Modelling of flows, sea level variations and bottom stresses in the coastal zone of West Estonia

摘要

Flow features and sea level variations were studied in the nearly tideless sub-basins of the Baltic Sea, the Gulf of Riga and the Vaeinameri, using a high-resolution (of order 1 km grid) shallow sea 2D hydrodynamic model. The model is forced by the wind stress calculated from single-point meteorological data, and the tide gauge sea level data applied along the open boundaries. The simulations based both on the realistic and idealistic forcing schemes were carried out. The aim of the study was to analyse circulation patterns during different meteorological conditions and to investigate the influence of currents, waves and sea level fluctuations on the littoral processes. In the Paernu Bay the high flow velocities, participating (along with storm waves) in the coastal erosion events, act 1.5-2 m above the average waterline and about half of the year's summary work is done during the 2-3 most stormy days of the year. In the indented West Estonian coast infrequent storm surges flush the eutrophic ends of the narrow and shallow bays, e.g. the Matsalu Bay, but low wave activity and weak currents cannot either remove muddy deposits of the delta region or import sandy deposits from the nearby Vaeinameri region.