Observational characteristics and dynamic mechanism of low-salinity water lens for the offshore detachment of the Changjiang River diluted water in August 2006

• 作者: Zhenyu Liu Wenjing Zhang Xuejun Xiong Shouxian Zhu
• 来源期刊: 海洋学报（英文版）
• 年，卷（期）: 2021,（3）
• 所属期刊栏目: Physical Oceanography, Marine Meteorology and Marine Physics
• 页码范围: 34-45
• 页数: 12页
• 语种: 英文

摘要

The Changjiang River diluted water (CDW) spreads into the East China Sea (ECS) primarily in a plume pattern,although in some years, low-salinity water lenses (LSWLs) detach from the main body of the CDW. In-situ observations indicate that in August 2006, a LSWL detached from the main body of the CDW near the river mouth. In this paper, the effects of winds, tides, baroclinity and upwelling on LSWLs are explored with a three-dimensional model. The results show that: (1) winds play a crucial role in these detachment events because wind-induced northerly Eulerian residual currents impose an uneven force on the CDW and cut it off, thus forming a LSWL; (2) upwelling carries high-salinity water from the lower layer to the upper layer, truncating the low-salinity water tongue vertically, which is conducive to the detachment and maintenance of LSWLs; and (3) upwelling during the evolution of a LSWL is caused by the combined effects of winds and tides. The influences of wind-induced upwelling are mainly near the shore, whereas the upwelling along the 30 m isobath is predominantly affected by tides, with the effect increasing from neap tide to spring tide.