Difference in NDVI with Altitudinal Gradient and Temperature in Qinling Area
秦岭地区植被NDVI海拔梯度差异及其气温响应

The Qinling Mountains are sensitive to climate change. Differences in vegetation NDVI across altitudinal gradients and its response to temperature in Qinling from 2000 to 2009 was carried out using MODIS NDVI images, temperature and 30m DEM data. We found that vegetation coverage is improving at Qinling and increasing year by year. This reflects the implementation of ecological policies around returning farmland to forest and grass. The average NDVI value increases and then decreases with increasing elevation in Qinling from 2000 to 2009. The maximum average NDVI value was from 1500~2000m, and the minimum value was <500m. Agricultural vegetation was mainly distributed <500m, and with increasing elevation, agricultural vegetation transitioned to broadleaf forest vegetation. Due to human interference, broadleaf forest vegetation at higher altitudes was replaced by shrub vegetation gradually leading to a small NDVI value. Vegetation coverage from1500~2000m and >2700m increased was not significant. In the past 30 years, temperature in the Qinling area has been rising at a rate higher than the national average. The correlation coefficient (0.43) between temperature and vegetation NDVI in the high altitude areas (>2700 m) was the highest, reflecting that high altitude areas of terrestrial vegetation will be more vulnerable to global climate change.