Modification of deep waters in Marguerite Bay, western Antarctic Peninsula, caused by topographic overflows
Circumpolar Deep Water (CDW) intrudes from the mid-layers of the Antarctic Circumpolar Current onto the shelf of the western Antarctic Peninsula, providing a source of heat and nutrients to the regional ocean. It is well known that CDW is modified as it flows across the shelf, but the mechanisms res...
Published in: | Deep Sea Research Part II: Topical Studies in Oceanography |
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ftnerc:oai:nora.nerc.ac.uk:513104 2023-05-15T13:49:32+02:00 Modification of deep waters in Marguerite Bay, western Antarctic Peninsula, caused by topographic overflows Venables, Hugh J. Meredith, Michael P. Brearley, J. Alexander 2017-05 text http://nora.nerc.ac.uk/id/eprint/513104/ https://nora.nerc.ac.uk/id/eprint/513104/1/Modification%20of%20deep%20waters%20in%20Marguerite%20Bay,%20western%20Antarctic%20Peninsula%20AAM.pdf http://www.sciencedirect.com/science/article/pii/S0967064516302843 en eng Elsevier https://nora.nerc.ac.uk/id/eprint/513104/1/Modification%20of%20deep%20waters%20in%20Marguerite%20Bay,%20western%20Antarctic%20Peninsula%20AAM.pdf Venables, Hugh J.; Meredith, Michael P. orcid:0000-0002-7342-7756 Brearley, J. Alexander orcid:0000-0003-3700-8017 . 2017 Modification of deep waters in Marguerite Bay, western Antarctic Peninsula, caused by topographic overflows. Deep Sea Research II: Topical Studies in Oceanography, 139. 9-17. https://doi.org/10.1016/j.dsr2.2016.09.005 <https://doi.org/10.1016/j.dsr2.2016.09.005> Publication - Article PeerReviewed 2017 ftnerc https://doi.org/10.1016/j.dsr2.2016.09.005 2023-02-04T19:42:47Z Circumpolar Deep Water (CDW) intrudes from the mid-layers of the Antarctic Circumpolar Current onto the shelf of the western Antarctic Peninsula, providing a source of heat and nutrients to the regional ocean. It is well known that CDW is modified as it flows across the shelf, but the mechanisms responsible for this are not fully known. Here, data from underwater gliders with high spatial resolution are used to demonstrate the importance of detailed bathymetry in inducing multiple local mixing events. Clear evidence for overflows is observed in the glider data as water flows along a deep channel with multiple transverse ridges. The ridges block the densest waters, with overflowing water descending several hundred metres to fill subsequent basins. This vertical flow leads to entrainment of overlying colder and fresher water in localised mixing events. Initially this process leads to an increase in bottom temperatures due to the temperature maximum waters descending to greater depths. After several ridges, however, the mixing is sufficient to remove the temperature maximum completely and the entrainment of colder thermocline waters to depth reduces the bottom temperature, to approximately the same as in the source region of Marguerite Trough. Similarly, it is shown that deep waters of Palmer Deep are warmer than at the same depth at the shelf break. The exact details of the transformations observed are heavily dependent on the local bathymetry and water column structure, but glacially-carved troughs and shallow sills are a common feature of the bathymetry of polar shelves, and these types of processes may be a factor in determining the hydrographic conditions close to the coast across a wider area. Article in Journal/Newspaper Antarc* Antarctic Antarctic Peninsula Natural Environment Research Council: NERC Open Research Archive Antarctic The Antarctic Antarctic Peninsula Marguerite ENVELOPE(141.378,141.378,-66.787,-66.787) Marguerite Bay ENVELOPE(-68.000,-68.000,-68.500,-68.500) Palmer Deep ENVELOPE(-64.400,-64.400,-64.950,-64.950) Deep Sea Research Part II: Topical Studies in Oceanography 139 9 17 |
institution |
Open Polar |
collection |
Natural Environment Research Council: NERC Open Research Archive |
op_collection_id |
ftnerc |
language |
English |
description |
Circumpolar Deep Water (CDW) intrudes from the mid-layers of the Antarctic Circumpolar Current onto the shelf of the western Antarctic Peninsula, providing a source of heat and nutrients to the regional ocean. It is well known that CDW is modified as it flows across the shelf, but the mechanisms responsible for this are not fully known. Here, data from underwater gliders with high spatial resolution are used to demonstrate the importance of detailed bathymetry in inducing multiple local mixing events. Clear evidence for overflows is observed in the glider data as water flows along a deep channel with multiple transverse ridges. The ridges block the densest waters, with overflowing water descending several hundred metres to fill subsequent basins. This vertical flow leads to entrainment of overlying colder and fresher water in localised mixing events. Initially this process leads to an increase in bottom temperatures due to the temperature maximum waters descending to greater depths. After several ridges, however, the mixing is sufficient to remove the temperature maximum completely and the entrainment of colder thermocline waters to depth reduces the bottom temperature, to approximately the same as in the source region of Marguerite Trough. Similarly, it is shown that deep waters of Palmer Deep are warmer than at the same depth at the shelf break. The exact details of the transformations observed are heavily dependent on the local bathymetry and water column structure, but glacially-carved troughs and shallow sills are a common feature of the bathymetry of polar shelves, and these types of processes may be a factor in determining the hydrographic conditions close to the coast across a wider area. |
format |
Article in Journal/Newspaper |
author |
Venables, Hugh J. Meredith, Michael P. Brearley, J. Alexander |
spellingShingle |
Venables, Hugh J. Meredith, Michael P. Brearley, J. Alexander Modification of deep waters in Marguerite Bay, western Antarctic Peninsula, caused by topographic overflows |
author_facet |
Venables, Hugh J. Meredith, Michael P. Brearley, J. Alexander |
author_sort |
Venables, Hugh J. |
title |
Modification of deep waters in Marguerite Bay, western Antarctic Peninsula, caused by topographic overflows |
title_short |
Modification of deep waters in Marguerite Bay, western Antarctic Peninsula, caused by topographic overflows |
title_full |
Modification of deep waters in Marguerite Bay, western Antarctic Peninsula, caused by topographic overflows |
title_fullStr |
Modification of deep waters in Marguerite Bay, western Antarctic Peninsula, caused by topographic overflows |
title_full_unstemmed |
Modification of deep waters in Marguerite Bay, western Antarctic Peninsula, caused by topographic overflows |
title_sort |
modification of deep waters in marguerite bay, western antarctic peninsula, caused by topographic overflows |
publisher |
Elsevier |
publishDate |
2017 |
url |
http://nora.nerc.ac.uk/id/eprint/513104/ https://nora.nerc.ac.uk/id/eprint/513104/1/Modification%20of%20deep%20waters%20in%20Marguerite%20Bay,%20western%20Antarctic%20Peninsula%20AAM.pdf http://www.sciencedirect.com/science/article/pii/S0967064516302843 |
long_lat |
ENVELOPE(141.378,141.378,-66.787,-66.787) ENVELOPE(-68.000,-68.000,-68.500,-68.500) ENVELOPE(-64.400,-64.400,-64.950,-64.950) |
geographic |
Antarctic The Antarctic Antarctic Peninsula Marguerite Marguerite Bay Palmer Deep |
geographic_facet |
Antarctic The Antarctic Antarctic Peninsula Marguerite Marguerite Bay Palmer Deep |
genre |
Antarc* Antarctic Antarctic Peninsula |
genre_facet |
Antarc* Antarctic Antarctic Peninsula |
op_relation |
https://nora.nerc.ac.uk/id/eprint/513104/1/Modification%20of%20deep%20waters%20in%20Marguerite%20Bay,%20western%20Antarctic%20Peninsula%20AAM.pdf Venables, Hugh J.; Meredith, Michael P. orcid:0000-0002-7342-7756 Brearley, J. Alexander orcid:0000-0003-3700-8017 . 2017 Modification of deep waters in Marguerite Bay, western Antarctic Peninsula, caused by topographic overflows. Deep Sea Research II: Topical Studies in Oceanography, 139. 9-17. https://doi.org/10.1016/j.dsr2.2016.09.005 <https://doi.org/10.1016/j.dsr2.2016.09.005> |
op_doi |
https://doi.org/10.1016/j.dsr2.2016.09.005 |
container_title |
Deep Sea Research Part II: Topical Studies in Oceanography |
container_volume |
139 |
container_start_page |
9 |
op_container_end_page |
17 |
_version_ |
1766251524598530048 |