Long-term changes in the parameters of the sea ice regime (the date of appearance of the first sea ice in the beginning of winter, the date of the formation of fast ice, the date of the formation of young ice, the date of the break-up of fast ice, the date of the final disappearance of sea ice and the total number of days with sea ice) in the Baltic Sea near the Estonian coast are analysed for the period 1950/1951–2004/2005. Data were obtained from 8 stations at different coastal regions. Medians, quartile ranges and extremes were calculated. Spatial differences in the sea ice regime between different coastal regions of Estonia were determined. A statistically significant decrease in sea ice was detected that lies in a good correlation with the general warming trend in winter and spring during the same period. Large differences in the magnitude of the trends can be found between different coastal regions of Estonia. On the southern coast of the Gulf of Finland, long-term changes in sea ice parameters are small and mostly insignificant. The highest decrease in sea ice has been observed on the islands of the West-Estonian Archipelago, where the period with ice has decreased by 1.5–2.5 months. Possible causes for the spatial differences are discussed.
1. Jaagus, J. Climatic changes in Estonia during the second half of the 20th century in relationship with changes in large-scale atmospheric circulation. Theor. Appl. Climatol., 2006, 83, 77–88.
2. Mardiste, H. Ice conditions in the Väinameri and their influence on the traffic between West-Estonian islands and the mainland. Publ. Inst. Geogr. Univ. Tartuensis, 1999, 84, 37–42.
3. Tarand, A. and Nordli, P. Ø. The Tallinn temperature series reconstructed back half a millennium by use of proxy data. Clim. Change, 2001, 48, 189–199.
4. Vahter, R. Tallinna ja Muuga lahe jääolud. Eesti Geograafia Seltsi aastaraamat, 1994, 26, 19–30.
5. Jaagus, J. Interactions between snow cover duration, extent of sea ice and winter mean air temperature in Estonia. Publ. Inst. Geogr. Univ. Tartuensis, 1999, 84, 74–83.
6. Tooming, H. and Keevallik, S. Relationships among the ice extent on the Baltic Sea, the snow cover in surrounding areas, and the temperature. In Proc. Third Study Conference on BALTEX. 2001. International BALTEX Secretariat, 2001, Publication No. 20, 229–230.
7. Jevrejeva, S. Long-term variability of sea ice and air temperature conditions along the Estonian coast. Geophysica, 2000, 36, 17–30.
8. Jevrejeva, S. Severity of winter seasons in the northern Baltic Sea between 1529 and 1990: reconstruction and analysis. Clim. Res., 2001, 17, 55–62.
9. Jevrejeva, S. Association between the ice conditions in the Baltic Sea and the North Atlantic Oscillation. Nord. Hydrol., 2002, 33, 319–330.
10. Jevrejeva, S. and Leppäranta, M. Ice conditions along the Estonian coast in a statistical view. Nord. Hydrol., 2002, 33, 241–262.
11. Jevrejeva, S. and Moore, J. C. Singular spectrum analysis of Baltic Sea ice conditions and large-scale atmospheric patterns since 1708. Geophys. Res. Lett., 2003, 28, 4503–4507.
12. Jevrejeva, S. Freezing and break-up on the Baltic Sea along the Estonian coast 1890–1990. In Proc. Third Workshop on Baltic Sea Ice Climate. Stawiska, Poland, 1999, 47–52.
13. Jevrejeva, S., Moore, J. C. and Grinsted, A. Influence of the Arctic Oscillation and El Niño-Southern Oscillation (ENSO) on ice conditions in the Baltic Sea: the wavelet approach. J. Geophys. Res., 2003, 108(D21), 4677.
14. Jaagus, J. Muutused Eesti rannikumere jääoludes 20. sajandi teisel poolel. Publ. Inst. Geogr. Univ. Tartuensis, 2003, 93, 143–152.
15. Jaagus, J. Trends in sea ice conditions on the Baltic Sea near the Estonian coast during the period 1949/50–2003/04 and their relationships to large-scale atmospheric circulation. Boreal Env. Res., 2006, 11, 169–183.
