Water Circulation in the Beagle Channel, a modeling study

MARTÍN, J.; CUCCO, A.; FERNÁNDEZ, D.; QUATTROCCHI, G.

Congreso; EGU General Assembly 2019; 2019

The Beagle Channel is a strait in the ?Tierra del Fuego? on the extreme southern tip of South America. Thisnarrow and long channel is one of the three navigable passages connecting the Pacific and Atlantic Oceansand it is shared between Chile and Argentina. Within the framework of the ERANET Lac Project CLIMAR(http://climar.cnr.it/index.php/contact/) a modeling study was conducted to investigate the water circulation insidethis Channel and in the surrounding areas in order to evaluate the effects of atmospheric forcing on the channelfluxes and main hydrodynamics. A high-resolution 3D hydrodynamic model based on the finite elements methodwas implemented to an extended domain covering the whole Patagonian Shelf, part of the Drake Channel and partof the South-Eastern Pacific Ocean. The model horizontal spatial resolution was varying between several km foropen oceans up to 100 m for Ushuaya Bay inside the Channel. A full year simulation run was carried out to reproducethe circulation inside the channel as generated by tides, atmospheric and thermohaline forcing. Atmosphericand oceanographic model forcing were obtained from available operational prediction systems for the year 2016.Nudging procedures were adopted to reproduce the effects of outer circulation patterns on the channel main hydrodynamics.Tidal dynamics were reproduced in details in the whole area, with a good accuracy inside the channelestablished by comparing observed and computed diurnal and semidiurnal harmonics. The model results were alsocompared with data on water currents, salinity and temperature fields available for the eastern side of the channel.Numerical simulations were performed to investigate the seasonal variability of the water fluxes, residual circulationand water residence times inside the channel. The obtained results provide a preliminary overview of theBeagle Channel general circulation, which is an essential step to understand the effects of the climatic variabilityon the local hydrodynamics.