从几何光学(GO)模型出发,针对半干旱的草场植被,引入了多光谱冠层反射模型MSRM、土壤反射光谱Price模型以及土壤方向性反射Walthall模型,提出一种适用于区域尺度的多角度多波段反射率模型,并采用MISR和MODIS卫星数据进行验证,验证结果表明模型有较好的适用性。这为多角度、多波段遥感数据用于半干旱草场植被的定量研究提供了新的方法。

It’s awidely studied field to get the structuralparameters of the vegetationwith remote sensing data. In this\npaper, multi-spectral information is used in themulti-angular remote sensing research. A spectral-directional reflectance\nremote sensingmodel of regional-scale is presented for the semiarid grassland.\nStartingwith theGeometric-Opticalmodeling and considering the difference between the tree and the grass, twomost\nmi portant scene elements are accounted for in thismode:l bare soil and canopy. The model is composed of theMulti-\nspectralReflectanceModel(MSRM) for calculating the canopy reflectance, the soil spectral reflectance Pricemodel and\nthe soilBRDFWalthallmodel forcalculating the soil reflectance. Poissonmodel isused to calculate the percentage ofeach\ncomponentofremote sensingpixe.l Validation hasbeen done usingMISR andMODIS data for themode.l The resultshows\nthatRMS betweenmodeledmulti-angular reflectance andMISR data, andRMS betweenmodeledmulti-spectral reflectance\nandMODIS data are 5·31%, 6·37%, 4·69% and 5·14%, 4·68%, 5·71% for no degraded grassland, slightly\ndegraded grassland and badly degraded grassland respectively. The precision of our model can meet requirement of\nresearchwork.The sub model of soil reflectance is expermi enta.l The study has shown that it can be replaced by the\nmechanism mode,l for the percentage of soil is dominated especially in the badly degraded grassland.\nIn conclusion, itprovides a new approach ofapplication of remote sensing apllication to quantitative study and quick\nevaluation ofgrassland degradation in the semiarid region.