Transport of Antarctic bottom water through the Kane Gap, tropical NE Atlantic Ocean

摘要

We study low-frequency properties of the Antarctic Bottom Water (AABW) flowthrough the Kane Gap (9° N) in the Atlantic Ocean. The measurementsin the Kane Gap include five visits with CTD (Conductivity-Temperature-Depth) sections in 2009–2012 and ayear-long record of currents on a mooring using three AquaDoppcurrent meters. We found an alternating regime of flow, which changesdirection several times during a year. The seasonal signal seems to dominate.The maximum daily average values of southerly velocities reach0.20 m s?1, while the greatest north-northwesterly velocity is as highas 0.15 m s?1. The velocity and transport at the bottom are alignedalong the slope of a local hill near the southwestern side of the gap. Thedistribution of velocity directions at the upper boundary of AABW is wider.The transport of AABW (Θ < 1.9 °C) based on the mooringand LADCP (Lowered Acoustic Doppler Current Profiler) data varies approximately within ±0.35 Sv in the northern andsouthern directions. The annual mean AABW transport through the Kane Gap isalmost zero.