Publication Date:
2022-05-25
Description:
Author Posting. © The Author(s), 2009. 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 I: Oceanographic Research Papers 56 (2009): 1615-1632, doi:10.1016/j.dsr.2009.06.002.
Description:
A comprehensive analysis of velocity data from subsurface floats in the northwestern tropical
Atlantic at two depth layers is presented: one representing the Antarctic Intermediate
Water (AAIW, pressure range 600–1050 dbar), the other the upper North Atlantic Deep
Water (uNADW, pressure range 1200–2050 dbar). New data from three independent research programs are combined with previously available data to achieve blanket coverage
in space for the AAIW layer, while coverage in the uNADW remains more intermittent.
Results from the AAIW mainly confirm previous studies on the mean flow, namely the
equatorial zonal and the boundary currents, but clarify details on pathways, mostly by
virtue of the spatial data coverage that sets float observations apart from e. g. shipborne
or mooring observations. Mean transports in each of five zonal equatorial current bands
is found to be between 2.7 and 4.5 Sv. Pathways carrying AAIW northward beyond the
North Brazil Undercurrent are clearly visible in the mean velocity field, in particular a
northward transport of 3.7 Sv across 16° N between the Antilles islands and the Mid-
Atlantic Ridge. New maps of Lagrangian eddy kinetic energy and integral time scales
are presented to quantify mesoscale activity. For the uNADW, mean flow and mesoscale
properties are discussed as data availability allows. Trajectories in the uNADWeast of the
Lesser Antilles reveal interactions between the Deep Western Boundary Current (DWBC)
and the basin interior, which can explain recent hydrographic observations of changes in
composition of DWBC water along its southward flow.
Description:
MOVE was funded by the Bundesministerium fu¨r Bildung und Forschung (grants
03F0246A and 03F0377B) as well as by the Deutsche Forschungsgemeinschaft (grant
SE815/21), NBC by the National Science Foundation through grants OCE 97-29765 and
OCE 01-36477, and SAMBA was fully supported by Ifremer.
Keywords:
Floats
;
Tropical Atlantic
;
Antarctic Intermediate Water
;
North Atlantic Deep Wat
;
Equatorial currents
Repository Name:
Woods Hole Open Access Server
Type:
Preprint
Format:
application/pdf
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