Baseline study of ocean dynamics in support of Repsol exploration driling project off the south coast of Portugal, Apr-July 2014

Abstract

A base study of the ocean dynamics was conduced for Repsol Exploration, S.A. in support of an Exploratory Drilling Project off the south coast of Portugal. From April to July 2014, current observations covered the whole water column at the transition from the Diogo Cão Trench to the Bartolomeu Dias Plateau, with emphasis on the surface 80 m and the bottom 250 m. Mediterranean Water flow reaching the Plateau from the Trench dominated the dynamics, with two current cores at 80 and 140 m above the bottom, with 30 cm/s average speed and maxima above 40 cm/s. A counterclokwise turn of the current as it flew towards W, after leaving the Trench, suggests bathymetric adjustment. A tendency for current strengthning was observed along the observational period, 5-day oscillations with 10 cm/s amplitude superimposed, at counterclockwise angle of 20-30º, the mean current vector. Clockwise polarized inertial oscillations appeared ubiquitous in both the surface and the bottom layers, overriding the tidal currents, with amplitudes up to 10 cm/s