On the detectability of internal tides in Drake Passage
The Southern Ocean hosts significant topographic mixing that might be associated with internal tides. Tidal signals are evident in bottom temperature at 1000 m in Drake Passage, suggesting that internal tides with an amplitude of between ∼20 and 200 m may be present. Various necessary conditions for...
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ftnerc:oai:nora.nerc.ac.uk:19338 2023-05-15T16:02:22+02:00 On the detectability of internal tides in Drake Passage Heywood, Karen J. Collins, Julie L. Hughes, Christopher W. Vassie, Ian 2007 http://nora.nerc.ac.uk/id/eprint/19338/ https://doi.org/10.1016/j.dsr.2007.08.002 unknown Heywood, Karen J.; Collins, Julie L.; Hughes, Christopher W. orcid:0000-0002-9355-0233 Vassie, Ian. 2007 On the detectability of internal tides in Drake Passage. Deep Sea Research Part I: Oceanographic Research Papers, 54 (11). 1972-1984. https://doi.org/10.1016/j.dsr.2007.08.002 <https://doi.org/10.1016/j.dsr.2007.08.002> Marine Sciences Publication - Article PeerReviewed 2007 ftnerc https://doi.org/10.1016/j.dsr.2007.08.002 2023-02-04T19:32:17Z The Southern Ocean hosts significant topographic mixing that might be associated with internal tides. Tidal signals are evident in bottom temperature at 1000 m in Drake Passage, suggesting that internal tides with an amplitude of between ∼20 and 200 m may be present. Various necessary conditions for internal tide generation show that the steep topography in and around Drake Passage can initiate internal tides, and recent global tide models have suggested this region to generate very large interface displacements. Here, we present an attempt to detect internal tides in Drake Passage. During the last 10 years, combinations of bottom pressure recorders and inverted echo sounders have been deployed in the region. The bottom pressure recorders measure predominantly the barotropic tide; the inverted echo sounders measure travel time from sea bed to sea surface and therefore are influenced both by sea level (barotropic tide) and internal sound speed (internal tide). By subtracting one from the other, the internal tide should be detectable. Although the technique works successfully around Hawaii, it does not prove the existence of large internal tides in Drake Passage. The detectability of the internal tidal signal in Drake Passage is investigated using a six-layer one-dimensional model to simulate the bottom pressure and travel time signals of a semi-diurnal tide. The temperature and salinity stratification in Drake Passage is sufficiently weak that large vertical excursions are necessary to produce a signal in travel time detectable above the noise in Drake Passage. An internal tide of at least 70 or 20 m in northern and southern Drake Passage, respectively, would be detected. The fact that these are, perhaps surprisingly, not detected by the combination of bottom pressure and travel time, constrains the internal tides in Drake Passage to be ∼20 m in southern Drake Passage, and between 20 and 70 m in northern Drake Passage. The model also predicts that satellite altimetry would not be able to detect internal tides in ... Article in Journal/Newspaper Drake Passage Southern Ocean Natural Environment Research Council: NERC Open Research Archive Southern Ocean Drake Passage Deep Sea Research Part I: Oceanographic Research Papers 54 11 1972 1984 |
institution |
Open Polar |
collection |
Natural Environment Research Council: NERC Open Research Archive |
op_collection_id |
ftnerc |
language |
unknown |
topic |
Marine Sciences |
spellingShingle |
Marine Sciences Heywood, Karen J. Collins, Julie L. Hughes, Christopher W. Vassie, Ian On the detectability of internal tides in Drake Passage |
topic_facet |
Marine Sciences |
description |
The Southern Ocean hosts significant topographic mixing that might be associated with internal tides. Tidal signals are evident in bottom temperature at 1000 m in Drake Passage, suggesting that internal tides with an amplitude of between ∼20 and 200 m may be present. Various necessary conditions for internal tide generation show that the steep topography in and around Drake Passage can initiate internal tides, and recent global tide models have suggested this region to generate very large interface displacements. Here, we present an attempt to detect internal tides in Drake Passage. During the last 10 years, combinations of bottom pressure recorders and inverted echo sounders have been deployed in the region. The bottom pressure recorders measure predominantly the barotropic tide; the inverted echo sounders measure travel time from sea bed to sea surface and therefore are influenced both by sea level (barotropic tide) and internal sound speed (internal tide). By subtracting one from the other, the internal tide should be detectable. Although the technique works successfully around Hawaii, it does not prove the existence of large internal tides in Drake Passage. The detectability of the internal tidal signal in Drake Passage is investigated using a six-layer one-dimensional model to simulate the bottom pressure and travel time signals of a semi-diurnal tide. The temperature and salinity stratification in Drake Passage is sufficiently weak that large vertical excursions are necessary to produce a signal in travel time detectable above the noise in Drake Passage. An internal tide of at least 70 or 20 m in northern and southern Drake Passage, respectively, would be detected. The fact that these are, perhaps surprisingly, not detected by the combination of bottom pressure and travel time, constrains the internal tides in Drake Passage to be ∼20 m in southern Drake Passage, and between 20 and 70 m in northern Drake Passage. The model also predicts that satellite altimetry would not be able to detect internal tides in ... |
format |
Article in Journal/Newspaper |
author |
Heywood, Karen J. Collins, Julie L. Hughes, Christopher W. Vassie, Ian |
author_facet |
Heywood, Karen J. Collins, Julie L. Hughes, Christopher W. Vassie, Ian |
author_sort |
Heywood, Karen J. |
title |
On the detectability of internal tides in Drake Passage |
title_short |
On the detectability of internal tides in Drake Passage |
title_full |
On the detectability of internal tides in Drake Passage |
title_fullStr |
On the detectability of internal tides in Drake Passage |
title_full_unstemmed |
On the detectability of internal tides in Drake Passage |
title_sort |
on the detectability of internal tides in drake passage |
publishDate |
2007 |
url |
http://nora.nerc.ac.uk/id/eprint/19338/ https://doi.org/10.1016/j.dsr.2007.08.002 |
geographic |
Southern Ocean Drake Passage |
geographic_facet |
Southern Ocean Drake Passage |
genre |
Drake Passage Southern Ocean |
genre_facet |
Drake Passage Southern Ocean |
op_relation |
Heywood, Karen J.; Collins, Julie L.; Hughes, Christopher W. orcid:0000-0002-9355-0233 Vassie, Ian. 2007 On the detectability of internal tides in Drake Passage. Deep Sea Research Part I: Oceanographic Research Papers, 54 (11). 1972-1984. https://doi.org/10.1016/j.dsr.2007.08.002 <https://doi.org/10.1016/j.dsr.2007.08.002> |
op_doi |
https://doi.org/10.1016/j.dsr.2007.08.002 |
container_title |
Deep Sea Research Part I: Oceanographic Research Papers |
container_volume |
54 |
container_issue |
11 |
container_start_page |
1972 |
op_container_end_page |
1984 |
_version_ |
1766397940399603712 |