engleski

Correlation Between Precipitation and Sava River Discharge in Zagreb

We are witnessing an increasing importance of contemporary climate changes. This paper deals with correlation between ammount of precipitation and Sava River discharge at Zagreb. Ljubljana is the representative meteorological station for Sava River discharge investigation in Zagreb. Due to prominent variability of the process the emphasis is on establishing linear trends. In order to reduce the negative characteristics of shifting arithmetic means, only three-year shifting arithmetic means are shown. The increase of annual precipitation amount in Ljubljana leads to increased Sava discharge at Zagreb. Correlation between precipitation and discharge is linear, therefore we have linear correlation. Calculated correlation coefficient is 0.81. Sava river discharge in Zagreb has been recorded since 1926, but due to the break between 1996 and 1998, the existing data from the following few years after the break were not used. There has been a downward trend of Sava discharge at Zagreb since 1926. However, there is a distinct difference between the older period (1926-1959) and the recent one (1960-1995). In the older period there is a big variability of Sava discharge. Three-year shifting arithmetic means also prove it. The recent period is characterized by a decrease of difference in mean annual Sava discharge. Distinct trend in discharge decrease is also very important. Linear trend shows that „linear“ annual discharge between 1960 and 1995 decreased by 118.85 m3/s. That is undoubtedly alarming information.

precipitation; discharge; Sava River; Zagreb; climate

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