陆架沙丘(波)活动量级和稳定性标志研究

Activity Level and Balance Signs of Subaqueous Dunes(Waves) in the Continental Shelf

陆架底流包含定时变向的潮流、定时定向的洋流和偶发性的暴风浪流,水下沙丘的塑造和运动是潮、浪动力共同作用的结果。用水文计算法计算沙丘迁移速率时应充分考虑陆架各动力要素的作用,并与定位观测速率相对照。按陆架水下沙丘的运动量级和发育过程可划分为强运动、弱运动、不运动(残留)和消亡(或埋藏)沙丘等4种类型,它们的稳定性标志,表现于海底状况、外部形态、粒度结构、水动力和迁移速率等方面。

Shelf bottom currents include multidirectional tidal currents, directional ocean currents and occa-sional storm waves, and subaqueous dunes are the integrated results of these tides and waves. Before using the hydrological method to calculate sand transportation speed, all the dynamical factors on the shelf are to be sufficiently considered, and the results should be compared with positioning observations. According to the activity level, subaqueous dunes（waves） can be divided into four patterns, including high activity dunes（ 〉 10 m/a）, low activity dunes（ 〈 10 m/a）, motionless（remnant） dunes and die out（imbedded） dunes. Their balance signs are manifested in seafloor status, dune forms, grain texture, hydrodynamics, migration speed etc.