Lagrangian circulation of Antarctic Intermediate Water in the subtropical South Atlantic

Type Article
Date 2005-02
Language English
Author(s) Nunez Riboni Ismael, Boebel Olaf, Ollitrault Michel, You Yuzhu, Richardson Philip, Davis Russ
Affiliation(s) Alfred Wegener Inst Polar & Marine Res, D-27570 Bremerhaven, Germany.
IFREMER, Ctr Brest, F-29280 Plouzane, France.
Univ Sydney, Inst Marine Sci, Sydney, NSW 2006, Australia.
Woods Hole Oceanog Inst, Woods Hole, MA 02543 USA.
Univ Calif San Diego, Scripps Inst Oceanog, La Jolla, CA 92093 USA.
Source Deep Sea Research Part II: Topical Studies in Oceanography (0967-0645) (Elsevier), 2005-02 , Vol. 52 , N. 3-4 , P. 545-564
DOI 10.1016/j.dsr2.2004.12.006
WOS© Times Cited 16
Keyword(s) Objective analysis, Transports, Lagrangian circulation, South Atlantic, Neutral density surfaces, Floats, Antarctic Intermediate Water ( AAIW )
Abstract 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 space-time 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 It 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 3° (latitude) by 4° (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 36° S and spanning from 23 ± 1° S to 46 + 1° S. The South Atlantic Current meanders from 33° S to 46° S and shows a mean speed of 9.6 ± 7.8 cm s(-1) (8.5 ± 3.5 Sv; 1 Sv = 1 x 10(6) m(3) s(-1)). The northern branch of the Subtropical Gyre is located between 22° s and 32° S and flows westward with a mean speed of 4.7 ± 3.3 cm s(-1) (9.3 ± 3.4 Sv). Evidence of a cyclonic Tropical Gyre divided in two sub-cells is visible on the stream function. © 2005 Elsevier Ltd. All rights reserved.
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Nunez Riboni Ismael, Boebel Olaf, Ollitrault Michel, You Yuzhu, Richardson Philip, Davis Russ (2005). Lagrangian circulation of Antarctic Intermediate Water in the subtropical South Atlantic. Deep Sea Research Part II: Topical Studies in Oceanography, 52(3-4), 545-564. Publisher's official version : https://doi.org/10.1016/j.dsr2.2004.12.006 , Open Access version : https://archimer.ifremer.fr/doc/00000/781/