Research on Simulation of the PAR Distribution in Tree Canopy
林木冠层光合有效辐射分布模拟的研究

The common methods about research on the distribution of radiation in canopy are introduced.The principle of ray-tracing technology and its application in radiation transmission are described.A radiation transfer model is proposed for tree model based on forward ray tracing.The model hypothesis,processing flow and primary algorithm are expounded.Forward ray tracing is used to simulate transmission course of photosynthetically active radiation in tree canopy.Finally the special conversion method between HSV and RGB color space is adopted to clearly express distribution of radiation in canopy.On the basis of analyzing optical characteristics of leaves,the radiation transfer model is applied in the simulation of distribution of PAR in canopy.At the same time,we can get the reflectance rate,transmission rate and absorption rate.The simulative data have little difference with the actually measured data which indicated that the radiation transfer model based on forward ray tracing is effective.