【摘要】 对干旱区土壤盐渍化的高光谱特征进行研究,分析并阐明高光谱精度的影响因子及变换形式,这对定量测定土壤盐碱程度具有重要意义。以陕西定边地区盐碱土壤为研究对象,通过分析区域土样的高光谱数据和室内测定的电导率与全盐含量数据,研究了同一耕作、施肥和灌溉措施下土壤电导率和全盐量的关系,并比较了电导率和全盐量两者的相关关系,分析两者与不同光谱指标(光谱反射率、反射率倒数、反射率对数、反射率一阶微分及反射率对数一阶微分)的相关性以及二者高光谱反演的精度。结果表明:(1)电导率(x)与含盐量(y)之间存在正相关关系且R~2=0.96,达到显著水平;(2)电导率与光谱反射率之间的相关性要优于全盐量,在土壤盐渍化的敏感波段表现尤为突出,遴选敏感光谱波段为350~1 000nm;(3)以电导率构建的偏最小二乘回归模型的决定系数和均方根差优于全盐量。研究表明该区域的土壤高光谱信息对土壤电导率的响应较全盐量敏感,以电导率为监测指标的高光谱反演精度明显要高于全盐量。该结果可为提高上壤盐渍化高光谱监测精度提供科学支撑。更多还原

【Abstract】 S_t udying on the high spectral features of soil salinization in arid areas,analyzing and illuminating the impact factors and transform model of the precision of high spectral is of great significance to the prediction of the degree of soil salinization.The study was conducted in the saline-alkali soil in Dingbian of Shaanxi Province.Hyperspectral data of soils were obtained.The total salt content（S_t ）and electrical conductivity(EC_1∶5)of soil were measured with a soil∶ solution ratio of 1∶5(EC_1∶5).Relationships between S_t and EC_1∶5 were studied under the same tillage pattern,fertilization and irrigation.Correlations between hyperspectral indices and S_t and EC_1∶5,were analyzed.The inversion accuracy of S_t using hyperspectral technique was compared with that of EC_1∶5.The results showed that the significant positive relationship was found between S_t and EC_1∶5（R²=0.96）.The correlation between EC_1∶5 and continuum removal was better than S_t ,especially in the sensitive bands（λbetween 350 nm and 1 000 nm）.The coefficient and mean square root of the partial least squares regression model which was determined by EC_1∶5 were better than those determined by S_t .Therefore,the responses of high spectral information to S_t were more sensitive than those of high spectral information to EC_1∶5.Accuracy of S_t predicted by high spectral was higher than EC_1∶5.The results of this study can provide a theoretical basis for improving hyperspectral remote sensing monitoring accuracy of soil salinization.更多还原