退化伊犁绢蒿荒漠草地特征植物光谱特征

分别对退化伊犁绢蒿(Seriphidium transiliense)荒漠草地上8种特征植物长势较好时期的原始光谱、包络线去除后光谱及一阶微分光谱曲线特征波段进行对比分析,发现在特定波段不同植物光谱反射率特征值与其他植物有明显不同;760-930 nm植物光谱强反射带波段间8种特征植物的反射率值最大相差近40%,反射率从大到小依次为伊犁绢蒿＞萹蓄(Polygonum aviculare)＞骆驼蓬(Peganum harmala)＞画眉草(Eragrostis pilosa)＞地肤(Kochia scoparia)＞弯果胡卢巴(Trigonella arcuata)＞角果藜(Ceratocarpus arenarius)＞叉毛蓬(Petrosimonia sibirica);1 400 nm附近水分吸收带光谱反射率值最大,相差近27%,从大到小依次为伊犁绢蒿＞地肤＞角果藜＞画眉草＞叉毛蓬＞萹蓄＞弯果胡卢巴＞骆驼蓬;从红边位置(P)、幅值(K)识别8种特征植物高光谱特征信息为:除萹蓄P为708 nm外,其他7种特征植物P值均集中在718 nm处;伊犁绢蒿K为0.925 4;叉毛蓬K为0.188 5;萹蓄K为0.685 4;骆驼蓬K为0.799 8;地肤K为0.183 9;弯果胡卢巴K为0.538 7;画眉草K为0.441 6;角果藜K为0.132 7。包络线去除后的光谱红边及峰谷特征与原始光谱曲线相比显得更为清晰、明显。一阶微分对于精确提取该类草地植物光谱特征的红边参数特征值有重要作用。

Spectral features of eight desert range plants on degradation Seriphidium transiliense desert grassland

The characteristics of original spectra, spectra without envelope and the first derivative spectra of 8 desert range plants which growing well on the Seriphidium transiliense degradation desert were analysis and compared in the present study. For spectral reflectance characteristics, there were significant differences among different plants at a specific band with a maximum different value of 40% in reflectance between 760 nm and 930 nm. The reflectivity decreased in the following order: Seriphidium transiliensePolygonum aviculare＞Peganum harmala＞Eragrostis pilosa＞Petrosimonia sibirica＞Trigonella arcuata＞Ceratocarpus arenarius＞Petrosimonia sibirica. The maximum moisture absorption spectral reflectance values was 27% near 1400 nm and the value decreased in the following order: S. transiliense＞K. scoparia＞C. arenarius＞E. pilosa＞P. aviculare＞T. arcuata＞P. harmala. The red edge position (P) of P. aviculare was 708 nm and the values of the other seven plants were same as 718 nm. The amplitude (K) of S. transiliense, P. aviculare, P. harmala, E. pilosa, K. scoparia, T. arcuata, C. arenarius and P. sibirica was 0.925 4, 0.685 4 , 0.799 8, 0.441 6, 0.183 9, 0.538 7, 0.132 7 and 0.188 5, respectively. Spectral red edge and peak and valley characteristics without envelope were more clear and obvious compared with the original spectral curves which suggest that the first derivative played an important role in accurately extracting the Red edge parameters of spectrum characteristics of grassland plants.