Influence of numerical schemes on current-topography interactions  in 1/4° global ocean simulations

Penduff, Thierry; Sommer, Julien Le; Barnier, Bernard; Tréguier, Anne‐Marie; Molines, Jean‐Marc; Madec, Gurvan

doi:10.5194/os-3-509-2007

Cited by 103 publications

(61 citation statements)

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“…Indeed, the transports are comparable in both configurations but the currents are much more vigorous in the eddy-permitting configuration. Barnier et al (2006), Penduff et al (2007) and Le Sommer et al (2009) show how the use of an energy-and enstrophyconserving momentum advection scheme in NEMO at 1/4 • yielded a clear improvement in the simulation of currenteddy-topography interactions, and thus of along-topography circulations. Comparisons between a large current meter database (Holloway, 2008) and two DRAKKAR global ocean simulations (T. Penduff, personal communication, 2009) confirm that increasing NEMO's resolution from 2 • to 1/4 • yields a large reduction of local model-observation mismatches, both in terms of mean current strengths (which increase toward observed levels) and directions (aligning with measured flows more nearly along isobaths), in particular along basin margins where many current meters are located.…”

Section: Description Of the Model And ε Nd Modelingmentioning

confidence: 97%

Modeling the Nd isotopic composition in the North Atlantic basin using an eddy-permitting model

et al. 2010

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Abstract. Boundary Exchange (BE -exchange of elements between continental margins and the open ocean) has been emphasized as a key process in the oceanic cycle of neodymium (Nd) (Lacan and Jeandel, 2005a). Here, we use a regional eddy-permitting resolution Ocean General Circulation Model (1/4 • ) of the North Atlantic basin to simulate the distribution of the Nd isotopic composition, considering BE as the only source. Results show good agreement with the data, confirming previous results obtained using the same parameterization of the source in a coarse resolution global model , and therefore the major control played by the BE processes in the Nd cycle on the regional scale. We quantified the exchange rate of the BE, and found that the time needed for the continental margins to significantly imprint the chemical composition of the surrounding seawater (further referred as characteristic exchange time) is of the order of 0.2 years. However, the timescale of the BE may be subject to large variations as a very short exchange time (a few days) is needed to reproduce the highly negative values of surface waters in the Labrador Sea, whereas a longer one (up to 0.5 years) is required to simulate the radiogenic influence of basaltic margins and distinguish the negative isotopic signatures of North Atlantic Deep Water from the more radiogenic southern origin water masses. This likely represents geographical variations in erosion fluxes and the subsequent particle load onto the continental margins. Although the parameterization of the BE is the same in both configurations of the model, the characteristic exchange time in the eddy-permitting configuration is significantly lower than the previous evaluations using a low Correspondence to: T. Arsouze (arsouze@ldeo.columbia.edu) resolution configuration (6 months to 10 years), but however in agreement with the available seawater Nd isotope data. This results highlights the importance of the model dynamics in simulating the BE process.

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Section: Description Of the Model And ε Nd Modelingmentioning

confidence: 97%

Modeling the Nd isotopic composition in the North Atlantic basin using an eddy-permitting model

et al. 2010

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“…PISCES is currently embedded into two modeling systems: NEMO (Madec, 2008) and ROMS_AGRIF (Penven et al, 2006;Debreu et al, 2011). It can be downloaded from their respective web sites:…”

Section: O Aumont Et Al: a Description Of Pisces-v2mentioning

confidence: 99%

“…The spatial resolution is about 2 • by 2 • cos (where is the latitude) with a focusing of the meridional resolution to 0.5 • in the equatorial domain. The model has 30 vertical layers, with an increased vertical thickness from 10 m at the surface to 500 m at 5000 m. Representation of the topography is based on the partial step thicknesses Penduff et al, 2007). Lateral mixing along isopycnal surfaces is performed both on tracers and momentum as in Lengaigne et al (2003).…”

Section: Model Setupmentioning

confidence: 99%

PISCES-v2: an ocean biogeochemical model for carbon and ecosystem studies

Aumont¹,

et al. 2015

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Abstract. PISCES-v2 (Pelagic Interactions Scheme for Carbon and Ecosystem Studies volume 2) is a biogeochemical model which simulates the lower trophic levels of marine ecosystems (phytoplankton, microzooplankton and mesozooplankton) and the biogeochemical cycles of carbon and of the main nutrients (P, N, Fe, and Si). The model is intended to be used for both regional and global configurations at high or low spatial resolutions as well as for short-term (seasonal, interannual) and long-term (climate change, paleoceanography) analyses. There are 24 prognostic variables (tracers) including two phytoplankton compartments (diatoms and nanophytoplankton), two zooplankton size classes (microzooplankton and mesozooplankton) and a description of the carbonate chemistry. Formulations in PISCES-v2 are based on a mixed Monod-quota formalism. On the one hand, stoichiometry of C / N / P is fixed and growth rate of phytoplankton is limited by the external availability in N, P and Si. On the other hand, the iron and silicon quotas are variable and the growth rate of phytoplankton is limited by the internal availability in Fe. Various parameterizations can be activated in PISCES-v2, setting, for instance, the complexity of iron chemistry or the description of particulate organic materials. So far, PISCES-v2 has been coupled to the Nucleus for European Modelling of the Ocean (NEMO) and Regional Ocean Modeling System (ROMS) systems. A full description of PISCES-v2 and of its optional functionalities is provided here. The results of a quasi-steady-state simulation are presented and evaluated against diverse observational and satellite-derived data. Finally, some of the new functionalities of PISCES-v2 are tested in a series of sensitivity experiments.

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“…Barnier et al, 2006;Penduff et al, 2007Penduff et al, , 2010Treguier et al, 2014;Marzocchi et al, 2015). The FRM at 1/4 • horizontal resolution is referred to here as ORCA025 and has 46 z levels, with thickness ranging from 6 m at the surface to 250 m at the ocean bottom.…”

Section: Free-running Modelsmentioning

confidence: 99%

South Atlantic meridional transports from NEMO-based simulations and reanalyses

2018

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Abstract. The meridional heat transport (MHT) of the South Atlantic plays a key role in the global heat budget: it is the only equatorward basin-scale ocean heat transport and it sets the northward direction of the global cross-equatorial transport. Its strength and variability, however, are not well known. The South Atlantic transports are evaluated for four state-of-the-art global ocean reanalyses (ORAs) and two free-running models (FRMs) in the period 1997-2010. All products employ the Nucleus for European Modelling of the Oceans (NEMO) model, and the ORAs share very similar configurations. Very few previous works have looked at ocean circulation patterns in reanalysis products, but here we show that the ORA basin interior transports are consistently improved by the assimilated in situ and satellite observations relative to the FRMs, especially in the Argo period. The ORAs also exhibit systematically higher meridional transports than the FRMs, which is in closer agreement with observational estimates at 35 and 11 • S. However, the data assimilation impact on the meridional transports still greatly varies among the ORAs, leading to differences up to ∼ 8 Sv and 0.4 PW in the South Atlantic Meridional Overturning Circulation and the MHTs, respectively. We narrow this down to large inter-product discrepancies in the western boundary currents (WBCs) at both upper and deep levels explaining up to ∼ 85 % of the inter-product differences in MHT. We show that meridional velocity differences, rather than temperature differences, in the WBCs drive ∼ 83 % of this MHT spread. These findings show that the present ocean observation network and data assimilation schemes can be used to consistently constrain the South Atlantic interior circulation but not the overturning component, which is dominated by the narrow western boundary currents. This will likely limit the effectiveness of ORA products for climate or decadal prediction studies.

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Influence of numerical schemes on current-topography interactions in 1/4° global ocean simulations

Cited by 103 publications

References 50 publications

Modeling the Nd isotopic composition in the North Atlantic basin using an eddy-permitting model

Modeling the Nd isotopic composition in the North Atlantic basin using an eddy-permitting model

PISCES-v2: an ocean biogeochemical model for carbon and ecosystem studies

South Atlantic meridional transports from NEMO-based simulations and reanalyses

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