Authors: I. Zaitseva-Pärnaste, T. Soomere and O. Tribštok

The study presents new evidence of large spatial variations in wave properties along the eastern coast of the Baltic Sea. The short-term (1-3 years) interannual variability of the annual mean wave height is almost coherent along the entire eastern coast in 1958-1986. This
coherence is completely lost from about 1987: since then the annual mean wave height at Narva-Jõesuu is in anti-phase with this height in the Baltic Proper. Also, in 1954-1957 the mean wave height in the eastern part of the Baltic Proper gradually decreases but rapidly
increases in the Gulf of Finland. The decadal course of wave activity match relatively well each other at Nida and Vilsandi until about 1992, after which the annual mean wave height behavior is completely different at these sites. The largest difference between the long-term course in the wave height is found between Vilsandi (where the wave activity increases by a factor of two in 1987-1997 and decreases even more since then) and Narva-Jõesuu (where the wave activity gradually decreases over the entire observation period).