Variability in the Gulf Stream recirculation gyre

Using historical hydrographic data, a salinity front which marks the eastern edge of the Gulf Stream recirculation on the 10°C isotherm surface is tracked. In the region between 25° and 35°N the longitudinal position of the front exhibits considerable seasonal variability not previously detected at this depth. During January and the summer months the edge of the recirculation is at 76°W, while in spring and late autumn the front moves east to 65°W. The change in the longitudinal position of the recirculation front coincides with a meridional displacement of the Gulf Stream path. When the front is in its easternmost position, the Gulf Stream is to the south, while when the front moves to the west, the Gulf Stream shifts north. It is possible that the recirculation reacts to the meridional displacement of the Gulf Stream maintaining the volume within the recirculation constant.