In the paper a barotropic model of continental shelf waves with sloping depth of finite width without depth-break at the edge of the shelf is adopted for the region of the eastern part of the Baltic Proper. The dispersion relations and the distribution of the amplitudes of coastal-trapped waves are calculated. It is shown that dispersion relation is stable relative to the characteristic length scale. It was found that shorter waves are more strongly trapped by the coastline. Dispersion curves and the distribution of wave amplitudes are similar to the continental shelf waves in the ocean. The inhomogenities of the scale of 15 km on the water surface in the satellite images may be the result of low-frequency coastal-trapped waves. The current measurements, carried out in the Irbe Strait in June 1995, showed the existence of current oscillations with a period of 44 hours. The model results allow to pose the hypothesis that these oscillations are coastal-trapped waves generated by wind stress variability in the eastern Baltic, from where they propagate northward into the Irbe Strait.
1. LeBlond, P. H. and Mysak, L. A. Waves in the Ocean. Elsevier, Amsterdam, 1978.
2. Mysak, L. A. Recent advances in shelf dynamics. Rev. Geophys. Space Phys., 1980, 18, 211–241.
3. Kamenkovitch, V. M. and Monin, A. C. Oceanology, vol. 2. Nauka, Moscow, 1978 (in Russian).
4. Talpsepp, L. On trapped topographic waves in the Baltic Sea. Oceanology, 1983, 23, 928–931 (in Russian).
5. Pizarro, O. and Shaffer, G. Wind-driven, coastal-trapped waves off the island of Gotland, Baltic Sea. J. Phys. Oceanogr., 1998, 28, 2117–2129.
6. Raudsepp, U., Beletsky, D. and Schwab, D. Basin-scale topographic waves in the Gulf of Riga. J. Phys. Oceanogr., 2003, 33, 1129–1140.
7. Mysak, L. A. Edgewaves on a gently sloping continental shelf of finite width. J. Mar. Res., 1968, 26, 24–33.
8. Bychkova, I. and Viktorov, S. Use of satellite data for identification and classification of upwelling in the Baltic Sea. Oceanology, 1986, 27, 158–162 (in Russian).
9. Kahru, M. and Leppänen, J.-M. Cyanobacteria blooms in the Gulf of Finland triggered by saltwater inflow into the Baltic sea. Mar. Ecol. Progr. Series, 2000, 207, 13–18.
10. Lass, H. U. and Talpsepp, L. Observations of coastal jets in the Southern Baltic. Cont. Shelf Res., 1983, 13, 189–203.
11. Talpsepp, L. Coherent current oscillations and water exchange in the straits of the Gulf of Riga. Oceanologia, 2005, 47, 115–127.
12. Lilover, M.-J., Lips, U., Laanearu, J. and Liljebladh, B. Flow regime in the Irbe Strait. Aquat. Sci., 1998, 60, 1–13.
13. Talpsepp, L. and Laanearu, J. Eulerian current measurements by RCM-7. In Estonian Marine Institute Report Series, 1995, No. 2. EMI, Tallinn, 69–77.
14. Otsmann, M., Astok, V. and Suursaar, Ü. A model for water exchange between Baltic Sea and the Gulf of Riga. Nord. Hydrol., 1997, 28, 351–364.
15. Tomczak, M. Introduction to the Oceanography. 2004, http://www.es.flinders.edu.au/~mattom/ IntroOc/lecture10.html
