Modified (hyper-)viscosity for coarse-resolution ocean models

TL;DR

This paper introduces a simple, computationally efficient parameterization that modifies viscosity in coarse-resolution ocean models to better replicate high-resolution results, improving energy and variability statistics.

Contribution

A novel viscosity modification scheme for coarse ocean models that enhances accuracy without high computational costs.

Findings

Significant improvement in energy statistics

Enhanced intrinsic variability on coarse meshes

Effective reproduction of high-resolution mean quantities

Abstract

We present a simple parameterization for coarse-resolution ocean models. To replace computationally expensive high-resolution ocean models, we develop a computationally cheap parameterization for coarse-resolution models based solely on the modification of the viscosity term in advection equations. It is meant to reproduce the mean quantities like pressure, velocity, or vorticity computed from a high-resolution reference solution or using observations. We test this new parameterization on a double-gyre quasi-geostrophic model in the eddy-permitting regime. Our results show that the proposed scheme improves significantly the energy statistics and the intrinsic variability on the coarse mesh. This method shall serve as a deterministic basis model for coarse-resolution stochastic parameterizations in future works.