Synthesis of the ACTRIS Network Cloud Condensation Nuclei Measurements

Wednesday, 16 December 2015
Poster Hall (Moscone South)
Julia Schmale1, J. S. Henzing2, G. P. a. Kos3, Patrick Schlag4, Rupert Holzinger5, Pasi Aalto6, Helmi Keskinen6, Mikhail Paramonov6, Frank Stratmann7, Silvia Henning7, Laurent Poulain7, Karine Sellegri8, Jurgita Ovadnevaite9, Mira L. Krüger10, Samara Carbone11, Joel Brito12, Anne Jefferson13, James Whitehead14, Ken S Carslaw15, Roman Fröhlich1, Erik Herrmann1, Emanuel Hammer1, Martin Gysel16, Ghislain Motos16, Nicolas Bukowiecki16, Astrid Kiendler-Scharr17, Mikko Äijälä6, Liine Heikkinen6, Tuukka Petäjä6, Markku Tapio Kulmala6, Alfred Wiedensohler18, Andre Sonntag7, Wolfram Birmili7, David Picard8, Colin D. D. O'Dowd19, Jakub Bialek19, Christopher Pöhlker10, Hang Su10, Ulrich Poeschl10, Meinrat O Andreae10, Paulo Artaxo20, Henrique M Barbosa21, John A Ogren22, Gordon McFiggans23, Erik Swietlicki24, Göran Frank24, Urs Baltensperger1, Wencke Aas25 and Markus Fiebig25, (1)Paul Scherrer Institute, Villingen, Switzerland, (2)Netherlands Organization for Applied Scientific Research, Utrecht, Netherlands, (3)Energy Research Centre of the Netherlands, Petten, Netherlands, (4)Forschungszentrum Jülich, Jülich, Germany, (5)Utrecht University, Utrecht, Netherlands, (6)University of Helsinki, Helsinki, Finland, (7)Leibniz Institute for Tropospheric Research, Leipzig, Germany, (8)Laboratoire de Météorologie Physique Observatoire de Physique du Globe de Clermont-Ferrand, Aubiere Cedex, France, (9)National University of Ireland, Galway, Ireland, (10)Max Planck Institute for Chemistry, Mainz, Germany, (11)USP University of Sao Paulo, Institute of Physics, São Paulo, Brazil, (12)Universidade de São Paulo, Instituto de Física, São Paulo, Brazil, (13)University of Colorado at Boulder, Boulder, CO, United States, (14)University of Manchester, Manchester, United Kingdom, (15)University of Leeds, Leeds, United Kingdom, (16)Paul Scherrer Institute, Villigen PSI, Switzerland, (17)Forschungszentrum Jülich GmbH, Jülich 52428, Germany, (18)Leibniz-Institute for Tropospheric Research, Leipzig, Germany, (19)University of Ireland in Galway, Galway, Ireland, (20)USP University of Sao Paulo, São Paulo, Brazil, (21)University of Sao Paulo, Sao Paulo, United States, (22)NOAA Boulder, ESRL/GMD, Boulder, CO, United States, (23)University of Manchester, School of Earth, Atmospheric and Environmental Sciences, Manchester, United Kingdom, (24)Lund University, Lund, Sweden, (25)Norwegian Institute for Air Research, Kjeller, Norway
We present results of cloud condensation nuclei (CCN) measurements between 2011 and 2014 from several ACTRIS stations (http://www.actris.net/), two urban datasets, and Barrow, Alaska (2007/08). Aerosol number concentration, size distribution and chemical composition are also analyzed to derive further key variables such as the hygroscopicity parameter kappa and the activation diameters at several supersaturations (SS). The sites cover a large area allowing for temporal and spatial characterization of CCN variability in different atmospheric regimes such as marine, continental, boreal, Arctic and Mediterranean environments, boundary layer and free tropospheric conditions. Additionally, autocorrelation analysis is performed to investigate the persistence of variables over different timescales and to explore meaningful averaging periods for global modelling of CCN.

The aerosol populations and their activation behavior show significant differences at the stations. While peak concentrations of CCN are observed in summer at the high altitude sites, in the Arctic the highest concentrations occur during the Haze period in spring. The rural-marine and rural-continental sites exhibit similar CCN concentration characteristics with a relatively flat annual cycle. At some stations, e.g. in the boreal environment, the annual cycle is more pronounced for higher SS. Geometric mean diameters of aerosol populations as well as the activation ratios on the basis of particles > 50 nm vary strongly among sites and throughout the seasons.

In terms of CCN persistence, there are three different regimes: At some sites the autocorrelation drops within a week and shows little seasonal pattern, while at others it remains relatively high for 7 or more days exhibiting also seasonal patterns, and in the third group it has a high correlation for two days and then drops rapidly. Several but not all sites show diurnal cycles.