长江口附近海域三维悬浮泥沙的数值模拟研究

IOCAS-IR > 海洋环流与波动重点实验室

	长江口附近海域三维悬浮泥沙的数值模拟研究
其他题名	Numerical Study of Suspended Sediment Transport in the Offshore Near Changjiang Estuary
	陈斌
学位类型	博士
	2008-06-12
学位授予单位	中国科学院海洋研究所
学位授予地点	海洋研究所
关键词	长江口附近海域悬浮泥沙数值模拟趋近同化扩散系数
摘要	本文构建了长江口外海域三维悬浮泥沙输运数值模型，其中水动力模型中主要考虑了潮汐潮流、出入径流及风浪等作用，输运模型中考虑了粘性泥沙的絮凝、粘性和非粘性泥沙的再悬浮等过程。并与2006年8月份在长江口外海域获得的定点连续站测流资料及悬浮泥沙的观测资料进行了比较。为了进一步提高模式结果的精确性，采用将动力模式与实测资料相结合的趋近同化方法，在连续方程和泥沙输运方程中分别增加一个松弛项，将模拟结果向已有实测调和常数的控制点推算潮高值和悬沙浓度观测值趋近。数值实验证明，将验潮站资料和泥沙观测资料引入到数值模式中去，可以有效的改善模式的模拟结果。将该方法运用到长江口外附近海域的悬浮泥沙数值模拟当中，并泥沙输运水平紊动扩散系数也做了合理的修改，其模拟结果也得到了不错的改进，所得结果适用于计算长江口外海域的水动力和泥沙输运情况。可以大体得到泥沙在长江口内外分布规律：悬浮泥沙浓度自近岸向外海降低,长江口外123°E以东浓度一般不超过10mg/l，终年悬浮泥沙高值区见于河口区,一般超过300mg/l，以长江口、杭州湾悬浮泥沙浓度最高。悬浮泥沙浓度垂向剖面的计算值与观测数据符合良好。在潮周期中，悬浮泥沙浓度的变化与
其他摘要	Basing on ECOMSED model, a 3-D hydrodynamic-transport numerical model for the offshore area near Changjiang Estuary in the East China Sea has been developed. The hydrodynamic module is driven by tide and wind as well as inflow and outflow currents. Effect of wind generated waves also includes in the current modeling framework. Sediment module includes sediment resuspension, transport and deposition of cohesive and non-cohesive sediment. Settling of cohesive sediment in the water column is modeled as a function of aggregation and deposition. The numerical results are compared with observation data which measured during Aug, 2006 in the East China Sea. To improve the accuracy of results，This paper adds a nudging assimilation method to ECOMSED model, establishing a assimilation model, and tides and suspended sediment concentration in the offshore near Changjiang Estuary is simulated by this model. A relaxation term is added to the continuity equation and sediment transport equation respectively to nudge the calculated value to the observation data. Numerical experiments show that the data assimilation in numerical model which can improve the accuracy of results. This paper apply this method to the simulation of the suspended sediment in the in the Offshore Near Changjiang Estuary, and modify the horizontal diffusivity of the suspended sediment transport, and improve on the result. The distribution of suspended sediment concentration shows that the sediment concentration reduces gradually from the seashore to the offshore area, Suspended sediment concentration eastern of 123°E is less than 10 mg/L. The higher concentration of suspended sediment concentration generally appears at the Changjiang Esturay and the Hangzhou Bay, and exceeds 300 mg/L. The calculation results of concentration profiles are relatively good fitness with observation data. Numerical results of concentration time series in the observation stations show two peaks and two valleys, according with the observation data. It is mainly affected by tidal current. The suspended sediment concentration is related to the tidal current during a tidal cycle, and the maximum concentration appears 1~4h after the current maximum velocity.
页数	127
语种	中文
文献类型	学位论文
条目标识符	http://ir.qdio.ac.cn/handle/337002/1281
专题	海洋环流与波动重点实验室
推荐引用方式 GB/T 7714	陈斌. 长江口附近海域三维悬浮泥沙的数值模拟研究[D]. 海洋研究所. 中国科学院海洋研究所,2008.

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