Bi-directional normalized difference vegetation index:concept and application

The data products of land surface bi-directional reflectance distribution function (BRDF) from the space-borne Polarization and Directionality of the Earth Reflectance (POLDER) of France and the Moderate Resolution Imaging Spectroradiometer (MODIS) of USA are available recently- but the atmospheric correction for meeting the requirement of quantitative remote sensing is still a very difficult problem. This paper presents a concept: bi-directional normalized difference vegetation index (Bi-NDVI)- in order to consider simultaneously the effects of both land surface BRDF and atmospheric path scattering. An atmospheric quality index is thus defined for satellite multi-angular observations. The quality of MODIS/BRDF data products can be improved notably through iterative inversion weighed by this index.     

连续变量差分方程的振动性

利用特征方程,得到了关于连续变量差分方程x(t τ)-x(t) ∑ from i=1 to m qix(t-σi)=0其中τ,qi,σi∈(0,∞)(i=1,2,…,m),所有解振动的充要条件和几个显式的充分条件.