Transports through the Straits of Florida

Abstract

Abstract Transports were calculated for four sections of the Florida Current from Key West to Jupiter, Florida, using a moored current-meter array and voltages from cross-channel telephone cables at the western and northern ends of the Straits of Florida. In addition, moored arrays were used to estimate transport through the Northwest Providence, Santaren, and Old Bahama Channels that connect the Florida Current to the southwestern part of the North Atlantic Ocean. Transport measurements were obtained for an 11-month period from December 1990 to November 1991. Mean transports of ∼25 Sv (1 Sv ≡ 106 m3 s−1) for the flow across the western ends of the straits, which agree quite well with recent estimates of 23.8 ± 1 Sv entering the Gulf of Mexico through the Yucatan Channel, were obtained from both the Key West to Havana cable and the moored array. This estimate is about 5 Sv less than the generally accepted transport through the northern end of the straits at 27°N. This difference was partially accounted for by inflows through the side channels with more transport from the Old Bahama than the Northwest Providence Channel. The variability in the southern part of the straits was larger than at 27°N and included large diversions of the Florida Current south of the Cay Sal Bank and into the Santaren Channel that were caused by large meanders of the flow. The variability of transport in the side channels contributed to the variability of the Florida Current and reduces the correlations of the transports at the ends of the straits. Therefore, the well-measured transport at 27°N is not an accurate indicator of the transport of the Loop Current out of the Gulf of Mexico.