Intermediate water in the Brazil-Malvinas Confluence Zone

A Lagrangian view

Olaf Boebel, Claudia Schmid, Guillermo P Podesta, Walter Zenk

Research output: Contribution to journalArticle

17 Citations (Scopus)

Abstract

The subsurface flow within the subantarctic and subtropical regions around the Brazil-Malvinas (Falkland) Confluence Zone is studied, using daily hydrographic and kinematic data from four subsurface floats and a hydrographic section parallel to the South American shelf. The float trajectories are mapped against sea surface flow patterns as visible in concurrent satellite sea surface temperature (SST) images, with focus on the November 1994 and October/November 1995 periods. The unprecedented employment of Lagrangian θ-5 diagrams enables us to trace the advection of patches of fresh Antarctic Intermediate Water (AAIW) from the Confluence Zone into the subtropical region. The fresh AAIW consists of a mixture of subtropical AAIW and Malvinas Current core water. Within the subtropical gyre, these patches are discernible for extended periods and drift over long distances, reaching north to 34° S and east to 40° W. The cross-frontal migration of quasi-isobaric floats across the Confluence Zone from the subtropical to the subantarctic environment is observed on three occasions. The reverse process, float migration from a subpolar to a subtropical environment was observed once. These events were located near 40° S, 50° W, the site of a reoccurring cold core feature. Subsurface float and SST data comparison reveals similarities with analogous observations made in the Gulf Stream [Rossby, 1996] where cross-frontal processes were observed close to meander crests. The limited number of floats of this study and the complex structure of the Brazil-Malvinas Confluence Zone, however, restricts the analysis to a description of two events.

Original languageEnglish (US)
Article number1999JC900059
Pages (from-to)21063-21082
Number of pages20
JournalJournal of Geophysical Research C: Oceans
Volume104
Issue numberC9
StatePublished - Sep 15 1999

Fingerprint

floats
intermediate water
Brazil
confluence
Antarctic Intermediate Water
Water
subtropical region
subtropical regions
water
sea surface temperature
subantarctic region
Advection
meander
subsurface flow
gyre
Gulf Stream
flow pattern
Flow patterns
sea surface
advection

ASJC Scopus subject areas

  • Geochemistry and Petrology
  • Geophysics
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science
  • Atmospheric Science
  • Astronomy and Astrophysics
  • Oceanography

Cite this

Intermediate water in the Brazil-Malvinas Confluence Zone : A Lagrangian view. / Boebel, Olaf; Schmid, Claudia; Podesta, Guillermo P; Zenk, Walter.

In: Journal of Geophysical Research C: Oceans, Vol. 104, No. C9, 1999JC900059, 15.09.1999, p. 21063-21082.

Research output: Contribution to journalArticle

Boebel, O, Schmid, C, Podesta, GP & Zenk, W 1999, 'Intermediate water in the Brazil-Malvinas Confluence Zone: A Lagrangian view', Journal of Geophysical Research C: Oceans, vol. 104, no. C9, 1999JC900059, pp. 21063-21082.
Boebel, Olaf ; Schmid, Claudia ; Podesta, Guillermo P ; Zenk, Walter. / Intermediate water in the Brazil-Malvinas Confluence Zone : A Lagrangian view. In: Journal of Geophysical Research C: Oceans. 1999 ; Vol. 104, No. C9. pp. 21063-21082.
@article{0532ef7a398e4af2a5a6c72459410bfa,
title = "Intermediate water in the Brazil-Malvinas Confluence Zone: A Lagrangian view",
abstract = "The subsurface flow within the subantarctic and subtropical regions around the Brazil-Malvinas (Falkland) Confluence Zone is studied, using daily hydrographic and kinematic data from four subsurface floats and a hydrographic section parallel to the South American shelf. The float trajectories are mapped against sea surface flow patterns as visible in concurrent satellite sea surface temperature (SST) images, with focus on the November 1994 and October/November 1995 periods. The unprecedented employment of Lagrangian θ-5 diagrams enables us to trace the advection of patches of fresh Antarctic Intermediate Water (AAIW) from the Confluence Zone into the subtropical region. The fresh AAIW consists of a mixture of subtropical AAIW and Malvinas Current core water. Within the subtropical gyre, these patches are discernible for extended periods and drift over long distances, reaching north to 34° S and east to 40° W. The cross-frontal migration of quasi-isobaric floats across the Confluence Zone from the subtropical to the subantarctic environment is observed on three occasions. The reverse process, float migration from a subpolar to a subtropical environment was observed once. These events were located near 40° S, 50° W, the site of a reoccurring cold core feature. Subsurface float and SST data comparison reveals similarities with analogous observations made in the Gulf Stream [Rossby, 1996] where cross-frontal processes were observed close to meander crests. The limited number of floats of this study and the complex structure of the Brazil-Malvinas Confluence Zone, however, restricts the analysis to a description of two events.",
author = "Olaf Boebel and Claudia Schmid and Podesta, {Guillermo P} and Walter Zenk",
year = "1999",
month = "9",
day = "15",
language = "English (US)",
volume = "104",
pages = "21063--21082",
journal = "Journal of Geophysical Research: Oceans",
issn = "2169-9275",
publisher = "Wiley-Blackwell",
number = "C9",

}

TY - JOUR

T1 - Intermediate water in the Brazil-Malvinas Confluence Zone

T2 - A Lagrangian view

AU - Boebel, Olaf

AU - Schmid, Claudia

AU - Podesta, Guillermo P

AU - Zenk, Walter

PY - 1999/9/15

Y1 - 1999/9/15

N2 - The subsurface flow within the subantarctic and subtropical regions around the Brazil-Malvinas (Falkland) Confluence Zone is studied, using daily hydrographic and kinematic data from four subsurface floats and a hydrographic section parallel to the South American shelf. The float trajectories are mapped against sea surface flow patterns as visible in concurrent satellite sea surface temperature (SST) images, with focus on the November 1994 and October/November 1995 periods. The unprecedented employment of Lagrangian θ-5 diagrams enables us to trace the advection of patches of fresh Antarctic Intermediate Water (AAIW) from the Confluence Zone into the subtropical region. The fresh AAIW consists of a mixture of subtropical AAIW and Malvinas Current core water. Within the subtropical gyre, these patches are discernible for extended periods and drift over long distances, reaching north to 34° S and east to 40° W. The cross-frontal migration of quasi-isobaric floats across the Confluence Zone from the subtropical to the subantarctic environment is observed on three occasions. The reverse process, float migration from a subpolar to a subtropical environment was observed once. These events were located near 40° S, 50° W, the site of a reoccurring cold core feature. Subsurface float and SST data comparison reveals similarities with analogous observations made in the Gulf Stream [Rossby, 1996] where cross-frontal processes were observed close to meander crests. The limited number of floats of this study and the complex structure of the Brazil-Malvinas Confluence Zone, however, restricts the analysis to a description of two events.

AB - The subsurface flow within the subantarctic and subtropical regions around the Brazil-Malvinas (Falkland) Confluence Zone is studied, using daily hydrographic and kinematic data from four subsurface floats and a hydrographic section parallel to the South American shelf. The float trajectories are mapped against sea surface flow patterns as visible in concurrent satellite sea surface temperature (SST) images, with focus on the November 1994 and October/November 1995 periods. The unprecedented employment of Lagrangian θ-5 diagrams enables us to trace the advection of patches of fresh Antarctic Intermediate Water (AAIW) from the Confluence Zone into the subtropical region. The fresh AAIW consists of a mixture of subtropical AAIW and Malvinas Current core water. Within the subtropical gyre, these patches are discernible for extended periods and drift over long distances, reaching north to 34° S and east to 40° W. The cross-frontal migration of quasi-isobaric floats across the Confluence Zone from the subtropical to the subantarctic environment is observed on three occasions. The reverse process, float migration from a subpolar to a subtropical environment was observed once. These events were located near 40° S, 50° W, the site of a reoccurring cold core feature. Subsurface float and SST data comparison reveals similarities with analogous observations made in the Gulf Stream [Rossby, 1996] where cross-frontal processes were observed close to meander crests. The limited number of floats of this study and the complex structure of the Brazil-Malvinas Confluence Zone, however, restricts the analysis to a description of two events.

UR - http://www.scopus.com/inward/record.url?scp=0033567609&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0033567609&partnerID=8YFLogxK

M3 - Article

VL - 104

SP - 21063

EP - 21082

JO - Journal of Geophysical Research: Oceans

JF - Journal of Geophysical Research: Oceans

SN - 2169-9275

IS - C9

M1 - 1999JC900059

ER -