Impact of sensor footprint on measurement of directional brightness temperature of row crop canopies
Impact of sensor footprint on measurement of directional brightness temperature of row crop canopies
复制标题
传感器足迹对中耕作物冠层定向亮度温度测量的影响
DOI：
10.1016/j.rse.2013.02.025
复制
发表时间：
2013-07
影响因子：
13.5
通讯作者：
Hu Rong-Hai
中科院分区：
文献类型：
--
作者：
Ren Hua-zhong;Yan Guang-Jian;Liu Rong-Yuan;Nerry Francoise;Li Zhao-Liang;Hu Rong-Hai
传感器的足迹决定了传感器所观察到的目标，并影响目标在现场的方向亮度温度（DBT）的角度特征。本文介绍了一种新的辐射传输模型（FovMod）模拟的DBT行作物冠层在地面测量传感器的足迹。FovMod首先将传感器的圆形或椭圆形足迹划分为几个小单元，然后估计组件的分数（例如，叶、阳光照射土壤和阴影土壤）中。冠层的DBT最后通过使用传感器响应的高斯点扩展函数（PSF）对分量的亮温及其分数进行加权来获得。仿真结果表明，小的足迹导致的DBT的分布强烈地主导的行方向和单个组件的温度，但受太阳位置的影响很小。相反，较大的占地面积使行距效应平滑，并使DBT分布为均匀、连续的林冠。与以前的平行模型的比较表明，如果传感器的圆形足迹的直径延伸到行作物冠层的总宽度的1.5-2.0倍大，足迹的影响被最小化，地面测量的DBT可以，理论上，可以用来评估的平行模型，误差可以忽略不计。最后，验证与玉米冠层表明，新模型比并行模型更准确地模拟DBT。此外，FovMod还提供了一个机会来评估传感器足迹中某些意外变化引起的测量不确定性。
A sensor's footprint determines the target that is observed by the sensor, and influences the angular features of the target's directional brightness temperature (DBT) at the field site. This paper describes a new radiative transfer model (FovMod) to simulate the DBT of the row crop canopy by considering the sensor's footprint in the ground measurements. The FovMod firstly divides the sensor's circular or elliptical footprint into a few small cells, and then estimates the components' fractions (e.g., leaves, sunlit soil and shaded soil) in each cell based on the gap probability theory. The canopy's DBT is finally obtained by weighting the components' brightness temperatures and their fractions using a Gaussian point spreading function (PSF) of the sensor's response. Simulation results indicate that a small footprint causes the distribution of the DBT to be strongly dominated by the row direction and a single component's temperature but little influenced by the solar position. On the contrary, a large footprint smoothes the row-space effect and causes the DBT to distribute as a uniform, continuous canopy. Comparison with a previous parallel model shows that if the diameter of the sensor's circular footprint extends to 1.5–2.0 times as large as the total width of the row crop canopy, the footprint effect is minimized, and the ground measured DBT can, theoretically, be used to evaluate the parallel model with negligible error. Finally, validations with a maize canopy demonstrated that the new model performed more accurately than the parallel model to simulate the DBT. Moreover, the FovMod also provides an opportunity to assess the measurement uncertainty caused by some unexpected changes in the sensor's footprint.
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DOI：
10.1109/igarss.2003.1294765
发表时间：
2003-07
期刊：
IGARSS 2003. 2003 IEEE International Geoscience and Remote Sensing Symposium. Proceedings (IEEE Cat. No.03CH37477)
影响因子：
--
作者：
Tao Yu;G. Tian;Yonghong Lv;M. Legrand;Xingfa Gu;J. Hanocq;R. Bosseno
通讯作者：
Tao Yu;G. Tian;Yonghong Lv;M. Legrand;Xingfa Gu;J. Hanocq;R. Bosseno
影响因子：
6.3
作者：
Su, Z
通讯作者：
Su, Z
影响因子：
8
作者：
J. Hawkins;Thomas F. Lee;J. Turk;C. Sampson;J. Kent;K. Richardson
通讯作者：
J. Hawkins;Thomas F. Lee;J. Turk;C. Sampson;J. Kent;K. Richardson
影响因子：
6.2
作者：
N. Morrow;M. Friedl
通讯作者：
N. Morrow;M. Friedl
影响因子：
6.2
作者：
R. Myneni;J. Ross;G. Asrar
通讯作者：
R. Myneni;J. Ross;G. Asrar