Long-Term Variability Pattern of Monthly and Annual Atmospheric Precipitation in the Polish Carpathian Mountains and Their Foreland (1881–2018)

Abstract

This study focuses on demonstrating the multiannual patterns of cyclical fluctuations of monthly and annual precipitation in the Polish Carpathian Mountains and their foreland. The study is based on secular series of precipitation totals from 18 meteorological stations for the 138-year period from 1881 to 2018. Use is made of Fourier analysis (FFT) and wavelet transform nonlinear estimation. The study has found a 35-year Bruckner cycle in annual precipitation across the area. The number of days during the year with the types of cyclonic circulation that lead to extremely high precipitation, i.e. with the northerly and north-easterly (Nc + NEc) types and a cyclonic trough (Bc), is not clearly correlated with the 35-year harmonic variability derived from annual precipitation totals. However, the Fourier transform demonstrates a local maximum at T = 35 years. A harmonic 6-month cycle has been discovered as the only harmonic cycle in monthly precipitation. Its stability over the 138-year timespan is investigated.