The Kinematic Similarity of Two Western Boundary Currents Revealed by Sustained High-Resolution Observations

M. R. Archer, S. R. Keating, M. Roughan, W. E. Johns, R. Lumpkin, F. J. Beron-Vera, L. K. Shay

Research output: Contribution to journalLetter

9 Scopus citations

Abstract

Western boundary currents (WBCs) modulate the global climate and dominate regional ocean dynamics. Despite their importance, few direct comparisons of the kinematic structure of WBCs exist, due to a lack of equivalent sustained observational data sets. Here we compare multiyear, high-resolution observations (1 km, hourly) of surface currents in two WBCs (Florida Current and East Australian Current) upstream of their separation point. Current variability is dominated by meandering, and the WBCs exhibit contrasting time-mean velocities in a Eulerian coordinate frame. By transforming to a jet-following coordinate frame, we show that the time-mean surface velocity structure of the WBC jets is remarkably similar, considering their distinct local wind, bathymetry, and meandering signals. Both WBCs show steep submesoscale kinetic energy wavenumber spectra with weak seasonal variability, in contrast to recent findings in other ocean regions. Our results suggest that it is the mesoscale flow field that controls mixing and ocean dynamics in these regions.

Original languageEnglish (US)
Pages (from-to)6176-6185
Number of pages10
JournalGeophysical Research Letters
Volume45
Issue number12
DOIs
StatePublished - Jun 28 2018

Keywords

  • East Australian Current
  • Florida Current (Gulf Stream)
  • eddy kinetic energy (EKE)
  • high-frequency (HF) radar
  • jet (stream) coordinate frame
  • submesoscale turbulence

ASJC Scopus subject areas

  • Geophysics
  • Earth and Planetary Sciences(all)

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