Estimation of sea level rise and storm surge risks along the coast of Estonia, Baltic Sea – a tool for coastal management

The aim of the paper is to present statistical analysis of the sea level data obtained from the Estonian coastal tide gauges over the period 1842–2009, to assess storm surge risks and to discuss climate change related mitigation and management issues in the coastal zone of Estonia. Long-term variations of both mean and extreme sea level values were studied in the Eastern section of the nearly tideless Baltic Sea. Influenced by postglacial land uplift, the series of relative sea level displayed slightly varying trends. The remarkably steep rise in annual maximum sea levels (2–12 mm/yr) could be explained by the local response to the changing regional wind climate. Due to its windward location, the sea level variations in the semi-enclosed study area are sensitive to the changes in cyclonic activity. Maximum value analysis revealed that in case of the south-westerly exposed Pärnu Bay, two storm surge events (253 in 1967 and 275 cm in 2005) were inconsistent with the theoretical distributions, which indicate that, in some locations, the most extreme sea level events are hardly predictable by means of return statistics. The parameters of maximum expected storm surges were estimated on the basis of hydrodynamic modelling