Open AccessTemporal evolution of the tracer signal in the Deep Western Boundary Current, tropical Atlantic
Author(s) -
Rhein Monika,
Plähn Olaf,
Bayer Reinhold,
Stramma Lothar,
Arnold Matthias
Publication year - 1998
Publication title -
journal of geophysical research: oceans
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/98jc00143
Subject(s) - tropical atlantic , north atlantic deep water , tracer , hydrography , oceanography , geology , thermohaline circulation , climatology , water mass , convective mixing , atlantic equatorial mode , ocean gyre , convection , subtropics , geography , sea surface temperature , meteorology , physics , fishery , nuclear physics , biology
Four World Ocean Circulation Experiment (WOCE) repeat cruises (October 1990 to March 1994) in the tropical Atlantic off Brazil are used to study the spatial and temporal evolution of the chlorofluorocarbon (CFC) (components CFC‐11 and CFC‐12) and tritium signal in the upper North Atlantic Deep Water (NADW). Its shallowest part, located in the tropical Atlantic around 1600‐m depth, is the shallow upper North Atlantic Deep Water (SUNADW). It is characterized by a distinct tracer maximum, which is presumably received through winter time convection in the subpolar North Atlantic. Here we discuss the tracer fields and the temporal evolution of the tracer signal of the SUNADW in the tropical Atlantic along two meridional sections at 44° and 35°W and two zonal sections at 5° and 10°S off Brazil. The spatial and temporal development of the tracer field in the tropical Atlantic as well as the correlation with hydrographic parameters show that the temporal tracer change being due to the arrival of “younger” water is disturbed by other processes. In particular, the impact of variable mixing and spreading pathways on the observed tracer variability in the SUNADW is evident in the observations.