L-Band Reflectivity of a Furrowed Soil Surface
L-Band Reflectivity of a Furrowed Soil Surface
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DOI：
10.1109/tgrs.2010.2091720
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发表时间：
2011-01
影响因子：
8.2
通讯作者：
I. Völksch;M. Schwank;C. Mätzler
中科院分区：
文献类型：
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作者：
I. Völksch;M. Schwank;C. Mätzler
在实验和模型相结合的研究中，我们研究了具有周期性地形（犁沟）且尺寸接近 21 cm 观测波长的沙土的热 L 波段特征。测量是用安装在塔上的辐射计进行的，瞄准具有人工准备的有沟土壤表面的土壤箱。相应的反射率是通过在干燥和潮湿条件下进行的亮度温度测量得出的，其中沟槽方向沿着或垂直于入射平面。结果表明，犁沟对反射率有显着影响，具体取决于观测到的辐射的偏振、犁沟的方向和土壤湿度。介电周期性表面的物理反射率模型用于解释不同犁沟方向和土壤含水量测量的土壤反射率。与菲涅耳反射率相比，使用该模型大大提高了测量反射率和建模反射率之间的一致性。观察到的土壤反射率对犁沟方向和土壤湿度的依赖性可以通过反射率模型重现。通过使用简单的经验方法来考虑表土层的小尺度异质性，进一步提高了与观测到的反射率的定量一致性。
In a combined experimental and model study, we investigated the thermal L-band signatures of a sandy soil with periodic topography (furrows) with dimensions close to the observation wavelength of 21 cm. Measurements were carried out with a radiometer mounted on a tower and aimed at a soil box with an artificially prepared furrowed soil surface. Corresponding reflectivities were derived from brightness temperature measurements performed under dry and moist conditions, with the furrow direction either along or perpendicular to the plane of incidence. Results showed that the furrows had a pronounced effect on the reflectivity, depending on the polarization of the observed radiance, the direction of the furrows, and the soil moisture. A physical reflectivity model for dielectric periodic surfaces was used to explain the soil reflectivities measured for the different furrow directions and soil-water contents. Using this model improved the agreement between the measured and modeled reflectivities considerably compared to the Fresnel reflectivities. The observed dependence of soil reflectivity on furrow orientation and soil moisture could be reproduced by the reflectivity model. The quantitative agreement with the observed reflectivities was further improved by using a simple empirical approach to consider the small-scale heterogeneity of the top soil layer.