동중국해 북부해역에서의 해저 부근 혼합

Abstract

Shipboard ADCP, CTD and MSP (microstructure profiler) observations were made in the continental shelf in the East China Sea in August 2005 and August 2006. The data sets reveal variable bottom mixed layer heights with 5 ~ 15 m. Near the bottom, the turbulent kinetic energy dissipation rates are high with typically O(10-7 Wkg-1) but occasionally close to 10-6 Wkg-1 and corresponding vertical eddy diffusivities reach to 10-2 m2s-1. High values of dissipation rate and vertical diffusivity are consistent with high turbidity especially in the shallow region. The data from repeated MSP castings and vessel mounted ADCP observations for 5 hours in 2005 and 25 hours in 2006 show that episodic intrusions of enhanced near-bottom turbulence into the upper layers of water column. Good correlation between the height of bottom mixed layer and the phase of tidal current indicates near-bottom mixing in the region occurs mainly due to the tidal stirring.