Spectral characteristics of alpine grassland with different degrees of desertification in Maqu County, the source region of the Yellow River

• CHEN Zhengrong, 
• YANG Xuemei, 
• TANG Jinnian, 
• ZHANG Zhong, 
• LI Yinke, 
• ZHANG Weixing, 
• WANG Jingrui, 
• LI Xuemin