黄河口的变迁对黄河冲淡水分布的影响

CHANGES OF THE DILUTED WATER DISTRIBUTION CAUSED BY THE FLUVIAL PROCESS OF THE HUANGHE RIVER ESTUARY

利津站的水文资料显示,黄河流入渤海的平均年径流量为4.93×10~10m^3,输入海中的平均年输沙量为1.34×10~12kg(钱意颖等,1993)。黄河的年径流量仅为长江的二十分之一,但其年输沙量却为长江的2.26倍,如此大量的泥沙流入海中,不仅造成了河口区的严重淤积,而且也对口门外滨海大陆架区的海洋生态环境造成了很大的影响。因此研究黄河尾闾不同流路时期黄河冲淡水的分布与变化将有助于了解河口外余流场的分布变化及泥沙运行机制。研究表明,黄河冲淡水的分布变化除了取决于其径流量的变化外。

The Huanghe River tail (HRT) has changed channels twice since 1964, Diao-kouhe Channel (from Jan., 1964 to May, 1976) and the Qingshuigou Channel (from May, 1976 up to now). In the Diaokouhe Channel period, the river tail flowed roughly northward into the Bohaiwan Bay, but since May, 1976, has flowed into the Laizhouwan Bay from the Qingshuigou Channel. The major results of the analysis on the distributional features of the Huanghe River Diluted Water (HRDW) in both periods are presented in this paper as follows. (1) In the Huanghe River (HR) flood season the HRDW exists off the water-running mouth and is different from the Baonan coastal water. The core salinity of the HRDW is less than 27 and its thickness is not greater than 10m. The HRDW salinity at its outer boundary can reach 29.5, with corresponding thicknees not greater than 15m. (2) In the flood season, the behaviours of the HRDW are different not only in the different HRT periods but also in the different stages of the same HRT periods. (3) The extent and direction of the HRDW not only has monthly variations due to the HR’s mean runoff discharge but also reveals a weekly fluctuations owing to the intermittent runoff in the HRT. (4) During the period of the Qingshuigou Channel, generally speaking, the HRDW spreads northeastward in the flood season, but the spreading direction is significantly affected by flood-ebb process, which is to say [that the flood tide cause the HRDW to spread to the southeast and the ebb tide to the northeast.