Electromagnetic scattering from short branching vegetation
Electromagnetic scattering from short branching vegetation
复制标题
DOI：
10.1109/36.841974
复制
发表时间：
2000
期刊：
影响因子：
--
通讯作者：
T. Chiu;K. Sarabandi
中科院分区：
文献类型：
--
作者：
T. Chiu;K. Sarabandi
建立了短枝状植被的极化相干电磁散射模型。该模型通过合理描述粒子相对位置的真实结构，考虑了不同粒子散射场之间的相位差所引起的相干效应，并考虑了粒子间的二阶近场相互作用，而粒子的相对位置和取向对粒子间的二阶近场相互作用至关重要。模型验证与测量，并获得良好的协议。利用车载散射计在L波段和C波段对不同土壤湿度条件下的大豆植株进行了极化雷达后向散射测量。通过广泛的地面实况，重要的植物和粗糙的表面参数，如土壤水分和表面粗糙度，植被介电常数，和几何形状的大豆植物，其特征在于模型验证。结果表明，在C波段，由于植被颗粒密度高，大豆的二阶近场散射显著，而在L波段，二阶近场散射的贡献可以忽略不计。相干效应在L波段是重要的，在C波段的程度要小得多。然后，该模型被用来证明它的能力，估计大豆田的物理参数，包括土壤水分从一组极化的AIRSAR图像。
A polarimetric coherent electromagnetic scattering model for short branching vegetation is developed. With the realistic structures that reasonably describe the relative positions of the particles, this model is able to consider the coherent effect due to the phase difference between the scattered fields from different particles, and account for the second-order, near-field interaction between particles, to which the relative positions and orientation of the particles are essential. The model validation with measurements is also presented, and excellent agreement is obtained. The polarimetric radar backscatter measurements for soybean plants using truck-mounted scatterometers were conducted at L-band and C-band under different soil-moisture conditions. Through an extensive ground truth, the important plant and rough surface parameters such as the soil moisture and surface roughness, vegetation dielectric constant, and geometry of the soybean plants, were characterized for model verification. It is found that the second-order near-field scattering is significant at C-band for fully grown soybeans due to the high vegetation particle density, and at L-band, the contribution from the second-order near field is negligible. The coherence effect is shown to be important at L-band and to a much lesser extent at C-band. This model is then used to demonstrate its ability for estimating the physical parameters of a soybean field, including soil moisture from a polarimetric set of AIRSAR images.