南海北部海洋雾状层特征及影响因素初步研究

在粤东上升流区和南海北部陆架陆坡区共选取7条断面,通过分析水体的温度、盐度、密度、浊度、叶绿素浓度特征和悬浮体现场粒度平均粒径、体积浓度特征等,初步研究了南海北部海洋雾状层的特征及其受控机制。研究发现粤东上升流区底部雾状层普遍发育,在个别站位存在表层雾状层,高能的近岸浪流作用和来自港湾、河流的泥沙为表层雾状层和底部雾状层提供物源;南海北部陆架陆坡区底部雾状层也普遍发育,在珠江口外的内陆架和外陆架陆坡区表层雾状层比较常见,陆坡区中层雾状层比较发育,本区雾状层的物源主要来自珠江和台湾岛西南部河流的入海泥沙、海底沉积物以及生源颗粒物。南海北部底部雾状层的强度和扩散范围主要受水动力条件、河流入海物质的扩散和底质再悬浮等控制。

A preliminary study on the characteristics of marine nepheloid layers in the northern South China Sea and their influential factors

Seven sections are studied in Yuedong(eastern Guangdong Province, China) upwelling area and the shelf-slope area of the northern South China Sea(NSCS). By analyzing the temperature, salinity, density, turbidity and chlorophyll concentration of seawater, and the mean grain size, volume concentration of suspended particles, the characteristics of the marine nepheloid layers in the NSCS and their influential factors are studied. The results show that the bottom nepheloid layer(BNL) develops widely in Yuedong upwelling area, and the surface nepheloid layer(SNL) exists at few sites. Particle matter in nepheloid layer is mainly from high energy coastal processes and bays, rivers in Guangdong Province.The BNL also develops widely in the shelf-slope area of the NSCS; the SNL often exists in the inner shelf off the Zhujiang River Estuary and the outer shelf-slope area; the intermediate nepheloid layer develops in the slope area. Particle matter in the nepheloid layer is mainly from the Zhujiang River and rivers in southwest Taiwan Island, seabed sediments and biogenous particle matter. The intensity and thickness of the BNL are mainly controlled by hydrodynamic conditions, dispersion of matter by river discharge, resuspension of fine deposites and so on.