黑土与白浆土径流含沙量反演方法的可行性探讨

Feasibility of Inversion Method of Sediment Concentration in Black Soil and Albic Soil

选择东北地区两种主要土壤类型(黑土与白浆土),配置不同含沙量供试水体,观测水体浊度值与光谱反射率,分析含沙量与浊度、光谱反射率及其几种光谱变换值的关系,探讨了利用水体浊度与光谱特征反演径流含沙量的可行性。结果表明:两种水体浊度值与含沙量呈显著正相关,但误差分析与不确定分析显示二者关系精度还不尽理想。光谱变换的含沙量反演模型中,黑土反射率与白浆土反射率的对数验证精度较好,但均低于浊度方法。利用浊度值与光谱特征共同反演径流含沙量的结果表明,黑土反射率的倒数与浊度、白浆土反射率的对数与浊度共同推求含沙量的方法拟合效果最佳,同时降低了误差,提高了精度。研究结果可为水土流失自动化监测提供一定参考。

The possibility of inversion of sediment concentrations with turbidity and spectral characteristics was discussed in this study. The water samples with different sediment concentrations were obtained from Black soil and Albic soil in Northeast China. The turbidity and spectral reflectance of the samples were observed, and the relationships among sediment concentrations, turbidity and spectral reflectance as well as several spectral transformations were analyzed. Results showed that there was a significant positive correlation between turbidity and sediment concentrations, however, this relationship was not ideal by the error analysis and uncertainty analysis. The verification accuracy was better in Black soil by using reflectance and in Albic soil by using logarithm of reflectance,while their precisions were lower than that by using turbidity. The fitting results of sediment concentration were better with inversion models between the reciprocal of reflectance and turbidity in Black soil and between the logarithm of reflectance and turbidity in Albic soil. The third method reduced the error and increased the accuracy. These results would provide a certain reference for the development of automatic monitoring for soil and water conservation.