SPOT/VEGETATION NDVI Reconstruction and Season Monitoring in China

摘要

Multi-temporal series of satellite SPOT-VEGETATION Normalized Difference Vegetation Index (NDVI) has long time-series from 1998 to present. The convenient downloading policy make those data can be widely used all through the world. The data is used for global vegetation monitoring and variation analysis. The spring onset date reflects the vegetation growth and its feedback to climate and human activity, and become an important variable for the global climatic change and production monitoring. In this paper, the spatial spring onset date information in south and central China is portrayed, and the spring onset frequency distribution map is sketched by using the multi-year 10-days composite SPOT/VGT NDVI data. First, the long time series NDVI is reconstructed. Then a relative threshold value method is given to determine whether the vegetation begins to resuscitate. The spring onset frequency map mainly parallels the latitude. But because of the heterogeneity of vegetation and monsoon, the spring onset movements do not parallel the latitude completely.