Status: this preprint was under review for the journal OS but the revision was not accepted.
Water masses and zonal current in the Western Tropical Atlantic in October 2007 and January 2008 (AMANDES project)
A. C. Silva,M. Grenier,R. Chuchla,J. Grelet,F. Roubaud,B. Hamelin,F. Lyard,and C. Jeandel
Abstract. The properties and circulation of water masses are examined using data collected from a hydrographic and Acoustic Doppler Current profiler in the Western Tropical Atlantic during two cruises of the GEOTRACES process study "AMANDES" (AMazon-ANDEans): AMANDES I (October–November 2007) and AMANDES II (January 2008). In the upper layer (from the sea surface to 150 m) means of vertical sections of velocity are showing the structure of the Current (NBC) and North Equatorial Countercurrent. In the lower layer (below 150 m) the subsurface velocity core of the North Brazil UnderCurrent, Western Boundary Undercurrent (WBUC) and northern branch of the South Equatorial Current (nSEC) could be observed. In October the WBUC flows southeastward with a velocity of about 0.3 m s−1. In the studied area during October 2007, the NBUC and nSEC are transporting South Atlantic Central Water (SACW) from the Southern Hemisphere whereas the WBUC transports North Atlantic Central Water (NACW) southeastward. In the deep layers, the North Atlantic Deep Water (NADW) is composed of three components: the Upper North Atlantic Deep Water – UNADW (between 1310 and 1650 m), the Middle North Atlantic Deep Water (between 1930 and 2400 m), the Lower North Atlantic Deep Water (centered around 3430 m).
Off Guyana, the Antartic Intermediate Water (AAIW) changes of composition between October 2007 (45.2% ACW, 32.2% AAIWsource and 22.6% UNADW) and January 2008 (62.4% ACW, 23.5% AAIWsource and 14.1% UNADW).
These intermediate waters are significantly warmer, less oxygenated and saltier than their southern source, reflecting both oxygen consumption and mixing with the Atlantic Central Water (ACW) and the Upper North Atlantic Deep Water during their northward transit.
Received: 16 Oct 2010 – Discussion started: 30 Nov 2010
Publisher's note: Copernicus Publications remains neutral with regard to jurisdictional claims made in the text, published maps, institutional affiliations, or any other geographical representation in this preprint. The responsibility to include appropriate place names lies with the authors.
A. C. Silva,M. Grenier,R. Chuchla,J. Grelet,F. Roubaud,B. Hamelin,F. Lyard,and C. Jeandel
A. C. Silva,M. Grenier,R. Chuchla,J. Grelet,F. Roubaud,B. Hamelin,F. Lyard,and C. Jeandel
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A. C. Silva
Laboratório de Oceanografia Física, Departamento de Oceanografia da Universidade Federal de Pernambuco, Av. Arquitetura s/n, 50740-550, Campus Universitário, Recife, PE, Brazil
M. Grenier
Laboratoire d'Etudes en Géophysique et Océanographie Spatiale (LEGOS), UPS/CNES/CNRS/IRD, Observatoire Midi-Pyrénées, 14 av. E. Belin, 31400 Toulouse, France
R. Chuchla
Laboratoire d'Etudes en Géophysique et Océanographie Spatiale (LEGOS), UPS/CNES/CNRS/IRD, Observatoire Midi-Pyrénées, 14 av. E. Belin, 31400 Toulouse, France
J. Grelet
US IMAGO, IRD Brest, 29240 Plouzané, France
F. Roubaud
US IMAGO, IRD Brest, 29240 Plouzané, France
B. Hamelin
CEREGE (CNRS/Univ Paul Cezane) Technopôle de l'Arbois, Aix en Provence, France
F. Lyard
Laboratoire d'Etudes en Géophysique et Océanographie Spatiale (LEGOS), UPS/CNES/CNRS/IRD, Observatoire Midi-Pyrénées, 14 av. E. Belin, 31400 Toulouse, France
C. Jeandel
Laboratoire d'Etudes en Géophysique et Océanographie Spatiale (LEGOS), UPS/CNES/CNRS/IRD, Observatoire Midi-Pyrénées, 14 av. E. Belin, 31400 Toulouse, France