Study on the Vegetation Dynamic Change Using Long Time Series of Remote Sensing Data

Under the background of global warming, vegetation is changing as climate changes. The dynamic change of vegetation is the direct indicator of the ecological environment changes. Therefore, study on the dynamic change of vegetation will be very interest and useful. The widely used NDVI was often employed to monitor the status of vegetation growth. Actually, NDVI can indicate the vigor and the fractional cover of vegetation effectively. In this paper, we selected Ningxia Hui autonomic region of China as the case study area and used 20 years pathfinder AVHRR NDVI data to carry out the case study on the vegetation dynamics in order to further understand the phenomena of 20 years vegetation dynamics of the whole Ningxia region. The results show that (1) vegetation dynamic of Ningxia presents the characters of one season per year with the length of the growth season from the first decade May to the middle decade October and the range of NDVI value 0.1-0.3;(2) from 1982 to 1999, the trend of the whole Ningxia mean NDVI is increasing and presents the stable or better vegetation growth.