西沙岛礁泻湖潮流特征分析

Characters of Tide and Current in a Lagoon of the Xisha

基于两年实测数据,本文对西沙海域某泻湖的内潮和分层流进行了分析。结果表明,该海域主要分潮为K1、O1和M2分潮。对于分层流,SSA分潮的影响应值得注意。对余潮和余流的分析表明余潮和余流主要分布在低频区,且该时间段内台风和冷空气的影响没有引起明显的水位变化。潮流向玫瑰图表明潮流方向受地形影响,以沿岸反复流为主;而余流则以单向流为主,且会随着水深而顺时针或逆时针变化。余流的EOF分析表明泻湖内不同测点东向流和北向流的主模态都相同。

Based on the measurement data of two years,characteristics of tide and currents in a lagoon in the Xisha are discussed in this paper.The results show that the main tidal components are K1,O1 and M2.For currents below the free-surface,the influence of the SSA tide should not be neglected.The analysis of residual tide and residual current shows that they are mainly distributed in the low frequency region,but impacts of typhoon and cold air are not evidenced.Studies on the direction of the current show that the alongshore reversing current dominants the current induced by the astronomic tide.For residue currents,their direction is nearly fixed,but will be varied along the depth.The EOF analysis shows that the vertical structures of the eastward velocities and the northward velocities are similar with each other.