Impact of water background on canopy reflectance anisotropy of a paddy rice field from multi-angle measurements
Impact of water background on canopy reflectance anisotropy of a paddy rice field from multi-angle measurements
复制标题
多角度测量水背景对稻田冠层反射率各向异性的影响
DOI：
10.1016/j.agrformet.2016.11.010
复制
发表时间：
2017-02
影响因子：
6.2
通讯作者：
Ye Yongchang
中科院分区：
文献类型：
--
作者：
Sun Tao;Fang Hongliang;Liu Weiwei;Ye Yongchang
水分背景对部分淹水植被的反射率有显著影响。然而，淹没背景对反射率各向异性的影响还没有完全了解。通过多角度观测，探讨了水分背景对水稻冠层各向异性反射率的影响。在一个淹水的水稻站点上，测量了不同视角天顶角（VZA）（−60°-60°，间隔15°）的季节性多角度反射率。提取了550 nm、660 nm、850 nm和1640 nm的波长信息，以反映冠层各向异性特征。两个冠层各向异性指数，各向异性因子（ANIF）和各向异性指数（ANIX），进行了研究，为非淹没和淹没冠层的关键物候期。结果表明，水稻冠层反射率的各向异性被一层较浅的水（约10 cm）显着削弱。当VZA > 15°时，背景水使冠层反射率降低28%，当LAI < 4.0和植被覆盖度<80%时，背景水使冠层反射率各向异性减弱。当叶面积指数> 5.0时，背景水对冠层反射率几乎没有影响。当LAI < 2.0时，1640 nm显示出最强的各向异性，而当LAI > 3.0时，660 nm显示出更显著的各向异性。对于相同的VZA，后向观测比前向观测显示出更强的散射。这项研究的数据可用作生物物理模型的输入和遥感产品的验证数据。
Water background significantly affects the reflectance of partially flooded vegetation. However, the flooded background effects on the reflectance anisotropy have not been fully understood. This paper explores the water background effects on the anisotropic reflectance of rice canopy through multi-angle measurements. Seasonal multi-angle reflectance was measured for different view zenith angles (VZA) (−60°–60° with 15° interval) in a flooded paddy rice site. Wavelengths of 550 nm, 660 nm, 850 nm and 1640 nm were extracted to show the canopy anisotropic characteristics. Two canopy anisotropic indices, the anisotropic factor (ANIF) and the anisotropy index (ANIX), were examined for both non-flooded and flooded canopies in key phenology phases. Results show that the reflectance anisotropy of rice canopy is significantly weakened by a shallow layer (≈10 cm) of water. For VZA > 15°, background water decreases the canopy reflectance by up to 28% and weakens the anisotropic properties when LAI < 4.0 and the fraction of vegetation cover (fCover) <80%. The background water shows barely no effect on canopy reflectance when LAI > 5.0. 1640 nm shows the strongest anisotropy when LAI < 2.0, whereas 660 nm shows more significant anisotropy when LAI > 3.0. The backward observations show stronger scattering than the forward observations for the same VZA. The data from this study can be used as input for biophysical models and as validation data for remote sensing products.
登录
查看更多内容
影响因子：
6.2
作者：
A. Maruyama;T. Kuwagata
通讯作者：
A. Maruyama;T. Kuwagata
影响因子：
4.3
作者：
V. K. Choubey;R. Choubey
通讯作者：
V. K. Choubey;R. Choubey
影响因子：
1.9
作者：
T. V. Niel;T. McVicar
通讯作者：
T. V. Niel;T. McVicar
影响因子：
3
作者：
T. S. F. Silva;Maycira P. F. Costa;J. Melack;E. Novo
通讯作者：
T. S. F. Silva;Maycira P. F. Costa;J. Melack;E. Novo
影响因子：
8.2
作者：
J. Susaki;Y. Yasuoka;K. Kajiwara;Y. Honda;K. Hara
通讯作者：
J. Susaki;Y. Yasuoka;K. Kajiwara;Y. Honda;K. Hara