Lagrangian circulation of Antarctic Intermediate Water in the subtropical South Atlantic
Richardson, Philip L.
Davis, Russ E.
MetadataShow full item record
KeywordAntarctic Intermediate Water (AAIW); Floats; Neutral density surfaces; South Atlantic; Lagrangian circulation; Transports; Objective analysis
This study combines float data from different projects collected between 1991 and 2003 in the South Atlantic to describe the flow of Antarctic Intermediate Water (AAIW). Velocity spacetime averages are calculated for various grid resolutions and with cells deformed to match the bathymetry, f/H or f/h (with H being the water depth and h being the thickness of the AAIW layer). When judged by the degree of alignment between respective isolines and the resulting average velocity fields, the best grid is based on a nominal cell size of 3º (latitude) by 4º (longitude) with cell shapes deformed according to f/h. Using this grid, objectively estimated mean currents (and their associated errors), as well as meridional and zonal volume transports are estimated. Results show an anticyclonic Subtropical Gyre centred near 36ºS and spanning from 23º±1°S to 46° ± 1ºS. The South Atlantic Current meanders from 33ºS to 46ºS and shows a mean speed of 9.6 ± 7.8 cm s-1 (8.5 Sv ± 3.5 Sv; 1 Sv = 1×106 m3 s-1). The northern branch of the Subtropical Gyre is located between 22ºS and 32ºS and flows westward with a mean speed of 4.7 ± 3.3 cm s-1 (9.3 Sv ± 3.4 Sv). Evidence of a cyclonic Tropical Gyre divided in two sub-cells is visible on the stream function.
Author Posting. © The Authors, 2004. This is the author's version of the work. It is posted here by permission of Elsevier B. V. for personal use, not for redistribution. The definitive version was published in Deep Sea Research Part II: Topical Studies in Oceanography 52 (2005): 545-564, doi:10.1016/j.dsr2.2004.12.006.
Showing items related by title, author, creator and subject.
Howe, Jacob N. W.; Piotrowski, Alexander M.; Oppo, Delia W.; Huang, Kuo-Fang; Mulitza, Stefan; Chiessi, Cristiano M.; Blusztajn, Jerzy S. (John Wiley & Sons, 2016-10-05)Antarctic Intermediate Water is an essential limb of the Atlantic meridional overturning circulation that redistributes heat and nutrients within the Atlantic Ocean. Existing reconstructions have yielded conflicting results ...
Decreased influence of Antarctic intermediate water in the tropical Atlantic during North Atlantic cold events Huang, Kuo-Fang; Oppo, Delia W.; Curry, William B. (Elsevier, 2014-01-15)Antarctic Intermediate Water (AAIW) is a key player in the global ocean circulation, contributing to the upper limb of the Atlantic Meridional Overturning Circulation (AMOC), and influencing interhemispheric heat exchange ...
Evidence of silicic acid leakage to the tropical Atlantic via Antarctic Intermediate Water during Marine Isotope Stage 4 Griffiths, James D.; Barker, Stephen; Hendry, Katharine R.; Thornalley, David J. R.; van de Flierdt, Tina; Hall, Ian R.; Anderson, Robert F. (John Wiley & Sons, 2013-06-27)Antarctic Intermediate Water (AAIW) and Subantarctic Mode Water (SAMW) are the main conduits for the supply of dissolved silicon (silicic acid) from the deep Southern Ocean (SO) to the low-latitude surface ocean and therefore ...