Study On The Driving Forces Of The Vegetation Cover Change In Gannan Prefecture From 2000 To 2013

As important components of the terrestrial environment, vegetation on soil erosion, keeping the atmosphere, maintaining regulated aspects of climate and ecosystem stability as a whole has an important role. Change reflects the natural evolution of the vegetation cover and the effects of human activities on ecological environment. The ecological environment in Gansu Prefecture of Gannan province is fragile, sensitive area of climate change of China, facing a serious problem of the deterioration of the ecological environment.Using the regression residuals method analysis the vegetation cover change driving force, especially, it is mainstream method to distinguish climate change and human activities the relative role. However, this method has at least two defects. First, climate change and human activities may exist "trend", to distinguish the effect is not ideal; secondly, it can not take into account the atmospheric effect of fertilization(since the industrial revolution of CO2 and elevated atmospheric NOX concentrations in vegetation photosynthesis leading to enhanced).This study is based on MODIS NDVI data sets, using the improved method of regression residuals, explore the 2000-2013 vegetation cover change and its driving forces in Gannan Prefecture, designed to provide decision support to environmental protection and ecological construction in the area.Due to the shortage of the above methods, the main works of this paper are:Without considering the effect of fertilization under the condition of the atmosphere, using ordinary regression residuals method and the improved residual method analysis of vegetation cover change in the process of climate change and human activities in the contribution rate. The results show that:(1) In recent 15 years in Gannan, the overall vegetation activity showed enhanced momentum.(2) In the regions where vegetation cover significantly increased and significantly decreased, the improved residual method recognized that the contribution of climate change is lower than ordinary regression residuals method and human activities contribute is higher than ordinary regression residual method.(3) The improved residual method can effectively separate climate change in human activities.Considering the factor of CO2, the method utilizes the improved residual method to separate the role of climate and non-climate, on the basis of combining field investigation and regression analysis method is further separated from the climate effect of atmospheric fertilization effect and the effect of artificial factor. the results show that:(1) In recent 15 years, the vegetation in Gannan prefecture as a whole increased, but this increase due to the atmospheric effect of fertilization.(2) The climate change to a certain extent help promote vegetation growth, but basically was inhibited by the negative effects of human activity and human activities in the local area, is severely damaged.In this paper, based on the regression residuals method made improvements on two aspects:(1) Using the improved residual method analysis effects of climate change and human activities on the contribution of vegetation cover change.(2) On the basis of the improved residual method considered furtherly the fertilization effect of atmospheric contribution to the vegetation coverage rate of change.In this study, analysis of the driving force for change in vegetation cover and vegetation dynamics Gannan do a preliminary study and intends to try, its conclusions follow scientific research work remains to be further verified.