Variations And Impact Factors Of Vegetation Cover In Inner Mongolia Based On The Modis-Ndvi

Distinguish the influences from climate change and human activities on changes in vegetation by studying the relationship between them is one of the hot issues of ecology in recent years.We Used the methods of regression,correlation, residual analysis and the technique of GIS space to analysis the relationship between climate change、 human activities and trend of vegetation,based on the MODIS NDVI datasets,month average temperature and precipitation from meteorological stations in Inner Mongolia from2001-2013. The results showed that:(1) In recent13years,10.62%of the vegetation cover had been grown significantly,which were mainly located in the typical steppe of Inner Mongolia;1%of the vegetation cover of Inner Mongolia had been decreased significantly,which were mainly located in the Coniferous forests and forest savanes.the maximum time of vegetation of seven zone from east to west were changed in turns.(2) There were no significant linear trend of annual and seasonal temperature and precipitation in Inner Mongolia from2001-2013. the maximum value of temperature and precipitation appeared in july.Among the48stations sites, eight meteorological sites showed a significant reduction trend in annual average temperature, mostly distributed in the central of Inner Mongolia, annual precipitation was significantly increased in five sites located in the eastern, only one site annual precipitation was significantly reduced located in the west. A month ago of temperature and monthly precipitation has the maximum correlation coefficient with NDVI, the correlation coefficients between temperature、 precipitation and NDVI were the largest in autumn, the correlation coefficients between temperature and NDVI was larger than precipitation and NDVI in spring and autumn,but it has the opposite result in summer, and in this season, the impact of temperature and precipitation on NDVI has a long time. In spatial scales, the lag time between temperature、 precipitation and NDVI were mostly for a month except some sites in the northeast of Inner Mongolia,it has no lag time between temperature、 precipitation and NDVI, and the maximum correlation coefficient of temperature is generally greater than precipitation. The space distribution state of the maximum correlation coefficient between temperature and NDVI time is northeast> middle>west, the space distribution of maximum lag time between vegetation NDVI and precipitation was central west> northeast,space distribution feature was middle> east and west(3) There were significant spatial differences relationships between vegetation NDVI and temperature, precipitation.The most typical was the significant positive relationships between NDVI and temperature in east,NDVI with precipitation in desert-steppe region.Used the method of residual analysis of characterized the human activities to quantify the situation of human activities in recent years, it was found that the siginificant change of vegetation NDVI were mainly influenced by artificial factors under the background of no siginificant change of temperature and precipitation. It was to provide scientific decision basis for further reasonable organization of human activities in Inner Mongolia,based on the accurate interpretation of process and cause of the vegetation change in Inner Mongolia.