In the study of inversion of BRDF physical models Li and Strahler presented an option of inversion based onthe priori knowledge. They emphasized that to accumulate the knowledge of ground objects is important. For thepurpose of the requirement of study of BRDF physical model and the model inversion

in this article

based on thedata collected in the field experiments on different varieties of winter wheat

in Beijing

Luan Cheng of Hebei Provinceand Yu Cheng of Shandong Province in different years

the seasonal change of geometry and optics of foliagecomponents and the optics of soil background are presented. It consists of the following five contents. (1) the seasonalchange of leaf area index

(2) the seasonal change of ratio of leaf area

stem area and ear area to the sum area of thesethree foliage components

(3) the seasonal change of leaf inclination

(4) the seasonal change of optics of leaf

stem andear

(5) the seasonal change of upward reflectance of soil background. It is a set of representative results in coverage ofmain growing period

of different varieties of winter wheat in the middle part of North China Plain.