悬沙组分对再悬浮过程响应的初步研究——以长江口南槽口门为例

Preliminary study of the response of suspended sediment components to resuspension processes in the mouth of the South Channel, Changjiang River Estuary

根据2011年5月31日至6月3日在长江口南槽口门附近海域投放三角架观测系统获取的沉积动力观测数据以及现场采集的水样和底质样品,进行底部边界层参数、悬沙粒度及悬沙组分分析,以探讨研究区近底部边界层特征和沉积物再悬浮过程。结果表明,研究区海域的悬沙以粉砂组分为主,潮周期内近底部流速与相应层位的悬沙浓度变化呈正相关,存在显著的再悬浮作用。分析发现,随着水体中悬沙砂组分的增加,再悬浮通量随之显著增加;砂组分减小,则再悬浮通量亦减小。因此,悬沙砂组分是对再悬浮过程响应的敏感组分,在一定程度上可指示和"示踪"再悬浮效应。

Based on the sediment dynamics data obtained using a tripod observation system deployed in the mouth of the South Channel in the Changjiang River Estuary, we investigated the bottom boundary layer characteristics and resuspension processes in the region. In addition, we analyzed water samples using a Malvern Mastersize 2000 laser granulometer to obtain the grain-size distribution curves of the suspended sediments. Our results indicate that the sediments in this area are mainly silt. There was a good linear relationship between the near-bottom current ve- locity and suspended sediment concentration; this indicates the occurrence of strong resuspension events. The sand component of the suspended sediment increased with resuspension flux and vice versa. Thus, the sand component of suspended sediments could be used as a proxy of resuspension events.