Quantitative Analysis Of Spatial And Temporal Change And Dynamics Of NDVI In Hunan Province From 2000 To 2017

Hunan province is a big forestry province in China,its forest coverage is 59.68%,it ranks sixth in China.So it is of great significance to study the temporal and spatial change and driving force of NDVI of vegetation in Hunan province to evaluate the change of vegetation cover and its influential factors and promoting the sustainable development of ecology and social economy in Hunan province.In this paper,we use the dataset of MODIS-NDVI,Comparing the change of land use data in Hunan province to evaluate the contribution of climate and human activities to NDVI change.Constructing complex linear regression equation to predict the future normalized vegetation index data(NDVI)of Hunan province.The main research conclusions are as follow:(1)The annual mean value of NDVI in Hunan province from 2000 to 2017 show a significant growth trend(P<0.05)and presented seasonal trend.From 2000 to 2017,NDVI in Hunan province shows a significant spatial change,96.49%of Hunan province of NDVI increase,with 80.61%of Hunan province of NDVI shows a significant increase,The areas with reduced normalized vegetation index accounted for 3.51%of the total area of the province,the descreation of NDVI mainly distribut in some place of Changsha,Zhuzhou,Changde and Hengyang.(2)The normalized vegetation index(NDVI)in Hunan province is affected by percipitation,temperature and human activities,and show significant spatial heterogeneity.According to the study,the significant increase of NDVI is mainly distributed in the northwest region of Hunan province.According to the calculation of the contribution ratio of human and climate to NDVI changes,climatic factors are larger than human activities.Meanwhile,urbanization plays a promoting role in the vegetation restoration in some areas of Changsha,Hengyang and Zhuzhou in Hunan province.(3)According to the results of residual analysis,the positive effect of human activities on NDVI increased from 31.3%in 2000 to 78.3%in 2017.According to the distribution of GDP and population density grid data in Hunan province,the higher the GDP,the slower the vegetation recovery is.In the areas with high population density,and the faster the vegetation recovery is in the areas with low GDP and population density.To sum up,80.61%of Hunan province of vegetation cover significantly increase.In term of climatic factors,the effect of temperature on the normalized vegetation index in Hunan province is stronger than that of precipitation.According to the results of residual analysis,the positive effect of human activities on the change of vegetation cover in Hunan province has increased year by year in the past 20 years.