Low frequency current variability on the shelf break northeast of Taiwan
Low frequency current variability on the shelf break northeast of Taiwan
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DOI：
10.1007/bf02237288
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发表时间：
1993-03
影响因子：
2.3
通讯作者：
T. Tang;Y. Yang
中科院分区：
文献类型：
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作者：
T. Tang;Y. Yang
一台安装在浮标上的声学多普勒海流剖面仪被部署在台湾东北海岸外的陆架断裂处，以监测上层海洋的海流变化。获取的资料表明，上层水柱的水流最初是西南的，然后突然转向西北。这种突变发生在10月中旬，从表层开始，然后逐渐延伸到更深的层。与此相反，在整个记录期间，低水柱中的气流是西南的，但其幅度在10月中旬之后减弱。海流由西南向西北的突变与黑潮的入侵有关。对两个CTD铸模的检查表明，10月中旬方向转移后，上层海洋的盐度有所增加，进一步表明黑潮入侵。基隆的海平面数据为黑潮的入侵提供了其他证据。海平面随着入侵的发生而下降，并一直保持在较低的值，直到记录结束。西北流把水从台湾北部海岸带走，是造成这次下降的原因。尽管黑潮的入侵主要局限于上层海洋，但它确实对整个水柱产生了影响。对彭家峪风场记录的分析表明，黑潮入侵的时间与东北季风增强的时间不一致。局地风和20米处的海流不一致。黑潮潮流的变化和黑潮路径的起伏都可能是造成局部流变化的原因。由于黑潮的入侵与局地风的变化关系较弱，因此可能是由非局地因素引起的。
A buoy-mounted Acoustic Doppler Current Profiler was deployed on the shelf break off the northeast coast of Taiwan to monitor current variations in the upper ocean. The acquired data show that the flow in the upper water column was initially southwest and then abruptly turned northwest. This abrupt change occurred in mid-October, starting from the surface layer and then gradually extending to the deeper layer. In contrast with this flow, the flow in the lower water column was southwest over the entire record, but its amplitude was reduced after the middle of October. The abrupt change of current from southwest to northwest is related to the intrusion of Kuroshio. Examination of two CTD casts showed the salinity of the upper ocean to have increased after the directional shift in mid-October, further indicating the Kuroshio intrusion. The sea level data at Keelung provided other evidence for the intrusion of Kuroshio. The sea level descended as the intrusion occurred and kept the low value until the end of the record. The northwest flow, which carried the water away from the northern coast of Taiwan, is responsible for this descent. Although the intrusion of Kuroshio was mainly confined to the upper ocean, it did have influence on the whole water column. Examination of the wind record at Pengchiayu showed that the time of Kuroshio intrusion was not coincident with the intensification of the northeasterly monsoon. The local wind and the current at 20 m were incoherent. Both the variation of Kuroshio current and the fluctuation of Kuroshio path may be responsible for the variation of the local current. Since the intrusion of Kuroshio has a weak relationship with local wind variation, it appears to be induced by non-local factors.