摘要
2017年7月27日,在云南省剑湖湿地中,利用ASD Filed Spec 3光谱仪和CCM-200 Plus叶绿素仪,分别测量了菰(Zizania caduciflora)的反射光谱和叶绿素含量指数(chlorophyll content index,CCI);利用原始光谱反射率以及经一阶微分和连续小波变换的反射率数据,对菰的反射光谱特征进行了研究;分析原始光谱反射率、一阶微分的反射率、"三边"参数、经Mexican Hat小波变换的反射率的小波系数与叶绿素含量指数之间的关系,筛选出显著相关的变量,采用多元逐步线性回归方法,建立叶绿素含量指数的估算模型,并检验估算模型的精度。研究结果表明,菰与健康绿色植物的原始反射光谱特征相同,利用经一阶微分和连续小波变换的反射率数据,可以更好地提取菰反射率信息和分析菰的反射光谱特征;菰的所有波段的原始反射率都与叶绿素含量指数不相关,但是经过一阶微分和小波变换后的反射率,其在一些波长范围内与叶绿素含量指数显著相关;在同一环境下生长的菰叶绿素含量差异明显;在建立的3个叶绿素含量指数估算模型中,利用小波系数建立的回归模型的估算精度相对较高,其决定系数为0.310,均方根误差为6.725。
The reflectance spectra and chlorophyll content index(CCI) of Zizania caduciflora were measured using ASD Filed Spec 3 spectrometer and CCM-200 Plus chlorophyll meter in Jianhu wetlands, Yunnan province in July 2017. The spectral reflectance characteristics of Zizania caduciflorawere measured with original spectral reflectance, spectral reflectance of first order differential and spectral reflectance of continuous wavelet transformation. The relationship between the original spectral reflectance, the first-order differential reflectance, the"three-edge"parameters, the wavelet coefficients of the Mexican Hat wavelet transformed reflectivity and the chlorophyll content index was analyzed and the significant correlative variables were screened out.In addition, multivariate stepwise linear regression was used to establish the estimation models of chlorophyll content index and test the accuracy of the estimation models. The results showed that the original reflectance spectra of Zizania caduciflora were the same as those of healthy green plants. The reflectance spectra of Zizania caduciflora could be better extracted and analyzed by using the first-order differential and continuous wavelet transform data. The original reflectance of all bands of Zizania caduciflora was not correlated with chlorophyll content index, but after the first-order differential and continuous wavelet transforming, the reflectance spectra of Zizania caduciflora could be better extracted and analyzed. The reflectivity after fractional and wavelet transforming was significantly correlated with the chlorophyll content index within certain wavelength ranges. The chlorophyll content of Zizania caduciflora growing under the same environment was significantly different. In the three chlorophyll content index estimation models, the regression model basing on wavelet coefficients had relatively high estimation accuracy with the determination coefficient was 0.310 and the root mean square error was 6.725.
作者
余哲修
张超
黄田
张一
罗恒春
牛晓花
YU Zhexiu;ZHANG Chao;HUANG Tian;ZHANG Yi;LUO Hengchun;NIU Xiaohua(Forestry College,Southwest Forestry University,Kunming 550224,Yunnan,P.R.China)
出处
《湿地科学》
CSCD
北大核心
2018年第6期742-748,共7页
Wetland Science
基金
国家自然科学基金项目(31460195和31660236)
云南省农业基础研究联合专项项目[2017FG001(-017)]资助
关键词
菰
叶绿素含量指数
反射率变换
估算模型
剑湖湿地
Zizania caduciflora
chlorophyll content index
reflectance transformation
estimation models
Jianhu wetlands
