Application of factor analysis for quantification of climate-forming processes in the eastern part of the Baltic Sea region

Factor analysis (FA) is applied to identify climate-forming factors and quantitatively evaluate their importance in the eastern part of the Baltic Sea region. Monthly data from 7 meteorological stations are used: average maximum and average minimum of air temperature (T-1 and T-2), atmospheric pressure (P), wind speed at a height of 10 m (v), monthly precipitation (Q), duration of sunshine (S) and partial pressure of water vapour (e). FA reveals that the variables form 2 main groups (meteorological complexes): a hygrothermal complex-T-1, T-2 and e-and a baric-radiational complex-P, Q and S. Both meteorological complexes exist almost independently of each other (in cold seasons in particular), i.e. it is possible to distinguish the 2 most important types of climate-forming processes in the eastern part of the Baltic Sea region, One of them is advection related to the input of various air masses whose features are best reflected by air temperature and humidity. The other process mostly takes place within 1 pressure system (cyclone or anticyclone): air mass transformation, vertical mixing, formation of clouds and related precipitation and input of solar radiation.