南海季风实验(SCSMEX)期间,由台湾大学在南海中部深海盆投放了3个定点ATLAS浮标,用来观测长时间序列的水温、海流和气象数据。利用调和分析和EOF方法对1998年10月至1999年4月3个站点近6个月的流速观测资料进行分析,研究了观测海区的潮流空间结构特征。调和分析结果表明,该海区以全日潮流为主,潮流椭圆随深度旋转,且潮流以顺时针旋转为主,潮流振幅存在显著的垂向变化。对实测海流进行10-30 h的带通滤波保留潮周期部分,滤波后的潮流进行EOF分解得到潮流存在不同的垂向模态,证明南海深水海盆潮流具有较强的斜压性。
During the South China Sea monsoon experiment,Taiwan University put three moored ATLAS buoys in the center deep basin of the South China Sea,in order to observe the long time serial data of water temperature,current and climate.Using almost 6 months current observation of three stations which is from October of 1998 to April of 1999,we used harmonic analysis and EOF method to study the spacial structure characteristic of tidal current in the observed sea.The results of harmonic analysis show that,in the observed sea it is dominated by the diurnal tide,the tidal ellipses rotate through the entire water column,and the tidal current is dominated by clockwise rotation,there are marked vertical variation in the tidal amplitudes.Making band-pass filtering of 10~30 hours on the real observed current and keeping the tidal period,after that using EOF to analyze the filtered tidal current,we can find that there are different vertical modes in the tidal current,which indicates that the tidal current in the deep basin of the South China Sea has strong baroclinicity.