Modeling the Impacts of the Loop Current on Circulation and Water Properties in Pulley Ridge Area, Southwest Florida Shelf

A high resolution (~1.5km) regional ocean model has been developed for the southern Florida Shelf and Florida Straits. Analysis of the model shows that the meandering of the Gulf of Mexico Loop Current exerts strong impacts on the circulation dynamics over the Pulley Ridge region on the southwestern Florida shelf, where the Loop Current (LC) turns east into Florida Straits to become Florida Current (FC). In particular, the northward migration of the LC/FC front tends to drive a strong onshelf (eastward) transport of the gulf water onto the southern Pulley Ridge, an important area where abundant photosynthetic corals can be found at depth between 60 and 90 m. Remotely or locally generated eddies over the western shelf slope of the Pulley Ridge can also be blocked by the northern LC/FC front when it is closely in contact with the shelf break. These eddies drive strong upwelling of slope water toward the shelf break and sometimes onto the shelf. In the southern Florida Straits, FC may also strongly interact with the shelf slope from the Dry Tortugas to the Florida Keys, often in association with the meandering of the Florida Current. Moreover, a significant return flow, largely within the upper 150 m, may be produced when the FC impinges upon the continental slope. The return flow may extend all the way from the contact point between the FC and shelf slope to the northwestern side of the Pulley Ridge, providing yet another mechanism for water exchange between the shelf and slope.