Response characteristic analysis of climate change of vegetation activity in Huang-Huai-Hai area based on NOAA NDVI data set

Based on 1982-2003 GIMMS NDVI soundings and climate data by use of techniques for the trend, correlation and SVD analysis, this work is devoted to the space/time patterns of the response to climate change of the vegetation activity in the Huan-Huai-Hai area (HHHA). Results suggest that the area shows a more significant warming trend and less distinct aridization, on the whole, with annual mean NDVI displaying a marginally increasing trend. On a yearly basis, NDVI is the most sensitive to climate factors, and annual temperature, rainfall and relative humidity (evaporation) exert positive (negative) effect on the dynamic variation in vegetation NDVI. On a seasonal scale, temperature and rainfall are the most strongly influencing factors, with autumnal climate having heavier impact on yearly mean NDVI. Natural vegetation is predominantly sensitive to rainfall and, to a less degree, to temperature; agricultural vegetation is sensitive dominantly to temperature and, to less extent, to rainfall. April - September vegetation response to climate has the space patterns as follows. The anomaly field of NDVI has 1) the same structure as that of temperature, 2) an anti-correlation structure with anomalies of evaporation, 3) a see-saw distribution with positive (negative) correlation in the north (south) with that of rainfall anomalies, and 4) an opposite distribution with positive (negative) correlations in the south (north) to that of relative humidity.