辐射沙洲西洋水道激流特征及成因分析

利用1980年和2001年的激流资料和2008年新测的激流水沙资料,对辐射沙洲西洋水道激流特征及成因进行了分析.结果表明:(1)激流具有流速特别大、流向变化小及各层水体含沙量与流速响应良好的特征;(2)一方面,西洋水道喇叭口状的特殊地形易产生涌潮现象,但激流时刻未出现异常潮位变化;另一方面,激流各层流速和含沙量均同时突增,其中底层流速最大为3.71 m/s,最大含沙量为14.94 kg/m3,而风应力不可能使近10 m深的底层海流产生如此大的流速并获得掀起大量底层泥沙的巨大能量,且相邻测站未同时测得激流,故假潮和风应力均不是激流的必要成因,今后应从潮流的辐合和特殊的地形条件两方面进一步探讨激流现象的形成机制.

Analyses on characteristics and genesis of storm current in Xiyang channel of radial sand ridges area

The characteristics and genesis of storm current in Xiyang channel of the radial sand ridges area were analyzed according to the hydrology data (1980 and 2001) and new measured (2008) hydrology-sediment data. Results indicate that the fairly large value and minor variation of direction in the storm current velocity, and the sediment concentration at each observation level responds well to the velocity. For one hand, tidal pore generally resulted from the special bell-mouth topography in Xiyang channel, while no abnormal change in tidal level occurred with storm currents. On the other hand, there exists a surge of velocity and sediment concentration in storm current at each level instantaneously with maximum velocity of 3.71m/s and maximum sediment concentration of 14.94kg/m3 at the bottom. However, wind stress cannot generate such large velocity maintaining huge energy to raise the massive sediments from the bottom current with a depth of 10m. Besides, no storm current was observed at the neighboring stations at the same time. Therefore, both the seiche and wind stress are not the essential factors for the genesis of storm current. A further study on the formation mechanism should be conducted based on the convergence of tidal current and special topography henceforth.