Effect of Grazing Systems and Oversowing on Grassland Covering of Northern Tibet Monitored by Remote Sensing Methods of Land-cover Dynamic Monitoring Base on CBERS Data Assessing the Capability of CBERS-02 B CCD for Estimating Subtropical Forest above Ground Carbon Storage Monitoring sandy desertification of the Otindag Sandy Land based on multi-date remote sensing images A Primary Study on Nitrogen Content of Rice Leaf Based on Remote Sensing at Spiking Stage