Data/hora: 17/06/2024 02:18:49

Provedor de dados: | 5
País: | France
Título: | Exploration multi-échelle de la circulation côtière dans le golfe de Gascogne
Autores: | Lazure, Pascal.
Data: | 2015-06-22
Ano: | 2015
Resumo: | The Bay of Biscay continental shelf is the site of a variety of physical processes, none of which are permanently dominant. The variability of the circulation from daily to interannual scales has been explored through both modelling and observation. Emphasis will be placed on one of the peculiarities of the Atlantic Plateau: the importance of river flows whose catchment areas represent half of the metropolitan territory. The mixing of these fresh waters with marine waters forms plumes that oscillate according to winds and general circulation. Increasingly refined modelling and a growing number of observations now make it possible to describe their fate and their extension as far as the English Channel. The general circulation on the shelf is weak and mainly under the influence of winds, as shown by two recent studies based on float trajectories and current measurements. However, some very energetic current structures have been described recently. These are the fall current, which occurs almost every year and carries water northward, and the even stronger Landes current, which occurs for a few days in the southern Gulf following a westerly gale. While most of my research focused on subtidal scales (time scale greater than one day), my perspectives are oriented towards the study of high-frequency hydrodynamics. These have been inspired by recent coastal observations made in different settings. Indeed, off the Croisic, internal oscillations of several metres in the thermocline have been measured at frequencies ranging from a few minutes to half an hour; along the Landes coast, an astonishing seasonality of tidal currents has been highlighted, since they decrease by a factor of three as soon as the summer stratification disappears. Moreover, in the bay of Miquelon, the bottom temperatures (between 30 and 60m deep) oscillate in summer by several degrees (up to 12°C) at an almost diurnal frequency (26h) while the tide is semi-diurnal. All these observations reveal the presence of internal waves down to very shallow depths and have, to date, never been the subject of specific studies along the French coasts, although their role on the mixing of water masses and coast-wide transport can be potentially very important. This theme is developed and the avenues for exploration through observation and modelling exposed.
Tipo: | Text
Idioma: | Francês

Identificador:

https://archimer.ifremer.fr/doc/00610/72176/70951.pdf

https://archimer.ifremer.fr/doc/00610/72176/

Formato: | application/pdf

Fonte:

info:eu-repo/semantics/openAccess

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