Elementarne podejście do problemu cykliczności w zjawiskach klimatycznych

The paper presents an elementary approach to the problem of periodicity in climatic data. The basic method applied in this study is the Fourier analysis (FFT). The periodicity was searched on the basis of long term instrumental precipitation data for 46 European stations for the period of 1832-1992, and for W-E and N-E transects for the period 1864-1992. The evidence of cycles in the range 2 to 128 years was examined in terms of their being of natural variability of climate system, or the result of external forcing. The complexity of the climate system with large number of degrees of freedom, and the unstable nature of atmospheric circulation causing difficulties in distinguish real periodicity from noise. The result show that it is relatively easy to obtain quasi-periodicity in climatic data however it is very difficult to find them statistically significant. We can said that disturbances in climate system can produce a quasi-periodic response which behaves sometimes as an oscillation before disappearing back into the noise or appearing in other place and other time.