Interannual evolutions of (sub)mesoscale dynamics in the Bay of Biscay and the English Channel
Guillaume Charria1, Frédéric Vandermeirsch1, Sébastien Theetten1, Özge Yelekçi2, Charefeddine Assassi1 and Nicole J Audiffren3, (1)IFREMER, Plouzané, France, (2)IFREMER, DYNECO - Laboratoire de Physique Hydrodynamique et Sédimentaire, Plouzané, France, (3)Centre Informatique National de l'Enseignement Supérieur
Abstract:
In a context of global change, ocean regions as the Bay of the Biscay and the English Channel represent key domains to estimate the local impact on the coasts of interannual evolutions. Indeed, the coastal (considering in this project regions above the continental shelf) and regional (including the continental slope and the abyssal plain) environments are sensitive to the long-term fluctuations driven by the open ocean, the atmosphere and the watersheds. These evolutions can have impacts on the whole ecosystem. To understand and, by extension, forecast evolutions of these ecosystems, we need to go further in the description and the analysis of the past interannual variability over decadal to pluri-decadal periods.
This variability can be described at different spatial scales from small (< 1 km) to basin scales (> 100 km). With a focus on smaller scales, the modelled dynamics, using a Coastal Circulation Model on national computing resources (GENCI/CINES), is discussed from interannual simulations (10 to 53 years) with different spatial (4 km to 1 km) and vertical (40 to 100 sigma levels) resolutions compared with available in situ observations.
Exploring vorticity and kinetic energy based diagnostics; dynamical patterns are described including the vertical distribution of the mesoscale activity. Despite the lack of deep and spatially distributed observations, present numerical experiments draw a first picture of the 3D mesoscale distribution and its evolution at interannual time scales.
