Crop specified albedo model based on the law of energy conservation and spectral invariants

A physical model for simulating crop albedo based on the law of energy conservation and spectral invariants was developed. The idea referred to the primary PARAS albedo model for forest. The developed model concerned two key problems for crop monitoring, one is the anisotropy of soil reflectance and the other is the clumping effect of crop leaves at canopy scale, which contributed to the improvement of the model accuracy. The comparison between the model results and those simulated using a Monte Carlo method shows that the calculated clumping index, soil absorptance and canopy albedo all have high accuracy, indicating that the model is able to reflect the interaction mechanism between radiation and the canopy-soil system.