Long-term cloud condensation nuclei number concentration, particle number size distribution and chemical composition measurements at regionally representative observatories
View/ Open
Full Text
Date
2018-02-28Author
Schmale, Julia
Henning, Silvia
Decesari, Stefano
Henzing, Bas
Keskinen, Helmi
Sellegri, Karine
Ovadnevaite, Jurgita
Pöhlker, Mira L.
Brito, Joel
Bougiatioti, Aikaterini
Kristensson, Adam
Kalivitis, Nikos
Stavroulas, Iasonas
Carbone, Samara
Jefferson, Anne
Park, Minsu
Schlag, Patrick
Iwamoto, Yoko
Aalto, Pasi
Äijälä, Mikko
Bukowiecki, Nicolas
Ehn, Mikael
Frank, Göran
Fröhlich, Roman
Frumau, Arnoud
Herrmann, Erik
Herrmann, Hartmut
Holzinger, Rupert
Kos, Gerard
Kulmala, Markku
Mihalopoulos, Nikolaos
Nenes, Athanasios
O'Dowd, Colin
Petäjä, Tuukka
Picard, David
Pöhlker, Christopher
Pöschl, Ulrich
Poulain, Laurent
Prévôt, André Stephan Henry
Swietlicki, Erik
Andreae, Meinrat O.
Artaxo, Paulo
Wiedensohler, Alfred
Ogren, John
Matsuki, Atsushi
Yum, Seong Soo
Stratmann, Frank
Baltensperger, Urs
Gysel, Martin
Metadata
Show full item recordUsage
This item's downloads: 0 (view details)
Cited 42 times in Scopus (view citations)
Recommended Citation
Schmale, Julia; Henning, Silvia; Decesari, Stefano; Henzing, Bas; Keskinen, Helmi; Sellegri, Karine; Ovadnevaite, Jurgita; Pöhlker, Mira L. Brito, Joel; Bougiatioti, Aikaterini; Kristensson, Adam; Kalivitis, Nikos; Stavroulas, Iasonas; Carbone, Samara; Jefferson, Anne; Park, Minsu; Schlag, Patrick; Iwamoto, Yoko; Aalto, Pasi; Äijälä, Mikko; Bukowiecki, Nicolas; Ehn, Mikael; Frank, Göran; Fröhlich, Roman; Frumau, Arnoud; Herrmann, Erik; Herrmann, Hartmut; Holzinger, Rupert; Kos, Gerard; Kulmala, Markku; Mihalopoulos, Nikolaos; Nenes, Athanasios; O'Dowd, Colin; Petäjä, Tuukka; Picard, David; Pöhlker, Christopher; Pöschl, Ulrich; Poulain, Laurent; Prévôt, André Stephan Henry; Swietlicki, Erik; Andreae, Meinrat O.; Artaxo, Paulo; Wiedensohler, Alfred; Ogren, John; Matsuki, Atsushi; Yum, Seong Soo; Stratmann, Frank; Baltensperger, Urs; Gysel, Martin (2018). Long-term cloud condensation nuclei number concentration, particle number size distribution and chemical composition measurements at regionally representative observatories. Atmospheric Chemistry and Physics 18 (4), 2853-2881
Published Version
Abstract
Aerosol-cloud interactions (ACI) constitute the single largest uncertainty in anthropogenic radiative forcing. To reduce the uncertainties and gain more confidence in the simulation of ACI, models need to be evaluated against observations, in particular against measurements of cloud condensation nuclei (CCN). Here we present a data set - ready to be used for model validation - of long-term observations of CCN number concentrations, particle number size distributions and chemical composition from 12 sites on 3 continents. Studied environments include coastal background, rural background, alpine sites, remote forests and an urban surrounding. Expectedly, CCN characteristics are highly variable across site categories. However, they also vary within them, most strongly in the coastal background group, where CCN number concentrations can vary by up to a factor of 30 within one season. In terms of particle activation behaviour, most continental stations exhibit very similar activation ratios (relative to particles > 20 nm) across the range of 0.1 to 1.0% supersaturation. At the coastal sites the transition from particles being CCN inactive to becoming CCN active occurs over a wider range of the supersaturation spectrum.
Several stations show strong seasonal cycles of CCN number concentrations and particle number size distributions, e. g. at Barrow (Arctic haze in spring), at the alpine stations (stronger influence of polluted boundary layer air masses in summer), the rain forest (wet and dry season) or Finokalia (wildfire influence in autumn). The rural background and urban sites exhibit relatively little variability throughout the year, while short-term variability can be high especially at the urban site.
The average hygroscopicity parameter, kappa, calculated from the chemical composition of submicron particles was highest at the coastal site of Mace Head (0.6) and lowest at the rain forest station ATTO (0.2-0.3). We performed closure studies based on kappa-Kohler theory to predict CCN number concentrations. The ratio of predicted to measured CCN concentrations is between 0.87 and 1.4 for five different types of kappa. The temporal variability is also well captured, with Pearson correlation coefficients exceeding 0.87.
Information on CCN number concentrations at many locations is important to better characterise ACI and their radiative forcing. But long-term comprehensive aerosol particle characterisations are labour intensive and costly. Hence, we recommend operating "migrating-CCNCs" to conduct collocated CCN number concentration and particle number size distribution measurements at individual locations throughout one year at least to derive a seasonally resolved hygroscopicity parameter. This way, CCN number concentrations can only be calculated based on continued particle number size distribution information and greater spatial coverage of longterm measurements can be achieved.