Northern Tibet Grassland Vegetation Index Factor Screening and Suitability Partition

The vegetation index mainly reflects the difference between the visible and near-infrared reflectance and soil background, quantitative description of vegetation growth conditions. Data was preprocessed, 6 vegetation index was extracted, vegetation index trend was analysis in time scales based on 2013 year 5-10 month MODIS09QA image of northern Tibet grassland growth intervals. Based on the main factors of grassland growth, we described a partition of the grassland, Overlay statistics MSAVI mean information of each suitability partition , explored the weight of major influence factors on the spatial scale. It showed that: In temporal dimension, MSAVI vegetation index accord with normal distribution, R2 is 0.885, the grass growth during the changing process of vegetation coverage was consistent. In spatial scale Relative weight of impact factors: orographic influence weight was the largest, followed by water, human activities influences least.