悬沙矿物组分对盐度测量的影响

Influence of mineral components of suspended sediment on salinity measurement

选用石英砂、高岭土及两者的混合物模拟悬沙矿物,利用温盐深剖面仪CTD75M测定不同初始盐度和悬沙浓度下的水体盐度.试验结果表明,测量盐度随初始盐度的减小、悬沙浓度的增大以及矿物组分密度的减小而减小.运用有效介质渗透模型和Maxwell电导率模型分析含沙盐水的电导率;试验数据与电导率理论公式拟合良好,显示悬沙所占体积是影响相对电导率的主要因素.对已有文献的试验数据进行分析,结果表明:基于悬沙浓度的经验盐度修正公式在悬沙密度不同的沿海海域并不适用,具有区域局限性.为此提出基于悬沙体积分数的理论盐度修正公式,提高公式的适用范围.

Quartz,kaolin and their mixture were used to simulate suspended sediment minerals.Salinity was measured by CTD75M in different initial salinities and suspended sediment concentrations.Results indicate that the measured salinity decreases with the decrease of initial salinity,the increase of suspended sediment concentration and the decrease of mineral component density.Effective medium percolation model and Maxwell conductivity model were applied to analyze the electrical conductivity in turbid water.The experimental data fitted well with the above theoretical conductivity formulas.Results indicate that the volume of suspended sediment is the key factor affecting the relative electrical conductivity.The experimental data of the existing literature were analyzed,indicating that the empirical salinity correction formula based on suspended sediment concentration has regional limitations,which is not applicable in coastal waters with different suspended sediment densities.Hence,a modified formula of theoretical salinity based on suspended sediment volume fraction was proposed to improve the applicable scope of the formula.