基于PROSPECT-D的铜胁迫下小麦叶片光谱辐射传输模型构建

To solve the scientific problem on the physical quantitative relationship between spectral reflectance and copper content of wheat leaves under copper stress, this project is to establish a spectral radiative transfer model of copper-stressed wheat leaves based on the latest version PROSPECT-D of PROSPECT model using measured spectral reflectance and transmittance. The main research contents include: (1) This project is to investigate the retrieval of leaf structure parameters of copper-stressed wheat leaves and to clarify the changing pattern of leaf structure parameter with copper stress level. (2) The specific absorption coefficient (SAC) of biochemical constituents at different wavelengths is to be investigated with numerical inversion. The feature and pattern of SAC curves are to be revealed and its explanatory mechanism is to be preliminarily explored. (3) The accuracy level is to be evaluated by both forward simulation and back forward parameters retrieval, and the model is to be optimized. The final results of this project are to form the physical quantitative relationship between reflectance and copper content of copper-stressed wheat leaves. The achievements of this project will contribute to recognizing the changing pattern of spectral features and its controlling factors of copper-stressed wheat leaves, and provide the physical model foundation for improving the inversion ability and generality of copper content in wheat leaves using hyperspectral remote sensing. This project shows important scientific significance and application prospect for protecting food security and monitoring the environmental heavy-metal (copper) pollution.

针对铜胁迫下的小麦叶片光谱反射率与叶片铜元素含量之间的物理模型定量关系这一科学问题，本项目依托PROSPECT模型的最新版本PROSPECT-D，利用实测的光谱反射率和透射率数据，构建铜胁迫下小麦叶片的光谱辐射传输模型。主要研究内容包括：（1）研究铜胁迫下小麦的叶片结构参数反演，阐明小麦叶片结构参数随铜胁迫程度的变化规律；（2）研究各个生化组分吸收系数在不同波长的数值反演，揭示各个生化组分吸收系数曲线的特征规律，并初步探究其机理解释；（3）从正演和反演两个方面研究模型的精度水平，并实现模型的优化。最终，形成铜胁迫下小麦的叶片光谱反射率与铜元素含量之间的物理模型定量关系。本项目成果将有助于认清铜胁迫下小麦光谱特征变化的规律及其背后的主控因素，为提升高光谱遥感反演小麦叶片铜元素含量的能力和通用性提供物理模型基础，对我国粮食安全保障和环境重金属铜污染监测具有重要的科学意义和应用前景。

矿区植被重金属胁迫遥感监测对于矿区环境保护与治理具有重要意义。本项目依托PROSPECT模型的最新版本PROSPECT-D，构建了铜胁迫下小麦叶片的光谱辐射传输模型。主要研究工作包括：（1）开展了铜胁迫下小麦的叶片结构参数反演，阐释了小麦叶片结构参数随铜胁迫程度的变化规律；（2）开展了各个生化组分吸收系数在不同波长的数值反演，揭示了各个生化组分吸收系数曲线的特征规律，并初步探究了其机理解释；（3）从正演和反演两个方面研究了模型的精度水平，并实现模型的优化。最终，形成了铜胁迫下小麦的叶片光谱反射率与铜元素含量之间的物理模型定量关系。项目取得如下结论：（1）铜胁迫叶片的结构参数值明显大于正常叶片的结构参数值，并且呈现出随着铜胁迫程度的增加而增大的趋势；（2）本研究得到的铜元素吸收系数随波长变化的特征更加科学合理，能够用现有的光谱理论和实验结果更好地进行解释；（3）本研究构建的新模型比起PROSPECT-D模型能够得到更好的铜胁迫叶片的光谱反射率模拟值。本研究有助于认清矿区铜胁迫下植被光谱特征变化的规律及其主控因素，在矿区生态环境保护领域具有重要意义。