Author(s)

T. Soomere, K. Rannat, J. Elken & K. Myrberg

Abstract

Natural and anthropogenic wave forcing in the Tallinn Bay, Baltic Sea T. soomere', K. ~annat', J. ~lken' & K. ~ y - b e r ~ ~ 1 Marine Systems Institute, Tallinn Technical University, Estonia 2~innish Institute of Marine Research, Finland Abstract The Tallinn Bay is a 10x20-km semi-enclosed area of the Gulf of Finland. Since tidal currents are negligible in this area, wind waves and local currents that both cause moderate near-bottom velocities off shoreline govern the beach processes. In recent years, high-speed ship traffic has increased considerably and amounts to 70 traverse per day. The ships frequently sail with speeds close to the critical velocity. Comparison of a long-term reconstruction of wind wave climate with the direct ship wave measurement shows that, in the coastal zone of the bay the mean energy of ship waves is 7-10% from the bulk wave energy and waveinduced power as high as 40% from the bulk wave power. The annual maximum of significant wind wave heights is frequently 4 . 5 m

Keywords