基于光线跟踪的冠层光分布模型参数研究

Parameters in the model of canopy light distribution with ray tracing approach

以烟草冠层为例,使用面向对象技术,设计虚拟传感器,以改进蒙特卡罗光线跟踪模型,获得冠层中任意位置的截光率,进而定量分析各参数对模拟结果的影响。试验结果表明:1)初始光线投放密度和冠层结构精度对模型计算结果影响较大;2)在其他参数条件不变时,增加模型跟踪深度,增大天空散射源分布密度将提高模型计算精度。最后,对比了相同时段同一烟草冠层的田间实验和模型计算得到的光合有效辐射三维空间分布,决定系数(R2)达0.98。该研究结果可为蒙特卡罗光线跟踪模型在作物冠层光分布模拟应用中提供参考依据。

The simulation in distribution of photosynthetically active radiation within plant canopy has a great significance in studying physiological and ecological processes of plant. Monte-Carlo Ray-tracing（MORT） model is one of the most effective models which are based on computer science to simulate the distribution in virtual plant canopy. The settings of parameters in MCRT model are the key point to improve the reliability of simulation. In order to get the optimal parameters,we designed a kind of virtual sensor to get the interception ratio for validating the simulated 313 PAR distribution with MCRT approach, in this paper,we utilized MCRT model to simulate the distribution of photosynthetically active radiation within tobacco canopy for quantify the impacts of parameters on simulations. Finally, we compared the results between field measurements and simulations to verify the feasibility of MCRT model. The result of this research provided with a reference for MCRT＇s application in simulating the three-dimensional light distribution in crop canopy.