A deep stepped thermohaline structure deep in the Mediterranean

Abstract

A deep stepped thermohaline structure has been observed in the Tyrrhenian Sea below the Levant ine water salinity maximum. The layers are remarkably homogeneous starting with a thickness of 10 m - 20 m at 600 m and thereafter increasing dramatically to 200 m thickness at 1200 m depth. The thickness of the interfaces between the layers is a few metres or less with typical changes of O.OSoC - 1°C and -0.02%,0 for 'temperature and salinity ' respectively decreasing with depth. The identity of the layers is sustained over a horizontal distance of at least 7S n.mi and at a point for a time interval of more than a year. Stepped structure is also reported in the Sardinian Channel, however, the steps are less regular and the maximum thickness of the layers is about 40 m. The layers are not continuous from one station to the next which indicates that horizontal coherence is less than 10 n.mi - IS n.mi .