report those aspects to be improved to reproduce better available observations and increase the consistency between models and therefore decrease the current uncertainties.
Ulrike Proske, Verena Bessenbacher, Zane Dedekind, Ulrike Lohmann, and David Neubauer
Atmos. Chem. Phys. Discuss., https://doi.org/10.5194/acp-2020-1145, https://doi.org/10.5194/acp-2020-1145, 2020
Revised manuscript accepted for ACP
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Ice crystals falling out of one cloud can initiate freezing in a second cloud below. We estimate the occurrence frequency of this natural cloud seeding over Switzerland from satellite data and sublimation calculations. We find that such situations with an ice cloud above another cloud are frequent and that the falling crystals survive the fall between two clouds in a significant number of cases, suggesting that natural cloud seeding is an important phenomenon over Switzerland.
Ari Laaksonen, Jussi Malila, and Athanasios Nenes
Atmos. Chem. Phys., 20, 13579–13589, https://doi.org/10.5194/acp-20-13579-2020, https://doi.org/10.5194/acp-20-13579-2020, 2020
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Aerosol particles containing black carbon are ubiquitous in the atmosphere and originate from combustion processes. We examine their capability to act as condensation centers for water vapor. We make use of published experimental data sets for different types of black carbon particles, ranging from very pure particles to particles that contain both black carbon and water soluble organic matter, and we show that a recently developed theory reproduces most of the experimental results.
Sandip S. Dhomse, Graham W. Mann, Juan Carlos Antuña Marrero, Sarah E. Shallcross, Martyn P. Chipperfield, Kenneth S. Carslaw, Lauren Marshall, N. Luke Abraham, and Colin E. Johnson
Atmos. Chem. Phys., 20, 13627–13654, https://doi.org/10.5194/acp-20-13627-2020, https://doi.org/10.5194/acp-20-13627-2020, 2020
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We confirm downward adjustment of SO2 emission to simulate the Pinatubo aerosol cloud with aerosol microphysics models. Similar adjustment is also needed to simulate the El Chichón and Agung volcanic cloud, indicating potential missing removal or vertical redistribution process in models. Important inhomogeneities in the CMIP6 forcing datasets after Agung and El Chichón eruptions are difficult to reconcile. Quasi-biennial oscillation plays an important role in modifying stratospheric warming.
Erik Johansson, Abhay Devasthale, Michael Tjernström, Annica M. L. Ekman, Klaus Wyser, and Tristan L'Ecuyer
Geosci. Model Dev. Discuss., https://doi.org/10.5194/gmd-2020-277, https://doi.org/10.5194/gmd-2020-277, 2020
Preprint under review for GMD
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Understanding the coupling of clouds to large-scale circulation is a grand challenge for the climate community. Cloud radiative heating (CRH) is a key parameter in this coupling and is therefore essential to model realistically. We, therefore, evaluate a climate model against satellite observations. Our findings indicate good agreement in the seasonal pattern of CRH even if the magnitude differs. We also find that increasing the horizontal resolution in the model has little effect on the CRH.
Ananth Ranjithkumar, Hamish Gordon, Christina Williamson, Andrew Rollins, Kirsty J. Pringle, Agnieszka Kupc, Nathan Luke Abraham, Charles A. Brock, and Kenneth S. Carslaw
Atmos. Chem. Phys. Discuss., https://doi.org/10.5194/acp-2020-1071, https://doi.org/10.5194/acp-2020-1071, 2020
Revised manuscript accepted for ACP
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The effect aerosols have on climate can be better understood by studying their vertical and spatial distribution throughout the atmosphere. We use observation data from the ATom Campaign and evaluate the vertical profile of aerosol number concentration, Sulphur dioxide and condensation sink using UKESM (UK earth system model). We identify uncertainties in key atmospheric processes that help improve their theoretical representation in global climate models.
Laura J. Wilcox, Zhen Liu, Bjørn H. Samset, Ed Hawkins, Marianne T. Lund, Kalle Nordling, Sabine Undorf, Massimo Bollasina, Annica M. L. Ekman, Srinath Krishnan, Joonas Merikanto, and Andrew G. Turner
Atmos. Chem. Phys., 20, 11955–11977, https://doi.org/10.5194/acp-20-11955-2020, https://doi.org/10.5194/acp-20-11955-2020, 2020
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Projected changes in man-made aerosol range from large reductions to moderate increases in emissions until 2050. Rapid reductions between the present and the 2050s lead to enhanced increases in global and Asian summer monsoon precipitation relative to scenarios with continued increases in aerosol. Relative magnitude and spatial distribution of aerosol changes are particularly important for South Asian summer monsoon precipitation changes, affecting the sign of the trend in the coming decades.
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.
Alejandro Baró Pérez, Abhay Devasthale, Frida Bender, and Annica M. L. Ekman
Atmos. Chem. Phys. Discuss., https://doi.org/10.5194/acp-2020-1089, https://doi.org/10.5194/acp-2020-1089, 2020
Preprint under review for ACP
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We study the impacts of biomass burning plumes on radiation and clouds over the Southeast Atlantic using data derived from satellite observations and data-constrained models simulations. A substantial fraction of the aerosols within the plumes is not classified as smoke by the satellite. The atmosphere warms more with increasing smoke aerosol loading, but we find no effect on the clouds. The cloud top radiative cooling decreases weakly with increasing moisture within the overlying aerosol layer.
Jaakko Ahola, Hannele Korhonen, Juha Tonttila, Sami Romakkaniemi, Harri Kokkola, and Tomi Raatikainen
Atmos. Chem. Phys., 20, 11639–11654, https://doi.org/10.5194/acp-20-11639-2020, https://doi.org/10.5194/acp-20-11639-2020, 2020
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In this study, we present an improved cloud model that reproduces the behaviour of mixed-phase clouds containing liquid droplets and ice crystals in more detail than before. This model is a convenient computational tool that enables the study of phenomena that cannot fit into a laboratory. These clouds have a significant role in climate, but they are not yet properly understood. Here, we show the advantages of the new model in a case study focusing on Arctic mixed-phase clouds.
Annika Lauber, Jan Henneberger, Claudia Mignani, Fabiola Ramelli, Julie T. Pasquier, Jörg Wieder, Maxime Hervo, and Ulrike Lohmann
Atmos. Chem. Phys. Discuss., https://doi.org/10.5194/acp-2020-986, https://doi.org/10.5194/acp-2020-986, 2020
Revised manuscript accepted for ACP
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An accurate prediction of the ice crystal number concentration (ICNC) is important to determine the radiation budget, lifetime, and precipitation formation of clouds. Even though secondary ice processes can increase the ICNC by several orders of magnitude, they are poorly constrained and lack a well-founded quantification. During measurements on a mountain slope, a high ICNC of small ice crystals was observed just below 0 °C, attributed to a secondary ice process and parameterized in this study.
Fabiola Ramelli, Jan Henneberger, Robert O. David, Johannes Bühl, Martin Radenz, Patric Seifert, Jörg Wieder, Annika Lauber, Julie T. Pasquier, Ronny Engelmann, Claudia Mignani, Maxime Hervo, and Ulrike Lohmann
Atmos. Chem. Phys. Discuss., https://doi.org/10.5194/acp-2020-772, https://doi.org/10.5194/acp-2020-772, 2020
Revised manuscript under review for ACP
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Orographic mixed-phase clouds are an important source of precipitation, but the ice formation processes within them remain uncertain. Here we investigate the origins of ice crystals in a mixed-phase cloud in the Swiss Alps using aerosol and cloud data from in situ and remote sensing observations. We found that ice formation primarily occurs in cloud top generating cells and low-level feeder clouds. Our results indicate that secondary ice processes occur in both of these regions.
Georgia Sotiropoulou, Luisa Ickes, Athanasios Nenes, and Annica M. L. Ekman
Atmos. Chem. Phys. Discuss., https://doi.org/10.5194/acp-2020-786, https://doi.org/10.5194/acp-2020-786, 2020
Preprint under review for ACP
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Mixed-phase clouds are a large source of uncertainty in projections of the Arctic climate. This is partly due to the poor representation of the cloud-ice formation processes. Implementing a parameterization for ice multiplication due to mechanical break-up upon collision of two ice particles in a high resolution model improves cloud-ice phase representation. However, the results are sensitive to poorly constrained microphysical parameters (e.g. ice habit, rimed fraction, autoconversion rate).
Konstantinos-Matthaios Doulgeris, Mika Komppula, Sami Romakkaniemi, Antti-Pekka Hyvärinen, Veli-Matti Kerminen, and David Brus
Atmos. Meas. Tech., 13, 5129–5147, https://doi.org/10.5194/amt-13-5129-2020, https://doi.org/10.5194/amt-13-5129-2020, 2020
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We intercompared three cloud spectrometers ground setups in conditions with frequently occurring supercooled clouds. The measurements were conducted during the Pallas Cloud Experiment (PaCE) in 2013, in the Finnish sub-Arctic region at Sammaltunturi station. The main meteorological parameters influencing the spectrometers' performance was the wind direction. Final recommendations and our view on the main limitations of each spectrometer ground setup are presented.
Luisa Ickes, Grace C. E. Porter, Robert Wagner, Michael P. Adams, Sascha Bierbauer, Allan K. Bertram, Merete Bilde, Sigurd Christiansen, Annica M. L. Ekman, Elena Gorokhova, Kristina Höhler, Alexei A. Kiselev, Caroline Leck, Ottmar Möhler, Benjamin J. Murray, Thea Schiebel, Romy Ullrich, and Matthew E. Salter
Atmos. Chem. Phys., 20, 11089–11117, https://doi.org/10.5194/acp-20-11089-2020, https://doi.org/10.5194/acp-20-11089-2020, 2020
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The Arctic is a region where aerosols are scarce. Sea spray might be a potential source of aerosols acting as ice-nucleating particles. We investigate two common phytoplankton species (Melosira arctica and Skeletonema marinoi) and present their ice nucleation activity in comparison with Arctic seawater microlayer samples from different field campaigns. We also aim to understand the aerosolization process of marine biological samples and the potential effect on the ice nucleation activity.
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.
Innocent Kudzotsa, Harri Kokkola, Juha Tonttila, Tomi Raatikainen, and Sami Romakkaniemi
Atmos. Chem. Phys. Discuss., https://doi.org/10.5194/acp-2020-851, https://doi.org/10.5194/acp-2020-851, 2020
Revised manuscript has not been submitted
Craig Poku, Andrew N. Ross, Adrian A. Hill, Alan M. Blyth, and Ben Shipway
Atmos. Chem. Phys. Discuss., https://doi.org/10.5194/acp-2020-904, https://doi.org/10.5194/acp-2020-904, 2020
Preprint under review for ACP
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We present a new aerosol activation scheme that is suitable for modelling both fog and convective clouds. Most current activation schemes are designed for convective cloud and we demonstrate that using them to model fog can negatively impact its lifecycle. Our scheme has been used to model an observed fog case in the UK, where we demonstrate that a more physically based representation of aerosol activation is required to capture the transition to a deeper layer; more inline with observations.
Fabiola Ramelli, Jan Henneberger, Robert Oscar David, Annika Lauber, Julie Thérèse Pasquier, Jörg Wieder, Johannes Bühl, Patric Seifert, Ronny Engelmann, Maxime Hervo, and Ulrike Lohmann
Atmos. Chem. Phys. Discuss., https://doi.org/10.5194/acp-2020-774, https://doi.org/10.5194/acp-2020-774, 2020
Revised manuscript accepted for ACP
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Interactions between dynamics, microphysics and orography can enhance precipitation. Yet the exact role of these interactions is still uncertain. Here we investigate the role of low-level blocking and turbulence for hydrometeor growth by combining remote sensing and in situ observations. The observations show that blocked flow can induce the formation of liquid layers and that turbulence can enhance ice growth, demonstrating the importance of local flow effects for orographic precipitation.
Leighton A. Regayre, Julia Schmale, Jill S. Johnson, Christian Tatzelt, Andrea Baccarini, Silvia Henning, Masaru Yoshioka, Frank Stratmann, Martin Gysel-Beer, Daniel P. Grosvenor, and Ken S. Carslaw
Atmos. Chem. Phys., 20, 10063–10072, https://doi.org/10.5194/acp-20-10063-2020, https://doi.org/10.5194/acp-20-10063-2020, 2020
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The amount of energy reflected back into space because of man-made particles is highly uncertain. Processes related to naturally occurring particles cause most of the uncertainty, but these processes are poorly constrained by present-day measurements. We show that measurements over the Southern Ocean, far from pollution sources, efficiently reduce climate model uncertainties. Our results pave the way to designing experiments and measurement campaigns that reduce this uncertainty even further.
Robert J. Allen, Steven Turnock, Pierre Nabat, David Neubauer, Ulrike Lohmann, Dirk Olivié, Naga Oshima, Martine Michou, Tongwen Wu, Jie Zhang, Toshihiko Takemura, Michael Schulz, Kostas Tsigaridis, Susanne E. Bauer, Louisa Emmons, Larry Horowitz, Vaishali Naik, Twan van Noije, Tommi Bergman, Jean-Francois Lamarque, Prodromos Zanis, Ina Tegen, Daniel M. Westervelt, Philippe Le Sager, Peter Good, Sungbo Shim, Fiona O'Connor, Dimitris Akritidis, Aristeidis K. Georgoulias, Makoto Deushi, Lori T. Sentman, Jasmin G. John, Shinichiro Fujimori, and William J. Collins
Atmos. Chem. Phys., 20, 9641–9663, https://doi.org/10.5194/acp-20-9641-2020, https://doi.org/10.5194/acp-20-9641-2020, 2020
Jill S. Johnson, Leighton A. Regayre, Masaru Yoshioka, Kirsty J. Pringle, Steven T. Turnock, Jo Browse, David M. H. Sexton, John W. Rostron, Nick A. J. Schutgens, Daniel G. Partridge, Dantong Liu, James D. Allan, Hugh Coe, Aijun Ding, David D. Cohen, Armand Atanacio, Ville Vakkari, Eija Asmi, and Ken S. Carslaw
Atmos. Chem. Phys., 20, 9491–9524, https://doi.org/10.5194/acp-20-9491-2020, https://doi.org/10.5194/acp-20-9491-2020, 2020
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We use over 9000 monthly aggregated grid-box measurements of aerosol to constrain the uncertainty in the HadGEM3-UKCA climate model. Measurements of AOD, PM2.5, particle number concentrations, sulfate and organic mass concentrations are compared to 1 million
variantsof the model using an implausibility metric. Despite many compensating effects in the model, the procedure constrains the probability distributions of many parameters, and direct radiative forcing uncertainty is reduced by 34 %.
Ines Bulatovic, Adele L. Igel, Caroline Leck, Jost Heintzenberg, Ilona Riipinen, and Annica M. L. Ekman
Atmos. Chem. Phys. Discuss., https://doi.org/10.5194/acp-2020-665, https://doi.org/10.5194/acp-2020-665, 2020
Revised manuscript accepted for ACP
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We use detailed numerical modelling to show that small aerosol particles (diameters ~ 25–80 nm, so-called Aitken mode particles) significantly influence low-level cloud properties in the clean summertime high Arctic. The small particles can help sustain clouds when the concentration of larger particles is low (< 10–20 cm−3). Measurements from four different observational campaigns in the high Arctic support the modelling results as they indicate that Aitken mode aerosols are frequently activated.
Maria Filioglou, Elina Giannakaki, John Backman, Jutta Kesti, Anne Hirsikko, Ronny Engelmann, Ewan O'Connor, Jari T. T. Leskinen, Xiaoxia Shang, Hannele Korhonen, Heikki Lihavainen, Sami Romakkaniemi, and Mika Komppula
Atmos. Chem. Phys., 20, 8909–8922, https://doi.org/10.5194/acp-20-8909-2020, https://doi.org/10.5194/acp-20-8909-2020, 2020
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Dust optical properties are region-dependent. Saharan, Asian, and Arabian dusts do not pose similar optical properties in terms of lidar ratios; thus, a universal lidar ratio for dust particles will lead to biases. The present study analyses observations over the United Arab Emirates, quantifying the optical and geometrical extents of the aerosol layers in the area, providing at the same time the Arabian dust properties along with chemical analysis of dust samples collected in the region.
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.
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. Discuss., https://doi.org/10.5194/acp-2020-571, https://doi.org/10.5194/acp-2020-571, 2020
Revised manuscript accepted for ACP
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The impact of aerosols on clouds, including mixed-phase clouds, is a large source of uncertainty for future climate projections. Our results show that the reflectivity of a convective cloud field is sensitive to the presence and efficiency of ice-nucleating particles in the Saharan outflow region. Differences in aerosol source or composition, for the same aerosol size distribution, can cause differences in the outgoing radiation from regions dominated by tropical convection.
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.
Dominik Stolzenburg, Mario Simon, Ananth Ranjithkumar, Andreas Kürten, Katrianne Lehtipalo, Hamish Gordon, Sebastian Ehrhart, Henning Finkenzeller, Lukas Pichelstorfer, Tuomo Nieminen, Xu-Cheng He, Sophia Brilke, Mao Xiao, António Amorim, Rima Baalbaki, Andrea Baccarini, Lisa Beck, Steffen Bräkling, Lucía Caudillo Murillo, Dexian Chen, Biwu Chu, Lubna Dada, António Dias, Josef Dommen, Jonathan Duplissy, Imad El Haddad, Lukas Fischer, Loic Gonzalez Carracedo, Martin Heinritzi, Changhyuk Kim, Theodore K. Koenig, Weimeng Kong, Houssni Lamkaddam, Chuan Ping Lee, Markus Leiminger, Zijun Li, Vladimir Makhmutov, Hanna E. Manninen, Guillaume Marie, Ruby Marten, Tatjana Müller, Wei Nie, Eva Partoll, Tuukka Petäjä, Joschka Pfeifer, Maxim Philippov, Matti P. Rissanen, Birte Rörup, Siegfried Schobesberger, Simone Schuchmann, Jiali Shen, Mikko Sipilä, Gerhard Steiner, Yuri Stozhkov, Christian Tauber, Yee Jun Tham, António Tomé, Miguel Vazquez-Pufleau, Andrea C. Wagner, Mingyi Wang, Yonghong Wang, Stefan K. Weber, Daniela Wimmer, Peter J. Wlasits, Yusheng Wu, Qing Ye, Marcel Zauner-Wieczorek, Urs Baltensperger, Kenneth S. Carslaw, Joachim Curtius, Neil M. Donahue, Richard C. Flagan, Armin Hansel, Markku Kulmala, Jos Lelieveld, Rainer Volkamer, Jasper Kirkby, and Paul M. Winkler
Atmos. Chem. Phys., 20, 7359–7372, https://doi.org/10.5194/acp-20-7359-2020, https://doi.org/10.5194/acp-20-7359-2020, 2020
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Sulfuric acid is a major atmospheric vapour for aerosol formation. If new particles grow fast enough, they can act as cloud droplet seeds or affect air quality. In a controlled laboratory set-up, we demonstrate that van der Waals forces enhance growth from sulfuric acid. We disentangle the effects of ammonia, ions and particle hydration, presenting a complete picture of sulfuric acid growth from molecular clusters onwards. In a climate model, we show its influence on the global aerosol budget.
Annette K. Miltenberger and Paul R. Field
Atmos. Chem. Phys. Discuss., https://doi.org/10.5194/acp-2020-253, https://doi.org/10.5194/acp-2020-253, 2020
Revised manuscript accepted for ACP
Montserrat Costa-Surós, Odran Sourdeval, Claudia Acquistapace, Holger Baars, Cintia Carbajal Henken, Christa Genz, Jonas Hesemann, Cristofer Jimenez, Marcel König, Jan Kretzschmar, Nils Madenach, Catrin I. Meyer, Roland Schrödner, Patric Seifert, Fabian Senf, Matthias Brueck, Guido Cioni, Jan Frederik Engels, Kerstin Fieg, Ksenia Gorges, Rieke Heinze, Pavan Kumar Siligam, Ulrike Burkhardt, Susanne Crewell, Corinna Hoose, Axel Seifert, Ina Tegen, and Johannes Quaas
Atmos. Chem. Phys., 20, 5657–5678, https://doi.org/10.5194/acp-20-5657-2020, https://doi.org/10.5194/acp-20-5657-2020, 2020
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The impact of anthropogenic aerosols on clouds is a key uncertainty in climate change. This study analyses large-domain simulations with a new high-resolution model to investigate the differences in clouds between 1985 and 2013 comparing multiple observational datasets. The differences in aerosol and in cloud droplet concentrations are clearly detectable. For other quantities, the detection and attribution proved difficult, despite a substantial impact on the Earth's energy budget.
Thomas Kühn, Kaarle Kupiainen, Tuuli Miinalainen, Harri Kokkola, Ville-Veikko Paunu, Anton Laakso, Juha Tonttila, Rita Van Dingenen, Kati Kulovesi, Niko Karvosenoja, and Kari E. J. Lehtinen
Atmos. Chem. Phys., 20, 5527–5546, https://doi.org/10.5194/acp-20-5527-2020, https://doi.org/10.5194/acp-20-5527-2020, 2020
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We investigate the effects of black carbon (BC) mitigation on Arctic climate and human health, accounting for the concurrent reduction of other aerosol species. While BC is attributed a net warming effect on climate, most other aerosol species cool the planet. We find that the direct radiative effect of mitigating BC induces cooling, while aerosol–cloud effects offset this cooling and introduce large uncertainties. Furthermore, the reduced aerosol emissions reduce human mortality considerably.
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.
Mike Bush, Tom Allen, Caroline Bain, Ian Boutle, John Edwards, Anke Finnenkoetter, Charmaine Franklin, Kirsty Hanley, Humphrey Lean, Adrian Lock, James Manners, Marion Mittermaier, Cyril Morcrette, Rachel North, Jon Petch, Chris Short, Simon Vosper, David Walters, Stuart Webster, Mark Weeks, Jonathan Wilkinson, Nigel Wood, and Mohamed Zerroukat
Geosci. Model Dev., 13, 1999–2029, https://doi.org/10.5194/gmd-13-1999-2020, https://doi.org/10.5194/gmd-13-1999-2020, 2020
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In this paper we define the first Regional Atmosphere and Land (RAL) science configuration for kilometre-scale modelling using the Unified Model (UM) as the basis for the atmosphere and the Joint UK Land Environment Simulator (JULES) for the land. RAL1 defines the science configuration of the dynamics and physics schemes of the atmosphere and land. This configuration will provide a model baseline for any future weather or climate model developments to be described against.
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.
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.
Mattia Righi, Johannes Hendricks, Ulrike Lohmann, Christof Gerhard Beer, Valerian Hahn, Bernd Heinold, Romy Heller, Martina Krämer, Michael Ponater, Christian Rolf, Ina Tegen, and Christiane Voigt
Geosci. Model Dev., 13, 1635–1661, https://doi.org/10.5194/gmd-13-1635-2020, https://doi.org/10.5194/gmd-13-1635-2020, 2020
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A new cloud microphysical scheme is implemented in the global EMAC-MADE3 aerosol model and evaluated. The new scheme features a detailed parameterization for aerosol-driven ice formation in cirrus clouds, accounting for the competition between homogeneous and heterogeneous ice formation processes. The comparison against satellite data and in situ measurements shows that the model performance is in line with similar global coupled models featuring ice cloud parameterizations.
Anna Possner, Ryan Eastman, Frida Bender, and Franziska Glassmeier
Atmos. Chem. Phys., 20, 3609–3621, https://doi.org/10.5194/acp-20-3609-2020, https://doi.org/10.5194/acp-20-3609-2020, 2020
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Cloud water content and the number of droplets inside clouds covary with boundary layer depth. This covariation may amplify the change in water content due to a change in droplet number inferred from long-term observations. Taking this into account shows that the change in water content for increased droplet number in observations and high-resolution simulations agrees in shallow boundary layers. Meanwhile, deep boundary layers are under-sampled in process-scale simulations and observations.
Maria Sand, Terje K. Berntsen, Annica M. L. Ekman, Hans-Christen Hansson, and Anna Lewinschal
Atmos. Chem. Phys., 20, 3079–3089, https://doi.org/10.5194/acp-20-3079-2020, https://doi.org/10.5194/acp-20-3079-2020, 2020
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There has been a growing interest in reducing emissions of soot particles to slow global warming and improve air quality. However, estimating the effect of reduced emissions is complex, as soot particles absorb solar radiation and influence heating rates, clouds, and humidity and can influence climate far outside their emission region. Here we investigate the impact of soot emitted in four major emissions areas, using different emissions rates, to see whether location and magnitude matter.
Fabiola Ramelli, Alexander Beck, Jan Henneberger, and Ulrike Lohmann
Atmos. Meas. Tech., 13, 925–939, https://doi.org/10.5194/amt-13-925-2020, https://doi.org/10.5194/amt-13-925-2020, 2020
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Boundary layer clouds are influenced by many physical and dynamical processes, making accurate forecasting difficult. Here we present a new measurement platform on a tethered balloon to measure cloud microphysical and meteorological profiles. The unique combination of holography and balloon-borne observations allows high-resolution measurements in a well-defined volume. Field measurements in stratus clouds over the Swiss Plateau revealed unique microphysical signatures in the cloud structure.
Constanze Wellmann, Andrew I. Barrett, Jill S. Johnson, Michael Kunz, Bernhard Vogel, Ken S. Carslaw, and Corinna Hoose
Atmos. Chem. Phys., 20, 2201–2219, https://doi.org/10.5194/acp-20-2201-2020, https://doi.org/10.5194/acp-20-2201-2020, 2020
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Severe hailstorms may cause damage to buildings and crops. Thus, the forecast of numerical weather prediction (NWP) models should be as reliable as possible.
Using statistical emulation, we identify those model input parameters describing environmental conditions and cloud microphysics which lead to large uncertainties in the prediction of deep convection. We find that the impact of the input parameters on the uncertainty depends on the considered output variable.
Giulia Saponaro, Moa K. Sporre, David Neubauer, Harri Kokkola, Pekka Kolmonen, Larisa Sogacheva, Antti Arola, Gerrit de Leeuw, Inger H. H. Karset, Ari Laaksonen, and Ulrike Lohmann
Atmos. Chem. Phys., 20, 1607–1626, https://doi.org/10.5194/acp-20-1607-2020, https://doi.org/10.5194/acp-20-1607-2020, 2020
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The understanding of cloud processes is based on the quality of the representation of cloud properties. We compared cloud parameters from three models with satellite observations. We report on the performance of each data source, highlighting strengths and deficiencies, which should be considered when deriving the effect of aerosols on cloud properties.
Ross J. Herbert, Nicolas Bellouin, Ellie J. Highwood, and Adrian A. Hill
Atmos. Chem. Phys., 20, 1317–1340, https://doi.org/10.5194/acp-20-1317-2020, https://doi.org/10.5194/acp-20-1317-2020, 2020
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Marine stratocumulus clouds cover large regions of the ocean and act to cool the climate. We use high-resolution simulations to understand how observed layers of elevated smoke impact stratocumulus via the solar heating that occurs within the smoke layer. We find that the cloud response is strongest for thin, dense layers of smoke close to the cloud. The response rapidly weakens as the cloud-to-smoke gap increases. Generally, the smoke acts to thicken clouds and enhance their cooling effect.
Georgia Sotiropoulou, Sylvia Sullivan, Julien Savre, Gary Lloyd, Thomas Lachlan-Cope, Annica M. L. Ekman, and Athanasios Nenes
Atmos. Chem. Phys., 20, 1301–1316, https://doi.org/10.5194/acp-20-1301-2020, https://doi.org/10.5194/acp-20-1301-2020, 2020
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Arctic clouds constitute a large source of uncertainty in predictions of future climate. Observations indicate that the number concentration of cloud ice crystals exceeds the concentration of aerosols that can act as ice-nucleating particles (INPs). We show that ice multiplication due to mechanical break-up upon collisions between the few primary ice crystals (formed from INPs) can explain the discrepancy. Including a description of the process in climate models can improve cloud representation.
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.
Franz Friebel, Prem Lobo, David Neubauer, Ulrike Lohmann, Saskia Drossaart van Dusseldorp, Evelyn Mühlhofer, and Amewu A. Mensah
Atmos. Chem. Phys., 19, 15545–15567, https://doi.org/10.5194/acp-19-15545-2019, https://doi.org/10.5194/acp-19-15545-2019, 2019
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We investigated the change in cloud droplet activity of size-selected soot particles after being exposed to atmospheric levels of ozone over the course of 12 h. For this, we operated a 3 m3 aerosol chamber in continuous-flow mode. The results were fed into a climate model (ECHAM-HAM). We found that the oxidation of soot particles with ozone is a significant source of cloud condensation nuclei in the atmosphere.
Stephanie Bohlmann, Xiaoxia Shang, Elina Giannakaki, Maria Filioglou, Annika Saarto, Sami Romakkaniemi, and Mika Komppula
Atmos. Chem. Phys., 19, 14559–14569, https://doi.org/10.5194/acp-19-14559-2019, https://doi.org/10.5194/acp-19-14559-2019, 2019
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Measurements of the multiwavelength Raman polarization lidar PollyXT have been combined with measurements of pollen type and concentration using a traditional pollen sampler at the rural forest site in Vehmasmäki, Finland. High particle depolarization ratios were observed during an intense pollination event of birch pollen occasionally mixed with spruce pollen. Our observations illustrate the potential of the particle depolarization ratio to track pollen grains in the atmosphere.
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.
Anina Gilgen, Stiig Wilkenskjeld, Jed O. Kaplan, Thomas Kühn, and Ulrike Lohmann
Clim. Past, 15, 1885–1911, https://doi.org/10.5194/cp-15-1885-2019, https://doi.org/10.5194/cp-15-1885-2019, 2019
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Using the global aerosol–climate model ECHAM-HAM-SALSA, the effect of humans on European climate in the Roman Empire was quantified. Both land use and novel estimates of anthropogenic aerosol emissions were considered. We conducted simulations with fixed sea-surface temperatures to gain a first impression about the anthropogenic impact. While land use effects induced a regional warming for one of the reconstructions, aerosol emissions led to a cooling associated with aerosol–cloud interactions.
Linda Schneider, Christian Barthlott, Corinna Hoose, and Andrew I. Barrett
Atmos. Chem. Phys., 19, 12343–12359, https://doi.org/10.5194/acp-19-12343-2019, https://doi.org/10.5194/acp-19-12343-2019, 2019
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This study addresses the relative impact of orography, soil moisture, and aerosols on precipitation over Germany in different weather regimes. We find that the impact of these perturbations is higher for weak than for strong large-scale forcing. Furthermore, aerosols and soil moisture are both of similar importance for precipitation forecasting, which indicates that their inclusion in operational ensemble forecasting should be assessed in the future.
Duncan Watson-Parris, Nick Schutgens, Carly Reddington, Kirsty J. Pringle, Dantong Liu, James D. Allan, Hugh Coe, Ken S. Carslaw, and Philip Stier
Atmos. Chem. Phys., 19, 11765–11790, https://doi.org/10.5194/acp-19-11765-2019, https://doi.org/10.5194/acp-19-11765-2019, 2019
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The vertical distribution of aerosol in the atmosphere affects its ability to act as cloud condensation nuclei and changes the amount of sunlight it absorbs or reflects. Common global measurements of aerosol provide no information about this vertical distribution. Using a global collection of in situ aircraft measurements to compare with an aerosol–climate model (ECHAM-HAM), we explore the key processes controlling this distribution and find that wet removal plays a key role.
André Welti, Ulrike Lohmann, and Zamin A. Kanji
Atmos. Chem. Phys., 19, 10901–10918, https://doi.org/10.5194/acp-19-10901-2019, https://doi.org/10.5194/acp-19-10901-2019, 2019
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The ice nucleation ability of singly immersed feldspar particles in suspended water droplets relevant for ice crystal formation under mixed-phase cloud conditions is presented. The effects of particle size, crystal structure, trace metal and mineralogical composition are discussed by testing up to five different diameters in the submicron range and nine different feldspar samples at conditions relevant for ice nucleation in mixed-phase clouds.
David Neubauer, Sylvaine Ferrachat, Colombe Siegenthaler-Le Drian, Philip Stier, Daniel G. Partridge, Ina Tegen, Isabelle Bey, Tanja Stanelle, Harri Kokkola, and Ulrike Lohmann
Geosci. Model Dev., 12, 3609–3639, https://doi.org/10.5194/gmd-12-3609-2019, https://doi.org/10.5194/gmd-12-3609-2019, 2019
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The global aerosol–climate model ECHAM6.3–HAM2.3 as well as the previous model versions ECHAM5.5–HAM2.0 and ECHAM6.1–HAM2.2 are evaluated. The simulation of clouds has improved in ECHAM6.3–HAM2.3. This has an impact on effective radiative forcing due to aerosol–radiation and aerosol–cloud interactions and equilibrium climate sensitivity, which are weaker in ECHAM6.3–HAM2.3 than in the previous model versions.
Franziska Glassmeier, Fabian Hoffmann, Jill S. Johnson, Takanobu Yamaguchi, Ken S. Carslaw, and Graham Feingold
Atmos. Chem. Phys., 19, 10191–10203, https://doi.org/10.5194/acp-19-10191-2019, https://doi.org/10.5194/acp-19-10191-2019, 2019
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The climatic relevance of aerosol–cloud interactions depends on the sensitivity of the radiative effect of clouds to certain cloud properties. We derive the dependence of cloud fraction, cloud albedo, and the relative cloud radiative effect on the number of cloud droplets and on liquid water path from a large set of detailed simulations of stratocumulus clouds.
Kalle Nordling, Hannele Korhonen, Petri Räisänen, Muzaffer Ege Alper, Petteri Uotila, Declan O'Donnell, and Joonas Merikanto
Atmos. Chem. Phys., 19, 9969–9987, https://doi.org/10.5194/acp-19-9969-2019, https://doi.org/10.5194/acp-19-9969-2019, 2019
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We carry out long equilibrium climate simulations with two modern climate models and show that the climate model dynamic response contributes strongly to the anthropogenic aerosol response. We demonstrate that identical aerosol descriptions do not improve climate model skill to estimate regional anthropogenic aerosol impacts. Our experiment utilized two independent climate models (NorESM and ECHAM6) with an identical description for aerosols optical properties and indirect effect.
Erika Toivonen, Marjo Hippi, Hannele Korhonen, Ari Laaksonen, Markku Kangas, and Joni-Pekka Pietikäinen
Geosci. Model Dev., 12, 3481–3501, https://doi.org/10.5194/gmd-12-3481-2019, https://doi.org/10.5194/gmd-12-3481-2019, 2019
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We evaluated the skill of the road weather model RoadSurf to reproduce present-day road weather conditions in Finland when driven by a high-resolution regional climate model. Simulated road surface temperatures and conditions were compared to observations between 2002 and 2014 at 25 Finnish road weather stations. RoadSurf accurately captured the main characteristics of road weather conditions. Thus, this model can be used to study the future scenarios of road weather in the study area.
Gesa K. Eirund, Anna Possner, and Ulrike Lohmann
Atmos. Chem. Phys., 19, 9847–9864, https://doi.org/10.5194/acp-19-9847-2019, https://doi.org/10.5194/acp-19-9847-2019, 2019
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Low-level mixed-phase cloud (MPC) properties can be highly affected by the ambient aerosol concentration, especially in pristine environments like the Arctic. By employing high-resolution model simulations we investigate the response of a MPC over an open ocean and a sea ice surface to aerosol perturbations. While we find a strong initial sensitivity to changes in aerosol concentration in both cloud regimes, the magnitude as well as the long-term cloud response depends on the surface condition.
Remo Dietlicher, David Neubauer, and Ulrike Lohmann
Atmos. Chem. Phys., 19, 9061–9080, https://doi.org/10.5194/acp-19-9061-2019, https://doi.org/10.5194/acp-19-9061-2019, 2019
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Ice crystals in clouds cover a spectrum of shapes and sizes. We show the first results of a consistent representation of the cloud ice spectrum in the climate model ECHAM6-HAM2. The simulated cloud fields are linked to their sources by new diagnostics. We find that only a small fraction of ice clouds is initiated by freezing of cloud droplets in the mixed-phase temperature regime while most ice forms at temperatures colder than −35 °C.
Laura J. Wilcox, Nick Dunstone, Anna Lewinschal, Massimo Bollasina, Annica M. L. Ekman, and Eleanor J. Highwood
Atmos. Chem. Phys., 19, 9081–9095, https://doi.org/10.5194/acp-19-9081-2019, https://doi.org/10.5194/acp-19-9081-2019, 2019
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Asian anthropogenic aerosol emissions have increased rapidly since 1980. In winter, this has resulted in warming over China and cooling over India. Using models of different levels of complexity, we show that Asian-aerosol-induced heating anomalies in the western and northern North Pacific establish a circulation pattern that causes cooling in North America and Europe. This connection makes these regions potentially sensitive to any reductions of Asian aerosol emissions in the near future.
George S. Fanourgakis, Maria Kanakidou, Athanasios Nenes, Susanne E. Bauer, Tommi Bergman, Ken S. Carslaw, Alf Grini, Douglas S. Hamilton, Jill S. Johnson, Vlassis A. Karydis, Alf Kirkevåg, John K. Kodros, Ulrike Lohmann, Gan Luo, Risto Makkonen, Hitoshi Matsui, David Neubauer, Jeffrey R. Pierce, Julia Schmale, Philip Stier, Kostas Tsigaridis, Twan van Noije, Hailong Wang, Duncan Watson-Parris, Daniel M. Westervelt, Yang Yang, Masaru Yoshioka, Nikos Daskalakis, Stefano Decesari, Martin Gysel-Beer, Nikos Kalivitis, Xiaohong Liu, Natalie M. Mahowald, Stelios Myriokefalitakis, Roland Schrödner, Maria Sfakianaki, Alexandra P. Tsimpidi, Mingxuan Wu, and Fangqun Yu
Atmos. Chem. Phys., 19, 8591–8617, https://doi.org/10.5194/acp-19-8591-2019, https://doi.org/10.5194/acp-19-8591-2019, 2019
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Effects of aerosols on clouds are important for climate studies but are among the largest uncertainties in climate projections. This study evaluates the skill of global models to simulate aerosol, cloud condensation nuclei (CCN) and cloud droplet number concentrations (CDNCs). Model results show reduced spread in CDNC compared to CCN due to the negative correlation between the sensitivities of CDNC to aerosol number concentration (air pollution) and updraft velocity (atmospheric dynamics).
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.
Stephanie Fiedler, Stefan Kinne, Wan Ting Katty Huang, Petri Räisänen, Declan O'Donnell, Nicolas Bellouin, Philip Stier, Joonas Merikanto, Twan van Noije, Risto Makkonen, and Ulrike Lohmann
Atmos. Chem. Phys., 19, 6821–6841, https://doi.org/10.5194/acp-19-6821-2019, https://doi.org/10.5194/acp-19-6821-2019, 2019
David Walters, Anthony J. Baran, Ian Boutle, Malcolm Brooks, Paul Earnshaw, John Edwards, Kalli Furtado, Peter Hill, Adrian Lock, James Manners, Cyril Morcrette, Jane Mulcahy, Claudio Sanchez, Chris Smith, Rachel Stratton, Warren Tennant, Lorenzo Tomassini, Kwinten Van Weverberg, Simon Vosper, Martin Willett, Jo Browse, Andrew Bushell, Kenneth Carslaw, Mohit Dalvi, Richard Essery, Nicola Gedney, Steven Hardiman, Ben Johnson, Colin Johnson, Andy Jones, Colin Jones, Graham Mann, Sean Milton, Heather Rumbold, Alistair Sellar, Masashi Ujiie, Michael Whitall, Keith Williams, and Mohamed Zerroukat
Geosci. Model Dev., 12, 1909–1963, https://doi.org/10.5194/gmd-12-1909-2019, https://doi.org/10.5194/gmd-12-1909-2019, 2019
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Global Atmosphere (GA) configurations of the Unified Model (UM) and Global Land (GL) configurations of JULES are developed for use in any global atmospheric modelling application. We describe a recent iteration of these configurations, GA7/GL7, which includes new aerosol and snow schemes and addresses the four critical errors identified in GA6. GA7/GL7 will underpin the UK's contributions to CMIP6, and hence their documentation is important.
Ina Tegen, David Neubauer, Sylvaine Ferrachat, Colombe Siegenthaler-Le Drian, Isabelle Bey, Nick Schutgens, Philip Stier, Duncan Watson-Parris, Tanja Stanelle, Hauke Schmidt, Sebastian Rast, Harri Kokkola, Martin Schultz, Sabine Schroeder, Nikos Daskalakis, Stefan Barthel, Bernd Heinold, and Ulrike Lohmann
Geosci. Model Dev., 12, 1643–1677, https://doi.org/10.5194/gmd-12-1643-2019, https://doi.org/10.5194/gmd-12-1643-2019, 2019
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We describe a new version of the aerosol–climate model ECHAM–HAM and show tests of the model performance by comparing different aspects of the aerosol distribution with different datasets. The updated version of HAM contains improved descriptions of aerosol processes, including updated emission fields and cloud processes. While there are regional deviations between the model and observations, the model performs well overall.
Maiken Vassel, Luisa Ickes, Marion Maturilli, and Corinna Hoose
Atmos. Chem. Phys., 19, 5111–5126, https://doi.org/10.5194/acp-19-5111-2019, https://doi.org/10.5194/acp-19-5111-2019, 2019
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Multilayer clouds are coexisting clouds at different heights. We evaluate measurements and find that Arctic multilayer clouds occur in 29 % of the investigated days at Ny-Ålesund, Svalbard. Multilayer clouds can interact by ice crystals falling from the upper cloud into the lower cloud. This is possible in 23 % of the investigated days, and in 9 % it is not possible. Weather models are still error-prone in the Arctic and we suggest that multilayer clouds should be included more in future work.
Mona Kurppa, Antti Hellsten, Pontus Roldin, Harri Kokkola, Juha Tonttila, Mikko Auvinen, Christoph Kent, Prashant Kumar, Björn Maronga, and Leena Järvi
Geosci. Model Dev., 12, 1403–1422, https://doi.org/10.5194/gmd-12-1403-2019, https://doi.org/10.5194/gmd-12-1403-2019, 2019
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This paper describes the implementation of a sectional aerosol module, SALSA, into the PALM model system 6.0. The first evaluation study shows excellent agreements with measurements. Furthermore, we show that ignoring the dry deposition of aerosol particles can overestimate aerosol number concentrations by 20 %, whereas condensation and dissolutional growth increase the total aerosol mass by over 10 % in this specific urban environment.
Anna Lewinschal, Annica M. L. Ekman, Hans-Christen Hansson, Maria Sand, Terje K. Berntsen, and Joakim Langner
Atmos. Chem. Phys., 19, 2385–2403, https://doi.org/10.5194/acp-19-2385-2019, https://doi.org/10.5194/acp-19-2385-2019, 2019
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We use a global climate model to study how anthropogenic emissions of short-lived atmospheric particles in different parts of the world influence the global temperature distribution. We find that the global mean temperature change per unit emission is similar for all emission regions, and the largest temperature response is found in the Arctic no matter where the emissions occur. However, for European emissions, the temperature change per unit emission is found to depend on emission strength.
Michael Boy, Erik S. Thomson, Juan-C. Acosta Navarro, Olafur Arnalds, Ekaterina Batchvarova, Jaana Bäck, Frank Berninger, Merete Bilde, Zoé Brasseur, Pavla Dagsson-Waldhauserova, Dimitri Castarède, Maryam Dalirian, Gerrit de Leeuw, Monika Dragosics, Ella-Maria Duplissy, Jonathan Duplissy, Annica M. L. Ekman, Keyan Fang, Jean-Charles Gallet, Marianne Glasius, Sven-Erik Gryning, Henrik Grythe, Hans-Christen Hansson, Margareta Hansson, Elisabeth Isaksson, Trond Iversen, Ingibjorg Jonsdottir, Ville Kasurinen, Alf Kirkevåg, Atte Korhola, Radovan Krejci, Jon Egill Kristjansson, Hanna K. Lappalainen, Antti Lauri, Matti Leppäranta, Heikki Lihavainen, Risto Makkonen, Andreas Massling, Outi Meinander, E. Douglas Nilsson, Haraldur Olafsson, Jan B. C. Pettersson, Nønne L. Prisle, Ilona Riipinen, Pontus Roldin, Meri Ruppel, Matthew Salter, Maria Sand, Øyvind Seland, Heikki Seppä, Henrik Skov, Joana Soares, Andreas Stohl, Johan Ström, Jonas Svensson, Erik Swietlicki, Ksenia Tabakova, Throstur Thorsteinsson, Aki Virkkula, Gesa A. Weyhenmeyer, Yusheng Wu, Paul Zieger, and Markku Kulmala
Atmos. Chem. Phys., 19, 2015–2061, https://doi.org/10.5194/acp-19-2015-2019, https://doi.org/10.5194/acp-19-2015-2019, 2019
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The Nordic Centre of Excellence CRAICC (Cryosphere–Atmosphere Interactions in a Changing Arctic Climate), funded by NordForsk in the years 2011–2016, is the largest joint Nordic research and innovation initiative to date and aimed to strengthen research and innovation regarding climate change issues in the Nordic region. The paper presents an overview of the main scientific topics investigated and provides a state-of-the-art comprehensive summary of what has been achieved in CRAICC.
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.
Yvonne Boose, Philipp Baloh, Michael Plötze, Johannes Ofner, Hinrich Grothe, Berko Sierau, Ulrike Lohmann, and Zamin A. Kanji
Atmos. Chem. Phys., 19, 1059–1076, https://doi.org/10.5194/acp-19-1059-2019, https://doi.org/10.5194/acp-19-1059-2019, 2019
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The role non-mineral components play in the freezing behavior of atmospheric desert dust is not well known. In this study, we use chemical imaging methods to investigate this for airborne and surface-collected desert dust samples. We find that in most cases the ice nucleation behavior is determined by the dust mineralogical composition. However, volatile organic material can coat active sites and decrease the dust ice nucleation ability, while biological particles can significantly increase it.
Anna Possner, Hailong Wang, Robert Wood, Ken Caldeira, and Thomas P. Ackerman
Atmos. Chem. Phys., 18, 17475–17488, https://doi.org/10.5194/acp-18-17475-2018, https://doi.org/10.5194/acp-18-17475-2018, 2018
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We quantify aerosol–cloud radiative interactions in a regime of deep open-cell stratocumuli (boundary layer depth 1.5 km), a regime which remains largely unexplored within this context and yet is more dominant than cases of shallow stratocumuli previously studied. We simulate substantial increases in albedo in a regime where ship tracks are not found and argue that such changes may escape detection and attribution through remote sensing due to the large natural variability in the system.
Michael Weger, Bernd Heinold, Christa Engler, Ulrich Schumann, Axel Seifert, Romy Fößig, Christiane Voigt, Holger Baars, Ulrich Blahak, Stephan Borrmann, Corinna Hoose, Stefan Kaufmann, Martina Krämer, Patric Seifert, Fabian Senf, Johannes Schneider, and Ina Tegen
Atmos. Chem. Phys., 18, 17545–17572, https://doi.org/10.5194/acp-18-17545-2018, https://doi.org/10.5194/acp-18-17545-2018, 2018
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The impact of desert dust on cloud formation is investigated for a major Saharan dust event over Europe by interactive regional dust modeling. Dust particles are very efficient ice-nucleating particles promoting the formation of ice crystals in clouds. The simulations show that the observed extensive cirrus development was likely related to the above-average dust load. The interactive dust–cloud feedback in the model significantly improves the agreement with aircraft and satellite observations.
Sylvia C. Sullivan, Christian Barthlott, Jonathan Crosier, Ilya Zhukov, Athanasios Nenes, and Corinna Hoose
Atmos. Chem. Phys., 18, 16461–16480, https://doi.org/10.5194/acp-18-16461-2018, https://doi.org/10.5194/acp-18-16461-2018, 2018
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Ice crystal formation in clouds can occur via thermodynamic nucleation, but also via mechanical collisions between pre-existing crystals or co-existing droplets. When descriptions of this mechanical ice generation are implemented into the COSMO weather model, we find that the contributions to crystal number from thermodynamic and mechanical processes are of the same order. Mechanical ice generation also intensifies differences in precipitation intensity between dynamic and quiescent regions.
Emma Järvinen, Olivier Jourdan, David Neubauer, Bin Yao, Chao Liu, Meinrat O. Andreae, Ulrike Lohmann, Manfred Wendisch, Greg M. McFarquhar, Thomas Leisner, and Martin Schnaiter
Atmos. Chem. Phys., 18, 15767–15781, https://doi.org/10.5194/acp-18-15767-2018, https://doi.org/10.5194/acp-18-15767-2018, 2018
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Using light diffraction it is possible to detect microscopic features within ice particles that have not yet been fully characterized. Here, this technique was applied in airborne measurements, where it was found that majority of atmospheric ice particles have features that significantly change the way ice particles interact with solar light. The microscopic features make ice-containing clouds more reflective than previously thought, which could have consequences for predicting our climate.
Meng Si, Victoria E. Irish, Ryan H. Mason, Jesús Vergara-Temprado, Sarah J. Hanna, Luis A. Ladino, Jacqueline D. Yakobi-Hancock, Corinne L. Schiller, Jeremy J. B. Wentzell, Jonathan P. D. Abbatt, Ken S. Carslaw, Benjamin J. Murray, and Allan K. Bertram
Atmos. Chem. Phys., 18, 15669–15685, https://doi.org/10.5194/acp-18-15669-2018, https://doi.org/10.5194/acp-18-15669-2018, 2018
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Using the concentrations of ice-nucleating particles (INPs) and total aerosol particles measured at three coastal marine sites, the ice-nucleating ability of aerosol particles on a per number basis and a per surface-area basis were determined as a function of size. The ice-nucleating ability was strongly dependent on size, with larger particles being more efficient. This type of information can help determine the sources of INPs and constrain the future modelling of INPs and mixed-phase clouds.
Matthias Hummel, Corinna Hoose, Bernhard Pummer, Caroline Schaupp, Janine Fröhlich-Nowoisky, and Ottmar Möhler
Atmos. Chem. Phys., 18, 15437–15450, https://doi.org/10.5194/acp-18-15437-2018, https://doi.org/10.5194/acp-18-15437-2018, 2018
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How important for clouds is the ability of biological particles to glaciate droplets at little supercooling? In a case study, the regional atmospheric model COSMO–ART is used. Perturbed and control runs are compared.
The number of ice particles that are nucleated by biological particles is highest at around −10 °C. No significant influence on the average state of the cloud ice phase was found. However, the number of ice crystals is slightly enhanced in the absence of other ice nucleators.
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.
Tuomo Nieminen, Veli-Matti Kerminen, Tuukka Petäjä, Pasi P. Aalto, Mikhail Arshinov, Eija Asmi, Urs Baltensperger, David C. S. Beddows, Johan Paul Beukes, Don Collins, Aijun Ding, Roy M. Harrison, Bas Henzing, Rakesh Hooda, Min Hu, Urmas Hõrrak, Niku Kivekäs, Kaupo Komsaare, Radovan Krejci, Adam Kristensson, Lauri Laakso, Ari Laaksonen, W. Richard Leaitch, Heikki Lihavainen, Nikolaos Mihalopoulos, Zoltán Németh, Wei Nie, Colin O'Dowd, Imre Salma, Karine Sellegri, Birgitta Svenningsson, Erik Swietlicki, Peter Tunved, Vidmantas Ulevicius, Ville Vakkari, Marko Vana, Alfred Wiedensohler, Zhijun Wu, Annele Virtanen, and Markku Kulmala
Atmos. Chem. Phys., 18, 14737–14756, https://doi.org/10.5194/acp-18-14737-2018, https://doi.org/10.5194/acp-18-14737-2018, 2018
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Atmospheric aerosols have diverse effects on air quality, human health, and global climate. One important source of aerosols is their formation via nucleation and growth in the atmosphere. We have analyzed long-term observations of regional new particle formation events around the globe and provide a comprehensive view on the characteristics of this phenomenon in diverse environments. The results are useful in developing more realistic representation of atmospheric aerosols in global models.
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.
Harri Kokkola, Thomas Kühn, Anton Laakso, Tommi Bergman, Kari E. J. Lehtinen, Tero Mielonen, Antti Arola, Scarlet Stadtler, Hannele Korhonen, Sylvaine Ferrachat, Ulrike Lohmann, David Neubauer, Ina Tegen, Colombe Siegenthaler-Le Drian, Martin G. Schultz, Isabelle Bey, Philip Stier, Nikos Daskalakis, Colette L. Heald, and Sami Romakkaniemi
Geosci. Model Dev., 11, 3833–3863, https://doi.org/10.5194/gmd-11-3833-2018, https://doi.org/10.5194/gmd-11-3833-2018, 2018
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In this paper we present a global aerosol–chemistry–climate model with the focus on its representation for atmospheric aerosol particles. In the model, aerosols are simulated using the aerosol module SALSA2.0, which in this paper is compared to satellite, ground, and aircraft-based observations of the properties of atmospheric aerosol. Based on this study, the model simulated aerosol properties compare well with the observations.
Fabian Mahrt, Claudia Marcolli, Robert O. David, Philippe Grönquist, Eszter J. Barthazy Meier, Ulrike Lohmann, and Zamin A. Kanji
Atmos. Chem. Phys., 18, 13363–13392, https://doi.org/10.5194/acp-18-13363-2018, https://doi.org/10.5194/acp-18-13363-2018, 2018
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The ice nucleation ability of different soot particles in the cirrus and mixed-phase cloud temperature regime is presented. The impact of aerosol particle size, particle morphology, organic matter and hydrophilicity on ice nucleation is examined. We propose ice nucleation proceeds via a pore condensation freezing mechanism for soot particles with the necessary physicochemical properties that nucleated ice well below water saturation.
Michael Schäfer, Katharina Loewe, André Ehrlich, Corinna Hoose, and Manfred Wendisch
Atmos. Chem. Phys., 18, 13115–13133, https://doi.org/10.5194/acp-18-13115-2018, https://doi.org/10.5194/acp-18-13115-2018, 2018
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Airborne observed horizontal fields of cloud optical thickness are compared with semi-idealized large eddy simulations of Arctic stratus. The comparison focuses on horizontal cloud inhomogeneities and directional features of the small-scale cloud structures. Using inhomogeneity parameters and autocorrelation analysis it is investigated, if the observed small-scale cloud inhomogeneities can be represented by the model. Forcings for cloud inhomogeneities are investigated in a sensitivity study.
Jill S. Johnson, Leighton A. Regayre, Masaru Yoshioka, Kirsty J. Pringle, Lindsay A. Lee, David M. H. Sexton, John W. Rostron, Ben B. B. Booth, and Kenneth S. Carslaw
Atmos. Chem. Phys., 18, 13031–13053, https://doi.org/10.5194/acp-18-13031-2018, https://doi.org/10.5194/acp-18-13031-2018, 2018
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We estimate the uncertainty in an aerosol–climate model that has been tuned to match several common types of observations. We used a large set of model simulations and built emulators so that we could generate 4 million “variants” of our climate model. Even after using nine aerosol and cloud observations to constrain the model, the uncertainty remains large. We conclude that estimates of aerosol forcing from multi-model studies are likely to be more uncertain than currently estimated.
Anina Gilgen, Carole Adolf, Sandra O. Brugger, Luisa Ickes, Margit Schwikowski, Jacqueline F. N. van Leeuwen, Willy Tinner, and Ulrike Lohmann
Atmos. Chem. Phys., 18, 11813–11829, https://doi.org/10.5194/acp-18-11813-2018, https://doi.org/10.5194/acp-18-11813-2018, 2018
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Microscopic charcoal particles are fire-specific tracers, which are presently the primary source for reconstructing past fire activity. In this study, we implement microscopic charcoal particles into a global aerosol–climate model to better understand the transport of charcoal on a large scale. We find that the model captures a significant portion of the spatial variability but fails to reproduce the extreme variability observed in the charcoal data.
Wan Ting Katty Huang, Luisa Ickes, Ina Tegen, Matteo Rinaldi, Darius Ceburnis, and Ulrike Lohmann
Atmos. Chem. Phys., 18, 11423–11445, https://doi.org/10.5194/acp-18-11423-2018, https://doi.org/10.5194/acp-18-11423-2018, 2018
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In this study, we investigated the potential impact on clouds and climate by organic particles emitted from the ocean surface, using a global climate model. These particles have previously been found to promote ice crystal formation, which may alter the properties of clouds. Our study, however, found a weak global impact by these particles, which brings into question their relative importance and points to the need for further verification with other models and at more regional scales.
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.
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
Anina Gilgen, Wan Ting Katty Huang, Luisa Ickes, David Neubauer, and Ulrike Lohmann
Atmos. Chem. Phys., 18, 10521–10555, https://doi.org/10.5194/acp-18-10521-2018, https://doi.org/10.5194/acp-18-10521-2018, 2018
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Aerosol emissions in Arctic summer and autumn are expected to increase in the future because of sea ice retreat. Using a global aerosol–climate model, we quantify the impact of increased aerosol emissions from the ocean and from Arctic shipping in the year 2050. The influence on radiation of both aerosols and clouds is analysed. Mainly driven by changes in surface albedo, the cooling effect of marine aerosols and clouds will increase. Future ship emissions might have a small net cooling effect.
Leighton A. Regayre, Jill S. Johnson, Masaru Yoshioka, Kirsty J. Pringle, David M. H. Sexton, Ben B. B. Booth, Lindsay A. Lee, Nicolas Bellouin, and Kenneth S. Carslaw
Atmos. Chem. Phys., 18, 9975–10006, https://doi.org/10.5194/acp-18-9975-2018, https://doi.org/10.5194/acp-18-9975-2018, 2018
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We sample uncertainty in one climate model by perturbing aerosol and physical atmosphere parameters. Our uncertainty is comparable to multi-model studies. Atmospheric parameters cause most of the top-of-atmosphere flux uncertainty; uncertainty in aerosol forcing is mostly caused by aerosols: both are important. The strongest aerosol forcings are inconsistent with top-of-atmosphere flux observations. Better constraint requires observations that share causes of uncertainty with aerosol forcing.
Jorma Joutsensaari, Matthew Ozon, Tuomo Nieminen, Santtu Mikkonen, Timo Lähivaara, Stefano Decesari, M. Cristina Facchini, Ari Laaksonen, and Kari E. J. Lehtinen
Atmos. Chem. Phys., 18, 9597–9615, https://doi.org/10.5194/acp-18-9597-2018, https://doi.org/10.5194/acp-18-9597-2018, 2018
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New particle formation (NPF) in the atmosphere is globally an important source of aerosol particles. NPF events are typically identified and analyzed manually by researchers from particle size distribution data day by day, which is time consuming and might be inconsistent. We have developed an automatic analysis method based on deep learning for NPF event identification. The developed method can be easily utilized to analyze any long-term datasets more accurately and consistently.
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.
Alexander Beck, Jan Henneberger, Jacob P. Fugal, Robert O. David, Larissa Lacher, and Ulrike Lohmann
Atmos. Chem. Phys., 18, 8909–8927, https://doi.org/10.5194/acp-18-8909-2018, https://doi.org/10.5194/acp-18-8909-2018, 2018
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This study assesses the impact of surface processes (e.g. blowing snow) on in situ cloud observations at Sonnblick Observatory. Vertical profiles of ice crystal number concentrations (ICNCs) above a snow-covered surface were observed up to a height of 10 m. The ICNC near the ground is at least a factor of 2 larger than at 10 m. Therefore, in situ measurements of ICNCs at mountain-top research stations close to the surface are strongly influenced by surface processes and overestimate the ICNC.
Ulrike Lohmann and David Neubauer
Atmos. Chem. Phys., 18, 8807–8828, https://doi.org/10.5194/acp-18-8807-2018, https://doi.org/10.5194/acp-18-8807-2018, 2018
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The climate is warming, at the current rate so much so that the 2 ºC target is likely to be exceeded. Uncertainty remains as to when the 2 ºC of warming will be reached. One factor contributing to this uncertainty is how clouds change in the warmer climate. While previously most emphasis was placed on how low clouds change in the warmer climate, here we investigate the importance of mixed-phase and ice clouds.
Ian Boutle, Jeremy Price, Innocent Kudzotsa, Harri Kokkola, and Sami Romakkaniemi
Atmos. Chem. Phys., 18, 7827–7840, https://doi.org/10.5194/acp-18-7827-2018, https://doi.org/10.5194/acp-18-7827-2018, 2018
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Aerosol processes are a key mechanism in the development of fog. Poor representation of aerosol–fog interaction can result in large biases in fog forecasts, such as surface temperatures which are too high and fog which is too deep and long lived. A relatively simple representation of aerosol–fog interaction can actually lead to significant improvements in forecasting. Aerosol–fog interaction can have a large effect on the climate system but is poorly represented in climate models.
Quentin Bourgeois, Annica M. L. Ekman, Jean-Baptiste Renard, Radovan Krejci, Abhay Devasthale, Frida A.-M. Bender, Ilona Riipinen, Gwenaël Berthet, and Jason L. Tackett
Atmos. Chem. Phys., 18, 7709–7720, https://doi.org/10.5194/acp-18-7709-2018, https://doi.org/10.5194/acp-18-7709-2018, 2018
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The altitude of aerosols is crucial as they can impact cloud formation and radiation. In this study, satellite observations have been used to characterize the global aerosol optical depth (AOD) in the boundary layer and the free troposphere. The free troposphere contributes 39 % to the global AOD during daytime. Overall, the results have implications for the description of budgets, sources, sinks and transport of aerosol particles as presently described in the atmospheric model.
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.
Martin G. Schultz, Scarlet Stadtler, Sabine Schröder, Domenico Taraborrelli, Bruno Franco, Jonathan Krefting, Alexandra Henrot, Sylvaine Ferrachat, Ulrike Lohmann, David Neubauer, Colombe Siegenthaler-Le Drian, Sebastian Wahl, Harri Kokkola, Thomas Kühn, Sebastian Rast, Hauke Schmidt, Philip Stier, Doug Kinnison, Geoffrey S. Tyndall, John J. Orlando, and Catherine Wespes
Geosci. Model Dev., 11, 1695–1723, https://doi.org/10.5194/gmd-11-1695-2018, https://doi.org/10.5194/gmd-11-1695-2018, 2018
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The chemistry–climate model ECHAM-HAMMOZ contains a detailed representation of tropospheric and stratospheric reactive chemistry and state-of-the-art parameterizations of aerosols. It thus allows for detailed investigations of chemical processes in the climate system. Evaluation of the model with various observational data yields good results, but the model has a tendency to produce too much OH in the tropics. This highlights the important interplay between atmospheric chemistry and dynamics.
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.
Remo Dietlicher, David Neubauer, and Ulrike Lohmann
Geosci. Model Dev., 11, 1557–1576, https://doi.org/10.5194/gmd-11-1557-2018, https://doi.org/10.5194/gmd-11-1557-2018, 2018
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A new cloud scheme was implemented in the aerosol–climate model ECHAM6-HAM2. Unlike traditional schemes, it does not categorize ice particles by in-cloud and precipitation types but uses a single category with prognostic bulk particle properties. The new scheme is not only conceptually simpler but also closer to first principles as it does not rely on weakly constrained conversion rates between predefined categories and resolves falling ice by local sub-time-stepping.
Joni-Pekka Pietikäinen, Tiina Markkanen, Kevin Sieck, Daniela Jacob, Johanna Korhonen, Petri Räisänen, Yao Gao, Jaakko Ahola, Hannele Korhonen, Ari Laaksonen, and Jussi Kaurola
Geosci. Model Dev., 11, 1321–1342, https://doi.org/10.5194/gmd-11-1321-2018, https://doi.org/10.5194/gmd-11-1321-2018, 2018
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The regional climate model REMO was coupled with the FLake lake model to include an interactive treatment of lakes. Using this new version, the Fenno-Scandinavian climate and lake characteristics were studied. Our results show that overall the new model version improves the representation of the Fenno-Scandinavian climate in terms of 2 m temperature and precipitation and that the model can reproduce surface water temperature, ice depth and ice season length with reasonably high accuracy.
Antti Lipponen, Tero Mielonen, Mikko R. A. Pitkänen, Robert C. Levy, Virginia R. Sawyer, Sami Romakkaniemi, Ville Kolehmainen, and Antti Arola
Atmos. Meas. Tech., 11, 1529–1547, https://doi.org/10.5194/amt-11-1529-2018, https://doi.org/10.5194/amt-11-1529-2018, 2018
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Atmospheric aerosols are small solid or liquid particles suspended in the atmosphere and they have a significant effect on the climate. Satellite data are used to get global estimates of atmospheric aerosols. In this work, a statistics-based Bayesian aerosol retrieval algorithm was developed to improve the accuracy and quantify the uncertainties related to the aerosol estimates. The algorithm is tested with NASA's Moderate Resolution Imaging Spectroradiometer (MODIS) satellite data.
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
Lauren Marshall, Anja Schmidt, Matthew Toohey, Ken S. Carslaw, Graham W. Mann, Michael Sigl, Myriam Khodri, Claudia Timmreck, Davide Zanchettin, William T. Ball, Slimane Bekki, James S. A. Brooke, Sandip Dhomse, Colin Johnson, Jean-Francois Lamarque, Allegra N. LeGrande, Michael J. Mills, Ulrike Niemeier, James O. Pope, Virginie Poulain, Alan Robock, Eugene Rozanov, Andrea Stenke, Timofei Sukhodolov, Simone Tilmes, Kostas Tsigaridis, and Fiona Tummon
Atmos. Chem. Phys., 18, 2307–2328, https://doi.org/10.5194/acp-18-2307-2018, https://doi.org/10.5194/acp-18-2307-2018, 2018
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We use four global aerosol models to compare the simulated sulfate deposition from the 1815 Mt. Tambora eruption to ice core records. Inter-model volcanic sulfate deposition differs considerably. Volcanic sulfate deposited on polar ice sheets is used to estimate the atmospheric sulfate burden and subsequently radiative forcing of historic eruptions. Our results suggest that deriving such relationships from model simulations may be associated with greater uncertainties than previously thought.
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.
Sylvia C. Sullivan, Corinna Hoose, Alexei Kiselev, Thomas Leisner, and Athanasios Nenes
Atmos. Chem. Phys., 18, 1593–1610, https://doi.org/10.5194/acp-18-1593-2018, https://doi.org/10.5194/acp-18-1593-2018, 2018
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Ice multiplication (IM) processes can have a profound impact on cloud and precipitation development but are poorly understood. Here we study whether a lower limit of ice nuclei exists to initiate IM. The lower limit is found to be extremely low (0.01 per liter or less). A counterintuitive but profound conclusion thus emerges: IM requires cloud formation around a thermodynamic
sweet spotand is sensitive to fluctuations in cloud condensation nuclei concentration alone.
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.
Andreas Kürten, Chenxi Li, Federico Bianchi, Joachim Curtius, António Dias, Neil M. Donahue, Jonathan Duplissy, Richard C. Flagan, Jani Hakala, Tuija Jokinen, Jasper Kirkby, Markku Kulmala, Ari Laaksonen, Katrianne Lehtipalo, Vladimir Makhmutov, Antti Onnela, Matti P. Rissanen, Mario Simon, Mikko Sipilä, Yuri Stozhkov, Jasmin Tröstl, Penglin Ye, and Peter H. McMurry
Atmos. Chem. Phys., 18, 845–863, https://doi.org/10.5194/acp-18-845-2018, https://doi.org/10.5194/acp-18-845-2018, 2018
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A recent laboratory study (CLOUD) showed that new particles nucleate efficiently from sulfuric acid and dimethylamine (DMA). The reanalysis of previously published data reveals that the nucleation rates are even faster than previously assumed, i.e., nucleation can proceed at rates that are compatible with collision-controlled new particle formation for atmospheric conditions. This indicates that sulfuric acid–DMA nucleation is likely an important source of particles in the boundary layer.
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.
Larissa Lacher, Ulrike Lohmann, Yvonne Boose, Assaf Zipori, Erik Herrmann, Nicolas Bukowiecki, Martin Steinbacher, and Zamin A. Kanji
Atmos. Chem. Phys., 17, 15199–15224, https://doi.org/10.5194/acp-17-15199-2017, https://doi.org/10.5194/acp-17-15199-2017, 2017
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We characterize the new Horizontal Ice Nucleation Chamber HINC to measure ambient ice nucleating particle concentrations at mixed‐phase cloud conditions. Results from winter measurements at the High Altitude Research Station Jungfraujoch compare well to previous measurements. We find increased ice nucleating particle concentrations during the influence of Saharan dust events and marine events, which highlights the importance of these species on ice nucleation in the free troposphere.
Luke B. Hande and Corinna Hoose
Atmos. Chem. Phys., 17, 14105–14118, https://doi.org/10.5194/acp-17-14105-2017, https://doi.org/10.5194/acp-17-14105-2017, 2017
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In this study, the relative contributions of different primary ice nucleation modes (i.e. processes leading to the formation of ice crystals with or without the help of certain aerosol particles, in this case mineral dust) are quantified in model simulations for different cloud types.
Elham Baranizadeh, Tuomo Nieminen, Taina Yli-Juuti, Markku Kulmala, Tuukka Petäjä, Ari Leskinen, Mika Komppula, Ari Laaksonen, and Kari E. J. Lehtinen
Atmos. Chem. Phys., 17, 13361–13371, https://doi.org/10.5194/acp-17-13361-2017, https://doi.org/10.5194/acp-17-13361-2017, 2017
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Extrapolation of the particle formation rates from one measured larger size (e.g., 7 nm) to smaller sizes (e.g., 3 nm) based on simplified growth-scavenging dynamics works fairly well to estimate mean daily formation rates, but it fails to predict the time evolution of the particle population. This points to the challenges in predicting atmospheric nucleation rates for locations where the particle growth and loss rates are size- and time-dependent.
Maria Filioglou, Anna Nikandrova, Sami Niemelä, Holger Baars, Tero Mielonen, Ari Leskinen, David Brus, Sami Romakkaniemi, Elina Giannakaki, and Mika Komppula
Atmos. Meas. Tech., 10, 4303–4316, https://doi.org/10.5194/amt-10-4303-2017, https://doi.org/10.5194/amt-10-4303-2017, 2017
David Neubauer, Matthew W. Christensen, Caroline A. Poulsen, and Ulrike Lohmann
Atmos. Chem. Phys., 17, 13165–13185, https://doi.org/10.5194/acp-17-13165-2017, https://doi.org/10.5194/acp-17-13165-2017, 2017
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When aerosol particles take up water their number may seem to be increased optically. However if aerosol particles are removed by precipitation (formation) their numbers will decrease. We applied methods to account for such effects in model and satellite data to analyse the change in cloud properties by changes in aerosol particle number. The agreement of model and satellite data improves when these effects are accounted for.
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.
Hendrik Andersen, Jan Cermak, Julia Fuchs, Reto Knutti, and Ulrike Lohmann
Atmos. Chem. Phys., 17, 9535–9546, https://doi.org/10.5194/acp-17-9535-2017, https://doi.org/10.5194/acp-17-9535-2017, 2017
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Aerosol-cloud interactions continue to contribute large uncertainties to our climate system understanding. In this study, we use near-global satellite and reanalysis data sets to predict marine liquid-water clouds by means of artificial neural networks. We show that on the system scale, lower-tropospheric stability and boundary layer height are the main determinants of liquid-water clouds. Aerosols show the expected impact on clouds but are less relevant than some meteorological factors.
Franziska Glassmeier, Anna Possner, Bernhard Vogel, Heike Vogel, and Ulrike Lohmann
Atmos. Chem. Phys., 17, 8651–8680, https://doi.org/10.5194/acp-17-8651-2017, https://doi.org/10.5194/acp-17-8651-2017, 2017
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We compare two chemistry and aerosol schemes – one designed for air-quality, the other for climate applications. For distribution, composition and radiative properties, the choice of aerosol types and processes turns out to be more important than their implementation. For aerosol–cloud interactions, we find cloud processes, in particular ice formation, to be the main obstacle to our understanding.
Sami Romakkaniemi, Zubair Maalick, Antti Hellsten, Antti Ruuskanen, Olli Väisänen, Irshad Ahmad, Juha Tonttila, Santtu Mikkonen, Mika Komppula, and Thomas Kühn
Atmos. Chem. Phys., 17, 7955–7964, https://doi.org/10.5194/acp-17-7955-2017, https://doi.org/10.5194/acp-17-7955-2017, 2017
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Surface topography affects aerosol–cloud interactions in boundary layer clouds. Local topography effects should be screened out from in situ observations before results can be generalised into a larger scale. Here we present modelling and observational results from a measurement station residing in a 75 m tower on top of a 150 m hill, and analyse how landscape affects the cloud formation, and which factors should be taken into account when aerosol effect on cloud droplet formation is studied.
Anton Laakso, Hannele Korhonen, Sami Romakkaniemi, and Harri Kokkola
Atmos. Chem. Phys., 17, 6957–6974, https://doi.org/10.5194/acp-17-6957-2017, https://doi.org/10.5194/acp-17-6957-2017, 2017
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Based on simulations, equatorial stratospheric sulfur injections have shown to be an efficient strategy to counteract ongoing global warming. However, equatorial injections would result in relatively larger cooling in low latitudes than in high latitudes. This together with greenhouse-gas-induced warming would lead to cooling in the Equator and warming in the high latitudes. Results of this study show that a more optimal cooling effect is achieved by varying the injection area seasonally.
Katharina Loewe, Annica M. L. Ekman, Marco Paukert, Joseph Sedlar, Michael Tjernström, and Corinna Hoose
Atmos. Chem. Phys., 17, 6693–6704, https://doi.org/10.5194/acp-17-6693-2017, https://doi.org/10.5194/acp-17-6693-2017, 2017
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Processes that affect Arctic mixed-phase cloud life cycle are extremely important for the surface energy budget. Three different sensitivity experiments mimic changes in the advection of air masses with different thermodynamic profiles and aerosol properties to find the potential mechanisms leading to the dissipation of the cloud. We found that the reduction of the cloud droplet number concentration was likely the primary contributor to the dissipation of the observed Arctic mixed-phase cloud.
Anahita Amiri-Farahani, Robert J. Allen, David Neubauer, and Ulrike Lohmann
Atmos. Chem. Phys., 17, 6305–6322, https://doi.org/10.5194/acp-17-6305-2017, https://doi.org/10.5194/acp-17-6305-2017, 2017
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We use observations from 2004 to 2012 to obtain estimates of the aerosol–cloud radiative effect, including its uncertainty, for dust aerosol influencing Atlantic marine stratocumulus clouds (MSc) off the coast of north Africa. Saharan dust modifies MSc in a way that acts to cool the planet. There is a strong seasonal variation, with the aerosol–cloud radiative effect switching from significantly negative during the boreal summer to weakly positive during boreal winter.
Hanna Joos, Erica Madonna, Kasja Witlox, Sylvaine Ferrachat, Heini Wernli, and Ulrike Lohmann
Atmos. Chem. Phys., 17, 6243–6255, https://doi.org/10.5194/acp-17-6243-2017, https://doi.org/10.5194/acp-17-6243-2017, 2017
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The influence of pollution on the precipitation formation in warm conveyor belts (WCBs), the most rising air streams in low-pressure systems is investigated. We investigate in detail the cloud properties and resulting precipitation along these rising airstreams which are simulated with a global climate model. Overall, no big impact of aerosols on precipitation can be seen, however, when comparing the most polluted/cleanest WCBs, a suppression of precipitation by aerosols is observed.
Antti Arola, Thomas F. Eck, Harri Kokkola, Mikko R. A. Pitkänen, and Sami Romakkaniemi
Atmos. Chem. Phys., 17, 5991–6001, https://doi.org/10.5194/acp-17-5991-2017, https://doi.org/10.5194/acp-17-5991-2017, 2017
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One of the issues that hinder the measurement-based assessment of aerosol–cloud interactions by remote sensing methods is that typically aerosols and clouds cannot be measured simultaneously by passive remote sensing methods. AERONET includes the SDA product that provides the fine-mode AOD also in mixed cloud–aerosol observations. These measurements have not yet been fully exploited in studies of aerosol–cloud interactions. We applied SDA for this kind of analysis.
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.
Blaž Gasparini, Steffen Münch, Laure Poncet, Monika Feldmann, and Ulrike Lohmann
Atmos. Chem. Phys., 17, 4871–4885, https://doi.org/10.5194/acp-17-4871-2017, https://doi.org/10.5194/acp-17-4871-2017, 2017
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Cirrus clouds have, unlike other cloud types, a warming impact on climate. Decreasing their frequency therefore leads to a cooling effect. Cirrus ice crystals grow larger when formed on solid aerosols, inducing a shorter cloud lifetime.
We compare simplified simulations of stripping cirrus out of the sky with simulations of seeding by aerosol injections. While we find the surface climate responses to be similar, the changes in clouds and cloud properties differ significantly.
David Walters, Ian Boutle, Malcolm Brooks, Thomas Melvin, Rachel Stratton, Simon Vosper, Helen Wells, Keith Williams, Nigel Wood, Thomas Allen, Andrew Bushell, Dan Copsey, Paul Earnshaw, John Edwards, Markus Gross, Steven Hardiman, Chris Harris, Julian Heming, Nicholas Klingaman, Richard Levine, James Manners, Gill Martin, Sean Milton, Marion Mittermaier, Cyril Morcrette, Thomas Riddick, Malcolm Roberts, Claudio Sanchez, Paul Selwood, Alison Stirling, Chris Smith, Dan Suri, Warren Tennant, Pier Luigi Vidale, Jonathan Wilkinson, Martin Willett, Steve Woolnough, and Prince Xavier
Geosci. Model Dev., 10, 1487–1520, https://doi.org/10.5194/gmd-10-1487-2017, https://doi.org/10.5194/gmd-10-1487-2017, 2017
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Global Atmosphere (GA) configurations of the Unified Model (UM) and Global Land (GL) configurations of JULES are developed for use in any global atmospheric modelling application.
We describe a recent iteration of these configurations: GA6/GL6. This includes ENDGame: a new dynamical core designed to improve the model's accuracy, stability and scalability. GA6 is now operational in a variety of Met Office and UM collaborators applications and hence its documentation is important.
We describe a recent iteration of these configurations: GA6/GL6. This includes ENDGame: a new dynamical core designed to improve the model's accuracy, stability and scalability. GA6 is now operational in a variety of Met Office and UM collaborators applications and hence its documentation is important.
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.
Jesús Vergara-Temprado, Benjamin J. Murray, Theodore W. Wilson, Daniel O'Sullivan, Jo Browse, Kirsty J. Pringle, Karin Ardon-Dryer, Allan K. Bertram, Susannah M. Burrows, Darius Ceburnis, Paul J. DeMott, Ryan H. Mason, Colin D. O'Dowd, Matteo Rinaldi, and Ken S. Carslaw
Atmos. Chem. Phys., 17, 3637–3658, https://doi.org/10.5194/acp-17-3637-2017, https://doi.org/10.5194/acp-17-3637-2017, 2017
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We quantify the importance in the atmosphere of different aerosol components to contribute to global ice-nucleating particles concentrations (INPs). The aim is to improve the way atmospheric cloud-ice processes are represented in climate models so they will be able to make better predictions in the future. We found that a kind of dust (K-feldspar), together with marine organic aerosols, can help to improve the representation of INPs and explain most of their observations.
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.
Alexander Beck, Jan Henneberger, Sarah Schöpfer, Jacob Fugal, and Ulrike Lohmann
Atmos. Meas. Tech., 10, 459–476, https://doi.org/10.5194/amt-10-459-2017, https://doi.org/10.5194/amt-10-459-2017, 2017
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In situ observations of cloud properties in complex alpine terrain are commonly conducted at mountain-top research stations and limited to single-point measurements. The HoloGondel platform overcomes this limitation by using a cable car to obtain vertical profiles of the microphysical and meteorological cloud parameters. In this work example measurements of the vertical profiles observed in a liquid cloud and a mixed-phase cloud at the Eggishorn in the Swiss Alps are presented.
Luisa Ickes, André Welti, and Ulrike Lohmann
Atmos. Chem. Phys., 17, 1713–1739, https://doi.org/10.5194/acp-17-1713-2017, https://doi.org/10.5194/acp-17-1713-2017, 2017
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The goal of this study is to find a parameterization scheme for general circulation models to describe immersion freezing with the ability to shift and adjust the slope of the freezing curve compared to homogeneous freezing to match experimental data. We investigated how accurate different formulations of classical nucleation theory reproduce measured immersion freezing curves for different mineral dust types.
Juha Tonttila, Zubair Maalick, Tomi Raatikainen, Harri Kokkola, Thomas Kühn, and Sami Romakkaniemi
Geosci. Model Dev., 10, 169–188, https://doi.org/10.5194/gmd-10-169-2017, https://doi.org/10.5194/gmd-10-169-2017, 2017
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Novel techniques for modelling the aerosol–cloud interactions are implemented in a cloud-resolving model. The new methods improve the representation of the poorly constrained effects of cloud processing, precipitation and the wet removal of particles on the aerosol population and the associated feedbacks. The detailed representation of these processes yields more realistic simulation of the evolution of boundary layer clouds and fogs, as compared to results obtained using more simple methods.
Tomi Raatikainen, David Brus, Rakesh K. Hooda, Antti-Pekka Hyvärinen, Eija Asmi, Ved P. Sharma, Antti Arola, and Heikki Lihavainen
Atmos. Chem. Phys., 17, 371–383, https://doi.org/10.5194/acp-17-371-2017, https://doi.org/10.5194/acp-17-371-2017, 2017
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We have measured black carbon aerosol properties in northern India at two sites: the first site is located at the polluted Indo-Gangetic Plain, while the second site is at the Himalayan foothills in a significantly cleaner environment. The observations show a clear difference in black carbon concentrations, but individual aerosol particles seem to be similar in both sites. Indirect evidence suggests that the particles are highly irregular resembling freshly emitted soot.
Yvonne Boose, André Welti, James Atkinson, Fabiola Ramelli, Anja Danielczok, Heinz G. Bingemer, Michael Plötze, Berko Sierau, Zamin A. Kanji, and Ulrike Lohmann
Atmos. Chem. Phys., 16, 15075–15095, https://doi.org/10.5194/acp-16-15075-2016, https://doi.org/10.5194/acp-16-15075-2016, 2016
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We compare the immersion freezing behavior of four airborne to 11 surface-collected dust samples to investigate the role of different minerals for atmospheric ice nucleation on desert dust. We find that present K-feldspars dominate at T > 253 K, while quartz does at colder temperatures, and surface-collected dust samples are not necessarily representative for airborne dust. For improved ice cloud prediction, modeling of quartz and feldspar emission and transport are key.
Hanna K. Lappalainen, Veli-Matti Kerminen, Tuukka Petäjä, Theo Kurten, Aleksander Baklanov, Anatoly Shvidenko, Jaana Bäck, Timo Vihma, Pavel Alekseychik, Meinrat O. Andreae, Stephen R. Arnold, Mikhail Arshinov, Eija Asmi, Boris Belan, Leonid Bobylev, Sergey Chalov, Yafang Cheng, Natalia Chubarova, Gerrit de Leeuw, Aijun Ding, Sergey Dobrolyubov, Sergei Dubtsov, Egor Dyukarev, Nikolai Elansky, Kostas Eleftheriadis, Igor Esau, Nikolay Filatov, Mikhail Flint, Congbin Fu, Olga Glezer, Aleksander Gliko, Martin Heimann, Albert A. M. Holtslag, Urmas Hõrrak, Juha Janhunen, Sirkku Juhola, Leena Järvi, Heikki Järvinen, Anna Kanukhina, Pavel Konstantinov, Vladimir Kotlyakov, Antti-Jussi Kieloaho, Alexander S. Komarov, Joni Kujansuu, Ilmo Kukkonen, Ella-Maria Duplissy, Ari Laaksonen, Tuomas Laurila, Heikki Lihavainen, Alexander Lisitzin, Alexsander Mahura, Alexander Makshtas, Evgeny Mareev, Stephany Mazon, Dmitry Matishov, Vladimir Melnikov, Eugene Mikhailov, Dmitri Moisseev, Robert Nigmatulin, Steffen M. Noe, Anne Ojala, Mari Pihlatie, Olga Popovicheva, Jukka Pumpanen, Tatjana Regerand, Irina Repina, Aleksei Shcherbinin, Vladimir Shevchenko, Mikko Sipilä, Andrey Skorokhod, Dominick V. Spracklen, Hang Su, Dmitry A. Subetto, Junying Sun, Arkady Y. Terzhevik, Yuri Timofeyev, Yuliya Troitskaya, Veli-Pekka Tynkkynen, Viacheslav I. Kharuk, Nina Zaytseva, Jiahua Zhang, Yrjö Viisanen, Timo Vesala, Pertti Hari, Hans Christen Hansson, Gennady G. Matvienko, Nikolai S. Kasimov, Huadong Guo, Valery Bondur, Sergej Zilitinkevich, and Markku Kulmala
Atmos. Chem. Phys., 16, 14421–14461, https://doi.org/10.5194/acp-16-14421-2016, https://doi.org/10.5194/acp-16-14421-2016, 2016
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After kick off in 2012, the Pan-Eurasian Experiment (PEEX) program has expanded fast and today the multi-disciplinary research community covers ca. 80 institutes and a network of ca. 500 scientists from Europe, Russia, and China. Here we introduce scientific topics relevant in this context. This is one of the first multi-disciplinary overviews crossing scientific boundaries, from atmospheric sciences to socio-economics and social sciences.
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.
François Benduhn, Graham W. Mann, Kirsty J. Pringle, David O. Topping, Gordon McFiggans, and Kenneth S. Carslaw
Geosci. Model Dev., 9, 3875–3906, https://doi.org/10.5194/gmd-9-3875-2016, https://doi.org/10.5194/gmd-9-3875-2016, 2016
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We present a new mathematical formalism that serves to represent exchanges of inorganic matter between the atmosphere gas phase and the aerosol aqueous phase. In a global modelling framework, taking into account these processes may help represent many important features more accurately, such as the formation of cloud droplets or the radiative properties of the atmosphere. The formalism strives to keep an appropriate balance between accuracy and computation efficiency requirements.
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.
Luke B. Hande, Christa Engler, Corinna Hoose, and Ina Tegen
Atmos. Chem. Phys., 16, 12059–12079, https://doi.org/10.5194/acp-16-12059-2016, https://doi.org/10.5194/acp-16-12059-2016, 2016
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An aerosol model was used to simulate the concentration of natural and anthropogenic aerosols over Germany. Using a detailed parameterization of CCN activation, which includes information of aerosol chemical and physical properties, CCN concentrations were calculated. Using these results, a series of best fit functions were used to define a new parameterization, which is a simple function of vertical velocity and pressure. The new parameterization is easy to implement in models.
Elham Baranizadeh, Benjamin N. Murphy, Jan Julin, Saeed Falahat, Carly L. Reddington, Antti Arola, Lars Ahlm, Santtu Mikkonen, Christos Fountoukis, David Patoulias, Andreas Minikin, Thomas Hamburger, Ari Laaksonen, Spyros N. Pandis, Hanna Vehkamäki, Kari E. J. Lehtinen, and Ilona Riipinen
Geosci. Model Dev., 9, 2741–2754, https://doi.org/10.5194/gmd-9-2741-2016, https://doi.org/10.5194/gmd-9-2741-2016, 2016
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The molecular mechanisms through which new ultrafine (< 100 nm) aerosol particles are formed in the atmosphere have puzzled the scientific community for decades. In the past few years, however, significant progress has been made in unraveling these processes through laboratory studies and computational efforts. In this work we have implemented these new developments to an air quality model and study the implications of anthropogenically driven particle formation for European air quality.
Olli Väisänen, Antti Ruuskanen, Arttu Ylisirniö, Pasi Miettinen, Harri Portin, Liqing Hao, Ari Leskinen, Mika Komppula, Sami Romakkaniemi, Kari E. J. Lehtinen, and Annele Virtanen
Atmos. Chem. Phys., 16, 10385–10398, https://doi.org/10.5194/acp-16-10385-2016, https://doi.org/10.5194/acp-16-10385-2016, 2016
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In-cloud measurements of aerosol hygroscopicity and cloud droplet activation were conducted in Kuopio, Finland. According to the observations, the less hygroscopic accumulation mode particles were present in the non-activated aerosol, whereas the more hygroscopic particles were scavenged into cloud droplets. The results illustrate the sensitivity of cloud droplet formation to varying chemical composition and highlight the need for proper treatment of anthropogenic aerosols in CCN predictions.
Yvonne Boose, Berko Sierau, M. Isabel García, Sergio Rodríguez, Andrés Alastuey, Claudia Linke, Martin Schnaiter, Piotr Kupiszewski, Zamin A. Kanji, and Ulrike Lohmann
Atmos. Chem. Phys., 16, 9067–9087, https://doi.org/10.5194/acp-16-9067-2016, https://doi.org/10.5194/acp-16-9067-2016, 2016
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Mineral dust is known to be among the most prevalent ice-nucleating particles (INPs) in the atmosphere, playing a crucial role for ice cloud formation. We present 2 months of ground-based in situ measurements of INP concentrations in the free troposphere close to the largest global dust source, the Sahara. We find that some atmospheric processes such as mixing with biological particles and ammonium increase the dust INP ability. This is important when predicting INPs based on emissions.
Baban Nagare, Claudia Marcolli, André Welti, Olaf Stetzer, and Ulrike Lohmann
Atmos. Chem. Phys., 16, 8899–8914, https://doi.org/10.5194/acp-16-8899-2016, https://doi.org/10.5194/acp-16-8899-2016, 2016
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The relative importance of contact freezing and immersion freezing at mixed-phase cloud temperatures is the subject of debate. We performed experiments using continuous-flow diffusion chambers to compare the freezing efficiency of ice-nucleating particles for both these nucleation modes. Silver iodide, kaolinite and Arizona Test Dust were used as ice-nucleating particles. We could not confirm the dominance of contact freezing over immersion freezing for our experimental conditions.
Claudia Marcolli, Baban Nagare, André Welti, and Ulrike Lohmann
Atmos. Chem. Phys., 16, 8915–8937, https://doi.org/10.5194/acp-16-8915-2016, https://doi.org/10.5194/acp-16-8915-2016, 2016
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Silver iodide is one of the best-investigated ice nuclei. It has relevance for the atmosphere since it is used for glaciogenic cloud seeding. Nevertheless, many open questions remain. This paper gives an overview of silver iodide as an ice nucleus and tries to identify the factors that influence the ice nucleation ability of silver iodide.
Tero Mielonen, Anca Hienola, Thomas Kühn, Joonas Merikanto, Antti Lipponen, Tommi Bergman, Hannele Korhonen, Pekka Kolmonen, Larisa Sogacheva, Darren Ghent, Antti Arola, Gerrit de Leeuw, and Harri Kokkola
Atmos. Chem. Phys. Discuss., https://doi.org/10.5194/acp-2016-625, https://doi.org/10.5194/acp-2016-625, 2016
Revised manuscript not accepted
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We studied the temperature dependence of AOD and its radiative effects over the southeastern US. We used spaceborne observations of AOD, LST and tropospheric NO2 with simulations of ECHAM-HAMMOZ. The level of AOD in this region is governed by anthropogenic emissions but the temperature dependency is most likely caused by BVOC emissions. According to the observations and simulations, the regional clear-sky DRE for biogenic aerosols is −0.43 ± 0.88 W/m2/K and −0.86 ± 0.06 W/m2/K, respectively.
Sarvesh Garimella, Thomas Bjerring Kristensen, Karolina Ignatius, Andre Welti, Jens Voigtländer, Gourihar R. Kulkarni, Frank Sagan, Gregory Lee Kok, James Dorsey, Leonid Nichman, Daniel Alexander Rothenberg, Michael Rösch, Amélie Catharina Ruth Kirchgäßner, Russell Ladkin, Heike Wex, Theodore W. Wilson, Luis Antonio Ladino, Jon P. D. Abbatt, Olaf Stetzer, Ulrike Lohmann, Frank Stratmann, and Daniel James Cziczo
Atmos. Meas. Tech., 9, 2781–2795, https://doi.org/10.5194/amt-9-2781-2016, https://doi.org/10.5194/amt-9-2781-2016, 2016
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The SPectrometer for Ice Nuclei (SPIN) is a commercially available ice nuclei counter manufactured by Droplet Measurement Technologies in Boulder, CO. This study characterizes the SPIN chamber, reporting data from laboratory measurements and quantifying uncertainties. Overall, we report that the SPIN is able to reproduce previous CFDC ice nucleation measurements.
Kimiko M. Sakamoto, James R. Laing, Robin G. Stevens, Daniel A. Jaffe, and Jeffrey R. Pierce
Atmos. Chem. Phys., 16, 7709–7724, https://doi.org/10.5194/acp-16-7709-2016, https://doi.org/10.5194/acp-16-7709-2016, 2016
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We determine how various meteorological and fire factors contribute to shaping the aged biomass-burning particle size distribution through coagulation. The mass emissions flux, fire area, and wind speed are dominant factors controlling the aged size distribution. We parameterize the aged size distribution for global/regional aerosol models. We estimate that the aged biomass-burning particle size distribution may be more sensitive to variability in coagulation than SOA formation.
Robert J. Farrington, Paul J. Connolly, Gary Lloyd, Keith N. Bower, Michael J. Flynn, Martin W. Gallagher, Paul R. Field, Chris Dearden, and Thomas W. Choularton
Atmos. Chem. Phys., 16, 4945–4966, https://doi.org/10.5194/acp-16-4945-2016, https://doi.org/10.5194/acp-16-4945-2016, 2016
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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.
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.
Shipeng Zhang, Minghuai Wang, Steven J. Ghan, Aijun Ding, Hailong Wang, Kai Zhang, David Neubauer, Ulrike Lohmann, Sylvaine Ferrachat, Toshihiko Takeamura, Andrew Gettelman, Hugh Morrison, Yunha Lee, Drew T. Shindell, Daniel G. Partridge, Philip Stier, Zak Kipling, and Congbin Fu
Atmos. Chem. Phys., 16, 2765–2783, https://doi.org/10.5194/acp-16-2765-2016, https://doi.org/10.5194/acp-16-2765-2016, 2016
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The variation of aerosol indirect effects (AIE) in several climate models is investigated across different dynamical regimes. Regimes with strong large-scale ascent are shown to be as important as stratocumulus regimes in studying AIE. AIE over regions with high monthly large-scale surface precipitation rate contributes the most to the total aerosol indirect forcing. These results point to the need to reduce the uncertainty in AIE in different dynamical regimes.
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.
Jenni Kontkanen, Emma Järvinen, Hanna E. Manninen, Katrianne Lehtipalo, Juha Kangasluoma, Stefano Decesari, Gian Paolo Gobbi, Ari Laaksonen, Tuukka Petäjä, and Markku Kulmala
Atmos. Chem. Phys., 16, 1919–1935, https://doi.org/10.5194/acp-16-1919-2016, https://doi.org/10.5194/acp-16-1919-2016, 2016
F. Höpner, F. A.-M. Bender, A. M. L. Ekman, P. S. Praveen, C. Bosch, J. A. Ogren, A. Andersson, Ö. Gustafsson, and V. Ramanathan
Atmos. Chem. Phys., 16, 1045–1064, https://doi.org/10.5194/acp-16-1045-2016, https://doi.org/10.5194/acp-16-1045-2016, 2016
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The paper presents aerosol properties measured during the Cloud Aerosol Radiative Forcing Experiment (CARDEX) on the Maldives Islands in winter 2012. The vertical distribution of absorbing aerosol which is very relevant to the radiative forcing in that region, is investigated. A method for determining particle absorption and equivalent black carbon concentration from lidar extinction coefficients, characteristic single scattering albedo and mass absorption efficiency, is presented and evaluated.
J. Kim, L. Ahlm, T. Yli-Juuti, M. Lawler, H. Keskinen, J. Tröstl, S. Schobesberger, J. Duplissy, A. Amorim, F. Bianchi, N. M. Donahue, R. C. Flagan, J. Hakala, M. Heinritzi, T. Jokinen, A. Kürten, A. Laaksonen, K. Lehtipalo, P. Miettinen, T. Petäjä, M. P. Rissanen, L. Rondo, K. Sengupta, M. Simon, A. Tomé, C. Williamson, D. Wimmer, P. M. Winkler, S. Ehrhart, P. Ye, J. Kirkby, J. Curtius, U. Baltensperger, M. Kulmala, K. E. J. Lehtinen, J. N. Smith, I. Riipinen, and A. Virtanen
Atmos. Chem. Phys., 16, 293–304, https://doi.org/10.5194/acp-16-293-2016, https://doi.org/10.5194/acp-16-293-2016, 2016
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The hygroscopicity of nucleated nanoparticles was measured in the presence of sulfuric acid, sulfuric acid-dimethylamine, and sulfuric acid-organics derived from α-pinene oxidation during CLOUD7 at CERN in 2012. The hygroscopicity parameter κ decreased with increasing particle size, indicating decreasing acidity of particles.
A. Laakso, H. Kokkola, A.-I. Partanen, U. Niemeier, C. Timmreck, K. E. J. Lehtinen, H. Hakkarainen, and H. Korhonen
Atmos. Chem. Phys., 16, 305–323, https://doi.org/10.5194/acp-16-305-2016, https://doi.org/10.5194/acp-16-305-2016, 2016
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We have studied the impacts of a volcanic eruption during solar radiation management (SRM) using an aerosol-climate model ECHAM5-HAM-SALSA and an Earth system model MPI-ESM. A volcanic eruption during stratospheric sulfur geoengineering would lead to larger particles and smaller amount of new particles than if an volcano erupts in normal atmospheric conditions. Thus, volcanic eruption during SRM would lead to only a small additional cooling which would last for a significantly shorter period.
A. Laaksonen and J. Malila
Atmos. Chem. Phys., 16, 135–143, https://doi.org/10.5194/acp-16-135-2016, https://doi.org/10.5194/acp-16-135-2016, 2016
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Heterogeneous nucleation is a phenomenon that starts the condensation of supersaturated vapours on solid surfaces. An example is the formation of cirrus clouds in the atmosphere: their formation is often triggered at relative humidities clearly above 100%. We derive a new theory that can be used to calculate the threshold supersaturation of heterogeneous nucleation of water vapour on nanoparticles and show that it performs significantly better than older theories when compared to lab experiment.
A. M. K. Hansen, J. Hong, T. Raatikainen, K. Kristensen, A. Ylisirniö, A. Virtanen, T. Petäjä, M. Glasius, and N. L. Prisle
Atmos. Chem. Phys., 15, 14071–14089, https://doi.org/10.5194/acp-15-14071-2015, https://doi.org/10.5194/acp-15-14071-2015, 2015
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This paper presents the first study of the hygroscopic properties of limonene derived organosulfates (L-OS 250). The results showed that L-OS 250 particles are weakly hygroscopic and able to activate into cloud droplets. Particles of L-OS 250 mixed with ammonium sulfate were much more hygroscopic than expected from model parametrizations and the ZSR mixing rule, indicating that solubility and non-ideal droplet interactions could be important for the hygroscopic properties of the mixed particles.
B. Nagare, C. Marcolli, O. Stetzer, and U. Lohmann
Atmos. Chem. Phys., 15, 13759–13776, https://doi.org/10.5194/acp-15-13759-2015, https://doi.org/10.5194/acp-15-13759-2015, 2015
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We determined collision efficiencies of cloud droplets with aerosol particles experimentally and found that they were around 1 order of magnitude higher than theoretical formulations that include Brownian diffusion, impaction, interception, thermophoretic, diffusiophoretic and electric forces. This is most probably due to uncertainties and inaccuracies in the theoretical formulations of thermophoretic and diffusiophoretic processes.
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.
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.
C. E. Scott, D. V. Spracklen, J. R. Pierce, I. Riipinen, S. D. D'Andrea, A. Rap, K. S. Carslaw, P. M. Forster, P. Artaxo, M. Kulmala, L. V. Rizzo, E. Swietlicki, G. W. Mann, and K. J. Pringle
Atmos. Chem. Phys., 15, 12989–13001, https://doi.org/10.5194/acp-15-12989-2015, https://doi.org/10.5194/acp-15-12989-2015, 2015
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To understand the radiative effects of biogenic secondary organic aerosol (SOA) it is necessary to consider the manner in which it is distributed across the existing aerosol size distribution. We explore the importance of the approach taken by global-scale models to do this, when calculating the direct radiative effect (DRE) & first aerosol indirect effect (AIE) due to biogenic SOA. This choice has little effect on the DRE, but a substantial impact on the magnitude and even sign of the first AIE
A. Arola, G. L. Schuster, M. R. A. Pitkänen, O. Dubovik, H. Kokkola, A. V. Lindfors, T. Mielonen, T. Raatikainen, S. Romakkaniemi, S. N. Tripathi, and H. Lihavainen
Atmos. Chem. Phys., 15, 12731–12740, https://doi.org/10.5194/acp-15-12731-2015, https://doi.org/10.5194/acp-15-12731-2015, 2015
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There have been relatively few measurement-based estimates for the direct radiative effect of brown carbon so far. This is first time that the direct radiative effect of brown carbon is estimated by exploiting the AERONET-retrieved imaginary indices. We estimated it for four sites in the Indo-Gangetic Plain: Karachi, Lahore,
Kanpur and Gandhi College.
C. Barthlott and C. Hoose
Atmos. Chem. Phys., 15, 12361–12384, https://doi.org/10.5194/acp-15-12361-2015, https://doi.org/10.5194/acp-15-12361-2015, 2015
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This paper assesses the resolution dependance of clouds and precipitation over Germany by numerical simulations with the COnsortium for Small-scale MOdeling model for 7 cases of 2013. By means of a series of grid-refinement resolution tests, the variability of clouds and precipitation and how this variability changes with model resolution are investigated. The performance of the model at these resolutions is of general relevance to the research community as well as to operational forecasters
M. Paramonov, V.-M. Kerminen, M. Gysel, P. P. Aalto, M. O. Andreae, E. Asmi, U. Baltensperger, A. Bougiatioti, D. Brus, G. P. Frank, N. Good, S. S. Gunthe, L. Hao, M. Irwin, A. Jaatinen, Z. Jurányi, S. M. King, A. Kortelainen, A. Kristensson, H. Lihavainen, M. Kulmala, U. Lohmann, S. T. Martin, G. McFiggans, N. Mihalopoulos, A. Nenes, C. D. O'Dowd, J. Ovadnevaite, T. Petäjä, U. Pöschl, G. C. Roberts, D. Rose, B. Svenningsson, E. Swietlicki, E. Weingartner, J. Whitehead, A. Wiedensohler, C. Wittbom, and B. Sierau
Atmos. Chem. Phys., 15, 12211–12229, https://doi.org/10.5194/acp-15-12211-2015, https://doi.org/10.5194/acp-15-12211-2015, 2015
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The research paper presents the first comprehensive overview of field measurements with the CCN Counter performed at a large number of locations around the world within the EUCAARI framework. The paper sheds light on the CCN number concentrations and activated fractions around the world and their dependence on the water vapour supersaturation ratio, the dependence of aerosol hygroscopicity on particle size, and seasonal and diurnal variation of CCN activation and hygroscopic properties.
J. C. Corbin, A. Othman, J. D. Allan, D. R. Worsnop, J. D. Haskins, B. Sierau, U. Lohmann, and A. A. Mensah
Atmos. Meas. Tech., 8, 4615–4636, https://doi.org/10.5194/amt-8-4615-2015, https://doi.org/10.5194/amt-8-4615-2015, 2015
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Peak-integration uncertainties in the Aerodyne high-resolution aerosol mass spectrometer (AMS) are analyzed in detail using a combination of empirical data analysis and Monte Carlo approaches. The most general conclusion, applicable to any mass spectrometer, is that non-zero mass accuracy leads to a percentage error in constrained peak fits, even for well-resolved peaks. For overlapping peaks, this mass-accuracy effect may be viewed as a reduction in the effective m/z-calibration precision.
J. Joutsensaari, P. Yli-Pirilä, H. Korhonen, A. Arola, J. D. Blande, J. Heijari, M. Kivimäenpää, S. Mikkonen, L. Hao, P. Miettinen, P. Lyytikäinen-Saarenmaa, C. L. Faiola, A. Laaksonen, and J. K. Holopainen
Atmos. Chem. Phys., 15, 12139–12157, https://doi.org/10.5194/acp-15-12139-2015, https://doi.org/10.5194/acp-15-12139-2015, 2015
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Global warming will induce large-scale insect outbreaks in boreal forests. Our results from field and laboratory experiments, satellite observations and global-scale modelling suggest that more frequent insect outbreaks, in addition to temperature-dependent increases in VOC emissions, could result in substantial increases in biogenic SOA formation and therefore affect both aerosol direct and indirect forcing of climate at regional scales. This should be considered in future climate predictions.
J. C. Corbin, U. Lohmann, B. Sierau, A. Keller, H. Burtscher, and A. A. Mensah
Atmos. Chem. Phys., 15, 11885–11907, https://doi.org/10.5194/acp-15-11885-2015, https://doi.org/10.5194/acp-15-11885-2015, 2015
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The chemical composition of wood-combustion soot is investigated using a soot-particle aerosol mass spectrometer. The analysis elucidates real-time information on BC oxygenated surface functional groups for a real-world source for the first time. Additional insights into the source of organic material in this soot are provided by positive matrix factorization of the data using a new AMS error model.
E. Johansson, A. Devasthale, T. L'Ecuyer, A. M. L. Ekman, and M. Tjernström
Atmos. Chem. Phys., 15, 11557–11570, https://doi.org/10.5194/acp-15-11557-2015, https://doi.org/10.5194/acp-15-11557-2015, 2015
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Both radiative and latent heat components of total diabatic heating influence Indian monsoon dynamics. This study investigates radiative component in detail, focusing on various cloud types that have largest radiative impact during summer monsoon over the Indian subcontinent. The vertical structure of radiative heating and its intra-seasonal variability is investigated with particular emphasis on the upper troposphere and lower stratosphere (UTLS) region.
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
E. Hammer, N. Bukowiecki, B. P. Luo, U. Lohmann, C. Marcolli, E. Weingartner, U. Baltensperger, and C. R. Hoyle
Atmos. Chem. Phys., 15, 10309–10323, https://doi.org/10.5194/acp-15-10309-2015, https://doi.org/10.5194/acp-15-10309-2015, 2015
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An important quantity which determines aerosol activation and cloud formation is the effective peak supersaturation. The box model ZOMM was used to simulate the effective peak supersaturation experienced by an air parcel approaching a high-alpine research station in Switzerland. With the box model the sensitivity of the effective peak supersaturation to key aerosol and dynamical parameters was investigated.
T. Raatikainen, D. Brus, A.-P. Hyvärinen, J. Svensson, E. Asmi, and H. Lihavainen
Atmos. Chem. Phys., 15, 10057–10070, https://doi.org/10.5194/acp-15-10057-2015, https://doi.org/10.5194/acp-15-10057-2015, 2015
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We have measured atmospheric aerosol composition by using a Single Particle Soot Photometer (SP2) in the Finnish Arctic during winter 2011-2012. SP2 can give detailed information about mass distributions and mixing state of refractory black carbon (rBC). The measurements showed varying rBC mass concentrations, but relatively constant rBC core size distributions and mixing state parameters. On average, 24% of all particles contain rBC and the observed rBC cores are always thickly coated.
S. T. Turnock, D. V. Spracklen, K. S. Carslaw, G. W. Mann, M. T. Woodhouse, P. M. Forster, J. Haywood, C. E. Johnson, M. Dalvi, N. Bellouin, and A. Sanchez-Lorenzo
Atmos. Chem. Phys., 15, 9477–9500, https://doi.org/10.5194/acp-15-9477-2015, https://doi.org/10.5194/acp-15-9477-2015, 2015
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We evaluate HadGEM3-UKCA over Europe for the period 1960-2009 against observations of aerosol mass and number, aerosol optical depth (AOD) and surface solar radiation (SSR). The model underestimates aerosol mass and number but is less biased if compared to AOD and SSR. Observed trends in aerosols are well simulated by the model and necessary for reproducing the observed increase in SSR since 1990. European all-sky top of atmosphere aerosol radiative forcing increased by > 3 Wm-2 from 1970 to 2009.
S. Pousse-Nottelmann, E. M. Zubler, and U. Lohmann
Atmos. Chem. Phys., 15, 9217–9236, https://doi.org/10.5194/acp-15-9217-2015, https://doi.org/10.5194/acp-15-9217-2015, 2015
V. Sant, R. Posselt, and U. Lohmann
Atmos. Chem. Phys., 15, 8717–8738, https://doi.org/10.5194/acp-15-8717-2015, https://doi.org/10.5194/acp-15-8717-2015, 2015
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We have introduced prognostic precipitation for both liquid (drizzle and rain) and solid (snow) phase precipitation into the global circulation model ECHAM5-HAM. This has a significant effect on the clouds and the parameterized collection rates, also reducing the sensitivity of the liquid water path to the anthropogenic aerosol forcing. Altogether the results suggest that the treatment of precipitation in global circulation models has a significant influence on the phase and lifetime of clouds.
S. Fuzzi, U. Baltensperger, K. Carslaw, S. Decesari, H. Denier van der Gon, M. C. Facchini, D. Fowler, I. Koren, B. Langford, U. Lohmann, E. Nemitz, S. Pandis, I. Riipinen, Y. Rudich, M. Schaap, J. G. Slowik, D. V. Spracklen, E. Vignati, M. Wild, M. Williams, and S. Gilardoni
Atmos. Chem. Phys., 15, 8217–8299, https://doi.org/10.5194/acp-15-8217-2015, https://doi.org/10.5194/acp-15-8217-2015, 2015
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Particulate matter (PM) constitutes one of the most challenging problems both for air quality and climate change policies. This paper reviews the most recent scientific results on the issue and the policy needs that have driven much of the increase in monitoring and mechanistic research over the last 2 decades. The synthesis reveals many new processes and developments in the science underpinning climate-PM interactions and the effects of PM on human health and the environment.
A. Franchin, S. Ehrhart, J. Leppä, T. Nieminen, S. Gagné, S. Schobesberger, D. Wimmer, J. Duplissy, F. Riccobono, E. M. Dunne, L. Rondo, A. Downard, F. Bianchi, A. Kupc, G. Tsagkogeorgas, K. Lehtipalo, H. E. Manninen, J. Almeida, A. Amorim, P. E. Wagner, A. Hansel, J. Kirkby, A. Kürten, N. M. Donahue, V. Makhmutov, S. Mathot, A. Metzger, T. Petäjä, R. Schnitzhofer, M. Sipilä, Y. Stozhkov, A. Tomé, V.-M. Kerminen, K. Carslaw, J. Curtius, U. Baltensperger, and M. Kulmala
Atmos. Chem. Phys., 15, 7203–7216, https://doi.org/10.5194/acp-15-7203-2015, https://doi.org/10.5194/acp-15-7203-2015, 2015
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The ion-ion recombination coefficient was measured at different temperatures, relative humidities and concentrations of ozone and sulfur dioxide. The experiments were carried out using the CLOUD chamber at CERN.
We observed a strong dependency on temperature and on relative humidity, which has not been reported previously. No dependency of the ion-ion recombination coefficient on ozone concentration was observed and a weak variation with sulfur dioxide concentration was also observed.
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. Tonttila, E. J. O'Connor, A. Hellsten, A. Hirsikko, C. O'Dowd, H. Järvinen, and P. Räisänen
Atmos. Chem. Phys., 15, 5873–5885, https://doi.org/10.5194/acp-15-5873-2015, https://doi.org/10.5194/acp-15-5873-2015, 2015
J.-P. Pietikäinen, K. Kupiainen, Z. Klimont, R. Makkonen, H. Korhonen, R. Karinkanta, A.-P. Hyvärinen, N. Karvosenoja, A. Laaksonen, H. Lihavainen, and V.-M. Kerminen
Atmos. Chem. Phys., 15, 5501–5519, https://doi.org/10.5194/acp-15-5501-2015, https://doi.org/10.5194/acp-15-5501-2015, 2015
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The global aerosol--climate model ECHAM-HAMMOZ is used to study the aerosol burden and forcing changes in the coming decades. We show that aerosol burdens overall can have a decreasing trend leading to reductions in the direct aerosol effect being globally 0.06--0.4W/m2 by 2030, whereas the aerosol indirect radiative effect could decline 0.25--0.82W/m2. We also show that the targeted emission reduction measures can be a much better choice for the climate than overall high reductions globally.
L. B. Hande, C. Engler, C. Hoose, and I. Tegen
Atmos. Chem. Phys., 15, 4389–4397, https://doi.org/10.5194/acp-15-4389-2015, https://doi.org/10.5194/acp-15-4389-2015, 2015
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Dust is a significant aerosol on seasonal timescales. There are large differences in dust and INP concentrations between seasons. The INP concentrations have a different vertical distribution than other common parameterisations suggest. We provide a new formulation to estimate the INP particles formed on dust aerosols, for use in process studies and regional simulations over Europe. The new formulation captures a much more realistic seasonal variability and vertical profile.
B. J. Shipway
Atmos. Chem. Phys., 15, 3803–3814, https://doi.org/10.5194/acp-15-3803-2015, https://doi.org/10.5194/acp-15-3803-2015, 2015
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A new parametrization for cloud droplet nucleation is described. This revised approach makes use of a simple look-up table which is very efficient and computationally very cheap. Adopting this approach further allows for a more accurate treatment of the necessary approximations of supersaturation evolution and ultimately leads to a more accurate calculation of peak supersaturation and hence droplet nucleation.
M. Dalirian, H. Keskinen, L. Ahlm, A. Ylisirniö, S. Romakkaniemi, A. Laaksonen, A. Virtanen, and I. Riipinen
Atmos. Chem. Phys., 15, 3815–3829, https://doi.org/10.5194/acp-15-3815-2015, https://doi.org/10.5194/acp-15-3815-2015, 2015
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.
A. Possner, E. Zubler, U. Lohmann, and C. Schär
Atmos. Chem. Phys., 15, 2185–2201, https://doi.org/10.5194/acp-15-2185-2015, https://doi.org/10.5194/acp-15-2185-2015, 2015
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For the first time, real-case simulations of ship tracks are performed at the 2km scale and evaluated against observations. Simulations show that ship tracks are quantitatively and qualitatively captured by the model. Therefore, this approach could be used to evaluate the interplay between parameterisations for aerosol–cloud interactions which occur, in the case of ship tracks, in spatially defined regions and under constrained environmental 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
C. Andersson, R. Bergström, C. Bennet, L. Robertson, M. Thomas, H. Korhonen, K. E. J. Lehtinen, and H. Kokkola
Geosci. Model Dev., 8, 171–189, https://doi.org/10.5194/gmd-8-171-2015, https://doi.org/10.5194/gmd-8-171-2015, 2015
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We have integrated the sectional aerosol dynamics model SALSA into the European scale chemistry-transport model MATCH. The combined model reproduces observed higher particle number concentration (PNCs) in central Europe and lower concentrations in remote regions; however, the total PNC is underestimated. The low nucleation rate coefficient used in this study is an important reason for the underestimation.
J. Tonttila, H. Järvinen, and P. Räisänen
Atmos. Chem. Phys., 15, 703–714, https://doi.org/10.5194/acp-15-703-2015, https://doi.org/10.5194/acp-15-703-2015, 2015
S. Schobesberger, A. Franchin, F. Bianchi, L. Rondo, J. Duplissy, A. Kürten, I. K. Ortega, A. Metzger, R. Schnitzhofer, J. Almeida, A. Amorim, J. Dommen, E. M. Dunne, M. Ehn, S. Gagné, L. Ickes, H. Junninen, A. Hansel, V.-M. Kerminen, J. Kirkby, A. Kupc, A. Laaksonen, K. Lehtipalo, S. Mathot, A. Onnela, T. Petäjä, F. Riccobono, F. D. Santos, M. Sipilä, A. Tomé, G. Tsagkogeorgas, Y. Viisanen, P. E. Wagner, D. Wimmer, J. Curtius, N. M. Donahue, U. Baltensperger, M. Kulmala, and D. R. Worsnop
Atmos. Chem. Phys., 15, 55–78, https://doi.org/10.5194/acp-15-55-2015, https://doi.org/10.5194/acp-15-55-2015, 2015
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We used an ion mass spectrometer at CERN's CLOUD chamber to investigate the detailed composition of ammonia--sulfuric acid ion clusters (of both polarities) as they initially form and then grow into aerosol particles, at atmospherically relevant conditions. We found that these clusters’ composition is mainly determined by the ratio of the precursor vapors and ranges from ammonia-free clusters to clusters containing > 1 ammonia per sulfuric acid. Acid--base bindings are a key formation mechanism.
R. G. Stevens and J. R. Pierce
Atmos. Chem. Phys., 14, 13661–13679, https://doi.org/10.5194/acp-14-13661-2014, https://doi.org/10.5194/acp-14-13661-2014, 2014
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We implement a parameterization of sub-grid new-particle formation in sulfur-rich plumes (P6) for the first time into a global chemical-transport model with online aerosol microphysics. Compared with previous treatments of sub-grid particle formation, use of the P6 parameterization limits sub-grid particle formation in polluted or low-sunlight regions. We also test the sensitivity of sub-grid particle formation to changes in SO2 or NOx emissions due to emissions controls.
E. M. Dunne, S. Mikkonen, H. Kokkola, and H. Korhonen
Atmos. Chem. Phys., 14, 13631–13642, https://doi.org/10.5194/acp-14-13631-2014, https://doi.org/10.5194/acp-14-13631-2014, 2014
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Marine clouds have a strong effect on the Earth's radiative balance. One proposed climate feedback is that, in a warming climate, marine aerosol emissions will change due to changing wind speeds. We have examined the processes that affect aerosol emissions and removal over 15 years, and high-temporal-resolution output over 2 months. We conclude that wind trends are unlikely to cause a strong feedback in marine regions, but changes in removal processes or transport from continental regions may.
L. Q. Hao, A. Kortelainen, S. Romakkaniemi, H. Portin, A. Jaatinen, A. Leskinen, M. Komppula, P. Miettinen, D. Sueper, A. Pajunoja, J. N. Smith, K. E. J. Lehtinen, D. R. Worsnop, A. Laaksonen, and A. Virtanen
Atmos. Chem. Phys., 14, 13483–13495, https://doi.org/10.5194/acp-14-13483-2014, https://doi.org/10.5194/acp-14-13483-2014, 2014
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Positive matrix factorization (PMF) was applied to the unified high-resolution mass spectra organic species with NO+ and NO2+ ions from the measurement in a mixed region between the boreal forestland and the urban area. The PMF analysis succeeded in separating the mixed spectra into three distinct organic factors and one inorganic factor. The particulate organic nitrate was distinguished by PMF for the first time, with a contribution of one-third of the total nitrate mass.
P. Räisänen, A. Luomaranta, H. Järvinen, M. Takala, K. Jylhä, O. N. Bulygina, K. Luojus, A. Riihelä, A. Laaksonen, J. Koskinen, and J. Pulliainen
Geosci. Model Dev., 7, 3037–3057, https://doi.org/10.5194/gmd-7-3037-2014, https://doi.org/10.5194/gmd-7-3037-2014, 2014
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Snowmelt influences greatly the climatic conditions in spring. This study evaluates the timing of springtime end of snowmelt in the ECHAM5 model. A key finding is that, in much of northern Eurasia, snow disappears too early in ECHAM5, in spite of a slight cold bias in spring. This points to the need for a more comprehensive treatment of the surface energy budget. In particular, the surface temperature for the snow-covered and snow-free parts of a climate model grid cell should be separated.
Y. Gao, T. Markkanen, L. Backman, H. M. Henttonen, J.-P. Pietikäinen, H. M. Mäkelä, and A. Laaksonen
Biogeosciences, 11, 7251–7267, https://doi.org/10.5194/bg-11-7251-2014, https://doi.org/10.5194/bg-11-7251-2014, 2014
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This work studies the biogeophysical impacts of peatland forestation on regional climate conditions in Finland by a regional climate model with two land cover maps produced from Finnish national forest inventories. A warming in spring and a slight cooling in the growing season are found in peatland forestation area, which are mainly induced by the decreased surface albedo and increased ET, respectively. The snow clearance days are advanced. The results are also compared with observational data.
N. Hiranuma, M. Paukert, I. Steinke, K. Zhang, G. Kulkarni, C. Hoose, M. Schnaiter, H. Saathoff, and O. Möhler
Atmos. Chem. Phys., 14, 13145–13158, https://doi.org/10.5194/acp-14-13145-2014, https://doi.org/10.5194/acp-14-13145-2014, 2014
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A new heterogeneous ice nucleation parameterization is developed and implemented in cloud models. The results of our simulations suggest stronger influence of dust particles lifted to the upper troposphere on heterogeneous nucleation and more ice nucleation at temperature and humidity conditions relevant to both mixed-phase and cirrus clouds when compared to the existing parametrical frameworks.
D. Neubauer, U. Lohmann, C. Hoose, and M. G. Frontoso
Atmos. Chem. Phys., 14, 11997–12022, https://doi.org/10.5194/acp-14-11997-2014, https://doi.org/10.5194/acp-14-11997-2014, 2014
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Several biases in the representation of clouds in the stratocumulus regime in the ECHAM6-HAM2 global climate model were found by evaluating the model in the stratocumulus cloud regime. Simulations with changes in model resolution and physics to better represent clouds and aerosol in the stratocumulus regime show that the human influence on clouds and thus climate by emission of aerosol particles is sensitive to the representation of (stratocumulus) clouds.
J.-P. Pietikäinen, S. Mikkonen, A. Hamed, A. I. Hienola, W. Birmili, M. Kulmala, and A. Laaksonen
Atmos. Chem. Phys., 14, 11711–11729, https://doi.org/10.5194/acp-14-11711-2014, https://doi.org/10.5194/acp-14-11711-2014, 2014
A.-I. Partanen, E. M. Dunne, T. Bergman, A. Laakso, H. Kokkola, J. Ovadnevaite, L. Sogacheva, D. Baisnée, J. Sciare, A. Manders, C. O'Dowd, G. de Leeuw, and H. Korhonen
Atmos. Chem. Phys., 14, 11731–11752, https://doi.org/10.5194/acp-14-11731-2014, https://doi.org/10.5194/acp-14-11731-2014, 2014
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New parameterizations for the sea spray aerosol source flux and its organic fraction were incorporated into a global aerosol-climate model. The emissions of sea salt were considerably less than previous estimates. This study demonstrates that sea spray aerosol may actually decrease the number of cloud droplets, which has a warming effect on climate. Overall, sea spray aerosol was predicted to have a global cooling effect due to the scattering of solar radiation from sea spray aerosol particles.
S. S. Dhomse, K. M. Emmerson, G. W. Mann, N. Bellouin, K. S. Carslaw, M. P. Chipperfield, R. Hommel, N. L. Abraham, P. Telford, P. Braesicke, M. Dalvi, C. E. Johnson, F. O'Connor, O. Morgenstern, J. A. Pyle, T. Deshler, J. M. Zawodny, and L. W. Thomason
Atmos. Chem. Phys., 14, 11221–11246, https://doi.org/10.5194/acp-14-11221-2014, https://doi.org/10.5194/acp-14-11221-2014, 2014
K. Tsigaridis, N. Daskalakis, M. Kanakidou, P. J. Adams, P. Artaxo, R. Bahadur, Y. Balkanski, S. E. Bauer, N. Bellouin, A. Benedetti, T. Bergman, T. K. Berntsen, J. P. Beukes, H. Bian, K. S. Carslaw, M. Chin, G. Curci, T. Diehl, R. C. Easter, S. J. Ghan, S. L. Gong, A. Hodzic, C. R. Hoyle, T. Iversen, S. Jathar, J. L. Jimenez, J. W. Kaiser, A. Kirkevåg, D. Koch, H. Kokkola, Y. H Lee, G. Lin, X. Liu, G. Luo, X. Ma, G. W. Mann, N. Mihalopoulos, J.-J. Morcrette, J.-F. Müller, G. Myhre, S. Myriokefalitakis, N. L. Ng, D. O'Donnell, J. E. Penner, L. Pozzoli, K. J. Pringle, L. M. Russell, M. Schulz, J. Sciare, Ø. Seland, D. T. Shindell, S. Sillman, R. B. Skeie, D. Spracklen, T. Stavrakou, S. D. Steenrod, T. Takemura, P. Tiitta, S. Tilmes, H. Tost, T. van Noije, P. G. van Zyl, K. von Salzen, F. Yu, Z. Wang, Z. Wang, R. A. Zaveri, H. Zhang, K. Zhang, Q. Zhang, and X. Zhang
Atmos. Chem. Phys., 14, 10845–10895, https://doi.org/10.5194/acp-14-10845-2014, https://doi.org/10.5194/acp-14-10845-2014, 2014
Y. Wang, X. Liu, C. Hoose, and B. Wang
Atmos. Chem. Phys., 14, 10411–10430, https://doi.org/10.5194/acp-14-10411-2014, https://doi.org/10.5194/acp-14-10411-2014, 2014
S. V. Henriksson, J.-P. Pietikäinen, A.-P. Hyvärinen, P. Räisänen, K. Kupiainen, J. Tonttila, R. Hooda, H. Lihavainen, D. O'Donnell, L. Backman, Z. Klimont, and A. Laaksonen
Atmos. Chem. Phys., 14, 10177–10192, https://doi.org/10.5194/acp-14-10177-2014, https://doi.org/10.5194/acp-14-10177-2014, 2014
M. Joly, P. Amato, L. Deguillaume, M. Monier, C. Hoose, and A.-M. Delort
Atmos. Chem. Phys., 14, 8185–8195, https://doi.org/10.5194/acp-14-8185-2014, https://doi.org/10.5194/acp-14-8185-2014, 2014
J. Browse, K. S. Carslaw, G. W. Mann, C. E. Birch, S. R. Arnold, and C. Leck
Atmos. Chem. Phys., 14, 7543–7557, https://doi.org/10.5194/acp-14-7543-2014, https://doi.org/10.5194/acp-14-7543-2014, 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
N. Rastak, S. Silvergren, P. Zieger, U. Wideqvist, J. Ström, B. Svenningsson, M. Maturilli, M. Tesche, A. M. L. Ekman, P. Tunved, and I. Riipinen
Atmos. Chem. Phys., 14, 7445–7460, https://doi.org/10.5194/acp-14-7445-2014, https://doi.org/10.5194/acp-14-7445-2014, 2014
B. Sierau, R. Y.-W. Chang, C. Leck, J. Paatero, and U. Lohmann
Atmos. Chem. Phys., 14, 7409–7430, https://doi.org/10.5194/acp-14-7409-2014, https://doi.org/10.5194/acp-14-7409-2014, 2014
H. Portin, A. Leskinen, L. Hao, A. Kortelainen, P. Miettinen, A. Jaatinen, A. Laaksonen, K. E. J. Lehtinen, S. Romakkaniemi, and M. Komppula
Atmos. Chem. Phys., 14, 6021–6034, https://doi.org/10.5194/acp-14-6021-2014, https://doi.org/10.5194/acp-14-6021-2014, 2014
S. Romakkaniemi, A. Jaatinen, A. Laaksonen, A. Nenes, and T. Raatikainen
Atmos. Meas. Tech., 7, 1377–1384, https://doi.org/10.5194/amt-7-1377-2014, https://doi.org/10.5194/amt-7-1377-2014, 2014
G. W. Mann, K. S. Carslaw, C. L. Reddington, K. J. Pringle, M. Schulz, A. Asmi, D. V. Spracklen, D. A. Ridley, M. T. Woodhouse, L. A. Lee, K. Zhang, S. J. Ghan, R. C. Easter, X. Liu, P. Stier, Y. H. Lee, P. J. Adams, H. Tost, J. Lelieveld, S. E. Bauer, K. Tsigaridis, T. P. C. van Noije, A. Strunk, E. Vignati, N. Bellouin, M. Dalvi, C. E. Johnson, T. Bergman, H. Kokkola, K. von Salzen, F. Yu, G. Luo, A. Petzold, J. Heintzenberg, A. Clarke, J. A. Ogren, J. Gras, U. Baltensperger, U. Kaminski, S. G. Jennings, C. D. O'Dowd, R. M. Harrison, D. C. S. Beddows, M. Kulmala, Y. Viisanen, V. Ulevicius, N. Mihalopoulos, V. Zdimal, M. Fiebig, H.-C. Hansson, E. Swietlicki, and J. S. Henzing
Atmos. Chem. Phys., 14, 4679–4713, https://doi.org/10.5194/acp-14-4679-2014, https://doi.org/10.5194/acp-14-4679-2014, 2014
M. Kuebbeler, U. Lohmann, J. Hendricks, and B. Kärcher
Atmos. Chem. Phys., 14, 3027–3046, https://doi.org/10.5194/acp-14-3027-2014, https://doi.org/10.5194/acp-14-3027-2014, 2014
C. Wesslén, M. Tjernström, D. H. Bromwich, G. de Boer, A. M. L. Ekman, L.-S. Bai, and S.-H. Wang
Atmos. Chem. Phys., 14, 2605–2624, https://doi.org/10.5194/acp-14-2605-2014, https://doi.org/10.5194/acp-14-2605-2014, 2014
J. C. Corbin, B. Sierau, M. Gysel, M. Laborde, A. Keller, J. Kim, A. Petzold, T. B. Onasch, U. Lohmann, and A. A. Mensah
Atmos. Chem. Phys., 14, 2591–2603, https://doi.org/10.5194/acp-14-2591-2014, https://doi.org/10.5194/acp-14-2591-2014, 2014
C. Jiao, M. G. Flanner, Y. Balkanski, S. E. Bauer, N. Bellouin, T. K. Berntsen, H. Bian, K. S. Carslaw, M. Chin, N. De Luca, T. Diehl, S. J. Ghan, T. Iversen, A. Kirkevåg, D. Koch, X. Liu, G. W. Mann, J. E. Penner, G. Pitari, M. Schulz, Ø. Seland, R. B. Skeie, S. D. Steenrod, P. Stier, T. Takemura, K. Tsigaridis, T. van Noije, Y. Yun, and K. Zhang
Atmos. Chem. Phys., 14, 2399–2417, https://doi.org/10.5194/acp-14-2399-2014, https://doi.org/10.5194/acp-14-2399-2014, 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
H. Kokkola, P. Yli-Pirilä, M. Vesterinen, H. Korhonen, H. Keskinen, S. Romakkaniemi, L. Hao, A. Kortelainen, J. Joutsensaari, D. R. Worsnop, A. Virtanen, and K. E. J. Lehtinen
Atmos. Chem. Phys., 14, 1689–1700, https://doi.org/10.5194/acp-14-1689-2014, https://doi.org/10.5194/acp-14-1689-2014, 2014
J. Bialek, M. Dall Osto, P. Vaattovaara, S. Decesari, J. Ovadnevaite, A. Laaksonen, and C. O'Dowd
Atmos. Chem. Phys., 14, 1557–1570, https://doi.org/10.5194/acp-14-1557-2014, https://doi.org/10.5194/acp-14-1557-2014, 2014
T. Korhola, H. Kokkola, H. Korhonen, A.-I. Partanen, A. Laaksonen, K. E. J. Lehtinen, and S. Romakkaniemi
Geosci. Model Dev., 7, 161–174, https://doi.org/10.5194/gmd-7-161-2014, https://doi.org/10.5194/gmd-7-161-2014, 2014
C. E. Scott, A. Rap, D. V. Spracklen, P. M. Forster, K. S. Carslaw, G. W. Mann, K. J. Pringle, N. Kivekäs, M. Kulmala, H. Lihavainen, and P. Tunved
Atmos. Chem. Phys., 14, 447–470, https://doi.org/10.5194/acp-14-447-2014, https://doi.org/10.5194/acp-14-447-2014, 2014
A. Baklanov, K. Schlünzen, P. Suppan, J. Baldasano, D. Brunner, S. Aksoyoglu, G. Carmichael, J. Douros, J. Flemming, R. Forkel, S. Galmarini, M. Gauss, G. Grell, M. Hirtl, S. Joffre, O. Jorba, E. Kaas, M. Kaasik, G. Kallos, X. Kong, U. Korsholm, A. Kurganskiy, J. Kushta, U. Lohmann, A. Mahura, A. Manders-Groot, A. Maurizi, N. Moussiopoulos, S. T. Rao, N. Savage, C. Seigneur, R. S. Sokhi, E. Solazzo, S. Solomos, B. Sørensen, G. Tsegas, E. Vignati, B. Vogel, and Y. Zhang
Atmos. Chem. Phys., 14, 317–398, https://doi.org/10.5194/acp-14-317-2014, https://doi.org/10.5194/acp-14-317-2014, 2014
A. Lipponen, V. Kolehmainen, S. Romakkaniemi, and H. Kokkola
Geosci. Model Dev., 6, 2087–2098, https://doi.org/10.5194/gmd-6-2087-2013, https://doi.org/10.5194/gmd-6-2087-2013, 2013
R. G. Stevens and J. R. Pierce
Atmos. Chem. Phys., 13, 12117–12133, https://doi.org/10.5194/acp-13-12117-2013, https://doi.org/10.5194/acp-13-12117-2013, 2013
A. I. Partanen, A. Laakso, A. Schmidt, H. Kokkola, T. Kuokkanen, J.-P. Pietikäinen, V.-M. Kerminen, K. E. J. Lehtinen, L. Laakso, and H. Korhonen
Atmos. Chem. Phys., 13, 12059–12071, https://doi.org/10.5194/acp-13-12059-2013, https://doi.org/10.5194/acp-13-12059-2013, 2013
J. Henneberger, J. P. Fugal, O. Stetzer, and U. Lohmann
Atmos. Meas. Tech., 6, 2975–2987, https://doi.org/10.5194/amt-6-2975-2013, https://doi.org/10.5194/amt-6-2975-2013, 2013
G. S. Stuart, R. G. Stevens, A.-I. Partanen, A. K. L. Jenkins, H. Korhonen, P. M. Forster, D. V. Spracklen, and J. R. Pierce
Atmos. Chem. Phys., 13, 10385–10396, https://doi.org/10.5194/acp-13-10385-2013, https://doi.org/10.5194/acp-13-10385-2013, 2013
L. A. Ladino Moreno, O. Stetzer, and U. Lohmann
Atmos. Chem. Phys., 13, 9745–9769, https://doi.org/10.5194/acp-13-9745-2013, https://doi.org/10.5194/acp-13-9745-2013, 2013
Z. A. Kanji, A. Welti, C. Chou, O. Stetzer, and U. Lohmann
Atmos. Chem. Phys., 13, 9097–9118, https://doi.org/10.5194/acp-13-9097-2013, https://doi.org/10.5194/acp-13-9097-2013, 2013
L. A. Lee, K. J. Pringle, C. L. Reddington, G. W. Mann, P. Stier, D. V. Spracklen, J. R. Pierce, and K. S. Carslaw
Atmos. Chem. Phys., 13, 8879–8914, https://doi.org/10.5194/acp-13-8879-2013, https://doi.org/10.5194/acp-13-8879-2013, 2013
J. Tonttila, P. Räisänen, and H. Järvinen
Atmos. Chem. Phys., 13, 7551–7565, https://doi.org/10.5194/acp-13-7551-2013, https://doi.org/10.5194/acp-13-7551-2013, 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
H. Keskinen, A. Virtanen, J. Joutsensaari, G. Tsagkogeorgas, J. Duplissy, S. Schobesberger, M. Gysel, F. Riccobono, J. G. Slowik, F. Bianchi, T. Yli-Juuti, K. Lehtipalo, L. Rondo, M. Breitenlechner, A. Kupc, J. Almeida, A. Amorim, E. M. Dunne, A. J. Downard, S. Ehrhart, A. Franchin, M.K. Kajos, J. Kirkby, A. Kürten, T. Nieminen, V. Makhmutov, S. Mathot, P. Miettinen, A. Onnela, T. Petäjä, A. Praplan, F. D. Santos, S. Schallhart, M. Sipilä, Y. Stozhkov, A. Tomé, P. Vaattovaara, D. Wimmer, A. Prevot, J. Dommen, N. M. Donahue, R.C. Flagan, E. Weingartner, Y. Viisanen, I. Riipinen, A. Hansel, J. Curtius, M. Kulmala, D. R. Worsnop, U. Baltensperger, H. Wex, F. Stratmann, and A. Laaksonen
Atmos. Chem. Phys., 13, 5587–5600, https://doi.org/10.5194/acp-13-5587-2013, https://doi.org/10.5194/acp-13-5587-2013, 2013
M. Bentsen, I. Bethke, J. B. Debernard, T. Iversen, A. Kirkevåg, Ø. Seland, H. Drange, C. Roelandt, I. A. Seierstad, C. Hoose, and J. E. Kristjánsson
Geosci. Model Dev., 6, 687–720, https://doi.org/10.5194/gmd-6-687-2013, https://doi.org/10.5194/gmd-6-687-2013, 2013
S. Lance, T. Raatikainen, T. B. Onasch, D. R. Worsnop, X.-Y. Yu, M. L. Alexander, M. R. Stolzenburg, P. H. McMurry, J. N. Smith, and A. Nenes
Atmos. Chem. Phys., 13, 5049–5062, https://doi.org/10.5194/acp-13-5049-2013, https://doi.org/10.5194/acp-13-5049-2013, 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
J. Zábori, R. Krejci, J. Ström, P. Vaattovaara, A. M. L. Ekman, M. E. Salter, E. M. Mårtensson, and E. D. Nilsson
Atmos. Chem. Phys., 13, 4783–4799, https://doi.org/10.5194/acp-13-4783-2013, https://doi.org/10.5194/acp-13-4783-2013, 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
N. Bellouin, G. W. Mann, M. T. Woodhouse, C. Johnson, K. S. Carslaw, and M. Dalvi
Atmos. Chem. Phys., 13, 3027–3044, https://doi.org/10.5194/acp-13-3027-2013, https://doi.org/10.5194/acp-13-3027-2013, 2013
M. T. Woodhouse, G. W. Mann, K. S. Carslaw, and O. Boucher
Atmos. Chem. Phys., 13, 2723–2733, https://doi.org/10.5194/acp-13-2723-2013, https://doi.org/10.5194/acp-13-2723-2013, 2013
A. Kirkevåg, T. Iversen, Ø. Seland, C. Hoose, J. E. Kristjánsson, H. Struthers, A. M. L. Ekman, S. Ghan, J. Griesfeller, E. D. Nilsson, and M. Schulz
Geosci. Model Dev., 6, 207–244, https://doi.org/10.5194/gmd-6-207-2013, https://doi.org/10.5194/gmd-6-207-2013, 2013
C. Chou, Z. A. Kanji, O. Stetzer, T. Tritscher, R. Chirico, M. F. Heringa, E. Weingartner, A. S. H. Prévôt, U. Baltensperger, and U. Lohmann
Atmos. Chem. Phys., 13, 761–772, https://doi.org/10.5194/acp-13-761-2013, https://doi.org/10.5194/acp-13-761-2013, 2013
V.-M. Kerminen, M. Paramonov, T. Anttila, I. Riipinen, C. Fountoukis, H. Korhonen, E. Asmi, L. Laakso, H. Lihavainen, E. Swietlicki, B. Svenningsson, A. Asmi, S. N. Pandis, M. Kulmala, and T. Petäjä
Atmos. Chem. Phys., 12, 12037–12059, https://doi.org/10.5194/acp-12-12037-2012, https://doi.org/10.5194/acp-12-12037-2012, 2012
E. M. Dunne, L. A. Lee, C. L. Reddington, and K. S. Carslaw
Atmos. Chem. Phys., 12, 11573–11587, https://doi.org/10.5194/acp-12-11573-2012, https://doi.org/10.5194/acp-12-11573-2012, 2012
Related subject area
Subject: Clouds and Precipitation | Research Activity: Atmospheric Modelling | Altitude Range: Troposphere | Science Focus: Physics (physical properties and processes)
Impacts of cloud microphysics parameterizations on simulated aerosol–cloud interactions for deep convective clouds over Houston
Cold cloud microphysical process rates in a global chemistry–climate model
Precipitation enhancement in stratocumulus clouds through airborne seeding: sensitivity analysis by UCLALES-SALSA
Secondary ice production in summer clouds over the Antarctic coast: an underappreciated process in atmospheric models
Opinion: Cloud-phase climate feedback and the importance of ice-nucleating particles
On the ice-nucleating potential of warm hydrometeors in mixed-phase clouds
The enhancement of droplet collision by electric charges and atmospheric electric fields
Cloud adjustments dominate the overall negative aerosol radiative effects of biomass burning aerosols in UKESM1 climate model simulations over the south-eastern Atlantic
Dependence of predictability of precipitation in the northwestern Mediterranean coastal region on the strength of synoptic control
The decomposition of cloud–aerosol forcing in the UK Earth System Model (UKESM1)
Sensitivity of warm clouds to large particles in measured marine aerosol size distributions – a theoretical study
Hectometric-scale simulations of a Mediterranean heavy-precipitation event during the Hydrological cycle in the Mediterranean Experiment (HyMeX) first Special Observation Period (SOP1)
Urbanization-induced land and aerosol impacts on sea-breeze circulation and convective precipitation
Shallow Cumulus Cloud Feedback in Large Eddy Simulations – Bridging the Gap to Storm Resolving Models
Snow-induced buffering in aerosol–cloud interactions
Environmental sensitivities of shallow-cumulus dilution – Part 1: Selected thermodynamic conditions
Employing airborne radiation and cloud microphysics observations to improve cloud representation in ICON at kilometer-scale resolution in the Arctic
Cloud droplet diffusional growth in homogeneous isotropic turbulence: bin microphysics versus Lagrangian superdroplet simulations
An idealized model sensitivity study on Dead Sea desertification with a focus on the impact on convection
Modelling mixed-phase clouds with the large-eddy model UCLALES–SALSA
Yuwei Zhang, Jiwen Fan, Zhanqing Li, and Daniel Rosenfeld
Atmos. Chem. Phys., 21, 2363–2381, https://doi.org/10.5194/acp-21-2363-2021, https://doi.org/10.5194/acp-21-2363-2021, 2021
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Impacts of anthropogenic aerosols on deep convective clouds (DCCs) and precipitation are examined using both the Morrison bulk and spectral bin microphysics (SBM) schemes. With the SBM scheme, anthropogenic aerosols notably invigorate convective intensity and precipitation, causing better agreement between the simulated DCCs and observations; this effect is absent with the Morrison scheme, mainly due to limitations of the saturation adjustment approach for droplet condensation and evaporation.
Sara Bacer, Sylvia C. Sullivan, Odran Sourdeval, Holger Tost, Jos Lelieveld, and Andrea Pozzer
Atmos. Chem. Phys., 21, 1485–1505, https://doi.org/10.5194/acp-21-1485-2021, https://doi.org/10.5194/acp-21-1485-2021, 2021
Short summary
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We investigate the relative importance of the rates of both microphysical processes and unphysical correction terms that act as sources or sinks of ice crystals in cold clouds. By means of numerical simulations performed with a global chemistry–climate model, we assess the relevance of these rates at global and regional scales. This estimation is of fundamental importance to assign priority to the development of microphysics parameterizations and compare model output with observations.
Juha Tonttila, Ali Afzalifar, Harri Kokkola, Tomi Raatikainen, Hannele Korhonen, and Sami Romakkaniemi
Atmos. Chem. Phys., 21, 1035–1048, https://doi.org/10.5194/acp-21-1035-2021, https://doi.org/10.5194/acp-21-1035-2021, 2021
Short summary
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The focus of this study is on rain enhancement by deliberate injection of small particles into clouds (
cloud seeding). The particles, usually released from an aircraft, are expected to enhance cloud droplet growth, but its practical feasibility is somewhat uncertain. To improve upon this, we simulate the seeding effects with a numerical model. The model reproduces the main features seen in field observations, with a strong sensitivity to the total mass of the injected particle material.
Georgia Sotiropoulou, Étienne Vignon, Gillian Young, Hugh Morrison, Sebastian J. O'Shea, Thomas Lachlan-Cope, Alexis Berne, and Athanasios Nenes
Atmos. Chem. Phys., 21, 755–771, https://doi.org/10.5194/acp-21-755-2021, https://doi.org/10.5194/acp-21-755-2021, 2021
Short summary
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Summer clouds have a significant impact on the radiation budget of the Antarctic surface and thus on ice-shelf melting. However, these are poorly represented in climate models due to errors in their microphysical structure, including the number of ice crystals that they contain. We show that breakup from ice particle collisions can substantially magnify the ice crystal number concentration with significant implications for surface radiation. This process is currently missing in climate models.
Benjamin J. Murray, Kenneth S. Carslaw, and Paul R. Field
Atmos. Chem. Phys., 21, 665–679, https://doi.org/10.5194/acp-21-665-2021, https://doi.org/10.5194/acp-21-665-2021, 2021
Short summary
Short summary
The balance between the amounts of ice and supercooled water in clouds over the world's oceans strongly influences how much these clouds can dampen or amplify global warming. Aerosol particles which catalyse ice formation can dramatically reduce the amount of supercooled water in clouds; hence we argue that we need a concerted effort to improve our understanding of these ice-nucleating particles if we are to improve our predictions of climate change.
Michael Krayer, Agathe Chouippe, Markus Uhlmann, Jan Dušek, and Thomas Leisner
Atmos. Chem. Phys., 21, 561–575, https://doi.org/10.5194/acp-21-561-2021, https://doi.org/10.5194/acp-21-561-2021, 2021
Short summary
Short summary
We address the phenomenon of ice enhancement in the vicinity of warm hydrometeors using highly accurate flow simulation techniques. It is found that the transiently supersaturated zones induced by the hydrometeor's wake are by far larger than what has been previously estimated. The ice enhancement is quantified on the micro- and macroscale, and its relevance is discussed. The results provided may contribute to a (currently unavailable) parametrization of the phenomenon.
Shian Guo and Huiwen Xue
Atmos. Chem. Phys., 21, 69–85, https://doi.org/10.5194/acp-21-69-2021, https://doi.org/10.5194/acp-21-69-2021, 2021
Short summary
Short summary
Observations in previous studies show that cloud droplets carry electric charges. We are curious about whether the electric interaction enhances the collision of cloud droplets. The effect of the electric charge and atmospheric electric field on the raindrop-formation process is studied numerically. Results indicate that a cloud with a small droplet size is more sensitive to an electric charge and field, which could significantly trigger droplet collision and accelerate raindrop formation.
Haochi Che, Philip Stier, Hamish Gordon, Duncan Watson-Parris, and Lucia Deaconu
Atmos. Chem. Phys., 21, 17–33, https://doi.org/10.5194/acp-21-17-2021, https://doi.org/10.5194/acp-21-17-2021, 2021
Short summary
Short summary
The south-eastern Atlantic is semi-permanently covered by some of the largest stratocumulus clouds and is influenced by one-third of the biomass burning emissions from African fires. A UKEMS1 model simulation shows that the absorption effect of biomass burning aerosols is the most significant on clouds and radiation. The dominate cooling and rapid adjustments induced by the radiative effects of biomass burning aerosols result in an overall cooling in the south-eastern Atlantic.
Christian Keil, Lucie Chabert, Olivier Nuissier, and Laure Raynaud
Atmos. Chem. Phys., 20, 15851–15865, https://doi.org/10.5194/acp-20-15851-2020, https://doi.org/10.5194/acp-20-15851-2020, 2020
Short summary
Short summary
During strong synoptic control, which dominates the weather on 80 % of the days in the 2-month HyMeX-SOP1 period, the domain-integrated precipitation predictability assessed with the normalized ensemble standard deviation is above average, the wet bias is smaller and the forecast quality is generally better. In contrast, the spatial forecast quality of the most intense precipitation in the afternoon, as quantified with its 95th percentile, is superior during weakly forced synoptic regimes.
Daniel P. Grosvenor and Kenneth S. Carslaw
Atmos. Chem. Phys., 20, 15681–15724, https://doi.org/10.5194/acp-20-15681-2020, https://doi.org/10.5194/acp-20-15681-2020, 2020
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Particles arising from human activity interact with clouds and affect how much of the Sun's energy is reflected away. Lack of understanding about how to represent this in models leads to large uncertainties in climate predictions. We quantify cloud responses to particles in the latest UK Met Office climate model over the North Atlantic Ocean, showing that, in contrast to suggestions elsewhere, increases in cloud coverage and thickness are important over large areas.
Tom Dror, J. Michel Flores, Orit Altaratz, Guy Dagan, Zev Levin, Assaf Vardi, and Ilan Koren
Atmos. Chem. Phys., 20, 15297–15306, https://doi.org/10.5194/acp-20-15297-2020, https://doi.org/10.5194/acp-20-15297-2020, 2020
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We used in situ aerosol measurements over the Atlantic, Caribbean, and Pacific to initialize a cloud model and study the impact of aerosol concentration and sizes on warm clouds. We show that high aerosol concentration increases cloud mass and reduces surface rain when giant particles (diameter > 9 µm) are present. The large aerosols changed the timing and magnitude of internal cloud processes and resulted in an enhanced evaporation below cloud base and dramatically reduced surface rain.
Olivier Nuissier, Fanny Duffourg, Maxime Martinet, Véronique Ducrocq, and Christine Lac
Atmos. Chem. Phys., 20, 14649–14667, https://doi.org/10.5194/acp-20-14649-2020, https://doi.org/10.5194/acp-20-14649-2020, 2020
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This present article demonstrates how numerical simulations with very high horizontal resolution (150 m) can contribute to better understanding the key physical processes (turbulence and microphysics) that lead to Mediterranean heavy precipitation.
Jiwen Fan, Yuwei Zhang, Zhanqing Li, Jiaxi Hu, and Daniel Rosenfeld
Atmos. Chem. Phys., 20, 14163–14182, https://doi.org/10.5194/acp-20-14163-2020, https://doi.org/10.5194/acp-20-14163-2020, 2020
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We investigate the urbanization-induced land and aerosol impacts on convective clouds and precipitation over Houston. We find that Houston urbanization notably enhances storm intensity and precipitation, with the anthropogenic aerosol effect more significant. Urban land effect strengthens sea-breeze circulation, leading to a faster development of warm cloud into mixed-phase cloud and earlier rain. The anthropogenic aerosol effect accelerates the development of storms into deep convection.
Jule Radtke, Thorsten Mauritsen, and Cathy Hohenegger
Atmos. Chem. Phys. Discuss., https://doi.org/10.5194/acp-2020-1160, https://doi.org/10.5194/acp-2020-1160, 2020
Revised manuscript accepted for ACP
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Shallow trade wind clouds are a key source of uncertainty to projections of the Earth's changing climate. We perform high resolution simulations of trade cumulus and investigate how the representation and climate feedback of these clouds depends on the specific grid spacing. We find that the cloud feedback is positive when simulated with kilometer but near zero when simulated with hectometer grid spacing. These findings suggest that storm resolving models may exaggerate the trade cloud feedback.
Takuro Michibata, Kentaroh Suzuki, and Toshihiko Takemura
Atmos. Chem. Phys., 20, 13771–13780, https://doi.org/10.5194/acp-20-13771-2020, https://doi.org/10.5194/acp-20-13771-2020, 2020
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This work reveals that prognostic precipitation significantly reduces the magnitude of aerosol–cloud interactions (ERFaci), mainly due to the collection process associated with snowflakes and underlying cloud droplets. This precipitation-driven buffering effect, which is missing in traditional GCMs, can explain the model–observation discrepancy in ERFaci. These results underscore the necessity for a prognostic precipitation framework in GCMs for more reliable climate simulations.
Sonja Drueke, Daniel J. Kirshbaum, and Pavlos Kollias
Atmos. Chem. Phys., 20, 13217–13239, https://doi.org/10.5194/acp-20-13217-2020, https://doi.org/10.5194/acp-20-13217-2020, 2020
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This numerical study provides insights into selected environmental sensitivities of shallow-cumulus dilution. Among the parameters under consideration, the dilution of the cloud cores is strongly sensitive to continentality and cloud-layer relative humidity and weakly sensitive to subcloud- and cloud-layer depths. The impacts of all four parameters are interpreted using a similarity theory of shallow cumulus and buoyancy-sorting arguments.
Jan Kretzschmar, Johannes Stapf, Daniel Klocke, Manfred Wendisch, and Johannes Quaas
Atmos. Chem. Phys., 20, 13145–13165, https://doi.org/10.5194/acp-20-13145-2020, https://doi.org/10.5194/acp-20-13145-2020, 2020
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This study compares simulations with the ICON model at the kilometer scale to airborne radiation and cloud microphysics observations that have been derived during the ACLOUD aircraft campaign around Svalbard, Norway, in May/June 2017. We find an overestimated surface warming effect of clouds compared to the observations in our setup. This bias was reduced by considering subgrid-scale vertical motion in the activation of cloud condensation nuclei in the two-moment microphysical scheme used.
Wojciech W. Grabowski and Lois Thomas
Atmos. Chem. Phys. Discuss., https://doi.org/10.5194/acp-2020-1106, https://doi.org/10.5194/acp-2020-1106, 2020
Revised manuscript accepted for ACP
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This paper presents a modeling study that investigates the impact of cloud turbulence on the diffusional growth of cloud droplets and compares modeling results to analytic solutions published in the past. The focus is on comparing the two microphysics modeling methodologies, the Eulerian bin microphysics and Lagrangian particle-based microphysics, and exposing their limitations.
Samiro Khodayar and Johannes Hoerner
Atmos. Chem. Phys., 20, 12011–12031, https://doi.org/10.5194/acp-20-12011-2020, https://doi.org/10.5194/acp-20-12011-2020, 2020
Jaakko Ahola, Hannele Korhonen, Juha Tonttila, Sami Romakkaniemi, Harri Kokkola, and Tomi Raatikainen
Atmos. Chem. Phys., 20, 11639–11654, https://doi.org/10.5194/acp-20-11639-2020, https://doi.org/10.5194/acp-20-11639-2020, 2020
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