Some characteristics of climatic change at Zagreb during the last thirty years

On the basis of changes in the seasonal variations of pressure, precipitation and temperaturte at the Zagreb-Grič Observatory in the 1862 – 1980 period, we can distinguish four periods of an approximate duration of thirty years each, within which seasonal variations of climatic elements show some specific characteristics. Periods with somewhat stronger characteristics of continental climate (1862– 1890, 1920– 1950) alternate with periods during which continental characteristics are considerably weakened (1890– 1920, 1951– 1980). As a consequence of these climatic oscillations, it has been pointed out that the climatological normals determined on the basis of 30-year record are not necessarily reliable. The relative significance of these climatological fluctuations has been estimated on the basis of comparisons with spatial variations of previously used indicators in the area of Northern Croatia, which can be considered as an area with a uniform climate. The comparisons have shown that although the temporal variations of the climatic characteristics of Zagreb (and probably even a wider area) are relatively small, they cannot be neglected