Vegetation cover changes and its relation with climate factors in Chongqing

In this paper,we analyzed the spatial characteristics and the changes rule of vegetation coverage based on the 250 m MODIS-NDVI data from 2000 to 2011 in Chongqing,and investigated its relation with climate factors in different time and space scale,by integrating NDVI with climate data.The results as follow:(1)The vegetation cover presented entirely an upward trend.Among the seasonal variation,vegetation coverage increased obviously in winter,spring and autumn.(2)From the trend of spatial variation,vegetation coverage increased significantly in the northeastern and southeastern of Chongqing,while it reduces in the metropolitan and the center town area.(3)The correlation of NDVI and temperature was greater than the correlation with precipitation.The positive correlation and negative correlation of annual average NDVI and annual average precipitation and temperature were coexistence in Chongqing area.The significant positive correlation region was larger than the significant negative correlation area.But the correlation was not significant in most regions.(4)There was a certain time lag effect of temperature and precipitation on vegetation growth,the time-delay effect of precipitation was more obvious.