Retrieval of fractional vegetation cover of alpline grassland and the efficiency of remote sensing retrieval in the upper of Shule River Basin

In the present study, we analyzed the seasonal changes of fractional vegetation cover (FVC) of alpine grassland during the whole growing season and discussed the efficiency of remote sensing retrieval using Chinese environmental satellite (HJ-1A/1B) images and field data. The results showed that the distribution of FVC presented a reversed “U” curve with fluctuations in the middle during the whole growing season; There were good linear correlation between the measured FVC and normalized difference vegetation index (NDVI) calculated from HJ image in growing season. The slopes of fitted linear models performed as parabolic curve with the vertex as the theoretical peak of growing season. In addition, compared with single maximum value composites (MVC) and single-day methods, the inversion of double MVC method was the most accurate and closed to the “True” value. The inversion results of single MVC method and double MVC method had similar trend, however, the former was significant underestimation. The single-day method did not appear the same trend with a little underestimation compared with single MVC method.