To Evaluate the Vegetation Dynamic in Northern-Tibet Plateau of China Based on Remotely Sensed Information and Meteorological Data

A ten-day interval of satellite data (NOAA/AVHRR) between 1981 and 2001 were used to investigate the Vegetation dynamic in Northern-Tibet Plateau (NTP), China. The relationships between NDVI and climatic parameters were analyzed in six counties of NTP. And the human activities factors such as population also tested in this study. The result shown that the prominent increase and decrease of NDVI occurred in middle eastern and eastern NTP with low altitude. Correspondingly, the linear trends of VP-NDVI were weak and no change in western part of the NTP with high altitude. The strong negative relationship between NDVI and evapotranspiration occurred in sub-frigid semi-arid and frigid arid regions, e.g., Nakchu, Shantsa, Palgon and Amdo counties, which indicated that the evapotranspiration was main effecting factor on vegetation degradation in these areas. But in temperate-humid and sub-frigid semi-humid regions, significantly negative correlations imply that human activities had primary influenced on vegetation degradation like Chali and Soksa counties.