A General-Coordinate, Nonlocal Neutral Diffusion Operator

Andrew E. Shao, Alistair Adcroft, Robert Hallberg, Stephen M. Griffies

Research output: Contribution to journalArticlepeer-review

4 Scopus citations


We present a neutral diffusion operator appropriate for an ocean model making use of general vertical coordinates. The diffusion scheme uses polynomial reconstructions in the vertical, along with a horizontally local but vertically nonlocal stencil for estimates of tracer fluxes. These fluxes are calculated on a vertical grid that is the superset of model columns in a neutral density space. Using flux-limiters, the algorithm dissipates tracer extrema locally, and no new extrema are created. A demonstration using a linear equation of state in an idealized configuration shows that the algorithm is perfectly neutral. When using the nonlinear TEOS-10 equation of state with a constant reference pressure, the algorithm compares nearly exactly to a case discretized onto isopycnal surfaces and using along-layer diffusion. The algorithm's cost is comparable to that of tracer advection and can be readily implemented into ocean general circulation models.

Original languageEnglish (US)
Article numbere2019MS001992
JournalJournal of Advances in Modeling Earth Systems
Issue number12
StatePublished - Dec 2020

All Science Journal Classification (ASJC) codes

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


  • diffusion operator
  • neutral physics
  • ocean model discretization


Dive into the research topics of 'A General-Coordinate, Nonlocal Neutral Diffusion Operator'. Together they form a unique fingerprint.

Cite this