Abstract: The bi-directional reflectance and structure parameters of canopy, reflectance and transmission of leaf were measured under five different nitrogen levels (0,45,135,225,315 kg/hm²). The FCR model was built to simulate the bi directional reflectance. The comparison of measured with simulated value shows that the RMSE is lower than 0.08, and the correlation coefficients are higher than 0.85. The POWELL method was utilized to invert leaf area index and leaf relative linear size, the relative errors are lower than 10% when leaf area index is more than 3.

Key words: bi-directional reflectance, nitrogen, simulation, inversion, rice, canopy

摘要： 在2000年晚稻大田试验中，设5个氮素水平，即严重缺氮、缺氮、氮适中、氮过多和氮严重过多5种不同的生长状况，实测了5种氮素水平下的水稻冠层二向反射率、叶片反射率、透射率、冠层结构参数等，利用FCR模型模拟冠层二向反射率，模拟精度用RMSE值和相关系数r检验，利用POWELL法反演冠层结构参数，当叶面积指数>3时，反演结果与实测值的相对误差小于10%。

关键词: 二向反射率, 氮素, 模拟, 反演, 水稻, 冠层