A high‐resolution simulation of the ocean during the POMME experiment: Simulation results and comparison with observations

Paci, Alexandre

doi:10.1029/2004jc002712

Cited by 33 publications

(57 citation statements)

References 50 publications

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“…Our eddy-admitting model shows that eddies have a strong impact on the ML properties (also shown for mode water formation in the north Atlantic, e.g. Paci et al 2005), but eddy mixing also aids in generating homogeneous mode water characteristics in the interior of the subtropical gyre.…”

Section: Conclusion/discussionmentioning

confidence: 96%

Origin and mechanism of Subantarctic Mode Water formation and transformation in the Southern Indian Ocean

et al. 2010

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International audienceThe sources and pathways of mode waters and lower thermocline waters entering the subtropical gyre of the Indian Ocean are examined. A Lagrangian analysis is performed on an eddy-admitting simulation of the Global Ocean performed by the DRAKKAR Group (NEMO/OPA), which captures the main observed features. We trace the subducted mode water's pathways, identify their formation regions and trace whether their source waters come from the Atlantic, Pacific or Indian sectors of the Southern Ocean. Three main sites for mode waters ventilation in the Indian sector are identified with different circulation pathways and source water masses: (a) just north of Kerguelen, where 4.2 Sv of lighter Subantarctic Mode Waters (SAMW); σ 0 ∼ 26.5) are exported--originating in the Atlantic and Agulhas Retroflection regions; (b) SW of Australia, where 6.5 Sv of medium SAMW (σ 0 ∼ 26.6) are ventilated--originating in the southern and denser Agulhas Retroflection region; (c) SW of Tasmania and along the South Australian coast, where 3 Sv of denser SAMW (σ 0 ∼ 26.75) are ventilated--originating from three sources: Leeuwin Current waters, Tasman Sea (Pacific) waters and Antarctic Surface Waters. In all cases, modelled mode waters were last ventilated in the Indian Ocean just north of the deepest winter-mixed layers. For the waters subducted SW of Australia, the last ventilation site extends even further north. Waters ventilated in the deepest mixed layers north of the Subantarctic Front are then re-ventilated 5 years later southwest of Australia. The model results raise new hypotheses that revisit the classical picture of the SAMW formation and transformation, where a large homogeneous mixed layer is subducted and 'slides' equatorward, essentially maintaining the T/S characteristics acquired at the surface. Firstly, the last ventilation of the modelled mode waters is not in the region of the deepest mixed layers, as previously thought, but further north in regions of moderate meso-scale eddy activity. Secondly, the model shows for the first time a significant source region for Indian Ocean mode waters coming from deep winter-mixed layers along the south Australian coast. Finally, this analysis shows how the mode water characteristics are modified after subduction, due to internal eddy mixing. The simulation shows that resolved eddies have a strong impact on the mixed layer properties and that isopycnal eddy mixing also contributes to the generation of more homogeneous mode water characteristics in the interior

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Section: Conclusion/discussionmentioning

confidence: 96%

Origin and mechanism of Subantarctic Mode Water formation and transformation in the Southern Indian Ocean

et al. 2010

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“…The present paper focuses on the possible origin of aggregates and the relationship between their spatial variability and mesoscale physical features. Field sampling and mesoscale modeling simulations have shown that the POMME area contains significant mesoscale and submesoscale features, such as filaments located at fronts between mesoscale eddies Paci et al 2005). In this physical context, we propose here that downward particle export in a mesoscale context is restricted to relatively small zones, challenging the idea of a wide collection area for deep sediment traps.…”

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confidence: 86%

Vertical distribution of aggregates (>110 µm) and mesoscale activity in the northeastern Atlantic: Effects on the deep vertical export of surface carbon

Guidi

Stemmann

Legendre

et al. 2007

Limnology & Oceanography

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Spatial and temporal variability in the distribution of marine aggregates (.110 mm) was studied using underwater video profilers in an area off the Iberian Peninsula and Azores Islands dominated by mesoscale and submesocale hydrodynamics in winter, spring, and summer 2001. In the 0-200-m layer, aggregates were most abundant in spring (100-120 mg dry weight [dry wt] m 23 ) and lowest during summer and winter (1-10 mg dry wt m 23 ). In the deeper layers (down to 1,000 m), the seasonal pattern was different, with concentrations highest in spring and summer, and lowest in winter (e.g., at 800 m, 5-10 mg dry wt m 23 in spring and summer; 1-5 mg dry wt m 23 in winter). The seasonal change in the abundance of aggregates in the upper 1,000 m was consistent with changes in the composition and intensity of the particulate flux recorded in sediment traps and with seasonal changes in the surface phytoplankton community. In an area dominated by eddies, surface accumulation of aggregates and export down to 1,000 m occur at mesoscale distances (,100 km). The occurrence of a rich aggregate layer may be related to mesoscale activity in water flow that drives nutrient inputs, phytoplankton production, and the formation of large aggregates. Such spatially constrained zones of massive export may be typical of frontal open-sea systems, and may have been missed by conventional sediment trap moorings, which cannot resolve export at this mesoscale level.

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“…This correction greatly improves the coherence between the hydrological fields, the ML and the air‐sea fluxes, although it neglects the effect of advection. Incidentally, this correction was found to slightly decrease the correlation between observed and simulated horizontal fields, and was therefore not used by Paci et al [2005]. Interpolation to the model grid is performed from objective analysis of the individual profiles, with an influence radius of 50 km as described by Paci et al [2005].…”

Section: Programme Océan Multidisciplinaire Méso Echelle (Pomme) Surveysmentioning

confidence: 99%

“…The model is initialized using the data from the first leg of P1 (P1L1), and is validated using data of P1L2, P2L1 and P2L2. A careful validation of the model dynamics and thermodynamics is presented by Paci et al [2005]. The objective of this study is twofold.…”

Section: Introductionmentioning

confidence: 99%

A four‐dimensional mesoscale map of the spring bloom in the northeast Atlantic (POMME experiment): Results of a prognostic model

et al. 2005

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[1] A prognostic high-resolution model is established to provide an integrated view of the evolution of the spring bloom during the Programme Océan Multidisciplinaire Méso Echelle (POMME) experiments carried out at sea from February to May 2001 (16-22°W and 38°-45°N). Data collected during the first survey were used for model initialization, and data from three other cruises were used for model validation. The model successfully predicts the time evolution of the main reservoirs and fluxes, except for a storm event during postbloom conditions, for which the biological impact is underestimated. The bloom is long in duration (2 months), has low intensity (1 mg Chl m À3 ), and is characterized by a small f-ratio (0.45) and a small e-ratio (0.05). Furthermore, the model reveals much stronger space and time variability than sampled in the data. This large variability results both from the synoptic atmospheric variability and from the stirring induced by oceanic mesoscale eddies. In particular, the bloom starts in specific submesoscale features that correspond to filaments of minimum mixed layer depth. On short timescales (2-3 days), space and time variability have the same order of magnitude. On the seasonal timescale, time variability is larger than space variability. Considering the transient state of the system, this modeling exercise is also used to quantify the nonsynopticity of the observations, which occur mostly during bloom conditions, a crucial point for the data interpretation.

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A high‐resolution simulation of the ocean during the POMME experiment: Simulation results and comparison with observations

Cited by 33 publications

References 50 publications

Origin and mechanism of Subantarctic Mode Water formation and transformation in the Southern Indian Ocean

Origin and mechanism of Subantarctic Mode Water formation and transformation in the Southern Indian Ocean

Vertical distribution of aggregates (>110 µm) and mesoscale activity in the northeastern Atlantic: Effects on the deep vertical export of surface carbon

A four‐dimensional mesoscale map of the spring bloom in the northeast Atlantic (POMME experiment): Results of a prognostic model

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