Study on the evaluation of the influences of the Three Gorges Dam construction in China on the marine environment in the East China and Japan Seas

2003年和2004年夏季，利用布设在陆架中区的T/S传感器的卫星跟踪漂移器观测了长江冲淡水的行为。用数值模式再现了气候学显示的CDW的季节变化和漂流者探测到的日变化。数值模式表明，CDW的行为在季节变化和日变化中都受到风应力的强烈影响。漂流者的移动与日风应力的比较也显示出风对CDW移动的显著影响。CDW的水平分布经常与卫星探测到的海洋颜色的水平分布进行比较。浮游植物消耗的营养物质应补充到CDW中。通过测量CDW区的微结构和拉格朗日测量的盐度变化估计垂直涡旋扩散率，表明垂直平流可能对…的增加起到重要作用CDW的盐度更高。估算的垂直速度大小与由漂流者散度计算的垂直速度大小基本一致。利用营养物质以及温度和盐度进行的水团分析表明，陆架下层的水可能是黑潮温跃层水和少量淡水的混合物。氧-18同位素比值的分布表明，黑潮中间水会间歇性地侵入大陆架底层。横跨对马海峡的常规渡轮茶花线对盐度的监测表明，与东部海峡相比，海峡西部海峡通常受低盐度水的影响较大。但盐度年际变化东航道大于西航道。对日本海深层系泊资料的频谱分析表明，重力惯性内波对深水垂直混合起着重要作用。较少

The behavior of the Changjiang Diluted Water(CDW) was observed by satellite-tracking drifters with T/S sensors deployed in the mid-shelf area during the summer of 2003 and 2004. Both of the seasonal variations in the CDW shown by climatology and the daily variations detected by drifters are reproduced by numerical models. The numerical models indicated that the behavior of the CDW is strongly influenced by wind stress both in seasonal and daily variations. Comparison of the movements of drifters with daily wind stress also shows the significant wind effect on the movement of CDW.The horizontal distribution of the CDW is often compared with that of ocean color detected from satellites. The nutrients consumed by phytoplankton should be supplied into the CDW. Estimation of the vertical eddy diffusivity with measurements of the microstructure in the CDW area and salinity change from the Lagrangian measurements suggested that vertical advection could play a significant role on the increase … More in salinity in the CDW. The magnitude of the vertical velocity estimated is roughly coincident with that calculated from the divergence of drifters' dispersion.Water mass analysis using nutrients along with temperature and salinity revealed that water at the lower layer on the shelf could be a mixture of the Kuroshio thermocline water and the fresh water with a small fraction. The distribution of oxygen-18 isotope ratio suggests that the Kuroshio intermediate water would intermittently intrude into the bottom layer of the continental shelf.The monitoring of salinity by the regular ferry, Camellia line, crossing the Tsushima Strait showed that the western channel of the strait is usually much influenced by the low salinity water compared with the eastern channel. However, the interannual variations in salinity in the eastern channel are larger than those in the western channel. The variations appear to be related to the variation in the volume transport of Changjiang discharge.The spectral analyses for the mooring data in the deep layer in the Japan Sea revealed that inertial internal gravity waves would play a significant role on the vertical mixing in the deep water. Less