Decadal variations in mean and extreme sea level values along the Estonian coast of the Baltic Sea

Abstract

This study presents an overview of the Estonian sea level data set obtained from the coastal tide gauges over the period 1842–2005. Variations in the time‐series of annual mean sea level, maxima and minima, as well as standard deviations are investigated and their relationships with variations in the North Atlantic Oscillation index are studied. After correcting the sea level series to spatially varying land uplift rates the series display increasing (1.5–2.7 mm yr−1) trends, which in case of Pärnu tide gauge evidently exceed the global sea level rise rate. The increase is larger in winter, which is in accordance with similar seasonal structures of the NAO index trends. The rise in mean sea level, standard deviations and particularly in maxima (3.5–11.2 mm yr−1) 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 ongoing intensification of cyclones and prevailing westwinds. In case of the Pärnu Bay, the statistical fit of both the frequency distributions of hourly data and the maximum values distributions for 1923–2005 are inconsistent with the two highest storm surge values of 253 and 275 cm.

Recent Change—Sea Level and Wind Waves

“…Studies at the Estonian coastline showed a remarkable rise in annual sea level maxima of 3.5-11 mm year −1 after correcting for local uplift rates (Vallner et al 1988;Suursaar and Sooäär 2007). Even excluding the prominent event of 2005, the rise in annual sea level maxima was significantly higher than the rise in MSL (1-2.6 mm year −1 ) and the rise in annual sea level minima (0.8-3.1 mm year −1 ).…”

“…The correlation between the NAO and Baltic Sea sea level is especially strong in winter (e.g. Andersson 2002;Dailidienė et al 2006;Hünicke and Zorita 2006;Suursaar and Sooäär 2007), and in northern and eastern parts of the Baltic Sea Suursaar et al 2006a) (see Fig. 9.4, right panel).…”

“…Tide gauge operation, and the processing, distribution and archiving of the data are the responsibility of a single national agency per country, for instance the Swedish Meteorological and Hydrographical Institute (SMHI), the Danish Meteorological Institute (DMI), the Estonian Meteorological and Hydrographical Institute (EMHI), the Finnish Barbosa et al (2008) Baltic Sea basin wide Omstedt and Nyberg (1991), Heyen et al (1996), Carlsson (1997Carlsson ( , 1998aCarlsson ( , 1998b, Liebsch (1997), Janssen (2002), Baerens et al (2003), Meier et al (2004), Novotny et al (2006), Hünicke and Zorita (2006, 2007, 2008, Barbosa (2008), , Ekman (2009) and references therein; Hünicke (2010), Donner et al (2012) Southern Baltic Sea coast Richter et al (2007Richter et al ( , 2011 Lithuania Dailidienė et al (2004Dailidienė et al ( , 2005Dailidienė et al ( , 2006Dailidienė et al ( , 2011Dailidienė et al ( , 2012, Jarmalavicius et al (2007) Russia Bogdanov et al (2000), Averkiev and Klevannyy (2010), Navrotskaya and Chubarenko (2012) Estonia Suursaar et al (2002Suursaar et al ( , 2006aSuursaar et al ( , 2010, Kullas (2006, 2009b), Suursaar and Sooäär (2007), Suursaar (2010), Tõnisson et al (2011) Poland Zawadzka (2005, 2008), Richter et al (2007…”

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

“…The plots of empirical return periods against the corresponding theoretical (e.g. Gumbel) distributions [Suursaar and Sooäär, 2007] showed a more or less a satisfactory fit in all cases except Pärnu maxima. No extreme value distributions could probably describe or predict the two extreme sea level events of 253 cm or 275 cm (Fig.…”

“…According to the data published by Bogdanov et al [2000], the mean was 5.9 cm in 1971-1993. Instead, the mean sea level of Estonian tide gauges is roughly around the Kronstadt zero now [Suursaar and Sooäär, 2007].…”