Observations of thermal variations in the mixed layer depth of the equatorial Atlantic

A set of Argo temperature data collected in the equatorial Atlantic [0°-5°N, 55°W-10°E] was used to estimate the mixed layer depth (MLD) and associated thermal variability for the period between January 2002 to April 2009. MLD climatology were estimated from 0.3°*0.3° median binned temperature profile using temperature difference criterion with a reference layer at 10m depth. At the 30m depth, 22°C cold water flows from the south onto the continental shelfs of Ghana-Cote D´Ivoire indicating the potential source of nutrient rich bottom water that nourishes the MLD and drives biological production. The MLD was shallow at the east and relatively deeper at the western end of the equatorial Atlantic. Variability within the MLD can be associated with variations in the westward flow of the warm and saline Equatorial Undercurrent. Further warming of the equatorial Atlantic has a potential of increasing the mixed layer depth and affecting upper surface ocean processes.