1997年7月至1999年10月, 在位于热带东太平洋的中国多金属结核开辟区的东、西区各布放了一套深海锚系, 对离底600 m(mab)以内的近底层流动进行观测. 对低通滤波后的流速数据进行的统计分析结果表明, 开辟区近底层低频流动的时间尺度为25~120天, 其中周期为51天左右的波动是低频振动的主要成分; 地形对离底50 m以内的低频流动有明显的影响; 底层强化的剪切平流对低频波动的调制作用是产生层低流动垂向频移的动力机制. From July 1997 to October 1999, a set of deep-sea anchors were deployed in the eastern and western parts of the China polymetallic nodule development zone in the tropical eastern Pacific to conduct near-bottom flow within 600 m (mab) from the bottom The results of the statistical analysis of the low-pass filtered flow velocity data show that the time scale of low-frequency flow near the bottom is 25 ~ 120 days, of which the fluctuation of about 51 days is the main component of low-frequency vibration. The low-frequency flow within 50 m of the bottom has a significant effect. The modulation effect of the enhanced shear advection on the low-frequency fluctuations is the dynamic mechanism of vertical frequency shift of the low-level flow.