Retrieval and analysis of grassland coverage in arid Xinjiang, China and five countries of Central Asia

Because the low grassland coverage in the arid region causes the weak spectral information, grassland coverage retrieval becomes quite difficult. Comparing four remote sensing retrieval models, we found that the pixel dichotomy model can generally retrieve grassland coverage with higher accuracy. We further produced time-series (2000-2013) of grassland coverage based on the pixel dichotomy model and analyzed grassland conditions over Xinjiang and five countries of Central Asia. Results showed that grassland coverage showed large spatial heterogeneity in the study area. Grassland generally showed degradation trends, especially in the northern and western regions and some basins of Kazakhstan. Grasslands with medium, medium-high, and high grassland coverage were converted into the grasslands with low and medium-low grassland coverage. Grasslands in Kazakhstan degenerated significantly, while the average value of grassland coverage in Xinjiang was significant growth steady.