南海北部大陆坡区的突发性强流

ABRUPT STRONG CURRENTS OVER CONTINENTAL SLOPE OF NORTHERN SOUTH CHINA SEA

应用声学多普勒流速剖面仪的定点观测资料 ,分析南海北部东沙群岛西南大陆坡区孤立内波引起的突发性强流。本次观测到的这些强流主要特征为 :( 1 )在 0— 1 50m的观测深度层内 ,流向主要以向岸方向为主 ,每一峰值持续时间约为 1 0— 2 5min。 ( 2 )在大潮期间 ,强流事件出现的次数较多 ,且强度大 ;在小潮期则反之。 ( 3)最强的突发性海流发生于斜压内潮强盛期 ,比天文大潮落后 4— 5d。 ( 4 )突发性强流事件既可呈现多峰型 ,也可呈单峰型。

The current data observed with Acoustic Doppler Current Profiler (ADCP) at two fixed stations were used to analyze the abrupt strong currents due to internal solitons over the continental slope to the west and southwest of Dongsha Islands in the northern South China Sea.The major features of abrupt strong currents are as follows. (1) In the layer of 0—150m,strong currents in the shoreward direction (near NW) dominate.The maintaining time of every velocity peak during a strong current event is between 10 and 25 minutes. (2) During the period of spring tide,there occur more strong current events;During the period of neap tide,the case is reversed. (3) The strongest abrupt current appears when the internal tide has the largest amplitude,which is 4 or 5 days later than the occurrence of spring tide. (4) Abrupt strong current events occur either with multiple velocity peaks or with a single peak.