九龙江河口区悬沙浓度的实测与模型结果对比研究

Comparison of field measured and model estimates of suspended sediment concentration in Jiulong River Estuary

根据现场观测获取的高分辨率数据,采用3种悬沙浓度模型进行验证、对比,结果显示:与实测结果相比,波浪浓度模型计算结果效果较差,平流与波流联合浓度模型获得了较好的结果;平流、波流联合模型计算的浓度峰值区与实测峰值区有相位差,其主要与海底泥沙持续性侵蚀、床面泥沙供应量以及泥沙的扩散、沉降有关;无量纲分析结果显示,整个观测期间或单个涨、落潮期间无法直接通过无量纲参数Z反演回归现场悬沙浓度,而中、小潮阶段,在切应力到达峰值前,无量纲参数Z与浓度线性相关性较好,利用其反演回归浓度具有一定的可能性;参考浓度Ca的计算对于浓度模型至关重要,为了使浓度模型计算结果更加准确,对参考浓度Ca的计算方法进行改进十分必要。

By using the field data of high resolution, three suspended sediment concentration models are tested and compared. The results show that the concentrations computed by the wave concentration model are poor compared to field data, however, the other two models gain good results. There are phase difference between the field data and model computed concentration peak areas,the reasons of disagreement are eontinued erosion of the sea bed, the available amount of eroded sediment, and diffusion and settlement of sediment. The di- mensional analysis shows that the in-situ concentration can not be inverted by dimensional parameter Z during the observation periods or a single flood or ebb tide. However,in neap and middle tide,before the bottom shear stress reaching the peak value,the dimensional parameter Z has a good linear relationship with sediment con- centration, so there is a possibility of inverting in-situ concentration by dimensional parameter Z. The reference concentration Ca is crucial to the concentration models,for more accurate calculation resuhs,it is necessary to improve the calculation methods for the reference concentration Ca.