Surface reflectance varies with solar radiance and observation angles and is usually described with a bidirectional reflectance distribution function (BRDF). The surface BRDF is important for remote sensing retrieval of vegetation canopy biophysical and biochemical parameters.
Background properties could affect the canopy reflectance. However, current studies have mainly focused on soil background. More studies are necessary for partially submerged vegetation types with a shallow water background.
Dr. SUN Tao, LIU Weiwei, YE Yongchang and Prof. FANG Hongliang from the Institute of Geographic Sciences and Natural Resources Research (IGSNRR), Chinese Academy of Sciences conducted a seasonal reflectance measurement in 2015 for paddy rice field in suburban Beijing. Canopybidirectionalreflectance in different growing stages was compared for both flooded and non-flooded conditions.
They found that the water background affects the canopy reflectance anisotropy when the leaf area index is less than 4.0. Results from this study can be useful for canopy radiative transfer modeling and remote sensing parameter retrieval.