汕头近岸海域表层沉积物粒度特征及其输运趋势

对汕头近岸海域70个站位表层沉积物作了粒度分析和粒度参数计算，以探讨沉积物粒度分布特征。分析结果显示，研究区表层沉积物可划分为9种底质类型，以黏土质粉砂（YT）、砂质粉砂（ST）和砂-粉砂-黏土（S-T-Y）为主；砾、砂、粉砂和黏土的平均含量分别为1.4％，29.2％，51.0％，18.4％。平均粒径在0.12~7.30 之间变化，平均值为5.53 ；分选系数、偏态和峰态值的变化范围分别为0.50~2.94，-0.65~0.30和0.63~2.67，对应的平均值为1.82，-0.02和1.11。根据粒度分析结果，结合系统聚类方法和因子分析方法将研究区分为四类沉积区，分别代表不同的沉积环境，并应用GSTA模型分析了沉积物净输运趋势。结果显示，在汕头港水深＜10 m的海区，径流来沙和海域来沙有在榕江入海口和近岸汇聚的趋势；水深＞10 m的海区，沉积物呈现出明显的沿海岸线东北向输运的特征；在柘林湾，沉积物主要表现为弱的由海岸/海岛向海湾输运的特征。粒径趋势模型所揭示的这种沉积物输运格局与研究区的物源和水动力状况较好吻合，可为研究区港口建设和航道管理的决策提供参考资料。

Grain Size Characteristics of Surface Sediments and Their Transport Patterns over the Coastal Waters of Shantou City,Guangdong Province

Grain size analysis and parameter calculation have been carried out based on 70 surface sediments collected from the coastal waters of Shantou City, and characteristics of frequency distribution have been researched. The results show that the surface sediments of the area are made up of 9 kinds of sediment types, the main types are clayey silt, sandy silt and sand-silt-clay. The content of gravel, sand, silt, and clay in the surface sediments is 1.4%, 29.2%, 51.0 %, and 18.4 %, respectively. The mean grain size of sediments in this area is 0.12~7.30  and the average is 5.53 . The coefficient of sorting is 0.50~2.94 and the average is 1.82. Skewness is -0.65~0.30 and the average is -0.02. Kurtosis is 0.63~2.67 and the average is 1.11.  The modern sedimentary environment in coastal waters of Shantou can be classified into 4 types by system cluster analysis and factor analysis. Spline interpolation method was employed to the data of grain size parameters over the study area. Then, the sediment transport trends were simulated by using GSTA (Grain Size Trend Analysis) model. The grain size trends analysis shows that: In Shantou harbor that the water depth ＜10 m, sediments from the runoff and sea were converged to the estuaries and offshore; Sediments in Shantou harbor that the water depth ＞10 m are transported towards the northeast along the coast. In Zhelin Bay, the sediments’migration trends are from coasts/islands to bay. This pattern is highly consistent with the provenance of sediments and the local hydrodynamics, which could be applied to the decision-making in port and waterway engineering.