行道树叶绿素变化的高光谱监测研究

采样分析了城市行道树与对比区相应树种的叶绿素变化,并对由叶绿素变化引起的高光谱响应进行了分析,结果表明:(1)城市环境对行道树叶绿素有重要影响,其中,对针叶树种叶绿素的影响较小,对阔叶树种叶绿素的影响较大;(2)导数光谱与测试树种叶绿素含量关系密切,在740～760 nm附近相关系数达0.83以上;(3)PSSR植被指数与测试树种的叶绿素含量关系密切,幂函数回归的确定性系数达80%左右.以上结论说明:高光谱遥感可以用来监测因城市环境引起的植被叶绿素变化.

Hyperspectral Approaches for Detecting the Roadside Tree Chlorophyll Content Changes at Branches Scale

Effects of urban communication environment on the chlorophyll content of roadside tree leaves were compared with that of corresponding tree leaves growing in a less polluted environment - Jingyue National Forest Park by analyzing samples collected in both areas. Hyperspectral data of those samples were acquired by using ASD Field NVIR Spectroradi-ometer. The results of analysis showed that:(1) The urban environment could cause serious effects on the chlorophyll content of roadside tree leaves, and deciduous tree leaves responded to this effects intensively while for conifers tree leaves this was not the case. (2) Hyperspectral reflectance and its derivative had intimate relation with the chlorophyll content of sampled roadside tree leaves, and the relationship between chlorophyll content of tree leaves and hyperspectral reflectance and its derivatives varied with the wavelength, in blue and short part and near infrared region of spectrum there was a strong correlation between chlorophyll and reflectance and derivatives, the correlation coefficient was above 0. 83 during 740 - 760 nm. (3) PSSR(the pigment specific simple ratio) index had an intimate relation with chlorophyll content, and a power re-gression model was established with the determination coefficient around 0. 80, which showed that it could be used to detect roadside tree leave chlorophyll content change caused by urban communication environment.