engleski

Stationarity, trend and periodicity of precipitation at Zagreb-Grič observatory from 1862 to 1990

this paper deals with the climatic change in the annual, warm half-year and cold half-year precipitation data during the last 129 years, since the begining of the series in the 1862 to 1990, at the Zagreb-grič observatory (45°49'N, 15°59'E, 159 m asl)located in the north-western part of Croatia. The analysis has been deduced by using test for normality, the quick test for stationarity according to Schoenwiese and malcher, weighted moving average filters, the mann-kendall rank statistic for trend, and the power spectrum analysis. The analysis shows the stationarity of time series of precipitation amounts. A generally decreasing, not statisticaly significant trend is present over the entire time interval (1862-1990). The annual and the waem half-year precipitation spectra ca be fitted by Markov "red noise" continuum and the cold half-year precipitation series by that of "white noise". Quasi-periodic ascillations appear in two spectra ranges: short (2-6 years) and medium (16-43 years).

precipitation; stationarity; trend; periodicity; power spectrum; Zagreb; Croatia

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