Comparing Ocean Surface Boundary Vertical Mixing Schemes Including Langmuir Turbulence

Qing Li, Brandon G. Reichl, Baylor Fox-Kemper, Alistair J. Adcroft, Stephen E. Belcher, Gokhan Danabasoglu, Alan L.M. Grant, Stephen M. Griffies, Robert Hallberg, Tetsu Hara, Ramsey R. Harcourt, Tobias Kukulka, William G. Large, James C. McWilliams, Brodie Pearson, Peter P. Sullivan, Luke Van Roekel, Peng Wang, Zhihua Zheng

Research output: Contribution to journalArticlepeer-review

66 Scopus citations

Abstract

Six recent Langmuir turbulence parameterization schemes and five traditional schemes are implemented in a common single-column modeling framework and consistently compared. These schemes are tested in scenarios versus matched large eddy simulations, across the globe with realistic forcing (JRA55-do, WAVEWATCH-III simulated waves) and initial conditions (Argo), and under realistic conditions as observed at ocean moorings. Traditional non-Langmuir schemes systematically underpredict large eddy simulation vertical mixing under weak convective forcing, while Langmuir schemes vary in accuracy. Under global, realistic forcing Langmuir schemes produce 6% (−1% to 14% for 90% confidence) or 5.2 m (−0.2 m to 17.4 m for 90% confidence) deeper monthly mean mixed layer depths than their non-Langmuir counterparts, with the greatest differences in extratropical regions, especially the Southern Ocean in austral summer. Discrepancies among Langmuir schemes are large (15% in mixed layer depth standard deviation over the mean): largest under wave-driven turbulence with stabilizing buoyancy forcing, next largest under strongly wave-driven conditions with weak buoyancy forcing, and agreeing during strong convective forcing. Non-Langmuir schemes disagree with each other to a lesser extent, with a similar ordering. Langmuir discrepancies obscure a cross-scheme estimate of the Langmuir effect magnitude under realistic forcing, highlighting limited understanding and numerical deficiencies. Maps of the regions and seasons where the greatest discrepancies occur are provided to guide further studies and observations.

Original languageEnglish (US)
Pages (from-to)3545-3592
Number of pages48
JournalJournal of Advances in Modeling Earth Systems
Volume11
Issue number11
DOIs
StatePublished - Nov 1 2019

All Science Journal Classification (ASJC) codes

  • Global and Planetary Change
  • Environmental Chemistry
  • General Earth and Planetary Sciences

Keywords

  • JRA55-do
  • Langmuir turbulence
  • ocean surface boundary layer
  • parameterization
  • turbulent mixing

Fingerprint

Dive into the research topics of 'Comparing Ocean Surface Boundary Vertical Mixing Schemes Including Langmuir Turbulence'. Together they form a unique fingerprint.

Cite this