Mixing in the Deep Waters of the Western Mediterranean

In terms of the overall mixing environment, the Mediterranean Sea has relatively small tides and relatively weak winds compared with the greater ocean environment, so vertical diffusion due to mechanical mixing is likely to be generally smaller than in the open ocean. As the western Mediterranean deep water (WMDW) is naturally fresher and colder than the Levantine intermediate water (LIW), salinity and temperature both decrease downward below the LIW core toward the deep water. In the halocline-thermocline between the core of LIW and the deep water, warmer saltier waters overlie colder fresher waters and in such a region salt finger mixing processes can be effective mixing agents transporting salt, heat, and density downward. For the deep western Mediterranean, vertical diffusion due to mechanical mixing is expected to be small; and downward mixing of heat salt and density is expected to be substantial in the halocline-thermocline 400-1500-m depth.