【摘要】 作为针叶、枝条和树干的单散射体模型，有限长圆柱体散射模型是微波遥感植被建模的重要基础，但针对实际树干的精确观测数据很少，建模也未考虑表面粗糙度对散射特性的影响。以三维电磁散射模拟软件FEKO和室内多角度多频率后向散射观测数据为基础，分析了树干圆柱体的散射特性，讨论了表面粗糙度对树干圆柱体雷达散射截面RCS(Radar Cross Section)的影响。研究包括：(1)模拟树干圆柱体RCS对圆柱体尺寸、介电常数的响应；(2)FEKO模拟结果与室内测量结果对比；(3)用简化建模和基于真实树干网格模拟的方式探讨粗糙度的影响并对两种方式进行比较。结果显示：(1)尺寸方面，圆柱体RCS随直径的增大逐渐增加，但植物体不同组件RCS呈现出不同的变化规律；(2)介电常数方面，RCS随介电常数的增加逐渐增大，在本实验模拟条件下，含水量每增加10%，介电常数约增加4,RCS约增加1 dBsm；(3)模拟与测量结果趋势一致，R~2最高为0.87，最低为0.5，但绝对值存在一定偏差，RMSE在4～6.5 dBsm之间；(4)树干表面粗糙度对RCS有一定影响，但与波长有关，基于真实树干网格模拟的圆柱体RCS，表面粗糙度对RCS影响程度为：X>C>S波段，且简化建模的方式不能很好地表征树干表面粗糙度。利用高精度模拟和观测，对树干圆柱体散射特性进行了再认识，探究了树干表面粗糙度对其散射特性的影响，为提升植被圆柱体建模精度提供了重要参考。更多还原

【Abstract】 As a single scattering model of conifers, branches and trunks, the finite long cylinder scattering model is an important basis for vegetation modeling of microwave remote sensing. However, there are few accurate observations of the realistic trunk, and the modeling does not take into account the effect of roughness on scattering characteristics. The scattering characteristics of trunk cylinders were analyzed by using FEKO, a three-dimensional electromagnetic scattering simulation software, and indoor multi-angle, multi-frequency backward scattering observations, and the effect of epidermis roughness on the trunk cylindrical RCS(Radar Cross-Section)was discussed. The studies included:(1)Simulated the response of the trunk cylinder RCS to the cylinder size, dielectric constant;(2)the comparison between FEKO simulation results with indoor measurement results, and(3)Explored and compared the effects of roughness in the way of simplified modeling and simulation based on real trunk meshes. The results showed that:(1)size, RCS of the cylinder gradually increased with the increase of diameter, but the change is more complex in different components of vegetation;(2)dielectric constants, RCS increased with the increase of dielectric constants, and under the experimental conditions, for every 10% increase in water content, the dielectric constant increased by about 4, RCS increased by about 1dBsm;(3)Simulations and measurements have consistent trends:R~2 was 0.87 at the highest and 0.5 at the lowest, but there was a deviation in absolute values, RMSE is between 4～6.5 dBsm, and(4)the roughness of the trunk surface had some effect on RCS, but was related to wavelength. Based on the realistic trunk mesh simulation, the surface roughness had an effect on RCS and the impact of different frequencies is:X>C> S band, and the simplified modeling method could not characterize the roughness of the trunk surface well. Using high-precision simulation and observation, the scattering characteristics of trunk cylinders were re-understood, the effects of trunk surface roughness on their scattering properties were explored, which provides an important reference for improving the modeling accuracy of vegetation cylinders.更多还原