Vízügyi Közlemények, 1983 (65. évfolyam)

3. füzet - Rövidebb tanulmányok, közlemények, beszámolók

M akroszinoptikus tényezők a Duna vízjárásában 451 Macrosynoptic effects on the flow regime of the Danube River by B. NOVÂ

К Y The macrosynoptic changes taking place in the northern regions of the Atlantic are observed by the meteorological vessels shown in Fig. 1. These data show the Iceland atmospheric low pressure area to have weakened and shifted SW in the period 1947-1966. This has triggered changes in the pattern of ocean currents and water temperatures alike (Fig. 2). Since the water regime of the Danube is influenced by the movement of air- and vapour masses originating from this region of the Atlantic, correlation techniques have been adopted as the main approach in checking whether the annual mean streamflow through the Nagymaros gaging section on the Danube is influenced by the water temperature in the ocean or not. The analysis has been performed by moving averages extending to five years. Bi-variate correlations failed to produce close enough results, but by including the temperature data series of two offshore stations in the Atlantic (stations С and A), a close correlation could be derived. Eqs. ( 1 ) and (2). The streamflows calculated by the relationships are compared with those actually observed in Fig. 3. The results of this study are believed to allow further conclusions to be drawn on the correlation between these changes and the observed periodicities of the water regime. * * *