Trajectory analysis of atmospheric transport of fine particles, SO 2, NOx and O3 to the SMEAR II station in Finland in 1996-2008
Trajectory statistical methods that combine in situ measurements of\ntrace gas or particle concentrations and back trajectories calculated\nfor corresponding times have proven to be a valuable approach in\natmospheric research; especially in investigating air pollution\nepisodes, but also in e. g. tracing the air mass history related to high\nvs. low concentrations of aerosol particles of different sizes at the\nreceptor site. A concentration field method was fine-tuned to take the\npresumable horizontal error in calculated trajectories into account,\ntested with SO2 and validated by comparison against EMEP (European\nMonitoring and Evaluation Programme) emission data. In this work we\napply the improved method for characterizing the transport of\natmospheric SO2, NOx, O-3 and aerosol particles of different size modes\nto a Finnish measurement station located in Hyytiala (61 degrees 51' N,\n24 degrees 17' E). Our method did not reproduce the EMEP emission\nsoures, but proved useful for qualitative analysis on where the measured\ncompounds come from, from one measurement station point of view. We\napplied it to study trends and seasonal variation in atmospheric\npollutant transport during 13 yr at the SMEAR II (Station for Measuring\nEcosystem-Atmosphere Interactions) station.