Interaction of Mediterranean water eddies with Sedlo and Seine Seamounts, Subtropical Northeast Atlantic

Abstract

During years 2003 and 2004 both Sedlo and Seine Seamounts, lying in the area of influence of the Mediterranean water outflow in the Northeast Atlantic, were investigated in the framework of the EU-funded project OASIS. Analysis of CTD data shows that the levels of major variability in temperature and salinity were confined to the upper ocean layer, which is subject to seasonal air–sea heat exchange, and to the Mediterranean Water (MW) level. In this paper we concentrate on the latter case and show that the variability observed resulted from Mediterranean water eddies (Meddies) colliding with the seamounts. Combined data from CTD surveys, current meter moorings, ship-mounted ADCP and satellite altimetry suggest that during the period of observations there was only one Meddy interacting with each of the seamounts. On Sedlo Seamount intensive interaction resulted in the loss by the Meddy of about 25% of the salt around the seamount, whereas on Seine the Meddy (or portion of it) escaped the seamount after performing several rotations around the summit without any significant interaction.