Abstract
The time series of the vertical profile of the coastal current at every 2 m were observed at the Sendai-Wan for 15 days using the Acoustic Doppler Current Profiler set on the sea bottom (B-ADCP). The currents in layers from surface to 8 m corresponds well with the wind, but their speeds become weaker rapidly as going to the deeper layers. Notably, in the mid depth and bottom layers, distinctive periodic fluctuations of the current were found in the diurnal band. Applying the simple fourier analysis to the time series of each layer, these fluctuations are recognized as the combination of the two internal oscillations having the near inertial periods, 21.2 and 18.0 hours, which are located in both sides of the inertial oscillation (19.4 hours). These oscillations are concentrated under the thermocline.
These results could not be obtained without the B-ADCP. Then, we intend to utilize the B-ADCP to make clear the characteristics of the coastal current in the various seas.
