Using discriminant analysis as a nucleation event classification method S. Mikkonen1, K. E. J. Lehtinen1,2, A. Hamed1, J. Joutsensaari3, M. C. Facchini4, and A. Laaksonen1 1Department of Physics, University of Kuopio, P.O. Box 1627, 70211 Kuopio, Finland 2Finnish meteorological institute, Kuopio Unit, P.O. Box 1627, 70210 Kuopio, Finland 3Department of Environmental Sciences, University of Kuopio, P.O. Box 1627, 70211 Kuopio, Finland 4Istituto di Scienze dell'Atmosfera e del Clima – CNR, Italy Via Gobetti 101, 40 129 Bologna, Italy
Abstract. More than three years of measurements of aerosol size-distribution and
different gas and meteorological parameters made in Po Valley, Italy were
analysed for this study to examine which of the meteorological and trace gas
variables effect on the emergence of nucleation events. As the analysis
method, we used discriminant analysis with non-parametric Epanechnikov
kernel, included in non-parametric density estimation method. The best
classification result in our data was reached with the combination of
relative humidity, ozone concentration and a third degree polynomial of
radiation. RH appeared to have a preventing effect on the new particle
formation whereas the effects of O3 and radiation were more conductive.
The concentration of SO2 and NO2 also appeared to have significant
effect on the emergence of nucleation events but because of the great amount
of missing observations, we had to exclude them from the final analysis.
Citation: Mikkonen, S., Lehtinen, K. E. J., Hamed, A., Joutsensaari, J., Facchini, M. C., and Laaksonen, A.: Using discriminant analysis as a nucleation event classification method, Atmos. Chem. Phys., 6, 5549-5557, doi:10.5194/acp-6-5549-2006, 2006.