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Abstract A high‐resolution ocean model is used to characterize the variability of the shelf circulation and cross‐shelf transport around the South Georgia island (SG). The time‐mean shelf circulation consists of a counterclockwise flow with a net onshelf mass flow in the south and a net offshelf mass flow in the north. In the south, the cross‐shelf exchanges show a two‐layer structure with an offshelf flow below 350 m and onshelf flow above. In the north, the cross‐shelf exchanges show a three‐layer structure with the onshelf flow found only between 350 and 50 m. Correlation analysis shows that winds and the Southern Antarctic Circumpolar Current Front (SACCF) current modulate the variability of the shelf circulation and cross‐shelf transport. Local wind stress is significantly correlated with the coastal currents, mid‐shelf jet, and cross‐shelf transports in the upper layer, while the SACCF modulates the shelf and cross‐shelf transports in the southwestern shelf. Likewise, an Empirical Orthogonal Function analysis indicates that the first mode of shelf circulation variability is highly correlated with the SACCF, while the second mode is explained by the local wind stress and significantly correlated with the Antarctic Oscillation. The El Niño Southern Oscillation does not significantly contribute to the shelf circulation but is significantly correlated with the surface temperature variability. The atmospheric teleconnection drives changes in local heat flux, such that warm El Niño conditions over the equatorial Pacific are associated with a cooling of the SG waters. This superposes local signals onto temperature anomalies advected from upstream in the ACC found in previous studies.
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The Late Quaternary Flow through the Bering Strait Has Been Forced by the Southern Ocean Winds
Abstract Because North and South America are surrounded by water, they constitute together a gigantic island whose peripheral sea level is controlled by the winds east of the island, winds along the western boundary of the island, the freshwater flux, and the meridional overturning cell. This idea has been expressed in several articles where a series of analytical models show that the Bering Strait (BS) flow is controlled by the interplay of the Southern Winds (sometimes referred to as the “Subantarctic Westerlies”), and the North Hemisphere freshwater flux. Here, the authors report a paleoceanographic analysis of proxies in the BS as well as the Southern Ocean, which clearly support the above through employment of a slowly varying time-dependent version of the coupled Sandal–Nof model. This study shows a very strong correlation between the Southern Ocean winds and the BS flow. A mid-Holocene weakening of the Southern Winds followed by the cession of freshwater fluxes from the melting Laurentide ice sheet strengthened the BS flow for several thousand years. Increasing the Southern Winds enhances the near surface, cross-equatorial flow from the Southern Ocean to the Northern Hemisphere. This cross-equatorial flow decreases the Arctic outflow into the Atlantic demonstrating a dynamic linkage between the Southern Ocean Winds and the mean flow through the BS.
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- PAR ID:
- 10530125
- Publisher / Repository:
- American Meteorological Society
- Date Published:
- Journal Name:
- Journal of Physical Oceanography
- Volume:
- 42
- Issue:
- 11
- ISSN:
- 0022-3670
- Page Range / eLocation ID:
- 2014 to 2029
- Subject(s) / Keyword(s):
- Bering Strait Antarctic Peninsula Westerly Winds Magnetic susceptibility
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1175/JPO-D-11-0167.1
