淤泥质海岸岬湾沙滩沙泥分界特征及机理

Characteristics and mechanisms of sand-mud transition in embayed beach of muddy coast

以浙江省淤泥质海岸岬湾沙滩为研究对象,剖析了影响沙泥分界点位置的主要因素和沙泥分界的影响机理,并提出了岬湾沙滩沙泥分界点高程计算公式。结果表明:潮位、滩前波高、沙滩坡度和潮差是影响沙泥分界点位置的主要因素;沙泥分界点深度与滩前1/10大波平均波高和大潮平均潮差呈正相关关系,与沙滩坡度呈负相关关系;沙泥分界点位置呈现季节性变化和年际变化,夏季沙泥分界点位置向海外移且高程下降、冬季分界点向岸上溯,2020年比2019年的沙泥分界点位置呈现向海外移、高程下降的趋势。

This study focuses on the muddy-coastal headland bay beaches in Zhejiang Province,identifies the primary factors influencing the position of the sand-mud boundary,and analyses the transition mechanism.A depth formula of the sand-mud boundary point in headland bay beaches is proposed.The results show that:the tide level,wave height,beach slope and spring mean tide range in front of the beach are the main factors affecting the location of sand-mud boundary;the depth of sand-mud boundary is positively correlated with the 1/10 wave height in front of the beach and the spring mean tide range,and negatively correlated with the slope of the beach;the position of the sand-mud boundary exhibits seasonal and inter-annual variations.During summer,the sand-mud boundary tends to shift seaward and decrease in elevation,while in winter,it moves landward.Notably,in 2020,compared to 2019,the sand-mud boundary showed a clear trend of seaward migration and a decrease in elevation.