Seasonal variation of atmospheric particle number concentrations, new particle formation and atmospheric oxidation capacity at the high Arctic site Villum Research Station, Station Nord
- 1Department of Environmental Science, Aarhus University, 4000 Roskilde, Denmark
- 2Department of Chemistry, Aarhus University, 8000 Aarhus, Denmark
- 3Department of Engineering, Aarhus University, 8200 Aarhus, Denmark
- 4Interdisciplinary Nanoscience Center (iNANO), Aarhus University, 8000 Aarhus, Denmark
- 5Institute of Chemical Engineering and Biotechnology and Environmental Technology, University of Southern Denmark, 5230 Odense, Denmark
- 6Arctic Research Centre, Aarhus University, 8000 Aarhus, Denmark
- 7Leibniz Institute for Tropospheric Research, 04318 Leipzig, Germany
- 8Department of Physics, Lund University, P.O. Box 118, 221 00 Lund, Sweden
Abstract. This work presents an analysis of the physical properties of sub-micrometer aerosol particles measured at the high Arctic site Villum Research Station, Station Nord (VRS), northeast Greenland, between July 2010 and February 2013. The study focuses on particle number concentrations, particle number size distributions and the occurrence of new particle formation (NPF) events and their seasonality in the high Arctic, where observations and characterization of such aerosol particle properties and corresponding events are rare and understanding of related processes is lacking.
A clear accumulation mode was observed during the darker months from October until mid-May, which became considerably more pronounced during the prominent Arctic haze months from March to mid-May. In contrast, nucleation- and Aitken-mode particles were predominantly observed during the summer months. Analysis of wind direction and wind speed indicated possible contributions of marine sources from the easterly side of the station to the observed summertime particle number concentrations, while southwesterly to westerly winds dominated during the darker months. NPF events lasting from hours to days were mostly observed from June until August, with fewer events observed during the months with less sunlight, i.e., March, April, September and October. The results tend to indicate that ozone (O3) might be weakly anti-correlated with particle number concentrations of the nucleation-mode range (10–30 nm) in almost half of the NPF events, while no positive correlation was observed. Calculations of air mass back trajectories using the Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model for the NPF event days suggested that the onset or interruption of events could possibly be explained by changes in air mass origin. A map of event occurrence probability was computed, indicating that southerly air masses from over the Greenland Sea were more likely linked to those events.