伶仃洋洪季悬沙平面分布特征及成因探讨

The 2D distribution characteristics and formation mechanism of suspended sediment concentration during the flood season in the Lingdingyang Estuary

基于伶仃洋河口2007年洪季(8月)潮流和泥沙现场观测资料,通过实测资料分析结合二维泥沙数值模型的方法,分析其悬沙浓度平面分布特征。结果表明,悬沙浓度从伶仃洋湾顶虎门至湾口沿西槽向海在纵向上呈现出先减小再增大后减小的变化趋势;横向上,西槽最大,东槽和中滩次之;内伶仃岛西北侧海域为含沙量高值中心。悬沙纵向输移机制分析表明,伶仃洋洪季输沙主要贡献项为平流向海输沙、潮汐捕集和垂向环流的向陆输沙,其中后两项在内伶仃岛附近的贡献较大。潮流、径流来沙、径潮强度对比以及地形边界作用为悬沙场平面分布差异的主要成因。

Based on the observed data of current and suspended sediment concentration （SSC） during the flood sea- son （13-14 and 16-17, August, 2007）, by the means of measured data analysis and the TELEMAC-2D numer- ical model, this article reveals the spatial distribution characteristics of SSC in the Lingdingyang Esturay. in the longitudinal direction along west channel, SSC decrease first, then increase, and then decrease again from bay head to open sea; laterally, west channel, east channel and the north of the middle flat are higher SSC areas; the maxi- mal center of SSC is located on the northwest of Neilingding Island. The model of longitudinal material transport reveals that the main reasons of net suspended sediment transport are advection, tidal asymmetry and vertical cir- culation. The effects of tidal current, runoff with sediment transport, solid boundary and topography condition are the main reasons for the 2D distribution characteristics of SSC in the Lingdingyang Estuary.