滨海盐渍土可见近红外高光谱特征

Hyperspectral Characteristics of Coastal Saline Soil with Visible/near Infrared Spectroscopy

土壤光谱是遥感监测的物理基础,盐渍化土壤光谱特征研究对于盐渍化土地的监测有着重要的意义。以黄河三角洲地区的滨海盐渍土为研究对象,通过野外土壤样品采集和高光谱测量,研究在去除水分以及剔除土壤质地影响后,不同盐渍化程度的滨海盐渍土在350~1100nm区间的高光谱反射和吸收特征,并且试图构建光谱预测模型。结果表明:平滑后的光谱曲线能更准确有效地描述光谱的反射特征及吸收峰。不同盐化程度的土壤光谱曲线形态一致,但反射率大小差异较大。连续统去除后,490 nm处轻度盐化土吸收最小,在760~920 nm区间重度盐化土的吸收更强烈。原始光谱不能预测土壤盐渍化信息,但是二阶微分变换能够提高波段敏感性,建立的光谱预测模型能够基本满足预测要求。

Soil spectrum is the physical basis of monitoring with remote sensing,the research of saline soil spectral characteristics is of great significance for monitoring soil salinization. In this paper,coastal saline soil took from the Yellow River delta was selected as the research object. Through field sampled and indoor processing,Indoor spectra(350~1 100 nm)of coastal saline soil were measured. The characteristics of hyperspectral reflectance and absorption with different salinity were studied after eliminating the influence of moisture and soil texture,and then soil spectral prediction model was built. The results show that the reflection characteristics of spectra and the absorption peak could be decrypted more accurate and effective after smoothed spectral curves.The soil spectral curves with different salinity degree were similar and parallel in shape,while there were greatly differences among them. no obvious rule. After continuum removal was applied to soil curves,the absorption of light saline soil was minimal at 490 nm. Absorption of severe saline soil was more intense in 760~920 nm.The original spectrum couldn’t predict soil salinization information,while the transformation of second-order differential could improve sensitivity of spectral data,and spectral prediction model could basically meet prediction requirements.