Effects of the Pearl River plume on the vertical structure of coastal currents in the Northern South China Sea during summer 2008
Effects of the Pearl River plume on the vertical structure of coastal currents in the Northern South China Sea during summer 2008
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DOI：
10.1007/s10236-014-0779-5
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发表时间：
2014-10
期刊：
影响因子：
2.3
通讯作者：
Y. Shu;Ju Chen;Jinglong Yao;Jiayi Pan;Weiwen Wang;H. Mao;Dongxiao Wang
中科院分区：
文献类型：
--
作者：
Y. Shu;Ju Chen;Jinglong Yao;Jiayi Pan;Weiwen Wang;H. Mao;Dongxiao Wang
南海沿岸海洋过程试验（SCOPE-PP）的锚定海流计资料分析表明，珠江羽流（PRP）与沿岸急流的相互作用导致了北方南海沿岸流垂直结构的强烈空间变化。观测结果表明，NSCS沿岸流总体上是向东的，将PRP水向东传播。位于含盐沿海水域顶部的较轻的微咸羽流加强了表面附近的分层，并阻止了向下的动量输送，导致系泊地点S205处的速度出现强烈的垂直切变。与此同时，羽流水使海平面上升。由于越岸方向的地转平衡，上层东向沿岸流在近岸（S205附近）加强，在离岸（S206和S305附近）减弱，这是由于羽状水的侵入。因此，速度的垂直切变在S205处增强，而在S206和S305处减小。此外，由于羽流随风变化很大，S205和S206之间响应于风的速度垂直切变是不同的。2008年夏季的数值模拟结果证实，PRP通过增加（减少）上层海流约0.2 m s-1和轻微减少（增加）中层海流，增强（减弱）了向岸（离岸）侧流速的垂直切变。
Analyses of moored current meter data from the South China Sea (SCS) Coastal Oceanographic Process Experiment Pilot Project (SCOPE-PP) reveal that strong spatial variation in the vertical structure of coastal currents in the northern SCS (NSCS) was caused by the interaction between the Pearl River plume (PRP) and the alongshore coastal jet. Observations indicate that the NSCS coastal current was generally eastward, spreading the PRP water eastward. The lighter brackish plume residing on the top of the saline, coastal water strengthened the stratification near the surface and blocked the downward momentum transport, resulting in a strong vertical shear of the velocity at the mooring site S205. Meanwhile, the plume water raised the sea level. Because of the geostrophic balance in the across-shore direction, the eastward coastal current in the upper layer strengthened on the onshore side (near S205) and weakened on the offshore side (near S206 and S305) due to the plume water intrusion. Therefore, the vertical shear of the velocity was enhanced at S205 and reduced at S206 and S305. Moreover, because the plume varied substantially with the wind, the vertical shear of the velocity responding to the wind was different between S205 and S206. The numerical simulation during summer 2008 confirms that the PRP enhances (weakens) the vertical shear of the velocity on the onshore (offshore) side by increasing (decreasing) the upper-layer current by about 0.2 m s-1and decreasing (increasing) the middle-layer current slightly.