Articles | Volume 18, issue 1
https://doi.org/10.5194/os-18-89-2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/os-18-89-2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
19 Jan 2022
Research article |
| 19 Jan 2022
| 19 Jan 2022
Refined estimates of water transport through the Åland Sea in the Baltic Sea
Finnish Meteorological Institute, Marine Research, Erik Palménin aukio 1, P.O. Box 503, 00101 Helsinki, Finland
Elina Miettunen
Finnish Environment Institute SYKE, Marine Research Centre, Latokartanonkaari 11, 00790 Helsinki, Finland
Laura Tuomi
Finnish Meteorological Institute, Marine Research, Erik Palménin aukio 1, P.O. Box 503, 00101 Helsinki, Finland
Pekka Alenius
Finnish Meteorological Institute, Marine Research, Erik Palménin aukio 1, P.O. Box 503, 00101 Helsinki, Finland
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Cited articles
Ahlgren, J., Grimvall, A., Omstedt, A., Rolff, C., and Wikner, J.: Temperature, DOC level and basin interactions explain the declining oxygen concentrations in the Bothnian Sea, J. Marine Syst., 170, 22–30, https://doi.org/10.1016/j.jmarsys.2016.12.010, 2017. a
CMEMS: Baltic Sea Physics Reanalysis, CMEMS [data set],
https://doi.org/10.48670/moi-00013, 2022. a
FMI: The Finnish Meteorological Institute's open data, FMI, available at:
https://en.ilmatieteenlaitos.fi/open-data, last access: 4 January 2022. a
Fringer, O. B., Dawson, C. N., He, R., Ralston, D. K., and Zhang, Y. J.: The future of coastal and estuarine modeling: Findings from a workshop, Ocean Model., 143, 101458, https://doi.org/10.1016/j.ocemod.2019.101458, 2019. a
Granqvist, G.:
Baltianmeren lämpötila ja suolaisuus Suomen rannikolla,
Merentutkimuslaitoksen julkaisuja, 1–64, 1938. a
Hela, I.: The Åland Sea, its surface topography and stationary currents, Geophysica, 13, 17–41, 1973. a
Hersbach, H., Bell, B., Berrisford, P., Biavati, G., Horányi, A., Muñoz Sabater, J., Nicolas, J., Peubey, C., Radu, R., Rozum, I., Schepers, D., Simmons, A., Soci, C., Dee, D., and Thépaut, J.-N.: ERA5 hourly data on single levels from 1979 to present, Copernicus Climate Change Service (C3S) Climate Data Store (CDS) [data set], https://doi.org/10.24381/cds.adbb2d47, 2018. a, b
Hordoir, R., Axell, L., Höglund, A., Dieterich, C., Fransner, F., Gröger, M., Liu, Y., Pemberton, P., Schimanke, S., Andersson, H., Ljungemyr, P., Nygren, P., Falahat, S., Nord, A., Jönsson, A., Lake, I., Döös, K., Hieronymus, M., Dietze, H., Löptien, U., Kuznetsov, I., Westerlund, A., Tuomi, L., and Haapala, J.: Nemo-Nordic 1.0: a NEMO-based ocean model for the Baltic and North seas – research and operational applications, Geosci. Model Dev., 12, 363–386, https://doi.org/10.5194/gmd-12-363-2019, 2019. a, b
Huttunen, I., Huttunen, M., Piirainen, V., Korppoo, M., Lepistö, A., Räike, A., Tattari, S., and Vehviläinen, B.: A National-Scale Nutrient Loading Model for Finnish Watersheds—VEMALA, Environ. Model. Assess., 21, 83–109, https://doi.org/10.1007/s10666-015-9470-6, 2016. a
Jakobsson, M., Stranne, C., O'Regan, M., Greenwood, S. L., Gustafsson, B., Humborg, C., and Weidner, E.: Bathymetric properties of the Baltic Sea, Ocean Sci., 15, 905–924, https://doi.org/10.5194/os-15-905-2019, 2019. a
Kärnä, T., Ljungemyr, P., Falahat, S., Ringgaard, I., Axell, L., Korabel, V., Murawski, J., Maljutenko, I., Lindenthal, A., Jandt-Scheelke, S., Verjovkina, S., Lorkowski, I., Lagemaa, P., She, J., Tuomi, L., Nord, A., and Huess, V.: Nemo-Nordic 2.0: operational marine forecast model for the Baltic Sea, Geosci. Model Dev., 14, 5731–5749, https://doi.org/10.5194/gmd-14-5731-2021, 2021. a
Klingbeil, K., Lemarié, F., Debreu, L., and Burchard, H.: The numerics of hydrostatic structured-grid coastal ocean models: State of the art and future perspectives, Ocean Model., 125, 80–105, https://doi.org/10.1016/j.ocemod.2018.01.007, 2018. a, b
Knudsen, M.: Ein
hydrographischer Lehrsatz, Annalen der Hydrographie und Maritimen
Meteorologie, 28, 316–320, 1900 (in German). a
Kuosa, H., Fleming-Lehtinen, V., Lehtinen, S., Lehtiniemi, M., Nygård, H., Raateoja, M., Raitaniemi, J., Tuimala, J., Uusitalo, L., and Suikkanen, S.: A retrospective view of the development of the Gulf of Bothnia ecosystem, J. Marine Syst., 167, 78–92, https://doi.org/10.1016/j.jmarsys.2016.11.020, 2017. a
Leppäranta, M. and Myrberg, K.: Physical oceanography of the Baltic Sea, Springer Verlag, Berlin, Heidelberg, New York, 2009. a
Lignell, R., Miettunen, E., Tuomi, L., Ropponen, J., Kuosa, H., Attila, J., Puttonen, I., Lukkari, K., Peltonen, H., Lehtoranta, J., Huttunen, M., Korppoo, M., Tikka, K., Mäyrä, J., Heiskanen, A.-S., Gustafsson, B., Gustafsson, E., Hänninen, J., Thingstad, F., Kaurila, K., Vanhatalo, J.,
Westerlund, A., and Siiriä, S.-M.: Rannikon kokonaiskuormitusmalli: ravinnepäästöjen vaikutus veden tilaan – Kehityshankkeen loppuraportti (XI 2015 – VI 2018), available at:
https://www.ym.fi/download/noname/%7BD5C68F2D-D52B-4C73-9E0B-FE53C5FFD207%7D/142893
(last access: 4 January 2022), 2018. a
Lisitzin, E.: A brief report on the scientific results of the hydrological expedition to the Archipelago and Åland Sea in the year 1922, Fennia 73, 4, Societas geographica Fenniae, Helsinki, 1951. a
Luyten, P.: COHERENS – A Coupled Hydrodynamical-Ecological Model for Regional and Shelf Seas: User Documentation, Version 2.5.1, RBINS-MUMM Report, Royal Belgian Institute of Natural Sciences, Brussels, Belgium, 2013. a
Madec, G. and NEMO System Team: NEMO ocean engine, Zenodo [code], https://doi.org/10.5281/zenodo.1464816, 2019. a, b
McWilliams, J. C.: A survey of submesoscale currents, Geosci. Lett., 6, 3, https://doi.org/10.1186/s40562-019-0133-3, 2019. a
Miettunen, E., Tuomi, L., and Myrberg, K.: Water exchange between the inner and outer archipelago areas of the Finnish Archipelago Sea in the Baltic Sea, Ocean Dynam., 70, 1421–1437, https://doi.org/10.1007/s10236-020-01407-y, 2020. a, b, c
Rutgersson, A., Bumke, K., Clemens, M., Foltescu, V., Lindau, R., Michelson, D., and Omstedt, A.: Precipitation Estimates over the Baltic Sea: Present State of the Art, Hydrol. Res., 32, 285–314, https://doi.org/10.2166/nh.2001.0017, 2001. a
Smagorinsky, J.: General Circulation Experiments with the Primitive Equations. The Basic Experiment, Mon. Weather Rev., 91, 99–164, https://doi.org/10.1175/1520-0493(1963)091<0099:GCEWTP>2.3.CO;2, 1963. a
SYKE: Open information, SYKE, available at: https://www.syke.fi/en-US/Open_information, last access: 4 January 2022. a
Vankevich, R. E., Sofina, E. V., Eremina, T. E., Ryabchenko, V. A., Molchanov, M. S., and Isaev, A. V.: Effects of lateral processes on the seasonal water stratification of the Gulf of Finland: 3-D NEMO-based model study, Ocean Sci., 12, 987–1001, https://doi.org/10.5194/os-12-987-2016, 2016. a
Westerlund, A. and Miettunen, E.: nemo-archs, FMI [code],
https://github.com/fmidev/nemo-archs (last access: 4 January 2022), 2021. a
Westerlund, A. and Tuomi, L.: Vertical temperature dynamics in the Northern Baltic Sea based on 3D modelling and data from shallow-water Argo floats, J. Marine Syst., 158, 34–44, https://doi.org/10.1016/j.jmarsys.2016.01.006, 2016.
a, b
Westerlund, A., Tuomi, L., Alenius, P., Miettunen, E., and Vankevich, R. E.: Attributing mean circulation patterns to physical phenomena in the Gulf of Finland, Oceanologia, 60, 16–31, https://doi.org/10.1016/j.oceano.2017.05.003, 2018. a, b, c
Westerlund, A., Tuomi, L., Alenius, P., Myrberg, K., Miettunen, E., Vankevich, R. E., and Hordoir, R.: Circulation patterns in the Gulf of Finland from daily to seasonal timescales, Tellus A, 71, 1627149, https://doi.org/10.1080/16000870.2019.1627149, 2019. a, b
Witting, R.: Untersuchungen
zur Kenntnis der Wasserbewegugen und der Wasserumsetzung in
den Finland umgebenden Meeren, Finländische
Hydr.-Biol. Untersuchungen, 1908 (in German). a
Zhurbas, V. M., Laanemets, J., Kuzmina, N. P., Muraviev, S. S., and Elken, J.: Direct estimates of the lateral eddy diffusivity in the Gulf of Finland of the Baltic Sea (based on the results of numerical experiments with an eddy resolving model), Oceanology, 48, 175–181, https://doi.org/10.1134/S0001437008020033, 2008. a
Short summary
Water exchange through the Åland Sea (in the Baltic Sea) affects the conditions in the neighbouring Gulf of Bothnia. Pathways and variability of flows were studied with a high-resolution hydrodynamic model. Our analysis showed a northward transport in the deep layer and net transport towards the south in the surface layer. While on the southern edge of the Åland Sea the primary route of deep-water exchange is through Lågskär Deep, some deep water still bypasses it to the Åland Sea.
Water exchange through the Åland Sea (in the Baltic Sea) affects the conditions in the...
