夏玉米冠层光合有效辐射垂直分布模型

吸收光合有效辐射分量（FPAR）是研究植被群体光合作用和光能利用的重要参数，弄清冠层内FPAR的垂直分布规律及其与冠层结构等参数之间的定量关系，可以为遥感定量反演冠层FPAR提供模型基础。该文基于平均冠层的辐射传输过程，结合冠层结构建立玉米冠层内FPAR垂直分布计算模型，并就模型的参数如植被组分光学特性、株型、太阳高度角以及天空散射光比例等对FPAR垂直分布结果的影响进行了分析。利用实测结构参数模拟了玉米冠层内FPAR，并与SUNSCAN测量值进行了比较，结果表明模型对封垄后的玉米冠层内FPAR垂直分布的模拟精度较高，RMSE均小于0.18，并能较好地计算封垄前冠层内FPAR的垂直分布趋势。

Photosynthetically active radiation vertical distribution model in maize canopy

FPAR (fraction of absorbed photosynthetically active radiation) is an important parameter for estimating plants net primary productivity of land ecosystem from remotely sensed data, and is also crucial for calculating canopy APAR (absorbed PAR) and estimating canopy Photosynthesis and the utility rate of luminous energy. Based on the theory of radiation transfer model, this paper modified the Simultaneous Heat and Water model to calculate FPAR vertical distribution in maize canopy and analyzed the relationships between FPAR and some parameters like maize canopy structure, solar zenith, soil reflectance, etc. The validation results using field measurements prove the model to be accurate.