辐射沙脊群海域深槽摩阻流速特性研究

基于夏冬两季南黄海辐射沙脊群海域实测流速垂向分布资料,利用卡曼-普朗特公式估算深槽摩阻流速并分析了该海域摩阻流速分布特征,并提出摩阻流速快速估算方法。结果表明,辐射沙脊群海域涨落急时刻流速垂向分布较符合卡曼-普朗特对数流速分布。夏季平均摩阻流速为7.4cm/s,呈现北大南小、近岸大远岸小的格局;冬季平均摩阻流速为6.0cm/s,呈现中部大南北小、近岸大远岸小的格局。该海域摩阻流速呈现夏季大于冬季、大潮大于小潮的规律,涨落急摩阻流速的差异呈现出夏季小、冬季大的特点。夏冬两季涨落急时刻的摩阻流速可用近表层流速进行估算,该海域深槽摩阻流速约为近表层流速的0.06倍。

Characteristics of seabed shear velocities in radial sand ridges area

Based on the vertical distribution of velocities data in a radial sand ridges area of the south Yellow Sea in summer and winter, a Karman-Prandtl equation is adopted to estimate the shear velocities in seabed deep grooves. The spatial and temporal distributions of shear velocities are analysed and a new method of quickly estimating shear velocity is described. The results show that during maximum ebb and maximum flood, flow velocities follow a logarithmic distribution over the depth, with an average of 7.4 cm/s in summer, which has a decreasing tendency from north to south and from nearshore to offshore, and an average of 6.0cm/s in winter, which has a decreasing tendency from middle to north and south and from nearshore to offshore. Shear velocities in summer are greater than those in winter, and the ones in spring tide are greater than those in neap tide. The difference between shear velocities during maximum flood and ebb is small in summer and becomes large in winter. Shear velocities can be quickly estimated by using near-surface velocities in summer and winter, and it can be concluded that shear velocities roughly equal six percent of the near-surface velocities at the same locations in radial sand ridges area.