基于高光谱的邯郸市土壤重金属统计估算模型研究

Study on the Statistical Estimation Model of Soil Heavy Metals in Handan City Based on Hyper-spectral

土壤重金属富集严重制约城市发展,对居民健康造成潜在威胁。该研究旨在定量估算土壤重金属含量,提高土壤重金属监测时效性,从而为土壤保护管理工作提供决策参考和理论支持。该文依据化学检测所得土样重金属含量与地物光谱仪(ASD)获取的土壤反射光谱数据,通过对土壤重金属光谱特性的分析,确定光谱反演特征波段,研究并建立了邯郸市土壤重金属基于不同光谱变换指标的多元逐步回归(SMLR)和偏最小二乘回归(PLSR)统计估算模型,通过模型验证与对比,探索邯郸市土壤各重金属含量的最优反演模型。结果表明:(1)微分处理能普遍改善模型预测效果,二阶微分指标的PLSR与MLSR模型效果较佳;(2)PLSR与SMLR两种建模方法相比,总体上PLSR建模和预测的均方根误差RMSE较小、模型修正系数Adjust R^2较大,表明PLSR模型预测效果更好;(3)基于反射率倒数对数的二阶导数的PLSR模型反演效果较优,其中Cu、Ni、Zn、Hg,检验精度Adjust R2均超过0.8。

The accumulation of heavy metals in the soil severely restricts urban development and poses a potential threat to the health of residents,which has aroused great concern from all walks of life.Therefore,based on heavy metal content determined by chemical test and soil reflectance spectral data measured by spectrograph(ASD)in soil samples,the characteristic band of spectral inversion was determined through analyzing the spectral characteristics of soil heavy metals.The statistical estimation models of Stepwise Multiple Linear Regression(SMLR)and Partial Least Squares Regression(PLSR)for heavy metals in soil of Handan city were established based on different spectral transformation indexes.The optimal inversion model of soil heavy metals for Handan city were explored by verifying and comparing the models.The results showed that:(1)Differential processing can improve the model prediction effect,and the PLSR and MLSR models of the spectral second-order differential index has performed better.(2)Compared with SMLR,modeling and forecasting’s Root Mean Square Error(RMSE)of PLSR is smaller and the model correction coefficient Adjust R^2 is larger,so,it proved that the PLSR model prediction effect is better.And(3)the PLSR model based on the second derivative of the inverse logarithm of the reflectivity has better inversion results.Among them,the inspection accuracy adjustment R2 of Cu,Ni,Zn and Hg all exceeded 0.8.The study aims to quantitatively estimate the heavy metal content of soil and improve the timeliness of soil heavy metal monitoring,thus providing decision-making reference and theoretical support for soil protection and management.