Impact of partial steps and momentum advection schemes in a global ocean circulation model at eddy-permitting resolution

By Barnier Bernard, Gurvan Madec, T. Penduff, J. Molines, A. Treguier, J. Sommer, A. Beckmann, Arne Biastoch, C. Böning, J. Dengg and 9 more. 2006

692 citations recorded by the source corpus.

Series of sensitivity tests were performed with a z-coordinate, global eddy-permitting (1/4°) ocean/sea-ice model (the ORCA-R025 model configuration developed for the DRAKKAR project) to carefully evaluate the impact of recent state-of-the-art numerical schemes on model solutions. The combination of an energy–enstrophy conserving (EEN) scheme for momentum advection with a partial step (PS) representation of the bottom topography yields significant improvements in the mean circulation. Well known biases in the representation of western boundary currents, such as in the Atlantic the detachment of the Gulf Stream, the path of the North Atlantic Current, the location of the Confluence, and the strength of the Zapiola Eddy in the south Atlantic, are partly corrected. Similar improvements are found in the Pacific, Indian, and Southern Oceans, and characteristics of the mean flow are generally much closer to observations. Comparisons with other state-of-the-art models show that the ORCA-R025 configuration generally performs better at similar resolution. In addition, the model solution is often comparable to solutions obtained at 1/6 or 1/10° resolution in some aspects concerning mean flow patterns and distribution of eddy kinetic energy. Although the reasons for these improvements are not analyzed in detail in this paper, evidence is shown that the combination of EEN with PS reduces numerical noise near the bottom, which is likely to affect current–topography interactions in a systematic way. We conclude that significant corrections of the mean biases presently seen in general circulation model solutions at eddy-permitting resolution can still be expected from the development of numerical methods, which represent an alternative to increasing resolution.

Subfields: Global and Planetary Change, Oceanography

View Paper: https://www.semanticscholar.org/paper/fa6083f808f853b5885401c39ef9a5c43eff7d18

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Citations in the corpus

Causes of Interannual–Decadal Variability in the Meridional Overturning Circulation of the Midlatitude North Atlantic Ocean (2008, background): “The better representation of topographic slopes in combination with a refined, energyand enstrophy-conserving advection scheme (an adaptation of Arakawa and Lamb 1981) were found to led to marked improvements in various circulation features (Barnier et al. 2006; Le Sommer et al. 2008).”
Evaluation of CMIP6 DECK Experiments With CNRM‐CM6‐1 (2019, methodology): “CNRM‐CM6‐1 resolves ocean dynamics on 75 vertical levels using a vertical z coordinate with partial step bathymetry formulation (Barnier et al., 2009). The model layer thickness increases from 1m near the surface to 200 m at a depth of 6,000 m. The time step is 30 min. At the surface, the model uses”
Presentation and Evaluation of the IPSL‐CM6A‐LR Climate Model (2020, positive): “Vertical discretization uses a partial step formulation (Barnier et al., 2006), which ensures a better representation of bottom bathymetry, with 75 levels.”
The CNRM-CM5.1 global climate model: description and basic evaluation (2013, methodology): “In the vertical, 42 levels are used (from 10 m at the surface, to 25 at 100 m, 130 at 600 m, and 300 at 5,000 m) and a partial step formulation (Barnier et al. 2006; Penduff et al. 2007) is applied to the thickness of the bottom layer.”
Sea Level Expression of Intrinsic and Forced Ocean Variabilities at Interannual Time Scales (2011, background): “Details about these local biases, which are often present in higher-resolution simulations as well, may be found in Barnier et al. (2006).”
The Louvain-La-Neuve sea ice model LIM3.6: global and regional capabilities (2015, methodology): “The simulation is forced at the surface by 6-hourly, 3/4° x 3/4° ERAI dataset, and at the boundaries by 5-days outputs from a DRAKKAR 1/4° global reference simulation ORCA025-MJM (an update to ORCA025-G70; Barnier et al., 2006; Molines et al., 2007; Drakkar group, 2007).”
A global wave parameter database for geophysical applications. Part 1: Wave-current turbulence interaction parameters for the open ocean based on traditional parameterizations (2008, methodology): “A preliminary analysis using 0.5 surface current fields from Mercator’s PSY3V1 model (Barnier et al., 2006) shows that in the equatorial region, where the yearly average current can exceed 7% of the average wind velocity, currents have a significant impact on Hs (Fig.”
Evaluation of the CMCC eddy‐permitting global ocean physical reanalysis system (C‐GLORS, 1982–2012) and its assimilation components (2016, background): “The model has 50 vertical depth levels with partial steps (Barnier et al., 2006).”