1Department of Physics, University of Helsinki, P.O. Box 64, 00014 University of Helsinki, Helsinki, Finland
2Helsinki Institute of Physics, P.O. Box 64, 00014 University of Helsinki, Helsinki, Finland
3Finnish Meteorological Institute, Climate Change Unit, 00101 Helsinki, Finland
4Lund University, Department of Physics, Lund, 22100 Lund, Sweden
5Tampere University of Technology, Dept. of Physics, P.O. Box 692, 33101 Tampere, Finland
6Department of Physical Geography and Ecosystems Science, Sölvegatan 12, 223 62 Lund, Sweden
7Karlsruher Institute of Technology, Instute of Meteorology and Climate Research/Atmospheric Environmental Research (IMK-IFU), Kreuzeckbahnstr. 19, 82467 Garmisch-Partenkirchen, Germany
Abstract. We investigated atmospheric aerosol particle dynamics in a boreal forest zone in northern Scandinavia. We used aerosol number size distribution data measured with either a differential mobility particle sizer (DMPS) or scanning mobility particle sizer (SMPS) at three stations (Värriö, Pallas and Abisko), and combined these data with the HYSPLIT (Hybrid Single Particle Lagrangian Integrated Trajectory) air mass trajectory analysis. We compared three approaches: analysis of new particle formation events, investigation of aerosol particle number size distributions during the air mass transport from the ocean to individual stations with different overland transport times, and analysis of changes in aerosol particle number size distributions during the air mass transport from one measurement station to another. Aitken-mode particles were found to have apparent average growth rates of 0.6–0.7 nm h−1 when the air masses traveled over land. Particle growth rates during the new particle formation (NPF) events were 3–6 times higher than the apparent particle growth during the summer period. When comparing aerosol dynamics for different overland transport times between the different stations, no major differences were found, except that in Abisko the NPF events were observed to take place in air masses with shorter overland times than at the other stations. We speculate that this is related to the meteorological differences along the paths of air masses caused by the land surface topology. When comparing air masses traveling in an east-to-west direction with those traveling in a west-to-east direction, clear differences in the aerosol dynamics were seen. Our results suggest that the condensation growth has an important role in aerosol dynamics even when NPF is not evident.