【摘要】 <正> 由于无潮区附近具有潮差小、潮流强等特点,因而它对建港的港址选择有重要意义。黄河三角洲以泥沙多而闻名于世,但在口门附近泥沙运动并非到处相同,主要受海洋动力因于的制约,其中以浪、流、潮的影响最为明显。潮流、余流对5米等深线以外海区泥沙的启动和搬运起主要作用(因水较深,浪的影响要比岸边小得多),因此,开展近海区的潮流、余流研究是非常重要的。一般来说,在潮流强的地方,不仅悬移的泥沙难以沉淀,甚至一些原有的沉积物也能在强潮流的作用下,逐渐被搬移他处,因此在强潮流区海底较硬。例如5号桩(119°00′E,38°01′N)的东北方15米水深的地方,潜水员下去埋捕砂器时,必须使用铁铲挖坑。现在黄河口门3米水深处,也是一个强流带,流速可达到120-140厘米/秒。潜水员潜入水下观察,发现那里的海底也很硬。更多还原

【Abstract】 It is very important to study the nontidal region, because characteristics in this area are very useful to us, for example, the tide range is small and the tide current is very strong. Suspended load isn’t easy to deposite and the bed load is easy to "move along the sea bed.Since 1936 many scientists think that there is a nontidal point M2 in the old eatuary (38°-38°10’N, 119°-119°20’E), and have determined the location of nontidal point. According to our observation, it isn’t a nontidal point but a nontidal line. This line is located near the section B. On the 15th day of lunar calendar this line is just located at section B, and in other days this line moves toward section A, but does’nt arrive in section A. The tide data that have been observed on coast tide stations give eloquent proof of fact of nontidal line. In this region of near nontidal line the current speed is more than 90 cm/sec., and the maximum is 120 cm/sec. The minimum of tide range is about 30 cm and the maximum is about 100 cm. During the flood tide the current direction is south-east, and north-weat during the ebb tide. The residual current speed on section B is about 0.2 knot,and flow into north-west.更多还原