琉球群岛以东的西边界流与东海黑潮流量时空特征的研究

通过最新的高分辨率再分析海洋数据资料,对于东海黑潮以及琉球群岛以东海域的海流进行了研究。结果表明琉球群岛以东西边界流最大流速出现在600~1200 m深度的地形坡度最大处,大小约为0.2 m/s。由于冲绳岛以南庆良间水道的水交换对于东海黑潮流量有重要的影响,东海黑潮的平均流量从南向北逐渐递增,平均流量为28×106~35×106m3/s;琉球群岛以东的西边界流流量则比东海黑潮小一个量级,平均值小于其变化的方差;由于受庆良间水道海流的影响,冲绳岛东侧的流量要远小于奄美大岛东侧的流量。同一纬度大洋中西传的Rossby波对琉球群岛以东的西边界流有较大影响,因此琉球群岛以东西边界流的流量有大约100 d的显著变化周期。庆良间水道以南的东海黑潮由于主要受台湾以东黑潮流量的控制,也有大约100 d的显著变化周期,庆良间水道以北的东海黑潮则没有该特征。

The study of the temporal and spatial characteristics of western boundary current East of Ruykyu submarne ridge and the transport of Kuroshio in East China Sea

Kuroshio in the East China Sea(KECS) and the currents in the east of the Ryukyu Islands are investigated by analyzing the up-to-date reanalysisdataof the high resolution ocean model.It is found that there is a western boundary current in the east of Ryukyu Islands with a maximum core velocity of 0.2 m/s at 600~1 200 m over the shelf slop.Because the water exchange through the ocean trough in the southwest of Okinaw a Island can affect the transport of KECS, the mean transport of KECS steadily increases from south to north, which is 28×10⁶~35×10⁶m³/s; the transport of the western bo undary current in the east of Ryukyu Islands is less an order of magnitudethan that of KECS, whose mean value is less than the standard deviation; because of the current through the ocean trough in the southwest of Okinawa, the transport in the east of Okinawa is less than that in the east of Amami-ohshima.The Rossby wave propagating westward in the east of Ryukyu Islands could influence the western boundary current in the east of Ryukyu Islands distinctly, so the distinct period of the transport of the west ern boundary current in east of Ryukyu Islands is approximately 100 d.The KECS in the south of the ocean trough is mainly controlledby the Kuroshio in the east of Taiwan, so the period of its transport is also approximately 100 d.But the KESC in the north of the ocean trough does not have thisfeature.