枇杷冠层内光分布模拟及光截获分析

Simulation of light distribution within loquat canopy and analysis of light interception

为定量分析植物冠层结构对光截获的影响,以枇杷树为研究对象,模拟冠层内光的空间分布以及随时间变化情况.实地测量获取树木形态结构参数,建立精细的三维虚拟植物模型,运用辐射度算法模拟光在冠层内的传输过程,分析冠层内光分布并以可视化的形式表达.采用光截获效率分析指标STAR和相对光合有效辐射RPAR,探索冠层内光截获效率空间分布和日变化情况.结果表明,枇杷冠层内光主要分布在向阳面的外围及中上层区域,背阴面的内膛及中下层区域光截获效率较低.

In order to quantitatively analyze the influence of plant canopy structure on light interception,taking the loquat tree as an example,this paper focuses on simulating the spatial distribution and temporal variation of light in canopy. Field measurements are carried out to obtain the structural parameters of loquat trees,and a detailed three-dimensional virtual plant model is built. Simulate the transmission process of light in canopy using radiosity algorithm,analyze the light distribution in canopy and present it in a form of visualization. The light interception analysis indicators,i.e. silhouette to total area ratio（STAR） and relative photosynthetically active radiation（RPAR）,are used to study spatial distribution and diurnal change trend of light interception in canopy. The result shows that light in the loquat canopy is mainly distributed in the periphery and upper and middle regions by the sunlight side,while the inner and lower regions by the shay side show lower light interception efficiency.