Dynamic variation of NDVI in Laoha River Basin and its relationship with climatic factors

The annual and inter-annual variation of the NDVI of forest land,shrubs,grassland and farmland and its relationship with the air temperature and precipitation in Laoha River Basin were studied using unary linear regression analysis,Pearson correlation analysis and partial correlation analysis based on GIMMS/NDVI data,temperature data from the Chifeng meteorological station and precipitation data from 52 stations from 1982 to 2006.The test results show that the annual variation of NDVI is unimodal,and the maximum value occurs in August.The monthly NDVI exhibits a positive correlation with the air temperature and precipitation and shows a logging phenomenon.The influence of the precipitation on NDVI in the forest land is relatively smaller than that in the shrubs and grassland.The influence of the air temperature on the annual growth of vegetation is larger than that of the precipitation.The average inter-annual NDVI in the basin had an increasing tendency from 1982 to 2006,and the most satisfactory performance of NDVI appeared in the 1990s.The NDVI during summer is negatively correlated with the air temperature in the corresponding and previous periods and positively correlated with the precipitation in the previous period.The increase of the air temperature in summer in Laoha River Basin results in a decrease of vegetation,and the increase of the precipitation supports the growth of vegetation.