Challenges and Prospects in Ocean Circulation Models

Abstract

We revisit the challenges and prospects for ocean circulation models following Griffies et al. (2010). Over the past decade, ocean circulation models evolved through improved understanding, numerics, spatial discretization, grid configurations, parameterizations, data assimilation, environmental monitoring, and process-level observations and modeling. Important large scale applications over the last decade are simulations of the Southern Ocean, the Meridional Overturning Circulation and its variability, and regional sea level change. Submesoscale variability is now routinely resolved in process models and permitted in a few global models, and submesoscale effects are parameterized in most global models. The scales where nonhydrostatic effects become important are beginning to be resolved in regional and process models. Coupling to sea ice, ice shelves, and high-resolution atmospheric models has stimulated new ideas and driven improvements in numerics. Observations have provided insight into turbulence and mixing around the globe and its consequences are assessed through perturbed physics models. Relatedly, parameterizations of the mixing and overturning processes in boundary layers and the ocean interior have improved. New diagnostics being used for evaluating models Fox-Kemper et al. Ocean Circulation Models alongside present and novel observations are briefly referenced. The overall goal is summarizing new developments in ocean modeling, including: how new and existing observations can be used, what modeling challenges remain, and how simulations can be used to support observations.

Simulating the Midlatitude Atmospheric Circulation: What Might We Gain From High-Resolution Modeling of Air-Sea Interactions?

“…We refer throughout this paper to the Bmesoscale^as the range of horizontal scale within 10-100 km which is starting to be resolved in global coupled seasonal forecasting systems but not yet in global coupled climate models used for climate change predictions. This corresponds to a dynamical regime where, in the extra-tropics, the Rossby number 2 is on the order of unity in the atmosphere ( [23,24], in agreement with their Badvective regime^), but is smaller than unity in the ocean [25].…”

Impact of horizontal resolution on global ocean-sea-ice model simulations based on the experimental protocols of the Ocean Model Intercomparison Project phase 2 (OMIP-2)

“…Here these metrics are assessed in a suite of 4 pairs of low-resolution, high-resolution ocean and sea-ice models forced with the latest JRA55-do dataset (Tsujino et al, 2019). These results will provide a useful baseline for future process-focused analyses as well as ocean model development activities at diverse resolutions.…”

The Atlantic Meridional Overturning Circulation in High‐Resolution Models

“…Any shortcoming in the representation of the AMOC should not be considered in isolation. Instead, it will generally be symptomatic of a variety of model deficiencies (Fox‐Kemper et al, 2019) that in turn lead to an unrealistic representation of the water masses in the global ocean that will affect the force balances governing the AMOC (and more generally the global MOC). Of course an AMOC which is either too weak/strong or too shallow/deep can itself be the cause of unrealistic water mass properties; however, there are other contributing factors.…”