Articles | Volume 16, issue 2
Research article 29 Jan 2016
Research article | 29 Jan 2016
Vertical profiles of optical and microphysical particle properties above the northern Indian Ocean during CARDEX 2012
F. Höpner et al.
No articles found.
Erik Johansson, Abhay Devasthale, Michael Tjernström, Annica M. L. Ekman, Klaus Wyser, and Tristan L'Ecuyer
Geosci. Model Dev., 14, 4087–4101,Short summary
Understanding the coupling of clouds to large-scale circulation is a grand challenge for the climate community. Cloud radiative heating (CRH) is a key parameter in this coupling and is therefore essential to model realistically. We, therefore, evaluate a climate model against satellite observations. Our findings indicate good agreement in the seasonal pattern of CRH even if the magnitude differs. We also find that increasing the horizontal resolution in the model has little effect on the CRH.
Georgia Sotiropoulou, Luisa Ickes, Athanasios Nenes, and Annica M. L. Ekman
Atmos. Chem. Phys., 21, 9741–9760,Short summary
Mixed-phase clouds are a large source of uncertainty in projections of the Arctic climate. This is partly due to the poor representation of the cloud ice formation processes. Implementing a parameterization for ice multiplication due to mechanical breakup upon collision of two ice particles in a high-resolution model improves cloud ice phase representation; however, cloud liquid remains overestimated.
Alejandro Baró Pérez, Abhay Devasthale, Frida A.-M. Bender, and Annica M. L. Ekman
Atmos. Chem. Phys., 21, 6053–6077,Short summary
We study the impacts of above-cloud biomass burning plumes on radiation and clouds over the southeast Atlantic using data derived from satellite observations and data-constrained model simulations. A substantial amount of the aerosol within the plumes is not classified as smoke by the satellite. The atmosphere warms more with increasing smoke aerosol loading. No clear influence of aerosol type, loading, or moisture within the overlying aerosol plumes is detected on the cloud top cooling rates.
Ines Bulatovic, Adele L. Igel, Caroline Leck, Jost Heintzenberg, Ilona Riipinen, and Annica M. L. Ekman
Atmos. Chem. Phys., 21, 3871–3897,Short summary
We use detailed numerical modelling to show that small aerosol particles (diameters ~25–80 nm; so-called Aitken mode particles) significantly influence low-level cloud properties in the clean summertime high Arctic. The small particles can help sustain clouds when the concentration of larger particles is low (<10–20 cm-3). Measurements from four different observational campaigns in the high Arctic support the modelling results as they indicate that Aitken mode aerosols are frequently activated.
Lena Frey, Frida A.-M. Bender, and Gunilla Svensson
Atmos. Chem. Phys., 21, 577–595,Short summary
We investigate the vertical distribution of aerosol in the climate model NorESM1-M in five regions of marine stratocumulus clouds. We thereby analyze the total aerosol extinction to facilitate a comparison with satellite data. We find that the model underestimates aerosol extinction throughout the troposphere, especially elevated aerosol layers. Further, we perform sensitivity experiments to identify the processes most important for vertical aerosol distribution in our model.
Johannes Quaas, Antti Arola, Brian Cairns, Matthew Christensen, Hartwig Deneke, Annica M. L. Ekman, Graham Feingold, Ann Fridlind, Edward Gryspeerdt, Otto Hasekamp, Zhanqing Li, Antti Lipponen, Po-Lun Ma, Johannes Mülmenstädt, Athanasios Nenes, Joyce E. Penner, Daniel Rosenfeld, Roland Schrödner, Kenneth Sinclair, Odran Sourdeval, Philip Stier, Matthias Tesche, Bastiaan van Diedenhoven, and Manfred Wendisch
Atmos. Chem. Phys., 20, 15079–15099,Short summary
Anthropogenic pollution particles – aerosols – serve as cloud condensation nuclei and thus increase cloud droplet concentration and the clouds' reflection of sunlight (a cooling effect on climate). This Twomey effect is poorly constrained by models and requires satellite data for better quantification. The review summarizes the challenges in properly doing so and outlines avenues for progress towards a better use of aerosol retrievals and better retrievals of droplet concentrations.
Laura J. Wilcox, Zhen Liu, Bjørn H. Samset, Ed Hawkins, Marianne T. Lund, Kalle Nordling, Sabine Undorf, Massimo Bollasina, Annica M. L. Ekman, Srinath Krishnan, Joonas Merikanto, and Andrew G. Turner
Atmos. Chem. Phys., 20, 11955–11977,Short summary
Projected changes in man-made aerosol range from large reductions to moderate increases in emissions until 2050. Rapid reductions between the present and the 2050s lead to enhanced increases in global and Asian summer monsoon precipitation relative to scenarios with continued increases in aerosol. Relative magnitude and spatial distribution of aerosol changes are particularly important for South Asian summer monsoon precipitation changes, affecting the sign of the trend in the coming decades.
Luisa Ickes, Grace C. E. Porter, Robert Wagner, Michael P. Adams, Sascha Bierbauer, Allan K. Bertram, Merete Bilde, Sigurd Christiansen, Annica M. L. Ekman, Elena Gorokhova, Kristina Höhler, Alexei A. Kiselev, Caroline Leck, Ottmar Möhler, Benjamin J. Murray, Thea Schiebel, Romy Ullrich, and Matthew E. Salter
Atmos. Chem. Phys., 20, 11089–11117,Short summary
The Arctic is a region where aerosols are scarce. Sea spray might be a potential source of aerosols acting as ice-nucleating particles. We investigate two common phytoplankton species (Melosira arctica and Skeletonema marinoi) and present their ice nucleation activity in comparison with Arctic seawater microlayer samples from different field campaigns. We also aim to understand the aerosolization process of marine biological samples and the potential effect on the ice nucleation activity.
W. Richard Leaitch, John K. Kodros, Megan D. Willis, Sarah Hanna, Hannes Schulz, Elisabeth Andrews, Heiko Bozem, Julia Burkart, Peter Hoor, Felicia Kolonjari, John A. Ogren, Sangeeta Sharma, Meng Si, Knut von Salzen, Allan K. Bertram, Andreas Herber, Jonathan P. D. Abbatt, and Jeffrey R. Pierce
Atmos. Chem. Phys., 20, 10545–10563,Short summary
Black carbon is a factor in the warming of the Arctic atmosphere due to its ability to absorb light, but the uncertainty is high and few observations have been made in the high Arctic above 80° N. We combine airborne and ground-based observations in the springtime Arctic, at and above 80° N, with simulations from a global model to show that light absorption by black carbon may be much larger than modelled. However, the uncertainty remains high.
Maria Sand, Terje K. Berntsen, Annica M. L. Ekman, Hans-Christen Hansson, and Anna Lewinschal
Atmos. Chem. Phys., 20, 3079–3089,Short summary
There has been a growing interest in reducing emissions of soot particles to slow global warming and improve air quality. However, estimating the effect of reduced emissions is complex, as soot particles absorb solar radiation and influence heating rates, clouds, and humidity and can influence climate far outside their emission region. Here we investigate the impact of soot emitted in four major emissions areas, using different emissions rates, to see whether location and magnitude matter.
Md. Robiul Islam, Thilina Jayarathne, Isobel J. Simpson, Benjamin Werden, John Maben, Ashley Gilbert, Puppala S. Praveen, Sagar Adhikari, Arnico K. Panday, Maheswar Rupakheti, Donald R. Blake, Robert J. Yokelson, Peter F. DeCarlo, William C. Keene, and Elizabeth A. Stone
Atmos. Chem. Phys., 20, 2927–2951,Short summary
The Kathmandu Valley experiences high levels of air pollution. In this study, atmospheric gases and particulate matter were characterized by online and off-line measurements, with an emphasis on understanding their sources. The major sources of particulate matter and trace gases were identified as garbage burning, biomass burning, and vehicles. The majority of secondary organic aerosol was attributed to anthropogenic precursors, while a minority was attributed to biogenic gases.
Georgia Sotiropoulou, Sylvia Sullivan, Julien Savre, Gary Lloyd, Thomas Lachlan-Cope, Annica M. L. Ekman, and Athanasios Nenes
Atmos. Chem. Phys., 20, 1301–1316,Short summary
Arctic clouds constitute a large source of uncertainty in predictions of future climate. Observations indicate that the number concentration of cloud ice crystals exceeds the concentration of aerosols that can act as ice-nucleating particles (INPs). We show that ice multiplication due to mechanical break-up upon collisions between the few primary ice crystals (formed from INPs) can explain the discrepancy. Including a description of the process in climate models can improve cloud representation.
Laura J. Wilcox, Nick Dunstone, Anna Lewinschal, Massimo Bollasina, Annica M. L. Ekman, and Eleanor J. Highwood
Atmos. Chem. Phys., 19, 9081–9095,Short summary
Asian anthropogenic aerosol emissions have increased rapidly since 1980. In winter, this has resulted in warming over China and cooling over India. Using models of different levels of complexity, we show that Asian-aerosol-induced heating anomalies in the western and northern North Pacific establish a circulation pattern that causes cooling in North America and Europe. This connection makes these regions potentially sensitive to any reductions of Asian aerosol emissions in the near future.
Anna Lewinschal, Annica M. L. Ekman, Hans-Christen Hansson, Maria Sand, Terje K. Berntsen, and Joakim Langner
Atmos. Chem. Phys., 19, 2385–2403,Short summary
We use a global climate model to study how anthropogenic emissions of short-lived atmospheric particles in different parts of the world influence the global temperature distribution. We find that the global mean temperature change per unit emission is similar for all emission regions, and the largest temperature response is found in the Arctic no matter where the emissions occur. However, for European emissions, the temperature change per unit emission is found to depend on emission strength.
Michael Boy, Erik S. Thomson, Juan-C. Acosta Navarro, Olafur Arnalds, Ekaterina Batchvarova, Jaana Bäck, Frank Berninger, Merete Bilde, Zoé Brasseur, Pavla Dagsson-Waldhauserova, Dimitri Castarède, Maryam Dalirian, Gerrit de Leeuw, Monika Dragosics, Ella-Maria Duplissy, Jonathan Duplissy, Annica M. L. Ekman, Keyan Fang, Jean-Charles Gallet, Marianne Glasius, Sven-Erik Gryning, Henrik Grythe, Hans-Christen Hansson, Margareta Hansson, Elisabeth Isaksson, Trond Iversen, Ingibjorg Jonsdottir, Ville Kasurinen, Alf Kirkevåg, Atte Korhola, Radovan Krejci, Jon Egill Kristjansson, Hanna K. Lappalainen, Antti Lauri, Matti Leppäranta, Heikki Lihavainen, Risto Makkonen, Andreas Massling, Outi Meinander, E. Douglas Nilsson, Haraldur Olafsson, Jan B. C. Pettersson, Nønne L. Prisle, Ilona Riipinen, Pontus Roldin, Meri Ruppel, Matthew Salter, Maria Sand, Øyvind Seland, Heikki Seppä, Henrik Skov, Joana Soares, Andreas Stohl, Johan Ström, Jonas Svensson, Erik Swietlicki, Ksenia Tabakova, Throstur Thorsteinsson, Aki Virkkula, Gesa A. Weyhenmeyer, Yusheng Wu, Paul Zieger, and Markku Kulmala
Atmos. Chem. Phys., 19, 2015–2061,Short summary
The Nordic Centre of Excellence CRAICC (Cryosphere–Atmosphere Interactions in a Changing Arctic Climate), funded by NordForsk in the years 2011–2016, is the largest joint Nordic research and innovation initiative to date and aimed to strengthen research and innovation regarding climate change issues in the Nordic region. The paper presents an overview of the main scientific topics investigated and provides a state-of-the-art comprehensive summary of what has been achieved in CRAICC.
J. Douglas Goetz, Michael R. Giordano, Chelsea E. Stockwell, Ted J. Christian, Rashmi Maharjan, Sagar Adhikari, Prakash V. Bhave, Puppala S. Praveen, Arnico K. Panday, Thilina Jayarathne, Elizabeth A. Stone, Robert J. Yokelson, and Peter F. DeCarlo
Atmos. Chem. Phys., 18, 14653–14679,Short summary
Size distributions and emission factors of submicron aerosol were quantified using online techniques for a variety of common but under-sampled combustion sources in South Asia: wood and dung cooking fires, groundwater pumps, brick kilns, trash burning, and open burning of crop residues. Optical properties (brown carbon light absorption and the absorption Ångström exponent, AAE) of the emissions were also investigated. Contextual comparisons to the literature and other NAMaSTE results were made.
Xiaona Shang, Meehye Lee, Saehee Lim, Örjan Gustafsson, Gangwoong Lee, and Limseok Chang
Atmos. Chem. Phys. Discuss.,
Preprint withdrawnShort summary
At Gosan Climate Observatory, the three main sources including anthropogenic pollution, soil dust, and agricultural fertilizer were distinguished for PM10, PM2.5, and PM1, which accounted for 71 % of the total variances for their mass and composition. The mass of mean + σ were comparable to the 90th percentile and the top 10 % implies the substantial impact of soil dust and haze pollution. In PM2.5, the contribution from non-combustion source such as soil dust should not be ignored.
Lauren Schmeisser, John Backman, John A. Ogren, Elisabeth Andrews, Eija Asmi, Sandra Starkweather, Taneil Uttal, Markus Fiebig, Sangeeta Sharma, Kostas Eleftheriadis, Stergios Vratolis, Michael Bergin, Peter Tunved, and Anne Jefferson
Atmos. Chem. Phys., 18, 11599–11622,Short summary
This paper presents pan-Arctic seasonality of in-situ-measured aerosol optical properties from six surface monitoring sites. The analysis provides insight into aerosol annual variability throughout the region – something that is not possible using only measurements from satellite or temporary aircraft campaigns. This paper shows that the large spatiotemporal variability in aerosol optical properties needs to be taken into account in order to properly represent Arctic climate.
Robin G. Stevens, Katharina Loewe, Christopher Dearden, Antonios Dimitrelos, Anna Possner, Gesa K. Eirund, Tomi Raatikainen, Adrian A. Hill, Benjamin J. Shipway, Jonathan Wilkinson, Sami Romakkaniemi, Juha Tonttila, Ari Laaksonen, Hannele Korhonen, Paul Connolly, Ulrike Lohmann, Corinna Hoose, Annica M. L. Ekman, Ken S. Carslaw, and Paul R. Field
Atmos. Chem. Phys., 18, 11041–11071,Short summary
We perform a model intercomparison of summertime high Arctic clouds. Observed concentrations of aerosol particles necessary for cloud formation fell to extremely low values, coincident with a transition from cloudy to nearly cloud-free conditions. Previous analyses have suggested that at these low concentrations, the radiative properties of the clouds are determined primarily by these particle concentrations. The model results strongly support this hypothesis.
Héctor Rivera, John A. Ogren, Elisabeth Andrews, and Olga L. Mayol-Bracero
Atmos. Chem. Phys. Discuss.,
Preprint withdrawnShort summary
This paper is about the variations of the physicochemical and optical properties of natural aerosols in Puerto Rico. We compare/contrast the implications of the loads, sizes, scattering, and absorbing properties of marine, African dust, and volcanic aerosols in the radiative forcing efficiency. We discuss how we classified these aerosols by source and their relative contribution to the radiative forcing efficiency. We contrast the change in temperature due to African dust and volcanic aerosols.
Quentin Bourgeois, Annica M. L. Ekman, Jean-Baptiste Renard, Radovan Krejci, Abhay Devasthale, Frida A.-M. Bender, Ilona Riipinen, Gwenaël Berthet, and Jason L. Tackett
Atmos. Chem. Phys., 18, 7709–7720,Short summary
The altitude of aerosols is crucial as they can impact cloud formation and radiation. In this study, satellite observations have been used to characterize the global aerosol optical depth (AOD) in the boundary layer and the free troposphere. The free troposphere contributes 39 % to the global AOD during daytime. Overall, the results have implications for the description of budgets, sources, sinks and transport of aerosol particles as presently described in the atmospheric model.
Chaman Gul, Siva Praveen Puppala, Shichang Kang, Bhupesh Adhikary, Yulan Zhang, Shaukat Ali, Yang Li, and Xiaofei Li
Atmos. Chem. Phys., 18, 4981–5000,Short summary
Snow and ice samples were collected from six glaciers and multiple mountain valleys from northern Pakistan. Samples were analyzed for black carbon and water-insoluble organic carbon. Relatively high concentrations of black carbon, organic carbon, and dust were reported. Snow albedo and radiative forcing were estimated for the snow samples. Possible source regions of pollutants were identified through various techniques.
Julia Schmale, Silvia Henning, Stefano Decesari, Bas Henzing, Helmi Keskinen, Karine Sellegri, Jurgita Ovadnevaite, Mira L. Pöhlker, Joel Brito, Aikaterini Bougiatioti, Adam Kristensson, Nikos Kalivitis, Iasonas Stavroulas, Samara Carbone, Anne Jefferson, Minsu Park, Patrick Schlag, Yoko Iwamoto, Pasi Aalto, Mikko Äijälä, Nicolas Bukowiecki, Mikael Ehn, Göran Frank, Roman Fröhlich, Arnoud Frumau, Erik Herrmann, Hartmut Herrmann, Rupert Holzinger, Gerard Kos, Markku Kulmala, Nikolaos Mihalopoulos, Athanasios Nenes, Colin O'Dowd, Tuukka Petäjä, David Picard, Christopher Pöhlker, Ulrich Pöschl, Laurent Poulain, André Stephan Henry Prévôt, Erik Swietlicki, Meinrat O. Andreae, Paulo Artaxo, Alfred Wiedensohler, John Ogren, Atsushi Matsuki, Seong Soo Yum, Frank Stratmann, Urs Baltensperger, and Martin Gysel
Atmos. Chem. Phys., 18, 2853–2881,Short summary
Collocated long-term observations of cloud condensation nuclei (CCN) number concentrations, particle number size distributions and chemical composition from 12 sites are synthesized. Observations cover coastal environments, the Arctic, the Mediterranean, the boreal and rain forest, high alpine and continental background sites, and Monsoon-influenced areas. We interpret regional and seasonal variability. CCN concentrations are predicted with the κ–Köhler model and compared to the measurements.
Thilina Jayarathne, Chelsea E. Stockwell, Prakash V. Bhave, Puppala S. Praveen, Chathurika M. Rathnayake, Md. Robiul Islam, Arnico K. Panday, Sagar Adhikari, Rashmi Maharjan, J. Douglas Goetz, Peter F. DeCarlo, Eri Saikawa, Robert J. Yokelson, and Elizabeth A. Stone
Atmos. Chem. Phys., 18, 2259–2286,Short summary
Emissions of fine particulate matter and its constituents were quantified for a variety of under-sampled combustion sources in South Asia: wood and dung cooking fires, generators, groundwater pumps, brick kilns, trash burning, and open burning of biomasses. Garbage burning and three-stone cooking fires were among the highest emitters, while servicing of motor vehicles significantly reduced PM. These data may be used in source apportionment and to update regional and global emission inventories.
Sangeeta Sharma, W. Richard Leaitch, Lin Huang, Daniel Veber, Felicia Kolonjari, Wendy Zhang, Sarah J. Hanna, Allan K. Bertram, and John A. Ogren
Atmos. Chem. Phys., 17, 15225–15243,Short summary
A new and unique data set on BC properties at the highest latitude observatory in the world, at Alert, Canada, evaluates three techniques for estimating black carbon (BC) and gives seasonal best estimates of the BC mass concentrations and BC mass absorption coefficients (MAC) for 2.5 years of data. As a short-lived climate forcer, better estimates of the properties of BC are necessary to ensure accurate modelling of aerosol climate forcing of the Arctic atmosphere for mitigation purposes.
John Backman, Lauren Schmeisser, Aki Virkkula, John A. Ogren, Eija Asmi, Sandra Starkweather, Sangeeta Sharma, Konstantinos Eleftheriadis, Taneil Uttal, Anne Jefferson, Michael Bergin, Alexander Makshtas, Peter Tunved, and Markus Fiebig
Atmos. Meas. Tech., 10, 5039–5062,Short summary
Light absorption by aerosol particles is of climatic importance. A widely used means to measure aerosol light absorption is a filter-based measurement technique. In remote areas, such as the Arctic, filter-based instruments operate close to their detection limit. The study presents how a lower detection limit can be achieved for one such instrument, the Aethalometer. Additionally, the Aethalometer is compared to similar instruments, thus improving measurement inter-comparability in the Arctic.
John A. Ogren, Jim Wendell, Elisabeth Andrews, and Patrick J. Sheridan
Atmos. Meas. Tech., 10, 4805–4818,Short summary
A new photometer for continuous measurements of aerosol light absorption coefficient is described, optimized for long-term studies of the climate-forcing properties of aerosols. The device is small, sensitive, precise, and simple to operate. It is suitable for long-term measurements at remote locations and is currently in operation at about two dozen sites worldwide.
Chaeyoon Cho, Sang-Woo Kim, Maheswar Rupakheti, Jin-Soo Park, Arnico Panday, Soon-Chang Yoon, Ji-Hyoung Kim, Hyunjae Kim, Haeun Jeon, Minyoung Sung, Bong Mann Kim, Seungkyu K. Hong, Rokjin J. Park, Dipesh Rupakheti, Khadak Singh Mahata, Puppala Siva Praveen, Mark G. Lawrence, and Brent Holben
Atmos. Chem. Phys., 17, 12617–12632,Short summary
We investigated the optical and chemical properties and direct radiative effects of aerosols in the Kathmandu Valley. We concluded that the ratio of light-absorbing to scattering aerosols as well as the concentration of light-absorbing aerosols is much higher at Kathmandu than other comparable regions, and it contributes to a great atmospheric absorption efficiency. This study provides unprecedented insights into aerosol optical properties and their radiative forcings in the Kathmandu Valley.
Lauren Schmeisser, Elisabeth Andrews, John A. Ogren, Patrick Sheridan, Anne Jefferson, Sangeeta Sharma, Jeong Eun Kim, James P. Sherman, Mar Sorribas, Ivo Kalapov, Todor Arsov, Christo Angelov, Olga L. Mayol-Bracero, Casper Labuschagne, Sang-Woo Kim, András Hoffer, Neng-Huei Lin, Hao-Ping Chia, Michael Bergin, Junying Sun, Peng Liu, and Hao Wu
Atmos. Chem. Phys., 17, 12097–12120,Short summary
Three methods are used to classify aerosol type from aerosol optical properties measured in situ at 24 surface sites. Classification methods work best at sites with stable, homogenous aerosol at particularly polluted and dust-prone continental and marine sites. Classification methods are poor at remote marine and Arctic sites. Using these methods to extrapolate aerosol type from optical properties can help determine aerosol radiative forcing and improve aerosol satellite retrieval algorithms.
Dipesh Rupakheti, Bhupesh Adhikary, Puppala Siva Praveen, Maheswar Rupakheti, Shichang Kang, Khadak Singh Mahata, Manish Naja, Qianggong Zhang, Arnico Kumar Panday, and Mark G. Lawrence
Atmos. Chem. Phys., 17, 11041–11063,Short summary
For the first time, atmospheric composition was monitored during pre-monsoon season of 2013 at Lumbini (UNESCO world heritage site as birthplace of the Buddha). PM and O3 frequently exceeded WHO guidelines. Pollution concentration, diurnal characteristics and influence of open burning on air quality in Lumbini were investigated. Potential source regions were also identified. Results show that air pollution at this site is of a great concern, requiring prompt attention for mitigation.
Héctor Rivera, John A. Ogren, Elisabeth Andrews, and Olga L. Mayol-Bracero
Atmos. Chem. Phys. Discuss.,
Preprint withdrawnShort summary
To lower the climate uncertainty by aerosols, we evaluated the radiative-forcing properties of aerosols in Puerto Rico analyzing their means and variability vs. amount, sizes, and light absorbing properties. Mean amounts, sizes, and absorbing properties differed among aerosol classes in the marine boundary layer and atmospheric column. Coarse African dust produced 50 % more cooling at the top of the atmosphere and temperature changes 50 % greater than volcanic ash within the marine boundary layer.
Lena Frey, Frida A.-M. Bender, and Gunilla Svensson
Atmos. Chem. Phys., 17, 9145–9162,Short summary
In this study, the cloud albedo effect in climate models is investigated, separating the influence of anthropogenic sulfate and non-sulfate aerosols. Cloud albedo changes induced by added anthropogenic aerosols are found to be determined by changes in the cloud water content rather than model sensitivity to monthly aerosol variations. The results also indicate that the background aerosol is the main driver for a cloud brightening effect on the month-to-month scale.
Katharina Loewe, Annica M. L. Ekman, Marco Paukert, Joseph Sedlar, Michael Tjernström, and Corinna Hoose
Atmos. Chem. Phys., 17, 6693–6704,Short summary
Processes that affect Arctic mixed-phase cloud life cycle are extremely important for the surface energy budget. Three different sensitivity experiments mimic changes in the advection of air masses with different thermodynamic profiles and aerosol properties to find the potential mechanisms leading to the dissipation of the cloud. We found that the reduction of the cloud droplet number concentration was likely the primary contributor to the dissipation of the observed Arctic mixed-phase cloud.
Kabindra M. Shakya, Maheswar Rupakheti, Anima Shahi, Rejina Maskey, Bidya Pradhan, Arnico Panday, Siva P. Puppala, Mark Lawrence, and Richard E. Peltier
Atmos. Chem. Phys., 17, 6503–6516,Short summary
Particulate matter levels were monitored at six major roadway intersections in the Kathmandu Valley during two seasons in 2014. The study documented distinct seasonal (dry season versus wet season) and diel variations in particulate matter levels. This study suggests traffic-related emissions, and soil–dust–construction materials were found to be a major source of particulate matter at these locations.
Elisabeth Andrews, John A. Ogren, Stefan Kinne, and Bjorn Samset
Atmos. Chem. Phys., 17, 6041–6072,Short summary
We compare absorption aerosol optical depth (AAOD) and single scattering albedo (SSA) from AERONET retrievals with AAOD and SSA obtained from in situ vertical profiling flights over two rural sites in North America. The direct comparisons of in situ derived to AERONET-retrieved AAOD (or SSA) reveal that AERONET retrievals yield higher aerosol absorption than obtained from the in situ profiles. This has implications for models using AERONET to evaluate or scale their simulated absorption values.
Sujan Shrestha, Siva Praveen Puppala, Bhupesh Adhikary, Kundan Lal Shrestha, and Arnico K. Panday
Atmos. Chem. Phys. Discuss.,
Revised manuscript not accepted
Chelsea E. Stockwell, Ted J. Christian, J. Douglas Goetz, Thilina Jayarathne, Prakash V. Bhave, Puppala S. Praveen, Sagar Adhikari, Rashmi Maharjan, Peter F. DeCarlo, Elizabeth A. Stone, Eri Saikawa, Donald R. Blake, Isobel J. Simpson, Robert J. Yokelson, and Arnico K. Panday
Atmos. Chem. Phys., 16, 11043–11081,Short summary
We present the first, or rare, field measurements in South Asia of emission factors for up to 80 gases (pollutants, greenhouse gases, and precursors) and black carbon and aerosol optical properties at 405 and 870 nm for many previously under-sampled sources that are important in developing countries such as cooking with dung and wood, garbage and crop residue burning, brick kilns, motorcycles, generators and pumps, etc. Brown carbon contributes significantly to total aerosol absorption.
Kristina Pistone, Puppala S. Praveen, Rick M. Thomas, Veerabhadran Ramanathan, Eric M. Wilcox, and Frida A.-M. Bender
Atmos. Chem. Phys., 16, 5203–5227,Short summary
A recent field campaign (CARDEX) in the northern Indian Ocean concurrently measured cloud and aerosol properties and atmospheric structure and dynamics from a ground-based observatory and unmanned aerial vehicles (UAVs). These new measurements show a correlation between highly polluted conditions and increased cloud water content, concurrent with higher atmospheric temperature and humidity. Such correlations may be of interest in future studies of the effects of pollution on cloud properties.
Y. Xu, V. Ramanathan, and W. M. Washington
Atmos. Chem. Phys., 16, 1303–1315,Short summary
We show that black carbon aerosol pollution is likely the dominant factor in causing the accelerated retreat of snowpack in Himalayas. The simulated snow fraction and surface albedo change at the surface, as well as the enhanced warming at higher elevations, are remarkably similar to observations in past decades. The reason for the model's ability to simulate the observed trends is that we replace the model-simulated black carbon forcing with one that is constrained by observations.
E. W. Butt, A. Rap, A. Schmidt, C. E. Scott, K. J. Pringle, C. L. Reddington, N. A. D. Richards, M. T. Woodhouse, J. Ramirez-Villegas, H. Yang, V. Vakkari, E. A. Stone, M. Rupakheti, P. S. Praveen, P. G. van Zyl, J. P. Beukes, M. Josipovic, E. J. S. Mitchell, S. M. Sallu, P. M. Forster, and D. V. Spracklen
Atmos. Chem. Phys., 16, 873–905,Short summary
We estimate the impact of residential emissions (cooking and heating) on atmospheric aerosol, human health, and climate. We find large contributions to annual mean ambient PM2.5 in residential sources regions resulting in significant but uncertain global premature mortality when key uncertainties in emission flux are considered. We show that residential emissions exert an uncertain global radiative effect and suggest more work is needed to characterise residential emissions climate importance.
A. G. Hallar, R. Petersen, E. Andrews, J. Michalsky, I. B. McCubbin, and J. A. Ogren
Atmos. Chem. Phys., 15, 13665–13679,Short summary
The atmospheric seasonal impact of dust and biomass burning is considered for the western United States from 1999 to 2014. Median contributions to spring and summer aerosol optical depth (AOD) from dust and biomass-burning aerosols are comparable, with more frequent and short duration high AOD measurements due to biomass-burning episodes in summer than in spring. This data set highlights the wide scale implications of a warmer, drier climate on visibility in the western US.
J. P. Sherman, P. J. Sheridan, J. A. Ogren, E. Andrews, D. Hageman, L. Schmeisser, A. Jefferson, and S. Sharma
Atmos. Chem. Phys., 15, 12487–12517,Short summary
Variability in aerosol optical properties relevant to radiative forcing were studied on several timescales at four continental North American NOAA-ESRL sites. Light scattering and intensive properties varied most on seasonal scales while absorption variability on weekly and diurnal timescales was comparable to its seasonal variability. Large reductions in light scattering were observed at the two long-term sites (relative to late 1990s), along with a smaller contribution by sub-1µm particles.
E. Johansson, A. Devasthale, T. L'Ecuyer, A. M. L. Ekman, and M. Tjernström
Atmos. Chem. Phys., 15, 11557–11570,Short summary
Both radiative and latent heat components of total diabatic heating influence Indian monsoon dynamics. This study investigates radiative component in detail, focusing on various cloud types that have largest radiative impact during summer monsoon over the Indian subcontinent. The vertical structure of radiative heating and its intra-seasonal variability is investigated with particular emphasis on the upper troposphere and lower stratosphere (UTLS) region.
X. Feng, Ö. Gustafsson, R. M. Holmes, J. E. Vonk, B. E. van Dongen, I. P. Semiletov, O. V. Dudarev, M. B. Yunker, R. W. Macdonald, D. B. Montluçon, and T. I. Eglinton
Biogeosciences, 12, 4841–4860,Short summary
Currently very few studies have examined the distribution and fate of hydrolyzable organic carbon (OC) in Arctic sediments, whose fate remains unclear in the context of climate change. Our study focuses on the source, distribution and fate of hydrolyzable OC as compared with plant wax lipids and lignin phenols in the sedimentary particles of nine Arctic and sub-Arctic rivers. This multi-molecular approach allows for a comprehensive investigation of terrestrial OC transfer via Arctic rivers.
L. Zhang, J. Y. Sun, X. J. Shen, Y. M. Zhang, H. Che, Q. L. Ma, Y. W. Zhang, X. Y. Zhang, and J. A. Ogren
Atmos. Chem. Phys., 15, 8439–8454,Short summary
The aerosol hygroscopic properties at a rural background site in the Yangtze River delta of China was discussed. The results show the scattering coefficient and backscattering coefficient increased by 58 and 25% as relative humidity (RH) increased from 40 to 85%, while the hemispheric backscatter fraction decreased by 21%. Aerosol hygroscopic growth caused a 47% increase in calculated aerosol direct radiative forcing at 85% RH compared to the forcing at 40% RH. Nitrate played a vital role.
T. Müller, A. Virkkula, and J. A. Ogren
Atmos. Meas. Tech., 7, 4049–4070,
N. Rastak, S. Silvergren, P. Zieger, U. Wideqvist, J. Ström, B. Svenningsson, M. Maturilli, M. Tesche, A. M. L. Ekman, P. Tunved, and I. Riipinen
Atmos. Chem. Phys., 14, 7445–7460,
G. Titos, A. Jefferson, P. J. Sheridan, E. Andrews, H. Lyamani, L. Alados-Arboledas, and J. A. Ogren
Atmos. Chem. Phys., 14, 7031–7043,
G. W. Mann, K. S. Carslaw, C. L. Reddington, K. J. Pringle, M. Schulz, A. Asmi, D. V. Spracklen, D. A. Ridley, M. T. Woodhouse, L. A. Lee, K. Zhang, S. J. Ghan, R. C. Easter, X. Liu, P. Stier, Y. H. Lee, P. J. Adams, H. Tost, J. Lelieveld, S. E. Bauer, K. Tsigaridis, T. P. C. van Noije, A. Strunk, E. Vignati, N. Bellouin, M. Dalvi, C. E. Johnson, T. Bergman, H. Kokkola, K. von Salzen, F. Yu, G. Luo, A. Petzold, J. Heintzenberg, A. Clarke, J. A. Ogren, J. Gras, U. Baltensperger, U. Kaminski, S. G. Jennings, C. D. O'Dowd, R. M. Harrison, D. C. S. Beddows, M. Kulmala, Y. Viisanen, V. Ulevicius, N. Mihalopoulos, V. Zdimal, M. Fiebig, H.-C. Hansson, E. Swietlicki, and J. S. Henzing
Atmos. Chem. Phys., 14, 4679–4713,
M. Fiebig, D. Hirdman, C. R. Lunder, J. A. Ogren, S. Solberg, A. Stohl, and R. L. Thompson
Atmos. Chem. Phys., 14, 3083–3093,
C. Wesslén, M. Tjernström, D. H. Bromwich, G. de Boer, A. M. L. Ekman, L.-S. Bai, and S.-H. Wang
Atmos. Chem. Phys., 14, 2605–2624,
A. Cazorla, R. Bahadur, K. J. Suski, J. F. Cahill, D. Chand, B. Schmid, V. Ramanathan, and K. A. Prather
Atmos. Chem. Phys., 13, 9337–9350,
Y. Feng, V. Ramanathan, and V. R. Kotamarthi
Atmos. Chem. Phys., 13, 8607–8621,
A. Petzold, J. A. Ogren, M. Fiebig, P. Laj, S.-M. Li, U. Baltensperger, T. Holzer-Popp, S. Kinne, G. Pappalardo, N. Sugimoto, C. Wehrli, A. Wiedensohler, and X.-Y. Zhang
Atmos. Chem. Phys., 13, 8365–8379,
Y. Xu, D. Zaelke, G. J. M. Velders, and V. Ramanathan
Atmos. Chem. Phys., 13, 6083–6089,
J. Zábori, R. Krejci, J. Ström, P. Vaattovaara, A. M. L. Ekman, M. E. Salter, E. M. Mårtensson, and E. D. Nilsson
Atmos. Chem. Phys., 13, 4783–4799,
A. Kirkevåg, T. Iversen, Ø. Seland, C. Hoose, J. E. Kristjánsson, H. Struthers, A. M. L. Ekman, S. Ghan, J. Griesfeller, E. D. Nilsson, and M. Schulz
Geosci. Model Dev., 6, 207–244,
M. Collaud Coen, E. Andrews, A. Asmi, U. Baltensperger, N. Bukowiecki, D. Day, M. Fiebig, A. M. Fjaeraa, H. Flentje, A. Hyvärinen, A. Jefferson, S. G. Jennings, G. Kouvarakis, H. Lihavainen, C. Lund Myhre, W. C. Malm, N. Mihapopoulos, J. V. Molenar, C. O'Dowd, J. A. Ogren, B. A. Schichtel, P. Sheridan, A. Virkkula, E. Weingartner, R. Weller, and P. Laj
Atmos. Chem. Phys., 13, 869–894,
A. Asmi, M. Collaud Coen, J. A. Ogren, E. Andrews, P. Sheridan, A. Jefferson, E. Weingartner, U. Baltensperger, N. Bukowiecki, H. Lihavainen, N. Kivekäs, E. Asmi, P. P. Aalto, M. Kulmala, A. Wiedensohler, W. Birmili, A. Hamed, C. O'Dowd, S. G Jennings, R. Weller, H. Flentje, A. M. Fjaeraa, M. Fiebig, C. L. Myhre, A. G. Hallar, E. Swietlicki, A. Kristensson, and P. Laj
Atmos. Chem. Phys., 13, 895–916,
P. J. Sheridan, E. Andrews, J. A. Ogren, J. L. Tackett, and D. M. Winker
Atmos. Chem. Phys., 12, 11695–11721,
Related subject area
Subject: Aerosols | Research Activity: Field Measurements | Altitude Range: Troposphere | Science Focus: Physics (physical properties and processes)Controls on surface aerosol particle number concentrations and aerosol-limited cloud regimes over the central Greenland Ice SheetAmbient aerosol properties in the remote atmosphere from global-scale in situ measurementsResponse of particle number concentrations to the clean air action plan: lessons from the first long-term aerosol measurements in a typical urban valley in western ChinaObservations of supermicron-sized aerosols originating from biomass burning in southern Central AfricaIce-nucleating particle concentration measurements from Ny-Ålesund during the Arctic spring–summer in 2018Clustering diurnal cycles of day-to-day temperature change to understand their impacts on air quality forecasting in mountain-basin areasEvaluation of the contribution of new particle formation to cloud droplet number concentration in the urban atmosphereA global study of hygroscopicity-driven light-scattering enhancement in the context of other in situ aerosol optical propertiesOptical properties of coated black carbon aggregates: numerical simulations, radiative forcing estimates, and size-resolved parameterization schemeMeasurement report: Cloud condensation nuclei activity and its variation with organic oxidation level and volatility observed during an aerosol life cycle intensive operational period (ALC-IOP)Southern Ocean latitudinal gradients of cloud condensation nucleiZeppelin-led study on the onset of new particle formation in the planetary boundary layerCharacterization of aerosol number size distributions and their effect on cloud properties at Syowa Station, AntarcticaA phenomenology of new particle formation (NPF) at 13 European sitesDiel cycle impacts on the chemical and light absorption properties of organic carbon aerosol from wildfires in the western United StatesTerrestrial or marine – indications towards the origin of ice-nucleating particles during melt season in the European Arctic up to 83.7° NCloud activation properties of aerosol particles in a continental Central European urban environmentVertical profiles of trace gas and aerosol properties over the eastern North Atlantic: variations with season and synoptic conditionOn the drivers of droplet variability in alpine mixed-phase cloudsContrasting effects of secondary organic aerosol formations on organic aerosol hygroscopicityImpact of aerosol–radiation interaction on new particle formationMeasurement report: The effect of aerosol chemical composition on light scattering due to the hygroscopic swelling effectMeasurement report: The influence of traffic and new particle formation on the size distribution of 1–800 nm particles in Helsinki – a street canyon and an urban background station comparisonSummer aerosol measurements over the East Antarctic seasonal ice zoneAerosol Responses to Precipitation Along North American Air Trajectories Arriving at BermudaRapid transformation of ambient absorbing aerosols from West African biomass burningTechnical note: Sea salt interference with black carbon quantification in snow samples using the single particle soot photometerMixing state of refractory black carbon aerosol in the South Asian outflow over the northern Indian Ocean during winterTowards understanding the characteristics of new particle formation in the Eastern MediterraneanLarge-scale synoptic drivers of co-occurring summertime ozone and PM2.5 pollution in eastern ChinaA long-term study of cloud residuals from low-level Arctic cloudsMeasurement report: Altitudinal variation of cloud condensation nuclei activation across the Indo-Gangetic Plain prior to monsoon onset and during peak monsoon periods: results from the SWAAMI field campaignUrban aerosol size distributions: a global perspectiveThe impact of aerosol size-dependent hygroscopicity and mixing state on the cloud condensation nuclei potential over the north-east AtlanticMeasurement report: Strong light absorption induced by aged biomass burning black carbon over the southeastern Tibetan Plateau in pre-monsoon seasonThe important roles of surface tension and growth rate in the contribution of new particle formation (NPF) to cloud condensation nuclei (CCN) number concentration: evidence from field measurements in southern ChinaAerosol particle formation in the upper residual layerSecondary aerosol formation alters CCN activity in the North China PlainComplex refractive indices in the ultraviolet and visible spectral region for highly absorbing non-spherical biomass burning aerosolDilution impacts on smoke aging: evidence in Biomass Burning Observation Project (BBOP) dataMeasurement report: Balloon-borne in situ profiling of Saharan dust over Cyprus with the UCASS optical particle counterArctic black carbon during PAMARCMiP 2018 and previous aircraft experiments in springEl Niño–Southern Oscillation (ENSO) effect on interannual variability in spring aerosols over East AsiaThe impact threshold of the aerosol radiative forcing on the boundary layer structure in the pollution regionTechnical note: Measurement of chemically resolved volume equivalent diameter and effective density of particles by AAC-SPAMSA meteorological overview of the ORACLES (ObseRvations of Aerosols above CLouds and their intEractionS) campaign over the southeast Atlantic during 2016–2018The impact of cloudiness and cloud type on the atmospheric heating rate of black and brown carbon in the Po ValleyMeteorology-driven variability of air pollution (PM1) revealed with explainable machine learningThe seasonal cycle of ice-nucleating particles linked to the abundance of biogenic aerosol in boreal forestsMeasurement report: Cloud processes and the transport of biological emissions affect southern ocean particle and cloud condensation nuclei concentrations
Heather Guy, Ian M. Brooks, Ken S. Carslaw, Benjamin J. Murray, Von P. Walden, Matthew D. Shupe, Claire Pettersen, David D. Turner, Christopher J. Cox, William D. Neff, Ralf Bennartz, and Ryan R. Neely III
Atmos. Chem. Phys., 21, 15351–15374,Short summary
We present the first full year of surface aerosol number concentration measurements from the central Greenland Ice Sheet. Aerosol concentrations here have a distinct seasonal cycle from those at lower-altitude Arctic sites, which is driven by large-scale atmospheric circulation. Our results can be used to help understand the role aerosols might play in Greenland surface melt through the modification of cloud properties. This is crucial in a rapidly changing region where observations are sparse.
Charles A. Brock, Karl D. Froyd, Maximilian Dollner, Christina J. Williamson, Gregory Schill, Daniel M. Murphy, Nicholas J. Wagner, Agnieszka Kupc, Jose L. Jimenez, Pedro Campuzano-Jost, Benjamin A. Nault, Jason C. Schroder, Douglas A. Day, Derek J. Price, Bernadett Weinzierl, Joshua P. Schwarz, Joseph M. Katich, Siyuan Wang, Linghan Zeng, Rodney Weber, Jack Dibb, Eric Scheuer, Glenn S. Diskin, Joshua P. DiGangi, ThaoPaul Bui, Jonathan M. Dean-Day, Chelsea R. Thompson, Jeff Peischl, Thomas B. Ryerson, Ilann Bourgeois, Bruce C. Daube, Róisín Commane, and Steven C. Wofsy
Atmos. Chem. Phys., 21, 15023–15063,Short summary
The Atmospheric Tomography Mission was an airborne study that mapped the chemical composition of the remote atmosphere. From this, we developed a comprehensive description of aerosol properties that provides a unique, global-scale dataset against which models can be compared. The data show the polluted nature of the remote atmosphere in the Northern Hemisphere and quantify the contributions of sea salt, dust, soot, biomass burning particles, and pollution particles to the haziness of the sky.
Suping Zhao, Ye Yu, Jianglin Li, Daiying Yin, Shaofeng Qi, and Dahe Qin
Atmos. Chem. Phys., 21, 14959–14981,Short summary
We found a large PM2.5 reduction in response to Clean Air Action (CAA), but impacts of CAA on particle number concentrations (PNCs) may be different from PM2.5 mass due to newly formed particle impacts. The k-means clustering technique and Theil–Sen regression were used to analyze PNCs variations and to quantify their trends. Increased daytime solar radiation, higher temperature and lower RH at noon induced by reduced PM2.5 mass promoted formation of new particles and increased particle numbers.
Rose M. Miller, Greg M. McFarquhar, Robert M. Rauber, Joseph R. O'Brien, Siddhant Gupta, Michal Segal-Rozenhaimer, Amie N. Dobracki, Arthur J. Sedlacek, Sharon P. Burton, Steven G. Howell, Steffen Freitag, and Caroline Dang
Atmos. Chem. Phys., 21, 14815–14831,Short summary
A large stratocumulus cloud deck resides off the west coast of central Africa. Biomass burning in Africa produces a large plume of aerosol that is carried by the wind over this stratocumulus cloud deck. This paper shows that particles with sizes from 0.01 to 1 mm reside within this plume. Past studies have shown that biomass burning produces such particles, but this is the first study to show that they can be transported westward, over long distances, to the Atlantic stratocumulus cloud deck.
Matteo Rinaldi, Naruki Hiranuma, Gianni Santachiara, Mauro Mazzola, Karam Mansour, Marco Paglione, Cheyanne A. Rodriguez, Rita Traversi, Silvia Becagli, David Cappelletti, and Franco Belosi
Atmos. Chem. Phys., 21, 14725–14748,Short summary
This study aims to add to the still scant ice-nucleating particle (INP) observations in the Arctic environment, investigating INP concentrations and potential sources, during spring and summertime, at the ground-level site of GVB. The lack of a clear concentration seasonal trend, in contrast with previous works, shows an important interannual variability of Arctic INP sources, which may be both terrestrial and marine, outside the Arctic haze period.
Debing Kong, Guicai Ning, Shigong Wang, Jing Cong, Ming Luo, Xiang Ni, and Mingguo Ma
Atmos. Chem. Phys., 21, 14493–14505,Short summary
This study provides the first attempt to examine the diurnal cycles of day-to-day temperature change and reveals their impacts on air quality forecasting in mountain-basin areas. Three different diurnal cycles of the preceding day-to-day temperature change are identified and exhibit notably distinct effects on the air quality evolutions. The mechanisms of the identified diurnal cycles' effects on air quality are also revealed, which exhibit promising potential for air quality forecasting.
Sihui Jiang, Fang Zhang, Jingye Ren, Lu Chen, Xing Yan, Jieyao Liu, Yele Sun, and Zhanqing Li
Atmos. Chem. Phys., 21, 14293–14308,Short summary
New particle formation (NPF) can be a large source of CCN and affect weather and climate. Here we show that the NPF contributes largely to cloud droplet number concentration (Nd) but is suppressed at high particle number concentrations in Beijing due to water vapor competition. We also reveal a considerable impact of primary sources on the evaluation in the urban atmosphere. Our study has great significance for assessing NPF-associated effects on climate in polluted regions.
Gloria Titos, María A. Burgos, Paul Zieger, Lucas Alados-Arboledas, Urs Baltensperger, Anne Jefferson, James Sherman, Ernest Weingartner, Bas Henzing, Krista Luoma, Colin O'Dowd, Alfred Wiedensohler, and Elisabeth Andrews
Atmos. Chem. Phys., 21, 13031–13050,Short summary
This paper investigates the impact of water uptake on aerosol optical properties, in particular the aerosol light-scattering coefficient. Although in situ measurements are performed at low relative humidity (typically at RH < 40 %), to address the climatic impact of aerosol particles it is necessary to take into account the effect that water uptake may have on the aerosol optical properties.
Baseerat Romshoo, Thomas Müller, Sascha Pfeifer, Jorge Saturno, Andreas Nowak, Krzysztof Ciupek, Paul Quincey, and Alfred Wiedensohler
Atmos. Chem. Phys., 21, 12989–13010,Short summary
Modifications in the optical properties of black carbon (BC) due to ageing are presented and quantified in this study using a state-of-the-art description scheme of BC fractal aggregates. It is shown that the relative change in BC radiative forcing can be larger than 50 % as a function of changing fractal dimension and organic content. A comprehensive parameterization scheme for coated BC optical properties is developed with applications for modelling, ambient, and laboratory-based BC studies.
Fan Mei, Jian Wang, Shan Zhou, Qi Zhang, Sonya Collier, and Jianzhong Xu
Atmos. Chem. Phys., 21, 13019–13029,Short summary
This work focuses on understanding aerosol's ability to act as cloud condensation nuclei (CCN) and its variations with organic oxidation level and volatility using measurements at a rural site. Aerosol properties were examined from four air mass sources. The results help improve the accurate representation of aerosol from different ambient aerosol emissions, transformation pathways, and atmospheric processes in a climate model.
Ruhi S. Humphries, Melita D. Keywood, Sean Gribben, Ian M. McRobert, Jason P. Ward, Paul Selleck, Sally Taylor, James Harnwell, Connor Flynn, Gourihar R. Kulkarni, Gerald G. Mace, Alain Protat, Simon P. Alexander, and Greg McFarquhar
Atmos. Chem. Phys., 21, 12757–12782,Short summary
The Southern Ocean region is one of the most pristine in the world and serves as an important proxy for the pre-industrial atmosphere. Improving our understanding of the natural processes in this region is likely to result in the largest reductions in the uncertainty of climate and earth system models. In this paper we present a statistical summary of the latitudinal gradient of aerosol and cloud condensation nuclei concentrations obtained from five voyages spanning the Southern Ocean.
Janne Lampilahti, Hanna E. Manninen, Tuomo Nieminen, Sander Mirme, Mikael Ehn, Iida Pullinen, Katri Leino, Siegfried Schobesberger, Juha Kangasluoma, Jenni Kontkanen, Emma Järvinen, Riikka Väänänen, Taina Yli-Juuti, Radovan Krejci, Katrianne Lehtipalo, Janne Levula, Aadu Mirme, Stefano Decesari, Ralf Tillmann, Douglas R. Worsnop, Franz Rohrer, Astrid Kiendler-Scharr, Tuukka Petäjä, Veli-Matti Kerminen, Thomas F. Mentel, and Markku Kulmala
Atmos. Chem. Phys., 21, 12649–12663,Short summary
We studied aerosol particle formation and growth in different parts of the planetary boundary layer at two different locations (Po Valley, Italy, and Hyytiälä, Finland). The observations consist of airborne measurements on board an instrumented Zeppelin and a small airplane combined with comprehensive ground-based measurements.
Keiichiro Hara, Chiharu Nishita-Hara, Kazuo Osada, Masanori Yabuki, and Takashi Yamanouchi
Atmos. Chem. Phys., 21, 12155–12172,Short summary
New particle formation (NPF) occurred dominantly in the Antarctic free troposphere during spring and fall and in the free troposphere and boundary layer during summer. With the existence of the ozone hole, more UV radiation can enhance formation of aerosol precursors and NPF in the free troposphere. Here, we assess the hypothesis that UV enhancement in the upper troposphere by the Antarctic ozone hole modifies the aerosol and cloud properties in Antarctic regions during summer.
Dimitrios Bousiotis, Francis D. Pope, David C. S. Beddows, Manuel Dall'Osto, Andreas Massling, Jakob Klenø Nøjgaard, Claus Nordstrøm, Jarkko V. Niemi, Harri Portin, Tuukka Petäjä, Noemi Perez, Andrés Alastuey, Xavier Querol, Giorgos Kouvarakis, Nikos Mihalopoulos, Stergios Vratolis, Konstantinos Eleftheriadis, Alfred Wiedensohler, Kay Weinhold, Maik Merkel, Thomas Tuch, and Roy M. Harrison
Atmos. Chem. Phys., 21, 11905–11925,Short summary
Formation of new particles is a key process in the atmosphere. New particle formation events arising from nucleation of gaseous precursors have been analysed in extensive datasets from 13 sites in five European countries in terms of frequency, nucleation rate, and particle growth rate, with several common features and many differences identified. Although nucleation frequencies are lower at roadside sites, nucleation rates and particle growth rates are typically higher.
Benjamin Sumlin, Edward Fortner, Andrew Lambe, Nishit J. Shetty, Conner Daube, Pai Liu, Francesca Majluf, Scott Herndon, and Rajan K. Chakrabarty
Atmos. Chem. Phys., 21, 11843–11856,Short summary
We present a comparison of the changes to light absorption behavior and chemical composition of wildfire smoke particles from day- and nighttime oxidation processes and discuss the results within the context of previous laboratory findings.
Markus Hartmann, Xianda Gong, Simonas Kecorius, Manuela van Pinxteren, Teresa Vogl, André Welti, Heike Wex, Sebastian Zeppenfeld, Hartmut Herrmann, Alfred Wiedensohler, and Frank Stratmann
Atmos. Chem. Phys., 21, 11613–11636,Short summary
Ice-nucleating particles (INPs) are not well characterized in the Arctic despite their importance for the Arctic energy budget. Little is known about their nature (mineral or biological) and sources (terrestrial or marine, long-range transport or local). We find indications that, at the beginning of the melt season, a local, biogenic, probably marine source is likely, but significant enrichment of INPs has to take place from the ocean to the aerosol phase.
Imre Salma, Wanda Thén, Máté Vörösmarty, and András Zénó Gyöngyösi
Atmos. Chem. Phys., 21, 11289–11302,Short summary
Cloud condensation nuclei (CCN) and their properties were explored in this study. CCN modify the intensity and other properties of the sunlight reaching the Earth’s surface. These properties are primarily influenced by the number of droplets, the droplet size and the cloud residence time. CCN also influence the hydrological cycle (including the amount and intensity of precipitation), vegetation and its interactions with the carbon cycle, as well as atmospheric chemistry, physics and dynamics.
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,Short summary
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.
Paraskevi Georgakaki, Aikaterini Bougiatioti, Jörg Wieder, Claudia Mignani, Fabiola Ramelli, Zamin A. Kanji, Jan Henneberger, Maxime Hervo, Alexis Berne, Ulrike Lohmann, and Athanasios Nenes
Atmos. Chem. Phys., 21, 10993–11012,Short summary
Aerosol and cloud observations coupled with a droplet activation parameterization was used to investigate the aerosol–cloud droplet link in alpine mixed-phase clouds. Predicted droplet number, Nd, agrees with observations and never exceeds a characteristic “limiting droplet number”, Ndlim, which depends solely on σw. Nd becomes velocity limited when it is within 50 % of Ndlim. Identifying when dynamical changes control Nd variability is central for understanding aerosol–cloud interactions.
Ye Kuang, Shan Huang, Biao Xue, Biao Luo, Qicong Song, Wei Chen, Weiwei Hu, Wei Li, Pusheng Zhao, Mingfu Cai, Yuwen Peng, Jipeng Qi, Tiange Li, Sihang Wang, Duohong Chen, Dingli Yue, Bin Yuan, and Min Shao
Atmos. Chem. Phys., 21, 10375–10391,Short summary
We found that organic aerosol factors with identified sources perform much better than oxidation level parameters in characterizing variations in organic aerosol hygroscopicity, and secondary aerosol formations associated with different sources have distinct effects on organic aerosol hygroscopicity. It reveals that source-oriented organic aerosol hygroscopicity investigations might result in more appropriate parameterization approaches in chemical and climate models.
Gang Zhao, Yishu Zhu, Zhijun Wu, Taomou Zong, Jingchuan Chen, Tianyi Tan, Haichao Wang, Xin Fang, Keding Lu, Chunsheng Zhao, and Min Hu
Atmos. Chem. Phys., 21, 9995–10004,Short summary
New particle formation is thought to contribute half of the global cloud condensation nuclei. We find that the new particle formation is more likely to happen in the upper boundary layer than that at the ground, which can be partially explained by the aerosol–radiation interaction. Our study emphasizes the influence of aerosol–radiation interaction on the NPF.
Rongmin Ren, Zhanqing Li, Peng Yan, Yuying Wang, Hao Wu, Maureen Cribb, Wei Wang, Xiao'ai Jin, Yanan Li, and Dongmei Zhang
Atmos. Chem. Phys., 21, 9977–9994,Short summary
We analyzed the effect of the proportion of components making up the chemical composition of aerosols on f(RH) in southern Beijing in 2019. Nitrate played a more significant role in affecting f(RH) than sulfate. The ratio of the sulfate mass fraction to the nitrate mass fraction (mostly higher than ~ 4) was a sign of the deliquescence of aerosol. A piecewise parameterized scheme was proposed, which could better describe deliquescence and reduce uncertainties in simulating aerosol hygroscopicity.
Magdalena Okuljar, Heino Kuuluvainen, Jenni Kontkanen, Olga Garmash, Miska Olin, Jarkko V. Niemi, Hilkka Timonen, Juha Kangasluoma, Yee Jun Tham, Rima Baalbaki, Mikko Sipilä, Laura Salo, Henna Lintusaari, Harri Portin, Kimmo Teinilä, Minna Aurela, Miikka Dal Maso, Topi Rönkkö, Tuukka Petäjä, and Pauli Paasonen
Atmos. Chem. Phys., 21, 9931–9953,Short summary
To estimate the relative contribution of different sources to the particle population in an urban environment, we conducted simultaneous measurements at a street canyon and an urban background station in Helsinki. We investigated the contribution of traffic and new particle formation to particles with a diameter between 1 and 800 nm. We found that during spring traffic does not dominate the particles smaller than 3 nm at either of the stations.
Jack B. Simmons, Ruhi S. Humphries, Stephen R. Wilson, Scott D. Chambers, Alastair G. Williams, Alan D. Griffiths, Ian M. McRobert, Jason P. Ward, Melita D. Keywood, and Sean Gribben
Atmos. Chem. Phys., 21, 9497–9513,Short summary
Aerosols have a climate forcing effect in the Earth's atmosphere. Few measurements exist of aerosols in the Southern Ocean, a region key to our understanding of this effect. In this study, aerosol measurements from a summer 2017 campaign in the East Antarctic seasonal ice zone are examined. Higher concentrations of aerosols were found in dry air with origins from above the Antarctic continent compared to other periods of the voyage.
Hossein Dadashazar, Majid Alipanah, Miguel Ricardo A. Hilario, Ewan Crosbie, Simon Kirschler, Hongyu Liu, Richard H. Moore, Andrew J. Peters, Amy Jo Scarino, Michael Shook, K. Lee Thornhill, Christiane Voigt, Hailong Wang, Edward Winstead, Bo Zhang, Luke Ziemba, and Armin Sorooshian
Atmos. Chem. Phys. Discuss.,
Revised manuscript accepted for ACPShort summary
This study investigates precipitation impacts on long-range transport of North American over the western North Atlantic Ocean (WNAO). Our results demonstrate that precipitation scavenging plays a significant role in modifying surface aerosol concentrations over the WNAO, especially in winter/spring months due to large-scale scavenging processes. This study highlights how precipitation impacts surface aerosol properties with relevance for other marine regions vulnerable to continental outflow.
Huihui Wu, Jonathan W. Taylor, Justin M. Langridge, Chenjie Yu, James D. Allan, Kate Szpek, Michael I. Cotterell, Paul I. Williams, Michael Flynn, Patrick Barker, Cathryn Fox, Grant Allen, James Lee, and Hugh Coe
Atmos. Chem. Phys., 21, 9417–9440,Short summary
Seasonal biomass burning over West Africa is a globally significant source of carbonaceous particles in the atmosphere, which have important climate impacts but are poorly constrained. We conducted in situ airborne measurements to investigate the evolution of smoke aerosol properties in this region. We observed absorption enhancement for both black carbon and brown carbon after emission, which provides new field results and constraints on aerosol parameterizations for future climate models.
Marco Zanatta, Andreas Herber, Zsófia Jurányi, Oliver Eppers, Johannes Schneider, and Joshua P. Schwarz
Atmos. Chem. Phys., 21, 9329–9342,Short summary
Saline snow samples were collected from the sea ice in the Fram Strait. Laboratory experiments revealed that sea salt can bias the quantification of black carbon with a laser-induced incandescence technique. The maximum underestimation was quantified to reach values of 80 %–90 %. This salt-induced interference is reported here for the first time and should be considered in future studies aiming to quantify black carbon in snow in marine environments.
Sobhan Kumar Kompalli, Surendran Nair Suresh Babu, Krishnaswamy Krishna Moorthy, Sreedharan Krishnakumari Satheesh, Mukunda Madhab Gogoi, Vijayakumar S. Nair, Venugopalan Nair Jayachandran, Dantong Liu, Michael J. Flynn, and Hugh Coe
Atmos. Chem. Phys., 21, 9173–9199,Short summary
The first observations of refractory black carbon aerosol size distributions and mixing state in South Asian outflow to the northern Indian Ocean were carried out as a part of the ICARB-2018 experiment during winter. Size distributions indicated mixed sources of BC particles in the outflow, which are thickly coated. The coating thickness of BC is controlled mainly by the availability of condensable species in the outflow.
Rima Baalbaki, Michael Pikridas, Tuija Jokinen, Tiia Laurila, Lubna Dada, Spyros Bezantakos, Lauri Ahonen, Kimmo Neitola, Anne Maisser, Elie Bimenyimana, Aliki Christodoulou, Florin Unga, Chrysanthos Savvides, Katrianne Lehtipalo, Juha Kangasluoma, George Biskos, Tuukka Petäjä, Veli-Matti Kerminen, Jean Sciare, and Markku Kulmala
Atmos. Chem. Phys., 21, 9223–9251,Short summary
This study investigates new particle formation (NPF) in the less represented region of the Mediterranean basin using 1-year measurements of aerosol particles down to ~ 1 nm in diameter. We report a high frequency of NPF and give examples of interesting NPF features. We quantify the strength of NPF events by calculating formation rates and growth rates. We further unveil the atmospheric conditions and variables considered important for the intra-monthly and inter-monthly occurrence of NPF.
Lian Zong, Yuanjian Yang, Meng Gao, Hong Wang, Peng Wang, Hongliang Zhang, Linlin Wang, Guicai Ning, Chao Liu, Yubin Li, and Zhiqiu Gao
Atmos. Chem. Phys., 21, 9105–9124,Short summary
In recent years, summer O3 pollution over eastern China has become more serious, and it is even the case that surface O3 and PM2.5 pollution can co-occur. However, the synoptic weather pattern (SWP) related to this compound pollution remains unclear. Regional PM2.5 and O3 compound pollution is characterized by various SWPs with different dominant factors. Our findings provide insights into the regional co-occurring high PM2.5 and O3 levels via the effects of certain meteorological factors.
Linn Karlsson, Radovan Krejci, Makoto Koike, Kerstin Ebell, and Paul Zieger
Atmos. Chem. Phys., 21, 8933–8959,Short summary
Aerosol–cloud interactions in the Arctic are poorly understood largely due to a lack of observational data. We present the first direct, long-term measurements of cloud residuals, i.e. the particles that remain when cloud droplets and ice crystals are dried. These detailed observations of cloud residuals cover more than 2 years, which is unique for the Arctic and globally. This work studies the size distributions of cloud residuals, their seasonality, and dependence on meteorology.
Mohanan R. Manoj, Sreedharan K. Satheesh, Krishnaswamy K. Moorthy, Jamie Trembath, and Hugh Coe
Atmos. Chem. Phys., 21, 8979–8997,Short summary
Vertical distributions of atmospheric aerosols across the Indo-Gangetic Plain (IGP) and their ability to form clouds have been studied based on airborne measurements during the SWAAMI field campaign. The ability of the aerosols to act as cloud-forming nuclei exhibited large spatial variation across the IGP and strong seasonality with increase in this ability with increase in altitude prior to the onset of monsoon and decrease with increase in altitude during the active phase of the monsoon.
Tianren Wu and Brandon E. Boor
Atmos. Chem. Phys., 21, 8883–8914,Short summary
Urban air pollution is a major global environmental health challenge. Establishing associations between exposure to urban aerosols and human health outcomes requires reliable aerosol measurements. Of particular importance are measurements of urban aerosol particle size distributions. This review critically analyzes global trends in urban aerosol particle size distributions in order to provide insights into air pollution in cities and guidance for the future for air quality monitoring networks.
Wei Xu, Kirsten N. Fossum, Jurgita Ovadnevaite, Chunshui Lin, Ru-Jin Huang, Colin O'Dowd, and Darius Ceburnis
Atmos. Chem. Phys., 21, 8655–8675,Short summary
Cloud condensation nuclei (CCN) are an important topic in atmospheric studies, especially for evaluating the climate impact of aerosol. Here in this study, CCN closure is studied by using chemical composition based on an aerosol mass spectrometer (AMS) and hygroscopicity growth measurements based on a humidified tandem differential mobility analyzer (HTDMA) at the Mace Head atmospheric research station.
Tianyi Tan, Min Hu, Zhuofei Du, Gang Zhao, Dongjie Shang, Jing Zheng, Yanhong Qin, Mengren Li, Yusheng Wu, Limin Zeng, Song Guo, and Zhijun Wu
Atmos. Chem. Phys., 21, 8499–8510,Short summary
Every year in the pre-monsoon season, the black carbon (BC) aerosols originated from biomass burning in southern Asia are easily transported to the Tibetan Plateau (TP) by the convenience of westerly wind. This study reveals that the BC aerosols in the aged biomass burning plumes strongly enhance the total light absorption over the TP, and the aging process during the long-range transport will further strengthen the radiative heating of those BC aerosols.
Mingfu Cai, Baoling Liang, Qibin Sun, Li Liu, Bin Yuan, Min Shao, Shan Huang, Yuwen Peng, Zelong Wang, Haobo Tan, Fei Li, Hanbin Xu, Duohong Chen, and Jun Zhao
Atmos. Chem. Phys., 21, 8575–8592,Short summary
This study investigated the contribution of new particle formation (NPF) events to the number concentration of cloud condensation nuclei (NCCN) and its controlling factors in the Pearl River Delta region. The results show that the surfactant effect can decrease the critical diameter and significantly increase the NCCN during the NPF event. In addition, the growth rate is founded to be the most important controlling factor that affects NCCN for growth of newly-formed particles to the CCN sizes.
Janne Lampilahti, Katri Leino, Antti Manninen, Pyry Poutanen, Anna Franck, Maija Peltola, Paula Hietala, Lisa Beck, Lubna Dada, Lauriane Quéléver, Ronja Öhrnberg, Ying Zhou, Madeleine Ekblom, Ville Vakkari, Sergej Zilitinkevich, Veli-Matti Kerminen, Tuukka Petäjä, and Markku Kulmala
Atmos. Chem. Phys., 21, 7901–7915,Short summary
Using airborne measurements we observed increased number concentrations of sub-25 nm particles in the upper residual layer. These particles may be entrained into the well-mixed boundary layer and observed at the surface. We attribute our observations to new particle formation in the topmost part of the residual layer.
Jiangchuan Tao, Ye Kuang, Nan Ma, Juan Hong, Yele Sun, Wanyun Xu, Yanyan Zhang, Yao He, Qingwei Luo, Linhong Xie, Hang Su, and Yafang Cheng
Atmos. Chem. Phys., 21, 7409–7427,Short summary
The mechanism of secondary aerosol (SA) formation can be affected by relative humidity (RH) and has different influences on the particle CCN activity under different RH conditions. In the North China Plain, we find different responses of CCN activity and enhancements of CCN number concentration to SA formation under different RH conditions. In addition, variations of aerosol mixing state due to SA formation contribute some of the largest uncertainties in predicting CCN number concentration.
Caroline C. Womack, Katherine M. Manfred, Nicholas L. Wagner, Gabriela Adler, Alessandro Franchin, Kara D. Lamb, Ann M. Middlebrook, Joshua P. Schwarz, Charles A. Brock, Steven S. Brown, and Rebecca A. Washenfelder
Atmos. Chem. Phys., 21, 7235–7252,Short summary
Microscopic particles interact with sunlight and affect the earth's climate in ways that are not fully understood. Aerosols from wildfire smoke present particular challenges due to their complexity in shape and composition. We demonstrate that we can experimentally measure aerosol optical properties for many types of smoke particles, using measurements of smoke from controlled burns, but that the method does not work well for smoke with high soot content.
Anna L. Hodshire, Emily Ramnarine, Ali Akherati, Matthew L. Alvarado, Delphine K. Farmer, Shantanu H. Jathar, Sonia M. Kreidenweis, Chantelle R. Lonsdale, Timothy B. Onasch, Stephen R. Springston, Jian Wang, Yang Wang, Lawrence I. Kleinman, Arthur J. Sedlacek III, and Jeffrey R. Pierce
Atmos. Chem. Phys., 21, 6839–6855,Short summary
Biomass burning emits particles and vapors that can impact both health and climate. Here, we investigate the role of dilution in the evolution of aerosol size and composition in observed US wildfire smoke plumes. Centers of plumes dilute more slowly than edges. We see differences in concentrations and composition between the centers and edges both in the first measurement and in subsequent measurements. Our findings support the hypothesis that plume dilution influences smoke aging.
Maria Kezoudi, Matthias Tesche, Helen Smith, Alexandra Tsekeri, Holger Baars, Maximilian Dollner, Víctor Estellés, Johannes Bühl, Bernadett Weinzierl, Zbigniew Ulanowski, Detlef Müller, and Vassilis Amiridis
Atmos. Chem. Phys., 21, 6781–6797,Short summary
Mineral dust concentrations in the diameter range from 0.4 to 14.0 μm were measured with the balloon-borne UCASS optical particle counter. Launches were coordinated with ground-based remote-sensing and airborne in situ measurements during a Saharan dust outbreak over Cyprus. Particle number concentrations reached 50 cm−3 for the diameter range 0.8–13.9 μm. Comparisons with aircraft data show reasonable agreement in magnitude and shape of the particle size distribution.
Sho Ohata, Makoto Koike, Atsushi Yoshida, Nobuhiro Moteki, Kouji Adachi, Naga Oshima, Hitoshi Matsui, Oliver Eppers, Heiko Bozem, Marco Zanatta, and Andreas B. Herber
Atmos. Chem. Phys. Discuss.,
Revised manuscript accepted for ACPShort summary
Vertical profiles of black carbon (BC) in the Arctic were measured during the PAMARCMiP aircraft-based experiment in spring 2018 and compared with those observed during previous aircraft campaigns in 2008, 2010, and 2015. Their differences were explained primarily by the year-to-year variation of biomass burning activities in northern high latitudes over Eurasia. Our observations provide bases to evaluate numerical model simulations that assess the BC radiative effects in the Arctic spring.
Anbao Zhu, Haiming Xu, Jiechun Deng, Jing Ma, and Shuhui Li
Atmos. Chem. Phys., 21, 5919–5933,
Dandan Zhao, Jinyuan Xin, Chongshui Gong, Jiannong Quan, Yuesi Wang, Guiqian Tang, Yongxiang Ma, Lindong Dai, Xiaoyan Wu, Guangjing Liu, and Yongjing Ma
Atmos. Chem. Phys., 21, 5739–5753,Short summary
The influence of aerosol radiative forcing (ARF) on the boundary layer structure is nonlinear. The threshold of the modification effects of ARF on the boundary layer structure was determined for the first time, highlighting that once ARF exceeded a certain value, the boundary layer would quickly stabilize and aggravate air pollution. This could provide useful information for relevant atmospheric-environment improvement measures and policies.
Long Peng, Lei Li, Guohua Zhang, Xubing Du, Xinming Wang, Ping'an Peng, Guoying Sheng, and Xinhui Bi
Atmos. Chem. Phys., 21, 5605–5613,Short summary
We build a novel system that utilizes an aerodynamic aerosol classifier (AAC) combined with a single-particle aerosol mass spectrometry (SPAMS) to simultaneously characterize the volume equivalent diameter (Dve), chemical compositions, and effective density (ρe) of individual particles in real time. A test of the AAC-SPAMS with both spherical and aspherical particles shows that the deviations between the measured and theoretical values are less than 6 %.
Ju-Mee Ryoo, Leonhard Pfister, Rei Ueyama, Paquita Zuidema, Robert Wood, Ian Chang, and Jens Redemann
Atmos. Chem. Phys. Discuss.,
Revised manuscript accepted for ACPShort summary
Meteorology influences the aerosol-cloud interaction. Thus, it is critical to understand the meteorological characteristics during the deployment to better interpret the airborne measurement. Furthermore, it is crucial to know how different they are compared to the climatological mean in various temporal and spatial scales. This paper provides a thorough overview of the meteorology reflecting the coupled land-ocean-atmosphere system and the representativeness of the deployment months.
Luca Ferrero, Asta Gregorič, Griša Močnik, Martin Rigler, Sergio Cogliati, Francesca Barnaba, Luca Di Liberto, Gian Paolo Gobbi, Niccolò Losi, and Ezio Bolzacchini
Atmos. Chem. Phys., 21, 4869–4897,Short summary
The work experimentally quantifies the impact of cloudiness and cloud type on the atmospheric heating rate of black and brown carbon. The most impacting clouds were stratocumulus, altostratus and stratus. Clouds caused a decrease of the heating rate of about 12 % per okta. The black carbon decease was slightly higher with respect to that of brown carbon. This study highlights the need to take into account the role of cloudiness when modelling light-absorbing aerosol climate forcing.
Roland Stirnberg, Jan Cermak, Simone Kotthaus, Martial Haeffelin, Hendrik Andersen, Julia Fuchs, Miae Kim, Jean-Eudes Petit, and Olivier Favez
Atmos. Chem. Phys., 21, 3919–3948,Short summary
Air pollution endangers human health and poses a problem particularly in densely populated areas. Here, an explainable machine learning approach is used to analyse periods of high particle concentrations for a suburban site southwest of Paris to better understand its atmospheric drivers. Air pollution is particularly excaberated by low temperatures and low mixed layer heights, but processes vary substantially between and within seasons.
Julia Schneider, Kristina Höhler, Paavo Heikkilä, Jorma Keskinen, Barbara Bertozzi, Pia Bogert, Tobias Schorr, Nsikanabasi Silas Umo, Franziska Vogel, Zoé Brasseur, Yusheng Wu, Simo Hakala, Jonathan Duplissy, Dmitri Moisseev, Markku Kulmala, Michael P. Adams, Benjamin J. Murray, Kimmo Korhonen, Liqing Hao, Erik S. Thomson, Dimitri Castarède, Thomas Leisner, Tuukka Petäjä, and Ottmar Möhler
Atmos. Chem. Phys., 21, 3899–3918,Short summary
By triggering the formation of ice crystals, ice-nucleating particles (INP) strongly influence cloud formation. Continuous, long-term measurements are needed to characterize the atmospheric INP variability. Here, a first long-term time series of INP spectra measured in the boreal forest for more than 1 year is presented, showing a clear seasonal cycle. It is shown that the seasonal dependency of INP concentrations and prevalent INP types is driven by the abundance of biogenic aerosol.
Kevin J. Sanchez, Gregory C. Roberts, Georges Saliba, Lynn M. Russell, Cynthia Twohy, J. Michael Reeves, Ruhi S. Humphries, Melita D. Keywood, Jason P. Ward, and Ian M. McRobert
Atmos. Chem. Phys., 21, 3427–3446,Short summary
Measurements of particles and their properties were made from aircraft over the Southern Ocean. Aerosol transported from the Antarctic coast is shown to greatly enhance particle concentrations over the Southern Ocean. The occurrence of precipitation was shown to be associated with the lowest particle concentrations over the Southern Ocean. These particles are important due to their ability to enhance cloud droplet concentrations, resulting in more sunlight being reflected by the clouds.
Arnott, W. P., Hamasha, K., Moosmüller, H., Sheridan, P. J., and Ogren, J. A.: Towards aerosol light-absorption measurements with 7-wavelength Aethalometer: evaluation with a photoacoustic instrument and 3-wavelength Nephelometer, Aerosol Sci. Tech., 39, 17–29, 2005.
Babu, S. S., Sreekanth, V., Moorthy, K. K., Mohan, M., Kirankumar, N., Subrahamanyam, D. B., Gogoi, M. M., Kompalli, S. K., Beegum, N., Chaubey, J. P., Kumar, V. A., and Manchanda, R. K.: Vertical profiles of aerosol black carbon in the atmospheric boundary layer over a tropical coastal station: perturbations during an annular solar eclipse, Atmos. Res., 99, 471–478, 2011.
Bond, T. C. and Bergstrom, R. W.: Light absorption by carbon particle: an investigative review, Aerosol Sci. Tech., 40, 27–67, 2006.
Bond, T. C., Doherty, S. J., Fahey, D. W., Forster, P. M., Berntsen, T., DeAngelo, B. J., Flanner, M. G., Ghan, S., Kärcher, B., Koch, D., Kinne, S., Kondo, Y., Quinn, P. K., Sarofim, M. C., Schultz, M. G., Schulz, M., Venkataraman, C., Zhang, H., Zhang, S., Bellouin, N., Guttikunda, S. K., Hopke, P. K., Jacobson, M. Z., Kaiser, J. W., Klimont, Z., Lohmann, U., Schwarz, J. P., Shindell, D., Storelvmo, T., Warren, S. G., and Zender, C. S.: Bounding the role of black carbon in the climate system: a scientific assessment, J. Geophys. Res.-Atmos., 118, 5380–5552, 2013.
Bosch, C., Andersson, A., Kirillova, E., Budhavant, K., Tiwari, S., Praveen, P. S., Russel, L. M., Beres, N. D., Ramanathan, V., and Gustafsson, Ö.: Source-diagnostic dual-isotope composition and optical properties water-soluble organic carbon and elemental carbon in South Asian outflow intercepted over the Indian Ocean, J. Geophys. Res., 119, 11743–11759, 2014.
Boucher, O., Randall, D., Artaxo, P., Bretherton, C., Feingold, G., Forster, P., Kerminen, V.-M., Kondo, Y., Liao, H., Lohmann, U., Rasch, P., Satheesh, S. K., Sherwood, S., Stevens, B., and Zhang, X. Y.: Clouds and aerosols, in: Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change, Cambridge University Press, Cambridge, UK and New York, NY, USA, 614–623, 2013.
Chakrabarty, R. K., Nicholas, D. B., Moosmüller, H., China, S., Mazzoleni, C., Dubey, M. K., Liu, L., and Mishchenko, I.: Soot superaggregates from flaming wildfires and their direct radiative forcing, Nature, scientific report, 4, 5508, https://doi.org/10.1038/srep05508, 2014.
Clarke, A. D., Howell, S. G., Quinn, P. K., Bates, T. S., Ogren, J., Andrews, E. A. J., Massling, A., Mayol-Bracero, O., Maring, H., Savoie, D., and Cass, G. R.: INDOEX aerosl: a comparison and summary of chemical, microphysical, and optical properties observed from land, ship, and aircraft, J. Geophys. Res., 107, D198033, https://doi.org/10.1029/2001JD000572, 2002.
Collins, D. R., Johnsson, H. H., Seinfeld, J. H., Flagan, R. C., Gasso, S., Hegg, D. A., Russell, P. B., Schmid, B., Livingston, J. M., Öström, E., Noone, K. J., Russel, L. M., and Putaud, J. P.: In situ aerosol-size distributions and clear-column radiative closure during ACE-2, Tellus B, 52, 498–525, 2000.
Corrigan, C. E., Ramanathan, V., and Schauer, J. J.: Impact of monsoon transitions on the physical and optical properties of aerosols, J. Geophys. Res., 111, D18208, https://doi.org/10.1029/2005JD006370, 2006.
Dey, S. and Di Girolamo, L.: A climatology of aerosol optical and microphysical properties over the Indian subcontinent from 9 years (2000–2008) of Multiangle Imaging Spectroradiometer (MISR) data, J. Geophys. Res., 115, D15204, https://doi.org/10.1029/2009JD013395, 2010.
Engström, J. E. and Leck, C.: Reducing uncertainties associated with filter-based optical measurements of light absorbing carbon particles with chemical information, Atmos. Meas. Tech., 4, 1553–1566, https://doi.org/10.5194/amt-4-1553-2011, 2011.
Fernald, F. G.: Analysis of atmospheric lidar observations: Some comments, Appl. Opt., 23, 652–653, 1984.
Franke, K., Ansmann, A., Müller, D., Althausen, D., Venkataraman, C., Reddy, M. S., Wagner, F., and Scheele, R.: Optical properties of the Indo–Asian haze layer over the tropical Indian Ocean, J. Geophys. Res., 108, D24059, https://doi.org/10.1029/2002JD002473, 2003.
Granier, C., Bessagnet, B., Bond, T., D'Angiola, A., Denier van der Gon, H., Frost, G. J., Heil, A., Kaiser, J. W., Kinne, S., Klimont, Z., Kloster, S., Lamarque, J.-F., Liousse, C., Masui, T., Meleux, F., Mieville, A., Ohara, T., Raut, J.-C., Riahi, K., Schultz, M. G., Smith, S. J., Thompson, A., van Aardenne, J., van der Werf, G. R., and van Vuuren, D. P.: Evolution of anthropogenic and biomass burning emissions of air pollutants at global and regional scales during the 1980–2010 period, Climatic Change, 109, 163–190, 2011.
Gustafsson, Ö., Kruså, M., Zencak, Z., Sheesley, R. J., Granat, L., Engström, E., Praveen, P. S., Rao, P. S. P., Leck, C., and Rodhe, H.: Brown cloud over south Asia: biomass or fossil fuel combustion, Science, 323, 495–498, 2009.
Heintzenberg, J., Covert, D. C., and Van Dingenen, R.: Size distribution and chemical composition of marine aerosols: a compilation and review, Tellus B, 52, 1104–1122, 2000.
Holben, B. N., Eck, T. F., Slutsker, I., Tanre, D., P., B. J., Setzer, A., Vermote, E., Reagan, J. A., Kaufman, Y. J., Nakajima, T., Lavenu, F., Jankowiak, I., and Smirnov, A.: Aeronet – a federated instrument network and data archive for aerosol characterization, Remote Sens. Environ., 66, 1–16, 1998.
Holland, G. H., Webster, P. J., Curry, J. A., Tyrell, G., Gauntlett, D., Brett, G., Becker, J., Hoag, R., and Vaglienti, W.: The aerosonde robotic aircrafts: a new paradigm for environmental observations, B. Am. Meteorol. Soc., 82, 889–901, 2001.
Klett, J. D.: Stable analytical inversion solution for processing lidar returns, Appl. Opt., 20, 211–220, 1981
Lawrence, M. G. and Lelieveld, J.: Atmospheric pollutant outflow from southern Asia: a review, Atmos. Chem. Phys., 10, 11017–11096, https://doi.org/10.5194/acp-10-11017-2010, 2010.
Lelieveld, J., Crutzen, P. J., Ramanathan, V., Andreae, M. O., Brenninkmeijer, C. A. M., Campos, T., Cass, G. R., Dickerson, R., Fischer, H., de Gouw, J. A., Hansel, A., Jefferson, M. G., Kley, D., de Laat, A. T. J., Lal, S., Lawrence, M. G., Lobert, J. M., mayol Bracero, O. L., Mitra, A. P., Novakov, T., Oltmans, S. J., Prather, K. A., Reiner, T., Rodhe, H., Scheeren, H. A., Sikka, D., and Williams, J.: The Indian Ocean Experiment: widespread air pollution from south and southeast Asia, Science, 291, 1031–1036, 2001.
Maßling, A., Wiedensohler, A., Busch, B., Neusüß, C., Quinn, P., Bates, T., and Covert, D.: Hygroscopic properties of different aerosol types over the Atlantic and Indian Oceans, Atmos. Chem. Phys., 3, 1377–1397, https://doi.org/10.5194/acp-3-1377-2003, 2003.
Moorthy, K. K., Sunilkumar, S. V., Pillai, P. S., Parameswaran, K., Nair, P. R., Ahmed, Y. N., Ramgopal, K., Narasimhulu, K., Reddy, R. R., Vinoj, V., Satheesh, S. K., Niranjan, K., Rao, B. M., Brahmanandam, P. S., Saha, A., Badarinath, K. V. S., Kiranchand, T. R., and Latha, K. M.: Wintertime spatial characteristics of boundary layer aerosols over peninsular India, J. Geophys. Res.-Atmos., 110, D08207, https://doi.org/10.1029/2004JD005520, 2005.
Moorthy, K. K., Satheesh, S. K., Babu, S. S., and Dutt, C. B. S.: Integrated Campaign for Aerosols, Gases and Radiation Budget (ICARB): an overview, J. Earth Syst. Sci., 117, 243–262, 2008.
Müller, D., Franke, K., Ansmann, A., and Althausen, D.: Indo-Asian pollution during INDOEX: Microphysical particle properties and single-scattering albedo inferred from multiwavelength lidar observations, J. Geophys. Res., 108, 4600, https://doi.org/10.1029/2003JD003538, 2003.
Müller, D., Ansmann, A., Mattis, I., Tesche, M., Wandinger, U., Althausen, D., and Pisani, G.: Aerosol-type-dependent lidar ratios observed with Raman lidar, J. Geophys. Res. Atmos., 112, D16202, https://doi.org/10.1029/2006JD00829, 2007.
Liu, Y. and Daum, P. H.: The effect of refractive index on size distributions and light scattering coefficients derived from optical particle counters, J. Aerosol. Sci., 31, 945–957, 2000.
Oshima, N., Kondo, Y., Moteki, N., Takegawa, N., Koike, M., Kita, K., Matsui, H., Kajino, M., Nakamura, H., Jung, J. S., and Kim, Y. J.: Wet removal of black carbon in Asian outflow: Aerosol Radiative Forcing in East Asia (A-FORCE) aircraft campaign, J. Geophys. Res.-Atmos., 117, D03204, https://doi.org/10.1029/2011JD016552, 2012.
Petzold, A., Ogren, J. A., Fiebig, M., Laj, P., Li, S.-M., Baltensperger, U., Holzer-Popp, T., Kinne, S., Pappalardo, G., Sugimoto, N., Wehrli, C., Wiedensohler, A., and Zhang, X.-Y.: Recommendations for reporting “black carbon” measurements, Atmos. Chem. Phys., 13, 8365–8379, https://doi.org/10.5194/acp-13-8365-2013, 2013.
Pistone, K., Praveen, P. S., Thomas, R. M., Ramanathan, V., Wilcox, E., and Bender, F. A.-M.: Observed correlations between aerosol and cloud properties in an Indian Ocean trade cumulus regime, Atmos. Chem. Phys. Discuss., 15, 29347–29402, https://doi.org/10.5194/acpd-15-29347-2015, 2015.
Ramana, M. V. and Ramanathan, V.: Abrupt transition from natural to anthropogenic aerosol radiative forcing: observations at the ABC-Maldives Climate Observatory, J. Geophys. Res., 111, D20207, https://doi.org/10.1029/2006JD007063, 2006.
Ramanathan, V., Crutzen, P. J., Lelieveld, J., Mitra, A. P., Althausen, D., Anderson, J., Andreae, M. O., Cantrell, W., Cass, G. R., Chung, C. E., Clarke, A. D., Coakley, J. A., Collins, W. D., Conant, W. C., Dulac, F., Heintzenberg, J., Heymsfield, A. J., Holben, B. N., Howell, S. G., Hudson, J., Jayaraman, A., Kiehl, J. T., Krishnamurti, T. N., Lubin, D., McFarquhar, G., Novakov, T., Ogren, J. A., Podgorny, I. A., Prather, K. A., Priestley, K., Prospero, J. M., Quinn, P. K., Rajeev, K., Rasch, P., Rupert, S., Sadourny, R., Satheesh, S. K., Shaw, G. E., Sheridan, P., and Valero, F. P. J.: Indian Ocean Experiment: an integrated analysis of the climate forcing and effects of the great Indo–Asian haze, J. Geophys. Res., 106, 28371–28398, 2001.
Ramanathan, V., Li, M. V., Ramana, M. V., Praveen, P. S., Kim, D., Corrigan, C. E., and Nguyen, H.: Atmospheric Brown Clouds: Hemispherical and regional variations in long range transport, absorption, and radiative forcing, J. Geophys. Res., 112, D22S21, https://doi.org/10.1029/2006JD008124, 2007.
Ramanathan, V., Thomas, R. M., Praveen, P. S., Nguyen, H. V., Wilcox, E., Bender, F. A.-M., Pistone, K.: Cloud Aerosol Radiative Forcing Dynamics EXperiment (CARDEX), available at: http://www-ramanathan.ucsd.edu/files/CARDEX_prop_Jun_20.pdf (last access: 16 December 2015), 2011.
Samset, B. H., Myhre, G., Herber, A., Kondo, Y., Li, S.-M., Moteki, N., Koike, M., Oshima, N., Schwarz, J. P., Balkanski, Y., Bauer, S. E., Bellouin, N., Berntsen, T. K., Bian, H., Chin, M., Diehl, T., Easter, R. C., Ghan, S. J., Iversen, T., Kirkevåg, A., Lamarque, J.-F., Lin, G., Liu, X., Penner, J. E., Schulz, M., Seland, Ø., Skeie, R. B., Stier, P., Takemura, T., Tsigaridis, K., and Zhang, K.: Modelled black carbon radiative forcing and atmospheric lifetime in AeroCom Phase II constrained by aircraft observations, Atmos. Chem. Phys., 14, 12465–12477, https://doi.org/10.5194/acp-14-12465-2014, 2014.
Sheridan, P. J., Jefferson, A., and Ogren, J. A.: Spatial variability of submicrometer aerosol radiative properties over the Indian Ocean during INDOEX, J. Geophys. Res., 107, INX2 10-1–INX2 10-17, https://doi.org/10.1029/2000JD000166, 2002.
Sheridan, P. J., Andrews, E., Ogren, J. A., Tackett, J. L., and Winker, D. M.: Vertical profiles of aerosol optical properties over central Illinois and comparison with surface and satellite measurements, Atmos. Chem. Phys., 12, 11695–11721, https://doi.org/10.5194/acp-12-11695-2012, 2012.
Thomas, R. M., Lehmann, K., Nguyen, H., Jackson, D. L., Wolfe, D., and Ramanathan, V.: Measurement of turbulent water vapor fluxes using a lightweight unmanned aerial vehicle system, Atmos. Meas. Tech., 5, 243–257, https://doi.org/10.5194/amt-5-243-2012, 2012.
Titos, G., Jefferson, A., Sheridan, P. J., Andrews, E., Lyamani, H., Alados-Arboledas, L., and Ogren, J. A.: Aerosol light-scattering enhancement due to water uptake during the TCAP campaign, Atmos. Chem. Phys., 14, 7031–7043, https://doi.org/10.5194/acp-14-7031-2014, 2014.
Welton, E. J., Voss, K. J., Gordon, H. R., Maring, H., Smirnov, A., Holben, B., Schmid, B., and Livingston, J. M., Russell, P. B., Durkee, P. A., Formenti, P., and Andreae, M. O.: Ground-based lidar measurements of aerosols during ACE-2: instrument description, results, and comparisons with other ground-based and airborne measurements, Tellus B, 52, 636–651, 2000.
Welton, E. J., Voss, K. J., Quinn, P. K., Flatau, P. J., Markowicz, K., Campbell, J. R., Spinhirne, J. D., Gordon, H. R., and Johnson, J. E.: Measurements of aerosol vertical profiles and optical properties during INDOEX 1999 using micropulse lidars, J. Geophys. Res.-Atmos., 107, INX2-1–INX2-20, https://doi.org/10.1029/2000JD000038, 2002.
Wofsy, S.: HIAPER Pole-to-Pole Observations (HIPPO): fine-grained, global-scale measurements of climatically important atmospheric gases and aerosols, Philos. T. R. Soc. A, 369, 2073–2086, 2011.
Yang, M., Howell, S. G., Zhuang, J., and Huebert, B. J.: Attribution of aerosol light absorption to black carbon, brown carbon, and dust in China – interpretations of atmospheric measurements during EAST-AIRE, Atmos. Chem. Phys., 9, 2035–2050, https://doi.org/10.5194/acp-9-2035-2009, 2009.
Zieger, P., Fierz-Schmidhauser, R., Weingartner, E., and Baltensperger, U.: Effects of relative humidity on aerosol light scattering: results from different European sites, Atmos. Chem. Phys., 13, 10609–10631, https://doi.org/10.5194/acp-13-10609-2013, 2013.
The paper presents aerosol properties measured during the Cloud Aerosol Radiative Forcing Experiment (CARDEX) on the Maldives Islands in winter 2012. The vertical distribution of absorbing aerosol which is very relevant to the radiative forcing in that region, is investigated. A method for determining particle absorption and equivalent black carbon concentration from lidar extinction coefficients, characteristic single scattering albedo and mass absorption efficiency, is presented and evaluated.
The paper presents aerosol properties measured during the Cloud Aerosol Radiative Forcing...