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| Qiu, Bo; Chen, Shuiming; Klein, Patrice; Sasaki, Hideharu; Sasai, Yoshikazu. |
| Located at the center of the western North Pacific Subtropical Gyre, the Subtropical Countercurrent (STCC) is not only abundant in mesoscale eddies, but also exhibits prominent submesoscale eddy features. Output from a 1/30 degrees high-resolution OGCM simulation and a gridded satellite altimetry product are analyzed to contrast the seasonal STCC variability in the mesoscale versus submesoscale ranges. Resolving the eddy scales of >150 km, the altimetry product reveals that the STCC eddy kinetic energy and rms vorticity have a seasonal maximum in May and April, respectively, a weak positive vorticity skewness without seasonal dependence, and an inverse (forward) kinetic energy cascade for wavelengths larger (shorter) than 250 km. In contrast, the... |
| Tipo: Text |
Palavras-chave: Circulation/ Dynamics; Eddies; Instability; Mesoscale processes; Observational techniques and algorithms; Altimetry; Models and modeling; Ocean models; Variability; Seasonal variability. |
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00245/35588/34142.pdf |
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| Qiu, Bo; Chen, Shuiming; Klein, Patrice; Ubelmann, Clement; Fu, Lee-lueng; Sasaki, Hideharu. |
| Utilizing the framework of effective surface quasi-geostrophic (eSQG) theory, we explored the potential of reconstructing the 3D upper ocean circulation structures, including the balanced vertical velocity (w) field, from high-resolution sea surface height (SSH) data of the planned SWOT satellite mission. Specifically, we utilized the 1/30°, submesoscale-resolving, OFES model output and subjected it through the SWOT simulator that generates the along-swath SSH data with expected measurement errors. Focusing on the Kuroshio Extension region in the North Pacific where regional Rossby numbers range from 0.22 to 0.32, we found that the eSQG dynamics constitutes an effective framework for reconstructing the 3D upper ocean circulation field. Using the modeled... |
| Tipo: Text |
Palavras-chave: Variability; Models and modeling; General circulation models; Vertical motion; Circulation/ Dynamics; Quasigeostrophic models; Mesoscale processes; Observational techniques and algorithms; Oceanic variability; Altimetry. |
| Ano: 2016 |
URL: https://archimer.ifremer.fr/doc/00309/42032/41331.pdf |
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| Barbosa Aguiar, A. C.; Menesguen, Claire; Le Gentil, Sylvie; Schopp, Richard; Carton, Xavier. |
| Nearly all the subsurface eddies detected in seismic imaging of sections in the northeast Atlantic have been assumed to be anticyclones containing Mediterranean Water (MW). Fewer MW cyclones have been observed and studied. In this study, the work of previous numerical studies is extended to investigate some characteristics of layering surrounding MW cyclones, using a primitive equation model with equal diffusivities for salinity and temperature to suppress the effects of double diffusion. It is shown that, after a stable state is reached, both anticyclones and cyclones display similar patterns of layering: stacked thin layers of high acoustic reflectivity located above and below the core of each vortex, which do not match isopycnals. The authors conclude... |
| Tipo: Text |
Palavras-chave: Geographic location/entity; North Atlantic Ocean; Circulation/ Dynamics; Small scale processes; Atm/Ocean Structure/ Phenomena; Eddies; Vortices; Observational techniques and algorithms; Acoustic measurements/effects; Models and modeling; Primitive equations model. |
| Ano: 2015 |
URL: http://archimer.ifremer.fr/doc/00281/39190/37746.pdf |
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| Leckler, Fabien; Ardhuin, Fabrice; Peureux, Charles; Benetazzo, Alvise; Bergamasco, Filippo; Dulov, Vladimir. |
| The energy level and its directional distribution are key observations for understanding the energy balance in the wind-wave spectrum between wind-wave generation, nonlinear interactions, and dissipation. Here, properties of gravity waves are investigated from a fixed platform in the Black Sea, equipped with a stereo video system that resolves waves with frequency f up to 1.4 Hz and wavelengths from 0.6 to 11 m. One representative record is analyzed, corresponding to young wind waves with a peak frequency fp = 0.33 Hz and a wind speed of 13 m s−1. These measurements allow for a separation of the linear waves from the bound second-order harmonics. These harmonics are negligible for frequencies f up to 3 times fp but account for most of the energy at higher... |
| Tipo: Text |
Palavras-chave: Circulation; Dynamics; Waves; Oceanic; Observational techniques and algorithms; Remote sensing. |
| Ano: 2015 |
URL: http://archimer.ifremer.fr/doc/00284/39524/38017.pdf |
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