Abstract
A long record (1887–1975) of daily mean values of the sea level from the Kattegat is analysed. The variance of the sea level is 340 cm2. 60% of this is caused by fluctuations with periods of 2 months and shorter. This high frequency variance changes throughout the year by a factor of 4, with a maximum during early winter.
From the dynamics of the water exchange through the Belts and the Sound a non-linear response function for the Baltic is constructed. Applying this, it is found that the effective barotropically driven water exchange between the Baltic and the Sea is, to about 42%, executed by high-frequency fluctuations (2 months and shorter). It is found that no single 4-year mean of the effective barotropically driven water exchange has deviated by more than about 10% from the mean of the whole period under consideration and that the variations seem to be random.
The amplitudes of some long-period, phase-locked components are determined. Among other things it is found that the I-year period has the largest amplitude, about 10 cm.
