Articles | Volume 20, issue 4
https://doi.org/10.5194/acp-20-2341-2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/acp-20-2341-2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| Highlight paper
| 
27 Feb 2020
Research article | Highlight paper |
| 27 Feb 2020
| 27 Feb 2020
Ultra-clean and smoky marine boundary layers frequently occur in the same season over the southeast Atlantic
Sam Pennypacker
CORRESPONDING AUTHOR
Department of Atmospheric Sciences, University of Washington, Seattle,
WA, USA
Michael Diamond
Department of Atmospheric Sciences, University of Washington, Seattle,
WA, USA
Robert Wood
Department of Atmospheric Sciences, University of Washington, Seattle,
WA, USA
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Atmos. Chem. Phys. Discuss., https://doi.org/10.5194/acp-2016-289, https://doi.org/10.5194/acp-2016-289, 2016
Revised manuscript has not been submitted
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We examine aerosol-cloud interactions detected in springtime cloud statistics over the Southern Great Plains of the United States in the context of cloud phase, measurement uncertainty and regional meteorology. Satellite retrievals of cloud properties are collocated with surface aerosol measurements over five years. The goal is to frame and motivate further work in what could cause deviations from the traditional theory of aerosol-cloud interactions over a given region.
Je-Yun Chun, Robert Wood, Peter N. Blossey, and Sarah J. Doherty
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Chris J. Wright, Joel A. Thornton, Lyatt Jaeglé, Yang Cao, Yannian Zhu, Jihu Liu, Randall Jones II, Robert Holzworth, Daniel Rosenfeld, Robert Wood, Peter Blossey, and Daehyun Kim
Atmos. Chem. Phys., 25, 2937–2946, https://doi.org/10.5194/acp-25-2937-2025, https://doi.org/10.5194/acp-25-2937-2025, 2025
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Aerosol particles influence clouds, which exert a large forcing on solar radiation and freshwater. To better understand the mechanisms by which aerosol influences thunderstorms, we look at the two busiest shipping lanes in the world, where recent regulations have reduced sulfur emissions by nearly an order of magnitude. We find that the reduction in emissions has been accompanied by a dramatic decrease in both lightning and the number of droplets in clouds over the shipping lanes.
Philip J. Rasch, Haruki Hirasawa, Mingxuan Wu, Sarah J. Doherty, Robert Wood, Hailong Wang, Andy Jones, James Haywood, and Hansi Singh
Geosci. Model Dev., 17, 7963–7994, https://doi.org/10.5194/gmd-17-7963-2024, https://doi.org/10.5194/gmd-17-7963-2024, 2024
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Lucas A. McMichael, Michael J. Schmidt, Robert Wood, Peter N. Blossey, and Lekha Patel
Geosci. Model Dev., 17, 7867–7888, https://doi.org/10.5194/gmd-17-7867-2024, https://doi.org/10.5194/gmd-17-7867-2024, 2024
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Ehsan Erfani, Robert Wood, Peter Blossey, Sarah J. Doherty, and Ryan Eastman
EGUsphere, https://doi.org/10.5194/egusphere-2024-3232, https://doi.org/10.5194/egusphere-2024-3232, 2024
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Ryan Eastman, Isabel L. McCoy, Hauke Schulz, and Robert Wood
Atmos. Chem. Phys., 24, 6613–6634, https://doi.org/10.5194/acp-24-6613-2024, https://doi.org/10.5194/acp-24-6613-2024, 2024
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Cloud types are determined using machine learning image classifiers applied to satellite imagery for 1 year in the North Atlantic. This survey of these cloud types shows that the climate impact of a cloud scene is, in part, a function of cloud type. Each type displays a different mix of thick and thin cloud cover, with the fraction of thin cloud cover having the strongest impact on the clouds' radiative effect. Future studies must account for differing properties and processes among cloud types.
Alejandro Baró Pérez, Michael S. Diamond, Frida A.-M. Bender, Abhay Devasthale, Matthias Schwarz, Julien Savre, Juha Tonttila, Harri Kokkola, Hyunho Lee, David Painemal, and Annica M. L. Ekman
Atmos. Chem. Phys., 24, 4591–4610, https://doi.org/10.5194/acp-24-4591-2024, https://doi.org/10.5194/acp-24-4591-2024, 2024
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We use a numerical model to study interactions between humid light-absorbing aerosol plumes, clouds, and radiation over the southeast Atlantic. We find that the warming produced by the aerosols reduces cloud cover, especially in highly polluted situations. Aerosol impacts on drizzle play a minor role. However, aerosol effects on cloud reflectivity and moisture-induced changes in cloud cover dominate the climatic response and lead to an overall cooling by the biomass burning plumes.
Calvin Howes, Pablo E. Saide, Hugh Coe, Amie Dobracki, Steffen Freitag, Jim M. Haywood, Steven G. Howell, Siddhant Gupta, Janek Uin, Mary Kacarab, Chongai Kuang, L. Ruby Leung, Athanasios Nenes, Greg M. McFarquhar, James Podolske, Jens Redemann, Arthur J. Sedlacek, Kenneth L. Thornhill, Jenny P. S. Wong, Robert Wood, Huihui Wu, Yang Zhang, Jianhao Zhang, and Paquita Zuidema
Atmos. Chem. Phys., 23, 13911–13940, https://doi.org/10.5194/acp-23-13911-2023, https://doi.org/10.5194/acp-23-13911-2023, 2023
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To better understand smoke properties and its interactions with clouds, we compare the WRF-CAM5 model with observations from ORACLES, CLARIFY, and LASIC field campaigns in the southeastern Atlantic in August 2017. The model transports and mixes smoke well but does not fully capture some important processes. These include smoke chemical and physical aging over 4–12 days, smoke removal by rain, sulfate particle formation, aerosol activation into cloud droplets, and boundary layer turbulence.
Michael S. Diamond
Atmos. Chem. Phys., 23, 8259–8269, https://doi.org/10.5194/acp-23-8259-2023, https://doi.org/10.5194/acp-23-8259-2023, 2023
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Fuel sulfur regulations were implemented for ships in 2020 to improve air quality but may also accelerate global warming. We use spatial statistics and satellite retrievals to detect changes in the size of cloud droplets and find evidence for a resulting decrease in cloud brightness within a major shipping corridor after the sulfur limits went into effect. Our results confirm both that the regulations are being followed and that they are having a warming influence via their effect on clouds.
Amie Dobracki, Paquita Zuidema, Steven G. Howell, Pablo Saide, Steffen Freitag, Allison C. Aiken, Sharon P. Burton, Arthur J. Sedlacek III, Jens Redemann, and Robert Wood
Atmos. Chem. Phys., 23, 4775–4799, https://doi.org/10.5194/acp-23-4775-2023, https://doi.org/10.5194/acp-23-4775-2023, 2023
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Southern Africa produces approximately one-third of the world’s carbon from fires. The thick smoke layer can flow westward, interacting with the southeastern Atlantic cloud deck. The net radiative impact can alter regional circulation patterns, impacting rainfall over Africa. We find that the smoke is highly absorbing of sunlight, mostly because it contains more black carbon than smoke over the Northern Hemisphere.
Ian Chang, Lan Gao, Connor J. Flynn, Yohei Shinozuka, Sarah J. Doherty, Michael S. Diamond, Karla M. Longo, Gonzalo A. Ferrada, Gregory R. Carmichael, Patricia Castellanos, Arlindo M. da Silva, Pablo E. Saide, Calvin Howes, Zhixin Xue, Marc Mallet, Ravi Govindaraju, Qiaoqiao Wang, Yafang Cheng, Yan Feng, Sharon P. Burton, Richard A. Ferrare, Samuel E. LeBlanc, Meloë S. Kacenelenbogen, Kristina Pistone, Michal Segal-Rozenhaimer, Kerry G. Meyer, Ju-Mee Ryoo, Leonhard Pfister, Adeyemi A. Adebiyi, Robert Wood, Paquita Zuidema, Sundar A. Christopher, and Jens Redemann
Atmos. Chem. Phys., 23, 4283–4309, https://doi.org/10.5194/acp-23-4283-2023, https://doi.org/10.5194/acp-23-4283-2023, 2023
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Abundant aerosols are present above low-level liquid clouds over the southeastern Atlantic during late austral spring. The model simulation differences in the proportion of aerosol residing in the planetary boundary layer and in the free troposphere can greatly affect the regional aerosol radiative effects. This study examines the aerosol loading and fractional aerosol loading in the free troposphere among various models and evaluates them against measurements from the NASA ORACLES campaign.
Francesca Gallo, Janek Uin, Kevin J. Sanchez, Richard H. Moore, Jian Wang, Robert Wood, Fan Mei, Connor Flynn, Stephen Springston, Eduardo B. Azevedo, Chongai Kuang, and Allison C. Aiken
Atmos. Chem. Phys., 23, 4221–4246, https://doi.org/10.5194/acp-23-4221-2023, https://doi.org/10.5194/acp-23-4221-2023, 2023
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Zhenquan Wang, Jian Yuan, Robert Wood, Yifan Chen, and Tiancheng Tong
Atmos. Chem. Phys., 23, 3247–3266, https://doi.org/10.5194/acp-23-3247-2023, https://doi.org/10.5194/acp-23-3247-2023, 2023
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This study develops a novel profile-based algorithm based on the ERA5 to estimate the inversion strength in the planetary boundary layer better than the previous inversion index, which is a key low-cloud-controlling factor. This improved measure is more effective at representing the meteorological influence on low-cloud variations. It can better constrain the meteorological influence on low clouds to better isolate cloud responses to aerosols or to estimate low cloud feedbacks in climate models.
Je-Yun Chun, Robert Wood, Peter Blossey, and Sarah J. Doherty
Atmos. Chem. Phys., 23, 1345–1368, https://doi.org/10.5194/acp-23-1345-2023, https://doi.org/10.5194/acp-23-1345-2023, 2023
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We investigate the impact of injected aerosol on subtropical low marine clouds under a variety of meteorological conditions using high-resolution model simulations. This study illustrates processes perturbed by aerosol injections and their impact on cloud properties (e.g., cloud number concentration, thickness, and cover). We show that those responses are highly sensitive to background meteorological conditions, such as precipitation, and background cloud properties.
Ju-Mee Ryoo, Leonhard Pfister, Rei Ueyama, Paquita Zuidema, Robert Wood, Ian Chang, and Jens Redemann
Atmos. Chem. Phys., 22, 14209–14241, https://doi.org/10.5194/acp-22-14209-2022, https://doi.org/10.5194/acp-22-14209-2022, 2022
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The variability in the meteorological fields during each deployment is highly modulated at a daily to synoptic timescale. This paper, along with part 1, the climatological overview paper, provides a meteorological context for interpreting the airborne measurements gathered during the three ORACLES deployments. This study supports related studies focusing on the detailed investigation of the processes controlling stratocumulus decks, aerosol lifting, transport, and their interactions.
Paul A. Barrett, Steven J. Abel, Hugh Coe, Ian Crawford, Amie Dobracki, James Haywood, Steve Howell, Anthony Jones, Justin Langridge, Greg M. McFarquhar, Graeme J. Nott, Hannah Price, Jens Redemann, Yohei Shinozuka, Kate Szpek, Jonathan W. Taylor, Robert Wood, Huihui Wu, Paquita Zuidema, Stéphane Bauguitte, Ryan Bennett, Keith Bower, Hong Chen, Sabrina Cochrane, Michael Cotterell, Nicholas Davies, David Delene, Connor Flynn, Andrew Freedman, Steffen Freitag, Siddhant Gupta, David Noone, Timothy B. Onasch, James Podolske, Michael R. Poellot, Sebastian Schmidt, Stephen Springston, Arthur J. Sedlacek III, Jamie Trembath, Alan Vance, Maria A. Zawadowicz, and Jianhao Zhang
Atmos. Meas. Tech., 15, 6329–6371, https://doi.org/10.5194/amt-15-6329-2022, https://doi.org/10.5194/amt-15-6329-2022, 2022
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To better understand weather and climate, it is vital to go into the field and collect observations. Often measurements take place in isolation, but here we compared data from two aircraft and one ground-based site. This was done in order to understand how well measurements made on one platform compared to those made on another. Whilst this is easy to do in a controlled laboratory setting, it is more challenging in the real world, and so these comparisons are as valuable as they are rare.
Michael S. Diamond, Pablo E. Saide, Paquita Zuidema, Andrew S. Ackerman, Sarah J. Doherty, Ann M. Fridlind, Hamish Gordon, Calvin Howes, Jan Kazil, Takanobu Yamaguchi, Jianhao Zhang, Graham Feingold, and Robert Wood
Atmos. Chem. Phys., 22, 12113–12151, https://doi.org/10.5194/acp-22-12113-2022, https://doi.org/10.5194/acp-22-12113-2022, 2022
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Smoke from southern Africa blankets the southeast Atlantic from June-October, overlying a major transition region between overcast and scattered clouds. The smoke affects Earth's radiation budget by absorbing sunlight and changing cloud properties. We investigate these effects in regional climate and large eddy simulation models based on international field campaigns. We find that large-scale circulation changes more strongly affect cloud transitions than smoke microphysical effects in our case.
Jessica Danker, Odran Sourdeval, Isabel L. McCoy, Robert Wood, and Anna Possner
Atmos. Chem. Phys., 22, 10247–10265, https://doi.org/10.5194/acp-22-10247-2022, https://doi.org/10.5194/acp-22-10247-2022, 2022
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Using spaceborne lidar-radar retrievals, we show that seasonal changes in cloud phase outweigh changes in cloud-phase statistics across cloud morphologies at given cloud-top temperatures. These results show that cloud morphology does not seem to pose a primary constraint on cloud-phase statistics in the Southern Ocean. Meanwhile, larger changes in in-cloud albedo across cloud morphologies are observed in supercooled liquid rather than mixed-phase stratocumuli.
Matthew W. Christensen, Andrew Gettelman, Jan Cermak, Guy Dagan, Michael Diamond, Alyson Douglas, Graham Feingold, Franziska Glassmeier, Tom Goren, Daniel P. Grosvenor, Edward Gryspeerdt, Ralph Kahn, Zhanqing Li, Po-Lun Ma, Florent Malavelle, Isabel L. McCoy, Daniel T. McCoy, Greg McFarquhar, Johannes Mülmenstädt, Sandip Pal, Anna Possner, Adam Povey, Johannes Quaas, Daniel Rosenfeld, Anja Schmidt, Roland Schrödner, Armin Sorooshian, Philip Stier, Velle Toll, Duncan Watson-Parris, Robert Wood, Mingxi Yang, and Tianle Yuan
Atmos. Chem. Phys., 22, 641–674, https://doi.org/10.5194/acp-22-641-2022, https://doi.org/10.5194/acp-22-641-2022, 2022
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Trace gases and aerosols (tiny airborne particles) are released from a variety of point sources around the globe. Examples include volcanoes, industrial chimneys, forest fires, and ship stacks. These sources provide opportunistic experiments with which to quantify the role of aerosols in modifying cloud properties. We review the current state of understanding on the influence of aerosol on climate built from the wide range of natural and anthropogenic laboratories investigated in recent decades.
Sarah J. Doherty, Pablo E. Saide, Paquita Zuidema, Yohei Shinozuka, Gonzalo A. Ferrada, Hamish Gordon, Marc Mallet, Kerry Meyer, David Painemal, Steven G. Howell, Steffen Freitag, Amie Dobracki, James R. Podolske, Sharon P. Burton, Richard A. Ferrare, Calvin Howes, Pierre Nabat, Gregory R. Carmichael, Arlindo da Silva, Kristina Pistone, Ian Chang, Lan Gao, Robert Wood, and Jens Redemann
Atmos. Chem. Phys., 22, 1–46, https://doi.org/10.5194/acp-22-1-2022, https://doi.org/10.5194/acp-22-1-2022, 2022
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Between July and October, biomass burning smoke is advected over the southeastern Atlantic Ocean, leading to climate forcing. Model calculations of forcing by this plume vary significantly in both magnitude and sign. This paper compares aerosol and cloud properties observed during three NASA ORACLES field campaigns to the same in four models. It quantifies modeled biases in properties key to aerosol direct radiative forcing and evaluates how these biases propagate to biases in forcing.
Amie Dobracki, Paquita Zuidema, Steve Howell, Pablo Saide, Steffen Freitag, Allison C. Aiken, Sharon P. Burton, Arthur J. Sedlacek III, Jens Redemann, and Robert Wood
Atmos. Chem. Phys. Discuss., https://doi.org/10.5194/acp-2021-1081, https://doi.org/10.5194/acp-2021-1081, 2022
Preprint withdrawn
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The global maximum of shortwave-absorbing aerosol above cloud occurs above the southeast Atlantic, where the biomass-burning aerosol provides a distinct aerosol radiative warming of regional climate. The smoke aerosols are unusually highly absorbing of sunlight. This study seeks to understand the cause. We conclude the aerosol is already strongly absorbing at the fire emission source, but that chemical aging, through encouraging a net loss of organic aerosol, also contributes.
Ju-Mee Ryoo, Leonhard Pfister, Rei Ueyama, Paquita Zuidema, Robert Wood, Ian Chang, and Jens Redemann
Atmos. Chem. Phys., 21, 16689–16707, https://doi.org/10.5194/acp-21-16689-2021, https://doi.org/10.5194/acp-21-16689-2021, 2021
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Part 1 of the meteorological overview paper highlights the anomalous meteorological characteristics during the ORACLES deployment compared to the climatological mean at monthly timescales. The upper-level wave disturbance and the associated anomalous circulation explain the weakening of AEJ-S through the reduction of the strength of the heat low over the land during August 2017. This may also help explain the anomalously low aerosol optical depth observed in the August 2017 ORACLES deployment.
Rachel Atlas, Johannes Mohrmann, Joseph Finlon, Jeremy Lu, Ian Hsiao, Robert Wood, and Minghui Diao
Atmos. Meas. Tech., 14, 7079–7101, https://doi.org/10.5194/amt-14-7079-2021, https://doi.org/10.5194/amt-14-7079-2021, 2021
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Many clouds with temperatures between 0 °C and −40 °C contain both liquid and ice particles, and the ratio of liquid to ice particles influences how the clouds interact with radiation and moderate Earth's climate. We use a machine learning method called random forest to classify images of individual cloud particles as either liquid or ice. We apply our algorithm to images captured by aircraft within clouds overlying the Southern Ocean, and we find that it outperforms two existing algorithms.
Robert Wood
Atmos. Chem. Phys., 21, 14507–14533, https://doi.org/10.5194/acp-21-14507-2021, https://doi.org/10.5194/acp-21-14507-2021, 2021
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A simple model is described to assess the potential for increasing solar reflection by augmenting the aerosol population below marine low clouds, which increases the concentration of cloud droplets. The model is used to predict global cooling from marine cloud brightening climate intervention as a function of the quantity, size, and lifetime of salt particles injected per sprayer, the number of sprayers deployed, the cloud updraft speed, and unperturbed aerosol size distribution.
Yang Wang, Guangjie Zheng, Michael P. Jensen, Daniel A. Knopf, Alexander Laskin, Alyssa A. Matthews, David Mechem, Fan Mei, Ryan Moffet, Arthur J. Sedlacek, John E. Shilling, Stephen Springston, Amy Sullivan, Jason Tomlinson, Daniel Veghte, Rodney Weber, Robert Wood, Maria A. Zawadowicz, and Jian Wang
Atmos. Chem. Phys., 21, 11079–11098, https://doi.org/10.5194/acp-21-11079-2021, https://doi.org/10.5194/acp-21-11079-2021, 2021
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This paper reports the vertical profiles of trace gas and aerosol properties over the eastern North Atlantic, a region of persistent but diverse subtropical marine boundary layer (MBL) clouds. We examined the key processes that drive the cloud condensation nuclei (CCN) population and how it varies with season and synoptic conditions. This study helps improve the model representation of the aerosol processes in the remote MBL, reducing the simulated aerosol indirect effects.
Kristina Pistone, Paquita Zuidema, Robert Wood, Michael Diamond, Arlindo M. da Silva, Gonzalo Ferrada, Pablo E. Saide, Rei Ueyama, Ju-Mee Ryoo, Leonhard Pfister, James Podolske, David Noone, Ryan Bennett, Eric Stith, Gregory Carmichael, Jens Redemann, Connor Flynn, Samuel LeBlanc, Michal Segal-Rozenhaimer, and Yohei Shinozuka
Atmos. Chem. Phys., 21, 9643–9668, https://doi.org/10.5194/acp-21-9643-2021, https://doi.org/10.5194/acp-21-9643-2021, 2021
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Using aircraft-based measurements off the Atlantic coast of Africa, we found the springtime smoke plume was strongly correlated with the amount of water vapor in the atmosphere (more smoke indicated more humidity). We see the same general feature in satellite-assimilated and free-running models. Our analysis suggests this relationship is not caused by the burning but originates due to coincident continental meteorology plus fires. This air is transported over the ocean without further mixing.
Johannes Mohrmann, Robert Wood, Tianle Yuan, Hua Song, Ryan Eastman, and Lazaros Oreopoulos
Atmos. Chem. Phys., 21, 9629–9642, https://doi.org/10.5194/acp-21-9629-2021, https://doi.org/10.5194/acp-21-9629-2021, 2021
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Observations of marine-boundary-layer conditions are composited by cloud type, based on a new classification dataset. It is found that two cloud types, representing regions of clustered and suppressed low-level clouds, occur in very similar large-scale conditions but are distinguished from each other by considering low-level circulation and surface wind fields, validating prior results from modeling.
Maria A. Zawadowicz, Kaitlyn Suski, Jiumeng Liu, Mikhail Pekour, Jerome Fast, Fan Mei, Arthur J. Sedlacek, Stephen Springston, Yang Wang, Rahul A. Zaveri, Robert Wood, Jian Wang, and John E. Shilling
Atmos. Chem. Phys., 21, 7983–8002, https://doi.org/10.5194/acp-21-7983-2021, https://doi.org/10.5194/acp-21-7983-2021, 2021
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This paper describes the results of a recent field campaign in the eastern North Atlantic, where two mass spectrometers were deployed aboard a research aircraft to measure the chemistry of aerosols and trace gases. Very clean conditions were found, dominated by local sulfate-rich acidic aerosol and very aged organics. Evidence of
long-range transport of aerosols from the continents was also identified.
Jens Redemann, Robert Wood, Paquita Zuidema, Sarah J. Doherty, Bernadette Luna, Samuel E. LeBlanc, Michael S. Diamond, Yohei Shinozuka, Ian Y. Chang, Rei Ueyama, Leonhard Pfister, Ju-Mee Ryoo, Amie N. Dobracki, Arlindo M. da Silva, Karla M. Longo, Meloë S. Kacenelenbogen, Connor J. Flynn, Kristina Pistone, Nichola M. Knox, Stuart J. Piketh, James M. Haywood, Paola Formenti, Marc Mallet, Philip Stier, Andrew S. Ackerman, Susanne E. Bauer, Ann M. Fridlind, Gregory R. Carmichael, Pablo E. Saide, Gonzalo A. Ferrada, Steven G. Howell, Steffen Freitag, Brian Cairns, Brent N. Holben, Kirk D. Knobelspiesse, Simone Tanelli, Tristan S. L'Ecuyer, Andrew M. Dzambo, Ousmane O. Sy, Greg M. McFarquhar, Michael R. Poellot, Siddhant Gupta, Joseph R. O'Brien, Athanasios Nenes, Mary Kacarab, Jenny P. S. Wong, Jennifer D. Small-Griswold, Kenneth L. Thornhill, David Noone, James R. Podolske, K. Sebastian Schmidt, Peter Pilewskie, Hong Chen, Sabrina P. Cochrane, Arthur J. Sedlacek, Timothy J. Lang, Eric Stith, Michal Segal-Rozenhaimer, Richard A. Ferrare, Sharon P. Burton, Chris A. Hostetler, David J. Diner, Felix C. Seidel, Steven E. Platnick, Jeffrey S. Myers, Kerry G. Meyer, Douglas A. Spangenberg, Hal Maring, and Lan Gao
Atmos. Chem. Phys., 21, 1507–1563, https://doi.org/10.5194/acp-21-1507-2021, https://doi.org/10.5194/acp-21-1507-2021, 2021
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Southern Africa produces significant biomass burning emissions whose impacts on regional and global climate are poorly understood. ORACLES (ObseRvations of Aerosols above CLouds and their intEractionS) is a 5-year NASA investigation designed to study the key processes that determine these climate impacts. The main purpose of this paper is to familiarize the broader scientific community with the ORACLES project, the dataset it produced, and the most important initial findings.
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.
Tianle Yuan, Hua Song, Robert Wood, Johannes Mohrmann, Kerry Meyer, Lazaros Oreopoulos, and Steven Platnick
Atmos. Meas. Tech., 13, 6989–6997, https://doi.org/10.5194/amt-13-6989-2020, https://doi.org/10.5194/amt-13-6989-2020, 2020
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We use deep transfer learning techniques to classify satellite cloud images into different morphology types. It achieves the state-of-the-art results and can automatically process a large amount of satellite data. The algorithm will help low-cloud researchers to better understand their mesoscale organizations.
Yohei Shinozuka, Pablo E. Saide, Gonzalo A. Ferrada, Sharon P. Burton, Richard Ferrare, Sarah J. Doherty, Hamish Gordon, Karla Longo, Marc Mallet, Yan Feng, Qiaoqiao Wang, Yafang Cheng, Amie Dobracki, Steffen Freitag, Steven G. Howell, Samuel LeBlanc, Connor Flynn, Michal Segal-Rosenhaimer, Kristina Pistone, James R. Podolske, Eric J. Stith, Joseph Ryan Bennett, Gregory R. Carmichael, Arlindo da Silva, Ravi Govindaraju, Ruby Leung, Yang Zhang, Leonhard Pfister, Ju-Mee Ryoo, Jens Redemann, Robert Wood, and Paquita Zuidema
Atmos. Chem. Phys., 20, 11491–11526, https://doi.org/10.5194/acp-20-11491-2020, https://doi.org/10.5194/acp-20-11491-2020, 2020
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In the southeast Atlantic, well-defined smoke plumes from Africa advect over marine boundary layer cloud decks; both are most extensive around September, when most of the smoke resides in the free troposphere. A framework is put forth for evaluating the performance of a range of global and regional atmospheric composition models against observations made during the NASA ORACLES (ObseRvations of Aerosols above CLouds and their intEractionS) airborne mission in September 2016.
Francesca Gallo, Janek Uin, Stephen Springston, Jian Wang, Guangjie Zheng, Chongai Kuang, Robert Wood, Eduardo B. Azevedo, Allison McComiskey, Fan Mei, Adam Theisen, Jenni Kyrouac, and Allison C. Aiken
Atmos. Chem. Phys., 20, 7553–7573, https://doi.org/10.5194/acp-20-7553-2020, https://doi.org/10.5194/acp-20-7553-2020, 2020
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Continuous high-time-resolution ambient data can include periods when aerosol properties do not represent regional aerosol processes due to high-concentration local events. We develop a novel aerosol mask at the U.S. Department of Energy’s Atmospheric Radiation Measurement (ARM) facility in the eastern North Atlantic (ENA). We use two ground sites to validate the mask, include a comparison with aircraft overflights, and provide guidance to increase data quality at ENA and other locations.
Mary Kacarab, K. Lee Thornhill, Amie Dobracki, Steven G. Howell, Joseph R. O'Brien, Steffen Freitag, Michael R. Poellot, Robert Wood, Paquita Zuidema, Jens Redemann, and Athanasios Nenes
Atmos. Chem. Phys., 20, 3029–3040, https://doi.org/10.5194/acp-20-3029-2020, https://doi.org/10.5194/acp-20-3029-2020, 2020
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We find that extensive biomass burning aerosol plumes from southern Africa can profoundly influence clouds in the southeastern Atlantic. Concurrent variations in vertical velocity, however, are found to magnify the relationship between boundary layer aerosol and the cloud droplet number. Neglecting these covariances may strongly bias the sign and magnitude of aerosol impacts on the cloud droplet number.
Samuel E. LeBlanc, Jens Redemann, Connor Flynn, Kristina Pistone, Meloë Kacenelenbogen, Michal Segal-Rosenheimer, Yohei Shinozuka, Stephen Dunagan, Robert P. Dahlgren, Kerry Meyer, James Podolske, Steven G. Howell, Steffen Freitag, Jennifer Small-Griswold, Brent Holben, Michael Diamond, Robert Wood, Paola Formenti, Stuart Piketh, Gillian Maggs-Kölling, Monja Gerber, and Andreas Namwoonde
Atmos. Chem. Phys., 20, 1565–1590, https://doi.org/10.5194/acp-20-1565-2020, https://doi.org/10.5194/acp-20-1565-2020, 2020
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The southeast Atlantic during August–October experiences layers of smoke from biomass burning over marine stratocumulus clouds. Here we present the light attenuation of the smoke and its dependence in the spatial, vertical, and spectral domain through direct measurements from an airborne platform during September 2016. From our observations of this climatically important smoke, we found an average aerosol optical depth of 0.32 at 500 nm, slightly lower than comparative satellite measurements.
Marc Mallet, Pierre Nabat, Paquita Zuidema, Jens Redemann, Andrew Mark Sayer, Martin Stengel, Sebastian Schmidt, Sabrina Cochrane, Sharon Burton, Richard Ferrare, Kerry Meyer, Pablo Saide, Hiren Jethva, Omar Torres, Robert Wood, David Saint Martin, Romain Roehrig, Christina Hsu, and Paola Formenti
Atmos. Chem. Phys., 19, 4963–4990, https://doi.org/10.5194/acp-19-4963-2019, https://doi.org/10.5194/acp-19-4963-2019, 2019
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The model is able to represent LWP but not the LCF. AOD is consistent over the continent but also over ocean (ACAOD). Differences are observed in SSA due to the absence of internal mixing in ALADIN-Climate. A significant regional gradient of the forcing at TOA is observed. An intense positive forcing is simulated over Gabon. Results highlight the significant effect of enhanced moisture on BBA extinction. The surface dimming modifies the energy budget.
Guangjie Zheng, Yang Wang, Allison C. Aiken, Francesca Gallo, Michael P. Jensen, Pavlos Kollias, Chongai Kuang, Edward Luke, Stephen Springston, Janek Uin, Robert Wood, and Jian Wang
Atmos. Chem. Phys., 18, 17615–17635, https://doi.org/10.5194/acp-18-17615-2018, https://doi.org/10.5194/acp-18-17615-2018, 2018
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Here, we elucidate the key processes that drive marine boundary layer (MBL) aerosol size distribution in the eastern North Atlantic (ENA) using long-term measurements. The governing equations of particle concentration are established for different modes. Particles entrained from the free troposphere represent the major source of MBL cloud condensation nuclei (CCN), contributing both directly to CCN population and indirectly by supplying Aitken-mode particles that grow to CCN in the MBL.
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 S. Diamond, Amie Dobracki, Steffen Freitag, Jennifer D. Small Griswold, Ashley Heikkila, Steven G. Howell, Mary E. Kacarab, James R. Podolske, Pablo E. Saide, and Robert Wood
Atmos. Chem. Phys., 18, 14623–14636, https://doi.org/10.5194/acp-18-14623-2018, https://doi.org/10.5194/acp-18-14623-2018, 2018
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Smoke from Africa can mix into clouds over the southeast Atlantic and create new droplets, which brightens the clouds, reflects more sunlight, and thus cools the region. Using aircraft data from a NASA field campaign, we find that cloud properties are correlated with smoke as expected when the smoke is below the clouds but not when smoke is above the clouds because it takes several days for clouds to mix smoke downward. We recommend methods that can track clouds as they move for future studies.
Daniel P. Grosvenor, Odran Sourdeval, and Robert Wood
Atmos. Meas. Tech., 11, 4273–4289, https://doi.org/10.5194/amt-11-4273-2018, https://doi.org/10.5194/amt-11-4273-2018, 2018
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We provide a parameterized correction to the retrieval of cloud effective radius from satellite instruments to account for the assumption that the retrieved value is representative of that at cloud top, whereas in reality it is representative of that lower down. The error leads to errors (which we quantify) in the retrieved cloud droplet concentrations of up to 38 % for stratocumulus regions and also to liquid water path errors, both of which can be corrected using our parameterizations.
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.
Xiaoli Zhou, Andrew S. Ackerman, Ann M. Fridlind, Robert Wood, and Pavlos Kollias
Atmos. Chem. Phys., 17, 12725–12742, https://doi.org/10.5194/acp-17-12725-2017, https://doi.org/10.5194/acp-17-12725-2017, 2017
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Shallow maritime clouds make a well-known transition from stratocumulus to trade cumulus with flow from the subtropics equatorward. Three-day large-eddy simulations that investigate the potential influence of overlying African biomass burning plumes during that transition indicate that cloud-related impacts are likely substantially cooling to negligible at the top of the atmosphere, with magnitude sensitive to background and perturbation aerosol and cloud properties.
Kuan-Ting O and Robert Wood
Atmos. Chem. Phys., 16, 7239–7249, https://doi.org/10.5194/acp-16-7239-2016, https://doi.org/10.5194/acp-16-7239-2016, 2016
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In this work, based on the well-known formulae of classical nucleation theory (CNT), the temperature at which the mean number of critical embryos inside a droplet is unity is derived from the Boltzmann distribution function and explored as a new simplified approximation for homogeneous freezing temperature. It thus appears that the simplicity of this approximation makes it potentially useful for predicting homogeneous freezing temperatures of water droplets in the atmosphere.
Sam Pennypacker and Allison L. Steiner
Atmos. Chem. Phys. Discuss., https://doi.org/10.5194/acp-2016-289, https://doi.org/10.5194/acp-2016-289, 2016
Revised manuscript has not been submitted
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We examine aerosol-cloud interactions detected in springtime cloud statistics over the Southern Great Plains of the United States in the context of cloud phase, measurement uncertainty and regional meteorology. Satellite retrievals of cloud properties are collocated with surface aerosol measurements over five years. The goal is to frame and motivate further work in what could cause deviations from the traditional theory of aerosol-cloud interactions over a given region.
C. R. Terai, C. S. Bretherton, R. Wood, and G. Painter
Atmos. Chem. Phys., 14, 8071–8088, https://doi.org/10.5194/acp-14-8071-2014, https://doi.org/10.5194/acp-14-8071-2014, 2014
D. P. Grosvenor and R. Wood
Atmos. Chem. Phys., 14, 7291–7321, https://doi.org/10.5194/acp-14-7291-2014, https://doi.org/10.5194/acp-14-7291-2014, 2014
A. Muhlbauer, I. L. McCoy, and R. Wood
Atmos. Chem. Phys., 14, 6695–6716, https://doi.org/10.5194/acp-14-6695-2014, https://doi.org/10.5194/acp-14-6695-2014, 2014
A. H. Berner, C. S. Bretherton, R. Wood, and A. Muhlbauer
Atmos. Chem. Phys., 13, 12549–12572, https://doi.org/10.5194/acp-13-12549-2013, https://doi.org/10.5194/acp-13-12549-2013, 2013
C. R. Terai and R. Wood
Atmos. Chem. Phys., 13, 9899–9914, https://doi.org/10.5194/acp-13-9899-2013, https://doi.org/10.5194/acp-13-9899-2013, 2013
A. Gettelman, H. Morrison, C. R. Terai, and R. Wood
Atmos. Chem. Phys., 13, 9855–9867, https://doi.org/10.5194/acp-13-9855-2013, https://doi.org/10.5194/acp-13-9855-2013, 2013
R. C. George, R. Wood, C. S. Bretherton, and G. Painter
Atmos. Chem. Phys., 13, 6305–6328, https://doi.org/10.5194/acp-13-6305-2013, https://doi.org/10.5194/acp-13-6305-2013, 2013
C. H. Twohy, J. R. Anderson, D. W. Toohey, M. Andrejczuk, A. Adams, M. Lytle, R. C. George, R. Wood, P. Saide, S. Spak, P. Zuidema, and D. Leon
Atmos. Chem. Phys., 13, 2541–2562, https://doi.org/10.5194/acp-13-2541-2013, https://doi.org/10.5194/acp-13-2541-2013, 2013
Related subject area
Subject: Aerosols | Research Activity: Field Measurements | Altitude Range: Troposphere | Science Focus: Physics (physical properties and processes)
Measurement report: Long-term assessment of primary and secondary organic aerosols in the Shanghai megacity throughout China's Clean Air actions since 2010
The evolution of aerosol mixing state derived from a field campaign in Beijing: implications for particle aging timescales in urban atmospheres
Measurement report: Size-resolved particle effective density measured by an AAC-SMPS and implications for chemical composition
Measurement report: Aircraft observations of aerosol and microphysical quantities of stratocumulus in autumn over Guangxi Province, China – daylight variation, vertical distribution, and aerosol–cloud interactions
Hygroscopic aerosols amplify longwave downward radiation in the Arctic
Measurement report: Optical and structural properties of atmospheric water-soluble organic carbon in China – insights from multi-site spectroscopic measurements
Measurement report: The variation properties of aerosol hygroscopic growth related to chemical composition during new particle formation days in a coastal city of Southeast China
In situ vertical observations of the layered structure of air pollution in a continental high-latitude urban boundary layer during winter
Size-resolved hygroscopicity and volatility properties of ambient urban aerosol particles measured by a volatility hygroscopicity tandem differential mobility analyzer system in Beijing
Terrestrial runoff is an important source of biological ice-nucleating particles in Arctic marine systems
Characterization of aerosol over the eastern Mediterranean by polarization-sensitive Raman lidar measurements during A-LIFE – aerosol type classification and type separation
Aerosol spectral optical properties in the Paris urban area and its peri-urban and forested surroundings during summer 2022 from ACROSS surface observations
Measurement report: An investigation of the spatiotemporal variability in aerosols in the mountainous terrain of the upper Colorado River basin using SAIL-Net
Contributions of the synoptic meteorology to the seasonal cloud condensation nuclei cycle over the Southern Ocean
Measurement report: Cloud condensation nuclei (CCN) activity in the South China Sea from shipborne observations during the summer and winter of 2021 – seasonal variation and anthropogenic influence
Source-Dependent Optical Properties and Molecular Characteristics of Atmospheric Brown Carbon
On-road vehicle emission measurements show a significant reduction of black carbon and nitrogen oxides emissions in Euro6c and 6d diesel-powered cars
Measurement report: A comparative analysis of an intensive incursion of fluorescing African dust particles over Puerto Rico and another over Spain
Measurement report: Analysis of aerosol optical depth variation at Zhongshan Station in Antarctica
External particle mixing influences hygroscopicity in a sub-urban area
Long-term observations of black carbon and carbon monoxide in the Poker Flat Research Range, central Alaska, with a focus on forest wildfire emissions
High ice-nucleating particle concentrations associated with Arctic haze in springtime cold-air outbreaks
CCN estimations at a high-altitude remote site: role of organic aerosol variability and hygroscopicity
Aerosol hygroscopicity over the southeast Atlantic Ocean during the biomass burning season – Part 1: From the perspective of scattering enhancement
Spatial, temporal, and meteorological impact of the 26 February 2023 dust storm: increase in particulate matter concentrations across New Mexico and West Texas
Large spatiotemporal variability in aerosol properties over central Argentina during the CACTI field campaign
Microphysical properties of refractory black carbon aerosols for different air masses at a central European background site
Quantification and characterization of primary biological aerosol particles and microbes aerosolized from Baltic seawater
Brownness of organics in anthropogenic biomass burning aerosols over South Asia
Multi-year black carbon observations and modeling close to the largest gas flaring and wildfire regions (Western Siberian Arctic)
Source apportionment of particle number size distribution at the street canyon and urban background sites
Long-range transport of coarse mineral dust: an evaluation of the Met Office Unified Model against aircraft observations
Extreme Saharan dust events expand northward over the Atlantic and Europe, prompting record-breaking PM10 and PM2.5 episodes
Atmospheric black carbon in the metropolitan area of La Paz and El Alto, Bolivia: concentration levels and emission sources
Changing optical properties of black carbon and brown carbon aerosols during long-range transport from the Indo-Gangetic Plain to the equatorial Indian Ocean
Aerosol size distribution properties associated with cold-air outbreaks in the Norwegian Arctic
Ice-nucleating particles active below −24 °C in a Finnish boreal forest and their relationship to bioaerosols
Measurement report: The influence of particle number size distribution and hygroscopicity on the microphysical properties of cloud droplets at a mountain site
Measurements of particle emissions of an A350-941 burning 100 % sustainable aviation fuels in cruise
Vertical distribution of ice nucleating particles over the boreal forest of Hyytiälä, Finland
Multi-year gradient measurements of sea spray fluxes over the Baltic Sea and the North Atlantic Ocean
Measurement report: In situ vertical profiles of below-cloud aerosol over the central Greenland Ice Sheet
Occurrence, abundance, and formation of atmospheric tarballs from a wide range of wildfires in the western US
Measurement report: Contribution of atmospheric new particle formation to ultrafine particle concentration, cloud condensation nuclei, and radiative forcing – results from 5-year observations in central Europe
Simulated contrail-processed aviation soot aerosols are poor ice-nucleating particles at cirrus temperatures
Biological and dust aerosols as sources of ice-nucleating particles in the eastern Mediterranean: source apportionment, atmospheric processing and parameterization
Quantifying the dust direct radiative effect in the southwestern United States: findings from multiyear measurements
How horizontal transport and turbulent mixing impact aerosol particle and precursor concentrations at a background site in the UAE
Markedly different impacts of primary emissions and secondary aerosol formation on aerosol mixing states revealed by simultaneous measurements of CCNC, H(/V)TDMA, and SP2
Phase matrix characterization of long-range transported Saharan dust using multiwavelength polarized polar imaging nephelometry
Haifeng Yu, Yunhua Chang, Lin Cheng, Yusen Duan, and Jianlin Hu
Atmos. Chem. Phys., 25, 5355–5369, https://doi.org/10.5194/acp-25-5355-2025, https://doi.org/10.5194/acp-25-5355-2025, 2025
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This study presents long-term measurements and comprehensive analysis of carbonaceous aerosols in fine particles in Shanghai. We further estimated primary and secondary carbon levels, examining their temporal variations on interannual, monthly, seasonal, and diurnal scales. Through rigorous statistical analysis and correlation studies with meteorological parameters and pollutant concentrations, the origins, formation mechanisms, and spatial distribution patterns of secondary organic carbon were elucidated.
Jieyao Liu, Fang Zhang, Jingye Ren, Lu Chen, Anran Zhang, Zhe Wang, Songjian Zou, Honghao Xu, and Xingyan Yue
Atmos. Chem. Phys., 25, 5075–5086, https://doi.org/10.5194/acp-25-5075-2025, https://doi.org/10.5194/acp-25-5075-2025, 2025
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Particle mixing states and aging timescales are important for the evaluation of aerosol climate effects, but they are poorly parameterized in current models. We unravel the evolution of real-time mixing states and the aging timescale of size-resolved particles based on field measurements in urban Beijing. This study provides an observational basis for accurately parameterizing the aging timescale of aerosol particles in climate models.
Yao Song, Jing Wei, Wenlong Zhao, Jinmei Ding, Xiangyu Pei, Fei Zhang, Zhengning Xu, Ruifang Shi, Ya Wei, Lu Zhang, Lingling Jin, and Zhibin Wang
Atmos. Chem. Phys., 25, 4755–4766, https://doi.org/10.5194/acp-25-4755-2025, https://doi.org/10.5194/acp-25-4755-2025, 2025
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This study investigates the size-resolved effective density (ρeff) of aerosol particles in Hangzhou using a tandem aerodynamic aerosol classifier and scanning mobility particle sizer system. The ρeff values ranged from 1.47 to 1.63 g cm-3, increasing with particle diameter. The relationship between ρeff and the particle diameter varies due to differences in the chemical composition of the particles. A new method to derive the size-resolved chemical composition of particles from ρeff is proposed.
Sihan Liu, Honglei Wang, Delong Zhao, Wei Zhou, Yuanmou Du, Zhengguo Zhang, Peng Cheng, Tianliang Zhao, Yue Ke, Zihao Wu, and Mengyu Huang
Atmos. Chem. Phys., 25, 4151–4165, https://doi.org/10.5194/acp-25-4151-2025, https://doi.org/10.5194/acp-25-4151-2025, 2025
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To understand the effect of aerosols on the vertical distribution of stratocumulus microphysical quantities in southwest China, the daily variation characteristics and formation mechanism of the vertical profiles of stratocumulus microphysical characteristics in this region were described using the data of nine cloud-crossing aircraft observations over Guangxi from 10 October to 3 November 2020.
Denghui Ji, Mathias Palm, Matthias Buschmann, Kerstin Ebell, Marion Maturilli, Xiaoyu Sun, and Justus Notholt
Atmos. Chem. Phys., 25, 3889–3904, https://doi.org/10.5194/acp-25-3889-2025, https://doi.org/10.5194/acp-25-3889-2025, 2025
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Our study explores how certain aerosols, like sea salt, affect infrared heat radiation in the Arctic, potentially speeding up warming. We used advanced technology to measure aerosol composition and found that these particles grow with humidity, significantly increasing their heat-trapping effect in the infrared region, especially in winter. Our findings suggest these aerosols could be a key factor in Arctic warming, emphasizing the importance of understanding aerosols for climate prediction.
Haibiao Chen, Caiqing Yan, Liubin Huang, Lin Du, Yang Yue, Xinfeng Wang, Qingcai Chen, Mingjie Xie, Junwen Liu, Fengwen Wang, Shuhong Fang, Qiaoyun Yang, Hongya Niu, Mei Zheng, Yan Wu, and Likun Xue
Atmos. Chem. Phys., 25, 3647–3667, https://doi.org/10.5194/acp-25-3647-2025, https://doi.org/10.5194/acp-25-3647-2025, 2025
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A comprehensive understanding of the optical properties of brown carbon (BrC) is essential to accurately assess its climatic effects. Based on multi-site spectroscopic measurements, this study demonstrated the significant spatial heterogeneity in the optical and structural properties of water-soluble organic carbon (WSOC) in different regions of China and revealed factors affecting WSOC light absorption and the relationship between fluorophores and light absorption of WSOC.
Lingjun Li, Mengren Li, Xiaolong Fan, Yuping Chen, Ziyi Lin, Anqi Hou, Siqing Zhang, Ronghua Zheng, and Jinsheng Chen
Atmos. Chem. Phys., 25, 3669–3685, https://doi.org/10.5194/acp-25-3669-2025, https://doi.org/10.5194/acp-25-3669-2025, 2025
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Here, we show differences and variations in the aerosol scattering hygroscopic growth factor (f(RH)) between new particle formation (NPF) and non-NPF days and the effect of aerosol chemical compositions on f(RH) in Xiamen with in situ observations. The findings are helpful for the further understanding of aerosol hygroscopicity in a coastal city and the use of hygroscopic growth factors in models of air quality and climate change.
Roman Pohorsky, Andrea Baccarini, Natalie Brett, Brice Barret, Slimane Bekki, Gianluca Pappaccogli, Elsa Dieudonné, Brice Temime-Roussel, Barbara D'Anna, Meeta Cesler-Maloney, Antonio Donateo, Stefano Decesari, Kathy S. Law, William R. Simpson, Javier Fochesatto, Steve R. Arnold, and Julia Schmale
Atmos. Chem. Phys., 25, 3687–3715, https://doi.org/10.5194/acp-25-3687-2025, https://doi.org/10.5194/acp-25-3687-2025, 2025
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This study presents an analysis of vertical measurements of pollution in an Alaskan city during winter. It investigates the relationship between the atmospheric structure and the layering of aerosols and trace gases. Results indicate an overall very shallow surface mixing layer. The height of this layer is strongly influenced by a local shallow wind. The study also provides information on the pollution chemical composition at different altitudes, including pollution signatures from power plants.
Aoyuan Yu, Xiaojing Shen, Qianli Ma, Jiayuan Lu, Xinyao Hu, Yangmei Zhang, Quan Liu, Linlin Liang, Lei Liu, Shuo Liu, Hongfei Tong, Huizheng Che, Xiaoye Zhang, and Junying Sun
Atmos. Chem. Phys., 25, 3389–3412, https://doi.org/10.5194/acp-25-3389-2025, https://doi.org/10.5194/acp-25-3389-2025, 2025
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In this work, we utilized a volatility hygroscopicity tandem differential mobility analyzer (VH-TDMA) to investigate, for the first time, the hygroscopicity and volatility of submicron aerosols, as well as their hygroscopicity after heating, in urban Beijing during the autumn of 2023. We analyzed the size-resolved characteristics of hygroscopicity and volatility, the relationship between hygroscopic and volatile properties, and the hygroscopicity of heated submicron aerosols.
Corina Wieber, Lasse Z. Jensen, Leendert Vergeynst, Lorenz Meire, Thomas Juul-Pedersen, Kai Finster, and Tina Šantl-Temkiv
Atmos. Chem. Phys., 25, 3327–3346, https://doi.org/10.5194/acp-25-3327-2025, https://doi.org/10.5194/acp-25-3327-2025, 2025
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The Arctic region is subject to profound changes due to a warming climate. Ice-nucleating particles (INPs) in the seawater can get transported to the atmosphere and impact cloud formation. However, the sources of characteristics of INPs in the marine areas are poorly understood. We investigated the INPs in seawater from Greenlandic fjords and identified a seasonal variability, with highly active INPs originating from terrestrial sources such as glacial and soil runoff.
Silke Groß, Volker Freudenthaler, Moritz Haarig, Albert Ansmann, Carlos Toledano, David Mateos, Petra Seibert, Rodanthi-Elisavet Mamouri, Argyro Nisantzi, Josef Gasteiger, Maximilian Dollner, Anne Tipka, Manuel Schöberl, Marilena Teri, and Bernadett Weinzierl
Atmos. Chem. Phys., 25, 3191–3211, https://doi.org/10.5194/acp-25-3191-2025, https://doi.org/10.5194/acp-25-3191-2025, 2025
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Aerosols contribute to the largest uncertainties in climate change predictions. The eastern Mediterranean is a hotspot for aerosols with natural and anthropogenic contributions. We present lidar measurements performed during A-LIFE (Absorbing aerosol layers in a changing climate: aging, lifetime and dynamics) to characterize aerosols and aerosol mixtures. We extend current lidar classification and separation schemes and compare them to classification schemes using different methods.
Ludovico Di Antonio, Claudia Di Biagio, Paola Formenti, Aline Gratien, Vincent Michoud, Christopher Cantrell, Astrid Bauville, Antonin Bergé, Mathieu Cazaunau, Servanne Chevaillier, Manuela Cirtog, Patrice Coll, Barbara D'Anna, Joel F. de Brito, David O. De Haan, Juliette R. Dignum, Shravan Deshmukh, Olivier Favez, Pierre-Marie Flaud, Cecile Gaimoz, Lelia N. Hawkins, Julien Kammer, Brigitte Language, Franck Maisonneuve, Griša Močnik, Emilie Perraudin, Jean-Eudes Petit, Prodip Acharja, Laurent Poulain, Pauline Pouyes, Eva Drew Pronovost, Véronique Riffault, Kanuri I. Roundtree, Marwa Shahin, Guillaume Siour, Eric Villenave, Pascal Zapf, Gilles Foret, Jean-François Doussin, and Matthias Beekmann
Atmos. Chem. Phys., 25, 3161–3189, https://doi.org/10.5194/acp-25-3161-2025, https://doi.org/10.5194/acp-25-3161-2025, 2025
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The spectral complex refractive index (CRI) and single scattering albedo were retrieved from submicron aerosol measurements at three sites within the greater Paris area during the ACROSS field campaign (June–July 2022). Measurements revealed urban emission impact on surrounding areas. CRI full period averages at 520 nm were 1.41 – 0.037i (urban), 1.52 – 0.038i (peri-urban), and 1.50 – 0.025i (rural). Organic aerosols dominated the aerosol mass and contributed up to 22 % of absorption at 370 nm.
Leah D. Gibson, Ezra J. T. Levin, Ethan Emerson, Nick Good, Anna Hodshire, Gavin McMeeking, Kate Patterson, Bryan Rainwater, Tom Ramin, and Ben Swanson
Atmos. Chem. Phys., 25, 2745–2762, https://doi.org/10.5194/acp-25-2745-2025, https://doi.org/10.5194/acp-25-2745-2025, 2025
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From fall 2021 to summer 2023, SAIL-Net, a network of six aerosol measurement nodes, was deployed in the East River watershed (Colorado, USA) to study aerosol variability across space and time in mountainous terrain. We found that aerosol variability is influenced by elevation differences, with the most representative site in the region changing seasonally, suggesting aerosol spatial variability also varies seasonally. This work offers a blueprint for future studies in other mountainous regions.
Tahereh Alinejadtabrizi, Yi Huang, Francisco Lang, Steven Siems, Michael Manton, Luis Ackermann, Melita Keywood, Ruhi Humphries, Paul Krummel, Alastair Williams, and Greg Ayers
Atmos. Chem. Phys., 25, 2631–2648, https://doi.org/10.5194/acp-25-2631-2025, https://doi.org/10.5194/acp-25-2631-2025, 2025
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Clouds over the Southern Ocean are crucial to Earth's energy balance, but understanding the factors that control them is complex. Our research examines how weather patterns affect tiny particles called cloud condensation nuclei (CCN), which influence cloud properties. Using data from Kennaook / Cape Grim, we found that winter air from Antarctica brings cleaner conditions with lower CCN, while summer patterns from Australia transport more particles. Precipitation also helps reduce CCN in winter.
Hengjia Ou, Mingfu Cai, Yongyun Zhang, Xue Ni, Baoling Liang, Qibin Sun, Shixin Mai, Cuizhi Sun, Shengzhen Zhou, Haichao Wang, Jiaren Sun, and Jun Zhao
Atmos. Chem. Phys., 25, 2495–2513, https://doi.org/10.5194/acp-25-2495-2025, https://doi.org/10.5194/acp-25-2495-2025, 2025
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Two shipborne observations in the South China Sea (SCS) in summer and winter 2021 were conducted. Our study found aerosol hygroscopicity is higher in the SCS in summer than winter, with significant influences from various terrestrial air masses. Aerosol size distribution had a stronger effect on activation ratio than aerosol hygroscopicity in summer and vice versa in winter. Our study provides valuable information to enhance our understanding of cloud condensation nuclei activities in the SCS.
Jinghao Zhai, Yin Zhang, Pengfei Liu, Yujie Zhang, Antai Zhang, Yaling Zeng, Baohua Cai, Jingyi Zhang, Chunbo Xing, Honglong Yang, Xiaofei Wang, Jianhuai Ye, Chen Wang, Tzung-May Fu, Lei Zhu, Huizhong Shen, Shu Tao, and Xin Yang
EGUsphere, https://doi.org/10.5194/egusphere-2025-463, https://doi.org/10.5194/egusphere-2025-463, 2025
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Our findings show that BrC's optical properties vary by source. Secondary BrC from ozone pollution had the lowest absorption but highest wavelength dependence, while BrC from biomass combustion had the highest absorption with the lowest wavelength dependence. Molecular analysis indicated that CHON species from biomass burning had the strongest light absorption. These insights enhance the accuracy of climate models by highlighting source-specific optical properties of BrC.
Irena Ježek Brecelj, Asta Gregorič, Lucijan Zgonik, Tjaša Rutar, Matic Ivančič, Balint Alfoldy, Griša Močnik, and Martin Rigler
EGUsphere, https://doi.org/10.5194/egusphere-2024-3553, https://doi.org/10.5194/egusphere-2024-3553, 2025
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Following a major car industry scandal involving diesel emissions tests, Europe introduced new testing procedures. However, concerns remained about their effectiveness. Our independent study examined real-world vehicle emissions and revealed encouraging findings: modern diesel cars perform as well as, or even better than, gasoline cars in terms of nitrogen oxides emissions. We found the same pattern for soot particles, challenging common perceptions about diesel's environmental impact.
Bighnaraj Sarangi, Darrel Baumgardner, Ana Isabel Calvo, Benjamin Bolaños-Rosero, Roberto Fraile, Alberto Rodríguez-Fernández, Delia Fernández-González, Carlos Blanco-Alegre, Cátia Gonçalves, Estela D. Vicente, and Olga L. Mayol-Bracero
Atmos. Chem. Phys., 25, 843–865, https://doi.org/10.5194/acp-25-843-2025, https://doi.org/10.5194/acp-25-843-2025, 2025
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Measurements of fluorescing aerosol particle properties have been made during two major African dust events, one over the island of Puerto Rico and the other over the city of León, Spain. The measurements were made with two wideband integrated bioaerosol spectrometers. A significant change in the background aerosol properties, at both locations, is observed when the dust is in the respective regions.
Lijing Chen, Lei Zhang, Yong She, Zhaoliang Zeng, Yu Zheng, Biao Tian, Wenqian Zhang, Zhaohui Liu, Huizheng Che, and Minghu Ding
Atmos. Chem. Phys., 25, 727–739, https://doi.org/10.5194/acp-25-727-2025, https://doi.org/10.5194/acp-25-727-2025, 2025
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Aerosol optical depth (AOD) at Zhongshan Station varies seasonally, with lower values in summer and higher values in winter. Winter and spring AOD increases due to reduced fine-mode particles, while summer and autumn increases are linked to particle growth. Diurnal AOD variation correlates positively with temperature but negatively with wind speed and humidity. Backward trajectories show that aerosols on high-AOD (low-AOD) days primarily originate from the ocean (interior Antarctica).
Shravan Deshmukh, Laurent Poulain, Birgit Wehner, Silvia Henning, Jean-Eudes Petit, Pauline Fombelle, Olivier Favez, Hartmut Herrmann, and Mira Pöhlker
Atmos. Chem. Phys., 25, 741–758, https://doi.org/10.5194/acp-25-741-2025, https://doi.org/10.5194/acp-25-741-2025, 2025
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Aerosol hygroscopicity has been investigated at a sub-urban site in Paris; analysis shows the sub-saturated regime's measured hygroscopicity and the chemically derived hygroscopic growth, shedding light on the large effect of external particle mixing and its influence on predicting hygroscopicity.
Takeshi Kinase, Fumikazu Taketani, Masayuki Takigawa, Chunmao Zhu, Yongwon Kim, Petr Mordovskoi, and Yugo Kanaya
Atmos. Chem. Phys., 25, 143–156, https://doi.org/10.5194/acp-25-143-2025, https://doi.org/10.5194/acp-25-143-2025, 2025
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Boreal forest wildfires in interior Alaska represent an important black carbon (BC) source for the Arctic and surrounding regions. We observed BC and carbon monoxide (CO) concentrations in the Poker Flat Research Range since 2016 and found a positive correlation between the observed BC / ∆CO ratio and fire radiative power (FRP) observed in Alaska and Canada. Our finding suggests the BC emission factor and/or inventory could be potentially improved by using FRP.
Erin N. Raif, Sarah L. Barr, Mark D. Tarn, James B. McQuaid, Martin I. Daily, Steven J. Abel, Paul A. Barrett, Keith N. Bower, Paul R. Field, Kenneth S. Carslaw, and Benjamin J. Murray
Atmos. Chem. Phys., 24, 14045–14072, https://doi.org/10.5194/acp-24-14045-2024, https://doi.org/10.5194/acp-24-14045-2024, 2024
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Ice-nucleating particles (INPs) allow ice to form in clouds at temperatures warmer than −35°C. We measured INP concentrations over the Norwegian and Barents seas in weather events where cold air is ejected from the Arctic. These concentrations were among the highest measured in the Arctic. It is likely that the INPs were transported to the Arctic from distant regions. These results show it is important to consider hemispheric-scale INP processes to understand INP concentrations in the Arctic.
Fernando Rejano, Andrea Casans, Marta Via, Juan Andrés Casquero-Vera, Sonia Castillo, Hassan Lyamani, Alberto Cazorla, Elisabeth Andrews, Daniel Pérez-Ramírez, Andrés Alastuey, Francisco Javier Gómez-Moreno, Lucas Alados-Arboledas, Francisco José Olmo, and Gloria Titos
Atmos. Chem. Phys., 24, 13865–13888, https://doi.org/10.5194/acp-24-13865-2024, https://doi.org/10.5194/acp-24-13865-2024, 2024
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This study provides valuable insights to improve cloud condensation nuclei (CCN) estimations at a high-altitude remote site which is influenced by nearby urban pollution. Understanding the factors that affect CCN estimations is essential to improve the CCN data coverage worldwide and assess aerosol–cloud interactions on a global scale. This is crucial for improving climate models, since aerosol–cloud interactions are the most important source of uncertainty in climate projections.
Lu Zhang, Michal Segal-Rozenhaimer, Haochi Che, Caroline Dang, Junying Sun, Ye Kuang, Paola Formenti, and Steven G. Howell
Atmos. Chem. Phys., 24, 13849–13864, https://doi.org/10.5194/acp-24-13849-2024, https://doi.org/10.5194/acp-24-13849-2024, 2024
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Using airborne measurements over the southeast Atlantic Ocean, we examined how much moisture aerosols take up during Africa’s biomass burning season. Our study revealed the important role of organic aerosols and introduced a predictive model for moisture uptake, accounting for organics, sulfate, and black carbon, summarizing results from various campaigns. These findings improve our understanding of aerosol–moisture interactions and their radiative effects in this climatically critical region.
Mary C. Robinson, Kaitlin Schueth, and Karin Ardon-Dryer
Atmos. Chem. Phys., 24, 13733–13750, https://doi.org/10.5194/acp-24-13733-2024, https://doi.org/10.5194/acp-24-13733-2024, 2024
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On 26 February 2023, New Mexico and West Texas were impacted by a severe dust storm. To analyze this storm, 28 meteorological stations and 19 PM2.5 and PM10 stations were used. Dust particles were in the air for 16 h, and dust storm conditions lasted for up to 120 min. Hourly PM2.5 and PM10 concentrations were up to 518 and 9983 µg m−3, respectively. For Lubbock, Texas, the maximum PM2.5 concentrations were the highest ever recorded.
Jerome D. Fast, Adam C. Varble, Fan Mei, Mikhail Pekour, Jason Tomlinson, Alla Zelenyuk, Art J. Sedlacek III, Maria Zawadowicz, and Louisa Emmons
Atmos. Chem. Phys., 24, 13477–13502, https://doi.org/10.5194/acp-24-13477-2024, https://doi.org/10.5194/acp-24-13477-2024, 2024
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Aerosol property measurements recently collected on the ground and by a research aircraft in central Argentina during the Cloud, Aerosol, and Complex Terrain Interactions (CACTI) campaign exhibit large spatial and temporal variability. These measurements coupled with coincident meteorological information provide a valuable data set needed to evaluate and improve model predictions of aerosols in a traditionally data-sparse region of South America.
Yifan Yang, Thomas Müller, Laurent Poulain, Samira Atabakhsh, Bruna A. Holanda, Jens Voigtländer, Shubhi Arora, and Mira L. Pöhlker
EGUsphere, https://doi.org/10.5194/egusphere-2024-3539, https://doi.org/10.5194/egusphere-2024-3539, 2024
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Black carbon (BC) is the major atmospheric aerosol that can absorb light and influence climate. We measured the physical properties of BC at a background site in Germany. In summer, BC particles were smaller and the mixture with other atmospheric components occurred during the daytime. In winter, emissions from residential heating significantly influenced BC's properties. Understanding these characteristics of BC can help improve aerosol optics simulation accuracy.
Julika Zinke, Gabriel Pereira Freitas, Rachel Ann Foster, Paul Zieger, Ernst Douglas Nilsson, Piotr Markuszewski, and Matthew Edward Salter
Atmos. Chem. Phys., 24, 13413–13428, https://doi.org/10.5194/acp-24-13413-2024, https://doi.org/10.5194/acp-24-13413-2024, 2024
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Bioaerosols, which can influence climate and human health, were studied in the Baltic Sea. In May and August 2021, we used a sea spray simulation chamber during two ship-based campaigns to collect and measure these aerosols. We found that microbes were enriched in air compared to seawater. Bacterial diversity was analysed using DNA sequencing. Our methods provided consistent estimates of microbial emission fluxes, aligning with previous studies.
Chimurkar Navinya, Taveen Singh Kapoor, Gupta Anurag, Chandra Venkataraman, Harish C. Phuleria, and Rajan K. Chakrabarty
Atmos. Chem. Phys., 24, 13285–13297, https://doi.org/10.5194/acp-24-13285-2024, https://doi.org/10.5194/acp-24-13285-2024, 2024
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Brown carbon (BrC) aerosols show an order-of-magnitude variation in their light absorption strength. Our understanding of BrC from real-world biomass burning remains limited, complicating the determination of its radiative impact. Our study reports absorption properties of BrC emitted from four major biomass burning sources using field measurements in India. It develops an absorption parameterization for BrC and examines the spatial variability in BrC's absorption strength across India.
Olga B. Popovicheva, Marina A. Chichaeva, Nikolaos Evangeliou, Sabine Eckhardt, Evangelia Diapouli, and Nikolay S. Kasimov
EGUsphere, https://doi.org/10.5194/egusphere-2024-3124, https://doi.org/10.5194/egusphere-2024-3124, 2024
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High-quality measurements of light-absorbing carbon were performed at the polar aerosol station "Island Bely” (Western Siberian Arctic) from 2019 to 2022. The maximum light absorption coefficients were seen in summer due to gas flaring contribution, which is the most significant source in the region. However, the increasing Siberian wildfires had a special share in carbon contribution to this high Arctic station with a persistent smoke layer extending over the whole troposphere in summer.
Sami D. Harni, Minna Aurela, Sanna Saarikoski, Jarkko V. Niemi, Harri Portin, Hanna Manninen, Ville Leinonen, Pasi Aalto, Phil K. Hopke, Tuukka Petäjä, Topi Rönkkö, and Hilkka Timonen
Atmos. Chem. Phys., 24, 12143–12160, https://doi.org/10.5194/acp-24-12143-2024, https://doi.org/10.5194/acp-24-12143-2024, 2024
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In this study, particle number size distribution data were used in a novel way in positive matrix factorization analysis to find aerosol source profiles in the area. Measurements were made in Helsinki at a street canyon and urban background sites between February 2015 and June 2019. Five different aerosol sources were identified. These sources underline the significance of traffic-related emissions in urban environments despite recent improvements in emission reduction technologies.
Natalie G. Ratcliffe, Claire L. Ryder, Nicolas Bellouin, Stephanie Woodward, Anthony Jones, Ben Johnson, Lisa-Maria Wieland, Maximilian Dollner, Josef Gasteiger, and Bernadett Weinzierl
Atmos. Chem. Phys., 24, 12161–12181, https://doi.org/10.5194/acp-24-12161-2024, https://doi.org/10.5194/acp-24-12161-2024, 2024
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Large mineral dust particles are more abundant in the atmosphere than expected and have different impacts on the environment than small particles, which are better represented in climate models. We use aircraft measurements to assess a climate model representation of large-dust transport. We find that the model underestimates the amount of large dust at all stages of transport and that fast removal of the large particles increases this underestimation with distance from the Sahara.
Sergio Rodríguez and Jessica López-Darias
Atmos. Chem. Phys., 24, 12031–12053, https://doi.org/10.5194/acp-24-12031-2024, https://doi.org/10.5194/acp-24-12031-2024, 2024
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Extreme Saharan dust events expanded northward to the Atlantic and Europe, prompting record-breaking PM10 and PM2.5 events. These episodes are caused by low-to-high dipole meteorology during hemispheric anomalies characterized by subtropical anticyclones shifting to higher latitudes, anomalous low pressures beyond the tropics and amplified Rossby waves. Extreme dust events occur in a paradoxical context of a multidecadal decrease in dust emissions, a topic that requires further investigation.
Valeria Mardoñez-Balderrama, Griša Močnik, Marco Pandolfi, Robin L. Modini, Fernando Velarde, Laura Renzi, Angela Marinoni, Jean-Luc Jaffrezo, Isabel Moreno R., Diego Aliaga, Federico Bianchi, Claudia Mohr, Martin Gysel-Beer, Patrick Ginot, Radovan Krejci, Alfred Wiedensohler, Gaëlle Uzu, Marcos Andrade, and Paolo Laj
Atmos. Chem. Phys., 24, 12055–12077, https://doi.org/10.5194/acp-24-12055-2024, https://doi.org/10.5194/acp-24-12055-2024, 2024
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Levels of black carbon (BC) are scarcely reported in the Southern Hemisphere, especially in high-altitude conditions. This study provides insight into the concentration level, variability, and optical properties of BC in La Paz and El Alto and at the Chacaltaya Global Atmosphere Watch Station. Two methods of source apportionment of absorption were tested and compared showing traffic as the main contributor to absorption in the urban area, in addition to biomass and open waste burning.
Krishnakant Budhavant, Mohanan Remani Manoj, Hari Ram Chandrika Rajendran Nair, Samuel Mwaniki Gaita, Henry Holmstrand, Abdus Salam, Ahmed Muslim, Sreedharan Krishnakumari Satheesh, and Örjan Gustafsson
Atmos. Chem. Phys., 24, 11911–11925, https://doi.org/10.5194/acp-24-11911-2024, https://doi.org/10.5194/acp-24-11911-2024, 2024
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The South Asian Pollution Experiment 2018 used access to three strategically located receptor observatories. Observational constraints revealed opposing trends in the mass absorption cross sections of black carbon (BC MAC) and brown carbon (BrC MAC) during long-range transport. Models estimating the climate effects of BC aerosols may have underestimated the ambient BC MAC over distant receptor areas, leading to discrepancies in aerosol absorption predicted by observation-constrained models.
Abigail S. Williams, Jeramy L. Dedrick, Lynn M. Russell, Florian Tornow, Israel Silber, Ann M. Fridlind, Benjamin Swanson, Paul J. DeMott, Paul Zieger, and Radovan Krejci
Atmos. Chem. Phys., 24, 11791–11805, https://doi.org/10.5194/acp-24-11791-2024, https://doi.org/10.5194/acp-24-11791-2024, 2024
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The measured aerosol size distribution modes reveal distinct properties characteristic of cold-air outbreaks in the Norwegian Arctic. We find higher sea spray number concentrations, smaller Hoppel minima, lower effective supersaturations, and accumulation-mode particle scavenging during cold-air outbreaks. These results advance our understanding of cold-air outbreak aerosol–cloud interactions in order to improve their accurate representation in models.
Franziska Vogel, Michael P. Adams, Larissa Lacher, Polly B. Foster, Grace C. E. Porter, Barbara Bertozzi, Kristina Höhler, Julia Schneider, Tobias Schorr, Nsikanabasi S. Umo, Jens Nadolny, Zoé Brasseur, Paavo Heikkilä, Erik S. Thomson, Nicole Büttner, Martin I. Daily, Romy Fösig, Alexander D. Harrison, Jorma Keskinen, Ulrike Proske, Jonathan Duplissy, Markku Kulmala, Tuukka Petäjä, Ottmar Möhler, and Benjamin J. Murray
Atmos. Chem. Phys., 24, 11737–11757, https://doi.org/10.5194/acp-24-11737-2024, https://doi.org/10.5194/acp-24-11737-2024, 2024
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Primary ice formation in clouds strongly influences their properties; hence, it is important to understand the sources of ice-nucleating particles (INPs) and their variability. We present 2 months of INP measurements in a Finnish boreal forest using a new semi-autonomous INP counting device based on gas expansion. These results show strong variability in INP concentrations, and we present a case that the INPs we observe are, at least some of the time, of biological origin.
Xiaojing Shen, Quan Liu, Junying Sun, Wanlin Kong, Qianli Ma, Bing Qi, Lujie Han, Yangmei Zhang, Linlin Liang, Lei Liu, Shuo Liu, Xinyao Hu, Jiayuan Lu, Aoyuan Yu, Huizheng Che, and Xiaoye Zhang
EGUsphere, https://doi.org/10.5194/egusphere-2024-2850, https://doi.org/10.5194/egusphere-2024-2850, 2024
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In this work, an automatic switched inlet system was developed and employed to investigate the aerosols and cloud droplets at a mountain site with frequent cloud processes. It showed different characteristics of cloud residual and interstitial particles. Stronger particle hygroscopicity reduced liquid water content and smaller cloud droplet diameters. This investigation contributes to understanding aerosol-cloud interactions by assessing the impact of aerosol particles on cloud microphysics.
Rebecca Dischl, Daniel Sauer, Christiane Voigt, Theresa Harlaß, Felicitas Sakellariou, Raphael Märkl, Ulrich Schumann, Monika Scheibe, Stefan Kaufmann, Anke Roiger, Andreas Dörnbrack, Charles Renard, Maxime Gauthier, Peter Swann, Paul Madden, Darren Luff, Mark Johnson, Denise Ahrens, Reetu Sallinen, Tobias Schripp, Georg Eckel, Uwe Bauder, and Patrick Le Clercq
Atmos. Chem. Phys., 24, 11255–11273, https://doi.org/10.5194/acp-24-11255-2024, https://doi.org/10.5194/acp-24-11255-2024, 2024
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In-flight measurements of aircraft emissions burning 100 % sustainable aviation fuel (SAF) show reduced particle number concentrations up to 41 % compared to conventional jet fuel. Particle emissions are dependent on engine power setting, flight altitude, and fuel composition. Engine models show a good correlation with measurement results. Future increased prevalence of SAF can positively influence the climate impact of aviation.
Zoé Brasseur, Julia Schneider, Janne Lampilahti, Ville Vakkari, Victoria A. Sinclair, Christina J. Williamson, Carlton Xavier, Dmitri Moisseev, Markus Hartmann, Pyry Poutanen, Markus Lampimäki, Markku Kulmala, Tuukka Petäjä, Katrianne Lehtipalo, Erik S. Thomson, Kristina Höhler, Ottmar Möhler, and Jonathan Duplissy
Atmos. Chem. Phys., 24, 11305–11332, https://doi.org/10.5194/acp-24-11305-2024, https://doi.org/10.5194/acp-24-11305-2024, 2024
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Ice-nucleating particles (INPs) strongly influence the formation of clouds by initiating the formation of ice crystals. However, very little is known about the vertical distribution of INPs in the atmosphere. Here, we present aircraft measurements of INP concentrations above the Finnish boreal forest. Results show that near-surface INPs are efficiently transported and mixed within the boundary layer and occasionally reach the free troposphere.
Piotr Markuszewski, E. Douglas Nilsson, Julika Zinke, E. Monica Mårtensson, Matthew Salter, Przemysław Makuch, Małgorzata Kitowska, Iwona Niedźwiecka-Wróbel, Violetta Drozdowska, Dominik Lis, Tomasz Petelski, Luca Ferrero, and Jacek Piskozub
Atmos. Chem. Phys., 24, 11227–11253, https://doi.org/10.5194/acp-24-11227-2024, https://doi.org/10.5194/acp-24-11227-2024, 2024
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Our research provides new insights into the study of sea spray aerosol (SSA) emissions in the Baltic Sea and North Atlantic. We observed that SSA flux is suppressed during increased marine biological activity in the Baltic Sea. At the same time, the influence of wave age showed higher SSA emissions in the Baltic Sea for younger waves compared to the Atlantic Ocean. These insights underscore the complex interplay between biological activity and physical dynamics in regulating SSA emissions.
Heather Guy, Andrew S. Martin, Erik Olson, Ian M. Brooks, and Ryan R. Neely III
Atmos. Chem. Phys., 24, 11103–11114, https://doi.org/10.5194/acp-24-11103-2024, https://doi.org/10.5194/acp-24-11103-2024, 2024
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Aerosol particles impact cloud properties which influence Greenland Ice Sheet melt. Understanding the aerosol population that interacts with clouds is important for constraining future melt. Measurements of aerosols at cloud height over Greenland are rare, and surface measurements are often used to investigate cloud–aerosol interactions. We use a tethered balloon to measure aerosols up to cloud base and show that surface measurements are often not equivalent to those just below the cloud.
Kouji Adachi, Jack E. Dibb, Joseph M. Katich, Joshua P. Schwarz, Hongyu Guo, Pedro Campuzano-Jost, Jose L. Jimenez, Jeff Peischl, Christopher D. Holmes, and James Crawford
Atmos. Chem. Phys., 24, 10985–11004, https://doi.org/10.5194/acp-24-10985-2024, https://doi.org/10.5194/acp-24-10985-2024, 2024
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We examined aerosol particles from wildfires and identified tarballs (TBs) from the Fire Influence on Regional to Global Environments and Air Quality (FIREX-AQ) campaign. This study reveals the compositions, abundance, sizes, and mixing states of TBs and shows that TBs formed as the smoke aged for up to 5 h. This study provides measurements of TBs from various biomass-burning events and ages, enhancing our knowledge of TB emissions and our understanding of their climate impact.
Jia Sun, Markus Hermann, Kay Weinhold, Maik Merkel, Wolfram Birmili, Yifan Yang, Thomas Tuch, Harald Flentje, Björn Briel, Ludwig Ries, Cedric Couret, Michael Elsasser, Ralf Sohmer, Klaus Wirtz, Frank Meinhardt, Maik Schütze, Olaf Bath, Bryan Hellack, Veli-Matti Kerminen, Markku Kulmala, Nan Ma, and Alfred Wiedensohler
Atmos. Chem. Phys., 24, 10667–10687, https://doi.org/10.5194/acp-24-10667-2024, https://doi.org/10.5194/acp-24-10667-2024, 2024
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We investigated the characteristics of new particle formation (NPF) for various environments from urban background to high Alpine and the impacts of NPF on cloud condensation nuclei and aerosol radiative forcing. NPF features differ between site categories, implying the crucial role of local environmental factors such as the degree of emissions and meteorological conditions. The results also underscore the importance of local environments when assessing the impact of NPF on climate in models.
Baptiste Testa, Lukas Durdina, Jacinta Edebeli, Curdin Spirig, and Zamin A. Kanji
Atmos. Chem. Phys., 24, 10409–10424, https://doi.org/10.5194/acp-24-10409-2024, https://doi.org/10.5194/acp-24-10409-2024, 2024
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Aviation soot residuals released from contrails can become compacted upon sublimation of the ice crystals, generating new voids in the aggregates where ice nucleation can occur. Here we show that contrail-processed soot is highly compact but that it remains unable to form ice at a relative humidity different from that required for the formation of background cirrus from the more ubiquitous aqueous solution droplets, suggesting that it will not perturb cirrus cloud formation via ice nucleation.
Kunfeng Gao, Franziska Vogel, Romanos Foskinis, Stergios Vratolis, Maria I. Gini, Konstantinos Granakis, Anne-Claire Billault-Roux, Paraskevi Georgakaki, Olga Zografou, Prodromos Fetfatzis, Alexis Berne, Alexandros Papayannis, Konstantinos Eleftheridadis, Ottmar Möhler, and Athanasios Nenes
Atmos. Chem. Phys., 24, 9939–9974, https://doi.org/10.5194/acp-24-9939-2024, https://doi.org/10.5194/acp-24-9939-2024, 2024
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Ice nucleating particle (INP) concentrations are required for correct predictions of clouds and precipitation in a changing climate, but they are poorly constrained in climate models. We unravel source contributions to INPs in the eastern Mediterranean and find that biological particles are important, regardless of their origin. The parameterizations developed exhibit superior performance and enable models to consider biological-particle effects on INPs.
Alexandra Kuwano, Amato T. Evan, Blake Walkowiak, and Robert Frouin
Atmos. Chem. Phys., 24, 9843–9868, https://doi.org/10.5194/acp-24-9843-2024, https://doi.org/10.5194/acp-24-9843-2024, 2024
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The dust direct radiative effect is highly uncertain. Here we used new measurements collected over 3 years and during dust storms at a field site in a desert region in the southwestern United States to estimate the regional dust direct radiative effect. We also used novel soil mineralogy retrieved from an airborne spectrometer to estimate this parameter with model output. We find that, in this region, dust has a minimal net cooling effect on this region's climate.
Jutta Kesti, Ewan J. O'Connor, Anne Hirsikko, John Backman, Maria Filioglou, Anu-Maija Sundström, Juha Tonttila, Heikki Lihavainen, Hannele Korhonen, and Eija Asmi
Atmos. Chem. Phys., 24, 9369–9386, https://doi.org/10.5194/acp-24-9369-2024, https://doi.org/10.5194/acp-24-9369-2024, 2024
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The study combines aerosol particle measurements at the surface and vertical profiling of the atmosphere with a scanning Doppler lidar to investigate how particle transportation together with boundary layer evolution can affect particle and SO2 concentrations at the surface in the Arabian Peninsula region. The instrumentation enabled us to see elevated nucleation mode particle and SO2 concentrations at the surface when air masses transported from polluted areas are mixed in the boundary layer.
Jiangchuan Tao, Biao Luo, Weiqi Xu, Gang Zhao, Hanbin Xu, Biao Xue, Miaomiao Zhai, Wanyun Xu, Huarong Zhao, Sanxue Ren, Guangsheng Zhou, Li Liu, Ye Kuang, and Yele Sun
Atmos. Chem. Phys., 24, 9131–9154, https://doi.org/10.5194/acp-24-9131-2024, https://doi.org/10.5194/acp-24-9131-2024, 2024
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Using simultaneous measurements of DMA–CCNC, H(/V)TDMA, and DMA–SP2, impacts of primary emissions and secondary aerosol formations on changes in aerosol physicochemical properties were comprehensively investigated. It was found that intercomparisons among aerosol mixing-state parameters derived from different techniques can help us gain more insight into aerosol physical properties which, in turn, will aid the investigation of emission characteristics and secondary aerosol formation pathways.
Elena Bazo, Daniel Perez-Ramirez, Antonio Valenzuela, Vanderlei Martins, Gloria Titos, Alberto Cazorla, Fernando Rejano, Diego Patrón, Arlett Diaz-Zurita, Francisco Jose Garcia-Izquierdo, David Fuertes, Lucas Alados-Arboledas, and Francisco Jose Olmo
EGUsphere, https://doi.org/10.5194/egusphere-2024-2080, https://doi.org/10.5194/egusphere-2024-2080, 2024
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This works analyses aerosol scattering phase function for transported Saharan dust to the city of Granada – located in southwestern Europe. We use the novel technique polar imaging nephelometry that helps to determine the phase functions using a CCD camara. The capability of measuring with polarized light helps to inferr new properties about the mixture of Saharan dust particles with other of anthropogenic origin.
Cited articles
Abel, S. J., Boutle, I. A., Waite, K., Fox, S., Brown, P. R. A., Lloyd, G.,
and Choularton, T. W.: The role of precipitation in controlling the
transition from stratocumulus to cumulus clouds in a northern hemisphere
cold-air outbreak, J. Atmos. Sci., 74, 2293–2314,
https://doi.org/10.1175/JAS-D-16-0362.1, 2017.
Abel, S. J., Barrett, P. A., Zuidema, P., Zhang, J., Christensen, M., Peers, F., Taylor, J. W., Crawford, I., Bower, K. N., and Flynn, M.: Open cells can decrease the mixing of free-tropospheric biomass burning aerosol into the south-east Atlantic boundary layer, Atmos. Chem. Phys. Discuss., https://doi.org/10.5194/acp-2019-738, in review, 2019.
Adebiyi, A. A. and Zuidema, P.: The role of the southern African easterly
jet in modifying the southeast Atlantic aerosol and cloud environments, Q.
J. Roy. Meteor. Soc., 142, 1574–1589, https://doi.org/10.1002/qj.2765, 2016.
Adebiyi, A. A., Zuidema, P., and Abel, S. J.: The convolution of dynamics and
moisture with the presence of shortwave absorbing aerosols over the
southeast Atlantic, J. Climate, 28, 1997–2024,
https://doi.org/10.1175/JCLI-D-14-00352.1, 2015.
Allen, G., Vaughan, G., Bower, K. N., Williams, P. I., Crosier, J., Flynn,
M., Connolly, P., Hamilton, J. F., Lee, J. D., Saxton, J. E., Watson, N. M.,
Gallagher, M., Coe, H., Allan, J., Choularton, T. W., and Lewis, A. C.:
Aerosol and trace-gas measurements in the Darwin area during the wet season,
J. Geophys. Res.-Atmos., 113, 1–19, https://doi.org/10.1029/2007JD008706, 2008.
Allen, G., Coe, H., Clarke, A., Bretherton, C., Wood, R., Abel, S. J., Barrett, P., Brown, P., George, R., Freitag, S., McNaughton, C., Howell, S., Shank, L., Kapustin, V., Brekhovskikh, V., Kleinman, L., Lee, Y.-N., Springston, S., Toniazzo, T., Krejci, R., Fochesatto, J., Shaw, G., Krecl, P., Brooks, B., McMeeking, G., Bower, K. N., Williams, P. I., Crosier, J., Crawford, I., Connolly, P., Allan, J. D., Covert, D., Bandy, A. R., Russell, L. M., Trembath, J., Bart, M., McQuaid, J. B., Wang, J., and Chand, D.: South East Pacific atmospheric composition and variability sampled along 20∘ S during VOCALS-REx, Atmos. Chem. Phys., 11, 5237–5262, https://doi.org/10.5194/acp-11-5237-2011, 2011.
Anderson, T. L., Charlson, R. J., Winker, D. M., Ogren, J. A., and
Holmén, K.: Mesoscale Variations of Tropospheric Aerosols, J. Atmos.
Sci., 60, 119–136, https://doi.org/10.1175/1520-0469(2003)060<0119:MVOTA>2.0.CO;2, 2003.
Atmospheric Radiation Measurement (ARM): Ultra-High Sensitivity Aerosol Spectrometer (AOSUHSAS). 2016-04-23 to 2017-11-01, updated hourly, ARM Mobile Facility (ASI) Ascension Island, South Atlantic Ocean; AMF1 (M1), compiled by: Uin, J., Salwen, C., and Senum, G., ARM Data Center, https://doi.org/10.5439/1095587, 2016a.
Atmospheric Radiation Measurement (ARM): Condensation Particle Counter (AOSCPCU). 2016-05-20 to 2017-11-03, updated hourly, ARM Mobile Facility (ASI) Ascension Island, South Atlantic Ocean; AMF1 (M1), compiled by: Kuang, C., Salwen, C., and Boyer, M., ARM Data Center, https://doi.org/10.5439/1046186, 2016b.
Atmospheric Radiation Measurement (ARM): MWR Retrievals (MWRRET1LILJCLOU). 2016-05-21 to 2017-11-01, updated hourly, ARM Mobile Facility (ASI) Ascension Island, South Atlantic Ocean; AMF1 (M1), compiled by: Gaustad, K. and Riihimaki, L. ARM Data Center, https://doi.org/10.5439/1027369, 2016c.
Atmospheric Radiation Measurement (ARM): Total Sky Imager (TSISKYCOVER). 2016-05-02 to 2017-10-31, updated hourly, ARM Mobile Facility (ASI) Ascension Island, South Atlantic Ocean; AMF1 (M1), compiled by: Morris, V., ARM Data Center, https://doi.org/10.5439/1025308, 2016d.
Berner, A. H., Bretherton, C. S., and Wood, R.: Large-eddy simulation of mesoscale dynamics and entrainment around a pocket of open cells observed in VOCALS-REx RF06, Atmos. Chem. Phys., 11, 10525–10540, https://doi.org/10.5194/acp-11-10525-2011, 2011.
Boucher, O., Randall, D., Artaxo, P., Bretherton, C., Feingold, G., Forster,
P., Kerminen, V.-M. V.-M., Kondo, Y., Liao, H., Lohmann, U., Rasch, P.,
Satheesh, S. K., Sherwood, S., Stevens, B., Zhang, X. Y., and Zhan, X. Y.:
Clouds and Aerosols, Clim. Chang. 2013 Phys. Sci. Basis. Contrib. Work. Gr. I to Fifth Assess. Rep. Intergov. Panel Clim. Chang., 571–657,
https://doi.org/10.1017/CBO9781107415324.016, 2013.
Bretherton, C. S., McCoy, I. L., Mohrmann, J., Wood, R., Ghate, V.,
Gettelman, A., Bardeen, C. G., Albrecht, B. A., and Zuidema, P.: Cloud,
aerosol, and boundary layer structure across the northeast Pacific
stratocumulus-cumulus transition as observed during CSET, Mon. Weather Rev.,
147, 2083–2103, https://doi.org/10.1175/MWR-D-18-0281.1, 2019.
Cadeddu, M. P., Liljegren, J. C., and Turner, D. D.: The Atmospheric radiation measurement (ARM) program network of microwave radiometers: instrumentation, data, and retrievals, Atmos. Meas. Tech., 6, 2359–2372, https://doi.org/10.5194/amt-6-2359-2013, 2013.
Costantino, L. and Bréon, F.-M.: Aerosol indirect effect on warm clouds over South-East Atlantic, from co-located MODIS and CALIPSO observations, Atmos. Chem. Phys., 13, 69–88, https://doi.org/10.5194/acp-13-69-2013, 2013.
Delamere, J., Bartholomew, M., and Shi, Y.: Laser Disdrometer (PARS2), ARM
Mobile Facility (ASI) Ascension Island, South Atlantic Ocean; AMF1 (M1),
Atmos. Radiat. Meas. Clim. Res. Facil. Data Arch, https://doi.org/10.5439/1150252, 2016.
Devasthale, A. and Thomas, M. A.: A global survey of aerosol-liquid water cloud overlap based on four years of CALIPSO-CALIOP data, Atmos. Chem. Phys., 11, 1143–1154, https://doi.org/10.5194/acp-11-1143-2011, 2011.
Diamond, M. S., Dobracki, A., Freitag, S., Small Griswold, J. D., Heikkila, A., Howell, S. G., Kacarab, M. E., Podolske, J. R., Saide, P. E., and Wood, R.: Time-dependent entrainment of smoke presents an observational challenge for assessing aerosol–cloud interactions over the southeast Atlantic Ocean, Atmos. Chem. Phys., 18, 14623–14636, https://doi.org/10.5194/acp-18-14623-2018, 2018.
Gaustad, K. L., Turner, D. D., and McFarlane, S.: MWRRET Value-Added Product:
The Retrieval of Liquid Water Path and Precipitable Water Vapor from
Microwave Radiometer (MWR) Datasets, U.S. Department of Energy Office of Science Atmospheric Radiation Measurement (ARM) Program, Washington, D.C., USA, 2016.
Gordon, H., Field, P. R., Abel, S. J., Dalvi, M., Grosvenor, D. P., Hill, A. A., Johnson, B. T., Miltenberger, A. K., Yoshioka, M., and Carslaw, K. S.: Large simulated radiative effects of smoke in the south-east Atlantic, Atmos. Chem. Phys., 18, 15261–15289, https://doi.org/10.5194/acp-18-15261-2018, 2018.
Grosvenor, D. P., Sourdeval, O., Zuidema, P., Ackerman, A., Alexandrov, M.
D., Bennartz, R., Boers, R., Cairns, B., Chiu, J. C., Christensen, M.,
Deneke, H., Diamond, M., Feingold, G., Fridlind, A., Hünerbein, A.,
Knist, C., Kollias, P., Marshak, A., McCoy, D., Merk, D., Painemal, D.,
Rausch, J., Rosenfeld, D., Russchenberg, H., Seifert, P., Sinclair, K.,
Stier, P., van Diedenhoven, B., Wendisch, M., Werner, F., Wood, R., Zhang,
Z., and Quaas, J.: Remote Sensing of Droplet Number Concentration in Warm
Clouds: A Review of the Current State of Knowledge and Perspectives, Rev.
Geophys., 56, 409–453, https://doi.org/10.1029/2017RG000593, 2018.
Johnson, B. T., Shine, K. P., and Forster, P. M.: The semi-direct aerosol
effect: Impact of absorbing aerosols on marine stratocumulus, Q. J. Roy.
Meteor. Soc., 130, 1407–1422, https://doi.org/10.1256/qj.03.61, 2004.
Klein, S. A. and Hartmann, D. L.: The seasonal cycle of low stratiform
clouds, J. Climate, 6, 1587–1606, https://doi.org/10.1175/1520-0442(1993)006<1587:TSCOLS>2.0.CO;2, 1993.
Kuang, C.: Ultrafine Condensation Particle Counter Instrument Handbook, U.S. Department of Energy Office of Science Atmospheric Radiation Measurement (ARM) Program,
Washington, D.C., USA, 2016.
Mohrmann, J., Wood, R., McGibbon, J., Eastman, R., and Luke, E.: Drivers of
seasonal variability in marine boundary layer aerosol number concentration
investigated using a steady-state approach, J. Geophys. Res.-Atmos., 123, 1097–1112,
https://doi.org/10.1002/2017JD027443, 2017.
Morris, V.: Total Sky Imager (TSI) Instrument Handbook, U.S. Department of Energy Office of Science Atmospheric Radiation Measurement (ARM) Program, Washington, D.C., USA,
2005.
O'Dell, C. W., Wentz, F. J., and Bennartz, R.: Cloud liquid water path from
satellite-based passive microwave observations: A new climatology over the
global oceans, J. Climate, 21, 1721–1739, https://doi.org/10.1175/2007JCLI1958.1, 2008.
Pennypacker, S. and Wood, R.: A Case Study in Low Aerosol Number
Concentrations Over the Eastern North Atlantic: Implications for Pristine
Conditions in the Remote Marine Boundary Layer, J. Geophys. Res.-Atmos.,
122, 12393–12415, https://doi.org/10.1002/2017JD027493, 2017.
Petters, M. D., Snider, J. R., Stevens, B., Vali, G., Faloona, I., and
Russell, L. M.: Accumulation mode aerosol, pockets of open cells, and
particle nucleation in the remote subtropical Pacific marine boundary layer,
J. Geophys. Res.-Atmos., 111, 1–15, https://doi.org/10.1029/2004JD005694, 2006.
Rajapakshe, C., Zhang, Z., Yorks, J. E., Yu, H., Tan, Q., Meyer, K.,
Platnick, S., and Winker, D. M.: Seasonally transported aerosol layers over
southeast Atlantic are closer to underlying clouds than previously reported,
Geophys. Res. Lett., 44, 5818–5825, https://doi.org/10.1002/2017GL073559, 2017.
Rosenfeld, D., Sherwood, S., Wood, R., and Donner, L.: Climate Effects of
Aerosol-Cloud Interactions, Science, 343, 379–380,
https://doi.org/10.1126/science.1247490, 2014.
Sakaeda, N., Wood, R., and Rasch, P. J.: Direct and semidirect aerosol
effects of southern African biomass burning aerosol, J. Geophys. Res.-Atmos., 116, 1–20, https://doi.org/10.1029/2010JD015540, 2011.
Sedlacek, A. J.: Single-Particle Soot Photometer (SP2) Instrument
Handbook, U.S. Department of Energy Office of Science Atmospheric Radiation Measurement (ARM) Program, Washington, D.C., USA, 2017.
Shank, L. M., Howell, S., Clarke, A. D., Freitag, S., Brekhovskikh, V., Kapustin, V., McNaughton, C., Campos, T., and Wood, R.: Organic matter and non-refractory aerosol over the remote Southeast Pacific: oceanic and combustion sources, Atmos. Chem. Phys., 12, 557–576, https://doi.org/10.5194/acp-12-557-2012, 2012.
Sharon, T. M., Albrecht, B. A., Jonsson, H. H., Minnis, P., Khaiyer, M. M.,
van Reken, T. M., Seinfeld, J., and Flagan, R.: Aerosol and Cloud
Microphysical Characteristics of Rifts and Gradients in Maritime
Stratocumulus Clouds, J. Atmos. Sci., 63, 983–997,
https://doi.org/10.1175/JAS3667.1, 2006.
Stein, A. F., Draxler, R. R., Rolph, G. D., Stunder, B. J. B., Cohen, M. D.,
and Ngan, F.: NOAA's HYSPLIT atmospheric transport and dispersion modeling
system, B. Am. Meteorol. Soc., 96, 2059–2077,
https://doi.org/10.1175/BAMS-D-14-00110.1, 2015.
Stevens, B. and Feingold, G.: Untangling aerosol effects on clouds and
precipitation in a buffered system, Nature, 461, 607–613, https://doi.org/10.1038/nature08281, 2009.
Terai, C. R., Bretherton, C. S., Wood, R., and Painter, G.: Aircraft observations of aerosol, cloud, precipitation, and boundary layer properties in pockets of open cells over the southeast Pacific, Atmos. Chem. Phys., 14, 8071–8088, https://doi.org/10.5194/acp-14-8071-2014, 2014.
Tummon, F., Solmon, F., Liousse, C., and Tadross, M.: Simulation of the
direct and semidirect aerosol effects on the southern Africa regional
climate during the biomass burning season, J. Geophys. Res.-Atmos., 115,
1–20, https://doi.org/10.1029/2009JD013738, 2010.
Uin, J.: Ultra-High-Sensitivity Aerosol Spectrometer Instrument Handbook, U.S. Department of Energy Office of Science Atmospheric Radiation Measurement (ARM) Program,
Washington, D.C., USA, 2016.
Wang, H. and Feingold, G.: Modeling Mesoscale Cellular Structures and
Drizzle in Marine Stratocumulus. Part II: The Microphysics and Dynamics of
the Boundary Region between Open and Closed Cells, J. Atmos. Sci., 66,
3257–3275, https://doi.org/10.1175/2009JAS3120.1, 2009.
Wang, H., Feingold, G., Wood, R., and Kazil, J.: Modelling microphysical and meteorological controls on precipitation and cloud cellular structures in Southeast Pacific stratocumulus, Atmos. Chem. Phys., 10, 6347–6362, https://doi.org/10.5194/acp-10-6347-2010, 2010.
Wood, R.: Rate of loss of cloud droplets by coalescence in warm clouds, J.
Geophys. Res.-Atmos., 111, 1–6, https://doi.org/10.1029/2006JD007553, 2006.
Wood, R., Leon, D., Lebsock, M., Snider, J., and Clarke, A. D.: Precipitation
driving of droplet concentration variability in marine low clouds, J.
Geophys. Res.-Atmos., 117, D19210, https://doi.org/10.1029/2012JD018305, 2012.
Wood, R., Stemmler, J. D., Rémillard, J., and Jefferson, A.: Low CCN
concentration air masses over the eastern North Atlantic: seasonality,
meteorology and drivers, J. Geophys. Res.-Atmos., 122, 1203–1223,
https://doi.org/10.1002/2016JD025557, 2017.
Wood, R., O, K.-T., Bretherton, C. S., Mohrmann, J., Albrecht, B. A.,
Zuidema, P., Ghate, V., Schwartz, C., Eloranta, E., Glienke, S., Shaw, R.,
and Fugal, J.: Ultraclean layers and optically thin clouds in the
stratocumulus to cumulus transition: part I. Observations, J. Atmos. Sci.,
75, 1631–1652, https://doi.org/10.1175/JAS-D-17-0213.1, 2018.
Yamaguchi, T. and Feingold, G.: On the relationship between open cellular convective cloud patterns and the spatial distribution of precipitation, Atmos. Chem. Phys., 15, 1237–1251, https://doi.org/10.5194/acp-15-1237-2015, 2015.
Yamaguchi, T., Feingold, G., Kazil, J., and McComiskey, A.: Stratocumulus to
cumulus transition in the presence of elevated smoke layers, Geophys. Res.
Lett., 42, 10478–10485, https://doi.org/10.1002/2015GL066544, 2015.
Zhou, X., Ackerman, A. S., Fridlind, A. M., Wood, R., and Kollias, P.: Impacts of solar-absorbing aerosol layers on the transition of stratocumulus to trade cumulus clouds, Atmos. Chem. Phys., 17, 12725–12742, https://doi.org/10.5194/acp-17-12725-2017, 2017.
Zuidema, P., Chang, P., Medeiros, B., Kirtman, B. P., Mechoso, R., Schneider, E. K., Toniazzo, T., Richter, I., Small, R. J., Bellomo, K., Brandt, P., De Szoeke, S., Farrar, J. T., Jung, E., Kato, S., Li, M., Patricola, C., Wang, Z., Wood, R., and Xu, Z.: Challenges and prospects for reducing coupled climate model SST biases in the eastern tropical atlantic and pacific oceans: The U.S. Clivar eastern tropical oceans synthesis working group, B. Am. Meteorol. Soc., 97, 2305–2327, https://doi.org/10.1175/BAMS-D-15-00274.1, 2016a.
Zuidema, P., Alvarado, M., Chiu, C., Deszoeke, S., Fairall, C., Feingold,
G., Ghan, S., Haywood, J., Kollias, P., Lewis, E., Mcfarguhar, G.,
Mccomiskey, A., Mechem, D., Redemann, J., Romps, D., Turner, D., Wang, H.,
Wood, R., Yuter, S., and Zhu, P.: Layered Atlantic Smoke Interactions with
Clouds (LASIC) Science Plan, DOE/SC-ARM-14-037, U.S. Dep. Energy, Off. Sci., available at: https://www.osti.gov/biblio/1232658-layered-atlantic-smoke-interactions-clouds-lasic-science-plan (last access: 21 February 2020), 2016b.
Zuidema, P., Redemann, J., Haywood, J., Wood, R., Piketh, S., Hipondoka, M.,
and Formenti, P.: Smoke and clouds above the southeast Atlantic: Upcoming
field campaigns probe absorbing aerosol's impact on climate, B. Am.
Meteorol. Soc., 97, 1131–1135, https://doi.org/10.1175/BAMS-D-15-00082.1, 2016c.
Zuidema, P., Sedlacek III, A. J., Flynn, C., Springston, S., Delgadillo, R.,
Zhang, J., Aiken, A. C., Koontz, A., Muradyan, P., and Zuidema, P.: The
Ascension Island boundary layer in the remote southeast Atlantic is often
smoky, Geophys. Res. Lett., 45, 4456–4465, https://doi.org/10.1002/2017GL076926, 2018.
Short summary
Using observations from instruments deployed to a small island in the southeast Atlantic, we study days when the atmospheric concentrations of particles near the surface are exceptionally low. Interestingly, these ultra-clean boundary layers occur in the same months as the smokiest boundary layers associated with biomass burning in Africa. We find evidence that enhancements in drizzle scavenging, on top of a seasonal maximum in cloudiness and precipitation, likely drive these conditions.
Using observations from instruments deployed to a small island in the southeast Atlantic, we...
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