Atmosphere Ocean Science Colloquium

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The mesoscale dominance hypothesis: a new simulation regime for ocean climate models

Speaker: Steve Griffies, Geophysical Fluid Dynamics Laboratory

Location: Warren Weaver Hall 1302

Date: Wednesday, October 16, 2024, 3:30 p.m.

Synopsis:

We propose the following three ocean model properties are necessary to realize a thermally equilibrated pre-industrial climate simulation with ocean heat content consistent with the amount of anthropogenic heat input to the ocean since 1860, and with a thermal equilibration time on the order of 150 years rather than millennia. First, we need accurate ocean mesoscale transport via explicit representation or a parameterization.  Second, we need accurate parameterization of diapycnal processes associated with small scale turbulent mixing. Third, we need to maintain negligible spurious numerical diapycnal mixing, thus allowing for the interior mixing of water masses to be determined by physics rather than corrupted by numerics. We refer to such ocean models as mesoscale dominant.  In support of this hypothesis, this talk introduces some concepts and methods related to the vertical Lagrangian remapping approach to numerical ocean modeling, while also illustrating climate model simulations that approach the mesoscale dominant regime.