ANIAssessment of MODIS BRDF shape indicators
评估MODIS的BRDF角度指数产品

Bidirectional Refl ectance Distribution Function (BRDF) shape indicators of Moderate Resolution Imaging Spectroradiometer (MODIS) are among MODIS BRDF/Albedo products and are helpful in expanding the application of BRDF remote sensing data. This paper evaluates the MODIS BRDF shape indicators with the statistical analysis methods by using various collected ground BRDF datasets and MODIS products. Our result presents several major fi ndings: (1) the MODIS BRDF shape indicators contain the information regarding 3-D structure of land surface and have the possibility to retrieve the structural parameters of the land surface; (2) the MODIS BRDF shape indicators are intrinsically three-dimensional. Since Anisotropic Index (ANIX) is highly related to Anisotropic Factor (ANIF) and has wider value range than the ANIF, the ANIF may be removed from the MODIS BRDF shape indicator products for refi nement of the MODIS BRDF/Albedo products; (3) Anisotropic Flat Index (AFX) is related to basically scattering types of land surface with low within-class variances, so it is considered to be more useful in improving land cover classifi cation accuracy.