作　　者： ; ; ;

机构地区： 中国科学院地理科学与资源研究所

出　　处： 《第四纪研究》 2010年第5期972-983,共12页

摘　　要： 以钓口流路时期1967年前后的海岸地形为例,研究了沙嘴海岸地形对黄河三角洲沿岸余流场的影响。数值对比试验表明,沙嘴附近的余流流向受地形扰动而不断偏转,使得沙嘴地形特征可能引起局部余环流结构的改变,甚至在沙嘴附近呈现出小的涡环结构,沙嘴对流向的影响随离沙嘴地形距离的增加而渐弱。沙嘴海岸地形还将引起局部流速的增加,并在其附近海域形成高流速区,在忽略沙嘴地形的条件下,一些随沙嘴而生的高流速区范围缩小、流速降低,并向西南移动,甚至消失,原沙嘴前沿余流流速明显减小,随离沙嘴距离的增加,流速差异逐渐微弱。 During the period in which the Yellow River entered the Bohai Sea through an estuary channel which has violently and periodically shifted many times ever since 1855,a profound characteristic of the Yellow River Delta （YRD） evolution is the rapid forming and extending of estuary spits. These spits have important effects on the nearshore current field out of the coastline of YRD. Taking the 1967 YRD coastal topography with three apparently seaward-protruding spits which were respectively developed through three different estuary channels as an example, we studied influence of these spits on residual currents out of the coastline of YRD by three comparative numerical tests which were run respectively in the following conditions： （1）actual topography, （2）topography in which the spits were cut, but the subaqueous topography was remained, and （3）topography in which the spits were cut and the subaqueous topography was also cut. Considering the extreme weakness of thermohaline circulation in the study area which had very shallow water,residual currents out of the coastline of YRD can be simulated by the collective drive of wind and tide. The comparative numerical tests show that the residual current directions near spits are apparently different in the above three topographic conditions. The residual current directions were constantly deflected by topographic disturbance so as to lead to changes of local circulation structures. There were some small vortex-like structures to occur seasonally near spits. Impacts of spits on residual current directions were gradually weakened with increase of distance from spits. The residual current velocities near spits in the condition of actual topography were higher than that in other two conditions, and so there were relative high-velocity zones to have been formed near spits. However, when spits were cut, but the subaqueous topography was remained, the high-velocity zones around original spits would reduce,move or even disappear. When spits were cut out and the sub

关 键 词： 黄河三角洲沿岸 沙嘴 余流

领　　域： [天文地球] [天文地球]