Circulation of the Caribbean Sea


  • Arnold L. Gordon


The geostrophic method was applied to six north-south hydrographic profiles across the Caribbean Sea and one across the Yucatan Strait. An axis of flow exists in the southern third of the Caribbean Sea. It flows directly over the steep slope in the reference layer found by Defant's method. This condition is similar to that of the Gulf Stream. The baroclinic mass distribution extends to approximately 1200 meters. Below this, the flow is weak (<5 cm/sec except in the depths of the Cayman and Yucatan basins, where currents of over 10 cm/sec occur. The deep and bottom flow may fluctuate in phase with overflow through the Windward and Anegada passageways. The main axis of flow corresponds closely with the main axis of spreading found by the core method in both the salinity maximum and the salinity minimum layers. The volume transport across the meridional section in the Caribbean is about 31 × 106 m³/sec toward the west. The northern passageways contribute only a small part of this water. The major outlet is the Yucatan Strait, where the calculated geostrophic volume transport corresponds to the transport through the Straits of Florida. The surface flow is directly affected by the wind. The upper baroclinic field of mass is produced by the Ekman transport of the light surface water toward the northern boundary. It is expected that divergences occur to the south of the main flow, and convergences occur to the north. This is supported by salinity and temperature sections. The upwelling in the south is calculated to be of the order of 10−4 cm /sec at the bottom of the Ekman layer.