水稻冠层垂直反射率模拟

利用1999年和2000年实测的晚稻冠层结构参数(叶面积指数、叶倾角、叶长、叶宽等)和叶片生物化学组分含量(叶绿素、蛋白质、纤维素、水等)实测数据,结合椭圆分布函数模型、PROSPECT模型和FCR模型,模拟水稻冠层垂直反射率,模拟值与实测值的相关系数大于0.98,均方根差RMSE小于0.05,从而建立了冠层结构参数、叶片生物化学组成等农

Simulating Nadir Reflectance of Rice Canopy

Measuring rice canopy structure parameters (such as leaf area index, leaf inclination, leaf length, leaf width) and leaf biochemistry contents (such as chlorophyll, protein, cellulose, water) in 1999 and 2000. Then simulate rice canopy nadir reflectance by those measured datum. The simulating models are elliptical model, PROSPECT model and FCR model. The three steps are: (1) We simulate leaf inclination distribution by elliptical model. The input parameters are model leaf inclination and eccentricity of the elliptical distribution of leaf normal which are 81 and 0 9985. The output parameter is leaf inclination distribution function. The correlations between simulated and measured are more than 0 95, and the RMSE is less than 0.03; (2) We simulate leaf reflectance and transmittance by PROSPECT model. The input parameters are leaf structural parameter and leaf chemicals (chlorophyll, protein, cellulose, etc). In the model, the leaf structural parameter equals to 1.7, while the leaf chemicals are measured datum. The correlations between simulated and measured are more than 0 95, and the RMSE is less than 0.02; (3) We simulate canopy nadir reflectance by FCR model. The parameters we need for input are optical parameters (leaf reflectance, leaf transmittance, reflectance of background on nadir view direction, refractive indices of the leaf surface wax, etc), structural parameters (leaf area index, leaf inclination distribution, relative linear size of leaves, etc) and view and illumination geometry (sun zenith angle, view zenith angle, the ratio of direct to total indices radiance). Some of the parameters are calculated in (1) and (2), some are measured, and others are valued by conference. The correlations between simulated and measured are more than 0 98, and the RMSE is less than 0.05. So, by these models, canopy structural parameters and leaf biochemistry content are directory connected to canopy reflectance. It is significant in leaf area index and chlorophyll inversion by physical model.