Winter upwelling in the Gulf of Finland, Baltic Sea
Traditionally, upwelling-related studies in the Baltic Sea have been limited to the period from May to September. Based on wintertime in situ measurements at two nearshore locations in the Gulf of Finland, clear evidence of winter “warm” upwelling events was detected and analysed. The process was ve...
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| Format: | Article |
| Language: | English |
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Elsevier
2021-07-01
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| Series: | Oceanologia |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S0078323421000361 |
| _version_ | 1818884111176040448 |
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| author | Ülo Suursaar |
| author_facet | Ülo Suursaar |
| author_sort | Ülo Suursaar |
| collection | DOAJ |
| description | Traditionally, upwelling-related studies in the Baltic Sea have been limited to the period from May to September. Based on wintertime in situ measurements at two nearshore locations in the Gulf of Finland, clear evidence of winter “warm” upwelling events was detected and analysed. The process was very common. At a 10 m deep location, upwelling caused water temperature (T) to switch from 0–1 to 4–5°C and salinity (S) to switch from 4.5 to 6 PSU; at 20 m depth it caused a switch in T between 1 and 2–4°C and in S between 5.5 and 6.8 PSU. Differently from summer upwelling, T and S variations were positively correlated to each other. Salinity variations remained roughly the same throughout the winter, whereas T differences were higher in winter onset, then decreased to ca. 1°C, and increased again after the process reversed to summer-type upwelling in April–May. Based on analysis of SatBaltyk (January to March) sea surface temperature and salinity product imagery, winter upwelling occurrence along the North Estonian coast was 21–28% over 2010–2021, and slightly less along the Finnish coast. Regarding S variations, winter upwelling occurred with roughly similar frequencies and impacts in the northern and southern parts of the gulf. However, the impacts on T and sea ice conditions were highly asymmetrical. Upwelling kept the Estonian coast ice-free longer and water temperatures slightly higher than at the Finnish coast. Winter upwelling as a phenomenon has long been ignored and therefore probably underestimated. |
| first_indexed | 2024-12-19T15:44:21Z |
| format | Article |
| id | doaj.art-7a8d3e808438483cbb82486babf7b5c1 |
| institution | Directory Open Access Journal |
| issn | 0078-3234 |
| language | English |
| last_indexed | 2024-12-19T15:44:21Z |
| publishDate | 2021-07-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Oceanologia |
| spelling | doaj.art-7a8d3e808438483cbb82486babf7b5c12022-12-21T20:15:23ZengElsevierOceanologia0078-32342021-07-01633356369Winter upwelling in the Gulf of Finland, Baltic SeaÜlo Suursaar0Corresponding author at: University of Tartu, Estonian Marine Institute, Mäealuse 14, 12618 Tallinn, Estonia.; University of Tartu, Estonian Marine Institute, Tallinn, EstoniaTraditionally, upwelling-related studies in the Baltic Sea have been limited to the period from May to September. Based on wintertime in situ measurements at two nearshore locations in the Gulf of Finland, clear evidence of winter “warm” upwelling events was detected and analysed. The process was very common. At a 10 m deep location, upwelling caused water temperature (T) to switch from 0–1 to 4–5°C and salinity (S) to switch from 4.5 to 6 PSU; at 20 m depth it caused a switch in T between 1 and 2–4°C and in S between 5.5 and 6.8 PSU. Differently from summer upwelling, T and S variations were positively correlated to each other. Salinity variations remained roughly the same throughout the winter, whereas T differences were higher in winter onset, then decreased to ca. 1°C, and increased again after the process reversed to summer-type upwelling in April–May. Based on analysis of SatBaltyk (January to March) sea surface temperature and salinity product imagery, winter upwelling occurrence along the North Estonian coast was 21–28% over 2010–2021, and slightly less along the Finnish coast. Regarding S variations, winter upwelling occurred with roughly similar frequencies and impacts in the northern and southern parts of the gulf. However, the impacts on T and sea ice conditions were highly asymmetrical. Upwelling kept the Estonian coast ice-free longer and water temperatures slightly higher than at the Finnish coast. Winter upwelling as a phenomenon has long been ignored and therefore probably underestimated.http://www.sciencedirect.com/science/article/pii/S0078323421000361Warm upwellingStratificationVertical fluxWater temperatureSea ice |
| spellingShingle | Ülo Suursaar Winter upwelling in the Gulf of Finland, Baltic Sea Oceanologia Warm upwelling Stratification Vertical flux Water temperature Sea ice |
| title | Winter upwelling in the Gulf of Finland, Baltic Sea |
| title_full | Winter upwelling in the Gulf of Finland, Baltic Sea |
| title_fullStr | Winter upwelling in the Gulf of Finland, Baltic Sea |
| title_full_unstemmed | Winter upwelling in the Gulf of Finland, Baltic Sea |
| title_short | Winter upwelling in the Gulf of Finland, Baltic Sea |
| title_sort | winter upwelling in the gulf of finland baltic sea |
| topic | Warm upwelling Stratification Vertical flux Water temperature Sea ice |
| url | http://www.sciencedirect.com/science/article/pii/S0078323421000361 |
| work_keys_str_mv | AT ulosuursaar winterupwellinginthegulfoffinlandbalticsea |