Composition, isotopic fingerprint and source attribution of nitrate deposition from rain and fog at a Sub-Arctic Mountain site in Central Sweden (Mt Åreskutan)

Carmen P. Vega, E. Monica Mårtensson, Ulla Wideqvist, Jan Kaiser, Paul Zieger, Johan Ström
2019 | Tellus Ser. B-Chem. Phys. Meteorol.

Interactions between the atmosphere, cryosphere and ecosystems at northern high latitudes

Michael Boy; Erik S. Thomson; Juan-C. Acosta Navarro; Olafur Amalds; Ekaterina Batchvarova; Jaana K. Bäck; Frank Berninger; Merete Bilde; Pavla Dagsson Waldhuserova; Dimistri Castaréde; Maryam Dalirian; Gerrit de Leeuw; Monika Wittman; Ella-Maria Duplissy (nèe Kyrö); J. Duplissy; A. M. L. Ekman; Keyan Fang; Jean-Charlet Gallet; Marianne Glasius; Sven-Erik Gryning; Henrik Grythe; Hans-Christen Hansson; Margareta Hansson; Elisabeth Isaksson; Trond Iverson; Ingibjörg Jónsdottir; Ville Kasurinen; Alf Kirkevåg; Atte Korhola; Radovan Krejci; Jon Egill Kristjansson; Hanna K. Lappalainen; Antti Lauri; Matti Leppäranta; Heikki Livhvainen: Risto Makkonon; Andreas Massling; Outi Meinander; E Douglas Nilsson; Haraldur Ólofsson; Jan B. C. Pettersson; Nonne L. Prisle; Ilona Riipinen; Pontus Roldin; Meri Ruppel; Matt Edward Salter; Maria Sand; Ovind Seland; Heikki Seppä; Henrik Skov; Joanna Soares; Andreas Stohl; Johan Ström; Jonas Svensson; Erik Swietlicki; Ksenia Tabakova; Thorstur Torsteinsson; Aki Virkula; Gesa A. Weyhenmeyer; Yusheng Wu; Paul Zieger; Markku Kulmala
2019 | Atmos. Chem. Phys. | 19 (2015-2061)

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, aiming to strengthen research and innovation regarding climate change issues in the Nordic region. CRAICC gathered more than 100 scientists from all Nordic countries in a virtual centre with the objectives of identifying and quantifying the major processes controlling Arctic warming and related feedback mechanisms, outlining strategies to mitigate Arctic warming, and developing Nordic Earth system modelling with a focus on short-lived climate forcers (SLCFs), including natural and anthropogenic aerosols.

The outcome of CRAICC is reflected in more than 150 peer-reviewed scientific publications, most of which are in the CRAICC special issue of the journal Atmospheric Chemistry and Physics. This paper presents an overview of the main scientific topics investigated in the centre and provides the reader with a state-of-the-art comprehensive summary of what has been achieved in CRAICC with links to the particular publications for further detail. Faced with a vast amount of scientific discovery, we do not claim to completely summarize the results from CRAICC within this paper, but rather concentrate here on the main results which are related to feedback loops in climate change–cryosphere interactions that affect Arctic amplification.

Cloud droplet activation of black carbon particles with organic compounds of varying solubility

Dalirian, M.; Ylisirnio, A.; Buchholz, A.; Schlesinger, D.; Strom, J.; Virtanen, A.; Riipinen, I.
2018 | Atmos. Chem. Phys. | 18 (12477-12489)

Light-absorption of dust and elemental carbon in snow in the Indian Himalayas and the Finnish Arctic

Svensson, J.; Strom, J.; Kivekas, N.; Dkhar, NB.; Tyal, S.; Sharman, VP.; Jutila, A.; Backman, J.; Virkkula, A.; Ruppel, M.; Hyverinen, A.; Kontu, A.; Hannula, HR.; Lepparanta, M.; Hooda, RK.; Korhola, A.; Asmi, E.; Lihavainen, H.
2018 | Atmos. Meas. Tech. | 11 (1403-1416)

The seasonal characteristics of cloud condensation nuclei (CCN) in the arctic lower troposphere

Jung, CH; Yoon, YJ; Kang, HJ; Gim, Y; Lee, BY; Strom, J; Krejci, R; Tunved, P
2018 | Tellus Ser. B-Chem. Phys. Meteorol. | 70 (1-13)
aerosol-particles , arctic aerosol , arctic troposphere , atmosphere , ccn , climate , cycle , ny-alesund , ocean , size distributions , summer aerosol , svalbard , zeppelin station
Cloud Condensation Nuclei (CCN) concentration and aerosol size distributions in the Arctic were collected during the period 2007-2013 at the Zeppelin observatory (78.91 degrees N, 11.89 degrees E, 474 masl). Annual median CCN concentration at a supersaturation (SS) of 0.4% show the ranges of 45 approximate to 81cm(-3). The monthly median CCN number density varied between 17cm(-3) in October 2007 and 198cm(-3) in March, 2008. The CCN spectra parameters C (83cm(-3)) and k (0.23) were derived. In addition, calculated annual median value of hygroscopicity parameter is 0.46 at SS of 0.4%. Particle number concentration of accumulation mode from aerosol size distribution measurements are well correlated with CCN concentration. The CCN to CN>10 nm (particle number concentration larger than 10nm in diameter) ratio shows a maximum during March and minimum during July. The springtime high CCN concentration is attributed to high load of accumulation mode aerosol transported from the mid-latitudes, known as Arctic Haze. CCN concentration remains high also during Arctic summer due to the source of new CCN through particle formation followed by consecutive aerosol growth. Lowest aerosol as well as CCN number densities were observed during Arctic autumn and early winter when aerosol formation in the Arctic and long-range transport into the Arctic are not effective.

Arctic sea ice melt leads to atmospheric new particle formation.

Dall'Osto, M.; Beddows, DCS.; Tunved, P.; Krejci, R.; Strom, J.; Hansson, HC.; Yoon, YJ.; Park, KT.; Becagli, S.; Udisti, R.; Onasch, T.; O'Dowd, CD.; Simo, R.; Harrison, RM.
2017 | Sci Rep | 10

A new aerosol wet removal scheme for the Lagrangian particle model FLEXPART v10

Grythe, H.; Kristiansen, N.; Zwaaftink, CDG.; Eckhardt, S.; Strom, J.; Tunved, P.; Krejci, R.; Stohl, A.
2017 | Geosci. Model Dev. | 10 (1447-1466)

Do contemporary (1980-2015) emissions determine the elemental carbon deposition trend at Holtedahlfonna glacier, Svalbard?

Ruppel, MM.; Soares, J.; Gallet, JC.; Isaksson, E.; Martma, T.; Svensson, J.; Kohler, J.; Pedersen, CA.; Manninen, S.; Korhola, A.; Strom, J.
2017 | Atmos. Chem. Phys. | 17 (12779-12795)

Trends in black carbon and size-resolved particle number concentrations and vehicle emission factors under real-world conditions

Krecl, P.; Johansson, C.; Targino, A.C.; Ström, J.; Burman, L.
2017 | Atmos Environ | 165 (155-168)

Kerbside concentrations of NOx, black carbon (BC), total number of particles (diameter > 4 nm) and number size distribution (28–410 nm) were measured at a busy street canyon in Stockholm in 2006 and 2013. Over this period, there was an important change in the vehicle fleet due to a strong dieselisation process of light-duty vehicles and technological improvement of vehicle engines. This study assesses the impact of these changes on ambient concentrations and particle emission factors (EF). EF were calculated by using a novel approach which combines the NOx tracer method with positive matrix factorisation (PMF) applied to particle number size distributions. NOx concentrations remained rather constant between these two years, whereas a large decrease in particle concentrations was observed, being on average 60% for BC, 50% for total particle number, and 53% for particles in the range 28–100 nm. The PMF analysis yielded three factors that were identified as contributions from gasoline vehicles, diesel fleet, and urban background. This separation allowed the calculation of the average vehicle EF for each particle metric per fuel type. In general, gasoline EF were lower than diesel EF, and EF for 2013 were lower than the ones derived for 2006. The EFBC decreased 77% for both gasoline and diesel fleets, whereas the particle number EF reduction was higher for the gasoline (79%) than for the diesel (37%) fleet. Our EF are consistent with results from other on-road studies, which reinforces that the proposed methodology is suitable for EF determination and to assess the effectiveness of policies implemented to reduce vehicle exhaust emissions. However, our EF are much higher than EF simulated with traffic emission models (HBEFA and COPERT) that are based on dynamometer measurements, except for EFBC for diesel vehicles. This finding suggests that the EF from the two leading models in Europe should be revised for BC (gasoline vehicles) and particle number (all vehicles), since they are used to compile national inventories for the road transportation sector and also to assess their associated health effects. Using the calculated kerbside EF, we estimated that the traffic emissions were lower in 2013 compared to 2006 with a 61% reduction for BC (due to decreases in both gasoline and diesel emissions), and 34–45% for particle number (reduction only in gasoline emissions). Limitations of the application of these EF to other studies are also discussed.

Chemical composition and source analysis of carbonaceous aerosol particles at a mountaintop site in central Sweden

Vera Franke; Paul Zieger; Ulla Wideqvist; Juan Camilo Acosta Navarro; Caroline Leck; Peter Tunved; Bernadette Rosati; Martin Gysel; Matthew Salter; Johan Ström
2017 | Tellus Ser. B-Chem. Phys. Meteorol. | 69 (1)

Multi-seasonal ultrafine aerosol particle number concentration measurements at the Gruvebadet observatory, Ny-lesund, Svalbard Islands

Lupi, A; Busetto, M; Becagli, S; Giardi, F; Lanconelli, C; Mazzola, M; Udisti, R; Hansson, HC; Henning, T; Petkov, B; Strom, J; Krejci, R; Tunved, P; Viola, AP; Vitale, V
2016 | Rend. Lincei.-Sci. Fis. Nat. | 27 (59-71)
aerosol size distribution , alesund , arctic aerosol , arctic air-pollution , arctic haze , boundary layer , cycle , lognormal fitting procedure , size distributions , summer , ultrafine aerosol concentration , winter , zeppelin station
The object of this study was to investigate the different modal behavior of ultrafine aerosol particles collected at the Gruvebadet observatory located in Ny-lesund (Svalbard Islands, 78A degrees 55'N, 11A degrees 56'E). Aerosol particle size distribution was measured in the size range from 10 to 470 nm typically from the beginning of spring to the beginning of fall during four (non-consecutive) years (2010, 2011, 2013 and 2014). The median concentration for the whole period taken into account was 214 particles cm(-3), oscillating between the median maximum in July with a concentration of 257 particles cm(-3) and a median minimum in April with 197 particles cm(-3). The median total number concentration did not present a well-defined seasonal behavior, as shown by contrast looking at the sub/modal number concentration, where distinct trends appeared in the predominant accumulation concentration recorded during April/May and the preponderant concentration of Aitken particles during the summer months. Lastly, the short side-by-side spring 2013 campaign performed at the Zeppelin observatory with a differential mobility particle sizer was characterized by an aerosol concentration mean steady difference between the two instruments of around 14 %, thereby supporting the reliability of the device located at Gruvebadet.

In-situ observations of black carbon in snow and the corresponding spectral surface albedo reduction

Pedersen, C. A.; J.-C. Gallet; J. Ström; S. Gerland; S. R. Hudson; S. Forsström; E. Isaksson; T. K. Berntsen
2015 | J. Geophys. Res.-Atmos. | 120 (13803-13817)

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