Low-frequency thermohaline variability in the Subtropical South Atlantic pycnocline during 2002-2013

Type Article
Date 2014-09
Language English
Author(s) Kolodziejczyk NicolasORCID1, Reverdin Gilles1, Gaillard FabienneORCID2, Lazar Alban1
Affiliation(s) 1 : Univ Paris 06, CNRS, Univ Paris 04, IRD,MNHN,LOCEAN Lab, Paris, France.
2 : IFREMER, Lab Phys Oceans, UMR 6523, CNRS,IRD,UBO, Plouzane, France.
Source Geophysical Research Letters (0094-8276) (Amer Geophysical Union), 2014-09 , Vol. 41 , N. 18 , P. 6468-6475
DOI 10.1002/2014GL061160
WOS© Times Cited 8
Abstract Low-frequency variability of spiciness is observed in the Subtropical South Atlantic over the period 2002–2013 with the Argo gridded product In Situ Analysis System. Within the pycnocline, spiciness anomalies propagate at a mean speed of 0.04 ± 0.02 m s−1, the same speed as the gyre mean circulation, from the Agulhas Retroflection region off South Africa (~35°S–20°E) toward the South American coast (~18°S–35°W). After 2010, propagation is still found, but stationary local spiciness generation is also found over the Subtropical South Atlantic. This spiciness increase is associated with high values of vertical Turner angle below the mixed layer base during late winter. This suggests spice injection resulting from penetrative convective mixing due to air-sea buoyancy loss. These features may have an impact on the low-frequency warm and salty signal produced by the Agulhas leakage in Subtropical South Atlantic and the upper branch of the Atlantic Meridional Overturning Circulation.
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