Observation of convergence, divergence and sinking velocity at a thermohaline front in the Kii Channel, Japan

Detailed flow structure around a thermohaline front in the Kii Channel, Japan, was observed for the first time with the use of an 130 kHz Acoustic Doppler Current Profiler (ADCP). Surface water converged with counter-clockwise motion at the interface between cold coastal water and warm offshore water. After sinking, these waters diverged with a clockwise motion, forming skirt-like distributions in the lower layer below the front. The maximum surface convergence and sinking velocity were 2.0 x 10−4 s−1 and 0.25 cm s−1, respectively. These observations and our results substantiate previous numerical studies.