Spatio-temporal change of vegetation NDVI and its relations with regional climate in Northern Shaanxi Province since implementation of returning farmland to forests project

Correlation analysis, spatial statistical and overlay analysis are adopted to investigate spatial distribution pattern and variation characteristics of vegetation NDVI, and to analyze the relations between vegetation NDVI and regional climate from the views of temperature and precipitation respectively. It is found from the research that the vegetation NDVI change undergoes three stages: relatively-rapid growth stage from 2000 to 2002, slightly fluctuating stage from 2003 to 2005, and steady growth stage from 2006 to 2010. Vegetation NDVI change varies in different space: in loess hilly area in the central and eastern region of Northern Shaanxi Province, the vegetation cover increased significantly.in the wind drift sand area in the northern region, the change in vegetation cover was small. in low-mountain hilly area in the southern region, the vegetation cover slightly decreased. The precipitation was going on a declining curve from 2000 to 2010, while the temperature was undergoing an upward trend in the same period, but this dry-heating climate has been slightly restrained over the past years. The vegetation cover is positively related to precipitation and temperature in some areas,while in other areas it is negative. The linear relation is not obvious.