Time-Series Analysis of Isotope Composition of Precipitation in Zagreb, Croatia

Air temperature and precipitation data (1976-2021), stable isotope composition (delta O-18, delta H-2) data, and deuterium excess (1980-2021) data were analyzed using principal component analysis (PCA), Fourier analysis (FA), and wavelet analysis (WA). The PCA represented each month by a single dot in the diagram, and month 1 and month 7 were clearly distinguished. The FA and WA gave the 12-month period for all parameters, but the strongest power was for temperature, then delta O-18 and delta H-2, and finally for the precipitation amount and deuterium excess. Both Pearson's r and Spearman's rho correlation coefficients gave similar values for delta H-2-delta O-18 and temperature-delta H-2, delta O-18 correlations.

Automated summary

Principal component analysis, Fourier analysis, and wavelet analysis were used to analyze the correlation and seasonal variations among air temperature, precipitation, and stable isotope data. The results showed significant relationships and seasonal patterns.