Long-Term Monitoring of the Brazil Current Transport at 22°S From XBT and Altimetry Data: Seasonal, Interannual, and Extreme Variability

M. Goes, M. Cirano, M. M. Mata, S. Majumder

Research output: Contribution to journalArticlepeer-review

8 Scopus citations

Abstract

The seasonal and interannual variability of the Brazil Current (BC) at 22°S is examined using expendable bathythermograph (XBT) transect and satellite altimetry data from 1993 to 2017. The XBT-based mean absolute geostrophic transport of the BC is estimated as 4.7 ± 1.9 Sv, with additional 0.9 ± 0.9 Sv along the shelf. The strong agreement between the absolute dynamic height and altimetric sea surface height is used in two methods to reconstruct a daily time series of the BC transport since 1993. The altimetry-based methods can represent well the BC transport seasonal cycle, whereas the XBT-based estimates are slightly aliased by the strong regional mesoscale variability. At interannual timescales, the BC transport is significantly correlated (r = 0.43) with the wind stress curl in the western half of the basin with a lag of 19 months, which is consistent with baroclinic adjustment timescales. Other sources of variability can be observed in a case study of the summer 2009/2010 event, which was characterized by strong sea surface temperature anomalies of approximately 3 °C. During the event, the BC reached 11 Sv for nearly 3 months, partly driven by an increased coastal upwelling from a cyclonic wind stress anomaly, a standing eddy along the section, and thermosteric anomalies that reached the offshore side of section in February. Heat anomalies were transported southward along the subtropical gyre following the BC path in a period of 2 months, which is consistent with advective timescales. Potential implications for extreme sea level and summer precipitation events in South America are discussed.

Original languageEnglish (US)
Pages (from-to)3645-3663
Number of pages19
JournalJournal of Geophysical Research: Oceans
Volume124
Issue number6
DOIs
StatePublished - Jun 2019

Keywords

  • boundary current
  • coastal sea level
  • coastal upwelling
  • marine heat wave
  • ocean advection
  • Sverdrup balance

ASJC Scopus subject areas

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

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