| 模型ID： | M00037 | ||||||
| 模型名称： | 三维森林雷达后向散射模型 | ||||||
| 模型编码者： |
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| 模型关键字： | 森林、三维场景、雷达、后向散射系数 | ||||||
| 模型类型： | 理论模型 | ||||||
| 模型最后修改日期： | 2014/9/17 0:00:00 | ||||||
| 模型提交日期： | 1998/11/3 0:00:00 | ||||||
| 模型摘要： | 三维森林雷达后向散射模型是在美国马里兰大学地理系孙国清教授和美国宇航局戈达德飞行中心Jon Ranson 教授联合开发的“"A three-dimensional radar backscatter model of forest canopies”的基础上，引入marix-doubling方法，提高了模型对交叉极化的估算能力。该模型建立在由三维体元构成的三维森林场景的基础上，可以同时考虑森林空间结构在水平方向和垂直方向上的不均一性。模拟不同森林结构条件下的全极化雷达后向散射系数。其所考虑的散射分量包括：冠层直接后向散射、树干直接后向散射、地表直接后向散射、冠层-地表二次散射和树干地表二次散射。 | ||||||
| 公式： |
| 1 |
名称： leaf shape
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参数类型：String
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物理意义：树叶的形状
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| 2 |
名称：雷达入射角
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参数类型：double
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物理意义：雷达入射角
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| 3 |
名称：模拟的雷达波段
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参数类型：String
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物理意义：模拟的雷达波段
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| 4 |
名称：树枝平均长度
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参数类型：double
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物理意义：树枝平均长度
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| 5 |
名称：最小胸径
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参数类型：double
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物理意义：最小胸径
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| 标题： | A three-dimensional radar backscatter model of forest canopies | |||||||||
| 文献作者： |
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| 文献引用： | Geoscience and Remote Sensing, IEEE Transactions on | |||||||||
| 文献摘要: | A three-dimensional forest backscatter model, which takes full account of spatial position of trees in a forest stand is described. A forest stand was divided into cells according to arbitrary spatial resolution. The cells may include “crown”, “trunk”, and “gap” components, determined by the shape, size and position of the trees. The forest floor is represented by a layer of “ground” cells. A ray tracing method was used to calculate backscattering components of 1) direct crown backscatter, 2) direct backscattering from ground, 3) direct backscattering from trunk, 4) crown-ground scattering, and 5) trunk-ground scattering. Both the attenuation and time-delay of microwave signals within cells other than “gap” were also calculated from ray tracing. The backscattering Mueller matrices of these components within the same range intervals were incoherently added to yield the total backscattering of an image pixel. By assuming a zero-mean, multiplicative Gaussian noise for image speckle, the high-resolution images were aggregated to simulate a SAR image with a given spatial resolution and number of independent samples (looks). A well-characterized 150 m×200 m forest stand in Maine, USA, was used to parameterize the model. The simulated radar backscatter coefficients were compared with actual JPL SAR data. The model gives reasonable prediction of backscattering coefficients averaged over the entire stand with agreement between model and data within 1.35 dB for all channels. The correlations between simulated images and SAR data (10 by 15 pixels) were positive and significant at the 0.001 level for all frequencies (P, L, and C bands) and polarizations (HH, HV, and VV) |
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