Ocean Circulation and Dynamics on the West Antarctic Peninsula Continental Shelf
Observations of current velocity, temperature, salinity and pressure from a 2-year moored array deployment and four hydrographic cruises conducted by the United States Southern Ocean GLOBEC program on the western Antarctic Peninsula continental shelf are used to characterize the ocean circulation an...
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ftdtic:ADA478738 2023-05-15T13:58:29+02:00 Ocean Circulation and Dynamics on the West Antarctic Peninsula Continental Shelf Varas, Carlos F. MASSACHUSETTS INST OF TECH CAMBRIDGE JOINT PROGRAM IN APPLIED OCEAN SCIENCE AND ENGINEERING 2007-09 text/html http://www.dtic.mil/docs/citations/ADA478738 http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA478738 en eng http://www.dtic.mil/docs/citations/ADA478738 Approved for public release; distribution is unlimited. DTIC Physical and Dynamic Oceanography Geography *OCEAN CURRENTS *SEASONAL VARIATIONS *BUOYANCY *ANTARCTIC REGIONS VELOCITY WIND BATHYMETRY GLACIERS SALINITY HEAT FLUX FRESH WATER TIDAL CURRENTS THESES TEMPERATURE *APCC(ANTARCTIC PENINSULA COASTAL CURRENT) KRILL Text 2007 ftdtic 2016-02-22T14:23:32Z Observations of current velocity, temperature, salinity and pressure from a 2-year moored array deployment and four hydrographic cruises conducted by the United States Southern Ocean GLOBEC program on the western Antarctic Peninsula continental shelf are used to characterize the ocean circulation and its connection to fresh water and heat fluxes on the shelf. Mean velocities on the shelf are of the order of 5 cm/s or less. Tidal motions are dominated by the M2 and S2 semi-diurnal tides and the O(1) and K(1) diurnal tides, although the tidal velocities are typically less than 2 cm/s. Near-inertial motions are relatively large, with current velocities as high as 26 cm/s. It is shown that Marguerite Trough, a large bathymetric feature connecting the shelf-break to Marguerite Bay, plays a critical role in determining the circulation. The mean flow is strongly steered in the along-slope direction, and the tidal currents also show increasing current polarization at depth in Marguerite Trough. At time-scales of 5 to 20 days, the observations show bottom-intensified motion in Marguerite Trough consistent with bottom-trapped topographic Rossby waves. The subtidal circulation in the trough has a significant wind-driven component in Marguerite Trough, with downwelling-favorable winds forcing cross-shelf flow on the northern side of the trough and along the shore on the outer shelf. Upwelling-favorable winds force roughly the opposite circulation. The cyclonic circulation on the trough helps advect blobs of salty, warm and nutrient-rich water across the shelf. These intrusions are small (approx. 4 km) and frequent (4 events/month). Also, the Antarctic Peninsula Coastal Current (APCC), a coastal buoyant current which is described for the first time here. The APCC is a seasonal current which is only present during the ice-free season and is forced by freshwater fluxes associated with large glacier melt and precipitation rates in the region. The original document contains color images. All DTIC reproductions will be in black and white. Text Antarc* Antarctic Antarctic Peninsula Southern Ocean Defense Technical Information Center: DTIC Technical Reports database Antarctic Southern Ocean 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) |
institution |
Open Polar |
collection |
Defense Technical Information Center: DTIC Technical Reports database |
op_collection_id |
ftdtic |
language |
English |
topic |
Physical and Dynamic Oceanography Geography *OCEAN CURRENTS *SEASONAL VARIATIONS *BUOYANCY *ANTARCTIC REGIONS VELOCITY WIND BATHYMETRY GLACIERS SALINITY HEAT FLUX FRESH WATER TIDAL CURRENTS THESES TEMPERATURE *APCC(ANTARCTIC PENINSULA COASTAL CURRENT) KRILL |
spellingShingle |
Physical and Dynamic Oceanography Geography *OCEAN CURRENTS *SEASONAL VARIATIONS *BUOYANCY *ANTARCTIC REGIONS VELOCITY WIND BATHYMETRY GLACIERS SALINITY HEAT FLUX FRESH WATER TIDAL CURRENTS THESES TEMPERATURE *APCC(ANTARCTIC PENINSULA COASTAL CURRENT) KRILL Varas, Carlos F. Ocean Circulation and Dynamics on the West Antarctic Peninsula Continental Shelf |
topic_facet |
Physical and Dynamic Oceanography Geography *OCEAN CURRENTS *SEASONAL VARIATIONS *BUOYANCY *ANTARCTIC REGIONS VELOCITY WIND BATHYMETRY GLACIERS SALINITY HEAT FLUX FRESH WATER TIDAL CURRENTS THESES TEMPERATURE *APCC(ANTARCTIC PENINSULA COASTAL CURRENT) KRILL |
description |
Observations of current velocity, temperature, salinity and pressure from a 2-year moored array deployment and four hydrographic cruises conducted by the United States Southern Ocean GLOBEC program on the western Antarctic Peninsula continental shelf are used to characterize the ocean circulation and its connection to fresh water and heat fluxes on the shelf. Mean velocities on the shelf are of the order of 5 cm/s or less. Tidal motions are dominated by the M2 and S2 semi-diurnal tides and the O(1) and K(1) diurnal tides, although the tidal velocities are typically less than 2 cm/s. Near-inertial motions are relatively large, with current velocities as high as 26 cm/s. It is shown that Marguerite Trough, a large bathymetric feature connecting the shelf-break to Marguerite Bay, plays a critical role in determining the circulation. The mean flow is strongly steered in the along-slope direction, and the tidal currents also show increasing current polarization at depth in Marguerite Trough. At time-scales of 5 to 20 days, the observations show bottom-intensified motion in Marguerite Trough consistent with bottom-trapped topographic Rossby waves. The subtidal circulation in the trough has a significant wind-driven component in Marguerite Trough, with downwelling-favorable winds forcing cross-shelf flow on the northern side of the trough and along the shore on the outer shelf. Upwelling-favorable winds force roughly the opposite circulation. The cyclonic circulation on the trough helps advect blobs of salty, warm and nutrient-rich water across the shelf. These intrusions are small (approx. 4 km) and frequent (4 events/month). Also, the Antarctic Peninsula Coastal Current (APCC), a coastal buoyant current which is described for the first time here. The APCC is a seasonal current which is only present during the ice-free season and is forced by freshwater fluxes associated with large glacier melt and precipitation rates in the region. The original document contains color images. All DTIC reproductions will be in black and white. |
author2 |
MASSACHUSETTS INST OF TECH CAMBRIDGE JOINT PROGRAM IN APPLIED OCEAN SCIENCE AND ENGINEERING |
format |
Text |
author |
Varas, Carlos F. |
author_facet |
Varas, Carlos F. |
author_sort |
Varas, Carlos F. |
title |
Ocean Circulation and Dynamics on the West Antarctic Peninsula Continental Shelf |
title_short |
Ocean Circulation and Dynamics on the West Antarctic Peninsula Continental Shelf |
title_full |
Ocean Circulation and Dynamics on the West Antarctic Peninsula Continental Shelf |
title_fullStr |
Ocean Circulation and Dynamics on the West Antarctic Peninsula Continental Shelf |
title_full_unstemmed |
Ocean Circulation and Dynamics on the West Antarctic Peninsula Continental Shelf |
title_sort |
ocean circulation and dynamics on the west antarctic peninsula continental shelf |
publishDate |
2007 |
url |
http://www.dtic.mil/docs/citations/ADA478738 http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA478738 |
long_lat |
ENVELOPE(141.378,141.378,-66.787,-66.787) ENVELOPE(-68.000,-68.000,-68.500,-68.500) |
geographic |
Antarctic Southern Ocean The Antarctic Antarctic Peninsula Marguerite Marguerite Bay |
geographic_facet |
Antarctic Southern Ocean The Antarctic Antarctic Peninsula Marguerite Marguerite Bay |
genre |
Antarc* Antarctic Antarctic Peninsula Southern Ocean |
genre_facet |
Antarc* Antarctic Antarctic Peninsula Southern Ocean |
op_source |
DTIC |
op_relation |
http://www.dtic.mil/docs/citations/ADA478738 |
op_rights |
Approved for public release; distribution is unlimited. |
_version_ |
1766266798050639872 |