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| Ciani, Daniele; Carton, Xavier; Aguiar, A. C. Barbosa; Peliz, A.; Bashmachnikov, I.; Ienna, F.; Chapron, Bertrand; Santoleri, R.. |
| We study the surface signatures of Mediterranean water eddies (Meddies) in the context of a regional, primitive equations model simulation (using the Regional Oceanic Modeling System, ROMS). This model simulation was previously performed to study the mean characteristics and pathways of Meddies during their evolution in the Atlantic Ocean. The advantage of our approach is to take into account different physical mechanisms acting on the evolution of Meddies and their surface signature, having full information on the 3D distribution of all physical variables of interest. The evolution of around 90 long-lived Meddies (whose lifetimes exceeded one year) was investigated. In particular, their surface signature was determined in sea-surface height, temperature... |
| Tipo: Text |
Palavras-chave: Subsurface Anticyclones; Mediterranean water eddies; Satellite detection. |
| Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00405/51672/52220.pdf |
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| Bashmachnikov, I.; Neves, F.; Nascimento, A.; Medeiros, J.; Ambar, I.; Dias, J.; Carton, Xavier. |
| The present study defines new interpolation functions for hydrological data. These functions are applied to generate climatological maps of temperature-salinity distribution with a 25 m depth interval and a 30 km space interval (MEDTRANS data set). The data undergo rigorous initial data quality control, having passed several filtering procedures. The gridding is done on neutral density surfaces, which allows better representation of thermohaline fronts for the same gridding radius. The multi-pass Barnes optimum interpolation procedure with spatially variable size of the gridding window is used. The shape of the window accounts for the dominant along-isobath direction of water mass transport over steeply sloping topography. A local ratio of topographic to... |
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| Ano: 2015 |
URL: http://archimer.ifremer.fr/doc/00266/37729/35735.pdf |
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| Raj, R. P.; Halo, I.; Chatterjee, S.; Belonenko, T.; Bakhoday‐paskyabi, M.; Bashmachnikov, I.; Fedorov, A.; Xie, J.. |
| The interaction between the mesoscale eddies and the cyclonic gyre circulation of the Lofoten Basin is studied using a suite of satellite altimeters, a regional coupled ocean‐sea‐ice data assimilation system (the TOPAZ reanalysis) and Argo float data. An automated method identified 5,373/5,589 individual anticyclonic/cyclonic eddies in the Lofoten Basin from more than 65,000 altimeter‐based eddy observations, of which 70–85% are found to be nonlinear. The nonlinearity of eddies is estimated from its translational and rotational velocities. The study found clustering of highly intense nonlinear eddies on either side of the Lofoten Basin. Further, we show the distinct cyclonic drift of the anticyclonic and cyclonic eddies, both confined to the western side... |
| Tipo: Text |
Palavras-chave: Mesoscale eddies; Lofoten vortex; Lofoten basin; Gyre circulation; Altimetry; Argo floats. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00635/74707/74651.pdf |
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| Bashmachnikov, I.; Carton, Xavier. |
| Meddies, intra-thermocline eddies of Mediterranean water, can often be detected at the sea surface as positive sea-level anomalies. Here we study the surface signature of several meddies tracked with RAFOS floats and AVISO altimetry. While pushing its way through the water column, a meddy raises isopycnals above. As a consequence of potential vorticity conservation, negative relative vorticity is generated in the upper layer. During the initial period of meddy acceleration after meddy formation or after a stagnation stage, a cyclonic signal is also generated at the sea-surface, but mostly the anticyclonic surface signal follows the meddy. Based on geostrophy and potential vorticity balance, we present theoretical estimates of the intensity of the surface... |
| Tipo: Text |
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| Ano: 2012 |
URL: http://archimer.ifremer.fr/doc/00133/24424/22437.pdf |
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| Barbosa Aguiar, Ana; Peliz, A.; Neves, F.; Bashmachnikov, I.; Carton, Xavier. |
| We use cross-slope sections of direct current observations together with a high resolution numerical simulation to revisit estimates of transports and entrainment in the Gulf of Cadiz. We provide a three dimensional picture of the outflow from the Mediterranean into the intermediate layers of the Atlantic. In the model, the time-averaged Mediterranean Undercurrent is characterised by two cores of zonal velocity at 8°30′8°30′W: one at 500 m (in the σ1σ1 interval 31.6-31.831.6-31.8 kg m-3) and another around 1100 m (∼32.2∼32.2 kg m-3) with maximum westward velocity of 0.36 m s-1. A single well defined vein of saltier and warmer water (salinity maximum ∼36.9∼36.9 psu, 1 psu = 1 kg salt/1000 kg seawater) is found attached to the slope, centred at 1300 m... |
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| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00238/34908/33221.pdf |
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| Bashmachnikov, I.; Carton, Xavier; Belonenko, T. V.. |
| In this work, we obtain new results on the manifestation of meddies (or of other deep eddies) at the sea-surface, further developing the results by Bashmachnikov and Carton (2012). The quasi-geostrophic equations are used to describe a near-axisymmetric vortex in the upper ocean, forced at its lower boundary by the isopycnal elevation of a moving meddy. The solution thus obtained provides a better approximation of the characteristics of meddy surface signals. The results show that in subtropics large meddies with dynamic radius R-m >30 km are always seen at the sea-surface with AVISO altimetry, that medium-size meddies with R-m = 20 km may be seen at the sea-surface only if they are sufficiently shallow and strong, while small meddies with R-m =10 km... |
| Tipo: Text |
Palavras-chave: Meddies; Surface signal; Altimetry. |
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00245/35615/34134.pdf |
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