长江口悬沙浓度时空变化研究——以2012年和2013年洪季为例

Spatial and temporal variation of suspended sediment concentration(SSC) in Yangtze estuary: a case study on flood seasons of 2012 and 2013

河口悬沙浓度及其变化具有重要的生态学、地貌学和工程学意义。2012和2013年7月,在长江口南支、南港、北港、南槽、北槽、口外海滨共10个观测点进行了双潮准同步观测,分析了洪季悬沙浓度的平面、垂向变化特点以及大、小潮和年际差异。结果表明:测点平均悬沙浓度沿口内河槽变化不大;大潮悬沙浓度的纵向差异明显大于小潮;2013年洪季悬沙浓度纵向差异大于2012年;最大浑浊带的位置与最小水深(拦门沙)、最大潮差、盐度锋和砂到泥底质的突变带相吻合。长江口悬沙浓度的平面格局存在显著的时间变化和空间垂向变化,反映了径流(及其悬沙浓度)、潮汐、波浪等因素的不同组合对河口泥沙运动的复杂影响。

The suspended sediment concentration （SSC） at estuary has important geomorphological significance on ecology, geomorphology and engineering. In this research, the plane and vertical variation, spring and neap variation, inter - annual vari- ation of SSC in the sites of south branch, south channel, north channel, south passage, north passage of Yangtze estuary and its adjacent coastal area are analyzed based on the simultaneous observations at ten measuring points during the spring and neap in July 2012 and July 2013. The results include： the SSC changes little along the inner estuary. The longitudinal difference of SSC during spring tide is significantly greater than that during neap tide. The horizontal difference of SSC in lower runoff year of 2013 was significantly greater than that in 2012. The location of turbidity maximum zone corresponds well with the minimum water depth, maximum tidal range, salinity front and the mutation belt from sediment to bottom mud. The plane features of SSC in Yan- gtze estuary show a significant temporal and vertical variation, which reflects that the runoff （with its SSC） , tides, waves and other factors have a complex co - effect on the sediment movement in estuary.