科尔沁沙地几种固沙植物光谱-生物量模型构建与分析

在控制背景反射噪音、植被盖度和水分含量的条件下,利用ASD光谱仪对科尔沁沙地4种主要固沙植物杨树(Populus spp.)、黄柳(Salix gordejevii)、小叶锦鸡儿(Caragana microphylla)、樟子松(Pinus sylvestris)光谱反射特征和地面光谱生物量模型构建进行了研究.结果表明:科尔沁沙地4种主要固沙植物光谱反射曲线的趋势基本一致,但是在620～670 nm与841～876 nm波长范围内存在差别,其中在波长620～670 nm最易识别的植物为小叶锦鸡儿,其次是黄柳、杨树,在波长841～876 nm范围最易识别的植物为樟子松、杨树.不同植物的NDVI与盖度和生物量的关系密切,模型拟合精度较高.相对而言,NDVI-盖度模型优于NDVI-生物量模型.不同植物种构建的NDVI盖度模型计算结果相差较小,而NDVI生物量模型的计算结果相差较大.在区域植被生产力遥感监测中,植被样方选择要考虑优势植物种影响,数据采样要涵盖研究区主要植物种.

Spectrum-biomass Models for Several Sand-fixing Plant Species in the Horqin Sandy Land

ASD spectrometer was used to the study on the spectral reflectance of four kinds of sand-fixing plants Populus spp., Salix gordejevii, Caragana microphylla and Pinus sylvestris in Horqin sandyland under the controlled background reflectance noise, vegetation coverage and plant water content, and its ground spectral biomass models were analyzed by using NDVI and plant coverage and above ground biomass, respectively. The results showed that the trend of spectral reflection curves of four kinds of sand-fixed plant species was basically similar, but there were differences in wavelength of 620-670 nm and 841-876 nm. C. microphylla was one of the easiest plants to be distinguished in wavelength of 620-670 nm, following S. gordejevii and Populus spp., P. sylvestris and Populus spp. were easy to be distinguished in the wavelength of 841-876 nm. The relationship between NDVI and vegetation coverage and biomass was very close for the four, and the fitting precision of the models were highest. Compared with them, the models of NDVI-vegetation coverage were better than the NDVI-biomass because the differences of calculated results by the NDVI-coverage models were very smaller than the calculated results by the models of NDVI-biomass of these. However, the influence of dominant plant species should be paid more attention and conformed them involved in the quadrats sampling during remote sensing monitoring in regional vegetation productivity.