The importance of forest spatial heterogeneity: Exploring the effect of mix scenes using coherence three-dimension radar backscattering model
The importance of forest spatial heterogeneity: Exploring the effect of mix scenes using coherence three-dimension radar backscattering model
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DOI：
10.1109/igarss.2016.7729184
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发表时间：
2016-07
期刊：
影响因子：
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通讯作者：
Le Yang;Qinhuo Liu;M. Moghaddam
中科院分区：
文献类型：
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作者：
Le Yang;Qinhuo Liu;M. Moghaddam
在低分辨率SAR图像中，森林与不同土地覆盖类型（如草或作物）在一个像元内组合的混合场景是常见的。多年来研制了各种雷达型号。然而，混合场景的非均质效应目前还没有得到很好的定量理解，这可能会给土壤水分和生物量的估算带来很大的不确定性。我们利用相干三维植被雷达模型研究了这一效应，该模型首先使用2013-2014年美国俄勒冈州Metolius松林的地面测量数据和机载P波段SAR数据进行了参数化和验证。机载SAR数据与模拟数据吻合较好，平均差值小于1dB，相关系数大于0.96。其次，对相同面积、相同树密度和相同树高但不同树丛模式和不同土地覆盖类型混合场景进行了模拟。最大的差异可以达到3dB的极端树丛模式。该研究表明，考虑混合场景下森林水平异质性的重要性。需要进一步研究混合土地覆被的水平异质性及其对土壤水分和生物量估算的影响。
Mix-scene of forest with the combination of different land cover types, such as grass, or crop, in one pixel is common, especially for the low resolution SAR images. Various radar models have been developed through years. However, the heterogeneous effect of mix-scene is not well understood quantitative so far, which might cause substantial uncertainty in the soil moisture and biomass estimations. We investigated this effect by using a coherence 3D vegetation radar model, which is firstly parametrized and validated using the ground measurements and airborne P band SAR data at pine forest of Metolius, Oregon, USA, 2013-2014. The airborne SAR data and simulated data are in good agreement with mean difference less than 1dB and correlation coefficient above 0.96. Secondly, Simulation of several mix-scenes of the same area, tree density and height but difference tree clumping patterns and mixed with different land cover types were performed. The largest difference can up to 3dB of extreme tree clumping patterns. This study demonstrates how important it is to consider the horizontal forest heterogeneity of mix-scene. Further study with quantitative description of horizontal heterogeneity of mix land cover and the effect to soil moisture and biomass estimation are needed.