Two-Hour Sea Level Oscillations in Halifax Harbour
Halifax Harbour, a major seaport in Nova Scotia that is approximately 100 km southeast of the Bay of Fundy, comprises a deep inner region called Bedford Basin, connected to the adjacent ocean by a shallow channel called The Narrows. A study of sea level and currents reveals the presence of episodic...
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2025-07-01
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| Series: | Journal of Marine Science and Engineering |
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| author | Dan Kelley Clark Richards Ruby Yee Alex Hay Knut Klingbeil Phillip MacAulay Ruth Musgrave |
| author_facet | Dan Kelley Clark Richards Ruby Yee Alex Hay Knut Klingbeil Phillip MacAulay Ruth Musgrave |
| author_sort | Dan Kelley |
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| description | Halifax Harbour, a major seaport in Nova Scotia that is approximately 100 km southeast of the Bay of Fundy, comprises a deep inner region called Bedford Basin, connected to the adjacent ocean by a shallow channel called The Narrows. A study of sea level and currents reveals the presence of episodic oscillations in The Narrows, with a period of approximately 2 h. The oscillation strength varies from day to day and, to some extent, through the seasons. The median amplitude of the associated sea level variation is <inline-formula><math display="inline"><semantics><mrow><mn>18</mn><mo>%</mo></mrow></semantics></math></inline-formula> that of the de-tided signal, rising to <inline-formula><math display="inline"><semantics><mrow><mn>32</mn><mo>%</mo></mrow></semantics></math></inline-formula> at the 95-th percentile. Values this large may be of concern for the transit of deep-draft vessels through shallow parts of the harbour and for the clearance of tall vessels under the two bridges that span The Narrows. Another concerning issue is the matter of oscillations being superimposed on storm surges. In addition to such direct effects of sea level variation, shear associated with the oscillations may increase the turbulent mixing in the region, affecting the overall state of this estuarine system. We explore the nature of the oscillations as a first step towards the improvement of prediction schemes for sea level and currents in the region. This involves an analysis of the oscillations in the context of seiche and Helmholtz resonance theories and the use of a 2D numerical model to handle realistic bathymetric conditions and other complications that the simpler theories cannot address. We conclude that the predictions of Helmholtz resonance theory are in reasonable agreement with both the observations and the predictions of the numerical model. |
| format | Article |
| id | doaj-art-29633e1b4e2145c7a91c5955be61d1d9 |
| institution | Kabale University |
| issn | 2077-1312 |
| language | English |
| publishDate | 2025-07-01 |
| publisher | MDPI AG |
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| series | Journal of Marine Science and Engineering |
| spelling | doaj-art-29633e1b4e2145c7a91c5955be61d1d92025-08-20T03:36:11ZengMDPI AGJournal of Marine Science and Engineering2077-13122025-07-01137136610.3390/jmse13071366Two-Hour Sea Level Oscillations in Halifax HarbourDan Kelley0Clark Richards1Ruby Yee2Alex Hay3Knut Klingbeil4Phillip MacAulay5Ruth Musgrave6Department of Oceanography, Dalhousie University, Halifax, NS B3H 4R2, CanadaBedford Institute of Oceanography, Department of Fisheries and Oceans Canada, Bedford, NS B2Y 4A2, CanadaDepartment of Oceanography, Dalhousie University, Halifax, NS B3H 4R2, CanadaDepartment of Oceanography, Dalhousie University, Halifax, NS B3H 4R2, CanadaLeibniz-Institute for Baltic Sea Research Warnemuende (IOW), Seestrasse 15, D-18119 Rostock, GermanyCanadian Hydrographic Service, Department of Fisheries and Oceans Canada, Bedford, NS B2Y 4A2, CanadaDepartment of Oceanography, Dalhousie University, Halifax, NS B3H 4R2, CanadaHalifax Harbour, a major seaport in Nova Scotia that is approximately 100 km southeast of the Bay of Fundy, comprises a deep inner region called Bedford Basin, connected to the adjacent ocean by a shallow channel called The Narrows. A study of sea level and currents reveals the presence of episodic oscillations in The Narrows, with a period of approximately 2 h. The oscillation strength varies from day to day and, to some extent, through the seasons. The median amplitude of the associated sea level variation is <inline-formula><math display="inline"><semantics><mrow><mn>18</mn><mo>%</mo></mrow></semantics></math></inline-formula> that of the de-tided signal, rising to <inline-formula><math display="inline"><semantics><mrow><mn>32</mn><mo>%</mo></mrow></semantics></math></inline-formula> at the 95-th percentile. Values this large may be of concern for the transit of deep-draft vessels through shallow parts of the harbour and for the clearance of tall vessels under the two bridges that span The Narrows. Another concerning issue is the matter of oscillations being superimposed on storm surges. In addition to such direct effects of sea level variation, shear associated with the oscillations may increase the turbulent mixing in the region, affecting the overall state of this estuarine system. We explore the nature of the oscillations as a first step towards the improvement of prediction schemes for sea level and currents in the region. This involves an analysis of the oscillations in the context of seiche and Helmholtz resonance theories and the use of a 2D numerical model to handle realistic bathymetric conditions and other complications that the simpler theories cannot address. We conclude that the predictions of Helmholtz resonance theory are in reasonable agreement with both the observations and the predictions of the numerical model.https://www.mdpi.com/2077-1312/13/7/1366harboursea leveloscillationHelmholtz resonance |
| spellingShingle | Dan Kelley Clark Richards Ruby Yee Alex Hay Knut Klingbeil Phillip MacAulay Ruth Musgrave Two-Hour Sea Level Oscillations in Halifax Harbour Journal of Marine Science and Engineering harbour sea level oscillation Helmholtz resonance |
| title | Two-Hour Sea Level Oscillations in Halifax Harbour |
| title_full | Two-Hour Sea Level Oscillations in Halifax Harbour |
| title_fullStr | Two-Hour Sea Level Oscillations in Halifax Harbour |
| title_full_unstemmed | Two-Hour Sea Level Oscillations in Halifax Harbour |
| title_short | Two-Hour Sea Level Oscillations in Halifax Harbour |
| title_sort | two hour sea level oscillations in halifax harbour |
| topic | harbour sea level oscillation Helmholtz resonance |
| url | https://www.mdpi.com/2077-1312/13/7/1366 |
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