长江下游及河口区水动力特征

发布时间：2018-05-15 04:29

本文选题：长江 + 河口　；参考：《环境科学研究》2017年03期

【摘要】：基于EFDC模型,构建长江下游及河口区二维水动力模型,对河流和河口区进行整体模拟,研究长江下游及河口区水动力特征.模型在空间上采用变尺度、拟合边界的矩形网格,在时间上采用动态时间步长,在模拟过程中自动识别干湿网格,更好地保证模拟精度与效率.利用1998年冬季以及2005年夏季和秋季实测资料,对粗糙高度等敏感参数进行参数率定和验证.结果表明,模拟的潮位和流速与实测成果拟合较好,较好地反映了各水期长江下游及河口区的水动力要素的空间分布特征.应用模型模拟2004—2007年不同水期的水动力过程,并对模拟结果进行统计分析.研究显示:从空间来看,河道、河口流态存在显著差异,涨、落潮流场空间分布差异大;受径流和潮差的相互作用,潮流界在河口以上150~450 km之间变动,径流量和潮流界位置具有对数相关关系.从时间来看,径流量丰平枯变化大,对潮流量和径流入海时间都有一定的影响,潮流量、径流入海时间与径流量之间也存在明显的定量关系.
[Abstract]:Based on the EFDC model, the two-dimensional hydrodynamic model of the lower reaches of the Yangtze River and the estuary is constructed, and the hydrodynamic characteristics of the lower reaches of the Yangtze River and the estuaries are studied. The model adopts rectangular mesh with varying scale and boundary fitting in space, and uses dynamic time step in time to identify dry and wet mesh automatically in the process of simulation, so that the simulation accuracy and efficiency are better guaranteed. Based on the measured data in winter of 1998 and summer and autumn of 2005, the parameter rate of sensitive parameters such as rough height is determined and verified. The results show that the simulated tidal level and velocity fit well with the measured data and reflect the spatial distribution characteristics of hydrodynamic elements in the lower reaches of the Yangtze River and the estuary. The model was used to simulate the hydrodynamic processes in different water periods from 2004 to 2007, and the simulation results were statistically analyzed. The results show that there are significant differences in the river channel and estuarine flow patterns, the spatial distribution of tidal current field varies greatly, and the tidal boundary varies from 150 km to 450 km above the estuary due to the interaction between runoff and tidal range. There is a logarithmic correlation between the runoff and the position of the tidal current boundary. From the point of view of time, there is a great change of runoff, which has a certain influence on the tidal current and the time of runoff entering the sea, and there is a significant quantitative relationship between the amount of tidal current, the time of runoff entering the sea and the runoff.
【作者单位】：中国环境科学研究院;
【基金】：国家水体污染控制与治理科技重大专项(2013ZX07501-005,2012ZX07503-002)
【分类号】：TV13

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