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本文着重研究九龙江口 厦门港冬季小潮实测的各潮时盐度锋面 ,发现其具有锋面宽度窄、盐度梯度很大 ,平面上等盐线大致成西北 东南走向、横断面上则较多呈向南向下倾斜的特征 ,其锋面盐度在 1 5～ 2 7之间 ,锋面宽度约在 2 .6～4.3km之间 ,盐度梯度在 2 .1～ 2 .6km-1之间 ;但盐度锋面区的位置、宽度和盐度梯度随潮位、水深的变化而变化。落急时各层盐度锋面都在象鼻嘴与屿仔尾连线以西 ,并随水深的增加不断向西推移 ,退潮时九龙江冲淡水与西港海水的交汇处存在“退潮流锋面” ,其上辐聚作用强烈 ,使海表漂浮物聚集在等盐线约为 2 5 .5之处形成“流隔线”现象 ;在两个横断面上 ,盐度由南向北、由上至下逐渐升高 ,锋面由断面的中部表层向南部底层倾斜 ,表明低盐的九龙江冲淡水主要沿南岸上层向外港运移。在涨急时 ,除表层盐度分布较为特殊外 ,中、底层的盐度分布与落急时相应层次的相似 ,表明本河口区普通存在“盐楔”现象。
This paper focuses on the tide-time salinity fronts measured by the winter tide in Xiamen Port of Jiulong River Estuary. It is found that the salinity fronts have narrow frontal width and large salinity gradients, and the salt lines in the plane are roughly the northwest and southeast directions. South-downslope features, the frontal salinity is between 15 and 27, the frontal width is between 2.6 and 4.3 km, and the salinity gradient is between 2.1 and 2.6 km-1; however, The location, width and salinity gradient of the salinity frontal region vary with tide level and water depth. In the event of an emergency, the salinity front at all levels was connected to the west of the trunk line of the nose mouth and the island of Lantau and continued westward as the water depth increased. At the junction of the flushing waters of the Jiulongjiang River and the Western Harbor at low tide, there was a “tidal current front” , On which the convergence effect is so strong that the floating debris of the sea surface accumulates at a position where the salt line is about 25.5 and forms a “flow barrier” phenomenon. On both cross sections, the salinity ranges from south to north, From the middle surface of the section to the southern basement, the frontal slope of the frontal slope shows that the low salt waters of the Jiulongjiang flushing mainly migrate to the outer ports along the upper south bank. Except the surface salinity distribution is rather special, the salinity distribution in the middle and lower layers is similar to the corresponding level at the time of emergency, which indicates that the “salt wedge” phenomenon exists in this estuarine area.