论文部分内容阅读
[目的]对玉米地微波相干和非相干散射模型进行比较分析。[方法]在Stile相干散射模型的基础上提出了针对玉米作物的相干散射模型,模型中使用物理光学(PO)和无限长介电圆柱体近似方法计算玉米叶片和秆的单散射体矩阵,替代了原模型中计算窄叶的单散射体模型,并在模型中考虑了不同散射机制之间相互作用所产生的相干分量。研究中所使用的非相干散射模型为密歇根森林散射模型(MIMICS)。使用吉林省公主岭地区玉米地部分生长周期内的实测数据为以上相干和非相干散射模型的输入参数,分别模拟L和C波段VV和HH极化的后向散射系数,并将这2个模型的模拟结果进行了比较。[结果]该模型在不考虑树干层的情况下,可应用于玉米地后向散射系数的模拟玉米;该相干散射模型在L波段的模拟结果较差,在植被生长初期表现为模拟结果没有明显的规律性;通过相干和非相干散射模型的比较分析,证实由散射机制引起的相干性是较小的。[结论]文中只分析了随入射角变化,相干和非相干散射模型的差异,在以后的研究中,需要进一步分析该差异随植被和土壤参数的变化情况。
[Objective] The comparative analysis of microwave coherent and incoherent scattering models in corn field was carried out. [Method] Based on the Stile coherent scattering model, a coherent scattering model for maize crop was proposed. In this model, single-scatterer matrices of maize leaves and stalks were calculated using physical optics (PO) and infinite-length dielectric cylinder approximation method, In the original model, the narrow-leaf single-scatter model is calculated, and the coherent components generated by the interaction between different scattering mechanisms are considered in the model. The incoherent scattering model used in the study is the Michigan Forest Scattering Model (MIMICS). Using the measured data of some growth periods of maize field in Gongzhuling area of Jilin Province as the input parameters of the above coherent and incoherent scattering models, the backscattering coefficients of the V and HH polarizations in L and C bands were simulated respectively. Simulation results were compared. [Result] The model could be applied to simulated maize with backscatter coefficient without considering the trunk layer. The simulation results of the coherent scattering model in L wave band were poor, and the simulation results were not obvious in the initial stage of vegetation growth By comparing the coherent and incoherent scattering models, it is verified that the coherence caused by the scattering mechanism is small. [Conclusion] In this paper, only the differences of coherent and incoherent scatter models with variation of incident angle are analyzed. In the later study, the variation of this difference with vegetation and soil parameters needs to be further analyzed.