黄河口悬浮泥沙时空动态及其驱动机制

Temporal and spatial dynamics of suspended sediment and its driving mechanism in the Yellow River Estuary

受径流输沙、风浪、潮汐等影响,河口近岸海域悬浮泥沙具有显著的时空变化。本文基于小时分辨率的GOCI遥感影像,利用最优遥感反演算法,结合空间分析和统计方法,深入研究黄河口及邻近海域悬沙时空动态特征及驱动机制。结果表明,径流输沙对悬沙浓度的影响以河口近岸区为主,高径流输沙对悬沙浓度分布影响可达距岸约20 km,并向孤东近岸方向扩散。大风可引起清水沟老河口区泥沙强烈再悬浮,形成高浓度悬沙区。涨落潮对小时尺度的悬沙浓度影响显著,并影响悬沙的南北扩散。大潮悬沙浓度变化和扩散范围均大于小潮,潮流流速不同是造成该差异的主要原因。水深与悬沙浓度之间存在较明显的负相关关系,根据不同驱动因素的差异,悬沙浓度随着水深的增加呈现出指数型、幂函数型、线性3种关系。

Affected by fluvial sediment discharge,wind waves and tides,etc.,suspended sediment in estuaries and adjacent waters has significant temporal and spatial changes.Based on the GOCI remote sensing images at hourly resolution,this paper uses the optimal remote sensing inversion algorithm,combined with spatial analysis and stat-istical methods to deeply study the temporal and spatial dynamic characteristics and driving mechanism of suspen-ded sediment in the Yellow River Estuary and adjacent waters.The results show that the impact of fluvial sediment discharge on the concentration of suspended sediment is concentrated in the nearshore area of the estuary.The im-pact of high fluvial sediment discharge on the distribution of suspended sediment concentration can reach about 20 km offshore and spread to the Gudong nearshore area.Strong winds can cause intensive resuspension of sediment near the old river mouth of Qingshuigou,forming a high-concentration suspended sediment area.The flood and ebb tides have a significant impact on the hourly-scale suspended sediment concentration,and affect the dispersal of suspen-ded sediment from north to south.The variation and dispersal range of the suspended sediment concentration in the spring tide are larger than that of the neap tide due to different tidal flow velocities.There is an obvious negative correlation between water depth and suspended sediment concentration.According to the difference of driving factors,the suspended sediment concentration present exponential,power function,and linear relationships with the increase of water depth.