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| Dufois, Francois; Lowe, Ryan J.; Rayson, Matthew D.; Branson, Paul M.. |
| Owing to their strong forcing of the ocean surface, tropical cyclones strongly modify the hydrodynamics of Australia's North West Shelf (one of the world's tropical cyclone hotspots), which in turn plays a dominant role in its sediment dynamics. Previous modeling studies have focused on describing the short term sediment dynamics during individual tropical cyclones, but have lacked validation of the responses using field observations. As a consequence, the long term cumulative impact of the tropical cyclones on the residual sediment transport pathways at the shelf scale remains unclear. In this study we apply a sediment transport model over the North West Shelf, validate its performance using an extensive field dataset, and implement a 14 year‐long model... |
| Tipo: Text |
Palavras-chave: ROMS; COAWST; Sediment transport model; Tropical cyclone; Surface waves; Sediment pathways. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00449/56078/57601.pdf |
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| Couvelard, Xavier; Messager, Christophe; Penven, Pierrick; Smet, Sébastien; Lattes, Philippe. |
| The oceanic circulation south of Africa is characterised by a complex dynamics with a strong variability due to the presence of the Agulhas current and numerous eddies. This area of interest is also the location of several natural gas fields under seafloor which are targeted for drilling and exploitation. The complex and powerful ocean currents induces significant issues for ship operations at the surface as well as under the surface for deep sea operations. Therefore, the knowledge of the state of the currents and the ability to forecast them in a realistic manners could greatly enforce the safety of various marine operation. Following this objective, an array of HF radar systems were deployed to allow a detailed knowledge of the Agulhas currents and its... |
| Tipo: Text |
Palavras-chave: 4DVAR; Agulhas current; HF radar; ROMS; Forecast. |
| Ano: 2021 |
URL: https://archimer.ifremer.fr/doc/00677/78929/81299.pdf |
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| Renosh, Pannimpullath R.; Jourdin, Frederic; Charantonis, Anastase A.; Yala, Khalil; Rivier, Aurelie; Badran, Fouad; Thiria, Sylvie; Guillou, Nicolas; Leckler, Fabien; Gohin, Francis; Garlan, Thierry. |
| Hydro-sedimentary numerical models have been widely employed to derive suspended particulate matter (SPM) concentrations in coastal and estuarine waters. These hydro-sedimentary models are computationally and technically expensive in nature. Here we have used a computationally less-expensive, well-established methodology of self-organizing maps (SOMs) along with a hidden Markov model (HMM) to derive profiles of suspended particulate inorganic matter (SPIM). The concept of the proposed work is to benefit from all available data sets through the use of fusion methods and machine learning approaches that are able to process a growing amount of available data. This approach is applied to two different data sets entitled “Hidden” and “Observable”. The hidden... |
| Tipo: Text |
Palavras-chave: Suspended particulate inorganic matter; Self-organizing maps; Hidden Markov Model; Machine learning; English Channel; ROMS. |
| Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00415/52653/53511.pdf |
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| Vic, Clement; Roullet, Guillaume; Carton, Xavier; Capet, X.. |
| The Great Whirl (GW) is a persistent anticyclonic mesoscale eddy that is observed seasonally in the Arabian Sea during a period embedding the 3 months of the southwest monsoon (June–July–August) at a quasi-steady location. Its dynamics remain unclear despite it being one of the largest coherent vortices in the world ocean. Realistic regional numerical experiments using ROMS are performed to investigate the life cycle of the GW, which is not well resolved by sparse available in situ measurements in the region. Using a set of sensitivity experiments and an accurate temporal characterization of the eddy properties (including position, radius, depth, and vorticity) we (i) confirm the role of basin-scale downwelling Rossby waves in the GW generation, (ii)... |
| Tipo: Text |
Palavras-chave: Arabian Sea; Indian Ocean; Great Whirl; Mesoscale dynamics; ROMS; Rossby waves. |
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00211/32197/30631.pdf |
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| Guillou, Nicolas; Rivier, Aurelie; Gohin, Francis; Chapalain, Georges. |
| The present study investigates the performances of the three-dimensional multicomponent hydro-sedimentary model ROMS (Regional Ocean Modeling System) to predict near-surface suspended sediment concentrations (SSC) in the English Channel (western Europe). Predictions are assessed against satellite-retrieved observations from raw MODIS and MERIS images for the year 2008 characterized by the highest availability of cloud-free data. Focus is put on improvements obtained with: (1) SSC inputs at the open boundaries; and (2) simple parameterizations of the settling velocity and the critical shear stress. Sensitivity studies confirm the importance of the advection of fine-grained suspended sediments in the central waters of the English Channel exhibiting benefits... |
| Tipo: Text |
Palavras-chave: ROMS; Satellite; MERIS; MODIS; Tide; Wave. |
| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00276/38766/37307.pdf |
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| Chevane, C. M.; Penven, Pierrick; Nehama, F. P. J.; Reason, C. J. C.. |
| The Sofala Bank, a wide shelf located along the central coast of Mozambique, hosts tides with high amplitudes. The Regional Ocean Modelling System (ROMS) was used to analyse the tidal currents on the bank and to investigate their effects on the stratification and generation of tidal fronts. During spring tides, barotropic tidal currents with maximum values ranging from 40 cm s–1 to 70 cm s–1 are found on the central bank. The major axis of the tidal ellipses for M2 and S2 follow a cross-shelf direction with mainly anticlockwise rotation. Similar to observations, three distinct regimes occur: (i) a warm well-mixed region on the inner shelf where the depths are <30 m; (ii) a wellmixed colder region above the shelf edge; and (iii) a stratified region... |
| Tipo: Text |
Palavras-chave: Barotropic tidal currents; ROMS; Sea surface temperature; Shallow seas; Tidal front. |
| Ano: 2016 |
URL: http://archimer.ifremer.fr/doc/00362/47276/47852.pdf |
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| Caballero, Ainhoa; Ferrer, Luis; Rubio, Anna; Charria, Guillaume; Taylor, Benjamin H.; Grima, Nicolas. |
| The presence of a quasi-stationary anticyclonic eddy within the southeastern Bay of Biscay (centred around 44°30′N-4°W) has been reported on various occasions in the bibliography. The analysis made in this study for the period 2003–2010, by using in situ and remote sensing measurements and model results shows that this mesoscale coherent structure is present almost every year from the end of winter-beginning of spring, to the beginning of fall. During this period it remains in an area limited to the east by the Landes Plateau, to the west by Le Danois Bank and Torrelavega canyon and to the northwest by the Jovellanos seamount. All the observations and analysis made in this contribution, suggest that this structure is generated between Capbreton and... |
| Tipo: Text |
Palavras-chave: Bay of Biscay; Eddies; SWODDIES; Topographic effects; Vortex; Mesoscale; Altimetry; Satellite oceanography; Drifters; ROMS. |
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00161/27260/25469.pdf |
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| Guillou, Nicolas; Rivier, Aurelie; Chapalain, Georges; Gohin, Francis. |
| Numerous ecological problems of continental shelf ecosystems require a refined knowledge of the evolution of suspended sediment concentrations (SSC). The present investigation focuses on the spatial and temporal variabilities of near-surface SSC in coastal waters of the English Channel (western Europe) by exploiting numerical predictions from the Regional Ocean Modeling System ROMS. Extending previous investigations of ROMS performances in the Channel, this analysis refines, with increased spatial and temporal resolutions, the characterization of near-surface SSC patterns revealing areas where concentrations are highly correlated with evolutions of tides and waves. Significant tidal modulations of near-surface concentrations are thus found in the eastern... |
| Tipo: Text |
Palavras-chave: Sediment transport; Numerical modeling; Satellite; ROMS; MERIS; MODIS. |
| Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00345/45607/45227.pdf |
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| Vic, Clement; Capet, Xavier; Roullet, Guillaume; Carton, Xavier; ,. |
| Despite its climatic and ecosystemic significance, the coastal upwelling that takes place off Oman is not well understood. A primitive-equation, regional model forced by climatological wind stress is used to investigate its dynamics and to compare it with the better-known Eastern Boundary Upwellings (EBUs). The solution compares favorably with existing observations, simulating well the seasonal cycles of thermal structure, surface circulation (mean and turbulent), and sea-surface temperature (SST). There is a 1.5-month lag between the maximum of the upwelling-favorable wind-stress-curl forcing and the oceanic response (minima in sea-surface height and SST), which we attribute to onshore-propagating Rossby waves. A southwestward-flowing undercurrent... |
| Tipo: Text |
Palavras-chave: Oman; Upwelling; Arabian sea; ROMS; Rossby waves; Eddy kinetic energy. |
| Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00382/49350/49752.pdf |
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