Analyze The Change And Driving Factors Of NDVI In Altay District

Global warming and unreasonable human activities cause the deterioration of vegetation cover in Altay district thus make a huge impact to the local ecological environment and bring certain economic losses to agriculture, forestry and animal husbandry production at the same time. This paper combined the geographic information system and remote sensing technology to analyse the temporal and spatial variation characteristics of NDVI during 2000 to 2013 and explore the relevant driving factors of it.The main conclusions are as follows:(1) The change tendency of annual average NDVI was increased during 2000 to 2013 in Altay district, and the increase rate was 0.002/10 a which indicates the vegetation cover condition improved. The spatial distribution of NDVI which in the Northeast area is higher than it in the South area. The area improved( 20336.76 km2) is larger than the area decreased( 5213.85 km2).(2) Average NDVI indicates different degrees of growth trends in Altay district during 2000 to 2013 according to the season and the growing season. The growth rate in Spring is 0.003/10 a, Summer-0.0001/10 a, Autumn 0.009/10 a and Winter is 0.007/10 a, the growing season 0.006/10 a. There are some difference between average NDVI and changeable trends of different vegetation types, land usage types.(3) The correlation coefficient between annual average NDVI and annual temperature is higher than the annual precipitation. From the spatial distribution, the area of Altay region’s annual average NDVI and annual temperature which reaches positive correlation is higher than it did proportion of negative. Each month average NDVI and 1-5 months before the temperature, precipitation there is a certain lag.(4) According to the influence of terrain on the NDVI changes caused by elevation, slope, aspect in three areas, we can found that the difference of NDVI of different elevation, slope and aspect is clearly.(5) Human activities, economic development will have a certain impact on the changes of NDVI.The effect from Oasis to NDVI changes is that the farther from the oasis distance, the smaller average annual NDVI was, NDVI changing rate would be gradually decreased.