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AGU: Geophysical Research Letters

 

Keywords

  • argo flaots
  • diapycnal mixing
  • internal waves
  • near-inertial waves
  • rough topography

Index Terms

  • 4568 - Turbulence, diffusion, and mixing processes

Paper in Press

GEOPHYSICAL RESEARCH LETTERS, doi:10.1029/2012GL053196

Spatial and temporal variability of global ocean mixing inferred from Argo profiles

Key Points
  • Argo floats can be used to estimate the turbulent mixing in the global ocean
  • Spatial patterns of mixing are apparent (e.g. elevation over rough topography)
  • Temporal patterns of mixing are also apparent (e.g. seasonal cycles)

Authors:

Caitlin Whalen

Lynne D. Talley

Jennifer A MacKinnon

The influence of turbulent ocean mixing transcends its inherently small scales to affect large scale ocean processes including water-mass transformation, stratification maintenance, and the overturning circulation. However, the distribution of ocean mixing is not well described by sparse ship-based observations since this mixing is both spatially patchy and temporally intermittent. We use strain information from Argo float profiles in the upper 2,000 m of the ocean to generate over 400,000 estimates of the energy dissipation rate, indicative of ocean mixing. These estimates rely on numerous assumptions, and do not take the place of direct measurement methods. Temporally averaged estimates reveal clear spatial patterns in the parameterized dissipation rate and diffusivity distribution across all the oceans. They corroborate previous observations linking elevated dissipation rates to regions of rough topography. We also observe heightened estimated dissipation rates in areas of high eddy kinetic energy, as well as heightened diffusivity in high latitudes where stratification is weak. The seasonal dependence of mixing is observed the Northwest Pacific, suggesting a wind-forced response in the upper ocean.

Received 19 July 2012; accepted 27 August 2012.

Citation: Whalen, C., L. D. Talley, and J. A. MacKinnon (2012), Spatial and temporal variability of global ocean mixing inferred from Argo profiles, Geophys. Res. Lett., doi:10.1029/2012GL053196, in press.