关键词: 流场, 夏季, 沿程变化, 浙江近海

Abstract: To research the current character, variation and pattern in vertical profile, current speed and direction were observed using ADCP at 3 fixed sites along the Zhejiang offshore in summer of 2006 and 2009. The results showed that: (1) In central and north of Zhejiang offshore (A and B sites), the current was rotating flow and it rotated in clockwise direction. In the south area(C site), the flood tidal current was north,while it was north by east in ebb period. In vertical profile, the current direction was unanimous. (2) The vertical average speed was similar in the three observation sites (44.4~51.1 cm/s), but significant difference presented in average speed of vertical profile. The biggest speeds in the three sites were all bigger than 110 cm/s, which all occurred in the flood period in spring tide. (3) During observation period, the average residual flow speed at A, B and C site was 21.9, 12.3 and 22.3 cm/s, respectively. Influenced by the Yangtze diluted water, at A and B sites the residual current directions in the upper layers were southwest. From the middle to the bottom layers the residual currents were veering in counter clockwise direction with the southeast direction in lower layers, which may be caused by the Taiwan Warm Current traction. At C site residual current flow was more consistent in vertical, which was mainly affected by the northeast monsoon.(4)In summer, along the Zhejiang offshore from south to north, the current direction turned to east gradually at central area (between B and C site).(5)During the low water discharge of Yangtze, the south costal current existed in the central and north of Zhejiang offshore. The current adjacent to Zhejiang was controlling by monsoon, the Yangtze diluted water and the Taiwan Warm Current together, but the role of them varied significant spatially.

Key words: current, summer, spatial variability, Zhejiang offshore