黑土土壤水分光谱响应特征与模型

Soil moisture spectral analysis and its spectral model

为揭示土壤水分对土壤反射率的影响机理,并为其他土壤参数遥感监测提供理论支持,以吉林省德惠市黑土野外、室内高光谱反射率为研究对象,运用光谱分析方法与统计分析方法,分析土壤水分光谱特征,建立土壤水分光谱模型,得出以下结论:土壤光谱反射率在400～2500nm范围内主要有5个吸收谷,随着含水量的增加,土壤光谱吸收谷的面积增大;而秸秆光谱反射率在土壤前2个吸收谷附近没有明显的吸收特征;未翻耕土壤由于秸秆残茬的影响,第二吸收谷左右两部分面积比例增大,这一特征可用于判别土壤是否翻种;土壤表层0～5cm含水量与反射光谱数据的相关性强于5～10cm;土壤含水量与土壤光谱反射率之间是指数或线性关系;土壤含水量高光谱模型稳定性较好、精度较高,可以用于土壤含水量的速测.

To improve the method for soil moisture monitoring, uncover the mechanism of moisture effects on soil spectral reflectance, and provide theoretical information for other soil properties＇ spectral analysis and remote sensing monitoring, Black soil samples from Dehui city, Jilin province, China, their field and laboratory reflectance were taken, and derivate, continuum removal and statistical methods were used to analyze soil moisture spectral characteristics and build soil moisture spectral models. The results are as follows： there are five absorption vales on soil spectral reflectance in the region 400 - 2500nm, the vales grow with increasing soil moisture; however, the absorption vales＇ areas of crop residue in the spectral range of the first two vales of soil can be ignored, which can be used to determine whether soil is covered with residue; stubble field shows the characteristics of soil, the five spectral vales are significant, but for the effect of stubble, the minimum value of the second vale moves to longer wavelength, and the proportion of the fight side decreases significantly, which indicates whether the field is furrowed or not; so soil remote sensing should be conducted after field furrowed; the correlation between soil moisture at the depth of 0 - 5cm and spectral data is more remarkable than that at the depth of 5 ～ 10cm; the relationship between soil moisture and reflectance is exponent or linear, which should be considered when other soil properties are remotely sensed; soil moisture spectral models are very stable and accurate, which can be used for quick soil moisture monitoring.