동중국해 양자강희석수의 염분과 클로로필 증가에 대한 아표층수 역할

Abstract

To examine the contribution of subsurface water to salinity increase and nutrient enrichment in the Changjiang Diluted Water, East China Sea, satellite-tracked surface drifting buoy data were analyzed. In the summer 2007 observation period, salinity increased abruptly in association with a temperature decrease, and corresponded with the passage of a tropical depression. A significant part of the salinity increase is explained by upward advection of deeper saline water, generated by surface divergence resulting from cyclonic winds. Surface water divergence was calculated from drifter movement and compared with Ekman transport estimation. Vertical velocities estimated from both methods were similar during the tropical depression, and vertical advection could explain the abrupt salinity increase. Satellite chlorophyll observations suggested an increase in phytoplankton after the passage of the tropical depression, indicating that subsurface upwelling is also delivering nutrients to the surface layers.