Research on the Variation of Vegetation NDVI and Its Relationship with Climatic Factors in Northern China

Based on the remote sensing data, NOAA/AVHRR NDVI and meteorological data of 56 meteorological stations,temperature and precipitation, during 1982-2006 in the Northern China, the inter-annual variability of vegetation NDVI, temperature and precipitation and the response of NDVI to the temperature and precipitation were analyzed from monthly, seasonal and growing season time scales. From the monthly, the inter-annual change of vegetation NDVI and temperature were mainly increased, while the precipitation was mainly reduced. In view of the season, the spatial distribution of NDVI in spring was consistent with the distribution in autumn, but contrast with the distribution in summer. The time series NDVI in spring and autumn were increased, and the decreased trend in summer was weak. The rate of temperature increasing in spring was the fastest, and the summer followed. The precipitation in spring and autumn were induced, while the precipitation in summer was increased. In the growing season, the vegetation NDVI showed an increasing trend, the temperature increased 0.48 ℃ every 10 years(P0.01), while the trend of precipitation was not obvious. The vegetation NDVI in March, April and November was mainly affected by the temperature. The correlation coefficients between NDVI and temperature of the season and growing season were greater than the correlation coefficients between NDVI and precipitation. The order of the correlation coefficients between NDVI and temperature was: growing season spring autumn summer, while the order of the correlation coefficients between NDVI and precipitation was: springgrowing seasonsummer autumn.